Hamza Bennani
email: h.bennani@parisnanterre.fr.

Does People's Bank of China Communication Matter? Evidence from Stock Market Reaction

Keywords: Central Bank Communication, People's Bank of China, Tone, Financial Markets JEL classification: E52, E58

This paper tests whether the communication of the People's Bank of China affects market expectations and matters as a monetary policy tool. For that purpose, we first rely on a computational linguistic tool to measure the tone of PBC speeches and second, we use a high frequency methodology to estimate the effect of tone on stock price. Our results show that positive changes of the tone affect positively stock price in the Shanghai and the Shenzhen stocks markets. Additional extensions show that PBC communication still has a positive and significant impact on stock price even when controlling for all the monetary policy instruments implemented by the central bank, but that this impact is not persistent over time. One potential channel through which PBC tone affects stock prices is the risk-based channel of monetary policy.

I Introduction

China's rising impact on global financial and economic markets has attracted a growing number of the People's Bank of China (PBC) watchers. The PBC watchers are thus increasingly paying attention to PBC communication to understand its monetary policy stance and to adjust their expectations of future monetary policy. 1 Since central banks aim to manage market expectations of future monetary policy and that the latter are important in determining asset prices [START_REF] Blinder | Central bank communication and monetary policy: A survey of theory and evidence[END_REF], we test the impact of PBC communication on stock market to assess whether communication affects market expectations and matters as a monetary policy tool.

This paper fits into the literature that studies the link between monetary policy and stock market. This literature suggests that the most direct effects of monetary policy, including central bank announcements, 2 are on the financial markets. More precisely, changes in monetary policy are transmitted through the stock market via changes in the values of private portfolios (the wealth effect) or changes in the cost of capital. As an illustration, [START_REF] Bernanke | What explains the stock market's reaction to Federal Reserve policy?[END_REF] estimate that the CRSP value-weighted index increases by 1% in response to a surprise 25-basis-point easing. They suggest that this impact comes through its effect on expected future excess stock returns or on expected future dividends. Jansen (2008) argues that the ability of central banks to effectively communicate and to move market expectations can also be measured by market reaction. Following this line of thought, Gurkaynak et al. (2005) show that asset prices react to the Federal Open Market Committee (FOMC) statements. They find that FOMC statements exert their effects on financial markets through their influence on market expectations of future policy actions. [START_REF] Ehrmann | Explaining Monetary Policy in Press Conferences[END_REF], Reeves and Sawicki (2009) and [START_REF] Andersson | Monetary policy signaling and movements in the term structure of interest rates[END_REF] show similar evidences for the European Central Bank, the Bank of England and the Riksbank, respectively. However, far nothing is known about the impact of PBC communication on stock market even though there is an increase of PBC transparency and communication since 2001 [START_REF] Garcia-Herrero | China's monetary policy communication: Money markets not only listen, they also understand[END_REF]. The PBC publishes statements summarizing the meetings of its Monetary Policy Committee and its governing body delivers speeches about monetary policy and the economic outlook. Therefore, given the unobserved nature of many of the monetary policy instruments implemented by the PBC, 3 its communication provides news which are likely to raise the signal-to-noise ratio and to move asset prices. This is shown by [START_REF] Xiong | Measuring the monetary policy stance of the People's bank of china: An ordered probit analysis[END_REF] who constructs an index of monetary policy based on PBC statements. The author codes PBC statements and uses this variable to estimate a monetary policy rule. He finds that his rule works better than if based on interest rates only and concludes that "words" help "deeds" in order to understand PBC monetary policy. Nevertheless, one should bear in mind that the PBC does not have full decision-making power over its objectives and instruments and has limited operational independence.4 Thus, the central bank is constrained in the forward guidance it can provide regarding the timing of important monetary policy decisions [START_REF] Mcmahon | China's Monetary Policy Communication: Frameworks, Impact, and Recommendations[END_REF]. Furthermore, recent theoretical and empirical evidences show that sentiment determines how market participants change their expectations [START_REF] Angeletos | Sentiments[END_REF][START_REF] Angeletos | Quantifying Confidence[END_REF][START_REF] Benhabib | Sentiments and Aggregate Demand Fluctuations[END_REF]. Since sentiment can be considered as information conveyed through the tone of central bank communication [START_REF] Hubert | Central Bank Sentiment and Policy Expectations[END_REF], market participants not only pay attention to the content but also to the tone of central bank statements, i.e. to how the central bank expresses its policy decisions and the economic outlook. Quantifying the tone of PBC statements is thus important to assess if and how PBC communication moves asset prices and thus, shapes market expectations.

Against this background, this paper aims to contribute to the existing literature by testing the impact of the tone of PBC communication on stock market. For that purpose, we first use PBC speeches to quantify the tone of PBC communication. Using speeches provides several advantages: (i) speeches are scheduled in advance, (ii) are closely followed by market participants, (iii) do not concur with policy meetings and thus, allow to measure the impact of tone on asset prices without confounding effects from actual policy decisions. To measure the tone of PBC speeches, we use a bag-of-words approach and the financial dictionary developed by [START_REF] Loughran | When is a liability not a liability? Textual analysis, dictionaries, and 10Ks[END_REF] to identify negative words in a speech. We compute the tone of the speech by assessing the prevalence of negative words in it and construct a measure showing the relative degree of negative or positive tone of the speech. Second, we use a high-frequency methodology to estimate the effect of tone on stock price, such as in [START_REF] Kuttner | Monetary policy surprises and interest rates: Evidence from the Fed funds futures market[END_REF] and [START_REF] Cochrane | The Fed and interest rates: A high-frequency identification[END_REF]. This procedure consists in focusing on movements in stock price in a narrow window around the speech. 5 The assumption underlying this empirical procedure is that, if PBC communication affects the returns on stock market, the volatility of these returns should be higher on days of speech, because the signal contains news. The closest papers to ours are [START_REF] Hubert | Central Bank Sentiment and Policy Expectations[END_REF] and Schemling and Wagner (2016). These papers use computational linguistics to measure the tone of FOMC and ECB statements and to show their impact on the term structure of interest rates and stock returns, respectively.

The contributions of this paper in this literature are two-fold: we are the first to measure the tone of PBC communication and to analyze its effect on Chinese stock market and thus, on market expectations. Our results show that the tone of PBC communication has a statistically and economically significant effect on stock market even when controlling for economic and financial conditions. We provide empirical evidences showing that positive changes of the tone affect positively stock price in the Shanghai and the Shenzhen stocks markets. Additional extensions show that PBC communication does not have a persistent effect on stock price and that the tone of PBC still has a significant impact on stock price even when controlling for all the monetary policy instruments implemented by the central bank.

Overall, this paper highlights that the tone of PBC communication affects stock price by signaling more or less negative tone. These results provide policymakers further insights on how financial markets interpret and respond to the tone conveyed by PBC communication and show that PBC tone brings additional information to market participants. The policy conclusion is that PBC communication is a monetary policy instrument that matters to move stock price and to shape market expectations. The remainder of this paper is structured as follows. Section 2 describes the data. In section 3, we explain our estimation procedure. Section 4 presents the results while section 5 and 6 provide additional extensions and robustness tests, respectively. The last section concludes.

II Data

II.1 Tone of PBC Communication

Since the objective of this paper is to test the impact of the tone of PBC communication on stock price, we need to use a communication tool with a precise timing. Hence, we use PBC speeches given that they are covered live by the media and are thus immediately available to market participants.

The first challenge for measuring tone is to convert PBC speeches into a quantitative measure that can be analyzed. We first collect speeches made by PBC officials and available through the Bank of International Settlements (BIS) database. 6 Speeches from the BIS are available in real time, translated in English by a dedicated team of experts and are more appropriate for textual analysis than the speeches published in the PBC website which suffer from a poor quality translation. Moreover, the financial dictionary used to compute the tone of PBC communication is in English, hence, PBC speeches need to be translated in English. We obtain in total 100 speeches delivered during the period 1996M09-2015M01. It is worth emphasizing that these speeches were made publicly (for instance, in (inter)national conferences, seminars or forums), however, they were not delivered in a regular manner as shown by figure 1 below.

6 https://www.bis.org/list/cbspeeches/index.htm. As a second step, we compute the tone of PBC communication using a bag-of-words approach and the financial dictionary developed by Loughran and McDonald (LM) (2011). We rely on a bag-of-words like method to quantify tone to avoid any downside from using the data twice, i.e., from training an algorithm that is applied to the same speeches such as in a support-vector machine approach. Dividing the sample into a training with predefined classes8 and a test would reduce the sample that we have in the empirical analysis (N=96). Moreover, as emphasized by [START_REF] Cambria | Affective computing and sentiment analysis[END_REF], statistical text classifiers provide relevant results only when given a sufficiently large text input. Therefore, we exploit prior knowledge in the form of LM dictionary to measure the tone of speeches.9 The LM dictionary is designed to fit financial and economic documents (see, e.g., [START_REF] Gurun | Don't believe the hype: Local media slant, local advertising, and firm value[END_REF][START_REF] Gurun | Don't believe the hype: Local media slant, local advertising, and firm value[END_REF][START_REF] Hillert | Media makes momentum[END_REF] and has proven to be relevant in the context of central bank communication [START_REF] Hansen | Shocking language: Understanding the macroeconomic effects of central bank communication[END_REF]. Furthermore, the use of the LM dictionary to measure tone has many advantages. First, researcher subjectivity is avoided. Second, since we use a computer program to determine the frequency of single words, the method scales to large samples. Third, the LM list is a well established dictionary used in finance and in other contexts as well (for a survey, see [START_REF] Loughran | Textual Analysis in Finance and Accounting: A Survey[END_REF]. Finally, since the LM dictionary is publicly available, it is easy to replicate this analysis. Many papers use this approach, i.e. the use of a dictionary to count specific words, to measure the tone of central bank communication (like e.g., [START_REF] Schmeling | Does central bank tone move asset prices?[END_REF][START_REF] Schmeling | Does central bank tone move asset prices?[END_REF][START_REF] Hubert | Central Bank Sentiment and Policy Expectations[END_REF][START_REF] Hubert | Central Bank Sentiment and Policy Expectations[END_REF]. Therefore, we use the LM dictionary to identify words that can be categorized as negative in economic and financial contexts. 10 We only use negative words because the usefulness of positive words to measure tone is limited since they can be negated. The paragraph below presents an excerpt of a speech made by Zhou Xiaochuan, the previous governor of the PBC on December 02, 2004. 11 We highlight in bold the words that convey a negative tone according to the LM dictionary. "There are many underlying reasons for financial risks. First, the rapid global economic, technological and financial development has made it difficult to address new problems with existing theories and experiences. Among these are the uncertainties in financial stability.

Second, in the transition from planned to market economy, some aspects of institution building is still in a vague, non-planned and non-market, or conflicting stage. Third, reality has proved that all kinds of problems in the economy are reflected in the workings of the financial system, which was particularly evident during the Asian financial crisis. Financial risks, if not addressed in a timely manner, could continue to grow and develop into economic and financial crisis."

We count the number of negative words in each speech and compute the ratio of the number of negative words, N , to the total number of words, T , N/T . On average, we find that the ratio of negative words to total words is 2.5%, while the maximum and minimum values are 7.4% and 0.84%, respectively. The tone of PBC speech delivered at time t, τ t , is defined as

τ t = 1 -N t /T t (1)
A lower value of τ t reflects more negative PBC tone and a higher values implies more positive tone. In the estimation procedure, we use change in tone, δτ t , measured as the first difference in τ t between two subsequent speeches. Hence, we interpret increase in δτ t as tone becoming more positive and decrease in δτ t as tone becoming more negative. We find that the tone increases in 52 speeches while it decreases in 48 speeches. Figure 2 below shows the evolution of δτ t over the full sample period.

II.2 Stock Market Index

To explore the effect of PBC communication on Chinese stock market, we use several daily data related to stock index. First, we use (i) an index that tracks the daily price performance of all A-shares that are restricted to local investors and qualified institutional foreign investors (SHASHR), (ii) the Shanghai Stock Exchange Composite Index (SHCOMP) which tracks the daily price performance of all A-shares and B-shares listed on the Shanghai Stock Exchange, (iii) an index consisting of the 50 most representative stocks from Shanghai security market (SSE50A) and (iv) the Shanghai Stock Exchange 180 A-Share Index which tracks the performance of the 180 most representative A-share stocks (SSE180A). Second, we use the Shenzhen Composite Index (SZCOMP) which shows the stock performance of all the A-share and B-share lists on the Shenzhen Stock Exchange.

II.3 Control variables

To test whether the tone of PBC communication has a significant impact on stock price beyond the economic and financial conditions, we use data related to PBC's policy action, macroeconomic fundamentals, external factors, supply shock, markets' volatility, consumer and business confidence and economic uncertainty as control variables.

PBC policy action. We use the one-year policy lending rate for financial institutions (Rate) as proxy for PBC policy rate decisions. Macroeconomic fundamentals. We use the yearly change of the Gross Domestic Product (GDP), the urban registered unemployment rate (Unemp), the annual change of the Consumer Price Index (CPI) and the year-over-year change of the industrial production index (IPI) to control for macroeconomic fundamentals. Moreover, we use oil price (Oil) to control for supply shock. External factors. Following [START_REF] Belke | Bond Yield Spillovers from Major Advanced Economies to Emerging Asia[END_REF][START_REF] Belke | On the Exposure of the BRIC Countries to Global Economic Shocks[END_REF] who find that the world trade and the financial spillovers from developed economies, such as the US and the euro area, have an impact on Chinese economic and financial conditions, we introduce the following external factors in the estimation procedure: the World Trade Index (WTI) and the US and the euro area 10-year government bond yields (US10Y and Euro10Y). Markets' volatility. To control for foreign financial stress, we use the emerging markets (excluding China) volatility indexes of bond (Vol. bond) and stock markets (Vol. stock). Confidence. We use the consumer confidence index (Cons. conf.) and the entrepreneurs' confidence index (Ent. conf.) to control for confidence. Economic Uncertainty. Finally, we use the Economic Policy Uncertainty (EPU) index developed by [START_REF] Baker | Measuring economic policy uncertainty[END_REF] to control for economic uncertainty in China. The EPU index is constructed based on newspaper articles regarding policy uncertainty. [START_REF] Baker | Measuring economic policy uncertainty[END_REF] count the number of articles published in the South China Morning Post using the terms "uncertain" or "uncertainty", "economic" or "economy", and scale the EPU count by a measure of the number of articles in the same newspaper and month.

The sources of the data are Bloomberg, the China National Bureau of Statistics and the PBC. If the data are not available at a daily frequency (such as for the GDP for instance), we use the last available data. We check the presence of unit root using the Augmented Dickey-Fuller (ADF) and the Phillips-Perron (PP) tests. We find that the null hypothesis cannot be rejected for GDP, oil price, the volatility index of bond market, the entrepreneurs' confidence index and the US and the euro area 10-year government bond yields. We use the first-difference of these variables in the estimation procedure. Moreover, the inclusion of many different explanatory variables might give rise to multicollinearity problems. We calculate the variance inflation factors (VIFs) for all models. In all cases, all VIFs are well below the rule of thumb threshold of 10. Table 7 in the appendix provides the summary statistics of the data.

III Econometric Setup

The empirical analysis follows the methodology of [START_REF] Schmeling | Does central bank tone move asset prices?[END_REF]. We explore how changes in the tone of PBC communication affect stock price. For that purpose, we need to compute stock price changes around the PBC speeches. The key idea is that any price reaction in a short time window is likely to be caused by the speech.

Since the set of policy targets of the PBC not only contains the common price stability and output gap, but also contains the stability of financial market, the release of PBC speech itself may reflect the central bank intention to manage the market expectation or to guide the market reaction when it is in trouble. For instance, a positive change of tone may reflect the PBC reaction to the stock market disturbances. As a result, after a bad shock, the stock market may have positive reaction to PBC speech with the expectation of government intervention. This to some extent reflects the fact that PBC speeches act as a policy tool to guide the market reaction.

So, to mitigate the endogeneity issue, we control for the aggregate factors that potentially cause the omitted variable bias.

To evaluate the immediate impact of PBC communication on stock price at day t, we compute the one-day stock price using the closing price of the day preceding the speech and the day on which the speech takes place. We denote the speech-day return by r t . We estimate r t on measure of tone change, δτ t , as follows

r t = α + βδτ t + γX t + t (2)
where r t represents a stock price with t specifying the day of the speech. α is a constant, β captures the effect of change of the tone of PBC communication, measured by δτ t , and X t is the vector of control variables. The error term, t , represents any other pricing factors affecting the financial variable, such as revisions of the implicit short-term interest rate, term premia, risk premia and all other possible asset-specific value drivers.

IV Tone of PBC Communication and Stock Market Reaction

In this section, we highlight a significant relationship between the tone of PBC communication and stock price in China. To provide evidence that the tone of PBC speeches contains additional information for stock price beyond the economic and financial conditions, we estimate (2) with and without the set of control variables, X t . Table 1 below shows the estimated results of (2)

for the period 2003M01-2010M10. 1 shows that change of the tone of PBC speeches has a statistically significant impact on stock price. Hence, positive (negative) change of the tone is associated with higher (lower) stock price in the Shanghai market, the Shenzhen market and for the 50 most representative stocks from the Shanghai security market. We find a significantly positive coefficient comprised between 0.7 and 1.1. In economic terms, a one standard deviation increase (decrease) in tone change, where σ[δτ t ]=0.38, is associated with higher (lower) return of 0.26% for the SHASHR and the SHCOMP, while the increase is around 0.35% for the SZCOMP. When we include the control variables, the effect of tone change on stock price is higher, that is, a one standard deviation increase is positively related to the SHASHR (SHCOMP) by 0.4% and by 0.44% for the SZCOMP. Concerning the 50 most representative stocks in the Shanghai market, a one standard deviation increase (decrease) in δτ increases (decreases) the index by 0.14%. Regarding the control variables, the results indicate that PBC policy action (euro area 10-year government bond yield), is positively and significantly related to the 180 (50) most representative A-share stocks in the Shanghai Stock Exchange. This is in accordance with Tillmann (2016) and Chen et al. ( 2014) who find that asset price movements in China can be significantly affected by financial and monetary conditions in advanced economies.

All in all, these results show a significant relationship between tone changes and stock price that is robust to controlling for economic and financial conditions. This suggests that PBC tone contains price-relevant information for Chinese stock market beyond the information contained in the set of control variables. According to Hubert and Labondance (2017), the significant impact of tone might be explained by the fact that tone could work as a coordinating device of higher-order private beliefs. An alternative explanation suggested by [START_REF] Schmeling | Does central bank tone move asset prices?[END_REF] is that tone affects asset prices through a risk-based channel of monetary policy, such as in [START_REF] Bernanke | What explains the stock market's reaction to Federal Reserve policy?[END_REF].

V Extensions

In this section, we propose additional extensions. First, we test the persistence of the effect of PBC tone on stock price, second, we differentiate the impact of positive and negative changes of the tone on stock price and third, we use an alternative indicator measuring the stance of PBC monetary policy. We find that PBC communication does not have a persistent effect on stock price and that positive changes of the tone affect significantly stock price, while this is not the case for negative changes. Finally, the tone of PBC communication has a positive and significant impact on stock price even when controlling for all the monetary policy instruments implemented by the PBC.

V.1 The Persistent Effect of the Tone of PBC Communication

We investigate the effect of PBC tone on stock price beyond the speech-day. We compute cumulative stock price over n days (starting with the speech-day) and define them as r t,n . For n = 2, r t,2 corresponds to the return one day after the speech and for n = 5, r t,5 specifies cumulative stock price from the day preceding the speech-day up to five trading days after the speech-day. The estimation procedure takes the following form.

r t,n = α + β n δτ t + γ n X t,n + t,n (3)
where r t,n is the cumulative stock price over n days (with 2 ≤ n ≤ 5) after the speech made at date t. The rest of the right-hand side variables are similar to those of (2). Table 2 below presents the results of the estimation for the period 2003M01-2010M10. To save some space, we do not show the results related to the control variables, X t,n , but only those of the persistent effect of PBC tone, τ t , with and without the control variables. Table 4 shows that even when controlling for all the monetary policy instruments used by the PBC through the sample period, change of the tone of PBC communication still has a positive and significant impact on stock prices indexed in Shanghai and Shenzhen, although it is significant at the 10% level only for stocks in Shenzhen. Hence, these findings reveal that PBC communication conveys relevant information for stock market beyond all the different monetary policy instruments implemented by the the central bank.

VI Robustness Tests

VI.1 Endogeneity

A central bank may choose to communicate at a particular time because of a sudden change in the economic or financial outlooks. In this case, asset prices will be more volatile on communication days, but not necessarily because of central banks statement [START_REF] Reeves | Do financial markets react to Bank of England communication?[END_REF]. To tackle this issue, we estimate (2) using the two-step Generalized Method of Moments (GMM)

introduced by [START_REF] Hansen | Large sample properties of generalized method of moments estimators[END_REF]. The GMM uses the orthogonality conditions to allow for efficient estimation in the presence of heteroskedasticity of unknown form. Regarding the instruments, we use a constant and the lagged value of the explained and the explanatory variables. Finally, we test for the validity of the instruments using a standard J -test for the validity of the overidentifying restrictions. We find similar results as in table 1, 13 that is, the parameter β is positive and significant at the 5% level for stock prices related to the SHASHR, the SHCOMP and the SSE50A while it is positive and significant at the 10% level for the SZCOMP. Moreover, the null hypothesis that the over-identifying restrictions are valid cannot be rejected in all models. These results show that even when addressing the reverse causality issue in the empirical analysis, the tone of PBC speeches still has a positive and significant impact on stock price in China.

VI.2 Parameter Restrictions

The inclusion of many control variables may lead to a change in the relation between the tone of PBC communication and stock price, hence, we test various linear restrictions using the F-test to check the robustness of this relationship. We consider three types of parameter restrictions: exclusion restriction, model significance and other linear restrictions.

Exclusion restriction: We test whether the main independent variable, δτ t , has no partial effect on the dependent variable, r t H 0 : β = 0

H 1 : β = 0
The F-test shows that the null hypothesis of no partial effect is rejected for all models except those that have the SSE50A and the SSE180A as dependent variable.

Model significance: We test the global significance of the different models estimated in the empirical analysis H 0 : β = γ 1 = γ 2 = ... = γ 14 = 0

H 1 : β = γ 1 = γ 2 = ... = γ 14 = 0
According to the F-test, the null hypothesis of no global significance is rejected for all models.

13 Results available upon request.

and the SZCOMP, while after the crisis, it is the SSE50A and the SSE180A that are mostly affected by the tone of PBC communication. Nevertheless, these results should be taken with caution since the number of observations corresponding to the post-crisis period is 30. Finally, once we use the AIC and the BIC to estimate the "best" model,14 the tone of PBC communication is positively and significantly associated to the SHASHR, the SHCOMP and the SZCOMP at the 1 level%.

VII Conclusion

Using textual data to model the financial market dynamics has been very popular these last years (for a survey of the most recent textual analysis techniques, see [START_REF] Xing | Natural language based financial forecasting: a survey[END_REF][START_REF] Xing | Sentiment-aware volatility forecasting[END_REF]).

This articles aims to contribute to this literature by testing the impact of PBC communication on stock price. For that purpose, we first rely on a computational linguistic approach and the [START_REF] Loughran | When is a liability not a liability? Textual analysis, dictionaries, and 10Ks[END_REF] financial dictionary to compute the tone conveyed through PBC speeches. As a second step, we use a high frequency methodology to determine the impact of PBC tone on stock market. The results reveal that positive changes of the tone affect positively stock price in the Shanghai and the Shenzhen stocks markets. The significant effect of tone on stock price is robust to a set of control variables. Furthermore, we find that PBC communication does not have a persistent effect on stock price and that the tone of PBC communication still has a positive and significant impact on stock price even when controlling for all the monetary policy instruments implemented by the central bank. The findings of this paper highlight that PBC communication affects stock price and matters as a policy tool to shape market expectations.

Hence, as China moves toward a flexible exchange rate regime and more financial liberalization, better communication and more transparency, including through forward guidance, can have important benefits to improve the effectiveness of PBC's monetary policy.

  Figure 1 Number of speeches per year

Figure 2

 2 Figure 2Change of the tone of PBC speeches

  Table 7 in the Appendix provides detailed statistics of δτ t .

Table 1 :

 1 PBC Tone and Stock Price (2003M01-2010M10)

		SHASHR	SHCOMP	SZCOMP	SSE50A	SSE180A
	α	0.11	1.005	0.11	0.99	0.08	3.26	0.005	5.17	0.06	2.7
		[0.14]	[15.7]	[0.14]	[15.6]	[0.16]	[18.27]	[0.16]	[28.6]	[0.16]	[15.2]
	δτ t	0.67** 1.01** 0.66** 1.009*** 0.89** 1.14** 0.47*	0.35	0.05	-0.26
		[0.31]	[0.36]	[0.31]	[0.36]	[0.38]	[0.43]	[0.28]	[0.33]	[0.55]	[0.36]
	Rate		0.82		0.82		0.51		1.26		1.54**
			[0.57]		[0.57]		[0.64]		[0.79]		[0.63]
	GDP		0.008		0.006		0.07		0.10		-0.06
			[0.29]		[0.29]		[0.35]		[0.21]		[0.27]
	CPI		-0.01		-0.01		0.002		0.02		0.04
			[0.05]		[0.05]		[0.06]		[0.04]		[0.05]
	IPI		0.003		0.003		0.005		0.0009		-0.004
			[0.004]		[0.004]		[0.006]		[0.002]		[0.004]
	Unemp		1.97		1.97		1.65		-0.23		2.69

Table 2 :

 2 PBC Tone and Cumulative Stock Price (2003M01-2010M10) An Alternative Measure of PBC Monetary Policy Stance It is well known that the monetary policy instruments used by the PBC have varied over time. As an illustration, Xiong (2012) suggests that the credit plan was used as the main policy instrument during the 1990s but that it was abandoned in 1998 and replaced by central bank refinancing to the commercial banks. Then, from 2000s onward, open market operations began to play an important role. An additional feature of the PBC is that it uses different instruments to achieve a similar objective. For instance, during the years 2006-2007, the reserve requirements and the open market operations were both used to absorb excessive liquidity while 2008 and 2011, the PBC announced contractionary monetary policy and undertook a series of tightening measures to curb inflation. Consequently, the monetary policy instruments used by the PBC are different in nature and are not used in the same frequency nor magnitude. Hence, it is importantto embed these different policy instruments into a single index reflecting the overall monetary policy stance of the PBC. For that purpose, we use the policy stance index constructed by[START_REF] Xiong | Measuring the monetary policy stance of the People's bank of china: An ordered probit analysis[END_REF] between 1986Q4 and 2010Q3. The index reflects the movements of all the important monetary policy instruments used by the PBC and captures as much information on monetary policy actions as possible (see table 8 and figure3in the appendix). 12 We replace the control variable related to PBC policy action by the policy stance index developed by[START_REF] Xiong | Measuring the monetary policy stance of the People's bank of china: An ordered probit analysis[END_REF] in the baseline estimation (2) and re-estimate it. Table4below shows the results of the estimation for the period 2003M01-2010M10. To save some space, we only show the results related to the effect of the changes of PBC tone on stock price, i.e. the parameter β.

		Without control variables	With control variables
	Day	α	δτt	R 2	Obs.	α	δτt	R 2	Obs.
	n=2	0.03	0.7	0.01	87	44.9**	1.06** 0.39	81
	SHASHR

Table 4 :

 4 PBC Tone and Stock Price (2003M01-2010M10)Dependent variable: rt. Estimates are obtained using Newey-West standard errors. *, **, *** denote significance at the 10%, 5% level and 1% level, respectively. Standard errors between brackets.

		α	δτt	R 2	Obs.
	SHASHR	-8.72	0.86** 0.24	81
		[15.6]	[0.4]
	SHCOMP	-8.65	0.86** 0.42	81
		[15.5]	[0.4]
	SZCOMP	-10.64	0.98*	0.28	81
		[16.6]	[0.49]
	SSE50A	34.15	0.32	0.25	73
		[23.1]	[0.32]
	SSE180A	24.9	-0.24	0.23	78
		[20.7]	[0.4]

Requests for monetary policy changes can be submitted to the State Council not only by the PBC but also by other ministries or agencies.

From the day before, close of business, to the day of the speech, close of business.

http://www.pbc.gov.cn/en/3688110/3688175/index.html.

These predefined classes would associate a speech with a positive or a negative tone.

[START_REF] Li | Learning word representations for sentiment analysis[END_REF] provides examples of various types of prior knowledge that can be used to perform sentiment analysis.

The LM dictionary lists 2335 words to describe the negative tone. Words such as aggravate, anomaly, bankrupt, collapse, collusion or complaints are used to describe negative tone in economic and financial contexts.

Improve legal system and financial ecology. Speech by Mr Zhou Xiaochuan, Governor of the People's Bank of China, at the "Forum of 50 Chinese Economists", Beijing, 2 December 2004.

For more details on the construction of the monetary policy stance index, seeXiong (p.516, 2012).

The "best" model according to the AIC and the BIC includes the following control variables: the PBC policy rate, the GDP, the CPI, the IPI, the unemployment rate, oil price, the volatility of bond market, the consumer confidence index, the 10-year US government bond yield and the world trade index.

of the Money, Macro & Finance Research Group and the CEREC " for helpful comments on earlier versions of the article. I also thank seminar participants at the Bank of Finland Institute for Economies in Transition (BOFIT), the

Table 2 shows that the slope coefficient of tone changes is significantly positive, at the 5% level, during the time window that captures PBC speech the day after, r t,2 , for all stock prices except 12 the SSE50A, but is not significant during later time windows, i.e. when n > 2. Hence, these results suggest that PBC communication does not have a persistent effect on stock price two days after the speech as shown by the non-significant value of the parameter β n when n > 2.

V.2 Asymmetric Reaction to Tone Changes

To check whether stock price react asymmetrically to positive and negative changes of the tone of PBC communication. We estimate the following model

where

) takes the value 1 when δτ > 0 (δτ < 0), and 0 otherwise. The rest of the left-hand side and right-hand side variables are similar to (2). Table 3 below shows the estimated results of (4). When we consider positive and negative changes of the tone in the estimation procedure, we find that positive changes drive stock markets in Shanghai and Shenzhen upward, as shown by the significant and positive parameter λ, while negative changes do not affect stock price. Hence, the results show that stock markets are responsive to positive changes of the tone but do not react when the tone becomes more negative. This one-side impact suggests that the PBC is able to stabilize the stock market through its communication policy. Interestingly, Tang et al.

(2013) find similar evidences for the Shanghai stock market, that is, market returns climb up in the Shanghai stock market after a friendly policy, i.e. a decrease of the rate. For the US stock market, [START_REF] Frank | How does the stock market absorb shocks?[END_REF] show that markets overreact to good news and underreact to bad news. According to [START_REF] Chan | Stock price reaction to news and no-news: drift and reversal after headlines[END_REF], this might be explained by the fact that investors react slowly to bad news.

Testing other linear restrictions: We consider linear restriction by imposing a specific value to the parameter related to the change of tone of PBC communication, δτ t , such as

The F-test shows that the null hypothesis cannot be rejected for all models except those that have the SSE50A and the SSE180A as dependent variable.

These parameter restriction tests show that even when including the set of control variables in the estimation procedure, the relationship between the tone of PBC communication and stock price remains robust.

Finally, to check whether there is a long-run relationship between tone and stock price (hysteresis effect), we make unit root tests (using the ADF and the PP tests) on these variables and find that the null hypothesis of the presence of a unit root can be rejected. This shows that there is no long-run relationship between tone and stock price.

VI.3 Functional Form

It is important to distinguish between different specifications which can be examined in the framework of a liner regression from those which cannot. Therefore, we check for functional forms by testing (i) whether the tone of PBC communication has a non-linear effect on stock price and (ii) whether the effect of tone on stock price is conditional on the evolution of the other control variables. Hence, we include the squared value of the change of tone, δτ t , and several interaction terms relating change of tone with the control variables in the estimation procedure

(2).

The results indicate that change of tone does not have a non-linear effect on stock price given that the squared value of δτ t is not significant in all models. Furthermore, we find that higher oil price significantly reduce the impact of the tone of PBC communication on stock price corresponding to the SHASHR, the SHCOMP and the SSE50A.

VI.4 Further Robustness Tests

We make several robustness tests to exploit all usual possibilities in the framework of our analysis.

We split the sample according to the identification of a structural break. We identify a break on september 2008. Interestingly, this date corresponds to the collapse of Lehman Brothers and the start of the Global Financial Crisis (GFC). Hence, we distinguish the pre-crisis period (2003M01-2008M08) from the post-crisis one (2008M09-2010M10). We also use the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) to estimate the "best" model in term of relative quality.

When we split the sample before and after the start of the GFC, we find that before the crisis, the tone of PBC communication mainly affectings stock price related to the SHASHR, the SHCOMP [START_REF] Xiong | Measuring the monetary policy stance of the People's bank of china: An ordered probit analysis[END_REF] The values -1, 0, and 1 indicate an expansionary change, no change, and a contractionary change in the policy stance, respectively.

VIII Appendix


MD Hélène Vallet
email: helene.vallet@gmail.com

Laura Moïsi

Caroline Thomas

Bertrand Guidet

Ariane Boumendil

Acute critically ill elderly patients: what about long term caregiver burden?

Keywords: acute critical illness, older patients, caregiver burden, Zarit

Purpose: Acute critical illness induce a high caregivers burden in the young population, however data in the older population are lacking. The objectives of this study were to evaluate caregiver burden in a critically ill old population and to assess factors associated with mild to severe burden level.

Materials and methods:

All patients from two participating centers of the ICE-CUB 2 trial were included in the study. Inclusion criteria were an age≥75, at least one critical condition and preserved functional status. The primary endpoint was a Zarit Burden Interview (ZBI) ≥ 21 at 6 months.

Results:

One hundred ninety-one patients (median age 86 [81-89] years) were included. Median caregiver ZBI at 6 months was 13 . In the multivariate analysis, factors significantly associated with moderate to severe burden were the 6-month ADL decrease (OR: 1.3, p = 0.049) and the 6-month mental component of the quality of life score (OR: 0.94, p = 0.0009). In contrast, age, ICU admission and length of hospital stay were not associated with moderate to severe load.

Conclusion:

In our study, functional status and mental health at 6 months were associated with mild to severe burden unlike age and admission in ICU.

Introduction

The proportion of patients older than 75 years is steadily growing worldwide. Logically, this affects Intensive Care Unit (ICU) admission rates [START_REF] Vincent | Comparison of European ICU patients in 2012 (ICON) versus 2002 (SOAP)[END_REF], with a fast increase in admission of older adults to ICUs these last years [START_REF] Flaatten | The status of intensive care medicine research and a future agenda for very old patients in the ICU[END_REF]. The high mortality rate and potential risk of loss of autonomy in critically ill older patients raises the question of the benefits of intensive care in this population. For the intensivist, selecting "good" candidates both able to survive an ICU and hospital stay and to recover their previous functional autonomy is challenging [START_REF] Guidet | Should this elderly patient be admitted to the ICU?[END_REF]. Several studies have addressed ICU triage and identification of admission criteria [START_REF] Garrouste-Orgeas | Decision-making process, outcome, and 1-year quality of life of octogenarians referred for intensive care unit admission[END_REF][START_REF] Andersen | Long-Term Outcomes After ICU Admission Triage in Octogenarians[END_REF][START_REF] Garrouste-Orgeas | Selection of intensive care unit admission criteria for patients aged 80 years and over and compliance of emergency and intensive care unit physicians with the selected criteria: An observational, multicenter, prospective study[END_REF]. In the ICE-CUB1 trial, age, active cancer, a lower functional autonomy, unknown hospitalization status and living arrangements were associated with a lower intensive care unit referral by emergency physicians [START_REF] Garrouste-Orgeas | Selection of intensive care unit admission criteria for patients aged 80 years and over and compliance of emergency and intensive care unit physicians with the selected criteria: An observational, multicenter, prospective study[END_REF].

Furthermore, there was a high variation of ICU eligibility rate according to centers, independently of patient and hospital characteristics [START_REF] Boumendil | Variability of intensive care admission decisions for the very elderly[END_REF].

One reason for ICU admission limitations could be fear of a high burden for the patients' relatives after hospital discharge. Several studies in younger populations report anxiety, depressive symptoms, poor sleep quality and post-traumatic stress disorder in family caregivers of ICU survivors [START_REF] Cameron | One-Year Outcomes in Caregivers of Critically Ill Patients[END_REF][START_REF] Choi | Sleep in family caregivers of ICU survivors for two months post-ICU discharge[END_REF][START_REF] Mcpeake | Caregiver strain following critical care discharge: An exploratory evaluation[END_REF]. In the older population, no data are available in the ICU context, but some studies show that high caregiver burden is strongly associated with dementia, neuropsychiatric symptoms, delirium and decrease of patient's functional autonomy [START_REF] Bonin-Guillaume | Predictive factors for early unplanned rehospitalization of older adults after an ED visit: role of the caregiver burden[END_REF][START_REF] Elmståhl | The association between medical diagnosis and caregiver burden: a cross-sectional study of recipients of informal support and caregivers from the general population study "Good Aging in Skåne", Sweden[END_REF][START_REF] Shankar | Burden in caregivers of cognitively impaired elderly adults at time of hospitalization: a cross-sectional analysis[END_REF].

The objectives of this study were to evaluate caregiver burden in a critically ill older population 6 months after an acute medical event and to assess factors associated with mild to severe burden level.

Methods

All patients from two of the centers participating in the ICE-CUB 2 trial (clinical trial gouv NCT 01508819) were included in this study. The ICE-CUB 2 trial was a large cluster-randomized clinical trial whose aim was to determine whether a recommendation for systematic ICU admission in critically ill older patients reduced six-month mortality, as compared to usual practices (ICE-CUB 2). This sub-study was planned a priori, the study design is described in detail elsewhere [START_REF] Boumendil | Designing and conducting a cluster-randomized trial of ICU admission for the elderly patients: the ICE-CUB 2 study[END_REF][START_REF] Guidet | Effect of Systematic Intensive Care Unit Triage on Long-term Mortality Among Critically Ill Elderly Patients in France: A Randomized Clinical Trial[END_REF] and the protocol is available online [START_REF] Guidet | Effect of Systematic Intensive Care Unit Triage on Long-term Mortality Among Critically Ill Elderly Patients in France: A Randomized Clinical Trial[END_REF]. Briefly, in this cluster-randomized clinical trial, healthcare centers were randomly assigned either to the intervention group (the systematic-strategy group) or the control group. In healthcare centers assigned to the systematic-strategy group, a program promoting systematic ICU admission was implemented. In healthcare centers assigned to the control group, there was no specific recommendation regarding the ICU triage process (standard-strategy group). In both groups, the final decision for admission or not in ICU was made by the physicians at bedside.

Participant Selection

All patients were included in the ICE-CUB 2 clinical trial. Inclusion criteria were an age≥75 years, at least one of the pre-established critical conditions [START_REF] Guidet | Effect of Systematic Intensive Care Unit Triage on Long-term Mortality Among Critically Ill Elderly Patients in France: A Randomized Clinical Trial[END_REF], a preserved functional status as assessed by an Index of Independence in Activities of Daily Living (ADL) ≥4 (0=totally dependent, 6=independent) or an unknown ADL score, a preserved nutritional status (defined as the absence of cachexia, subjectively assessed by the physicians at bedside) and the absence of active cancer. Exclusion criteria were an emergency department stay over 24 hours, a secondary referral to the emergency department or refusal to participate. Patients in whom cancer was diagnosed after inclusion remained in the statistical analysis.

In two centers (one in each group) the Zarit Burden Interview was evaluated at 6 months. Only in caregivers with completed Zarit Burden interview (ZBI) related to patient data were used.

The ZBI is a 22-item questionnaire in which caregivers self-assess the level of burden [START_REF] Zarit | Relatives of the impaired elderly: correlates of feelings of burden[END_REF]. Each item of the questionnaire is a statement which the caregiver is asked to endorse using a 5-point scale. Response options range from 0 (Never) to 4 (Nearly Always). The score ranges from 0 to 88. The interpretation of the score is the following: from 0 to 20, there is no or a low burden; from 21 to 40 the burden is mild to moderate ; from 41 to 60 the burden is moderate to severe; and above 61 the burden is severe.

Statistical Analysis

Baseline characteristics of patients were analyzed as frequencies and percentages for categorical variables and as medians and interquartile ranges (IQR) for continuous variables. Bivariable associations were evaluated with t-test for continuous variables and Chi-square or Fisher exact test for categorical variables, as appropriate. Variables for all adjusted analyses were: age, illness severity, initial clinical diagnosis, seniority of the emergency physician, time of ICU admission, baseline functional status, place of residence and type of home support. Caregiver burden was categorized as light or moderate vs no or low and analyzed as a binary outcome by means of a logistic regression model. All analyses were performed at a two-sided alpha level of 5%. A pvalue of less than 0.05 was considered to indicate statistical significance. All analyses were performed (AB) with R software, version 3.2.2 (R Foundation for Statistical Computing).

Results

Between January 2012 and April 2015, a total of 3,037 patients were enrolled in the ICE-CUB2 clinical trial; 1,519 patients in 11 healthcare centers allocated to the systematic-strategy group and 1,518 patients in 13 healthcare centers allocated to the standard-strategy group.

N= 191 caregivers (from 191 patients) were willing to complete the Zarit Burden Interview questionnaire (N=115 in the control group and N=76 in the systematicstrategy group). . ZBI were completed without missing answers for 148 caregivers (n=91 in the control group and n=57 in the systematic-strategy group). Missing answers were then imputed to 2 for each missing value and the score was computed for all 191 patients, the median being 13 .

Baseline characteristics of the patients for whom caregiver burden was assessed are presented in Table 1. Although the median age was 86 years, functional autonomy of included patients at Emergency Department (ED) visit was good (ADL 6 (5.5-6)). Main diagnosis were acute respiratory failure (n=69; 36.1%) and shock (n=37; 19.4%). Fifty three percent of patients were admitted to the ICU and 37.8% of them required organ support. A large majority of patients and family expressed no opinion regarding ICU admission (n=150; 78.5%). At 6 months, the median ADL scale decreased by 0.5 points and 13.8% of patients were admitted to a nursing home.

Compared to patients with no or low caregiver burden, patients with mild to severe caregiver burden at 6 months had stayed in the hospital longer, required more invasive procedures in the ICU, were less self-sufficient at 6 months, and had a lower quality of life.

Furthermore, caregiver burden was not significantly different between groups (systematic-strategy vs control) (p=0.61) and between admission location (ICU vs not) (p=0.68) (Figure 1)

Factors associated with mild to severe caregiver burden

In the univariate analysis, male sex, length of hospital stay, loss of functional autonomy, and lower quality of life at 6 months were associated with mild to severe burden. Age, ICU admission and all factors associated with high level burden with a pvalue <0.2 in univariate analysis were included in a regression logistic model (Table 2). In the multivariate analysis, decrease in ADL scale was significantly associated with mild to severe burden (OR: 1.3 [1-1.68], p=0.049) and a higher mental SF12 scale was negatively correlate with a mild to severe burden (OR: 0.94 [0.89-0.98], p=0.009).

Interestingly enough, age, admission to the ICU and length of hospital stay were not associated with mild to severe burden (OR: 0.84 [0.41-1.73], p=0.64; OR: 0.99 [0.93-1.06], p=0.85; OR: 1.02 [0.99-1.06], p=0.12 respectively).

Discussion

Our study focuses on caregiver burden 6 months after critical illness in the older population. We found that more than one third of caregivers suffer from mild to severe burden (ZBI ≥21). Patient factors associated with this burden are the loss of functional autonomy and lower mental health status 6 months after initial admission. Surprisingly, age, admission to the ICU and hospital length of stay were not associated with the severity of burden in the multivariate analysis.

In a younger population, Cameron et al. found that a high burden level was common for caregivers of critically ill patients more frequently than in our study (53% to 69% [START_REF] Mcpeake | Caregiver strain following critical care discharge: An exploratory evaluation[END_REF][START_REF] Comini | Impact of Clinical and Quality of Life Outcomes of Long-Stay ICU Survivors Recovering From Rehabilitation on Caregivers' Burden[END_REF] vs 37%). More than half of caregivers presented depressive symptoms initially, these symptoms decreasing partially with time [START_REF] Cameron | One-Year Outcomes in Caregivers of Critically Ill Patients[END_REF]. One explanation to the difference in burden perception could be age. Older patient caregivers (spouses) are often old themselves, and a younger age in caregivers is associated with more depressive symptoms [START_REF] Cameron | One-Year Outcomes in Caregivers of Critically Ill Patients[END_REF]. One could also wonder whether the caregiver's relationship to the patient impacts the level of burden, since caring for a spouse could be viewed by some as more natural than caring for a parent. In Cameron et al's study, 60% of caregivers where spouses, 6.7% were siblings, 14.7% were children of patients and 13.9% were parents of patients. Caregivers caring for their spouses had fewer depressive symptoms than others (mean difference in outcome -2.46, p<0.05) [START_REF] Cameron | One-Year Outcomes in Caregivers of Critically Ill Patients[END_REF]. Unfortunately, in our study, we were lacking data regarding caregiver status and so could not investigate this hypothesis.

In the older population, caregiver burden has been described in several situations. In Alzheimer's disease and other dementia, burden is associated with the severity of dementia [START_REF] Kamiya | Factors associated with increased caregivers' burden in several cognitive stages of Alzheimer's disease[END_REF], behavioral disorders and loss of functional autonomy [START_REF] Kamiya | Factors associated with increased caregivers' burden in several cognitive stages of Alzheimer's disease[END_REF][START_REF] Dauphinot | Risk factors of caregiver burden among patients with Alzheimer's disease or related disorders: a cross-sectional study[END_REF][START_REF] Conde-Sala | Three-year trajectories of caregiver burden in Alzheimer's disease[END_REF]. In other advanced illnesses such as cancer, congestive heart failure and chronic obstructive pulmonary disease, the main factor associated with burden is the need for help with activities of daily living [START_REF] Garlo | Burden in caregivers of older adults with advanced illness[END_REF]. In our study, patient's comorbidities are not reported notably dementia that could influence caregivers burden. Caregiver characteristics associated with a high burden level are being the only person in charge, living with the patient and being an adult child [START_REF] Conde-Sala | Three-year trajectories of caregiver burden in Alzheimer's disease[END_REF][START_REF] Mello J De | The determinants of informal caregivers' burden in the care of frail older persons: a dynamic and role-related perspective[END_REF]. ZBI is lower in our study as compared to a population of caregivers of patients with Alzheimers' disease (15 to 41 in the AD study vs 13 in ours) [START_REF] Kamiya | Factors associated with increased caregivers' burden in several cognitive stages of Alzheimer's disease[END_REF][START_REF] Conde-Sala | Three-year trajectories of caregiver burden in Alzheimer's disease[END_REF]. Loss of functional autonomy plays a central role in the perception of burden. Although mortality is high after an intensive care unit stay, survivor's functional autonomy in relatively decent.

Only 28% to 37% did not restore their previous functional autonomy, based on the ADL score measured at 3, 6 and 12 months [START_REF] Sacanella | Functional status and quality of life 12 months after discharge from a medical ICU in healthy elderly patients: a prospective observational study[END_REF][START_REF] Villa | Functional Status and Quality of Life in Elderly Intensive Care Unit Survivors[END_REF]. At 12 months, 50% of survival patients had recovered their previous ADL score, IALD and physical capacities [START_REF] Heyland | Recovery after critical illness in patients aged 80 years or older: a multi-center prospective observational cohort study[END_REF]. Thus, higher functional autonomy in patients after critical illness than in AD could partially explain a lower ZBI.

Our study included only unplanned patient since the inclusion took place in the emergency department. This strengthens the message since planned surgery are totally different from emergency admission [START_REF] Jung | A comparison of very old patients admitted to intensive care unit after acute versus elective surgery or intervention[END_REF] with less frail patients who are also the less dependent.

Conclusion/Implications:

In our study, functional status and mental health at 6 months were associated with mild to severe burden unlike age and admission in ICU. These results suggest that fear of inducing high caregiver burden shouldn't be an obstacle to the ICU admission of elderly patients. However, improving their long-term autonomy should be a priority as it plays a central role in the perception of burden. Furthermore, caregiver burden should be systematically evaluated during the initial geriatric assessment as well as during followup consultations, so as to better evaluate and prevent caregiver burnout [START_REF] Brown | Caregiver burden should be evaluated during geriatric assessment[END_REF].

LEGENDS:

  : H. Vallet, L. Moïsi, C. Thomas and A. Boumendil have declared that they have no conflict of interest. B. Guidet reports receipt of lecture fees from Griffols and LFB and grants from LFB without any interference with the present article.

Figure 1 :

 1 Figure 1: Comparison of ZBI between patients admitted in ICU or not (A) and between the Systematic ICU admission and the standard group (

Table 1 :

 1 patient's characteristics

Table 2 :

 2 Univariate and multivariate analysis of factors associated with mild to severe burden (ZARIT ≥ 21)

Table 1 : patients characteristics

 1 Emergency Department; SF: Short form. Missing value: a 163 b 17 c 93 d 7 e 3 f 24 g 2

	All patients (n=191)	mild to severe burden	No or little burden	P value
		(n=71)	(n=120)

Table 2 : Univariate and multivariate analysis of factors associated with mild to severe burden (ZARIT ≥ 21)

 2

	Univariate	Multivariate

Funding: ICE-CUB2 study was funded by the Programme Hospitalier de Recherche Clinique 2010 of the French Ministry of Health.

Data collection

The following data were collected: age, sex, ICU admission, SAPS III [START_REF] Moreno | SAPS 3--From evaluation of the patient to evaluation of the intensive care unit. Part 2: Development of a prognostic model for hospital mortality at ICU admission[END_REF], diagnosis at admission, invasive procedure used in ICU, ADL at admission and 6 months, SF-12 [START_REF] Gandek | Crossvalidation of item selection and scoring for the SF-12 Health Survey in nine countries: results from the IQOLA Project. International Quality of Life Assessment[END_REF] at 6 months, place of living at admission and 6 months, length of hospital stay, patient's and family's opinion about ICU admission.

Primary endpoint and objectives.

The primary endpoint was a ZBI ≥ 21 (mild to severe burden) at 6 months.

The primary objective was to identify factors associated with mild to severe burden (ZBI ≥ 21). Secondary objectives were ICU admission rate, in-hospital death, functional status at 6 months as assessed by the ADL scale, and quality of life at 6 months as assessed by the 12-item Short-Form (SF-12) Health Survey. For patients discharged alive, ZBI information was obtained via phone, from patient caregivers.

Author Contributions: HV, LM, CT, BG and AB contributed to the conception of the study. HV and AB analyzed the data. HV, LM, CT, BG and AB drafted the manuscript and contributed to the writing of the article.


Federica Calevro
email: federica.calevro@insa-lyon.fr

Denis Tagu
email: denis.tagu@inra.frpatrick.callaerts@kuleuven.be

Patrick Callaerts

Acyrthosiphon pisum

Keywords: Animalia PHYLUM, Arthropoda CLASS, Insecta ORDER, Hemiptera SUPERFAMILY, Aphididoidea FAMILY, Aphididae GENUS, Acyrthosiphon

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

SPECIES FACTS:

• A. pisum is a soft-bodied insect that alternates between parthenogenetic, viviparous reproduction and sexual oviparous reproduction. Sexual reproduction is initiated upon lengthening of nights and reduction of temperature. • It is a relatively large aphid (several millimeters in adults), readily reared on plants or on artificial medium in the laboratory.

• Aphids comprise different morphs (winged and non-winged), the occurrence of which is determined by population density and/or presence of danger.

• Aphids have a novel cell type, the bacteriocyte, that was initially assumed to simply house the endosymbiotic bacteria. However, recent data reveals a more prominent role in physiological plasticity by controlling nutritional needs when facing physiological or environmental constraints.

• A. pisum is readily tractable experimentally with genome editing methods becoming available.

FUN FACT ABOUT THE GENOME:

Novel genes are found with thus far unknown functions. These include BCRs (bacteriocyte cysteine-rich peptides) and SPs (Secreted Proteins), and a class of putative zinc finger containing transcription factors. It has been suggested that the BCRs may be related to the presence of endosymbionts while the Zn-finger TFs may play a role in phenotypic plasticity of aphids.

Resources i https://bipaa.genouest.org/is/aphidbase/

ACKNOWLEDGMENTS

Authors thank INRA, INSA-Lyon and KULeuven. PC was the recipient of an Invited Professor Grant of INSA-Lyon.

LITERATURE: