Exchange rate exposure and firm dynamics

This paper develops a heterogeneous firm-dynamics model to jointly study firms' currency debt composition and investment choices. In our model, foreign currency borrowing arises from a dynamic trade-o between exposure to currency risk and growth. The model endogenously generates selection of productive firms into foreign currency borrowing. Among them, firms with high marginal product of capital use foreign loans more intensively. We assess econometrically the model's predicted pattern of foreign currency borrowing using firm-level census data from the deregulation of these loans in Hungary, calibrate the model and quantify the aggregate impact of this financing. Our counterfactual exercises show that assessing the allocation of foreign loans across firms is critical to understand their aggregate consequences

Hormone profile in acute psychotic disorders: A cross-sectional comparison of serum hormone concentrations in treated and untreated male patients with schizophrenia

Background: Antipsychotic drugs for the treatment of schizophrenia provide effective treatment of psychotic symptoms but might lead to neuroendocrine abnormalities.Objective: the aim of this study was to assess hypothalamic-pituitary-gonadal (HPG) axis function by comparing serum hormone profiles of newly admitted patients with psychotic disorders who were receiving antipsychotic drugs with those who were antipsychotic-drug-free during the preceding 6 months.Methods: Adult male patients admitted during a 1-year period (December 1999 to December 2000) to I of 2 Brazilian public psychiatric inpatient units that provide care for severely ill patients were eligible for this cross-sectional study if they had a diagnosis of schizophrenia based on the criteria given in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and a score > 24 on the Brief Psychiatric Rating Scale. On the morning after admission, serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), prolactin, free testosterone (FT), and total testosterone (TT) were determined. A commercial laboratory provided the normal serum hormone concentrations of healthy Brazilian men in the same age range as that of the study patients.Results: Sixty-three adult male patients, aged 18 to 55, were included in the study. Forty-eight (76.2%) patients (mean [SD] age, 30.6 [8.9] years) were receiving antipsychotic drugs (treated). Fifteen (23.8%) patients (mean [SD] age, 36.5 [9.8] years) were antipsychotic-drug-free for 6 months before admission (untreated). the only significant between-group difference was for disease duration (treated, 7.6 [8.1] years vs untreated, 12.3 [9.7] years; P = 0.044). Treated patients were more likely to have higher dispersed serum hormone concentrations than the untreated patients. Serum concentration of FSH was numerically higher in the treated patients than in the untreated patients, although the difference was not statistically significant. Compared with the control group (1436 men and women for prolactin; 226 men for LH; 207 for FSH; 128 for TT; 128 for FT; and 128 for SHBG), patients in the treated group had significantly different mean [SD] serum concentrations of all hormones (treated vs control: prolactin, 24.3 [23.7] mu g/L vs 6.8 [0.12] mu g/L, P < 0.001; LH, 4.9 [3.4] U/L vs 3.3 [0.13] U/L, P = 0.001; FSH, 4.4 [3.9] U/L vs 3.0 [0.06] U/L, P = 0.025; TT, 17.5 [7.8] nmol/L vs 20.1 [1.64] nmol/L, P = 0.004; FT, 0.056 [0.08] nmol/L vs 0.06 [0.003] nmol/L, P < 0.001; and SHBG, 33.3 [18.9] nmol/L vs 48.4 [1.45] nmol/L, P = 0.002). Compared with the control group, patients in the untreated group had significantly different mean (SD) serum concentrations of all hormones except FSH and TT (untreated vs control: prolactin, 19.9 [12.8] mu g/L vs 6.8 [0.12] mu g/L, P = 0.001; LH, 6.0 [1.9] U/L vs 3.3 [0.13] U/L, P = 0.002; FT, 0.08 [0.04] nmol/L vs 0.06 [0.003] nmol/L, P = 0.001; and SHBG, 26.6 [11.6] nmol/L vs 48.4 [1.45] nmol/L, P < 0.001). No differences were found between the TT distribution curve of the control group and that of the untreated patients.Conclusion: This study supports further investigation of a potential difference in the HPG axis among treated and untreated patients with schizophrenia and those who do not have that condition.Universidade Federal de São Paulo, Dept Psychiat, São Paulo, BrazilBristol Myers Squibb Co, São Paulo, BrazilFed Univ Pelotas, Dept Psychiat, Pelotas, BrazilEli Lilly Brazil, São Paulo, BrazilPax Clin Psiquiatrica, Goiania, Go, BrazilUniv Fed Bahia, Dept Psychiat & Neurol, Salvador, BA, BrazilUniv Fed Bahia, Dept Pharmacol, Salvador, BA, BrazilUniversidade Federal de São Paulo, Dept Psychiat, São Paulo, BrazilWeb of Scienc

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

This is the final version of the article. Available from Wiley via the DOI in this record.Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs.This paper is a product of the European Union's Seventh Framework Programme AMAZALERT project (282664). The field data used in this study have been generated by the RAINFOR network, which has been supported by a Gordon and Betty Moore Foundation grant, the European Union's Seventh Framework Programme projects 283080, ‘GEOCARBON’; and 282664, ‘AMAZALERT’; ERC grant ‘Tropical Forests in the Changing Earth System’), and Natural Environment Research Council (NERC) Urgency, Consortium and Standard Grants ‘AMAZONICA’ (NE/F005806/1), ‘TROBIT’ (NE/D005590/1) and ‘Niche Evolution of South American Trees’ (NE/I028122/1). Additional data were included from the Tropical Ecology Assessment and Monitoring (TEAM) Network – a collaboration between Conservation International, the Missouri Botanical Garden, the Smithsonian Institution and the Wildlife Conservation Society, and partly funded by these institutions, the Gordon and Betty Moore Foundation, and other donors. Fieldwork was also partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico of Brazil (CNPq), project Programa de Pesquisas Ecológicas de Longa Duração (PELD-403725/2012-7). A.R. acknowledges funding from the Helmholtz Alliance ‘Remote Sensing and Earth System Dynamics’; L.P., M.P.C. E.A. and M.T. are partially funded by the EU FP7 project ‘ROBIN’ (283093), with co-funding for E.A. from the Dutch Ministry of Economic Affairs (KB-14-003-030); B.C. [was supported in part by the US DOE (BER) NGEE-Tropics project (subcontract to LANL). O.L.P. is supported by an ERC Advanced Grant and is a Royal Society-Wolfson Research Merit Award holder. P.M. acknowledges support from ARC grant FT110100457 and NERC grants NE/J011002/1, and T.R.B. acknowledges support from a Leverhulme Trust Research Fellowship

Hyperdominance in Amazonian Forest Carbon Cycling

While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region

Evolutionary Heritage Influences Amazon Tree Ecology

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure &lt;= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Exchange rate exposure and firm dynamics

This article develops a heterogeneous firm-dynamics model to jointly study firms’ currency debt composition and investment choices. In our model, foreign currency borrowing arises from a dynamic trade-off between exposure to currency risk and growth. The model endogenously generates selection of productive firms into foreign currency borrowing. Among them, firms with high marginal product of capital use foreign loans more intensively. We assess econometrically the model’s predicted pattern of foreign currency borrowing using firm-level census data from the deregulation of these loans in Hungary, calibrate the model, and quantify the aggregate impact of this financing. Our counterfactual exercises show that understanding the characteristics of firms borrowing in foreign currency is critical to assess the aggregate consequences of this financing

Exchange rate exposure and firm dynamics

This paper develops a heterogeneous firm-dynamics model with endogenous currency debt composition to jointly study financing and investment decisions in developing economies. In our model, firms' foreign currency borrowing arises from a trade-off between exposure to currency risk and growth. We assess econometrically the pattern of foreign currency borrowing using firm-level census data on Hungary, calibrate the model and quantify its aggregate impact. Our counterfactual exercises show that foreign currency borrowing can lead to higher growth and that the efficiency of the banking sector to screen productive and capital-scarce firms is essential to reap up the benefits of this financing