bluuebunny/crossref_metadata_2025 huggingface dataset:
L'impact du déficit public sur la vitesse de convergence des économies européennes
Authors: Cadoret Isabelle , Tavera Christophe
Published: September 2011

The Impact of Government Deficits on European Economic Convergence Rates by Isabelle Cadoret and Christophe Tavera

This paper is a theoretical and empirical examination of the consequences of the government deficit criterion contained in the Maastricht Treaty on economic convergence rates in Europe. We use a Solow growth model that explicitly accounts for government deficits. Theoretical analysis shows a multiplicity of equilibria, as well as bifurcation equilibria. A simulation using the model shows that application of the government deficit criterion leads to more rapid and more uniform convergence rates in European countries.
Pacte de stabilité, crédibilité et stabilisation dans l'union monétaire européenne
Authors: Bureau Dominique
Published: September 2011

Pacte de stabilité, crédibilité et stabilisation dans l'Union monétaire européenne

par Dominique Bureau

Le dilemme entre crédibilité monétaire et stabilisation régionale sous jacent au débat sur les critères budgétaires de l'UEM peut être illustré dans le cadre d'un modèle simple, où le choix d'une banque centrale européenne indépendante est supposé résoudre les problèmes de crédibilité monétaire, mais où les États-membres sont supposés conserver une forte capacité de stabilisation budgétaire face à des chocs de demande.

On montre que dans un tel contexte, l'arbitrage entre la crédibilité anti-inflationniste et la stabilisation des chocs asymétriques est délicat, la banque centrale ne pouvant discipliner simplement le biais expansionniste des autorités budgétaires. La politique monétaire constituant d'une certaine manière un bien public, les autorités nationales ont intérêt à se comporter vis- à- vis de celle-ci en passager clandestin. Dans le modèle considéré, qui met donc au premier plan, non pas les externalités intrinsèques, par les importations ou le taux d'intérêt, entre politiques budgétaires des États-membres, mais celle résultant de l'unicité de la politique monétaire, la mise en place de mécanismes tels que ceux envisagés dans le Pacte de stabilité peut alors être vu comme un instrument complémentaire, visant à alléger ce dilemme crédibilité et stabilisation. Permettant de maintenir l'autonomie des autorités budgétaires, il les responsabiliserait cependant si les sanctions sont perçues comme relativement automatiques.
Un modèle d'enchères de bois sur pied
Authors: Elyakime Bernard , Loisel Patrice
Published: September 2011

Modelling Standing Timber Auctions by Bernard Elyakime and Patrice Loisel

In France, standing timber is often sold by auction with a secret reservation price and vaguely defined quantities. We propose two models in which there is an independent private value and different buyers' and sellers' estimates of quantities: one with a known reservation price and then one with a secret reservation price. We study the buyers' and sellers' strategies for working out the seller's expected revenues with and without a secret reserve price. The seller does better in an auction with a secret reservation price under certain market conditions.
La nature des transferts inter vivos en France : investissements humains, aides financières et transmission du patrimoine
Authors: Arrondel Luc , Wolff François-Charles
Published: September 2011

La nature des transferts inter vivos en France : investissements humains, aides financières et transmission du

patrimoine par Luc Arrondel et François-Charles Wolff

Deux hypothèses fondamentales sont avancées pour expliquer les comportements de transferts inter vivos descendants : l' altruisme qui fait dépendre le bien-être des parents de celui de leurs enfants, et Y échange où les deux générations sont impliquées dans des relations de réciprocité. À partir ce ces deux types de comportements, nous étudions les déterminants des différentes aides (logement, argent, prêt, caution) et des donations recensées dans l'enquête "Actifs financiers" de l'Insee réalisée en 1992 sur un échantillon de 9530 ménages. Cette analyse met en évidence plusieurs résultats originaux. Les aides en logement et en argent s'apparentent souvent à des investissements dans le capital humain des enfants. Par contre, les prêts d'argent et la caution correspondent davantage à des transferts qui peuvent être expliqués par le fait que les enfants sont souvent contraints par la liquidité. Contrairement aux prédictions du modèle altruiste, le montant des donations augmente avec les revenus des bénéficiaires et cette pratique apparaît en conséquence comme un transfert anticompensatoire.

Nos résultats confirment également certaines conclusions importantes de travaux français antérieurs à savoir la complémentarité et la transmissibilité des pratiques de transmission. Les aides apparaissent souvent complémentaires, au moins pour certaines d'entre elles. Les ménages aideurs accompagnent par exemple souvent l'aide en logement ou le prêt d'un versement d'argent. Nous observons aussi une forte transmissibilité des pratiques pour la donation et les aides : on donne plus souvent si l'on est donataire, on aide plus fréquemment et de préférence sous la même forme si l'on a été aidé.
Productivité de la recherche et rendements d'échelle dans le secteur pharmaceutique français
Authors: Iung Nicolas , Rupprecht Frédéric
Published: September 2011

Research Productivity and Returns to Scale in the French Pharmaceutical Sector by Nicolas lung and Frederic Rupprecht

This paper studies research productivity in French pharmaceutical laboratories. We measure the elasticities of the number of new products launched and the sales made by these products to the size of the laboratory launching them. Our study suggests that the development of new pharmaceutical products is subject to constant or decreasing returns and economies of scope. These economies could make it profitable for firms working in separate therapeutic fields to merge.

Constant or decreasing returns also prevail in the discovery of blockbusters, but without economies of scope. However, this type of pharmaceutical product might be expected to show increasing returns due to the greater impact of researcher specialisation and the fixed costs associated with purchasing sophisticated equipment.
Commerce international et structures de marché : une vérification empirique
Authors: Fontagné Lionel , Frudenberg Michael , Péridy Nicolas
Published: September 2011

Commerce international et structures de marché : une vérification empirique par Lionel Fontagné, Michel Freudenberg et Nicolas Péridy

Une part importante des échanges internationaux a lieu sur un mode intra-branche (croisement des exportations et importations au sein des branches), en contradiction apparente avec la logique de spécialisation inter-branches selon les avantages comparatifs. Les développements récents de la théorie du commerce international, intégrant de nombreux apports de l'économie industrielle, débouchent toutefois sur une synthèse entre l'approche classique (l'avantage comparatif) et la concurrence imparfaite. On déduit deux ensembles de prédictions testables de cette synthèse, amendée pour prendre en compte la différenciation verticale des produits. L'un concerne les volumes d'échanges bilatéraux, l'autre la nature, inter- ou intra-branche des échanges. On estime des équations de type gravitaire entre pays de FUE12 sur la période 1980-1994. Les approches contemporaines de la spécialisation,_basées sur l'exploitation des rendements croissants, sont validées, mais non l'approche classique en termes d'avantage comparatif. Par contre, cette dernière conserve sa validité à un niveau plus fin, sur les échelles de qualité au sein des branches._Si la différenciation des produits renforce l'échange intra-branche, comme attendu, l'association traditionnelle des économies d'échelle à l'échange intra-branche n'est validée que dans le cas de la différenciation horizontale des produits.
Taxation, capital public et croissance : les méfaits du "court-termisme"
Authors: Rieber Arsène
Published: September 2011

Taxation, capital public et croissance : les méfaits du "court-termisme"

par Arsène Rieber

Dans le cadre d'un modèle de croissance endogène, nous nous intéressons à l'incidence de la politique fiscale sur la dynamique économique. Approfondissant le modèle de Barro (1990), nous imposons une finalité aux prélèvements publics : le financement des infrastructures. Le modèle enseigne que par l'intermédiaire du choix des outils fiscaux, le gouvernement est confronté au résultat suivant : l'objectif de maximiser la dynamique de long terme se traduit par un ralentissement du rythme de convergence. À l'inverse, un gouvernement soumettant sa politique fiscale à des préoccupations d'ajustement de court terme dirigera l'économie vers un équilibre sous-optimal à long terme.
La modélisation Var "structurel" : application à la politique monétaire en France
Authors: Bruneau Catherine , De Bandt Olivier
Published: September 2011

Structural VAR modeling: application to France's monetary policy by Catherine Bruneau and Olivier De Bandt

This paper discusses the purposes and limits of "structural" VAR modeling. It explains the choices that modelers have to make at different stages of the procedure. An illustration is provided by an analysis of monetary policy shocks in France over the 1972:1-1995:2 period. Compared with previous studies of this country, the main finding is the statistically significant effect of monetary policy on economic activity and inflation. This is found by introducing an additional variable that measures budget policy. The article shows that "structural" VARs can be used to analyse the 1993 recession.
Guide pratique des séries non-stationnaires
Authors: Salanié Bernard
Published: September 2011

Guide pratique des séries non-stationnaires par Bernard Salanié

L'objet de ce texte est de présenter les méthodes économétriques disponibles pour procéder à l'estimation et au test de systèmes comprenant des variables non-stationnaires, en insistant sur les contributions récentes qui fournissent des méthodes plus simples et/ou plus robustes que celles qui ont été développées au début des années quatre- vingt. L'approche utilisée est résolument pragmatique : aucun résultat asymptotique n'est démontré, mais on cherche à évaluer les avantages et inconvénients de l'utilisation de chaque procédure.
Redistribution, inégalité et chômage
Authors: Touzé Vincent
Published: September 2011

Redistribution, inégalité et chômage par Vincent Touzé

L'objet de cet article est de proposer un fondement théorique de la relation inégalité-chômage mise en évidence de façon empirique. Pour ce faire, on utilise une économie à générations imbriquées dans laquelle l'État redistribue les richesses entre les individus à l' aide d' une taxation linéaire. Les caractéristiques des individus ne sont pas observables et les paramètres du système de redistribution sont choisis au moyen du modèle de taxation optimale de Mirrlees. Un tel système de redistribution engendre une relation entre inégalité et chômage. Le problème de la redistribution optimale s'envisage comme un arbitrage particulier entre inégalité et chômage. A long terme, l'impact sur le pouvoir d'achat stationnaire peut aussi intervenir. Ces résultats sont illustrés à l'aide d'un exemple numérique.
Changements de composition de la force de travail. Implications pour les salaires et le chômage
Authors: Wasmer Étienne
Published: September 2011

Changes in the Structure of the Labour Force: Wage and Unemployment Implications

by Etienne Wasmer

Some important stylised facts on the leading OECD countries' labour markets and the rise in wage inequalities and unemployment are described and associated with changes in the structure of the labour force. The literature sometimes overlooks the fact that these changes can destabilise the labour markets, by considering the labour supply to be a homogeneous factor. We endeavour to show here that the supply should be represented as heterogeneous in that this rise has been accompanied by a marked change in structure. The labour force has become younger and more female. This paper describes the mechanisms that can create unemployment and inequalities. These supply changes could be viewed as an increase in the number of low- wage-earners. Also worth mentioning is the drop in the actual amount of employment experience among the labour force.
One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences
Authors: Gers Charlotte F , Rosellen Julia , Merkul Eugen , Müller Thomas J J
Published: August 2011

A novel one-pot four-component synthesis of pyrimidyl- and pyrazolylazulenes through the use of glyoxylation–decarbonylative alkynylation–cyclocondensation sequences starting from azulene or guaiazulene as substrates, gives rise to the formation of the target compounds in moderate to good yields.
Abacavir, Didanosine and Tenofovir do not Induce Inflammatory, Apoptotic or Oxidative Stress Genes in Coronary Endothelial Cells
Authors: Kim Chul , Gupta Samir K , Green Linden , Taylor Brian M , Deuter-Reinhard Maja , Desta Zeruesenay , Clauss Matthias
Published: August 2011

Background

The use of abacavir and didanosine in HAART has been associated with an increased risk of myocardial infarction in HIV-infected patients. The aim of this study was to address the development of endothelial dysfunction in cultivated coronary artery endothelial cells (HCAECs) in response to abacavir, didanosine and tenofovir. We examined the impact of these drugs on the expression levels of the proinflammatory, oxidative stress and apoptosis regulating genes in HCAECs.

Methods

We tested gene and protein expression changes in HCAECs in response to abacavir, didanosine and tenofovir using quantitative real-time reverse transciptase PCR, FACS and ELISA. The assessed genes/proteins included the proinflammatory molecules VCAM-1, ICAM-1, MCP-1, RANTES and IL-6. In addition, we assessed the gene expression of the intracellular reactive oxygen producing NADPH oxidase subunit gp91PHOX and the apoptosis regulating molecules Bcl-2 and BAD.

Results

Exposure of HCAECs to abacavir, didanosine and tenofovir resulted in no statistically significant changes in any of the tested genes/proteins at any time point or at any concentration.

Conclusions

We found no evidence that abacavir, didanosine or tenofovir had direct in vitro effects on coronary endothelial cell gene transcription and protein expression of the selected mediators. If abacavir or didanosine increase cardiovascular risk, it is likely not through the direct endothelial activation pathways tested in these experiments. However, further studies are needed to completely exclude the toxicity of abacavir or didanosine on endothelial cells.
Measurement of End-Tidal Carbon Dioxide in Spontaneously Breathing Children After Cardiac Surgery
Authors: Rasera Carmen Caroline , Gewehr Pedro Miguel , Domingues Adriana Maria Trevisan , Junior Fernando Faria
Published: September 2011

Background

Respiratory monitoring is important after surgery to prevent pulmonary complications. End-tidal carbon dioxide (Petco2) measurement by capnometry is an indirect and noninvasive measurement of Pco2 in blood and is accepted and recognized in critical care.

Objectives

To determine the correlation and level of agreement between Petco2 and Paco2 in spontaneously breathing children after cardiac surgery and to determine whether Petco2 measured by using tidal volume (Vt-Petco2) or vital capacity (VC-Petco2) shows more or less significant correlation with Paco2.

Methods

Vt-Petco2 and VC-Petco2 by capnometry and Paco2 by blood gas analysis were measured once a day after tracheal extubation. The determination coefficient and degree of bias between the methods were assessed in children with and without supplemental oxygen.

Results

A total of 172 Vt-Petco2, VC-Petco2, and Paco2 values from 48 children were analyzed. The overall coefficients of determination were 0.84 (P < .001) for Vt-Petco2 and Paco2 and 0.62 (P = .02) for VC-Petco2 and Paco2. The mean gradient for Paco2 to Petco2 in all groups increased with the increase in supplemental oxygen; the gradient was significantly larger in the groups given 2 to 5 L of oxygen per minute.

Conclusions

In spontaneously breathing children, Vt-Petco2 provided a more accurate estimate of Paco2 than did VC-Petco2, especially in children given little or no supplemental oxygen. The difference between the methods was significantly larger in the groups given 2 to 5 L of oxygen per minute.
Ethical Considerations in Global Health for Obstetrician-Gynecologists
Authors: Rockers Mary , Yeh John
Published: September 2011

There is growing interest in the area of global health by obstetricians-gynecologists. As more of these physicians become involved in this important and exciting undertaking, the physicians are potentially exposed to situations in which they may have to deal with ethical questions that they may not have previously considered. Some of the principles which frame the ethical problems that obstetricians-gynecologists may encounter include autonomy, beneficence, nonmaleficence and justice. We believe that exposure to ethical principles and study of cases involving ethical issues will be of benefit to the physicians and their patients, and that this exposure takes place before these doctors are placed in the environments and circumstances they might face as they travel to distant locations.
Rectifiability of Optimal Transportation Plans
Authors: McCann Robert J. , Pass Brendan , Warren Micah
Published: September 2011

The regularity of solutions to optimal transportation problems has become a hot topic in current research. It is well known by now that the optimal measure may not be concentrated on the graph of a continuous mapping unless both the transportation cost and themasses transported satisfy very restrictive hypotheses (including sign conditions on the mixed fourth-order derivatives of the cost function). The purpose of this note is to show that in spite of this, the optimal measure is supported on a Lipschitz manifold, provided only that the cost isC2with non-singular mixed second derivative. We use this result to provide a simple proof that solutions to Monge's optimal transportation problem satisfy a change of variables equation almost everywhere.
The Lang–Weil Estimate for Cubic Hypersurfaces
Authors: Browning T. D.
Published: August 2011

An improved estimate is provided for the number of 𝔽q-rational points on a geometrically irreducible, projective, cubic hypersurface that is not equal to a cone.
Involutions and Anticommutativity in Group Rings
Authors: Goodaire Edgar G. , Milies César Polcino
Published: August 2011

Let g denote an involution on a group G. For any (commutative, associative) ring R (with 1), * extends linearly to an involution of the group ring RG. An element α ∊ RG is symmetric if α* = α and skew-symmetric if α* = -α. The skew-symmetric elements are closed under the Lie bracket, [αβ] = αβ - βα. In this paper, we investigate when this set is also closed under the ring product in RG. The symmetric elements are closed under the Jordan product, α˚α = αβ +βα. Here, we determine when this product is trivial. These two problems are analogues of problems about the skew-symmetric and symmetric elements in group rings that have received a lot of attention.
SOA formation from the atmospheric oxidation of 2-methyl-3-buten-2-ol and its implications for PM2.5
Authors: Jaoui M. , Kleindienst T. E. , Offenberg J. H. , Lewandowski M. , Lonneman W. A.
Published: August 2011

Abstract. The formation of secondary organic aerosol (SOA) generated by irradiating 2-methyl-3-buten-2-ol (MBO) in the presence and/or absence of NOx, H2O2, and/or SO2 was examined. Experiments were conducted in smog chambers operated either in dynamic or steady-state mode. A filter/denuder sampling system was used for simultaneously collecting gas and particle phase products. The structural characterization of gas and particulate products was investigated using BSTFA, BSTFA + PFBHA, and DNPH derivatization techniques followed by GC-MS and liquid chromatography analysis. This analysis showed the occurrence of more than 68 oxygenated organic compounds in the gas and particle phase, 28 of which were identified. The major components observed include 2,3-dihydroxyisopentanol (DHIP), 2-hydroxy-2-oxoisopentanol, 2,3-dihydroxy-3-methylbutanal, 2,3-dihydroxy-2-methylsuccinic acid, 2-hydroxy-2-methylpropanedioic acid, acetone, glyoxal, methylglyoxal, glycolaldehyde, and formaldehyde. Most of these oxygenated compounds were detected for the first time in this study. While measurements of the gas phase photooxidation products have been made, the focus of this work has been an examination of the particle phase. SOA from some experiments was analyzed for the organic mass to organic carbon ratio (OM/OC), the effective enthalpy of vaporization (ΔHvapeff), and the aerosol yield. Additionally, aerosol size, volume, and number concentrations were measured by a Scanning Mobility Particle Sizer coupled to a Condensation Particle Counter system. The OM/OC was found to be 2.1 in MBO/H2O2 system. The ΔHvapeff was 41 kJ mol−1, a value similar to that of isoprene SOA. The laboratory SOA yield measured in this study was found to be 0.7 % in MBO/H2O2 for an aerosol mass of 33 μg m−3. Time profiles and proposed reaction schemes are provided for selected compounds. The contribution of SOA products from MBO oxidation to ambient PM2.5 was investigated by analyzing a series of ambient PM2.5 samples collected in several places around the United States. In addition to the occurrence of several organic compounds in both field and laboratory samples, DHIP was found to originate only from the oxidation of MBO, and therefore this compound could serve as a tracer for MBO SOA. Initial attempts have been made to quantify the concentrations of DHIP and other compounds based on surrogate compound calibrations. The average concentrations of DHIP in ambient PM2.5 samples from Duke Forest, NC ranged from zero during cold seasons in areas with low MBO emission rates to approximately 1 ng m−3 during warm seasons in areas with high MBO emission rates. This appears to be the first time that DHIP has been detected in ambient PM2.5 samples. The occurrence of several other compounds in both laboratory and field samples suggests that SOA originating from MBO can contribute under selected ambient conditions to the ambient aerosol mainly in areas where MBO emissions are high.
Observations of electron vorticity in the inner plasma sheet
Authors: Gurgiolo C. , Goldstein M. L. , Viñas A. F. , Matthaeus W. H. , Fazakerley A. N.
Published: September 2011

Abstract. From a limited number of observations it appears that vorticity is a common feature in the inner plasma sheet. With the four Cluster spacecraft and the four PEACE instruments positioned in a tetrahedral configuration, for the first time it is possible to directly estimate the electron fluid vorticity in a space plasma. We show examples of electron fluid vorticity from multiple plasma sheet crossings. These include three time periods when Cluster passed through a reconnection ion diffusion region. Enhancements in vorticity are seen in association with each crossing of the ion diffusion region.
Nitrogen enrichment enhances the dominance of grasses over forbs in a temperate steppe ecosystem
Authors: Song L. , Bao X. , Liu X. , Zhang Y. , Christie P. , Fangmeier A. , Zhang F.
Published: August 2011

Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperate steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p < 0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant δ15N and soil mineral N increased with N addition, showing positive relationships between plant δ15N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha−1 yr−1 treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show N deposition-induced changes in soil N transformations and plant N assimilation that are closely related to changes in species composition and biomass accumulation in this temperate steppe ecosystem.
Seasonality of ecosystem respiration in a double-cropping paddy field in Bangladesh
Authors: Hossen M. S. , Mano M. , Miyata A. , Baten M. A. , Hiyama T.
Published: August 2011

Abstract. Ecosystem respiration (RE) from cultivated ecosystems is important for understanding the role of these ecosystems in the global carbon balance. To evaluate carbon dynamics in a double-rice cropping paddy field, we conducted long-term measurements at Mymensingh, Bangladesh in 2007 using a tower-based eddy covariance technique. The study objectives were to investigate the diurnal and seasonal variations in RE and to develop and evaluate empirical models for predicting variations in RE using environmental parameters. We found that the diurnal pattern of RE was driven by soil temperature (Ts) whereas the seasonal variation in RE was controlled primarily by Ts and soil water content (SWC). Under high biomass conditions, Ts plays a dominant role in the magnitude of CO2 release. Both the amount and magnitude of RE variation were larger in the "Boro" dry-season rice growing period from late winter to mid-summer than in the "Aman" wet-season rice growing period from late summer to early winter. Annually, the ratio of RE to gross primary production (GPP) was 0.67, indicating a net sink of carbon; the two growing seasons had RE/GPP ratios of 0.58 and 0.52. A model using Ts, SWC, and aboveground biomass predicted daily RE with R2 values of 0.87 and 0.62 for the Boro and Aman seasons, respectively.
The Joint UK Land Environment Simulator (JULES), model description – Part 2: Carbon fluxes and vegetation dynamics
Authors: Clark D. B. , Mercado L. M. , Sitch S. , Jones C. D. , Gedney N. , Best M. J. , Pryor M. , Rooney G. G. , Essery R. L. H. , Blyth E. , Boucher O. , Harding R. J. , Huntingford C. , Cox P. M.
Published: September 2011

Abstract. The Joint UK Land Environment Simulator (JULES) is a process-based model that simulates the fluxes of carbon, water, energy and momentum between the land surface and the atmosphere. Many studies have demonstrated the important role of the land surface in the functioning of the Earth System. Different versions of JULES have been employed to quantify the effects on the land carbon sink of climate change, increasing atmospheric carbon dioxide concentrations, changing atmospheric aerosols and tropospheric ozone, and the response of methane emissions from wetlands to climate change. This paper describes the consolidation of these advances in the modelling of carbon fluxes and stores, in both the vegetation and soil, in version 2.2 of JULES. Features include a multi-layer canopy scheme for light interception, including a sunfleck penetration scheme, a coupled scheme of leaf photosynthesis and stomatal conductance, representation of the effects of ozone on leaf physiology, and a description of methane emissions from wetlands. JULES represents the carbon allocation, growth and population dynamics of five plant functional types. The turnover of carbon from living plant tissues is fed into a 4-pool soil carbon model. The process-based descriptions of key ecological processes and trace gas fluxes in JULES mean that this community model is well-suited for use in carbon cycle, climate change and impacts studies, either in standalone mode or as the land component of a coupled Earth system model.
Plant functional type mapping for earth system models
Authors: Poulter B. , Ciais P. , Hodson E. , Lischke H. , Maignan F. , Plummer S. , Zimmermann N. E.
Published: August 2011

Abstract. The sensitivity of global carbon and water cycling to climate variability is coupled directly to land cover and the distribution of vegetation. To investigate biogeochemistry-climate interactions, earth system models require a representation of vegetation distributions that are either prescribed from remote sensing data or simulated via biogeography models. However, the abstraction of earth system state variables in models means that data products derived from remote sensing need to be post-processed for model-data assimilation. Dynamic global vegetation models (DGVM) rely on the concept of plant functional types (PFT) to group shared traits of thousands of plant species into just several classes. Available databases of observed PFT distributions must be relevant to existing satellite sensors and their derived products, and to the present day distribution of managed lands. Here, we develop four PFT datasets based on land-cover information from three satellite sensors (EOS-MODIS 1 km and 0.5 km, SPOT4-VEGETATION 1 km, and ENVISAT-MERIS 0.3 km spatial resolution) that are merged with spatially-consistent Köppen-Geiger climate zones. Using a beta (β) diversity metric to assess reclassification similarity, we find that the greatest uncertainty in PFT classifications occur most frequently between cropland and grassland categories, and in dryland systems between shrubland, grassland and forest categories because of differences in the minimum threshold required for forest cover. The biogeography-biogeochemistry DGVM, LPJmL, is used in diagnostic mode with the four PFT datasets prescribed to quantify the effect of land-cover uncertainty on climatic sensitivity of gross primary productivity (GPP) and transpiration fluxes. Our results show that land-cover uncertainty has large effects in arid regions, contributing up to 30 % (20 %) uncertainty in the sensitivity of GPP (transpiration) to precipitation. The availability of plant functional type datasets that are consistent with current satellite products and adapted for earth system models is an important component for reducing the uncertainty of terrestrial biogeochemistry to climate variability.
Spectral representation of the annual cycle in the climate change signal
Authors: Bosshard T. , Kotlarski S. , Ewen T. , Schär C.
Published: September 2011

Abstract. The annual cycle of temperature and precipitation changes as projected by climate models is of fundamental interest in climate impact studies. Its estimation, however, is impaired by natural variability. Using a simple form of the delta change method, we show that on regional scales relevant for hydrological impact models, the projected changes in the annual cycle are prone to sampling artefacts. For precipitation at station locations, these artefacts may have amplitudes that are comparable to the climate change signal itself. Therefore, the annual cycle of the climate change signal should be filtered when generating climate change scenarios. We test a spectral smoothing method to remove the artificial fluctuations. Comparison against moving monthly averages shows that sampling artefacts in the climate change signal can successfully be removed by spectral smoothing. The method is tested at Swiss climate stations and applied to regional climate model output of the ENSEMBLES project. The spectral method performs well, except in cases with a strong annual cycle and large relative precipitation changes.
Statistical inference from atmospheric time series: detecting trends and coherent structures
Authors: Gluhovsky A.
Published: August 2011

Abstract. Standard statistical methods involve strong assumptions that are rarely met in real data, whereas resampling methods permit obtaining valid inference without making questionable assumptions about the data generating mechanism. Among these methods, subsampling works under the weakest assumptions, which makes it particularly applicable for atmospheric and climate data analyses. In the paper, two problems are addressed using subsampling: (1) the construction of simultaneous confidence bands for the unknown trend in a time series that can be modeled as a sum of two components: deterministic (trend) and stochastic (stationary process, not necessarily an i.i.d. noise or a linear process), and (2) the construction of confidence intervals for the skewness of a nonlinear time series. Non-zero skewness is attributed to the occurrence of coherent structures in turbulent flows, whereas commonly employed linear time series models imply zero skewness.
Twenty-Four–Hour Bence-Jones Protein Determinations: Can We Ensure Accuracy?
Authors: Kaplan Jennifer S , Horowitz Gary L
Published: September 2011

Context.—Light chain disease represents 15% to 20% of cases of multiple myeloma. Current guidelines recommend monitoring these patients with 24-hour urine collections.

Objective.—To determine the reliability of 24-hour urine collections in assessing the amount of Bence-Jones protein (BJP).

Design.—We included all patients from our institution from 2003 through 2008 with BJP who had more than four 24-hour urine collections. We compared BJP excretion calculated from the submitted 24-hour collection with BJP excretion calculated by normalizing the collection to that patient's mean 24-hour creatinine excretion. We also looked at differences in serial values with these 2 methods. In addition, we evaluated the feasibility of using random urine samples to determine BJP excretion.

Results.—A total of 14 patients with 135 24-hour urine collections met our inclusion criteria. The 24-hour urine creatinine excretion for each patient, which should be reasonably constant, varied considerably (coefficient of variation range 12%–30%). Differences in the 2 methods of calculating BJP excretion ranged from −1588 to 2315 mg/d. Among a total of 121 serial 24-hour measurements, the differences were clinically significant in 37 (30%). Among a total of 23 random urine samples from 11 of these patients submitted within 10 days of a 24-hour collection, the estimated BJP excretion appeared to be accurate in at least 18 (78%).

Conclusions.—Twenty-four–hour urine collections for BJP are, in practice, often misleading. At a minimum, one should verify that the 24-hour creatinine excretion is accurate. In addition, it may be possible to use the protein/creatinine ratio from random urine samples to determine 24-hour BJP excretion.
Self‐reported knee malalignment in early adult life as an independent risk for knee chondrocalcinosis
Authors: Abhishek Abhishek , Doherty Sally , Maciewicz Rose A. , Muir Kenneth R. , Zhang Weiya , Doherty Michael
Published: September 2011

Objective

To determine if self‐reported current and early adult life knee malalignment is associated with knee chondrocalcinosis (CC).

Methods

A case–control study embedded in the Genetics of Osteoarthritis and Lifestyle (GOAL) study was performed. A validated self‐reported line‐drawing instrument was mailed to 3,022 participants of GOAL, inquiring about knee malalignment (straight, valgus, varus) in their third decade (20s) and currently. Self‐reported weight in 20s and present weight and height measured at the initial visit were used to calculate body mass index (BMI) in 20s and currently. Occupational risk was present if participants self‐reported mechanically demanding activities in their longest held job. Cases were participants with radiographic CC at any tibiofemoral (TF) joints. Osteoarthritis was defined as a Kellgren/Lawrence score of ≥3 at TF joints or patellofemoral joints. Odds ratio (OR), adjusted OR, and 95% confidence interval (95% CI) were calculated for associations with knee CC.

Results

A total of 2,167 participants responded to the questionnaire, of which 7.5% respondents had knee CC. Knee CC was associated with self‐reported varus (adjusted OR 1.77 [95% CI 1.05, 2.98]) and any knee malalignment in 20s (adjusted OR 1.64 [95% CI 1.02, 2.64]). This association was not restricted to the mechanically loaded TF compartment. There was no association between current knee malalignment and knee CC. Age (adjusted OR 1.73 [95% CI 1.36, 2.19]) and knee OA (adjusted OR 2.88 [95% CI 1.89, 4.38]) were associated with knee CC. There was no association between BMI in 20s (adjusted OR 1.14 [95% CI 0.92, 1.42]), occupational risk (adjusted OR 1.32 [95% CI 0.94, 1.85]), and knee CC.

Conclusion

Early life knee malalignment, predominantly varus, is an independent risk factor for knee CC. This association is not restricted to the mechanically loaded compartment, implying a generalized predisposition throughout the knee.
Fault tolerance evaluation based on the lattice of system configurations
Authors: Staroswiecki Marcel , Commault Christian , Dion Jean‐Michel
Published: September 2011

The lattice of component subsets is a very useful structure for addressing fault tolerance and architecture design problems for systems described as a set of components. This paper presents a number of concepts and techniques that are associated with this lattice to evaluate the degree of fault tolerance of a given property and to classify components with respect to their usefulness for this property. Being very general, the approach needs no assumption on the system, nor on the properties to be satisfied, and allows both deterministic and probabilistic measures to be used. A sensor selection example illustrates the practical use of the proposed tools. Copyright © 2011 John Wiley & Sons, Ltd.
Charged Hexosaminides as New Substrates for β‐N‐Acetylhexosaminidase‐Catalyzed Synthesis of Immunomodulatory Disaccharides
Authors: Bojarová Pavla , Slámová Kristýna , Křenek Karel , Gažák Radek , Kulik Natallia , Ettrich Rüdiger , Pelantová Helena , Kuzma Marek , Riva Sergio , Adámek David , Bezouška Karel , Křen Vladimír
Published: September 2011

This work is a structure‐activity relationship study that investigates the influence of the nature and amount of negative charge in carbohydrate substrates on the affinity of β‐N‐acetylhexosaminidases, and on the stimulation of natural killer cells. It describes synthetic procedures yielding novel glycosides that are useful in immunoactivation. Specifically, we present a thorough study on the ability of six C‐6 modified β‐N‐acetylhexosaminides (aldehyde, uronate, 6‐O‐sulfate, 6‐O‐phosphate) to serve as substrates for cleavage and glycosylation by a library of β‐N‐acetylhexosaminidases from various sources. Four novel disaccharides with one or two (negatively) charged groups were prepared in synthetic reactions in good yields. Surprisingly, the 6‐O‐phosphorylated substrate, although cleaved by a number of enzymes from the series, worked neither as a donor nor as an acceptor in transglycosylation reactions. The results of wet experiments were supported by molecular modeling of substrates in the active site of two representative enzymes from the screening. All ten prepared compounds were examined in terms of their immunoactivity, namely as ligands of two activation receptors of natural killer (NK) cells, NKR‐P1 and CD69, both with isolated proteins and whole cells. Sulfated disaccharides in particular acted as very efficient protectants of NK cells against activation‐induced apoptosis, and as stimulants of the natural killing of resistant tumor cells, which makes them good candidates for potential clinical use in cancer treatment.
Genetic ancestry and indigenous heritage in a Native American Descendant Community in Bermuda
Authors: Gaieski Jill B. , Owings Amanda C. , Vilar Miguel G. , Dulik Matthew C. , Gaieski David F. , Gittelman Rachel M. , Lindo John , Gau Lydia , Schurr Theodore G. ,   The Genographic Consortium
Published: September 2011

Discovered in the early 16th century by European colonists, Bermuda is an isolated set of islands located in the mid‐Atlantic. Shortly after its discovery, Bermuda became the first English colony to forcibly import its labor by trafficking in enslaved Africans, white ethnic minorities, and indigenous Americans. Oral traditions circulating today among contemporary tribes from the northeastern United States recount these same events, while, in Bermuda, St. David's Islanders consider their histories to be linked to a complex Native American, European, and African past. To investigate the influence of historical events on biological ancestry and native cultural identity, we analyzed genetic variation in 111 members of Bermuda's self‐proclaimed St. David's Island Native Community. Our results reveal that the majority of mitochondrial DNA (mtDNA) and Y‐chromosome haplotypes are of African and West Eurasian origin. However, unlike other English‐speaking New World colonies, most African mtDNA haplotypes appear to derive from central and southeast Africa, reflecting the extent of maritime activities in the region. In light of genealogical and oral historical data from the St. David's community, the low frequency of Native American mtDNA and NRY lineages may reflect the influence of genetic drift, the demographic impact of European colonization, and historical admixture with persons of non‐native backgrounds, which began with the settlement of the islands. By comparing the genetic data with genealogical and historical information, we are able to reconstruct the complex history of this Bermudian community, which is unique among New World populations. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Common features of sexual dimorphism in the cranial airways of different human populations
Authors: Bastir Markus , Godoy Paula , Rosas Antonio
Published: September 2011

Sexual dimorphism in the human craniofacial system is an important feature of intraspecific variation in recent and fossil humans. Although several studies have reported different morphological patterns of sexual dimorphism in different populations, this study searches for common morphological aspects related to functional anatomy of the respiratory apparatus. 3D geometric morphometrics were used to test the hypothesis that due to higher daily energy expenditure and associated greater respiratory air consumption as well as differences in body composition, males should have absolutely and relatively greater air passages in the bony cranial airways than females. We measured 25 3D landmarks in five populations (N = 212) of adult humans from different geographic regions. Male average cranial airways were larger in centroid sizes than female ones. Males tended to show relatively taller piriform apertures and, more consistently, relatively taller internal nasal cavities and choanae than females. Multivariate regressions and residual analysis further indicated that after standardizing to the same size, males still show relatively larger airway passages than females. Because the dimensions of the choanae are limiting factors for air transmission towards the noncranial part of the respiratory system, the identified sex‐specific differences in cranial airways, possibly shared among human populations, may be linked with sex‐specific differences in body size, composition, and energetics. These findings may be important to understanding trends in hominin facial evolution. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Synthesis of an acrylate elastomer with UV stabilization and its application in polyoxymethylene
Authors: Wu Guibo , Yang Fan , Zhang Shiling , Ren Xiancheng
Published: September 2011

In this study, an acrylate elastomer with light‐stable functional groups was synthesized by methyl methacrylate (MMA), butyl acrylate (BA), and a polymerizable UV stabilizer 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylproroxy) benzophenone (BPMA) via emulsion polymerization, and the product was poly[methyl methacrylate‐co‐butyl acrylate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylproroxy) benzophenone] [poly(MMA‐co‐BA‐co‐BPMA)]. The composition and characteristics of poly (MMA‐co‐BA‐co‐BPMA) were determined by using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H‐NMR), and ultraviolet–visible absorption spectroscopy (UV–vis). Further, the obtained poly(MMA‐co‐BA‐co‐BPMA) was blended with polyoxymethylene (POM) to modify its photostabilization, as well as the mechanical properties of POM composite were tested before and after UV irradiation. The result showed that poly(MMA‐co‐BA‐co‐BPMA) can be dispersed well in the POM matrix, which could play a role of improving compatibility with and toughening for POM, and its light‐stable functional groups could increase the UV resistance of POM composite. Mechanical properties of modified POM were kept well with higher impact strength and elongation at break than pure POM after UV irradiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Grafting of styrene onto polyethylene in near critical media
Authors: Martini Raquel E. , Brignole Esteban A. , Barbosa Silvia E.
Published: September 2011

In this work, near critical n‐heptane is used as reaction medium for the copolymerization of polyethylene with styrene monomer, using alkylation reaction with different amounts of aluminum chloride (AlCl3) as catalyst. In this way, polyethylene chains will be more available to react with the catalyst. The reaction effect on pure reactants, as well as, the catalyst activity was previously investigated. The reaction occurrence was corroborated by analyzing the reaction products before and after careful polystyrene extraction with tetrahydrofuran. The reaction products were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, and size exclusion chromatography. The possible architecture for the copolymer molecule was proposed from the molecular characterization results. On the other hand, the polystyrene grafting modifies final properties of polyethylene, increasing the oxygen barrier properties without deteriorating significantly the mechanical properties of the films. In this sense this reaction seems to be a promising route to modify PE films to increase the barrier properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Application of anionic acrylamide‐based hydrogels in the removal of heavy metals from waste water
Authors: Atta Ayman M. , Ismail Husein S. , Elsaaed Ashraf M.
Published: September 2011

Crosslinked acrylamide (AM) and 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) homopolymers and copolymers were prepared by free radical solution polymerization using N,N′‐methylenebisacrylamide as the crosslinker. The chemical structures of hydrogels were characterized by FTIR analysis and the results were consistent with the expected structures. These hydrogels were used for the separation of Cd(II), Cu(II), and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel towards the different metal ions tested was Cd(II) > Cu(II) > Fe(III). It was observed that the specific interaction between metal ions and ionic comonomers in the hydrogel affected the metal binding capacity of the hydrogel. The recovery of metal ions was also investigated in acid media. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012