bluuebunny/crossref_metadata_2025 huggingface dataset:
Les raisons de l'existence et du succès des partis ethniques en Amérique Latine. Les cas de la Bolivie, de l'Équateur, du Guatemala, du Mexique, du Nicaragua et du Pérou (1990-2005)
Authors: Martí I Puig Salvador
Published: October 2010

Résumé Cet article vise à savoir s’il existe un lien causal entre la présence et la pertinence des partis ethniques (PE) dans six pays d’Amérique Latine (Bolivie, Équateur, Guatemala, Mexique, Nicaragua et Pérou) et les “conditions favorables” telles que définies par les différentes branches de la littérature sur l’action collective, notamment les structures d’opportunités politiques, les répertoires de l’action collective, les cadres cognitifs et les structures connectives des organisations. Dans ce but, nous avons effectué une analyse qualitative multicausale basée sur des cas et des variables (avec N = 6) utilisant la logique boléenne de simplification des structures de données complexes. L’objectif est d’identifier les causes différentes produisant un phénomène, c’est-à-dire, ici, les raisons de la présence et du succès des partis ethniques en Bolivie, en Équateur et au Nicaragua, contrairement au Guatemala, au Mexique ou au Pérou.
La fabrication des positions nationales dans l'Union européenne, la France, le Royaume Uni et la sécurité intérieure
Authors: de Maillard Jacques , Smith Andy
Published: October 2010

Résumé Cet article vise à contribuer à la question de la formation des positions nationales défendues dans les négociations européennes. Cette activité combine trois dimensions : les négociations interministérielles, l’ajustement entre les négociateurs localisés dans les espaces politiques nationaux et européen et la plus ou moins grande ouverture sur les acteurs extérieurs à la communauté de politiques publiques. Fondé sur les cas britanniques et français dans le domaine de la coopération policière et judiciaire pénale, il montre que si ces deux États-membres partagent un souci de coordination fortement centralisée et très centrée sur les ministères spécialisés, ils présentent un degré de concurrence interadministrative et de rapport au politique partiellement contrastés.
A Micro-Economic Approach to Geographic Market Definition on Local Retail Markets: Demand Side Considerations
Authors: Beckert Walter
Published: October 2010

This paper formalizes an empirically implementable framework for the definition of local antitrust markets in retail markets. This framework rests on a demand model that captures the trade-off between distance and pecuniary cost across alternative shopping destinations within local markets. The paper develops, and presents estimation results for, an empirical demand model at the store level for groceries in the UK.
Black carbon measurements in the boundary layer over western and northern Europe
Authors: McMeeking G. R. , Hamburger T. , Liu D. , Flynn M. , Morgan W. T. , Northway M. , Highwood E. J. , Krejci R. , Allan J. D. , Minikin A. , Coe H.
Published: October 2010

Abstract. Europe is a densely populated region that is a significant global source of black carbon (BC) aerosol, but there is a lack of information regarding the physical properties and spatial/vertical distribution of rBC in the region. We present the first aircraft observations of sub-micron refractory BC (rBC) aerosol concentrations and physical properties measured by a single particle soot photometer (SP2) in the lower troposphere over Europe. The observations spanned a region roughly bounded by 50° to 60° N and from 15° W to 30° E. The measurements, made between April and September 2008, showed that average rBC mass concentrations ranged from about 300 ng m−3 near urban areas to approximately 50 ng m−3 in remote continental regions, lower than previous surface-based measurements. rBC represented between 0.5 and 3% of the sub-micron aerosol mass. Black carbon mass size distributions were log-normally distributed and peaked at approximately 180 nm, but shifted to smaller diameters (~160 nm) near source regions. rBC was correlated with carbon monoxide (CO) but had different ratios to CO depending on location and air mass. Light absorption coefficients were measured by particle soot absorption photometers on two separate aircraft and showed similar geographic patterns to rBC mass measured by the SP2. We summarize the rBC and light absorption measurements as a function of longitude and air mass age and also provide profiles of rBC mass concentrations and size distribution statistics. Our results will help evaluate model-predicted regional rBC concentrations and properties and determine regional and global climate impacts from rBC due to atmospheric heating and surface dimming.
HOx observations over West Africa during AMMA: impact of isoprene and NOx
Authors: Stone D. , Evans M. J. , Commane R. , Ingham T. , Floquet C. F. A. , McQuaid J. B. , Brookes D. M. , Monks P. S. , Purvis R. , Hamilton J. F. , Hopkins J. , Lee J. , Lewis A. C. , Stewart D. , Murphy J. G. , Mills G. , Oram D. , Reeves C. E. , Heard D. E.
Published: October 2010

Abstract. Aircraft OH and HO2 measurements made over West Africa during the AMMA field campaign in summer 2006 have been investigated using a box model constrained to observations of long-lived species and physical parameters. "Good" agreement was found for HO2 (modelled to observed gradient of 1.23 ± 0.11). However, the model significantly overpredicts OH concentrations. The reasons for this are not clear, but may reflect instrumental instabilities affecting the OH measurements. Within the model, HOx concentrations in West Africa are controlled by relatively simple photochemistry, with production dominated by ozone photolysis and reaction of O(1D) with water vapour, and loss processes dominated by HO2 + HO2 and HO2 + RO2. Isoprene chemistry was found to influence forested regions. In contrast to several recent field studies in very low NOx and high isoprene environments, we do not observe any dependence of model success for HO2 on isoprene and attribute this to efficient recycling of HOx through RO2 + NO reactions under the moderate NOx concentrations (5–300 ppt NO in the boundary layer, median 76 ppt) encountered during AMMA. This suggests that some of the problems with understanding the impact of isoprene on atmospheric composition may be limited to the extreme low range of NOx concentrations.
Evaluation of cloud convection and tracer transport in a three-dimensional chemical transport model
Authors: Feng W. , Chipperfield M. P. , Dhomse S. , Monge-Sanz B. M. , Yang X. , Zhang K. , Ramonet M.
Published: October 2010

Abstract. We investigate the performance of cloud convection and tracer transport in a global off-line 3-D chemical transport model. Various model simulations are performed using different meteorological (re)analyses (ERA-40, ECMWF operational and ECMWF Interim) to diagnose the updraft mass flux, convective precipitation and cloud top height. The diagnosed upward mass flux distribution from TOMCAT agrees quite well with the ECMWF reanalysis data (ERA-40 and ERA-Interim) below 200 hPa. Inclusion of midlevel convection improves the agreement at mid-high latitudes. However, the reanalyses show strong convective transport up to 100 hPa, well into the tropical tropopause layer (TTL), which is not captured by TOMCAT. Similarly, the model captures the spatial and seasonal variation of convective cloud top height although the mean modelled value is about 2 km lower than observed. The ERA-Interim reanalyses have smaller archived upward convective mass fluxes than ERA-40, and smaller convective precipitation, which is in better agreement with satellite-based data. TOMCAT captures these relative differences when diagnosing convection from the large-scale fields. The model also shows differences in diagnosed convection with the version of the operational analyses used, which cautions against using results of the model from one specific time period as a general evaluation. We have tested the effect of resolution on the diagnosed modelled convection with simulations ranging from 5.6° × 5.6° to 1° × 1°. Overall, in the off-line model, the higher model resolution does not make a large change to the diagnosed convective tracer transport. Similarly, the resolution of the forcing winds in the higher resolution CTM does not make a large improvement compared to the archived mass fluxes. Including a radon tracer in the model confirms the importance of convection for reproducing observed midlatitude profiles. The model run using archived mass fluxes transports significantly more radon to the upper troposphere but the available data does not strongly discriminate between the different model versions.
On the behaviour of the tropopause folding events over the Tibetan Plateau
Authors: Chen X. L. , Ma Y. M. , Kelder H. , Su Z. , Yang K.
Published: October 2010

Abstract. Due to its harsh natural conditions, there had not been any intensive radiosonde observations over the Tibetan Plateau (TP) until the year 2008, when a regional radiosonde observation network was implemented through a Sino–Japan joint cooperation project. This paper reports new findings on the structure of upper troposphere and lower stratosphere (UTLS) layer, and provides evidence for stratosphere and troposphere exchange (STE) over the TP. Due to sparseness of high resolution sonde data, many previous studies assumed that there was only one thermal tropopause over the TP. Actually the radiosonde temperature profiles at pre-onset time of the Asian monsoon over the TP often exhibit a multiple tropopause (MT). The MT occurs in winter time with much higher frequency than any previous estimations over the Plateau. The MT during this time period is associated with tropopause folding near the subtropical westerly jet. The MT consistently varied with the movement of the jet. The MT becomes a single tropopause with the development of the monsoon. According to their height distribution, the MT can be divided into tropical and polar characterized tropopauses. Detailed analyses of MT characteristics are reported in this paper. Although some scientists have analyzed global MT events (with data including GPS radio occultation, ERA40 data and Integrated Global Radiosonde Archive database), the frequency of their MT occurrences in winter season over the plateau is largely under-estimated. This significant difference must be caused by the coarse vertical resolution of these data. The stratospheric intruding episodes are generally associated with the presence of subtropical westerly jet stream over the Plateau. The subtropical jet causes dynamic tropopause foldings over the plateau, which have been observed by us as thermal MT events. Intrusions of high latitude stratospheric ozone rich air into the troposphere over the plateau give us a new explanation to why total column ozone in winter is higher than that in summer.
Retrieval of aerosol optical depth in vicinity of broken clouds from reflectance ratios: case study
Authors: Kassianov E. , Ovchinnikov M. , Berg L. K. , McFarlane S. A. , Flynn C. , Ferrare R. , Hostetler C. , Alexandrov M.
Published: October 2010

Abstract. A recently developed reflectance ratio (RR) method for the retrieval of aerosol optical depth (AOD) is evaluated using extensive airborne and ground-based data sets collected during the Cloud and Land Surface Interaction Campaign (CLASIC) and the Cumulus Humilis Aerosol Processing Study (CHAPS), which took place in June 2007 over the US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains site. A detailed case study is performed for a field of single-layer shallow cumuli observed on 12 June 2007. The RR method is applied to retrieve the spectral values of AOD from the reflectance ratios measured by the MODIS Airborne Simulator (MAS) for two pairs of wavelengths (660 and 470 nm, 870 and 470 nm) collected at a spatial resolution of 0.05 km. The retrieval is compared with an independent AOD estimate from three ground-based Multi-filter Rotating Shadowband Radiometers (MFRSRs). The interpolation algorithm that is used to project MFRSR point measurements onto the aircraft flight tracks is tested using AOD derived from NASA Langley High Spectral Resolution Lidar (HSRL). The RR AOD estimates are in a good agreement (within 5%) with the MFRSR-derived AOD values for the 660-nm wavelength. The AODs obtained from MAS reflectance ratios overestimate those derived from MFRSR measurements by 15–30% for the 470-nm wavelength and underestimate the 870-nm AOD by the same amount.
Calibration of the Total Carbon Column Observing Network using aircraft profile data
Authors: Wunch D. , Toon G. C. , Wennberg P. O. , Wofsy S. C. , Stephens B. B. , Fischer M. L. , Uchino O. , Abshire J. B. , Bernath P. , Biraud S. C. , Blavier J.-F. L. , Boone C. , Bowman K. P. , Browell E. V. , Campos T. , Connor B. J. , Daube B. C. , Deutscher N. M. , Diao M. , Elkins J. W. , Gerbig C. , Gottlieb E. , Griffith D. W. T. , Hurst D. F. , Jiménez R. , Keppel-Aleks G. , Kort E. A. , Macatangay R. , Machida T. , Matsueda H. , Moore F. , Morino I. , Park S. , Robinson J. , Roehl C. M. , Sawa Y. , Sherlock V. , Sweeney C. , Tanaka T. , Zondlo M. A.
Published: October 2010

Abstract. The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. These calibrations are compared with similar observations made in 2004 and 2006. The results indicate that a single, global calibration factor for each gas accurately captures the TCCON total column data within error.
Sensitivity of the simulated precipitation to changes in convective relaxation time scale
Authors: Mishra S. K. , Srinivasan J.
Published: October 2010

Abstract. The paper describes the sensitivity of the simulated precipitation to changes in convective relaxation time scale (TAU) of Zhang and McFarlane (ZM) cumulus parameterization, in NCAR-Community Atmosphere Model version 3 (CAM3). In the default configuration of the model, the prescribed value of TAU, a characteristic time scale with which convective available potential energy (CAPE) is removed at an exponential rate by convection, is assumed to be 1 h. However, some recent observational findings suggest that, it is larger by around one order of magnitude. In order to explore the sensitivity of the model simulation to TAU, two model frameworks have been used, namely, aqua-planet and actual-planet configurations. Numerical integrations have been carried out by using different values of TAU, and its effect on simulated precipitation has been analyzed. The aqua-planet simulations reveal that when TAU increases, rate of deep convective precipitation (DCP) decreases and this leads to an accumulation of convective instability in the atmosphere. Consequently, the moisture content in the lower- and mid- troposphere increases. On the other hand, the shallow convective precipitation (SCP) and large-scale precipitation (LSP) intensify, predominantly the SCP, and thus capping the accumulation of convective instability in the atmosphere. The total precipitation (TP) remains approximately constant, but the proportion of the three components changes significantly, which in turn alters the vertical distribution of total precipitation production. The vertical structure of moist heating changes from a vertically extended profile to a bottom heavy profile, with the increase of TAU. Altitude of the maximum vertical velocity shifts from upper troposphere to lower troposphere. Similar response was seen in the actual-planet simulations. With an increase in TAU from 1 h to 8 h, there was a significant improvement in the simulation of the seasonal mean precipitation. The fraction of deep convective precipitation was in much better agreement with satellite observations.
Density/area power-law models for separating multi-scale anomalies of ore and toxic elements in stream sediments in Gejiu mineral district, Yunnan Province, China
Authors: Cheng Q. , Xia Q. , Li W. , Zhang S. , Chen Z. , Zuo R. , Wang W.
Published: October 2010

Abstract. This contribution introduces a fractal filtering technique newly developed on the basis of a spectral energy density vs. area power-law model in the context of multifractal theory. It can be used to map anisotropic singularities of geochemical landscapes created from geochemical concentration values in various surface media such as soils, stream sediments, tills and water. A geochemical landscape can be converted into a Fourier domain in which the spectral energy density is plotted against the area (in wave number units), and the relationship between the spectrum energy density (S) and the area (A) enclosed by the above-threshold spectrum energy density can be fitted by power-law models. Mixed geochemical landscape patterns can be fitted with different S-A power-law models in the frequency domain. Fractal filters can be defined according to these different S-A models and used to decompose the geochemical patterns into components with different self-similarities. The fractal filtering method was applied to a geochemical dataset from 7,349 stream sediment samples collected from Gejiu mineral district, which is famous for its word-class tin and copper production. Anomalies in three different scales were decomposed from total values of the trace elements As, Sn, Cu, Zn, Pb, and Cd. These anomalies generally correspond to various geological features and geological processes such as sedimentary rocks, intrusions, fault intersections and mineralization.
The Northeast Asia mountain glaciers in the near future by AOGCM scenarios
Authors: Ananicheva M. D. , Krenke A. N. , Barry R. G.
Published: October 2010

Abstract. We studied contrasting glacier systems in continental (Orulgan, Suntar-Khayata and Chersky) mountain ranges, located in the region of the lowest temperatures in the Northern Hemisphere at the boundary of Atlantic and Pacific influences – and maritime ones (Kamchatka Peninsula) – under Pacific influence. Our purpose is to present a simple projection method to assess the main parameters of these glacier regions under climate change. To achieve this, constructed vertical profiles of mass balance (accumulation and ablation) based both on meteorological data for the 1950–1990s (baseline period) and ECHAM4 for 2049–2060 (projected period) are used, the latter – as a climatic scenario. The observations and scenarios were used to define the recent and future equilibrium line altitude and glacier terminus altitude level for each glacier system as well as areas and balance components. The altitudinal distributions of ice areas were determined for present and future, and they were used for prediction of glacier extent versus altitude in the system taking into account the correlation between the ELA and glacier-terminus level change. We tested two hypotheses of ice distribution versus altitude in mountain (valley) glaciers – "linear" and "non-linear". The results are estimates of the possible changes of the areas and morphological structure of northeastern Asia glacier systems and their mass balance characteristics for 2049–2060. Glaciers in the southern parts of northeastern Siberia and those covering small ranges in Kamchatka will likely disappear under the ECHAM4 scenario; the best preservation of glaciers will be on the highest volcanic peaks of Kamchatka. Finally, we compare characteristics of the stability of continental and maritime glacier systems under global warming.
Landsat TM and ETM+ derived snowline altitudes in the Cordillera Huayhuash and Cordillera Raura, Peru, 1986–2005
Authors: McFadden E. M. , Ramage J. , Rodbell D. T.
Published: October 2010

Abstract. The Cordilleras Huayhuash and Raura are remote glacierized ranges in the Andes Mountains of Peru. A robust assessment of modern glacier change is important for understanding how regional change affects Andean communities, and for placing paleo-glaciers in a context relative to modern glaciation and climate. Snowline altitudes (SLAs) derived from satellite imagery are used as a proxy for modern (1986–2005) local climate change in a key transition zone in the Andes. Clear sky, dry season Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) satellite images from 1986–2005 were used to identify snowline positions, and their altitude ranges were extracted from an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEM. Based on satellite records from 31 glaciers, mean snowline altitudes (SLAs), an approximation for the equilibrium line altitudes (ELAs), for the Cordillera Huayhuash (13 glaciers) and Cordillera Raura (18 glaciers) were 5046 m a.s.l. and 5013 m a.s.l., respectively, from 1986–2005. The rate of SLA rise was 25 m/decade in the Cordillera Huayhuash and 62 m/decade in the Cordillera Raura.
Modification of black‐body radiance at low temperatures and frequencies
Authors: Falquez C. , Hofmann R. , Baumbach T.
Published: October 2010

In contrast to earlier reports, where the spectrum of the energy density of photonic black‐body radiation modified by SU(2) effects was discussed, we discuss the low‐frequency spectrum of the radiance at temperatures ranging between 5 and 20 Kelvin. We conclude that compared to the conventional theory the only observable effect is associated with the spectral gap (total screening) which for T≥ 4.3 K scales with temperature T as ν*(T)}/GHz = 42.70 (T/K)‐0.53 + 0.21. We also discuss how a low‐temperature black body cavity under the influence of a sufficiently strong static electric field is forced to emit according to Planck's radiation law (pure U(1) theory) even at low frequencies and how this effect can be utilized to measure SU(2) induced deviations.
Salinosporamide Natural Products: Potent 20 S Proteasome Inhibitors as Promising Cancer Chemotherapeutics
Authors: Gulder Tobias A. M. , Moore Bradley S.
Published: October 2010

Proteasome inhibitors are rapidly evolving as potent treatment options in cancer therapy. One of the most promising drug candidates of this type is salinosporamide A from the bacterium Salinispora tropica. This marine natural product possesses a complex, densely functionalized γ‐lactam‐β‐lactone pharmacophore, which is responsible for its irreversible binding to its target, the β subunit of the 20S proteasome. Salinosporamide A entered phase I clinical trials for the treatment of multiple myeloma only three years after its discovery. The strong biological activity and the challenging structure of this compound have fueled intense academic and industrial research in recent years, which has led to the development of more than ten syntheses, the elucidation of its biosynthetic pathway, and the generation of promising structure–activity relationships and oncological data. Salinosporamide A thus serves as an intriguing example of the successful interplay of modern drug discovery and biomedical research, medicinal chemistry and pharmacology, natural product synthesis and analysis, as well as biosynthesis and bioengineering.
Influence of alkali fiber treatment and fiber processing on the mechanical properties of hemp/epoxy composites
Authors: Islam Mohammad S. , Pickering Kim L. , Foreman Nic J.
Published: October 2010

Industrial hemp fibers were treated with a 5 wt % NaOH, 2 wt % Na2SO3 solution at 120°C for 60 min to remove noncellulosic fiber components. Analysis of fibers by lignin analysis, scanning electron microscopy (SEM), zeta potential, Fourier transform infrared (FTIR) spectroscopy, wide angle X‐ray diffraction (WAXRD) and differential thermal/thermogravimetric analysis (DTA/TGA), supported that alkali treatment had (i) removed lignin, (ii) separated fibers from their fiber bundles, (iii) exposed cellulose hydroxyl groups, (iv) made the fiber surface cleaner, and (v) enhanced thermal stability of the fibers by increasing cellulose crystallinity through better packing of cellulose chains. Untreated and alkali treated short (random and aligned) and long (aligned) hemp fiber/epoxy composites were produced with fiber contents between 40 and 65 wt %. Although alkali treatment generally improved composite strength, better strength at high fiber contents for long fiber composites was achieved with untreated fiber, which appeared to be due to less fiber/fiber contact between alkali treated fibers. Composites with 65 wt % untreated, long aligned fiber were the strongest with a tensile strength (TS) of 165 MPa, Young's modulus (YM) of 17 GPa, flexural strength of 180 MPa, flexural modulus of 9 GPa, impact energy (IE) of 14.5 kJ/m2, and fracture toughness (KIc) of 5 MPa m1/2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Cellular compatibility of copolymer hydrogels based on site‐selectively‐modified chitosan with poly(N‐isopropyl acrylamide)
Authors: Don Trong‐Ming , Chou Shu‐Chung , Cheng Liao‐Ping , Tai Hung‐Yin
Published: October 2010

This research synthesized graft copolymers of chitosan‐g‐poly(N‐isopropyl acrylamide) (CS‐g‐PNIPAAm) by UV‐initiated free‐radical polymerization of NIPAAm monomer to CS selectively at the C‐6 position of pyranose ring. First, amino groups in CS were protected by reaction with phthalic anhydride (PA) to form PACS. The degree of phthaloylation was carefully controlled to ensure that most amino groups were protected, and only a very small amount of hydroxyl groups were reacted. In the second step, the vinyl functional group was introduced to the PACS by reaction with a vinyl compound containing an isocyanate group (3‐isopropenyl‐αα′‐dimethylbenzyl isocyanate), through the urethane linkage with hydroxyl groups at the C‐6 position. The phthaloyl groups were then removed by hydrazine to recover the amino groups in CS. Finally, PNIPAAm was grafted to the vinyl CS at the C‐6 position by UV‐initiated free‐radical polymerization. The synthesized CS‐g‐PNIPAAm copolymers were confirmed to have a structure of an AB‐crosslinked graft copolymer. Respectively, these copolymer hydrogels exhibited pH‐ and thermal‐responsive swelling properties in an aqueous solution due to their CS and PNIPAAm components. The test of cell viability with L929 fibroblast revealed that the CS‐g‐PNIPAAm copolymers having a grafting ratio lower than 1.7 had cellular compatibility as good as pure CS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Grafting of poly(ethylene glycol) monoacrylate onto polycarbonateurethane surfaces by ultraviolet radiation grafting polymerization to control hydrophilicity
Authors: Zhao Haiyang , Feng Yakai , Guo Jintang
Published: October 2010

In this study, we used a UV radiation grafting method to modify the surface of the biomaterial polycarbonateurethane (PCU). Hydrophilic poly(ethylene glycol) monoacrylate (PEGMA; number‐average molecular weight = 526) as a macromolecular monomer was grafted onto the PCU surface by UV photopolymerization. The Fourier transform infrared and X‐ray photoelectron spectroscopy results of the graft‐modified PCU confirmed poly[poly(ethylene glycol) monoacrylate] block grafting onto the surface. We investigated the effects of the reaction temperature, macromolecular monomer concentration, UV irradiation time, and photoinitiator concentration on the grafting density (GD) in detail. Furthermore, we investigated the effects of GD under various process conditions on the water uptake and water contact angle. The modified materials had a high water uptake and low water contact angle, which indicated that the hydrophilicity of the PCU surface was improved significantly by the introduction of the hydrophilic poly(ethylene glycol) blocks on the surface. The anticoagulant properties of the material might also have been improved. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Social peers rescue autism‐relevant sociability deficits in adolescent mice
Authors: Yang Mu , Perry Kayla , Weber Michael D. , Katz Adam M. , Crawley Jacqueline N.
Published: October 2010

Behavioral therapies are currently the most effective interventions for treating the diagnostic symptoms of autism. We employed a mouse model of autism to evaluate components of behavioral interventions that improve sociability in mice. BTBR T+tf/J (BTBR) is an inbred mouse strain that exhibits prominent behavioral phenotypes with face validity to all three diagnostic symptom categories of autism, including robust and well‐replicated deficits in social approach and reciprocal social interactions. To investigate the role of peer interactions in the development of sociability, BTBR juvenile mice were reared in the same home cage with juvenile mice of a highly social inbred strain, C57BL/6J (B6). Subject mice were tested as young adults for sociability and repetitive behaviors. B6 controls reared with B6 showed their strain‐typical high sociability. BTBR controls reared with BTBR showed their strain‐typical lack of sociability. In contrast, BTBR reared with B6 as juveniles showed significant sociability as young adults. A 20‐day intervention was as effective as a 40‐day intervention for improving social approach behavior. High levels of repetitive self‐grooming in BTBR were not rescued by peer‐rearing with B6, indicating specificity of the intervention to the social domain. These results from a robust mouse model of autism support the interpretation that social enrichment with juvenile peers is a beneficial intervention for improving adult outcome in the social domain. This novel paradigm may prove useful for discovering factors that are essential for effective behavioral treatments, and biological mechanisms underlying effective behavioral interventions.
Mood effects on dominated choices: Positive mood induces departures from logical rules
Authors: de Vries Marieke , Holland Rob W. , Corneille Olivier , Rondeel Eefje , Witteman Cilia L.M.
Published: October 2010

In two studies, we investigated the role of mood states in dominated behavioral choices. Past research has shown that mood effects on judgment and decision‐making can be pervasive. Yet, the role of mood in dominated choices has so far been neglected. The present research represents a first empirical examination of mood effects on dominated choices. We measured (Study 1) or manipulated (Study 2) mood states in participants who made a series of choices in a gambling game. In this choice task without trade‐offs, participants were provided with information about the outcomes and probabilities associated with each choice option. The strategy to maximize the expected mean outcome implied the application of a straightforward and logical rule: Always choose the dominant option with the highest expected value. It has been argued in the literature that mood should have little or no impact when preferences are clear or strong. Still, we expected that mood states would affect even these dominated choices, building on previous work that showed that positive mood states enhance flexibility, creativity, and explorative behavior. The results showed that decisions made in a happier mood were less often in accordance with the logical rule than decisions made in a sadder mood. To conclude, happier mood states are associated to a lesser extent with decisions in accordance with a rule‐based strategy that maximizes expected mean outcomes in dominated choices. Copyright © 2010 John Wiley & Sons, Ltd.
Experiences of supervising postgraduate community psychology students at Wits university, South Africa
Authors: Langa Malose , Graham Tanya
Published: October 2010

In this article, the authors discuss problems and challenges of supervising postgraduate community psychology students at the University of the Witwatersrand, South Africa. As part of their community work, students developed community projects in schools in Alexandra Township, aimed at dealing with social ills such as HIV/AIDS, gangs, violence, substance abuse and teenage pregnancy. Students found community work to be extremely exhausting, stressful and demanding. Therefore, community psychology supervision became an important space in helping students to reflect on the experiences, anxieties and frustrations. This article discusses key themes that have emerged in community supervision, including gender, race and class issues. In conclusion, recommendations are provided on how to improve community psychology supervision based our experiences. Supervisors need to be proactive in helping students to reflect on their experiences and actively engage with some of the theoretical and practical issues that emerge in community work. Copyright © 2010 John Wiley & Sons, Ltd.
Echocardiographically guided catheter closure of arterial ducts in small preterm infants on the neonatal intensive care unit
Authors: Bentham Jamie , Meur Saumen , Hudsmith Lucy , Archer Nick , Wilson Neil
Published: October 2010

Objective: To describe closure of haemodynamically significant arterial ducts in preterm infants using an echocardiographically guided cardiac catheter technique in selected infants in the neonatal nursery and in preference to cardiac surgery. Background: Persistently patent arterial ducts are common in preterm infants and are associated with significant morbidity and mortality. Cardiac catheter techniques continue to improve and occlusion of arterial ducts in preterm infants is becoming technically feasible. Closure of arterial ducts by cardiac catheter techniques would enable selected infants to avoid surgery and a lateral thoracotomy, as well as potentially obviating the need for transfer of sick preterm infants between units for duct closure. Methods and Results: This brief report describes placement of coils or Amplatzer duct devices to occlude arterial ducts in small premature infants exclusively under echocardiographic guidance in the Neonatal Intensive Care Unit. Conclusions: Closing arterial ducts in the neonatal nursery by an echocardiographically guided cardiac catheter technique with minimal morbidity is becoming achievable and is a significant advance in neonatal care. © 2010 Wiley‐Liss, Inc.
Control of Enantioselectivity with Flexible Biaryl Axes: Terpene‐Based Alkylzinc Catalysts in Enantioselective Dialkylzinc Additions
Authors: Leven Matthias , Schlörer Nils E. , Neudörfl Jörg M. , Goldfuss Bernd
Published: October 2010

New enantiopure pyridyl alcohols are efficiently accessible through few synthetic steps from commercially available terpenes, that is, (+)‐fenchone, (−)‐menthone and (−)‐verbenone as well as 2,6‐diphenylpyridine. These chelating pyridyl alcohols exhibit flexible pyridyl–phenylene axes, which give rise to P and M conformers. Alkylzincation of the hydroxy groups eliminates equilibria of the conformers and generates alkylzinc complexes with adjusted biaryl axes, as it is demonstrated by NMR studies. These alkylzinc catalysts perform well in the addition of dimethylzinc or diethylzinc to benzaldehyde with yields up to 99 % and ee’s up to 95 %. The adjusted pyridylphenylene conformations in the ligands now control enantioselectivities of the catalysts, which were also analysed by computations at the DFT level.
Synthesis of enantiopure trans‐N‐Boc‐3‐aminobicyclo[2.2.2]octane‐2‐carboxylic acids and their bicyclic 1,3‐amino alcohol derivatives via the [4+2] cycloaddition of 1,3‐cyclohexadiene to a chiral β‐nitroacrylate
Authors: Calmes Monique , Escale Françoise , Didierjean Claude , Martinez Jean
Published: October 2010

The chiral β‐nitroacrylate 2 derived from the (R)‐ or (S)‐4‐(3‐hydroxy‐4,4‐dimethyl‐2‐oxopyrrolidin‐1‐yl) benzoic acid 1 acts as a reactive dienophile in a diastereoselective Diels‐Alder reaction with 1,3‐cyclohexadiene. The major cycloadducts have been isolated and transformed into enantiopure trans(2S,3S)‐ or (2R,3R)‐N‐Boc‐3‐aminobicyclic[2,2,2]octane‐2‐carboxylic acids 5. The trans‐(2S,3S)‐ or (2R,3R)‐N‐Boc 3‐(hydoxymethyl)‐2‐aminobicyclic[2,2,2]octane 6 derivatives were also obtained. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
Statine. Cholesterolsenker
Authors: Schäfer Bernd
Published: October 2010

Die 3‐Hydroxy‐3‐methylglutaryl‐Coenzym‐A‐Reduktase (HMG‐ CoA‐Reduktase) katalysiert die Bildung von Mevalonsäure, einer frühen Zwischenstufe in der Biosynthese von Cholesterol. Die Statine sind HMG‐CoA‐Reduktase‐Inhibitoren, die sehr effizient die Cholesterol‐Serumwerte senken und sehr häufig zur Behandlung der Hypercholesterolämie, der Ursache der Arteriosklerose, verordnet werden. Dieser Review beschreibt den medizinischen Hintergrund dieser Krankheit, die Entdeckung der Statine, ihre Biosynthese und die Methoden der industriellen Herstellung der weltweit umsatzstärksten Arzneiwirkstoffe.
Irrungen und Wirrungen um Biokraftstoffe. Biokraftstoffe sind nicht per se nachhaltig
Authors: Kreysa Gerhard
Published: October 2010

Die jährliche Photosyntheseleistung auf der Erde übersteigt die anthropogene CO2‐Produktion. Dies legt eine energetische Nutzung der Biomasse nahe und hat die Entwicklung von Biokraftstoffen erheblich gefördert. In vielen Fällen verstößt die Nutzung von Biokraftstoffen jedoch gegen Prinzipien der Nachhaltigkeit. Für die Deckung des Weltenergiebedarfes durch Biomasse würde die gesamte verfügbare landwirtschaftliche Nutzfläche benötigt. Diese Einsicht hat eine kritische Teller‐oder‐Tank‐Diskussion ausgelöst. Energetisch und ökologisch effizienter als die Nutzung von Biokraftstoffen wäre der Anbau schnellwachsender Hölzer und deren direkte Verstromung im Kraftwerk. Die mit großem Abstand effizienteste Nutzung der Sonnenenergie erlauben Photovoltaik und Solarthermie. Wegen ihrer hohen Energiedichte werden flüssige Biokraftstoffe der zweiten Generation aber dort, wo die Elektromobilität an Grenzen stößt, auch in Zukunft Anwendung finden.
Keine Alternative für die Statine?
Authors: Schäfer Bernd
Published: October 2010

Die Standardmedikamente zur Behandlung der Arteriosklerose sind heute die Statine (siehe Seite 344ff, Statine). Es gab in der Vergangenheit viele Ansätze zur Behandlung der krankhaften Blutgefäßveränderungen, aber nur wenige waren in der klinischen Phase bisher erfolgreich. Kürzlich ließen Studien Zweifel am Einsatz des als Cholesterolsenkers verwendeten Wirkstoffs Ezetimib aufkommen.
NDM‐1: Ein neuer Sieg für multiresistente Bakterien
Authors: Welter Kira
Published: October 2010

Im Wettlauf zwischen Antibiotika und multiresistenten Bakterien ist den Mikroorganismen erneut einen Punktsieg gelungen: Forscher haben in verschiedenen Ländern Bakterien mit einem neuen Resistenzgen entdeckt, das das Enzym NDM‐1 bilden kann. Dieses Enzym ermöglicht es den Keimen, auch Reserveantibiotika, die normalerweise nur bei schweren, sonst unbehandelbaren Infektionen eingesetzt werden, unwirksam zu machen. Das NDM‐1‐Gen (blaNDM1) wurde in Darmbakterien gefunden und kann leicht von einer Bakterienart zur anderen weitergegeben werden. Die neuen NDM‐1 bildenden Keime sind bisher vereinzelt in Deutschland, England, Belgien und Schweden nachgewiesen worden. In Pakistan, Indien und Bangladesch sind sie offenbar weiter verbreitet.
Korrektur zu: Mein kleiner grüner Kaktus
Authors: Streller Sabine , Roth Klaus
Published: October 2010

Im Artikel “Mein kleiner grüner Kaktus”, der im letzten Heft erschienen ist, befindet sich auf Seite 293 ein Fehler in Abbildung 12. Das C‐3 der Ribulose 5 weist die falsche Konfiguration auf. Wir haben die Abbildung mit korrekter Formel hier noch einmal abgedruckt und bitten den Fehler zu entschuldigen. Professor Dr. Sven Doye von der Uni Oldenburg danken wir für seinen Hinweis.
Morphological changes in Daphnia galeata induced by a crustacean terpenoid hormone and its analog
Authors: Oda Shigeto , Kato Yasuhiko , Watanabe Hajime , Tatarazako Norihisa , Iguchi Taisen
Published: October 2010

Terpenoid hormones in insects (i.e., juvenile hormones) have various effects on physiology, morphology, and behavior, producing a wide range of phenotypic variation. Recent studies have shown that sex determination in cladoceran crustaceans is under the strong control of a major terpenoid hormone of crustaceans, methyl farnesoatote (MF). It can be easily conceived that MF is also a major determinant of other traits in cladocerans. In the present study, morphological changes known as antipredatory responses in a cladoceran Daphnia galeata in response to exposure to MF and a juvenile hormone-mimicking pesticide, fenoxycarb, were investigated. Morphological change was studied using neonates less than 24 h old, exposed either to MF at the concentrations from 1.9 to 30 µg/L, or fenoxycarb at the concentrations from 13 to 200 ng/L, for 6 d. Animals developed a longer helmet at 1.9 µg/L of MF and 25 ng/L of fenoxycarb, and showed a concentration-dependent elongation. However, the tail spine was reduced in size in a concentration-dependent manner. Results of the present study not only give new insight into the mechanisms of inducible defenses in cladocerans, but also provide invaluable information to understand ecological and evolutionary consequences of endocrine disruption through the shift in biological interaction between predator and prey. Environ. Toxicol. Chem. 2011;30:232–238. © 2010 SETAC
CXC chemokine receptor-1 is expressed by hepatocytes and regulates liver recovery after hepatic ischemia/reperfusion injury
Authors: Clarke Callisia , Kuboki Satoshi , Sakai Nozomu , Kasten Kevin R. , Tevar Amit D. , Schuster Rebecca , Blanchard John , Caldwell Charles C. , Edwards Michael J. , Lentsch Alex B.
Published: October 2010

CXC chemokines mediate hepatic inflammation and injury following ischemia/reperfusion (I/R). More recently, signaling through CXC chemokine receptor-2 (CXCR2) was shown to delay liver recovery and repair after I/R injury. The chemokine receptor CXCR1 shares ligands with CXCR2, yet nothing is known about its potential role in liver pathology. In the present study, we examined the role of CXCR1 in the injury and recovery responses to I/R using a murine model. CXCR1 expression was undetectable in livers of sham-operated mice. However, after ischemia CXCR1 expression increased 24 hours after reperfusion and was maximal after 96 hours of reperfusion. CXCR1 expression was localized largely to hepatocytes. In order to assess the function of CXCR1, CXCR2−/− mice were treated with the CXCR1/CXCR2 antagonist, repertaxin. Prophylactic treatment with repertaxin had no effect on acute inflammation or liver injury. However, when repertaxin was administered 24 hours postreperfusion there was a significant increase in hepatocellular injury and a delay in recovery compared to control-treated mice. CXCR1−/− mice also demonstrated delayed recovery and regeneration after I/R when compared to wild-type mice. In vitro, hepatocytes from CXCR2−/− mice that were stimulated to express CXCR1 showed increased proliferation in response to ligand. Hepatocyte proliferation was decreased in CXCR1−/− mice in vivo.

Conclusion:

This is the first report to show that CXCR1 expression is induced in hepatocytes after injury. Furthermore, the data suggest that CXCR1 has divergent effects from CXCR2 and appears to facilitate repair and regenerative responses after I/R injury. (Hepatology 2011)
A unified framework for the functional organization of the medial temporal lobes and the phenomenology of episodic memory
Authors: Ranganath Charan
Published: October 2010

There is currently an intense debate about the nature of recognition memory and about the roles of medial temporal lobe subregions in recognition memory processes. At a larger level, this debate has been about whether it is appropriate to propose unified theories to explain memory at neural, functional, and phenomenological levels of analysis. Here, I review findings from physiology, functional imaging, and lesion studies in humans, monkeys, and rodents relevant to the roles of medial temporal lobe subregions in recognition memory, as well as in short‐term memory and perception. The results from these studies are consistent with the idea that there is functional heterogeneity in the medial temporal lobes, although the differences among medial temporal lobe subregions do not precisely correspond to different types of memory tasks, cognitive processes, or states of awareness. Instead, the evidence is consistent with the idea that medial temporal lobe subregions differ in terms of the kind of information they process and represent, and that these regions collectively support episodic memory by binding item and context information. © 2010 Wiley‐Liss, Inc.
Predictive, interactive multiple memory systems
Authors: Henson Richard N. , Gagnepain Pierre
Published: October 2010

Most lesion studies in animals, and neuropsychological and functional neuroimaging studies in humans, have focused on finding dissociations between the functions of different brain regions, for example in relation to different types of memory. While some of these dissociations can be questioned, particularly in the case of neuroimaging data, we start by assuming a “modal model” in which at least three different memory systems are distinguished: an episodic system (which stores associations between items and spatial/temporal contexts, and which is supported primarily by the hippocampus); a semantic system (which extracts combinations of perceptual features that define items, and which is supported primarily by anterior temporal cortex); and modality‐specific perceptual systems (which represent the sensory features extracted from a stimulus, and which are supported by higher sensory cortices). In most situations however, behavior is determined by interactions between these systems. These interactions reflect the flow of information in both “forward” and “backward” directions between memory systems, where backward connections transmit predictions about the current item/features based on the current context/item. Importantly, it is the resulting “prediction error”—the difference between these predictions and the forward transmission of sensory evidence—that drives memory encoding and retrieval. We describe how this “predictive interactive multiple memory systems” (PIMMS) framework can be applied to human neuroimaging data acquired during encoding or retrieval phases of the recognition memory paradigm. Our novel emphasis is thus on associations rather than dissociations between activity measured in key brain regions; in particular, we propose that measuring the functional coupling between brain regions will help understand how these memory systems interact to guide behavior. © 2010 Wiley‐Liss, Inc.
The single place fields of CA3 cells: A two‐stage transformation from grid cells
Authors: de Almeida Licurgo , Idiart Marco , Lisman John E.
Published: October 2010

Granule cells of the dentate gyrus (DG) generally have multiple place fields, whereas CA3 cells, which are second order, have only a single place field. Here, we explore the mechanisms by which the high selectivity of CA3 cells is achieved. Previous work showed that the multiple place fields of DG neurons could be quantitatively accounted for by a model based on the number and strength of grid cell inputs and a competitive network interaction in the DG that is mediated by gamma frequency feedback inhibition. We have now built a model of CA3 based on similar principles. CA3 cells receive input from an average of one active DG cell and from 1,400 cortical grid cells. Based on experimental findings, we have assumed a linear interaction of the two pathways. The results show that simulated CA3 cells generally have a single place field, as observed experimentally. Thus, a two‐step process based on simple rules (and that can occur without learning) is able to explain how grid cell inputs to the hippocampus give rise to cells having ultimate spatial selectivity. The CA3 processes that produce a single place depend critically on the competitive network processes and do not require the direct cortical inputs to CA3, which are therefore likely to perform some other unknown function. © 2010 Wiley Periodicals, Inc.