bluuebunny/crossref_metadata_2025 huggingface dataset:
A Psychometric Study of the Quality Perception Questionnaire
Authors: Cioffi† Raffaele , Coluccia Anna , Ferretti Fabio , Lorini Francesca , Saggino Aristide , Furnham Adrian
Published: March 2012

The present paper reexamines the psychometric properties of the Quality Perception Questionnaire (QPQ), an Italian survey instrument measuring patients’ perceptions of the quality of a recent hospital admission experience, in a sample of 4400 patients (Mage= 56.42 years; SD = 19.71 years, 48.8% females). The 14-item survey measures four factors: satisfaction with medical doctors, nursing staff, auxiliary staff, and hospital structures. First, we tested two models using a confirmatory factor analysis (structural equation modeling): a four orthogonal factor and a four oblique factor model. The SEM fit indices and the χ² difference suggested the acceptance of the second model. We then did a simulation using a bootstrap with 1000 replications. Results confirmed the four oblique factor solution. Third, we tested whether there were significant differences with respect to age or sex. The multivariate general linear model showed no significant differences in the factors with respect to sex or age.
Multivariate Longitudinal Modeling of Cognitive Aging
Authors: Robitaille Annie , Muniz Graciela , Piccinin Andrea M. , Johansson Boo , Hofer Scott M.
Published: March 2012

We illustrate the use of the parallel latent growth curve model using data from OCTO-Twin. We found a significant intercept-intercept and slope-slope association between processing speed and visuospatial ability. Within-person correlations among the occasion-specific residuals were significant, suggesting that the occasion-specific fluctuations around individual’s trajectories, after controlling for intraindividual change, are related between both outcomes. Random and fixed effects for visuospatial ability are reduced when we include structural parameters (directional growth curve model) providing information about changes in visuospatial abilities after controlling for processing speed. We recommend this model to researchers interested in the analysis of multivariate longitudinal change, as it permits decomposition and directly interpretable estimates of association among initial levels, rates of change, and occasion-specific variation.
Perceived Rights of and Social Distance to People with Alzheimer’s Disease
Authors: Bourkel Elisabeth , Ferring Dieter , Weber Germain
Published: March 2012

The present study investigated how laypeople and professionals (N = 185) judge the rights of someone affected with Alzheimer’s disease (AD) and whether social distance exists toward this person. Participants completed a questionnaire after reading a vignette describing a target person with an early stage of AD. Half of the participants responded to a female target, the other half to a male target. Results showed that the rights and competencies of the persons are rated high and social distance is exhibited only to a minor degree, although there was a significant difference between the male and female targets. Furthermore, health professionals approved more rights than laypeople, which suggests that there is a need for more detailed information about this disease in the general population.
Reaktionen auf das Hören einer Klangschale
Authors: Thies Wolfgang
Published: March 2012

Zusammenfassung. Die meiste Literatur über Klangschalen ist praxisorientiert. Es gibt nur wenige wissenschaftliche Veröffentlichungen. Dieser Aufsatz fasst Ratschläge zur Förderung von Gesundheit und Wohlbefinden durch das Hören von Schalenklängen ebenso zusammen wie die berichteten Wirkungen. Die akustischen Eigenschaften von Klangschalen werden kurz dargestellt. Der Verfasser hat einen Hörversuch mit 60 Teilnehmern durchgeführt, denen in Einzelsitzungen eine mittelgroße tibetische Klangschale live vorgespielt wurde. Über Äußerungen der Hörer wird ausführlich berichtet. Die meisten empfanden die Klänge als angenehm wegen des langen Ausklingens, der Schwebungen und der Sanftheit. Die häufigste Wirkung war Entspannung. Eine weitere, weniger auffallende Wirkung war die Förderung der Konzentration.
Export production and its regulating factors in the West Antarctica Peninsula region of the Southern Ocean
Authors: Huang Kuan , Ducklow Hugh , Vernet Maria , Cassar Nicolas , Bender Michael L.
Published: March 2012

In connection with the Palmer LTER program, mixed layer water samples were collected during the cruise of the L.M. Gould in Jan., 2008 at 49 stations on a 20 × 100 km grid in the West Antarctica Peninsula (WAP) region of the Southern Ocean. In this study, [O2]/[Ar] ratios and the triple isotope composition of dissolved O2 were measured, and were used to estimate net community O2 production (NCP) and gross primary O2production (GPP), respectively. These estimates are further converted to carbon export production, primary production and the f‐ratio. Our measurements give NCP ranging from −3 to 76 mmol O2 m−2 day−1 (−25 to 650 mg C m−2 day−1), and GPP from 40 to 220 mmol O2 m−2 day−1 (180 to 1010 mg C m−2 day−1). The O2 NCP/GPP ratios range from −0.04 to 0.43, corresponding to f‐ratios of −0.08 to 0.83. NCP and the NCP/GPP ratio are highest in the northern coastal areas, and decrease to lower values toward the southern coastal area and the open ocean. The inshore‐offshore gradient appears to be regulated primarily by iron availability, as supported by the positive correlation between NCP and Fv/Fm ratios (r2 = 0.22, p < 0.05). Mixed layer depth (MLD) is inversely correlated with NCP (r2 = 0.21, p < 0.002) and NCP/GPP (r2 = 0.21, p < 0.02), and highest NCP occurred in the fresh water lenses probably formed from melted coastal glaciers. These results suggest that export production and the f‐ratio increase where water stratification is intensified by input of fresh meltwater, and that mixed layer stratification is the major factor regulating NCP in the inner‐shelf and coastal regions. Along‐shelf variability of phytoplankton community composition is highly correlated with NCP, i.e., NCP increases when the diatom‐dominated community in the south transitions to the cryptophyte‐dominated one in the north. A high correlation is also observed between NCP and the logarithm of the surface chlorophyll concentration (r2 = 0.72, p < 0.0001) , which makes it possible to estimate carbon export as a function of Chl a concentration in this region.
Increased CO2 loss from vegetated drained lake tundra ecosystems due to flooding
Authors: Zona Donatella , Lipson David A. , Paw U Kyaw T. , Oberbauer Steve F. , Olivas Paulo , Gioli Beniamino , Oechel Walter C.
Published: March 2012

Tundra ecosystems are especially sensitive to climate change, which is particularly rapid in high northern latitudes resulting in significant alterations in temperature and soil moisture. Numerous studies have demonstrated that soil drying increases the respiration loss from wet Arctic tundra. And, warming and drying of tundra soils are assumed to increase CO2 emissions from the Arctic. However, in this water table manipulation experiment (i.e., flooding experiment), we show that flooding of wet tundra can also lead to increased CO2 loss. Standing water increased heat conduction into the soil, leading to higher soil temperature, deeper thaw and, surprisingly, to higher CO2 loss in the most anaerobic of the experimental areas. The study site is located in a drained lake basin, and the soils are characterized by wetter conditions than upland tundra. In experimentally flooded areas, high wind speeds (greater than ∼4 m s−1) increased CO2 emission rates, sometimes overwhelming the photosynthetic uptake, even during daytime. This suggests that CO2 efflux from C rich soils and surface waters can be limited by surface exchange processes. The comparison of the CO2 and CH4 emission in an anaerobic soil incubation experiment showed that in this ecosystem, CO2 production is an order of magnitude higher than CH4 production. Future increases in surface water ponding, linked to surface subsidence and thermokarst erosion, and concomitant increases in soil warming, can increase net C efflux from these arctic ecosystems.
Sparse regularization for precipitation downscaling
Authors: Ebtehaj A. M. , Foufoula‐Georgiou E. , Lerman G.
Published: March 2012

Downscaling of remotely sensed precipitation images and outputs of general circulation models has been a subject of intense interest in hydrometeorology. The problem of downscaling is basically one of resolution enhancement, that is, appropriately adding details or high frequency features onto a low‐resolution observation or simulated rainfall field. Invoking the property of rainfall self similarity, this mathematically ill‐posed problem has been approached in the past within a stochastic framework resulting in ensemble of possible high‐resolution realizations. In this work, we recast the rainfall downscaling into an ill‐posed inverse problem and introduce a class of nonlinear estimators to properly regularize it and obtain the best high‐resolution estimate in an optimal sense. This regularization capitalizes on two main observations: (1) precipitation fields are sparse when transformed into an appropriately chosen domain (e.g., wavelet), and (2) small‐scale organized precipitation features tend to recur within and across different storm environments. We demonstrate the promise of the proposed methodology through downscaling and error analysis of level III precipitation reflectivity snapshots provided by the ground‐based next generation Doppler weather radars in a ground validation sites of the Tropical Rainfall Measuring Mission.
Changes in permeability caused by transient stresses: Field observations, experiments, and mechanisms
Authors: Manga Michael , Beresnev Igor , Brodsky Emily E. , Elkhoury Jean E. , Elsworth Derek , Ingebritsen S. E. , Mays David C. , Wang Chi‐Yuen
Published: March 2012

Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10−6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability‐limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.
Integral equation analysis of a low‐profile receiving planar microstrip antenna with a cloaking superstrate
Authors: Valagiannopoulos Constantinos A. , Tsitsas Nikolaos L.
Published: March 2012

Eliminating the electromagnetic interaction of a device with its background is a topic which attracts considerable attention both from a theoretical as well as from an experimental point of view. In this work, we analyze an infinite two‐dimensional planar microstrip antenna, excited by an incident plane wave, and propose its potential operation as a low‐profile receiving antenna, by suitably adjusting the parameters of its cloaking superstrate. We impose a semi‐analytic integral equation method to determine the scattering characteristics of the microstrip antenna. The method utilizes the explicit expressions of the Green's function of the strip‐free microstrip and yields the surface strip's current as the solution of a suitable linear system. Subsequently, the antenna's far‐field response is obtained. Numerical results are presented for the achieved low profile of the receiving antenna, by choosing suitably the cloaking superstrate parameters. It is demonstrated that for specific cloaking parameters the scattered field by the antenna is considerably reduced, while the received signal from the antenna is maintained at sensible levels. We point out that the material values achieving this reduction correspond to a superstrate filled with anϵ‐near‐zero or a low‐index metamaterial. Finally, the variations of the device reaction for various superstrates are depicted, concluding that for optimized superstrate's parameters, the reaction values are significantly reduced, while at distinct scattering angles even approach zero.
Do time‐variable tracers aid the evaluation of hydrological model structure? A multimodel approach
Authors: McMillan Hilary , Tetzlaff Doerthe , Clark Martyn , Soulsby Chris
Published: March 2012

In this paper we explore the use of time‐variable tracer data as a complementary tool for model structure evaluation. We augment the modular rainfall‐runoff modeling framework FUSE (Framework for Understanding Structural Errors) with the ability to track the age distribution of water in all model stores and fluxes. We therefore gain the novel ability to compare tracer/water age signatures measured in a catchment with those predicted using hydrological models built from components based on four existing popular models. Key modeling decisions available in FUSE are evaluated against streamflow tracer dynamics using weekly observations of tracer concentration which reflect the tracer transit time distribution (TTD). Model structure choice is shown to have a significant effect on simulated water age characteristics, even when simulated flow series are very similar. We show that for a Scottish case study catchment, careful selection of model structure enables good predictions of both streamflow and tracer dynamics. We then use FUSE as a hypothesis testing tool to understand how different model characterization of TTDs and mean transit times affect multicriteria model performance. We demonstrate the importance of time variation in TTDs in simulating water movement along fast flow pathways, and investigate sensitivity of the models to assumptions about our ability to sample fast, near‐surface flow.
Earth‐based detection of Uranus' aurorae
Authors: Lamy L. , Prangé R. , Hansen K. C. , Clarke J. T. , Zarka P. , Cecconi B. , Aboudarham J. , André N. , Branduardi‐Raymont G. , Gladstone R. , Barthélémy M. , Achilleos N. , Guio P. , Dougherty M. K. , Melin H. , Cowley S. W. H. , Stallard T. S. , Nichols J. D. , Ballester G.
Published: March 2012

This study is based on multi‐planet multi‐wavelength observations of planetary aurorae throughout the heliosphere, acquired along the propagation path of a series of consecutive interplanetary shocks. The underlying motivation to track the shocks was to increase the probability of detection of auroral emissions at Uranus. Despite several Earth‐based attempts in the past few years, at Far‐UV (FUV) and Near‐IR (NIR) wavelengths, such emissions have never been unambiguously re‐observed since their discovery by Voyager 2 in 1986. Here, we present a campaign of FUV observations of Uranus obtained in November 2011 with the Hubble Space Telescope (HST) during active solar wind conditions. We positively identify auroral signatures in several of these HST measurements, together with some obtained in 1998, representing the first images of Uranus' aurorae. We analyze their characteristics and discuss the implications for the asymmetric Uranian magnetosphere and its highly variable interaction with the solar wind flow from near‐solstice (1986) to near‐equinox (2011) configurations.
Role of type I interferons in the activation of autoreactive B cells
Authors: Kiefer Kerstin , Oropallo Michael A , Cancro Michael P , Marshak‐Rothstein Ann
Published: March 2012

Type I interferons (IFNs) are a family of cytokines involved in the defense against viral infections that play a key role in the activation of both the innate and adaptive immune system. IFNs both directly and indirectly enhance the capacity of B lymphocytes to respond to viral challenge and produce cytotoxic and neutralizing antibodies. However, prolonged type I IFN exposure is not always beneficial to the host. If not regulated properly IFN can drive autoantibody production as well as other parameters of systemic autoimmune disease. Type I IFNs impact B‐cell function through a variety of mechanisms, including effects on receptor engagement, Toll‐like receptor expression, cell migration, antigen presentation, cytokine responsiveness, cytokine production, survival, differentiation and class‐switch recombination. Type I IFNs are also cytotoxic for a variety of cell types and thereby contribute to the accumulation of cell debris that serves as a potential source for autoantigens. Type I IFN engagement of a variety of accessory cells further promotes B‐cell survival and activation, as exemplified by the capacity of type I IFNs to increase the level of B‐cell survival factors, such as B lymphocyte stimulator, produced by dendritic cells. Therefore, it is not surprising that the loss of expression of the type I IFN receptor can have dramatic effects on the production of autoantibodies and on the clinical features of systemic autoimmune diseases such as systemic lupus erythematosus.
CARM1/PRMT4 is necessary for the glycogen gene expression programme in skeletal muscle cells
Authors: Wang Shu-Ching Mary , Dowhan Dennis H. , Eriksson Natalie A. , Muscat George E. O.
Published: March 2012

CARM1 (co-activator-associated arginine methyltransferase 1)/PRMT4 (protein arginine methyltransferase 4), functions as a co-activator for transcription factors that are regulators of muscle fibre type and oxidative metabolism, including PGC (peroxisome-proliferator-activated receptor γ co-activator)-1α and MEF2 (myocyte enhancer factor 2). We observed significantly higher Prmt4 mRNA expression in comparison with Prmt1–Prmt6 mRNA expression in mouse muscle (in vitro and in vivo). Transfection of Prmt4 siRNA (small interfering RNA) into mouse skeletal muscle C2C12 cells attenuated PRMT4 mRNA and protein expression. We subsequently performed additional qPCR (quantitative PCR) analysis (in the context of metabolism) to examine the effect of Prmt4 siRNA expression on >200 critical genes that control (and are involved in) lipid, glucose and energy homoeostasis, and circadian rhythm. This analysis revealed a strikingly specific metabolic expression footprint, and revealed that PRMT4 is necessary for the expression of genes involved in glycogen metabolism in skeletal muscle cells. Prmt4 siRNA expression selectively suppressed the mRNAs encoding Gys1 (glycogen synthase 1), Pgam2 (muscle phosphoglycerate mutase 2) and Pygm (muscle glycogen phosphorylase). Significantly, PGAM, PYGM and GYS1 deficiency in humans causes glycogen storage diseases type X, type V/McArdle's disease and type 0 respectively. Attenuation of PRMT4 was also associated with decreased expression of the mRNAs encoding AMPK (AMP-activated protein kinase) α2/γ3 (Prkaa2 and Prkag3) and p38 MAPK (mitogen-activated protein kinase), previously implicated in Wolff–Parkinson–White syndrome and Pompe Disease (glycogen storage disease type II). Furthermore, stable transfection of two PRMT4-site-specific (methyltransferase deficient) mutants (CARM1/PRMT4 VLD and CARM1E267Q) significantly repressed the expression of Gys1, Pgam2 and AMPKγ3. Finally, in concordance, we observed increased and decreased glycogen levels in PRMT4 (native)- and VLD (methylation deficient mutant)-transfected skeletal muscle cells respectively. This demonstrated that PRMT4 expression and the associated methyltransferase activity is necessary for the gene expression programme involved in glycogen metabolism and human glycogen storage diseases.
Metabolism of γ-hydroxybutyrate in perfused rat livers
Authors: Zhang Guo-Fang , Sadhukhan Sushabhan , Ibarra Rafael A. , Lauden Stephanie M. , Chuang Chia-Ying , Sushailo Sophia , Chatterjee Priya , Anderson Vernon E. , Tochtrop Gregory P. , Brunengraber Henri
Published: March 2012

GHB (γ-hydroxybutyrate) is both a neurotransmitter and a drug of abuse (date-rape drug). We investigated the catabolism of this compound in perfused rat livers. Using a combination of metabolomics and mass isotopomer analysis, we showed that GHB is metabolized by multiple processes, in addition to its previously reported metabolism in the citric acid cycle via oxidation to succinate. A substrate cycle operates between GHB and γ-aminobutyrate via succinic semialdehyde. Also, GHB undergoes (i) β-oxidation to glycolyl-CoA+acetyl-CoA, (ii) two parallel processes which remove C-1 or C-4 of GHB and form 3-hydroxypropionate from C-2+C-3+C-4 or from C-1+C-2+C-3 of GHB, and (iii) degradation to acetyl-CoA via 4-phosphobutyryl-CoA. The present study illustrates the potential of the combination of metabolomics and mass isotopomer analysis for pathway discovery.
Are We Making a Better World with Icts? Reflections on a Future Agenda for the IS Field
Authors: Walsham Geoff
Published: March 2012

Dramatic changes in context have occurred over the last 25 years for those of us working in the information systems (IS) field, with ICTs becoming pervasive in many areas of human activity and in all countries of the world. It is ironic that the success of ICTs has led to concerns that the distinct research contribution of the IS field could become lost and that the field itself may decline. The literature over the last decade or so has offered different and sometimes opposing suggestions as to how the field should respond to these concerns. In this paper, I discuss these debates and I use the discussion as a basis for putting forward a skeleton future agenda for the IS field as a whole. This agenda emphasises the need for a focus on ethical goals, increased use of critical approaches, welcoming other disciplines with open arms, widening our field of study to many nontraditional settings and rejecting a dominant methodological paradigm.
Women in Waiting? Singlehood, Marriage, and Family in Singapore
Authors: Ramdas Kamalini
Published: March 2012

The author engages with narratives of graduate single Indian Singaporean women based in global cities for work, namely Singapore, Melbourne, and London. She interrogates how and why these single women are often portrayed as incomplete, occupying a cusp where they are perceived as waiting for marriage. The author makes use of secondary data and twenty-nine in-depth interviews with women based overseas and in Singapore to examine critically discourses of family, marriage, and ‘singlehood’. She contests how single Indian women are constructed as ‘women in waiting’, and the hegemonic constructions of marriage and family that underlie such a discourse of waiting. By examining the experiences of the women in multiple cities, the author reveals how the women's experiences of singlehood disrupt discourses of waiting emerging from the context of the Singaporean state, Singapore-Indian community and their parents. Specifically, it is argued that singlehood cannot be understood without reference to the family, and a case is made for engaging in a politics of waiting which shows how gender, sexuality, and heteronormativity enable and constrain single Indian women's lives in Singapore and abroad, through the use of ‘punctuations’. The author thus shows how singlehood is constituted as a struggle between state, community, family, and the individual across space and time.
Variation in the whiteness and brightness of white Australian cashmere associated with farm of origin and fibre attributes
Authors: McGregor B. A.
Published: March 2012

While white cashmere is preferred by processors, its whiteness and brightness is affected by country of origin, amino acid composition, nutrition and cashmere production of goats. This work aimed to quantify the factors which affect the whiteness and brightness of 36 batches of processed Australian white cashmere sourced from nine different farms. The cashmere was tested for tristimulus values brightness (Y) and whiteness, as measured by yellowness (Y-Z). Linear models, relating Y and Y-Z were fitted to farm of origin and other objective measurements. Mean attributes (range) were: mean fibre diameter, 16.9 µm (13.9–20.4 μm); fibre curvature, 45°/mm (31–59°/mm); clean washing yield, 91.3% (79.5–97.3%); Y, 78.7 (74.7–82.2); Y-Z, 11.9 (10.3–13.6). Farm alone accounted for 72% of the variation in Y and 65% of the variation in Y-Z (P < 0.001). Once farm had been taken into account only fibre curvature (P = 0.003) was significant in predicting Y and only clean washing yield (P = 0.047) affected Y-Z. Neither the proportion of the fleece present as guard hair (clean cashmere yield) nor cashmere staple length was a significant determinant of Y or Y-Z. For each 10°/mm increase in fibre curvature Y increased 1.3 units. For each 10% increase in clean washing yield Y-Z declined 0.9 units. Variations in Y and Y-Z among farms were probably related to differences in geographic and climatic conditions and were significantly correlated to cashmere production. The effect of clean washing yield was probably related to a reduction in suint content.
Synthesis of Cyclic Carbonate From Carbon Dioxide and Epoxide Using Amino Acid Ionic Liquid Under 1atm Pressure
Authors: Gong Qing , Luo Huadong , Cao Jin , Shang Yuhan , Zhang Haibo , Wang Wenjing , Zhou Xiaohai
Published: March 2012

Herein, we report an effective synthesis of cyclic carbonates by cycloaddition of carbon dioxide to epoxide using a modified amino acid ionic liquid as catalyst under 1 atm pressure. With triethylamine as co-catalyst, the catalytic activity of the l-proline based ionic liquid was greatly enhanced, and up to 97 % isolated yield of cyclic carbonate was achieved at 90°C under atmospheric pressure without organic solvent and metal component.
Leaf structural responses to pre-industrial, current and elevated atmospheric [CO2] and temperature affect leaf function in Eucalyptus sideroxylon
Authors: Smith Renee A. , Lewis James D. , Ghannoum Oula , Tissue David T.
Published: March 2012

Leaf structure and chemistry both play critical roles in regulating photosynthesis. Yet, a key unresolved issue in climate change research is the role of changes in leaf structure in photosynthetic responses to temperature and atmospheric CO2 concentration ([CO2]), ranging from pre-industrial to future levels. We examined the interactive effects of [CO2] (290, 400 and 650 μL L–1) and temperature (ambient, ambient +4°C) on leaf structural and chemical traits that regulate photosynthesis in Eucalyptus sideroxylon A.Cunn. ex Woolls. Rising [CO2] from pre-industrial to elevated levels increased light-saturated net photosynthetic rates (Asat), but reduced photosynthetic capacity (Amax). Changes in leaf N per unit area (Narea) and the number of palisade layers accounted for 56 and 14% of the variation in Amax, respectively, associated with changes in leaf mass per area. Elevated temperature increased stomatal frequency, but did not affect Amax. Further, rising [CO2] and temperature generally did not interactively affect leaf structure or function. These results suggest that leaf Narea and the number of palisade layers are the key chemical and structural factors regulating photosynthetic capacity of E. sideroxylon under rising [CO2], whereas the lack of photosynthetic responses to elevated temperature may reflect the limited effect of temperature on leaf structure and chemistry.
Effect of asynchronous transfer on bovine embryonic development and relationship with early cycle uterine proteome profiles
Authors: Ledgard A. M. , Berg M. C. , McMillan W. H. , Smolenski G. , Peterson A. J.
Published: March 2012

The uterus provides the nurturing environment that supports the growth of the early preimplantation bovine conceptus. To determine critical time points of uterine influence, in vitro-produced Day 7 blastocysts were transferred into synchronous (Day 7) uteri and asynchronous uteri (Days 5 or 9). Embryo growth was evaluated 7 and 15 days after transfer and compared with that of embryos generated by AI. Conceptuses recovered from asynchronous Day 9 transfers were fourfold larger than synchronous transfer or gestational Day 14 AI conceptuses; by 15 days after transfer, differences were less marked. Two-dimensional gel electrophoresis was used to compare the histotroph protein composition of uterine luminal flushings (ULF) on Days 5 and 9 after oestrous to determine any protein differences that would promote embryo growth. The ULF were collected by serially flushing the uteri of the same heifers and mature cows at different times of the cycle. Ten proteins that differed in abundance between Day 5 and 9 were identified by mass spectrometry. Three, namely phosphoserine aminotransferase 1, purine nucleoside phosphorylase and aldose reductase, were verified by western blot analysis as more abundant on Day 9 (P < 0.002). Myostatin was present in only in Day 9 ULF, whereas tissue inhibitor of matrix metalloproteinase 2 (TIMP2) and legumain were only detected in Day 14 ULF. Although mature cows had lower progesterone concentrations on Days 5 and 14 (P < 0.05) and tended to have less TIMP2 than heifer groups, no other protein differences were detected. Thus, the embryo growth-enhancing environment on Day 9 was associated with temporal changes in the expression of several proteins of the histotroph.
Identification and immunolocalisation of melatonin MT1 and MT2 receptors in Rasa Aragonesa ram spermatozoa
Authors: Casao Adriana , Gallego Margarita , Abecia José Alfonso , Forcada Fernando , Pérez-Pé Rosaura , Muiño-Blanco Teresa , Cebrián-Pérez José Álvaro
Published: March 2012

The reproductive seasonality of sheep suggests that melatonin receptors may be present in ram spermatozoa. The present study confirms the presence of melatonin MT1 and MT2 receptors. The MT1 receptor was detected using immunocytochemistry, with four sperm subpopulations identified based on the following labelling patterns: (1) one small subpopulation with labelling over the entire head and tail; (2) one of two main subpopulations that exhibited reactivity at the equatorial, post-acrosomal, neck and tail regions; (3) another main subpopulation with equatorial and tail labelling only; and (4) a subpopulation in which staining was detected only in the tail. Immunocytochemistry revealed the presence of the melatonin MT2 receptor, with intense staining on the acrosome, post-acrosomal region and neck and tail regions of all cells, but not in the equatorial region. Western blot identification of ram protein extracts revealed a 39-kDa band compatible with both MT1 and MT2 receptors, a 75-kDa band compatible with MT1/MT2 heterodimerisation, a 32-kDa band compatible with MT1 receptor activation and a double band of 45–55 kDa that is compatible with MT2 receptor homodimerisation or heterodimerisation with other G-proteins. In conclusion, we provide evidence of the presence of MT1 and MT2 receptors in ram spermatozoa, although the biochemical pathway triggered by these receptors and their function in terms of fertility remains to be elucidated.
Determination of anti-Müllerian hormone concentrations in blood as a tool to select Holstein donor cows for embryo production: from the laboratory to the farm
Authors: Rico Charlène , Drouilhet Laurence , Salvetti Pascal , Dalbiès-Tran Rozenn , Jarrier Peggy , Touzé Jean-Luc , Pillet Elodie , Ponsart Claire , Fabre Stéphane , Monniaux Danielle
Published: March 2012

High between-animal variability in the number of embryos produced by multiple ovulation and embryo transfer (MOET) and ovum pick-up and in vitro production (OPU–IVP) methods remains a major limit to the development of embryo biotechnologies in cattle. The measurement of anti-Müllerian hormone (AMH) endocrine concentrations in cows can help to predict their follicular and ovulatory responses to gonadotrophin treatment. The present study aimed to provide practical information for a simple prognostic method based on AMH measurement in Holstein cows. Accurate AMH concentrations could be measured with ELISA in blood or plasma. In cows undergoing repeated OPU protocols over 1 year, the AMH concentrations measured in plasma samples collected before each gonadotrophin treatment were found to be highly repeatable and were tightly correlated with follicular responses. From data obtained at both an experimental station and farm settings, it was possible to propose AMH cut-off values to identify low-responding cows. Gonadotrophin-stimulated cows producing fewer than 15 large follicles at oestrus and fewer than 10 embryos in MOET protocols could be discarded efficiently with plasma AMH concentrations below 87 and 74 pg mL–1, respectively. In conclusion, we propose a prognostic method based on a single AMH measurement to improve the results of embryo biotechnologies.
Nutritional ecology of essential fatty acids: an evolutionary perspective
Authors: Hulbert A. J. , Abbott Sarah K.
Published: March 2012

There are four types of fatty acids but only two types are essential nutritional requirements for many animals. These are the omega-6 polyunsaturated fatty acids (n-6 PUFA) and the omega-3 polyunsaturated fatty acids (n-3 PUFA) and because they cannot be converted to one another they are separate essential dietary requirements. They are only required in small amounts in the diet and their biological importance stems largely from their role as constituents of membrane lipids. They are synthesised by plants and, as a generalisation, green leaves are the source of n-3 PUFA while seeds are the source of n-6 PUFA in the food chain. While the fatty acid composition of storage fats (triglycerides) is strongly influenced by dietary fatty acid composition, this is not the case for membrane fats. The fatty acid composition of membrane lipids is relatively unresponsive to dietary fatty acid composition, although n-3 PUFA and n-6 PUFA can substitute for each in membrane lipids to some extent. Membrane fatty acid composition appears to be regulated and specific for different species. The role of essential fats in the diet of animals on (1) basal metabolic rate, (2) thermoregulation, (3) maximum longevity, and (4) exercise performance is discussed.
Molecular crowding creates traffic jams of kinesin motors on microtubules
Authors: Leduc Cécile , Padberg-Gehle Kathrin , Varga Vladimír , Helbing Dirk , Diez Stefan , Howard Jonathon
Published: March 2012

Despite the crowdedness of the interior of cells, microtubule-based motor proteins are able to deliver cargoes rapidly and reliably throughout the cytoplasm. We hypothesize that motor proteins may be adapted to operate in crowded environments by having molecular properties that prevent them from forming traffic jams. To test this hypothesis, we reconstituted high-density traffic of purified kinesin-8 motor protein, a highly processive motor with long end-residency time, along microtubules in a total internal-reflection fluorescence microscopy assay. We found that traffic jams, characterized by an abrupt increase in the density of motors with an associated abrupt decrease in motor speed, form even in the absence of other obstructing proteins. To determine the molecular properties that lead to jamming, we altered the concentration of motors, their processivity, and their rate of dissociation from microtubule ends. Traffic jams occurred when the motor density exceeded a critical value (density-induced jams) or when motor dissociation from the microtubule ends was so slow that it resulted in a pileup (bottleneck-induced jams). Through comparison of our experimental results with theoretical models and stochastic simulations, we characterized in detail under which conditions density- and bottleneck-induced traffic jams form or do not form. Our results indicate that transport kinesins, such as kinesin-1, may be evolutionarily adapted to avoid the formation of traffic jams by moving only with moderate processivity and dissociating rapidly from microtubule ends.
Exploring the proton pump and exit pathway for pumped protons in cytochrome ba3fromThermus thermophilus
Authors: Chang Hsin-Yang , Choi Sylvia K. , Vakkasoglu Ahmet Selim , Chen Ying , Hemp James , Fee James A. , Gennis Robert B.
Published: March 2012

The heme-copper oxygen reductases are redox-driven proton pumps. In the current work, the effects of mutations in a proposed exit pathway for pumped protons are examined in the ba3-type oxygen reductase fromThermus thermophilus, leading from the propionates of heme a3to the interface between subunits I and II. Recent studies have proposed important roles for His376 and Asp372, both of which are hydrogen-bonded to propionate-A of heme a3, and for Glu126II(subunit II), which is hydrogen-bonded to His376. Based on the current results, His376, Glu126II, and Asp372 are not essential for either oxidase activity or proton pumping. In addition, Tyr133, which is hydrogen-bonded to propionate-D of heme a3, was also shown not to be essential for function. However, two mutations of the residues hydrogen-bonded to propionate-A, Asp372Ile and His376Asn, retain high electron transfer activity and normal spectral features but, in different preparations, either do not pump protons or exhibit substantially diminished proton pumping. It is concluded that either propionate-A of heme a3or possibly the cluster of groups centered about the conserved water molecule that hydrogen-bonds to both propionates-A and -D of heme a3is a good candidate to be the proton loading site.
Ultrafast large-amplitude relocation of electronic charge in ionic crystals
Authors: Zamponi Flavio , Rothhardt Philip , Stingl Johannes , Woerner Michael , Elsaesser Thomas
Published: March 2012

The interplay of vibrational motion and electronic charge relocation in an ionic hydrogen-bonded crystal is mapped by X-ray powder diffraction with a 100 fs time resolution. Photoexcitation of the prototype material KH
2
PO
4
induces coherent low-frequency motions of the PO
4
tetrahedra in the electronically excited state of the crystal while the average atomic positions remain unchanged. Time-dependent maps of electron density derived from the diffraction data demonstrate an oscillatory relocation of electronic charge with a spatial amplitude two orders of magnitude larger than the underlying vibrational lattice motions. Coherent longitudinal optical and tranverse optical phonon motions that dephase on a time scale of several picoseconds, drive the charge relocation, similar to a soft (transverse optical) mode driven phase transition between the ferro- and paraelectric phase of KH
2
PO
4
.
Autism gene variant causes hyperserotonemia, serotonin receptor hypersensitivity, social impairment and repetitive behavior
Authors: Veenstra-VanderWeele Jeremy , Muller Christopher L. , Iwamoto Hideki , Sauer Jennifer E. , Owens W. Anthony , Shah Charisma R. , Cohen Jordan , Mannangatti Padmanabhan , Jessen Tammy , Thompson Brent J. , Ye Ran , Kerr Travis M. , Carneiro Ana M. , Crawley Jacqueline N. , Sanders-Bush Elaine , McMahon Douglas G. , Ramamoorthy Sammanda , Daws Lynette C. , Sutcliffe James S. , Blakely Randy D.
Published: March 2012

Fifty years ago, increased whole-blood serotonin levels, or hyperserotonemia, first linked disrupted 5-HT homeostasis to Autism Spectrum Disorders (ASDs). The 5-HT transporter (SERT) gene (
SLC6A4
) has been associated with whole blood 5-HT levels and ASD susceptibility. Previously, we identified multiple gain-of-function SERT coding variants in children with ASD. Here we establish that transgenic mice expressing the most common of these variants, SERT Ala56, exhibit elevated, p38 MAPK-dependent transporter phosphorylation, enhanced 5-HT clearance rates and hyperserotonemia. These effects are accompanied by altered basal firing of raphe 5-HT neurons, as well as 5HT
1A
and 5HT
2A
receptor hypersensitivity. Strikingly, SERT Ala56 mice display alterations in social function, communication, and repetitive behavior. Our efforts provide strong support for the hypothesis that altered 5-HT homeostasis can impact risk for ASD traits and provide a model with construct and face validity that can support further analysis of ASD mechanisms and potentially novel treatments.
Vertebrate time-tree elucidates the biogeographic pattern of a major biotic change around the K–T boundary in Madagascar
Authors: Crottini Angelica , Madsen Ole , Poux Celine , Strauß Axel , Vieites David R. , Vences Miguel
Published: March 2012

The geographic and temporal origins of Madagascar's biota have long been in the center of debate. We reconstructed a time-tree including nearly all native nonflying and nonmarine vertebrate clades present on the island, from DNA sequences of two single-copy protein-coding nuclear genes (BDNFandRAG1) and a set of congruent time constraints. Reconstructions calculated with autocorrelated or independent substitution rates over clades agreed in placing the origins of the 31 included clades in Cretaceous to Cenozoic times. The two clades with sister groups in South America were the oldest, followed by those of a putative Asian ancestry that were significantly older than the prevalent clades of African ancestry. No colonizations from Asia occurred after the Eocene, suggesting that dispersal and vicariance of Asian/Indian groups were favored over a comparatively short period during, and shortly after, the separation of India and Madagascar. Species richness of clades correlates with their age but those clades that have a large proportion of species diversity in rainforests are significantly more species-rich. This finding suggests an underlying pattern of continuous speciation through time in Madagascar's vertebrates, with accelerated episodes of adaptive diversification in those clades that succeeded radiating into the rainforests.
Prokineticin 2 is an endangering mediator of cerebral ischemic injury
Authors: Cheng Michelle Y. , Lee Alex G. , Culbertson Collin , Sun Guohua , Talati Rushi K. , Manley Nathan C. , Li Xiaohan , Zhao Heng , Lyons David M. , Zhou Qun-Yong , Steinberg Gary K. , Sapolsky Robert M.
Published: March 2012

Stroke causes brain dysfunction and neuron death, and the lack of effective therapies heightens the need for new therapeutic targets. Here we identify prokineticin 2 (PK2) as a mediator for cerebral ischemic injury. PK2 is a bioactive peptide initially discovered as a regulator of gastrointestinal motility. Multiple biological roles for PK2 have been discovered, including circadian rhythms, angiogenesis, and neurogenesis. However, the role of PK2 in neuropathology is unknown. Using primary cortical cultures, we found that PK2 mRNA is up-regulated by several pathological stressors, including hypoxia, reactive oxygen species, and excitotoxic glutamate. Glutamate-induced PK2 expression is dependent on NMDA receptor activation and extracellular calcium. Enriched neuronal culture studies revealed that neurons are the principal source of glutamate-induced PK2. Using in vivo models of stroke, we found that PK2 mRNA is induced in the ischemic cortex and striatum. Central delivery of PK2 worsens infarct volume, whereas PK2 receptor antagonist decreases infarct volume and central inflammation while improving functional outcome. Direct central inhibition of PK2 using RNAi also reduces infarct volume. These findings indicate that PK2 can be activated by pathological stimuli such as hypoxia-ischemia and excitotoxic glutamate and identify PK2 as a deleterious mediator for cerebral ischemia.
Patient sharing and population genetic structure of methicillin-resistant
Staphylococcus aureus
Authors: Ke Weixiong , Huang Susan S. , Hudson Lyndsey O. , Elkins Kristen R. , Nguyen Christopher C. , Spratt Brian G. , Murphy Courtney R. , Avery Taliser R. , Lipsitch Marc
Published: March 2012

Rates of hospital-acquired infections, specifically methicillin-resistant
Staphylococcus aureus
(MRSA), are increasingly being used as indicators for quality of hospital hygiene. There has been much effort on understanding the transmission process at the hospital level; however, interhospital population-based transmission remains poorly defined. We evaluated whether the proportion of shared patients between hospitals was correlated with genetic similarity of MRSA strains from those hospitals. Using data collected from 30 of 32 hospitals in Orange County, California, multivariate linear regression showed that for each twofold increase in the proportion of patients shared between 2 hospitals, there was a 7.7% reduction in genetic heterogeneity between the hospitals’ MRSA populations (permutation
P
value = 0.0356). Pairs of hospitals that both served adults had more similar MRSA populations than pairs including a pediatric hospital. These findings suggest that concerted efforts among hospitals that share large numbers of patients may be synergistic to prevent MRSA transmission.
Mapping patterns of long-term settlement in Northern Mesopotamia at a large scale
Authors: Menze Bjoern H. , Ur Jason A.
Published: March 2012

The landscapes of the Near East show both the first settlements and the longest trajectories of settlement systems. Mounding is a characteristic property of these settlement sites, resulting from millennia of continuing settlement activity at distinguished places. So far, however, this defining feature of ancient settlements has not received much attention, or even been the subject of systematic evaluation. We propose a remote sensing approach for comprehensively mapping the pattern of human settlement at large scale and establish the largest archaeological record for a landscape in Mesopotamia, mapping about 14,000 settlement sites—spanning eight millennia—at 15-m resolution in a 23,000-km
2
area in northeastern Syria. To map both low- and high-mounded places—the latter of which are often referred to as “tells”—we develop a strategy for detecting anthrosols in time series of multispectral satellite images and measure the volume of settlement sites in a digital elevation model. Using this volume as a proxy to continued occupation, we find a dependency of the long-term attractiveness of a site on local water availability, but also a strong relation to the relevance within a basin-wide exchange network that we can infer from our record and third millennium B.C. intersite routes visible on the ground until recent times. We believe it is possible to establish a nearly comprehensive map of human settlements in the fluvial plains of northern Mesopotamia and beyond, and site volume may be a key quantity to uncover long-term trends in human settlement activity from such a record.
Morphology of nematic and smectic vesicles
Authors: Xing Xiangjun , Shin Homin , Bowick Mark J. , Yao Zhenwei , Jia Lin , Li Min-Hui
Published: March 2012

Recent experiments on vesicles formed from block copolymers with liquid-crystalline side chains reveal a rich variety of vesicle morphologies. The additional internal order (“structure”) developed by these self-assembled block copolymer vesicles can lead to significantly deformed vesicles as a result of the delicate interplay between two-dimensional ordering and vesicle shape. The inevitable topological defects in structured vesicles of spherical topology also play an essential role in controlling the final vesicle morphology. Here we develop a minimal theoretical model for the morphology of the membrane structure with internal nematic/smectic order. Using both analytic and numerical approaches, we show that the possible low free energy morphologies include nano-size cylindrical micelles (nano-fibers), faceted tetrahedral vesicles, and ellipsoidal vesicles, as well as cylindrical vesicles. The tetrahedral vesicle is a particularly fascinating example of a faceted liquid-crystalline membrane. Faceted liquid vesicles may lead to the design of supramolecular structures with tetrahedral symmetry and new classes of nano-carriers.