bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryptorchidie acquise, testicule oscillant et autres formes secondaires de cryptorchidie
Authors: Dobremez E. , Harper L.
Published: July 2010

Si la plus grande partie des cryptorchidies est liée à une anomalie de migration testiculaire pendant la période fœtale, il existe de multiples formes secondaires. Elles sont représentées par la cryptorchidie associée à une pathologie générale, la cryptorchidie acquise, le testicule oscillant et les formes iatrogènes. Il est important de connaître et de diagnostiquer ces formes, car des lésions histologiques du testicule sont retrouvées dans toutes les situations dans lesquelles le testicule est resté, de façon prolongée, en dehors de la bourse.
Gender differences in adolescent sport participation, teasing, self‐objectification and body image concerns
Authors: Slater Amy , Tiggemann Marika
Published: July 2010

This study examined gender differences in adolescent participation in sport and physical activity, in teasing experiences specific to the physical activity domain, and the relationship between adolescent physical activity and body image. A sample of 714 adolescents (332 girls, 382 boys) aged between 12 and 16 years completed measures of participation in organised sport and other physical activities, experiences of teasing specific to sport, self‐objectification and body image. Adolescent girls participated in organised sport at a lower rate than boys, but experienced higher levels of teasing. Both girls and boys reported being teased by same‐sex peers, but in addition, girls also reported being teased by opposite‐sex peers (i.e. boys). Time spent on aesthetic physical activities was related to disordered eating symptomatology for both girls and boys. It was concluded that teasing and body image concerns may contribute to adolescent girls’ reduced rates of participation in sports and other physical activities.
Apigenin inhibits larval growth ofCaenorhabditis elegansthrough DAF‐16 activation
Authors: Kawasaki Ichiro , Jeong Myung-Hwan , Oh Bong-Kyeong , Shim Yhong-Hee
Published: July 2010

Treatment ofCaenorhabditis eleganswith apigenin, 5,7,4′‐trihydroxyflavone, induces larval growth inhibition. To understand the molecular basis of apigenin‐induced larval growth inhibition, the effects of apigenin on DAF‐16 activity were examined. DAF‐16 was activated through nuclear translocation and the mRNA level ofsod‐3, one of the known DAF‐16 target genes, was increased upon apigenin treatment. DAF‐16 activity was required for the growth inhibition, since the larval growth retardation upon apigenin treatment was suppressed indaf‐16mutants. These results indicate that apigenin acts as a stressor that activates DAF‐16, which in turn inhibits larval growth.
Greenhouse gas emissions and energy use in UK-grown short-day strawberry (Fragaria xananassa Duch) crops
Authors: WARNER D. J. , DAVIES M. , HIPPS N. , OSBORNE N. , TZILIVAKIS J. , LEWIS K. A.
Published: July 2010

Reducing greenhouse gas emissions and optimizing energy consumption are important for mitigating climate change and improving resource use efficiency. Strawberry (Fragaria xananassa Duch) crops are a key component of the UK soft fruit sector and potentially resource-intensive crops. This is the first study to undertake a detailed environmental impact assessment of all methods of UK strawberry production. A total of 14 systems with six additional sub-systems grown for between 1 and 3 years were identified. They were defined by the growing of short-day (Junebearer) or everbearer varieties, organic production, covering with polytunnels or grown in the open, soil-grown (with or without fumigation) or container-grown (with peat or coir substrate) and summer or spring planted. Pre-harvest, the global warming potential varied between 1·5 and 10·3 t CO2 equiv/ha/crop or 0·13 and 1·14 t CO2 equiv/t of class 1 fruit. Key factors included the use of tunnels, mulch and irrigation, sterilization of soil with fumigants and the use of peat substrate. Seasonal crops without covers grown where rotation of sufficient length reduced Verticillium (system 4) were the most efficient. System 4a (that did not use mulch) emitted 0·13 t CO2 equiv/t of class 1 fruit. A second or third cropping year in soil-grown systems prolonged the effect of mulch and soil fumigants. Greenhouse gases from system 4 (with mulch) averaged 0·30 t CO2 equiv/t of class 1 fruit after 3 years of cropping compared to 0·63 and 0·36 t CO2 equiv/t after 1 and 2 years, respectively.
Two-dimensional potential flow solutions with separation
Authors: VERHOFF A.
Published: July 2010

A procedure for constructing two-dimensional incompressible potential flowfield solutions with separation and a recirculation region is presented. It naturally makes use of complex variable theory and other analysis techniques such as conformal mapping and the generalized Poisson integral formula. Flowfield determination is reduced to solution of a boundary value problem in various simple domains. The entire velocity field is described analytically; stream function and velocity potential contour maps are readily constructed. Example solutions are presented. Solutions for sharp leading edge airfoils at arbitrary angle of attack are completely determined, including the limiting angle of attack for upper-surface flow re-attachment. For other configurations (e.g. circular cylinder, backward-facing step) the analytical solution contains one or more free parameters, whose values may be inferred from boundary layer theory or experiment.
Particle focusing in a suspension flow through a corrugated tube
Authors: HEWITT G. F. , MARSHALL J. S.
Published: July 2010

A computational study is performed of the transport of a particulate suspension through a corrugated tube using a discrete-element method (DEM). The tube is axisymmetric with a radius that varies sinusoidally along the tube length, which, in the presence of a mean suspension flow, leads to periodic inward and outward acceleration of the advected particles. The oscillations in radial acceleration and straining rate lead to a net radial drift, with mean acceleration measuring about an order of magnitude smaller than the instantaneous radial acceleration, which over time focuses small particles within the tube. The foundations of particle focusing in this flow are examined analytically using lubrication theory, together with a low-Stokes-number approximation for the particle drift. This lubrication-theory solution provides the basic scaling for how the particle drift will vary with wave amplitude and wavelength. Computations are then performed using a finite-volume method for a fluid flow in the tube at higher Reynolds numbers over a range of amplitudes, wavelengths and Reynolds numbers, examining the effect of each of these variables on the averaged radial fluid acceleration. A DEM is used to simulate particle behaviour at finite Stokes numbers, and the results are compared to an asymptotic approximation valid for low Stokes numbers. At low tube Reynolds number (e.g.Re= 10), the drift velocity induced by the tube corrugations focuses the particles onto the tube centreline, in accordance with the low-Stokes-number approximation based on the axial-averaged fluid radial acceleration. At higher tube Reynolds numbers (e.g.Re= 100), the correlation between the particle radial oscillation and the fluid acceleration field leads the outermost particles to drift into a ring at a finite radius from the tube centre, with little net motion of the particles in the innermost part of the tube. At larger Stokes numbers, particles can be dispersed to the outer regions of the tube due to particle outward dispersion from the large instantaneous radial acceleration. The effects of eddy formation within the corrugation crests on particle focusing are also examined.
Activity in vitro of fungal conidia of Duddingtonia flagrans and Monacrosporium thaumasium on Haemonchus contortus infective larvae
Authors: Silva A.R. , Araújo J.V. , Braga F.R. , Alves C.D.F. , Frassy L.N.
Published: July 2010

The objective of this work was to evaluate the predatory activity of the fungi Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34a) on Haemonchus contortus infective larvae (L3) in two experimental assays (A and B). In assay A, two treatments and one control were formed and kept for 7 days in Petri dishes with 2% water-agar. Each treatment consisted of 1000 H. contortus L3 and 1000 conidia of only one fungal isolate, and the control group consisted of 1000 L3, without fungus, with 10 repetitions per group. In assay B, 1000 conidia of one of the fungal isolates, AC001 or NF34a, were added to coprocultures made from 20 g of faeces collected from sheep naturally infected with H. contortus. At the end of the experiment, the Baermann method was used to count the non-predated larvae of all Petri dishes from treatment and control groups. In assay A, no difference was observed (P>0.05) between the groups treated with AC001 and NF34a fungi. A difference was observed (P < 0.05) between the treated and control groups. The L3 reduction percentages at the end of the experiment were 87.75 and 85.57%, respectively, for the fungal isolates compared to the control group. In assay B, the reduction percentages for conidia of these isolates were 85.82 and 87.32%, respectively. The results obtained show that D. flagrans (AC001) and M. thaumasium (NF34a) were effective in the in vitro control of sheep H. contortus L3 and could be used in the biological control of this nematode.
Effect ofCrotalus viridis viridissnake venom on the ultrastructure and intracellular survival ofTrypanosoma cruzi
Authors: ADADE CAMILA M. , CONS BRUNO LEMOS , MELO PAULO A. , SOUTO-PADRÓN THAÏS
Published: July 2010

Chagas' disease, caused byTrypanosoma cruzi, affects 16–18 million people in Central and South America. Patient treatment is based on drugs that have toxic effects and limited efficacy. Therefore, new chemotherapeutic agents need to be developed. Snake venoms are sources of natural compounds used in various medical treatments. We observed thatCrotalus viridis viridisvenom was effective against all developmental forms ofT. cruzi.Ultrastructural analysis revealed swelling of mitochondria, blebbing and disruption of the plasma membrane, loss of cytoplasm components and morphological changes of the cell. Staining with propidium iodide and rhodamine 123 confirmed the observed alterations in the plasma and mitochondrial membranes, respectively. The effects of the venom on the parasite intracellular cycle were also analysed. Pre-infected LLC-MK2cells incubated withCvvvenom showed a 76–93% reduction in the number of parasites per infected cell and a 94–97·4% reduction in the number of parasites per 100 cells after 96 h of infection. Free trypomastigotes harvested from the supernatants ofCvvvenom-treated cells were incapable of initiating a new infection cycle. Our data demonstrate thatCvvvenom can access the host cell cytoplasm at concentrations that cause toxicity only to the amastigote forms ofT. cruzi, and yields altered parasites with limited infective capacity, suggesting the potential use ofCvvvenom in Chagas' disease chemotherapy.
Influence of host reproductive state onSphaerothecum destruensprevalence and infection level
Authors: ANDREOU D. , HUSSEY M. , GRIFFITHS S. W. , GOZLAN R. E.
Published: July 2010

Sphaerothecum destruensis an obligate intracellular parasite with the potential to cause high mortalities and spawning inhibition in the endangered cyprinidLeucaspius delineatus. We investigated the influence ofL. delineatus’s reproductive state on the prevalence and infection level ofS. destruens. A novel real time quantitative polymerarse chain reaction (qPCR) was developed to determineS. destruens’ prevalence and infection level. These parameters were quantified and compared in reproductive and non-reproductiveL. delineatus. The detection limit of theS. destruensspecific qPCR was determined to be 1 pg of purifiedS. destruensgenomic DNA. Following cohabitation in the lab, reproductiveL. delineatushad a significantly higherS. destruensprevalence (P<0·05) and infection levels (P<0·01) compared to non-reproductiveL. delineatus. S. destruensprevalence was 19% (n=40) in non-reproductiveL. delineatusand 41% (n=32) in reproductiveL. delineatus. However, there was no difference inS. destruensprevalence in reproductive and non-reproductive fish under field conditions. Mean infection levels were 18 and 99 pgS. destruensDNA per 250 ngL. delineatusDNA for non-reproductive and reproductiveL. delineatusrespectively. The present work indicates thatS. destruensinfection inL. delineatuscan be influenced by the latter's reproductive state and provides further support for the potential adverse impact ofS. destruenson the conservation ofL. delineatuspopulations.
Fitness and virulence of a bacterial endoparasite in an environmentally stressed crustacean host
Authors: COORS ANJA , DE MEESTER LUC
Published: July 2010

Host-parasite interactions are shaped by the co-evolutionary arms race of parasite virulence, transmission success as well as host resistance and recovery. The virulence and fitness of parasites may depend on host condition, which is mediated, for instance, by host energy constraints. Here, we investigated to what extent stress imposed by predation threat and environmental pollutants influences host-parasite interactions. We challenged the crustacean hostDaphnia magnawith the sterilizing bacterial endoparasitePasteuria ramosaand simultaneously exposed the host to fish kairomones, the pesticide carbaryl or both stressors. While parasite virulence, measured as impact on host mortality and sterilization, increased markedly after short-term pesticide exposure, it was not influenced by predation threat. Parasite fitness, measured in terms of produced transmission stages, decreased both in fish and pesticide treatments. This effect was much stronger under predation threat than carbaryl exposure, and was attributable to reduced somatic growth of the host, presumably resulting in fewer resources for parasite development. While the indirect impact of both stressors on spore loads provides evidence for host condition-dependent parasite fitness, the finding of increased virulence only under carbaryl exposure indicates a stronger physiological impact of the neurotoxic chemical compared with the effect of a non-toxic fish kairomone.
Mental and personality disorders and abstinence from alcohol: results from a national household survey
Authors: Skogen J. C. , Mykletun A. , Ferri C. P. , Bebbington P. , Brugha T. , Coid J. , Meltzer H. , Stewart R.
Published: July 2010

Background

The beneficial outcomes associated with moderate compared with low alcohol intake or abstinence may be due to the inclusion of people as ‘low consumers’, who have stopped consumption because of poor health. We investigated the association between alcohol abstinence and symptoms of common mental disorder and personality disorder, distinguishing between lifelong abstinence and abstinence following previous consumption.

Method

Analyses were based on the British National Survey of Psychiatric Morbidity 2000, which sampled 8580 residents aged 16–74 years. Hazardous drinking (Alcohol Use Disorders Identification Test) was excluded. Symptoms of common mental disorder (depression/anxiety) were identified by the Clinical Interview Schedule. The screening questionnaire of the Structured Clinical Interview for Axis II Personality Disorders was used to identify potential personality disorder. Self-reported alcohol abstinence was divided into lifelong abstinence and previous consumption. Previous consumers were asked why they had stopped. Covariates included socio-economic status, social activity and general health status.

Results

After adjustment, alcohol abstinence was associated with both common mental disorder symptoms and any personality disorder, but only for previous consumers, in whom odds ratios were 1.69 (95% CI 1.23–2.32) and 1.45 (95% CI 1.09–1.94). Associations were non-specific, being apparent for most individual mental disorder symptoms and personality disorder categories. More detailed analysis indicated that associations were again limited to previous consumers who reported ceasing alcohol consumption for health reasons.

Conclusions

Worse mental health in low alcohol consumers, particularly those who have previously ceased for health reasons, should be taken into account when interpreting associations between moderate (compared with low) alcohol consumption and beneficial health outcomes.
A meta-analysis of the risk for psychotic disorders among first- and second-generation immigrants
Authors: Bourque F. , van der Ven E. , Malla A.
Published: July 2010

Background

There is increasing acceptance of migration as a risk factor for schizophrenia and related disorders; however, the magnitude of the risk among second-generation immigrants (SGIs) remains unclear. Generational differences in the incidence of psychotic disorders among migrants might improve our understanding of the relationship between migration, ethnicity and psychotic disorders. This meta-analysis aimed at determining the risk of psychotic disorders among SGIs in comparison with non-migrants and first-generation immigrants (FGIs).

Method

Medline, EMBASE and PsycINFO databases were searched systematically for population-based studies on migration and psychotic disorders published between 1977 and 2008. We also contacted experts, tracked citations and screened bibliographies. All potential publications were screened by two independent reviewers in a threefold process. Studies were included in the meta-analysis if they reported incidence data, differentiated FGIs from SGIs and provided age-adjusted data. Data extraction and quality assessment were conducted for each study.

Results

Twenty-one studies met all inclusion criteria. A meta-analysis of 61 effect sizes for FGIs and 28 for SGIs yielded mean-weighted incidence rate ratios (IRRs) of 2.3 [95% confidence interval (CI) 2.0–2.7] for FGIs and 2.1 (95% CI 1.8–2.5) for SGIs. There was no significant risk difference between generations, but there were significant differences according to ethno-racial status and host country.

Conclusions

The increased risk of schizophrenia and related disorders among immigrants clearly persists into the second generation, suggesting that post-migration factors play a more important role than pre-migration factors or migrationper se. The observed variability suggests that the risk is mediated by the social context.
Changes in Parental Assets and Children's Educational Outcomes
Authors: LOKE VERNON , SACCO PAUL
Published: July 2010

Several countries, including Canada, Singapore and the United Kingdom, have enacted asset-based policies for children in recent years. The premise underlying these policies is that increases in assets lead to improvement in various child outcomes over time. But little existing research examines this premise from a dynamic perspective. Using data from the NLSY79 mother and child datasets, two parallel process latent growth curve models are estimated to examine the effects of parental asset accumulation on changes in children's achievements over six years during middle childhood. Results indicate that the initial level of assets is positively associated with math scores, but not reading scores, while faster asset accumulation is associated with changes in reading scores, but not in math scores. Overall, the results suggest that the relationship between assets and various child outcomes may not be straight-forward. Different dimensions of the asset experience may lead to different outcomes, and the same dimension may also have different effects. Implications for future research and for asset-based policies are discussed.
An Institutional Embeddedness of Welfare Opinions? The Link between Public Opinion and Social Policy in the Netherlands (1970–2004)
Authors: RAVEN JUDITH , ACHTERBERG PETER , VAN DER VEEN ROMKE , YERKES MARA
Published: July 2010

A major shortcoming in the existing literature on welfare state legitimacy is that it cannot explain when social policy designs follow public preferences and when public opinion follows existing policy designs and why. Scholars examining the influence of public opinion on welfare policies, as well as scholars investigating institutional influences on individual welfare attitudes, find empirical evidence to support both relationships. While a relationship in both directions is plausible, scholars have yet to thoroughly investigate the mutual relationship between these two. Consequently, we still do not know under which circumstances welfare institutions invoke public approval of welfare policies and under which circumstances public opinion drives welfare policy. Taking a quantitative approach to public opinion and welfare state policies in the Netherlands, this paper addresses this issue in an attempt to increase our understanding of welfare state legitimacy. The results show that individual opinions influence relatively new policies, policies which are not yet fully established and where policy designs are still evolving and developing. Social policy, on the other hand, is found to influence individual opinions on established and highly institutionalised policies, but does not influence individual opinions in relatively new areas of social policy.
‘THE SOUNDS OF THE HOLLOW MOUNTAIN’: MUSICAL TRADITION AND INNOVATION IN SEVILLE CATHEDRAL IN THE EARLY RENAISSANCE
Authors: Jiménez Juan Ruiz
Published: July 2010

With the restoration of the Seville diocese in 1248, its organisation followed the model established by other Castilian cathedral chapters. Seville Cathedral's symbolic importance and the wealth created by its endowments resulted in a flourishing development of worship, in which music played a key role. The ritual space in the Mozarabic cathedral was radically transformed with the construction of the Gothic building over a period of almost a hundred years, from 1434 to 1517. In tandem with this architectural programme, the cathedral's musical resources also underwent transformation, being adapted according to changing aesthetic considerations, liturgical modifications and new spatial and acoustical demands. The city of Seville periodically welcomed the court, with the monarch and the royal household residing for extended sojourns in the Alcázar, which was renovated by Pedro I in the fourteenth century. These royal visits favoured musical exchange with the royal chapels, especially during the reign of Ferdinand and Isabel. Seville became the paradigm for the consolidation and standardisation witnessed during the fifteenth century throughout the ecclesiastical institutions of Castile and Aragon. The direct consequence of this reforming impulse was an exponential increase in the number of composers active in this environment, and the amount of polyphonic repertory created through church patronage in both the institutional and private spheres, as well as the increase in the use of that polyphony in liturgical and devotional ceremony.
Charged particle acceleration by electron Bernstein wave in a plasma channel
Authors: Kumar Asheel , Pandey Binod K. , Tripathi V.K.
Published: July 2010

A model of electron acceleration by an electron Bernstein mode in a parabolic density profile is developed. The mode has a Gaussian profile. It could be excited via the mode conversion of an electromagnetic wave or by an electron beam. As it attains a large amplitude, it axially traps electrons moving close to its parallel phase velocity, where parallel refers to the direction of static magnetic field. As the electrons are accelerated and tend to get out of phase with the wave, the transverse field of the mode enhances its energy and relativistic mass, increasing the dephasing length. The scheme can produce electron energies up to a few MeV.
Modelling and control of manipulators with flexible links working on land and underwater environments
Authors: Gümüşel Levent , Özmen Nurhan Gürsel
Published: July 2010

In this study, modelling and control of a two-link robot manipulator whose first link is rigid and the second one is flexible is considered for both land and underwater conditions. Governing equations of the systems are derived from Hamilton's Principle and differential eigenvalue problem. A computer program is developed to solve non-linear ordinary differential equations defining the system dynamics by using Runge–Kutta algorithm. The response of the system is evaluated and compared by applying classical control methods; proportional control and proportional + derivative (PD) control and an intelligent technique; integral augmented fuzzy control method. Modelling of drag torques applied to the manipulators moving horizontally under the water is presented. The study confirmed the success of the proposed integral augmented fuzzy control laws as well as classical control methods to drive flexible robots in a wide range of working envelope without overshoot compared to the classical controls.
A numerical control algorithm for navigation of an operator-driven snake-like robot with 4WD-4WS segments
Authors: Percy Andrew , Spark Ian , Ibrahim Yousef , Hardy Leon
Published: July 2010

This paper presents a new algorithm for the control of a snake-like robot with passive joints and active wheels. Each segment has four autonomously driven and steered wheels. The algorithm approximates the ideal solution in which all wheels on a segment have the same centre of curvature with wheel speeds, providing cooperative redundancy. Each hitch point joining segments traverses the same path, which is determined by an operator, prescribing the path curvature and front hitch speed. The numerical algorithm developed in this paper is simulation tested against a previously derived analytical solution for a predetermined path. Further simulations are carried out to show the effects of changing curvature and front hitch speed on hitch path, wheel angles and wheel speeds for a one, two and three segment robot.
What it means to be phonetic or phonological: the case of Romanian devoiced nasals
Authors: Tucker Benjamin V. , Warner Natasha
Published: July 2010

Abstract phonological patterns and detailed phonetic patterns can combine to produce unusual acoustic results, but criteria for what aspects of a pattern are phonetic and what aspects are phonological are often disputed. Early literature on Romanian makes mention of nasal devoicing in word-final clusters (e.g. in /basm/ ‘fairy-tale’). Using acoustic, aerodynamic and ultrasound data, the current work investigates how syllable structure, prosodic boundaries, phonetic paradigm uniformity and assimilation influence Romanian nasal devoicing. It provides instrumental phonetic documentation of devoiced nasals, a phenomenon that has not been widely studied experimentally, in a phonetically underdocumented language. We argue that sound patterns should not be separated into phonetics and phonology as two distinct systems, but neither should they all be grouped together as a single, undifferentiated system. Instead, we argue for viewing the distinction between phonetics and phonology as a largely continuous multidimensional space, within which sound patterns, including Romanian nasal devoicing, fall.
Rastafari and Cannabis: Framing a Criminal Law Exemption
Authors: Gibson Matthew
Published: July 2010

Rastafari cannabis use presents a challenge in reconciling the doctrines of freedom of religion and the criminal law. Hitherto, the domestic courts have not resolved this clash in favour of religion, displaying reluctance to explore the doctrinal limits of religious freedom. This has occurred at a time of increasing Rastafari numbers across the United Kingdom, forcing some followers to choose between adherence to either their religion or generally applicable criminal laws. Such ‘choice’ inhibits the development of domestic religious freedoms where they conflict with criminal laws protecting wider societal and communitarian interests. This dilemma could be addressed through a statutory exemption in England and Wales from domestic anti-drugs legislation for purposes of religious manifestation. This paper examines the difficult balance between the criminal law and Rastafari cannabis claims in the relevant jurisprudence. A comparative analysis highlights that treatment of religious freedom in Rastafari cannabis case law outlines not only doctrinal scope for a domestic religious drug-use exemption, but also some ways in which regulation could be practically framed. Other jurisdictions' attitudes to non-religious recreational drug use are also instructive in this task.1
Omega-3 fatty acids, cognitive impairment and Alzheimer's disease
Authors: Phillips MA
Published: July 2010

The continued imbalance of fatty acids in western diets has led to concerns about the effect this may be having on physical and mental wellbeing. Diets rich in omega-3 fatty acids, mainly docosahexaenoic acid (DHA) and eicosahexanoic acid (EPA), are argued to help with cardiovascular health as well as cognition. The mechanisms by which this happens are complex and not well understood. However, results from research in this area speculate that individuals with cognitive difficulties may benefit from increasing their omega-3 fatty acid intake, especially if they already show depleted levels of omega-3 fatty acids. This review examines mechanistic reasons behind why low intake of omega-3 fatty acids may affect physical and cognitive health, as well as evidence suggesting diets high in omega-3 fatty acids fend off cognitive disorders. It will also discuss the small body of evidence indicating that omega-3 fatty acids are depleted in those with already manifest cognitive disorders and the possibility that elevating omega-3 fatty acid status in such individuals may benefit their cognition.
Sperm head binding to epithelium of the oviduct isthmus is not an essential preliminary to mammalian fertilization - review
Authors: Hunter R. H. F.
Published: July 2010

In endeavouring to understand the nature of sperm–oviduct interactions in mammals, attention was focused on experimental models in which fertilization can occur without a preliminary phase of sperm head binding to the isthmus epithelium. The ovarian endocrine milieu imposed on the oviduct tissues plays an important role in the binding phenomenon, although less so after the time of ovulation. Nonetheless, a sperm suspension introduced into the peritoneal cavity or surgical insemination directly into the oviduct ampulla before ovulation can result in fertilization, as can a surgical model in which the isthmus has been resected and the remaining portions of the duct reanastomosed. Mating or artificial insemination after ovulation in pigs permits rapid sperm transport to the site of fertilization, and the frequency of polyspermic penetration increases with the post-ovulatory age of eggs.

Strategies underlying sperm binding were considered, especially in terms of preovulatory sperm storage and suppression of full membranous maturation. These, in turn, raised the problem of how sperm bindingin vitroto oviduct cells from prepuberal animals or to cells harvested during the luteal phase of the estrous cycle, or to cells from the ampulla or even the tracheal epithelium, can act to regulate sperm storage and maturation with precision. In an evolutionary perspective, preovulatory binding of diverse populations of cells to the endosalpinx may have developed as a form of fine tuning to assist in sperm selection, to synchronize completion of capacitation with the events of ovulation, and to promote monospermic fertilization by a controlled release of competent gametes.
The effect of age on language attrition: Evidence from bilingual returnees
Authors: FLORES CRISTINA
Published: July 2010

The present study investigates the syntactic competence of bilingual Portuguese–German returnees who have lost regular contact with their L2 (German). The main criterion which distinguishes the participants is the age of input loss. This allows their division into two main groups: speakers who lost German input during early childhood (between ages seven and ten) and speakers who were eleven or older when they moved away from the German environment. Focusing on verb placement in main and embedded clauses, the available data show strong evidence of the existence of a stabilization phase following the acquisition period. The speakers who lost L2 input earlier than age eleven show significantly more syntactic deficits than the other speakers. However, the observed attrition effects seem to be the result of insufficient L2 activation, rather than the expression of undergoing competence loss.
Bilingual advantage in attentional control: Evidence from the forced-attention dichotic listening paradigm
Authors: SOVERI ANNA , LAINE MATTI , HÄMÄLÄINEN HEIKKI , HUGDAHL KENNETH
Published: July 2010

It has been claimed that due to their experience in controlling two languages, bilinguals exceed monolinguals in certain executive functions, especially inhibition of task-irrelevant stimuli. Here we investigated the effects of bilingualism on an executive phonological task, namely the forced-attention dichotic listening task with syllabic stimuli. In the standard non-forced (NF) condition, the participants reported all syllables they heard, be it from the right or the left ear. In the forced-right (FR) and forced-left (FL) attention conditions, they had to direct their attention to either the right- or the left-ear stimulus and inhibit information coming to the other ear. We tested Finnish monolinguals and early simultaneous Finnish–Swedish bilinguals from two age groups: (30–50-year-olds and 60–74-year-olds). The results showed that the bilinguals performed better than the monolinguals in the FR and FL conditions. This supports the idea of a bilingual advantage in directing attention and inhibiting task-irrelevant stimuli.
Importance of heat transport and local air‐sea heat fluxes for Barents Sea climate variability
Authors: Sandø A. B. , Nilsen J. E. Ø. , Gao Y. , Lohmann K.
Published: July 2010

An isopycnic coordinate ocean model has been used to investigate the importance of different mechanisms on the Barents Sea climate variability for the period 1948–2006 Observed and simulated time series from the Kola Section are used to evaluate the model, and the model captures both the temperature and its variability. Based on lagged correlations between different climatological time series, it is shown here that heat transport through the Barents Sea Opening and solar heat flux are about equally important to the climate variability in the Barents Sea. The heat transport has greater potential of predictability due to a relatively long time lag. Furthermore, the non‐solar and the net heat flux variability is governed by fluctuations in the oceanic heat content. All time series considered important for the Barents Sea climate variability show significant correlation to the North Atlantic Oscillation (NAO) pattern on a decadal time scale. As the associated low pressure system in the Nordic Seas moves eastward from 1948–1977 to 1978–2006, the correlation between NAO and heat transports into the Barents Sea becomes higher.
Changes in extreme precipitation in Texas
Authors: Mishra Ashok K. , Singh Vijay P.
Published: July 2010

An increase in global temperature leads to the intensification of a hydrologic cycle, which, in turn, affects spatiotemporal characteristics of precipitation. The distribution of precipitation plays an important role in water resources planning at regional and local scales. In this study, the state of Texas was used as a study area. Five kinds of annual precipitation extremes, based on the annual maximum (1, 7, and 30 days) and on the threshold level (95th and 97.5 percentiles), were analyzed. Applying the extreme value theory, a generalized extreme value distribution was fitted to these extremes, and quantiles were calculated for the preclimatic change period (1925–1964) and the postclimatic change period (1965–2005) to understand the possible changes in frequency patterns in terms of both spatial and temporal scales. Furthermore, the trend analysis of extreme precipitation was performed using the Mann‐Kendall test for preclimatic and postclimatic change periods to determine possible increasing or decreasing patterns. On the basis of the quantiles obtained for different return periods using 1 day extreme precipitation on an annual scale, mixed results were observed. The stations with higher quantiles, based on 1 day extreme events during the preclimatic period, were located mostly in the subtropical subhumid regions, whereas those during the postclimatic change period were located in most of the climatic zones. Similarly, results based on other extreme variables showed that the changes in the temporal and spatial characteristics of quantiles as well as increasing or decreasing patterns were observed at different locations during preclimatic and postclimatic change periods.
Volcanic aerosol layers observed with multiwavelength Raman lidar over central Europe in 2008–2009
Authors: Mattis Ina , Siefert Patric , Müller Detlef , Tesche Matthias , Hiebsch Anja , Kanitz Thomas , Schmidt Jörg , Finger Fanny , Wandinger Ulla , Ansmann Albert
Published: July 2010

In the framework of regular European Aerosol Research Lidar Network (EARLINET) observations, aerosol layers have been monitored with a multiwavelength aerosol Raman lidar in the upper troposphere and lower stratosphere over Leipzig (51.4°N, 12.4°E), Germany, since the summer of 2008. The origins of these layers are eruptions of different volcanoes on the Aleutian Islands, Kamchatka, Alaska, and on the Kuril Islands. FLEXPART transport simulations show that the volcanic aerosol is advected from Alaska to central Europe within about 7 days. The aerosol layers typically occurred in the upper troposphere above 5 km height and in the lower stratosphere below 25 km height. The optical depths of the volcanic aerosol layers are mostly between 0.004 and 0.025 at 532 nm. The wavelength dependence of the backscatter coefficients and extinction coefficients indicate Ångström exponents from 1.0–2.0. Lidar ratios in the stratosphere are found in the range from 30–60 sr (355 nm) and 30–45 sr (532 nm). The estimation of the effective radius, surface‐area, and mass concentrations of a volcanic aerosol layer, observed well within the stratosphere at end of August 2009, reveals values of 0.1–0.2 μm, 5–10 μm2 cm−3, and 0.3–0.5 μg m−3, respectively.
Physical mechanisms of the seasonal, subseasonal, and high‐frequency variability in the seasonal cycle of summer precipitation in Korea
Authors: Kim Kwang‐Yul , Roh Joon‐Woo , Lee Dong‐Kyou , Jhun Jong‐Ghap
Published: July 2010

Three distinct physical mechanisms in the seasonal cycle of the 120 day (19 May to 15 September) summer precipitation in Korea (126°E–130°E, 33°N–38°N) were identified using the 1979–2008 observed precipitation records at 61 Korea Meteorological Administration stations. Detailed space‐time structures of the physical mechanisms of precipitation variability were derived using the daily National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis data over Asia (80°E–180°E, 0°–60°N). The seasonal cycle of summertime precipitation in Korea exhibits three principal temporal scales (seasonal, subseasonal, and high‐frequency components) of variability, each with distinct physical mechanisms. The seasonal component represents the variability associated with the evolution of the Asian summer monsoon, specifically the East Asia summer monsoon, governed primarily by large‐scale circulation as a result of changes in sea level pressure contrasts between the Asian continent and the surrounding oceans. The arrival and the duration of a monsoon front primarily shape the seasonal evolution of precipitation in Korea. The bimodal peaks are due to the low‐level circulation change as a result of redistribution of temperature and, subsequently, of sea level pressure during summer. The subseasonal component has characteristic time scales of 10–30 days and is associated with eastward‐moving upper‐level disturbances at ∼40°N. The upper‐level disturbances affect the meridional circulations, resulting in low‐level convergence/divergence not only underneath but also to the south and to the north of the disturbance. From mid‐July to mid‐August, the subseasonal component is more clearly observable, and the period of oscillations is generally shorter, than during early or late summer. The high‐frequency component with time scales of less than 10 days is associated with midlatitude baroclinic Rossby waves; synoptic‐scale variations of upper‐level geopotential height and low‐level moisture convergence are well correlated with the high‐frequency variability of precipitation in Korea. Positive precipitation anomalies over Korea correspond to an upper‐level divergence with anticyclonic wind anomalies caused by baroclinic Rossby waves with axes around ∼40°N. The vertical structures of key physical variables are well explained in the context of baroclinic instability with the geopotential height anomaly field connecting the upper‐level divergence and the lower‐level convergence tilted westward with height and the temperature anomaly field slanting slightly in the opposite direction.
Tundra carbon balance under varying temperature and moisture regimes
Authors: Huemmrich K. F. , Kinoshita G. , Gamon J. A. , Houston S. , Kwon H. , Oechel W. C.
Published: July 2010

To understand the effects of environmental change on tundra carbon balance, a manipulation experiment was performed in wet sedge tundra near Barrow, Alaska. Three replicates of six environmental treatments were made: control, heating, raising or lowering water table, and heating along with raising or lowering water table. Carbon fluxes were measured using a portable chamber for six days during the 2001 growing season. Spectral reflectance and meteorological measurements were also collected. Empirical models derived from flux measurements were developed for daily gross ecosystem production (GEP) and ecosystem respiration (Re). The amount of photosynthetically active radiation absorbed by the plants was strongly correlated with GEP. This relationship was not affected by treatment or time during the growing season. Re was related to soil temperature with a different relationship for each water level treatment. Re in the lowered water table treatment had a strong response to temperature changes, while the raised water table treatment showed little temperature response. These models calculated daily net ecosystem exchange for all of the treatments over the growing season. Warming increased both the seasonal carbon gain and carbon loss. By the end of summer the lowered water table treatments, both heated and unheated, were net carbon sources while all other treatments were sinks. Warming and/or raising the water table increased the strength of the net sink. Over the timescale of this experiment, water table primarily determined whether the ecosystem was a source or sink, with temperature modifying the strength of the source or sink.
Real‐time reservoir flood operation during typhoon attacks
Authors: Huang Wen‐Cheng , Hsieh Chi‐Liang
Published: July 2010

This paper introduces an early warning model for floods for real‐time reservoir operation during typhoons. The model contains three main parts: (a) “flood watch” to monitor the current flood situation, (b) “flood release” to estimate probable reservoir releases in the near future, and (c) “decision analysis” to determine an appropriate release policy. A new flood alert index is defined to account for risk and is used to augment reservoir flood operation. In this study, a genetic algorithm‐based rule is presented to specify suitable releases in response to the nature of flood inflows and reservoir water level. To demonstrate the procedure, the proposed method was successfully used in a real reservoir in northern Taiwan. The implementation of such a model proves that it can assist reservoir operators in taking timely action during typhoon events.
Arctic Landscapes in Transition: Responses to Thawing Permafrost
Authors: Rowland J. C. , Jones C. E. , Altmann G. , Bryan R. , Crosby B. T. , Hinzman L. D. , Kane D. L. , Lawrence D. M. , Mancino A. , Marsh P. , McNamara J. P. , Romanvosky V. E. , Toniolo H. , Travis B. J. , Trochim E. , Wilson C. J. , Geernaert G. L.
Published: July 2010

Observations indicate that over the past several decades, geomorphic processes in the Arctic have been changing or intensifying. Coastal erosion, which currently supplies most of the sediment and carbon to the Arctic Ocean [Rachold et al., 2000], may have doubled since 1955 [Mars and Houseknecht, 2007]. Further inland, expansion of channel networks [Toniolo et al., 2009] and increased river bank erosion [Costard et al., 2007] have been attributed to warming. Lakes, ponds, and wetlands appear to be more dynamic, growing in some areas, shrinking in others, and changing distribution across lowland regions [e.g., Smith et al., 2005]. On the Arctic coastal plain, recent degradation of frozen ground previously stable for thousands of years suggests 10–30% of lowland and tundra landscapes may be affected by even modest warming [Jorgenson et al., 2006]. In headwater regions, hillslope soil erosion and landslides are increasing [e.g., Gooseff et al., 2009].
Study of streamers in gradient density air: Table top modeling of red sprites
Authors: Opaits Dmitry F. , Shneider Mikhail N. , Howard Philip J. , Miles Richard B. , Milikh Gennady M.
Published: July 2010

Red sprites are large scale weakly ionized non‐equilibrium electrical discharges that occur high above thunderstorm clouds, spanning the altitude range 50 kilometers to 90 kilometers above the Earth's surface. Their streamer‐like nature has been pointed out by a number of groups. Streamer models used for the description of sprites are usually verified experimentally. However, sprites develop in a highly non‐uniform air, where density changes by a factor of ∼2.7 every 7.2 km, whereas streamer studies have been performed at different but uniform densities. In this paper we present the results of the first attempt to simulate sprites in laboratory by using streamer discharges in a gradient density air (the results of this paper were presented in 2009 Fall AGU meeting). The purpose of the experiments is to obtain data that could be used for validation of numerical and analytical models (the first results of a numerical study of red sprites (streamers) in a gradient density atmosphere were recently published by Luque and Ebert (2010)).
Hemispheric asymmetry of the magnetic field wrapping pattern in the Venusian magnetotail
Authors: Zhang T. L. , Baumjohann W. , Du J. , Nakamura R. , Jarvinen R. , Kallio E. , Du A. M. , Balikhin M. , Luhmann J. G. , Russell C. T.
Published: July 2010

We examine statistically the magnetic field in the Venusian magnetotail which is formed by the draping of interplanetary magnetic field lines. Although the near‐planet and distant magnetotail regions have been sampled by the various missions to Venus and the general magnetic features of the distant magnetotail are well established, the near wake region from about 1.3 to 3 Venusian radii downstream of the planet remained unexplored until the Venus Express mission. Here we report the unanticipated finding of a draped field reversal in one hemisphere of the near Venus tail. When ordered by the interplanetary electric field orientation, the magnetic field lines in the hemisphere with inward motional electric field apparently are wrapped more tightly around Venus than in the other hemisphere, thus forming a field reversal region in the this portion of the near tail. A global hybrid simulation produces what we see and provides a three‐dimensional view of the observed hemispherical asymmetry.