bluuebunny/crossref_metadata_2025 huggingface dataset:
New perspectives on the physics of birdsong
Authors: Trevisan M. A. , Mindlin G. B.
Published: July 2009

In this work, we revisit the path that has been travelled during the last few years towards the modelling of the avian vocal organ, the
syrinx
, using numerical and theoretical techniques from bifurcation theory as analysing tools and present experimental support for the models. This fruitful perspective allowed the retracing of many acoustic features of syllables to intrinsic properties of the syrinx, thereby relocating the bird phonatory organ from the role of a mere vocal instrument of the nervous system to a central source of complex acoustical behaviour.
Species competition: coexistence, exclusion and clustering
Authors: Hernández-García Emilio , López Cristóbal , Pigolotti Simone , Andersen Ken H.
Published: July 2009

We present properties of Lotka–Volterra equations describing ecological competition among a large number of interacting species. First we extend previous stability conditions to the case of a non-homogeneous niche space, i.e. that of a carrying capacity depending on the species trait. Second, we discuss mechanisms leading to species clustering and obtain an analytical solution for a state with a lumped species distribution for a specific instance of the system. We also discuss how realistic ecological interactions may result in different types of competition coefficients.
Associative sequence learning: the role of experience in the development of imitation and the mirror system
Authors: Catmur Caroline , Walsh Vincent , Heyes Cecilia
Published: July 2009

A core requirement for imitation is a capacity to solve the
correspondence problem
; to map observed onto executed actions, even when observation and execution yield sensory inputs in different modalities and coordinate frames. Until recently, it was assumed that the human capacity to solve the correspondence problem is innate. However, it is now becoming apparent that, as predicted by the associative sequence learning model, experience, and especially sensorimotor experience, plays a critical role in the development of imitation. We review evidence from studies of non-human animals, children and adults, focusing on research in cognitive neuroscience that uses training and naturally occurring variations in expertise to examine the role of experience in the formation of the mirror system. The relevance of this research depends on the widely held assumption that the mirror system plays a causal role in generating imitative behaviour. We also report original data supporting this assumption. These data show that theta-burst transcranial magnetic stimulation of the inferior frontal gyrus, a classical mirror system area, disrupts automatic imitation of finger movements. We discuss the implications of the evidence reviewed for the evolution, development and intentional control of imitation.
Ratcheting up the ratchet: on the evolution of cumulative culture
Authors: Tennie Claudio , Call Josep , Tomasello Michael
Published: July 2009

Some researchers have claimed that chimpanzee and human culture rest on homologous cognitive and learning mechanisms. While clearly there are some homologous mechanisms, we argue here that there are some different mechanisms at work as well. Chimpanzee cultural traditions represent behavioural biases of different populations, all within the species’ existing cognitive repertoire (what we call the ‘zone of latent solutions’) that are generated by founder effects, individual learning and mostly product-oriented (rather than process-oriented) copying. Human culture, in contrast, has the distinctive characteristic that it accumulates modifications over time (what we call the ‘ratchet effect’). This difference results from the facts that (i) human social learning is more oriented towards process than product and (ii) unique forms of human cooperation lead to active teaching, social motivations for conformity and normative sanctions against non-conformity. Together, these unique processes of social learning and cooperation lead to humans’ unique form of cumulative cultural evolution.
Movements, actions and tool-use actions: an ideomotor approach to imitation
Authors: Massen Cristina , Prinz Wolfgang
Published: July 2009

In this article we discuss both merits and limitations of the ideomotor approach to action control and action imitation. In the first part, we give a brief outline of ideomotor theory and its functional implications for imitation and related kinds of behaviours. In the subsequent sections, we summarize pertinent experimental studies on action imitation and action induction. These studies show that action perception modulates action planning in a number of ways, of which imitation is but one. In the last part, we move from regular actions to tool-use actions, raising the issue of whether and how watching others' tool-use actions leads to corresponding behaviours in observers. Here, we discuss experiments aimed at dissociating the relative roles of environmental targets, bodily movements and target-to-movement-mappings (action rules) in the observation of tool-use actions. Our findings indicate a strong role for action rules in the observation and imitation of tool-use actions. We argue that, in order to account for these findings, ideomotor theory needs to be extended to take mappings between bodily movements and environmental effects into account.
Inhibition of imitative behaviour and social cognition
Authors: Brass Marcel , Ruby Perrine , Spengler Stephanie
Published: July 2009

There is converging evidence that the observation of an action activates a corresponding motor representation in the observer through a ‘mirror-matching’ mechanism. However, research on such ‘shared representations’ of perception and action has widely neglected the question of how we can distinguish our own motor intentions from externally triggered motor representations. By investigating the inhibition of imitative response tendencies, as an index for the control of shared representations, we can show that self–other distinction plays a fundamental role in the control of shared representations. Furthermore, we demonstrate that overlapping brain activations can be found in the anterior fronto-median cortex (aFMC) and the temporo-parietal junction (TPJ) area for the control of shared representations and complex social-cognitive tasks, such as mental state attribution. In a functional magnetic resonance imaging experiment, we functionally dissociate the roles of TPJ and aFMC during the control of shared representations. Finally, we propose a hypothesis stating that the control of shared representations might be the missing link between functions of the mirror system and mental state attribution.
Prenatal and Postnatal Management of Hydronephrosis
Authors: Rao Pravin K. , Palmer Jeffrey S.
Published: July 2009

The majority of pregnant women in the U.S. undergo prenatal ultrasonography and approximately 0.5% of these examinations will detect fetal malformations. Up to one-half of these abnormalities include the genitourinary system and the most common urological finding is hydronephrosis. Some conditions associated with prenatal hydronephrosis portend a poor prognosis, while others can follow a fairly benign course. This review focuses on the definition and prenatal assessment of hydronephrosis, fetal intervention, and postnatal management.
Microliths in the parotid of ferret investigated by electron microscopy and microanalysis
Authors: Triantafyllou Asterios , Harrison John D. , Garrett John R.
Published: July 2009

The present investigation is an attempt to determine the occurrence, elemental composition and formation of microliths in the parotid of ferret. Parotids from four normal ferrets were examined by electron microscopy and X‐ray microanalysis. Crystalline microliths were found in phagosomes of acinar cells, which occasionally contained secretory material, and in phagosomes situated between mitochondria of striated ductal cells. Crystalline microliths and microliths that consisted of granular material either without crystals or mixed with a component of crystals were found in lumina, where they were often associated with cellular debris. The crystals contained calcium and phosphorus. Phagy and stagnation related to pockets of inefficient secretory activity have been previously found to be features of the parotid of ferret. Thus, possibly persistent degradation of redundant cellular material, particularly secretory granules, in phagosomes results in accumulation of calcium and leads to calcified microliths, whereas consolidation of stagnant debris extracellularly does not involve such accumulation and leads to non‐calcified or mixed microliths.
Tumourigenic effect of Schistosoma haematobium total antigen in mammalian cells
Authors: Botelho Monica , Oliveira Paula , Gomes Joana , Gartner Fatima , Lopes Carlos , Correia da Costa Jose Manuel , Machado Jose Carlos
Published: July 2009

Schistosoma haematobium is endemic in several regions of Africa and has been shown to be associated with predominantly squamous cell bladder carcinoma. The mechanisms underlying the association between S. haematobium and bladder squamous cell carcinoma is largely unknown. All the reports so far, demonstrate exclusively an epidemiological evidence linking S. haematobium infection with squamous cell bladder carcinoma. We hypothesized that these parasite antigens might induce tumourigenesis. For this, we used normal mammalian cells of Chinese hamster ovary (CHO) and treated the cells in culture with S. haematobium total antigen (Sh). Our results showed increased proliferation in Sh‐treated cells in comparison with the controls. The CHO cells exposed to Sh were inoculated subcutaneously into male nude mice and formed sarcomas (n = 5/5). The cells from the sarcomas expressed vimentin filaments and were negative to cytokeratin. Our results demonstrate for the first time that S. haematobium antigens induce tumour development in nude mice.
Diabetes induces stromal remodelling and increase in chondroitin sulphate proteoglycans of the rat ventral prostate
Authors: Ribeiro Daniele Lisboa , Taboga Sebastião Roberto , Góes Rejane Maira
Published: July 2009

Extracellular matrix (ECM) remodelling is an important process involved in prostate cancer progression. Alterations in ECM caused by diabetes in different tissues such as kidney is well described; however, it is poorly investigated in prostate. The aim of this study was to evaluate changes in ECM of rat prostate showing gland atrophy caused by diabetes and their implications in development of malignant lesions. Diabetes was induced in Wistar rats using alloxan (45 mg/kg bw). After 90 days of diabetes onset, animals were killed and ventral prostate was removed and prepared for light microscopy following immunoreaction for fibronectin, chondroitin sulphate and Picrossirius staining for collagen fibres. Proteoglycans (PG) were identified at transmission electron microscopy after fixation with Cuprolinic Blue. Diabetes led to a thickening of 25% in the acinar basement membrane accompanied by increase and disorganization of its proteoglycans (P1). Three additional populations of prostatic stromal PGs were identified: collagen fibril linked (P2) and interstitial (P3) and (P4) PGs. Diabetes increased P3 and mainly P4 which had higher dimension and accumulated around the smooth muscle cells. In addition, an increase in chondrotin sulphate (33%, mainly in sites where P4 were noted) and collagen (44%) was noted in diabetic rats, whereas fibronectin did not change. Atrophic changes observed in rat ventral prostate after diabetes are accompanied by stromal remodelation related to increase in collagen and chondroitin sulphate proteoglycans. Thus, diabetes can promote a stromal microenvironment rich in elements that could favour cell migration, proliferation and pathological process.
Chronic treatment with sildenafil stimulates Leydig cell and testosterone secretion
Authors: Saraiva Karina Lidianne Alcântara , Silva Amanda Karolina Soares E. , Wanderley Maria Inês , De Araújo Araken Almeida , De Souza José Roberto Botelho , Peixoto Christina Alves
Published: July 2009

The phosphodiesterase type 5 (PDE5) inhibitor, Sildenafil, is a novel, oral treatment approach for pulmonary hypertension. As Leydig cells present PDE5, this study was conducted to investigate the effects of the chronic treatment with Sildenafil (25 mg/kg) on male Swiss Webster mice steroidogenesis. After a 4‐week long experimental design, Leydig cells were analysed by morphological and immunocytochemical procedures. Serum testosterone was assayed by radioimmunoassay. Leydig cells presented noteworthy ultrastructural alterations, such as a vesicular smooth endoplasmic reticulum, large vacuoles scattered through the cytoplasm, enlarged mitochondria with discontinue cristaes and whorle membranes with vesicles at the periphery, which are typical characteristics of an activated steroid‐secreting cell. Important immunocytochemical labelling for steroidogenic acute regulatory protein, cytochrome P450 side‐chain cleavage enzyme and testosterone were detected in isolated Leydig cells. In addition, Sildenafil‐treated mice showed significant increased levels of total testosterone. The results obtained in the present study are consistent with the hypothesis that the accumulation of cyclic guanosine monophosphate by PDE5 inhibition could be involved in the androgen biosynthesis stimulation. Important clinical implications of hormonal disorders should be taken into account for patients with pulmonary hypertension.
Optimising the free radical scavenging activity of shrimp protein hydrolysate produced with alcalase using response surface methodology
Authors: Cao Wenhong , Zhang Chaohua , Hong Pengzhi , Ji Hongwu
Published: July 2009

Response surface methodology (RSM) was used to optimise the hydrolysis parameters of Acetes chinensis by Alcalase 2.4L in order to obtain a hydrolysate with potent radical scavenging activity. The parameters were temperature, pH and enzyme concentration/substrate concentration (E/S) ratio with degree of hydrolysis (DH) being the response. The results showed that the optimum condition was: temperature at 57 °C, pH at 8.0, E/S ratio at 2.6AU 100 g−1 shrimp, hydrolysis time 3 h. The DH was 26.32%, the hydroxyl radical scavenging activity was up to 88.12% and the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity was 35.61%. The gel column filtration chromatography by a Sephadex G‐25 column yielded five fractions. The molecular weight of the most potent free radical scavenging activity fraction ranged from 915 to 207 Da, its IC50 for hydroxyl radical was 0.03 mg mL−1, and IC50 for DPPH radical was 8.86 mg mL−1.
Freezing of tilapia fillets in an air blast freezer
Authors: Tan Fock‐Lai , Fok Sai‐Cheong
Published: July 2009

This paper explores the numerical simulation of freezing tilapia fillets of five different geometries, which are the slab, elliptical, disc, spherical and cylindrical shapes, in an air blast freezer. The air velocities and temperatures inside the freezer are varied in the simulation to determine the freezing times and energy consumptions for freezing the tilapia fillets of different shapes. The results show that the cylindrical‐shaped fillet has the longest freezing time and also required the most energy for freezing. The slab‐shaped fillet has the shortest freezing time, but the spherical‐shaped fillet requires the least energy to freeze. The simulation is also applied to a case study to compare the processing rate, energy consumption and the cost of freezing the fillets of different shapes. The freezing cost for a tray of spherical‐shaped fillet is the lowest among all.
Quality preservation in chilled and frozen fish products by employment of slurry ice and natural antioxidants
Authors: Medina Isabel , Gallardo José M. , Aubourg Santiago P.
Published: July 2009

Fish products are known to provide high levels of constituents important for the human diet. At the same time, wild and farmed fish species are highly perishable products, the quality and freshness of which rapidly declines post‐mortem. Accordingly, efficient storage and processing technologies need to be employed to reduce postmortem quality losses until the product reaches the consumer. The present review covers recent efforts carried out on some new and advanced strategies related to chilled and frozen storage. In the first part, research concerning the use of binary systems (slurry ice) is reviewed, this focussed on the commercialisation of fresh fish products as such or to its employment as raw material for processing. Then, the application of exogenous antioxidants to ensure retention of high quality is addressed; in this part, special attention is accorded to the endogenous antioxidant content retention and to the antioxidant/pro‐oxidant balance in fish foods.
Creating supportive clinical learning environments: an intervention study
Authors: Henderson Amanda , Twentyman Michelle , Eaton Emma , Creedy Debra , Stapleton Peta , Lloyd Belinda
Published: July 2009

Aim.  To assess the impact of an intervention aimed to build capacity of registered nurses to enhance the clinical learning environment for undergraduate nursing students. Workplace learning is vital for the development of skills, attributes and knowledge of student nurses. Registered nurses need to be appropriately prepared to maximise student learning during clinical placement.

Background.  The quality of student learning during clinical practicum is largely dependent on interactions with ward staff.

Design.  A quasi‐experimental design.

Method.  Measurement of students’ perceptions of the psycho social learning environment during and outside of the intervention period was used to evaluate the capacity building intervention. The capacity building intervention consisted of interactive education in clinical areas over a six‐week period for registered nurses in two acute surgical wards.

Results.  First, second and third year students (n = 62) who undertook their clinical practicum in the two surgical wards, before, during and six months after the capacity building intervention assessed the psycho‐social learning environment at the time of their clinical practicum. Findings showed that students who undertook their clinical practicum during the intervention period rated the psycho‐social clinical learning environment significantly higher than students who undertook their practicum at times outside of the intervention period.

Conclusions.  An experienced researcher/educator conducting capacity building sessions can effectively assist and support registered nurses to engage with students.

Relevance to clinical practice.  Capacity building sessions can improve practice, however, structures and processes that ensure continuation of practice change need to be embedded for improvements to be sustained.
Child health nurses’ roles and attitudes in reducing children’s tobacco smoke exposure
Authors: Carlsson Noomi , Johansson AnnaKarin , Hermansson Göran , Andersson‐Gäre Boel
Published: July 2009

Aim.  To investigate and analyse the attitudes to tobacco prevention among child healthcare nurses, to study how tobacco preventive work is carried out at child healthcare centres today. To evaluate how the tobacco preventive work had changed in child health care since the Swedish National Board of Health and Welfare’s national evaluation in 1997.

Background.  Exposure to environmental tobacco smoke has adverse health effects. Interventions aiming at minimising environmental tobacco smoke have been developed and implemented at child healthcare centres in Sweden but the long‐term effects of the interventions have not been studied.

Design.  Survey.

Methods.  In 2004, a postal questionnaire was sent to all nurses (n = 196) working at 92 child healthcare centres in two counties in south‐eastern Sweden. The questionnaire was based on questions used by the National Board of Health and Welfare in their national evaluation in 1997 and individual semi‐structured interviews performed for this study.

Results.  Almost all the nurses considered it very important to ask parents about their smoking habits (median 9·5, range 5·1–10·0). Collaboration with antenatal care had decreased since 1997. Nearly all the nurses mentioned difficulties in reaching fathers (70%), groups such as immigrant families (87%) and socially vulnerable families (94%) with the tobacco preventive programme. No nurses reported having special strategies to reach these groups.

Conclusions.  Improvement of methods for tobacco prevention at child healthcare centres is called for, especially for vulnerable groups in society. However, the positive attitude among nurses found in this study forms a promising basis for successful interventions.

Relevance to clinical practice.  This study shows that launching national programmes for tobacco prevention is not sufficient to achieve sustainable work. Nurses working in child healthcare centres have an overall positive attitude to tobacco prevention but need continuous education and training in communication skills especially to reach social vulnerable groups. Regular feedback from systematic follow‐ups might increase motivation for this work.
Rice endosperm iron biofortification by targeted and synergistic action of nicotianamine synthase and ferritin
Authors: Wirth Judith , Poletti Susanna , Aeschlimann Beat , Yakandawala Nandadeva , Drosse Benedikt , Osorio Sonia , Tohge Takayuki , Fernie Alisdair R. , Günther Detlef , Gruissem Wilhelm , Sautter Christof
Published: July 2009

Nearly one‐third of the world's population, mostly women and children, suffer from iron malnutrition and its consequences, such as anaemia or impaired mental development. Iron fortification of food is difficult because soluble iron is either unstable or unpalatable, and non‐soluble iron is not bioavailable. Genetic engineering of crop plants to increase iron content has therefore emerged as an alternative for iron biofortification. To date, strategies to increase iron content have relied on single genes, with limited success. Our work focuses on rice as a model plant, because it feeds one‐half of the world's population, including the majority of the iron‐malnourished population. Using the targeted expression of two transgenes, nicotianamine synthase and ferritin, we increased the iron content of rice endosperm by more than six‐fold. Analysis of transgenic rice lines confirmed that, in combination, they provide a synergistic effect on iron uptake and storage. Laser ablation‐inductively coupled plasma‐mass spectrometry showed that the iron in the endosperm of the transgenic rice lines accumulated in spots, most probably as a consequence of spatially restricted ferritin accumulation. Agronomic evaluation of the high‐iron rice lines did not reveal a yield penalty or significant changes in trait characters, except for a tendency to earlier flowering. Overall, we have demonstrated that rice can be engineered with a small number of genes to achieve iron biofortification at a dietary significant level.
ON THE SUPPOSED MORAL HARM OF SELECTING FOR DEAFNESS
Authors: FAHMY MELISSA SEYMOUR
Published: July 2009

This paper demonstrates that accounting for the moral harm of selecting for deafness is not as simple or obvious as the widespread negative response from the hearing community would suggest. The central questions addressed by the paper are whether our moral disquiet with regard to selecting for deafness can be adequately defended, and if so, what this might entail. The paper considers several different strategies for accounting for the supposed moral harm of selecting for deafness and concludes that the deaf case cannot be treated in isolation. Accounting for the moral harm of selecting for deafness necessarily entails moral implications for other cases of procreation and procreative decision‐making, including unassisted coital reproduction. The lesson to be learned from the deaf case is that we need norms that govern not just the use of reproductive technology, but procreation and procreative decision‐making in all of its various forms.
Evolution of Capital Structure in East Asia—Corporate Inertia or Endeavours?
Authors: Driffield Nigel , Pal Sarmistha
Published: July 2009

The paper examines the capital structure adjustment dynamics of listed non-financial corporations in seven east Asian countries before, during and after the crisis of 1997–1998. Our methodology allows for speeds of adjustment to vary, not only among firms, but also over time, distinguishing between cases of sudden and smooth adjustment. Whereas, compared with firms in the least affected countries, average leverages were much higher, generalized method-of-moments analysis of the Worldscope panel data suggests that average speeds of adjustment were lower in the worst affected countries. This holds also for the severely financially distressed firms in some worst affected countries, though the trend reversed in the post-crisis period. These findings have important implications for the regulatory environment as well as access to market finance.
CHEMICAL AND FUNCTIONAL PROPERTIES OF VARIOUS BLENDS OF PHOSPHATES
Authors: KIM JIN‐SOO , SCHNEE RAINER , PARK JAE W.
Published: July 2009

Chemical and functional properties of various blends of phosphate were examined and compared with the conventional phosphate (M‐CP: a mechanical blend [50:50] of sodium tripolyphosphate [STPP] and tetrasodium pyrophosphate [TSPP]). Regardless of solution temperature and brine concentration, the solubilities of various blends of phosphates, especially M‐1 (a mechanical blend [50:50] of tetrapotassium pyrophosphate and STPP), M‐LC (a long‐chained sodium hexametapolyphosphate [SHMP] treated with trisodium phosphate [TSP]) and M‐MC (a middle‐chained SHMP treated with TSP), except for C‐S (a chemical blend [50:50] of STPP and TSPP for faster/higher solubility) and C‐V (a chemical blend [50:50] of STPP and TSPP for higher viscosity), were higher than that of M‐CP. The scanning electronic microscopic image revealed that the structures of various blends of phosphate were quite different. Comparing with M‐CP, C‐V was superior in viscosity, water retention ability (WRA), emulsifying activity and cooking stability. M‐1 was superior in WRA compared to M‐CP.

PRACTICAL APPLICATIONS

Conventional blending for phosphates is typically made through simple mechanical mixing. In our study, we featured chemically blended phosphates and found that some of them demonstrated superior functional properties. With this advantage, the use of chemically blended phosphate could reduce the usage level while achieving a similar or better performance.
SURFACE ACOUSTIC WAVE PROPAGATION IN GaN-ON-SAPPHIRE UNDER PULSED SUB-BAND ULTRAVIOLET ILLUMINATION
Authors: CHIVUKULA VENKATA S. , CIPLYS DAUMANTAS , LIU KAI , SHUR MICHAEL S. , GASKA REMIS
Published: July 2009

We investigated transient amplitude and phase response of GaN -on-sapphire SAW delay-line device subjected to pulsed sub-band UV illumination. We correlated these results with photoluminescence measurements in two GaN samples with the same emission spectra but different carrier lifetime. The SAW response measurements showed that under pulse illumination the sample with shorter lifetime exhibited gradual rise in the phase and amplitude change in millisecond range. Under similar conditions, the sample with a longer lifetime responded faster. We attribute this change to the presence of defect related transitions of the photoexcited carriers and their interaction with surface acoustic waves. Our results demonstrate the possibility of characterization of compensated GaN samples by measuring the phase and amplitude variations in the SAW transmission mode under pulsed UV excitation.
MONTE CARLO SIMULATIONS OF In0.75Ga0.25As MOSFETs AT 0.5 V SUPPLY VOLTAGE FOR HIGH-PERFORMANCE CMOS
Authors: AYUBI-MOAK J. S. , KALNA K. , ASENOV A.
Published: July 2009

The performance of implant-free (IF), n-type III-V MOSFETs with an In 0.75 Ga 0.25 As channel have been evaluated using a 2D finite-element Monte Carlo device simulator. We investigate the device performance of a set of scaled transistors with gate lengths of 30, 20 and 15 nm at a drain bias of 0.5 V to determine whether this novel architecture can deliver the high drain current at low bias conditions required for high-performance CMOS applications.
InAlN/GaN MOS-HEMT WITH THERMALLY GROWN OXIDE
Authors: ALOMARI M. , MEDJDOUB F. , KOHN E. , DI FORTE-POISSON M-A. , DELAGE S. , CARLIN J.-F. , GRANDJEAN N. , GAQUIÈRE C.
Published: July 2009

We report on the investigation of lattice matched InAlN / GaN MOS-HEMT structures prepared by thermal oxidation at 800 °C in oxygen atmosphere for two minutes. The gate leakage current was reduced by two orders of magnitude. Pulse measurements showed lag effects similar to what is observed for devices without oxidation, indicating a high quality native oxide. The MOS-HEMT showed no degradation in the small signal characteristics and yielded a power density of 5 W/mm at 30 V drain voltage at 10 GHz, power added efficiency of 42% and Ft and Fmax of 42 and 61 GHz respectively, illustrating the capability of such MOS-HEMT to operate at high frequencies.
CROSSOVER FIELDS IN GRAIN-BOUNDARY FLUX PINNING IN MAGNESIUM DIBORIDE FILMS WITH COLUMNAR GRAINS
Authors: KIM D. H. , HWANG T. J. , SEONG W. K. , KANG W. N.
Published: July 2009

We studied temperature and magnetic-field dependence of grain boundary pinning effect in MgB 2 films with columnar grains by measuring the angular dependence of the resistivity and the critical current density (Jc). MgB 2 films grown by using a hybrid physical chemical vapor deposition method under appropriate conditions exhibit a peculiar columnar growth with their columns oriented along the c axis. The pinning effect by grain boundaries was manifested in the comparable or even higher J c for magnetic fields (H) parallel to the c axis (H‖c) than that for fields parallel to the ab plane (H‖ab) below certain temperature-dependent crossover fields. The crossover field, B cr , was around 1.6 T at 5 K and decreased to around 0.9 T at 30 K depending weakly on the sample characters, and B cr lay well below the upper critical fields in the phase diagram. Above B cr , J c for H‖c decreased very rapidly. The vortex spacing at B cr was closely correlated with the temperature dependence of the penetration depth, indicating that the degree of the vortex-vortex overlap is an important parameter to determine the number of vortices allowed per unit length of grain boundaries. Thus, B cr was thought to demarcate the accommodation capability of flux lines by the grain boundaries, and a rapid decrease of J c above B cr was ascribed to flux motion of the less strongly pinned vortices located away from the grain boundaries.
YBCO FILMS DOPING WITH SZO PARTICLES GROWN BY CHEMICAL SOLUTION DEPOSITION
Authors: LIU MIN , SHI DONGQI , LI QI , WANG LIN , YE SHUAI , SUO HONGLI , DOU SHIXUE
Published: July 2009

YBa 2 Cu 3 O 7-δ ( YBCO ) films with SrZrO 3 ( SZO ) doping have been prepared successfully by a non-vacuum, low cost, and easily scalable metal–organic deposition method, and their microstructures and physical properties were investigated. From the analysis of x-ray diffraction and φ-scan results, the doped films had sharp biaxial textures. Although the doped YBCO film had a wider critical temperature transition width than that of the un-doped YBCO film, the critical current density, J c , was significantly enhanced under applied fields as compared to the un-doped film. Furthermore, the ratio of J c , doped to J c , un-doped became gradually larger with increasing temperature and magnetic field, indicating that an effective pinning force was created by SZO doping. These results clearly demonstrate that there are appealing prospects for applications of the doped film in high magnetic fields and temperatures.
PHASE EVOLUTION AND MAGNETIC PROPERTIES OF FEPT-PTTE2 NANORODS
Authors: YAN QINGYU , LI AIDONG
Published: July 2009

FePt - PtTe 2 two phase nanorods have been produced by a polyol process. The shape and magnetic properties of two phase nanorods with different phase ratio are investigated. L10 phase transformation of FePt in the nanorods has been accomplished at annealing temperature as low as 400 °C with Hc above 500mT. High temperature annealing causes the disintegration of the nanorods due the melting/evaporation of Te element.
Triazolehemiporphyrazines: azaporphyrins with intrinsic low symmetry
Authors: Hahn Uwe , Rodríguez-Morgade M. Salomé
Published: July 2009

This highlight gives a brief summary of recent developments in the chemistry of hemiporphyrazines in the Iberian Peninsula, with a focus on triazolehemiporphyrazines. Among all porphyrinoids, hemiporphyrazines offer the advantage of exhibiting intrinsic D 2h symmetry and this feature has been exploited in the design of materials endowed with a variety of properties such as liquid crystalline behavior, electric and magnetic features and nonlinear optical performance, among others.
ECONOMICAL TORIC SPINES VIA CHEEGER'S INEQUALITY
Authors: ALON NOGA , KLARTAG BO'AZ
Published: July 2009

Let [Formula: see text] denote the graph whose set of vertices is {0,…,m - 1}d, where two distinct vertices are adjacent if and only if they are either equal or adjacent in the m-cycle Cm in each coordinate. Let [Formula: see text] denote the graph on the same set of vertices in which two vertices are adjacent if and only if they are adjacent in one coordinate in Cm and equal in all others. Both graphs can be viewed as graphs of the d-dimensional torus. We prove that one can delete [Formula: see text] vertices of G1 so that no topologically nontrivial cycles remain. This improves an O(d log 2 (3/2)md - 1) estimate of Bollobás, Kindler, Leader and O'Donnell. We also give a short proof of a result implicit in a recent paper of Raz: one can delete an [Formula: see text] fraction of the edges of G∞ so that no topologically nontrivial cycles remain in this graph. Our technique also yields a short proof of a recent result of Kindler, O'Donnell, Rao and Wigderson; there is a subset of the continuous d-dimensional torus of surface area [Formula: see text] that intersects all nontrivial cycles. All proofs are based on the same general idea: the consideration of random shifts of a body with small boundary and no nontrivial cycles, whose existence is proved by applying the isoperimetric inequality of Cheeger or its vertex or edge discrete analogues.
Assessment of Damage to Nucleic Acids and Repair Machinery inSalmonella typhimuriumExposed to Chlorine
Authors: Phe M. H. , Hajj Chehade M. , Guilloteau H. , Merlin C. , Block J. C.
Published: July 2009

Water disinfection is usually evaluated using mandatory methods based on cell culturability. However, such methods do not consider the potential of cells to recover, which should also be kept as low as possible. In this paper, we hypothesized that a successful disinfection is achieved only when the applied chlorine leads to both intracellular nucleic acid damage and strong alterations of the DNA repair machinery. Monitoring the SOS system responsiveness with aumuC'-‘lacZreporter fusion, we found that the expression of this important cellular machinery was altered after the beginning of membrane permeabilization but prior to the total decline of both the cell culturability and the nucleic acid integrity as revealed by Sybr-II staining. Rapid measurement of such nucleic acid alterations by fluorochrome-based staining could be used as an alternative method for assessing the effectiveness of disinfection with chlorine.
Rôle du microbiote dans les maladies inflammatoires de l’intestin
Authors: Chermesh Irit , Shamir Raanan
Published: July 2009

La maladie de Crohn et la rectocolite ulcéro-hémorragique sont des affections inflammatoires des voies digestives et représentent ensemble un spectre de maladies appelées maladies inflammatoires chroniques de l’intestin (MICI). L’intestin humain est colonisé par un microbiote commensal à des concentrations excédant le nombre de cellules de la totalité de l’organisme. Dans des conditions physiologiques normales, il existe une interaction entre ces bactéries et l’hôte humain dans le cadre d’un processus maintenant l’intégrité du système immunitaire dans les conditions normales et pathologiques. Le microbiote intestinal joue un rôle important dans les MICI. Des bactéries commensales et pathogènes interviennent dans l’étiologie des MICI, et le microbiote intestinal des patients atteints de ces maladies diffère de celui des témoins en bonne santé. Ces bactéries interviennent probablement dans l’installation de ces maladies comme dans leurs exacerbations. Il est donc logique de présumer qu’une manipulation du microbiote intestinal pourrait jouer un rôle préventif dans l’évolution des MICI et un rôle thérapeutique sur leurs exacerbations. Nous discuterons brièvement ici des domaines liés à l’étude du microbiote intestinal, à celles de l’interaction de celui-ci avec le système immunologique dans les MICI et du rôle du microbiote dans l’étiologie, les exacerbations et le traitement de ces maladies.
Enhanced Expressions of mRNA for Neuropeptide Y and Interleukin 1 Beta in Hypothalamic Arcuate Nuclei during Adjuvant Arthritis-Induced Anorexia in Lewis Rats
Authors: Stofkova Andrea , Haluzik Martin , Zelezna Blanka , Kiss Alexander , Skurlova Martina , Lacinova Zdenka , Jurcovicova Jana
Published: July 2009

Objective: Food intake is activated by hypothalamic orexigenic neuropeptide Y (NPY), which is mainly under the dual control of leptin and ghrelin. Rat adjuvant arthritis (AA), similarly as human rheumatoid arthritis, is associated with cachexia caused by yet unknown mechanisms. The aim of our study was to evaluate NPY expression in hypothalamic arcuate nuclei (nARC) under the conditions of AA-induced changes in leptin, ghrelin and adiponectin. Since IL-1β is involved in the central induction of anorexia, we studied its expression in the nARC as well. Methods: AA was induced to Lewis rats using complete Freund’s adjuvant. On days 12, 15 and 18 after complete Freund’s adjuvant injection, the levels of leptin, adiponectin, ghrelin and IL-1β were determined by RIA or ELISA. The mRNA expressions for NPY, leptin receptor (OB-R), ghrelin receptor (Ghsr) and IL-1β were determined by TaqMan RT-PCR from isolated nARC. Results: In AA rats, decreased appetite, body mass and epididymal fat stores positively correlated with reduced circulating and epididymal fat leptin and adiponectin. Ghrelin plasma levels were increased. In nARC, mRNA for OB-R, Ghsr and NPY were overexpressed in AA rats. AA rats showed overexpression of mRNA for IL-1β in nARC while circulating, and spleen IL-1β was unaltered. Conclusion: During AA, overexpression of orexigenic NPY mRNA in nARC along with enhanced plasma ghrelin and lowered leptin levels occur. Decreased food intake indicates a predominant effect of the anorexigenic pathway. Activated expression of IL-1β in nARC suggests its role in keeping AA-induced anorexia in progress. The reduction in adiponectin may also contribute to AA-induced anorexia.
Impact of Immunomodulatory Treatment on Leukocyte Cytokine Production in Multiple Sclerosis Patients and Healthy Donors
Authors: Reske Dirk , Thomas Anne V. , Petereit Hela-Felicitas , Fink Gereon R. , Schroeter Michael
Published: July 2009

Objectives: Treatment with interferon(IFN) β, glatiramer acetate (GLAT) and intravenous immunoglobulins (IVIG) alters the cytokine production in multiple sclerosis (MS) patients. To date, it is not clear whether the effect on cytokines varies among these drugs. Therefore, we analyzed the effects of these drugs on the cytokine profiles of MS patients as well as healthy controls. Methods: The in vitro effects of IFNβ, GLAT and IVIG on leukocyte subsets producing the p40 subunit of interleukin 12 (IL12p40), IFNγ, tumor necrosis factor (TNF) and interleukin (IL) 10 were assessed in 21 MS patients and 11 healthy volunteers using flow cytometry. Results: In peripheral vein blood of healthy volunteers, IVIG reduced IL12p40-producing monocytes (p = 0.003) and IFNγ in CD4+ lymphocytes (p = 0.003). IFNβ treatment increased the proportion of IFNγ-producing CD4+ lymphocytes (p = 0.003) whereas GLAT reduced TNF production (p = 0.012). In MS patients, IVIG induced a suppression of leukocytes producing IL12p40 (p < 0.001) and IFNγ (p = 0.001). IFNβ decreased monocytes producing IL12p40 (p < 0.001) and increased IL10 (p = 0.005). GLAT reduced IL12p40 (p < 0.001), IFNγ (p = 0.001 in CD4+ and CD8+ lymphocytes) and TNF production of leukocytes (p < 0.001). In addition, the baseline cytokine patterns were inherently different between individual MS patients. Conclusions: IFNβ, GLAT and IVIG had different effects on cytokine patterns, which might point towards different mechanisms of action. Since the baseline cytokine patterns differed among MS patients, the evaluation of the cytokine pattern might serve as a surrogate marker before starting immunomodulatory treatments and might be helpful to tailor MS therapy effectively to the needs of each individual patient.
Evaluation of the Elite Schools of Sport
Authors: Emrich Eike , Fröhlich Michael , Klein Markus , Pitsch Werner
Published: July 2009

The German Olympic sport federation considers elite sport schools (ESS) to be beneficial for talented young athletes by offering school education and optimal training conditions, enabling pupils to perform at their best. An evaluation of ESS institutions systematically analyzed empirical data on ascribed and achieved aims with collected individual and collective data using questionnaires. On an individual basis, school performances and post-school occupational prospects, as well as competitive success of participants in the 2004 Summer Olympics and the 2006 Winter Olympics were compared among ESS and non-ESS student-athletes. Age differences between the categories `continuous at ESS', `in stages at ESS' and `never at ESS' were not found. The results show that there was no difference in athletic performances between ESS pupils and others in the 2004 Summer Olympics, while in the 2006 Winter Olympics, there was a significant difference. Furthermore, there were no differences in school performances between the groups. Pupils at ESS often go on to pursue careers in the federal police and the armed forces, while many more non-ESS pupils work toward earning a university degree. The available data suggest that attending an ESS results in higher individual social costs which are not matched by comparable success in athletic competitions.
Red Feminism and Propaganda in Communist Media
Authors: Jung Woo Lee
Published: July 2009

This article discusses the representation of female boxers in the North Korean media. Communists proclaim the liberation of women as one of their major political aims, and the media's portrayal of female pugilists appears to adhere to this political notion. No negative or sexualized description can be found in the North Korean media coverage of female boxing. However, a deeper analysis reveals that the media in this communist state ideologically underline a broader political structure based on state patriarchy. Moreover, the political use of female boxing is evident. In this regard, the priority seems to be given to nationalism over feminism. With respect to this, this article contends that while the North Korean media representation of female sport highlights active and skilful female athletes, such a portrayal must be seen within the limit of broader patriarchal politics. Thus, media coverage of female sport in `actually existing communism' appears to differ considerably from the genuine sense of increasing the social status of women.
Fault Tolerance in Petascale/ Exascale Systems: Current Knowledge, Challenges and Research Opportunities
Authors: Cappello Franck
Published: July 2009

The emergence of petascale systems and the promise of future exascale systems have reinvigorated the community interest in how to manage failures in such systems and ensure that large applications, lasting several hours or tens of hours, are completed successfully. Most of the existing results for several key mechanisms associated with fault tolerance in high-performance computing (HPC) platforms follow the rollback—recovery approach. Over the last decade, these mechanisms have received a lot of attention from the community with different levels of success. Unfortunately, despite their high degree of optimization, existing approaches do not fit well with the challenging evolutions of large-scale systems. There is room and even a need for new approaches. Opportunities may come from different origins: diskless checkpointing, algorithmic-based fault tolerance, proactive operation, speculative execution, software transactional memory, forward recovery, etc. The contributions of this paper are as follows: (1) we summarize and analyze the existing results concerning the failures in large-scale computers and point out the urgent need for drastic improvements or disruptive approaches for fault tolerance in these systems; (2) we sketch most of the known opportunities and analyze their associated limitations; (3) we extract and express the challenges that the HPC community will have to face for addressing the stringent issue of failures in HPC systems.
Review: Do patients with functional gastrointestinal disorders have an altered gut flora?
Authors: Quigley Eamonn M.M.
Published: July 2009

The description of the de novo development of irritable bowel syndrome (IBS) following an episode of bacterial gastroenteritis (postinfectious IBS) illustrated the potential for a luminal factor (a bacterial pathogen) to cause this common gastrointestinal ailment. As a consequence of these and other observations as well as results of experiments involving animal models, the enteric flora and the immune response that it generates in the host have, somewhat surprisingly, come centre-stage in IBS research with their potential to induce the pathophysiological changes that are associated with IBS. While evidence for immune dysfunction both in the mucosa and systemically continues to accumulate, methodological limitations have hampered a full delineation of the nature of the microbiota in IBS. The latter is eagerly awaited and may yet provide a firm rationale for the use of certain probiotics and antibiotics in IBS, whose benefits have now been described with some consistency.
Review: Tools for the tract: understanding the functionality of the gastrointestinal tract
Authors: Kovatcheva-Datchary Petia , Zoetendal Erwin G. , Venema Koen , de Vos Willem M. , Smidt Hauke
Published: July 2009

The human gastrointestinal tract comprises a series of complex and dynamic organs ranging from the stomach to the distal colon, which harbor immense microbial assemblages that are known to be vital for human health. Until recently, most of the details concerning our gut microbiota remained obscure. Over the past several years, however, a number of crucial technological and conceptual innovations have been introduced to shed more light on the composition and functionality of human gut microbiota. Recently developed high throughput approaches, including next-generation sequencing technologies and phylogenetic microarrays targeting ribosomal RNA gene sequences, allow for comprehensive analysis of the diversity and dynamics of the gut microbiota composition. Nevertheless, most of the microbes especially in the human large intestine still remain uncultured, and the in situ functions of distinct groups of the gut microbiota are therefore largely unknown, but pivotal to the understanding of their role in human physiology. Apart from functional and metagenomics approaches, stable isotope probing is a promising tool to link the metabolic activity and diversity of microbial communities, including yet uncultured microbes, in a complex environment. Advancements in current stable isotope probing approaches integrated with the application of high-throughput diagnostic microarray-based phylogenetic profiling and metabolic flux analysis should facilitate the understanding of human microbial ecology and will enable the development of innovative strategies to treat or prevent intestinal diseases of as yet unknown etiology.