bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Geographical Origin on the Conjugated Linolenic Acid of Trichosanthes kirilowii Maxim Seed Oil
Authors: Yang Jing , Zhou Ciqin , Yuan Gaofeng , Li Duo
Published: August 2011

Trichosanthes kirilowii Maxim (T. kirilowii) seeds from four geographical locations (Changxing, Quzhou, Yuexi, Dongzhi) contained 26.15–49.41% oil and 28.68–37.90% protein. The seed oil was distinguished by the conjugated linolenic acids, punicic acid (PA) and α‐eleostearic acid (α‐ESA). The main fatty acids in T. kirilowii seed oils were ranked in the following order: punicic acid (33.09–39.15%), linolenic acid (33.77–38.66%), oleic acid (15.15–24.88%), palmitic acid (2.36–4.86%). PA was the main isomer of CLNA (33.09–39.15%). No significant differences were found either in PA content or in α‐ESA content of T. kirilowii seed from these geographical locations. Little difference was observed in the quantitative composition of the lipid contents of seeds from different geographical locations. The α‐tocopherol content of T. kirilowii seed ranged from 6.34 to 31.74 mg/100 g, with the highest levels in Changxing seeds. The present results showed that T. kirilowii seeds were especially rich in PA, and their contents were not influenced by the geographical locations. Variation in some proximate compositions by geographical locations may be caused by ecological conditions, temperature, climate condition, technical and cultural conditions.
Watershed Prioritization Using Morphometric and Land Use/Land Cover Parameters: A Remote Sensing and GIS Based Approach
Authors: Javed Akram , Khanday Mohd Yousuf , Rais Subah
Published: August 2011

Jaggar watershed is a constituent of the Gambhir river basin, in eastern Rajasthan and covers an area of 352.82 km2, representing arid climate. The drainage network is dendritic to sub-dendritic pattern however parallel to sub-parallel has also developed locally. The Jaggar watershed has been divided into fourteen sub-watersheds, designated as SW1 to SW14, for prioritization purpose. The prioritization of the sub-watersheds has been done on the basis of morphometric analysis and land use/land cover categories. Various morphometric parameters (linear and shape) have been determined for each sub-watershed and assigned rank on the basis of value/relationship with erodibility so as to arrive at a compound value for final ranking of the sub-watersheds. Land use/land cover mapping has been carried out using IRS LISS III data of 1998. Based on morphometric and land use/land cover analysis and their ranks, the sub-watersheds have been classified into four categories as very high, high, medium and low in terms of priority for conservation and management of natural resources. The prioritization results based on morphometry reveal that only SW7 and SW10 fall under very high priority, whereas SW6, SW11 and SW13 fall under very high priority on the basis of land use/land cover analysis. However on the integration of morphometry and land use/land cover only SW14 show common priority whereas rest have little or no correlation.
Diet quality and change in anthropometric measures: 15-year longitudinal study in Australian adults
Authors: Arabshahi Simin , van der Pols Jolieke C. , Williams Gail M. , Marks Geoffrey C. , Lahmann Petra H.
Published: August 2011

Evidence from longitudinal studies on the association between diet quality and change in anthropometric measures is scarce. We therefore investigated the relationship between a recently developed food-based dietary index and change in measured BMI and waist circumference (WC) in Australian adults (1992–2007). We used data from the Australian population-based Nambour Skin Cancer Study comprising 1231 adults aged 25–75 years at baseline (1992). We applied generalised estimating equations (GEE) to examine the association between diet quality and change in anthropometric measures. Dietary intake was assessed by an FFQ in 1992, 1996 and 2007. Diet quality was estimated using the dietary guideline index (DGI), developed to reflect the dietary guidelines for Australian adults; a higher score indicating increased compliance. Multivariable models, stratified by sex, were adjusted for sociodemographic and lifestyle characteristics. We show that men with higher diet quality had a lower gain in BMI as compared to those with low diet quality during the 15-year follow-up. In a multivariable adjusted model, as compared to men in quartile 1 (reference), those in the highest quartile had the lowest gain in BMI (mean (95 % CI): 0·05 (0·00, 0·09) v. 0·11 (0·06, 0·16) kg/m2 per year, P =0·01). Diet quality was inversely, but non-significantly associated with change in WC. In women, DGI score was unrelated to change in any body measure. Energy underreporting did not explain the lack of association. We conclude that adherence to a high-quality diet according to Australian dietary guidelines leads to lower gain in BMI and WC in middle-aged men, but not in women.
Investigating preference-performance relationships in aboveground-belowground life cycles: a laboratory and field study with the vine weevil (Otiorhynchus sulcatus)
Authors: Clark K.E. , Hartley S.E. , Brennan R.M. , MacKenzie K. , Johnson S.N.
Published: August 2011

The preference-performance hypothesis has principally considered insect herbivores with aboveground lifecycles, although the hypothesis could be equally relevant to insects with life stages occurring both aboveground and belowground. Moreover, most studies have focussed on either laboratory or field experiments, with little attempt to relate the two. In this study, the preference-performance hypothesis was examined in an aboveground-belowground context in the laboratory using the vine weevil (Otiorhynchus sulcatus(F.)) (Coleoptera: Curculionidae) and two cultivars of red raspberry (Rubus idaeus), Glen Rosa and Glen Ample. A two-year field study (2008–2009) was also undertaken to characterise the population dynamics of adult weevils on the two raspberry cultivars. Larval performance (abundance and mass) differed significantly between Glen Rosa and Glen Ample, with Glen Rosa resulting in 26% larger but 56% fewer larvae compared to Glen Ample. Larval abundances were significantly and positively correlated with root nitrogen and magnesium concentrations, but negatively correlated with root iron. However, concentrations of these minerals were not significantly different in the two cultivars. Adult weevils did not preferentially select either of the two cultivars for egg laying (laying 3.08 and 2.80 eggs per day on Glen Ample and Glen Rosa, respectively), suggesting that there was no strong preference-performance relationship between adult vine weevils and their belowground offspring. Field populations of adult vine weevils were significantly higher on Glen Ample than Glen Rosa, which may reflect the higher larval survival on Glen Ample observed in laboratory experiments.
Studying Attitudes to Work Worldwide, 1500–1650: Concepts, Sources, and Problems of Interpretation
Authors: van der Linden Marcel
Published: August 2011

The period 1500–1650 was characterized by huge global transformations. These had a major impact on a wide range of societal forms and cultures. As a result, different work ethics clashed and formed hybrid combinations, and new work ethics came into being during many-sided confrontations. The question of how the labouring poor in different parts of the world experienced these changes in the context of their work is an extremely difficult one. The present essay attempts to define a number of key concepts (“work”, “attitude”); it evaluates critically the various sources which might give us an insight into attitudes to work; and it reflects on interpretative difficulties. The essay concludes by presenting a few substantive hypotheses.
Composition, indigenous proteolytic enzymes and coagulating behaviour of ewe milk as affected by somatic cell count
Authors: Albenzio Marzia , Santillo Antonella , Caroprese Mariangela , Schena Laura , Russo Donatella Esterina , Sevi Agostino
Published: August 2011

This study was undertaken to assess the effect of somatic cell count in ewe milk on i) composition and hygienic traits; ii) plasmin, cathepsin and elastase activities; iii) leukocyte differential count; iv) renneting parameters. Individual ewe milk samples were grouped according to somatic cell count (SCC) into five classes: SC300 (<300 000 cells/ml), SC500 (from 301 000 to 500 000 cells/ml), SC1000 (from 501 000 to 1 000 000 cells/ml), SC2000 (from 1 001 000 to 2 000 000 cells/ml) and SC>2000 (>2 001 000 cells/ml). Individual milk samples were analysed for pH, chemical composition, microbial features, indigenous proteolytic enzymes, differential leukocyte population, and renneting parameters. Milk yield, lactose, protein, non casein nitrogen, microbial features were affected by SCC level. Plasmin and elastase activities were the highest in samples with more than 1 000 000 cells/ml; plasmin had intermediate values in samples with 300 000 to 1 000 000 cells/ml and the lowest in samples with less than 300 000 cells/ml of milk. Cathepsin D showed significantly lower values in SC300 and SC1000 classes than in SC500, SC2000 and SC>2000 classes. The highest percentages of lymphocyte were found in samples with less than 1 000 000 cells/ml, while the highest levels of polymorphonuclear leukocyte were found in samples with more than 1 000 000 cells/ml of milk. Longer clotting time was found in SC>2000 samples, while reduced clot firmness was observed in SC500 and SC>2000 samples. Results on milk yield and on compositional parameters evidenced an impairment of udder efficiency in ewe milk samples starting from 300 000 cells/ml. Plasmin activity in milk can be considered as a marker of the synthetic and secreting ability of the mammary gland; furthermore plasmin and elastase were consistent with the health status of the udder. Finally cathepsin D played a role in the worsening of renneting properties of ewe milk.
Intranasal immunization with LACK-DNA promotes protective immunity in hamsters challenged withLeishmania chagasi
Authors: DE OLIVEIRA GOMES DANIEL CLAUDIO , DA SILVA COSTA SOUZA BEATRIZ LILIAN , DE MATOS GUEDES HERBERT LEONEL , LOPES ULISSES GAZOS , ROSSI-BERGMANN BARTIRA
Published: August 2011

LACK (Leishmaniaanalogue of the receptor kinase C) is a conserved protein in protozoans of the genusLeishmaniawhich is associated with the immunopathogenesis and susceptibility of BALB/c mice toL. majorinfection. Previously, we demonstrated that intranasal immunization with a plasmid carrying the LACK gene ofLeishmania infantum(LACK-DNA) promotes protective immunity in BALB/c mice againstLeishmania amazonensisandLeishmania chagasi.In the present study, we investigated the protective immunity achieved in hamsters intranasally vaccinated with 2 doses of LACK-DNA (30μg). Compared with controls (PBS and pCI-neo plasmid), animals vaccinated with LACK-DNA showed significant reduction in parasite loads in the spleen and liver, increased lymphoproliferative response and increased nitric oxide (NO) production by parasite antigen-stimulated splenocytes. Furthermore, hamsters vaccinated with LACK-DNA presented high IgG and IgG2a serum levels when compared to control animals. Our results showed that intranasal vaccination with LACK-DNA promotes protective immune responses in hamsters and demonstrated the broad spectrum of intranasal LACK-DNA efficacy in different host species, confirming previous results in murine cutaneous and visceral leishmaniasis.
Un paseo por la literatura sobre capital social desde una perspectiva económica
Authors: Felis-Rota Marta
Published: August 2011

This essay considers the literature on the topic of social capital in relation to the economic science, and opens new perspectives of research in this area. This essay starts with a walk through the history of economic thought that has influenced social capital literature. Afterwards, the reader will find a discussion on different perspectives of research that have been followed up to now and some others in relation with the microeconomic foundations of the concept of social capital, and its connexion with economic growth and finance.
Human security and the rise of the social
Authors: OWENS PATRICIA
Published: September 2011

As the concept of human security has become part of the mainstream discourse of international politics it should be no surprise that both realist and critical approaches to international theory have found the agenda wanting. This article seeks to go beyond both the realist and biopolitical critiques by situating all three – political realism, biopolitics and human security – within the history and theory of the modernrise of the socialrealm from late eighteenth and nineteenth century Europe. Human security is the further expansion ofsocialforms of governance under capitalism, more specifically a form ofsocialpolitikthanrealpolitikor biopolitics. Drawing on the work of historical sociologist Robert Castel and political theorist Hannah Arendt, the article develops an alternative framework with which to question the extent to which ‘life’ has become the subject of global intervention through the human security agenda.
Comments on “Design and analysis of a totally decoupled 3-DOF spherical parallel manipulator” by D. Zhang and F. Zhang (Robotica, Available on CJO 19 Nov, 2010, doi:10.1017/S0263574710000652)
Authors: Kong Xianwen , Gosselin Clément , Carricato Marco
Published: September 2011

D. Zhang and F. Zhang addressed the issue of designing and analyzing totally decoupled 3-DOF spherical parallel manipulators (SPMs) and concluded that the SPMs in Figs. 5(a) and 5(b) of ref. [1] are completely decoupled and fully isotropic (see Abstract, Section 5, and Conclusions in ref. [1]). This topic is of great interest to researchers working in the general area of parallel mechanisms. However, we disagree with the authors of ref. [1] on their conclusion.
Construction of Ipr1 expression vector and development of cloned embryos in vitro
Authors: Song Yongli , He Xiaoning , Hua Song , Lan Jie , Liu Yonggang , Cheng Pang , Zhang Hailin , Li Jixia , He Xiaoying , Liu Jun , Zhang Yong
Published: August 2011

The purpose of this study was to prepare intracellular pathogen resistance 1 (Ipr1) transgenic donor cells for somatic cell nuclear transfer (SCNT). Based on our current understanding of Ipr1, a macrophage special expression vector pSP–EGFP–Ipr1was constructed. Bovine fetal fibroblasts were transfected with pSP-EGFP-Ipr1. The green fluorescent protein (GFP)-expressing cells were selected and transferred into enucleated bovine oocytes. Then, the rates of oocyte cleavage and blastocyst formation of transgenic cells and non-transgenic cells were observed, respectively. The results showed that reconstructed embryos derived from transgenic cells could successfully develop into blastocysts, most of which were GFP-positive. This study may provide cloned embryos for the production of anti-tuberculosis transgenic animals.
3D numerical MHD modeling of sunspots with radiation transport
Authors: Rempel Matthias
Published: August 2011

Sunspot fine structure has been modeled in the past by a combination of idealized magneto-convection simulations and simplified models that prescribe the magnetic field and flow structure to a large degree. Advancement in numerical methods and computing power has enabled recently 3D radiative MHD simulations of entire sunspots with sufficient resolution to address details of umbral dots and penumbral filaments. After a brief review of recent developments we focus on the magneto-convective processes responsible for the complicated magnetic structure of the penumbra and the mechanisms leading to the driving of strong horizontal outflows in the penumbra (Evershed effect). The bulk of energy and mass is transported on scales smaller than the radial extent of the penumbra. Strong horizontal outflows in the sunspot penumbra result from a redistribution of kinetic energy preferring flows along the filaments. This redistribution is facilitated primarily through the Lorentz force, while horizontal pressure gradients play only a minor role. The Evershed flow is strongly magnetized: While we see a strong reduction of the vertical field, the horizontal field component is enhanced within filaments.
Heating of coronal active regions
Authors: Gómez Daniel O.
Published: August 2011

Recent observations of coronal loops in solar active regions show that their heating must be a truly dynamic process. Even though it seems clear that the energy source is the magnetic field that confines the coronal plasma, the details of how it dissipates are still a matter of debate. In this presentation we review the theoretical models of coronal heating, which have been traditionally clasified as DC or AC depending on the electrodynamic response of the loops to the photospheric driving motions.

Also, we show results from numerical simulations of the internal dynamics of coronal loops within the framework of the reduced MHD approximation. These simulations indicate that the application of a stationary velocity field at the photospheric boundary leads to a turbulent stationary regime after several photospheric turnover times. Once this turbulent regime is set, both DC and AC stresses dissipate at faster rates as a result of a direct energy cascade.
Automated sunspot detection and the evolution of sunspot magnetic fields during solar cycle 23
Authors: Watson Fraser , Fletcher Lyndsay
Published: August 2011

The automated detection of solar features is a technique which is relatively underused but if we are to keep up with the flow of data from spacecraft such as the recently launched Solar Dynamics Observatory, then such techniques will be very valuable to the solar community. Automated detection techniques allow us to examine a large set of data in a consistent way and in relatively short periods of time allowing for improved statistics to be carried out on any results obtained. This is particularly useful in the field of sunspot study as catalogues can be built with sunspots detected and tracked without any human intervention and this provides us with a detailed account of how various sunspot properties evolve over time. This article details the use of the Sunspot Tracking And Recognition Algorithm (STARA) to create a sunspot catalogue. This catalogue is then used to analyse the magnetic fields in sunspot umbrae from 1996-2010, taking in the whole of solar cycle 23.
Rotational modulation, shear, and cyclic activity in HII 1883
Authors: Milingo J. B. , Saar S. H. , Marschall L. A. , Stauffer J. R.
Published: August 2011

We present a 30 year compilation of V-band differential photometry for the Pleiades K dwarf HII 1883. HII 1883 has an average rotational period 〈Prot〉 of ~0.235d and displays rotational modulation due to non-uniform surface brightness as large as 0.2 magnitudes in V. Preliminary work yields a cycle period of ~9yrs and rotational shear δProt/〈Prot〉 considerably less than solar. With such a long baseline of data available we can explore many aspects of the star's photometric variability. We present studies of the variation of the rotational modulation amplitude, 〈V〉, and Prot over the cycle.
Stellar activity, differential rotation, and exoplanets
Authors: Lanza A. F.
Published: August 2011

The photospheric spot activity of some of the stars with transiting planets discovered by the CoRoT space experiment is reviewed. Their out-of-transit light modulations are fitted by a spot model previously tested with the total solar irradiance variations. This approach allows us to study the longitude distribution of the spotted area and its variations versus time during the five months of a typical CoRoT time series. The migration of the spots in longitude provides a lower limit for the surface differential rotation, while the variation of the total spotted area can be used to search for short-term cycles akin the solar Rieger cycles. The possible impact of a close-in giant planet on stellar activity is also discussed.
Solar activity due to magnetic complexity of active regions
Authors: Schmieder Brigitte , Mandrini Cristina , Chandra Ramesh , Démoulin Pascal , Török Tibor , Pariat Etienne , Uddin Wahab
Published: August 2011

Active regions (ARs), involved in the Halloween events during October-November 2003, were the source of unusual activity during the following solar rotation. The flares on 18-20 November 2003 that occur in the AR NOAA10501 were accompanied by coronal mass ejections associated to some particularly geoeffective magnetic clouds.

Our analysis of the magnetic flux and helicity injection revealed that a new emerging bipole and consequent shearing motions continuously energized the region during its disk passage. The stored energy was eventually released through the interaction of the various systems of magnetic loops by several magnetic reconnection events. Active events on November 18 (filament eruptions and CMEs) were originated by shearing motions along a section of the filament channel that injected magnetic helicity with sign opposite to that of the AR. Two homologous flares, that occurred on November 20, were apparently triggered by different mechanisms as inferred from the flare ribbons evolution (filament eruption and CMEs). We studied in detail the behaviour of two North-South oriented filaments on November 20 2003. They merged and split following a process suggestive of ‘sling-shot’ reconnection between two coronal flux ropes. We successfully tested this scenario in a 3D MHD simulation that is presented in this paper.
Evolution of twist-shear and dip-shear in flaring active region NOAA 10930
Authors: Gosain Sanjay , Venkatakrishnan P.
Published: August 2011

We study the evolution of magnetic shear angle in a flare productive active region NOAA 10930. The magnetic shear angle is defined as the deviation in the orientation of the observed magnetic field vector with respect to the potential field vector. The shear angle is measured in horizontal as well as vertical plane. The former is computed by taking the difference between the azimuth angles of the observed and potential field and is called the twist-shear, while the latter is computed by taking the difference between the inclination angles of the observed and potential field and is called the dip-shear. The evolution of the two shear angles is then tracked over a small region located over the sheared penumbra of the delta sunspot in NOAA 10930. We find that, while the twist-shear shows an increasing trend after the flare the dip-shear shows a significant drop after the flare.
An “A star” on an M star during a flare within a flare
Authors: Kowalski Adam F. , Hawley Suzanne L. , Holtzman Jon A. , Wisniewski John P. , Hilton Eric J.
Published: August 2011

M dwarfs produce explosive flare emission in the near-UV and optical continuum, and the mechanism responsible for this phenomenon is not well-understood. We present a near-UV/optical flare spectrum from the rise phase of a secondary flare, which occurred during the decay of a much larger flare. The newly formed flare emission resembles the spectrum of an early-type star, with the Balmer lines and continuum in absorption. We model this observation phenomenologically as a temperature bump (hot spot) near the photosphere of the M dwarf. The amount of heating implied by our model (ΔTphot ~ 16,000 K) is far more than predicted by chromospheric backwarming in current 1D RHD flare models (ΔTphot ~ 1200 K).
Sunspots at centimeter wavelengths
Authors: Kundu Mukul R. , Lee Jeongwoo
Published: August 2011

The early solar observations of Covington (1947) established a good relation between 10.7 cm solar flux and the presence of sunspots on solar disk. The first spatially resolved observation with a two-element interferometer at arc min resolution by Kundu (1959) found that the radio source at 3 cm has a core-halo structure; the core is highly polarized and corresponds to the umbra of a sunspot with magnetic fields of several hundred gauss, and the halo corresponds to the diffuse penumbra or plage region. The coronal temperature of the core was interpreted as due to gyroresonance opacity produced by acceleration of electrons gyrating in a magnetic field. Since the opacity is produced at resonant layers where the frequency matches harmonics of the gyrofrequency, the radio observation could be utilized to measure the coronal magnetic field. Since this simple interferometric observation, the next step for solar astronomers was to use arc second resolution offered by large arrays at cm wavelengths such as Westerbrock Synthesis Radio Telescope and the Very Large Array, which were primarily built for cosmic radio research. Currently, the Owens Valley Solar Array operating in the range 1-18 GHz and the Nobeyama Radio Heliograph at 17 and 34 GHz are the only solar dedicated radio telescopes. Using these telescopes at multiple wavelengths it is now possible to explore three dimensional structure of sunspot associated radio sources and therefore of coronal magnetic fields. We shall present these measurements at wavelengths ranging from 1.7 cm to 90 cm and associated theoretical developments.
First solar butterfly diagram from Schwabe's observations in 1825–1867
Authors: Arlt Rainer , Abdolvand Anastasia
Published: August 2011

The original sunspot observations by Samuel Heinrich Schwabe of 1825–1867 were digitized and a first subset of spots was measured. In this initial project, we determined more than 14 000 sunspot positions and areas comprising about 11% of the total amount of spots available from that period. The resulting butterfly diagram has a typical appearance, but with evident north-south asymmetries.
Flare induced penumbra formation in the sunspot of NOAA 10838
Authors: Padinhatteeri Sreejith , K. Sankarasubramanian
Published: August 2011

We have observed formation of penumbrae on a pore in the active region NOAA10838 using Dunn Solar Telescope at NSO, Sunpot, USA. Simultaneous observations using different instruments (DLSP, UBF, Gband and CaK) provide us with vector magnetic field at photosphere, intensity images and Doppler velocity at different heights from photosphere to chromosphere. Results from our analysis of this particular data-set suggests that penumbrae are formed as a result of relaxation of magnetic field due to a flare happening at the same time. Images in Hα show the flare (C 2.9 as per GOES) and vector magnetic fields show a re-orientation and reduction in the global α value (a measure of twist). We feel such relaxation of loop structures due to reconnections or flare could be one of the way by which field lines fall back to the photosphere to form penumbrae.
Are the photospheric sunspots magnetically force-free in nature?
Authors: Tiwari Sanjiv Kumar
Published: August 2011

In a force-free magnetic field, there is no interaction of field and the plasma in the surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. The computation of many magnetic parameters like magnetic energy, gradient of twist of sunspot magnetic fields (computed from the force-free parameter α), including any kind of extrapolations heavily hinge on the force-free approximation of the photospheric magnetic fields. The force-free magnetic behaviour of the photospheric sunspot fields has been examined by Metcalf et al. (1995) and Moon et al. (2002) ending with inconsistent results. Metcalf et al. (1995) concluded that the photospheric magnetic fields are far from the force-free nature whereas Moon et al. (2002) found the that the photospheric magnetic fields are not so far from the force-free nature as conventionally regarded. The accurate photospheric vector field measurements with high resolution are needed to examine the force-free nature of sunspots. We use high resolution vector magnetograms obtained from the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard Hinode to inspect the force-free behaviour of the photospheric sunspot magnetic fields. Both the necessary and sufficient conditions for force-freeness are examined by checking global as well as as local nature of sunspot magnetic fields. We find that the sunspot magnetic fields are very close to the force-free approximation, although they are not completely force-free on the photosphere.
Subsurface flows associated with rotating sunspots
Authors: Jain Kiran , Komm Rudolf , Hernández Irene González , Tripathy Sushant C. , Hill Frank
Published: August 2011

In this paper, we compare components of the horizontal flow below the solar surface in and around regions consisting of rotating and non-rotating sunspots. Our analysis suggests that there is a significant variation in both components of the horizontal flow at the beginning of sunspot rotation as compared to the non-rotating sunspot. The flows in surrounding areas are in most cases relatively small. However, there is a significant influence of the motion on flows in an area closest to the sunspot rotation.
A theoretical model of torsional oscillations from a flux transport dynamo model
Authors: Chatterjee Piyali , Chakraborty Sagar , Choudhuri Arnab Rai
Published: August 2011

Assuming that the torsional oscillation is driven by the Lorentz force of the magnetic field associated with the sunspot cycle, we use a flux transport dynamo to model it and explain its initiation at a high latitude before the beginning of the sunspot cycle.
The dependence of maximum starspot amplitude and the amplitude distribution on stellar properties
Authors: Saar Steven H. , Dyke Michelle , Meibom Søren , Barnes Sydney A.
Published: August 2011

We combine photometric data from field stars, plus over a dozen open clusters and associations, to explore how the maximum photometric amplitude (Amax) and the distribution of amplitudes varies with stellar properties. We find a complex variation of Amax with inverse Rossby number Ro−1, which nevertheless can be modeled well with a simple model including an increase in Amax with rotation for low Ro−1, and a maximum level. Amax may then be further affected by differential rotation and a decline at the highest Ro−1. The distribution of Aspot below Amax varies with Ro−1 : it peaks at low Aspot with a long tail towards Amax for low Ro−1, but is more uniformly distributed at higher Ro−1. We investigate further dependences of the Aspot distributions on stellar properties, and speculate on the source of these variations.
The effects of star spots on transit photometry
Authors: Hodgson John R. , Christian Damian J.
Published: August 2011

We have undertaken an observational program to photometrically monitor several transiting planet host stars. The Rabus et al. result for TrES-1 showed the dramatic effects star spots can have on transit photometry. We will investigate the effects of spots on transit light curves and estimates of planetary radii. The observed spot patterns will be used to derive the rotational periods of our sample. Our sample includes several of the newly discovered transiting ESPs from the SuperWASP, HAT, TrES, and Kepler projects.
Adaptation, redundancy or resilience
Authors: van Helden Paul
Published: September 2011

Diversity creates resilience both in ecosystems and living organism. Yet, although genetic diversity protects organisms from many diseases and disorders, it also makes it much harder for geneticist to identify the risk factors that lead to common diseases.
A trinuclear bright red luminophore containing cyclometallated Ir(iii) motifs
Authors: Chandrasekhar Vadapalli , Wahidur Rahaman S. M. , Hajra Tanima , Das Dipak , Ghatak Tapas , Rather Shahnawaz R. , Sen Pratik , Bera Jitendra K.
Published: August 2011

A trinuclear cyclometallated ‘Ir(ppy)2’ complex bridged by naphthyridine-triazole is a bright red luminophore whereas the mononuclear complex bearing naphthyridine-pyrazine ancillary ligand emits in the green region.
Reduction in BACE1 decreases body weight, protects against diet-induced obesity and enhances insulin sensitivity in mice
Authors: Meakin Paul J. , Harper Alex J. , Hamilton D. Lee , Gallagher Jennifer , McNeilly Alison D. , Burgess Laura A. , Vaanholt Lobke M. , Bannon Kirsten A. , Latcham Judy , Hussain Ishrut , Speakman John R. , Howlett David R. , Ashford Michael L.J.
Published: September 2011

Insulin resistance and impaired glucose homoeostasis are important indicators of Type 2 diabetes and are early risk factors of AD (Alzheimer's disease). An essential feature of AD pathology is the presence of BACE1 (β-site amyloid precursor protein-cleaving enzyme 1), which regulates production of toxic amyloid peptides. However, whether BACE1 also plays a role in glucose homoeostasis is presently unknown. We have used transgenic mice to analyse the effects of loss of BACE1 on body weight, and lipid and glucose homoeostasis. BACE1−/− mice are lean, with decreased adiposity, higher energy expenditure, and improved glucose disposal and peripheral insulin sensitivity than wild-type littermates. BACE1−/− mice are also protected from diet-induced obesity. BACE1-deficient skeletal muscle and liver exhibit improved insulin sensitivity. In a skeletal muscle cell line, BACE1 inhibition increased glucose uptake and enhanced insulin sensitivity. The loss of BACE1 is associated with increased levels of UCP1 (uncoupling protein 1) in BAT (brown adipose tissue) and UCP2 and UCP3 mRNA in skeletal muscle, indicative of increased uncoupled respiration and metabolic inefficiency. Thus BACE1 levels may play a critical role in glucose and lipid homoeostasis in conditions of chronic nutrient excess. Therefore strategies that ameliorate BACE1 activity may be important novel approaches for the treatment of diabetes.
Hypoxia and reoxygenation modulate the arrhythmogenic activity of the pulmonary vein and atrium
Authors: Lin Yung-Kuo , Lai Mei-Shou , Chen Yao-Chang , Cheng Chen-Chuan , Huang Jen-Hung , Chen Shih-Ann , Chen Yi-Jen , Lin Cheng-I
Published: September 2011

Ischaemia and reperfusion contribute to the genesis of AF (atrial fibrillation). PVs (pulmonary veins) and the atria are important foci for AF initiation and maintenance. However, the effect of ischaemia and reperfusion on PVs and the atria has not yet been fully elucidated. In the present study, conventional microelectrodes were used to record the APs (action potentials) in isolated rabbit PV, LA (left atrium) and RA (right atrium) specimens during hypoxia and reoxygenation, and pharmacological interventions. Hypoxia reduced the PV beating rates from 1.8±0.1 to 1.3±0.2 and 0.8±0.1 Hz at 30 and 60 min respectively (n=8, P<0.005), and induced EAD (early after depolarization) in three (37.5%) of the PVs and DAD (delayed after depolarization) in one (12.5%) of the PVs. Reoxygenation increased the PV spontaneous rate to 1.4±0.2 Hz (P<0.05) and induced PV burst firings (3.5±0.1 Hz, P<0.001) in six (75%) of the PVs. Hypoxia shortened the AP duration in the LA and PVs, but not in the RA. Pretreatment with glibenclamide attenuated hypoxia-induced decreases in the PV spontaneous activity and the shortening of the LA and PV AP duration. Similar to those in hypoxia, the KATP (ATP-sensitive potassium) channel opener pinacidil (30 μM) decreased PV spontaneous activity and shortened the AP duration. Pretreatment with 5 mM N-MPG [N-(mercaptopropionyl)glycine; a hydroxyl (•OH) free-radical scavenger] or 300 μM chloramphenicol [a cytochrome P450 inhibitor that reduces ROS (reactive oxygen species)] attenuated the rate changes induced by hypoxia and reoxygenation, and also decreased the burst firing incidence. In conclusion, hypoxia and reoxygenation significantly increased PV arrhythmogenesis and induced different electrophysiological responses in the RA and LA, which may play a role in the pathophysiology of AF.
Self-consistent meta-generalized gradient approximation study of adsorption of aromatic molecules on noble metal surfaces
Authors: Ferrighi Lara , Madsen Georg K. H. , Hammer Bjørk
Published: August 2011

The adsorption of benzene, pyridine, and two nucleobases on the Au(111) surface has been investigated using a fully relaxed, self-consistent meta-generalized gradient approximation (meta-GGA) density functional theory setup with the M06-L functional. The meta-GGA based molecule-surface separations are shortened and the adsorption bond strengths of the molecules are greatly improved over the virtually non-interacting results obtained when using a plain GGA exchange-correlation functional. The nucleobases containing oxygen atoms show higher corrugation with adsorption site and orientation than the other aromatic molecules considered. The adsorption of pentacene is studied on Au, Ag, and Cu surfaces. In agreement with experiment, the adsorption energies are found to increase with decreasing nobleness, but the dependency is underestimated. We point out how the kinetic energy density can discriminate between covalent and non-covalent bonding regions of orbital overlap.
Sub-pixel porosity revealed by x-ray scatter dark field imaging
Authors: Revol V. , Jerjen I. , Kottler C. , Schütz P. , Kaufmann R. , Lüthi T. , Sennhauser U. , Straumann U. , Urban C.
Published: September 2011

X-ray scatter dark field imaging based on the Talbot-Lau interferometer allows for the measurement of ultra–small angle x-ray scattering. The latter is related to the variations in the electron density in the sample at the sub- and micron-scale. Therefore, information on features of the object below the detector resolution can be revealed. In this article, it is demonstrated that scatter dark field imaging is particularly adapted to the study of a material’s porosity. An interferometer, optimized for x-ray energies around 50 keV, enables the investigation of aluminum welding with conventional laboratory x-ray tubes. The results show an unprecedented contrast between the pool and the aluminum workpiece. Our conclusions are confirmed due to micro-tomographic three-dimensional reconstructions of the same object with a microscopic resolution.
Low energy Xe milling for the quantitative profiling of active dopants by off-axis electron holography
Authors: Cooper David , Hartmann Jean-Michel , Gambacorti Narciso
Published: September 2011

Off-axis electron holography is a powerful technique that can be used to measure the active dopants in semiconductors. The preparation of thin transmission electron microscopy specimens containing nm-scale regions of interest is extremely challenging and as a consequence ion milling is an essential tool. The exposure of doped specimens to energetic ions creates defects deep in the specimens that trap the active dopants, being the principle cause of what is known as the inactive region. The inactive thickness leads to an underestimation of the dopant potential in the specimens. Here we show that this artifact can be significantly reduced from 140 nm for specimens prepared using only Ga ions at 30 kV to only 10 nm by preparing specimens using 1.5 keV Xe ions for specimens containing p-n junctions with dopant concentrations of 2 × 1018 cm−3.
First-order virial expansion of short-time diffusion and sedimentation coefficients of permeable particles suspensions
Authors: Cichocki Bogdan , Ekiel-Jeżewska Maria L. , Nägele Gerhard , Wajnryb Eligiusz
Published: September 2011

For suspensions of permeable particles, the short-time translational and rotational self-diffusion coefficients, and collective diffusion and sedimentation coefficients are evaluated theoretically. An individual particle is modeled as a uniformly permeable sphere of a given permeability, with the internal solvent flow described by the Debye-Bueche-Brinkman equation. The particles are assumed to interact non-hydrodynamically by their excluded volumes. The virial expansion of the transport properties in powers of the volume fraction is performed up to the two-particle level. The first-order virial coefficients corresponding to two-body hydrodynamic interactions are evaluated with very high accuracy by the series expansion in inverse powers of the inter-particle distance. Results are obtained and discussed for a wide range of the ratio, x, of the particle radius to the hydrodynamic screening length inside a permeable sphere. It is shown that for x>rsim10, the virial coefficients of the transport properties are well-approximated by the hydrodynamic radius (annulus) model developed by us earlier for the effective viscosity of porous-particle suspensions.
Analytical description of a system of two interacting identical uniaxial ferromagnetic particles
Authors: Petrila Iulian , Stancu Alexandru
Published: August 2011

In this paper, we present an analytical method to study the magnetization processes of two magnetic particles with ferromagnetic or antiferromagnetic coupling by using a modified expression for the anisotropy free energy. By considering a system consisting of two uniaxial particles, coupled by a simple exchange interaction, we describe analytically: the particles orientations, switching points and hysteresis loops for different ferromagnetic or antiferromagnetic couplings and for different orientations of the applied field.
Frequency effects on the electron density and α-γ mode transition in atmospheric radio frequency discharges
Authors: Zhang Yuan-Tao , Cui Shao-Yan
Published: August 2011

In this paper, a one-dimensional model is explored to investigate the frequency effects on the characteristics of atmospheric radio frequency discharges at a given power. The simulation data and analytical results show that the improvement of electron density can be observed with better discharge stability by increasing excitation frequency in an appropriate range. Using the analytical equations deduced from the model, the mean electron density could be inferred by means of the measured parameters. The α-γ mode transition especially in high frequency discharges is also analytically discussed based on the theoretical equations.
Theoretical investigation of thermophysical properties in two-temperature argon-helium thermal plasma
Authors: Sharma Rohit , Singh Gurpreet , Singh Kuldip
Published: September 2011

The thermophysical properties of argon-helium thermal plasma have been studied in the temperature range from 5000 to 40 000 K at atmospheric pressure in local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions. Two cases of thermal plasma considered are (i) ground state plasma in which all the atoms and ions are assumed to be in the ground state and (ii) excited state plasma in which atoms and ions are distributed over various possible excited states. The influence of electronic excitation and non-equilibrium parameter θ = Te/Th on thermodynamic properties (composition, degree of ionization, Debye length, enthalpy, and total specific heat) and transport properties (electrical conductivity, electron thermal conductivity, and thermal diffusion ratio) have been studied. Within the framework of Chapman-Enskog method, the higher-order contributions to transport coefficient and their convergence are studied. The influence of different molar compositions of argon-helium plasma mixture on convergence of higher-orders is investigated. Furthermore, the effect of different definitions of Debye length has also been examined for electrical conductivity and it is observed that electrical conductivity with the definition of Debye length (in which only electrons participate in screening) is less than that of the another definition (in which both the electrons and ions participate in screening) and this deviation increases with electron temperature. Finally, the effect of lowering of ionization energy is examined on electron number density, Debye length, and higher-order contribution to electrical conductivity. It is observed that the lowering of the ionization energy affects the electron transport-properties and consequently their higher-order contributions depending upon the value of the non-equilibrium parameter θ.
Temperature-dependent growth shapes of Ni nanoclusters on NiAl(110)
Authors: Han Yong , Ünal Barış , Jing Dapeng , Thiel P. A. , Evans J. W.
Published: August 2011

Scanning tunneling microscopy studies reveal that two-dimensional nanoscale Ni islands formed by deposition of Ni on NiAl(110) between 200–400 K exhibit far-from-equilibrium growth shapes which change systematically with temperature. Island structure reflects the two types of adsorption sites available for Ni adatoms, and island shapes are controlled by the details of adatom diffusion along island edges accounting for numerous local configurations. The temperature dependence of the island shapes is captured and elucidated by kinetic Monte Carlo simulation of a realistic atomistic-level multisite lattice-gas model incorporating precise diffusion barriers. These barriers are obtained by utilizing density functional theory to probe energetics not just at adsorption sites but also at transition states for diffusion. This success demonstrates a capability for predictive atomistic-level modeling of nanocluster formation and shape selection in systems that have a high level of energetic and kinetic complexity.
Some aspects of the protein folding problem examined in one-dimensional systems
Authors: Ben-Naim Arieh
Published: August 2011

Some concepts, such as energy landscape, Gibbs energy landscape, and cooperativity, frequently used in the theory of protein folding, are examined exactly in one-dimensional systems. It is shown that much of the confusion that exists regarding these, and other concepts arise from the misinterpretation of Anfinsen's thermodynamic hypothesis.
A solid-state Marx generator driven Einzel lens chopper
Authors: Adachi T. , Arai T. , Leo K. W. , Takayama K. , Tokuchi A.
Published: September 2011

A new type of pulse chopper called an Einzel lens chopper is described. An Einzel lens placed immediately after an electron cyclotron resonance ion source is driven by high-voltage pulses generated by a newly developed solid-state Marx generator. A rectangular negative barrier pulse-voltage is controlled in time, and the barrier pulse is turned on only when a beam pulse is required. The results of successful experiments are reported herein.
Kinetic analysis of two dimensional metallic grating Cerenkov maser
Authors: Zhao Ding
Published: August 2011

The dispersion relation of two dimensional metallic grating Cerenkov maser has been given by using kinetic analysis, in which the influence of electron movement is directly considered without using an equivalent dielectric medium assumption. The effects of structural parameters and beam state on the interaction gain and synchronous frequency have also been investigated in detail by numerical calculations. To an illustrative case, the quantitative relations produced from varying the gap distance between electron beam and metallic grating, beam current, electron transverse to axial velocity ratio, and electron axial velocity spread have been obtained. The developed method can be used to predict the real interaction system performances.