bluuebunny/crossref_metadata_2025 huggingface dataset:
Does meeting standards affect charitable giving? An empirical study of New York metropolitan area charities
Authors: Chen Greg
Published: March 2009

Charitable donations constitute a significant revenue source for many nonprofit organizations. To help donors decide which nonprofits to support, watchdog organizations such as the Better Business Bureau (BBB) Wise Giving Alliance have developed standards to promote wise giving. The effectiveness of these guides in channeling limited resources to the best‐managed nonprofits is not widely studied. This research attempts to empirically investigate the effects of standards on public giving, controlling for factors that have documented effects on donations. Specifically, it regresses public support on the extent to which local nonprofits meet the standards of the Better Business Bureau Serving Metropolitan New York, Mid‐Hudson and Long Island Regions, controlling for organization size, board size, service category, government funding, fundraising expense, and giving price. The study found that BBB standards have a positive effect on giving behavior. Meeting BBB standards is associated with higher levels of public support. Participating in assessment programs and striving to meet the standards are recommended for nonprofits seeking to improve funding through charitable contributions. Further study that extends the search for the mechanism that links meeting standards to improved donations is recommended.
A CFL‐free explicit characteristic interior penalty scheme for linear advection‐reaction equations
Authors: Wang Kaixin , Wang Hong , Al‐Lawatia Mohamed
Published: March 2009

We develop a CFL‐free, explicit characteristic interior penalty scheme (CHIPS) for one‐dimensional first‐order advection‐reaction equations by combining a Eulerian‐Lagrangian approach with a discontinuous Galerkin framework. The CHIPS method retains the numerical advantages of the discontinuous Galerkin methods as well as characteristic methods. An optimal‐order error estimate in the L2 norm for the CHIPS method is derived and numerical experiments are presented to confirm the theoretical estimates. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Stable isotope studies in the Salitroso Lake Basin (southern Patagonia, Argentina): assessing diet of Late Holocene hunter‐gatherers
Authors: Tessone A. , Zangrando A. F. , Barrientos G. , Goñi R. , Panarello H. , Cagnoni M.
Published: March 2009

This work aims to present the carbon and nitrogen stable isotope data for human and environmental samples in order to discuss the dietary patterns of Late Holocene hunter‐gatherers from Salitroso Lake (southern Patagonia, Argentina) within the framework of ongoing research oriented to investigate the socio‐ecology of these populations. We present data for a sample of 24 human skeletons, 19 of which have been radiocarbon‐dated to between 2600 and 350 years BP. Faunal skeletal remains and modern plants are sampled in order to get a better understanding of the isotopic ecology at a regional level. The mean stable isotope values corresponding to these human samples are: δ13C (n = 24) = −19.05 ± 0.65‰, and δ15N (n = 11) = 11.77 ± 0.92‰. These results highlight the importance of terrestrial C3 ecosystems as the main source of dietary resources for these hunter‐gatherer populations. Finally, there is a comparison of stable isotopes of 13C and 15N on a supra‐regional scale to highlight the particularities of the samples presented here for the Late Holocene in Patagonia. Copyright © 2009 John Wiley & Sons, Ltd.
Diet, nutrition and femoral robusticity of hunter‐gatherers in southern Patagonia: experiences and perspectives
Authors: Suby J. A. , Guichón R. A.
Published: March 2009

Dietary reconstructions through stable isotope studies are one of the most prominent tools for analysing the impact of nutritional and subsistence strategy transitions in the health of past human populations. In the last few years, some palaeopathological studies have been developed related to dietary models proposed for southern Patagonia. In the present work we study the femoral diaphyseal robusticity as an indicator of physical activity and health of a sample of hunter‐gatherer individuals from southern Patagonia in relation to their diet, recorded by means of stable isotope values. We discuss the relationship between nutrition and the characteristics of bone structure, as well as the possible impact of pathologies as a source of variability in stable isotope values. Copyright © 2009 John Wiley & Sons, Ltd.
Photosynthetic pathways, spatial distribution, isotopic ecology, and implications for pre‐Hispanic human diets in central‐western Argentina
Authors: Llano C.
Published: March 2009

In a number of areas around the world researchers have begun to use the isotopic values of subsistence resources as a means of determining diets of human populations. The objective of the present study is to classify the plant species present at distinct altitudes in southern Mendoza Province, Argentina, considering photosynthetic pathways in order to determine their δ
13C isotopic signature. This will help to understand the relationships between diets and the isotopic values observed in archaeological human remains. Data compiled from various sources are used to establish the photosynthetic pathways and mean δ
13C values. The results indicate that C3 species are dominant at high‐altitude settings, and that the few identified C4 species were found primarily at lower altitudes. These results are intended to serve as a foundation for future isotopic studies designed to address relationships among species at different trophic levels. Copyright © 2009 John Wiley & Sons, Ltd.
Atypical hemolytic uremic syndrome responsive to steroids and intravenous immune globulin
Authors: Watt Tanya , Warshaw Barry , Katzenstein Howard M.
Published: March 2009

Atypical hemolytic uremic syndrome remains a challenge to diagnose and treat, with significant acute morbidity and risk for progression to end stage renal disease. Treatment strategies center on plasma exchange but do not necessarily affect the progression of disease. We report the case of a patient with atypical HUS resulting from a mutation in the complement pathway who responded to treatment with steroids and IVIG, therefore avoiding transfusion or plasma exchange. Pediatr Blood Cancer 2009;53:90–91. © 2009 Wiley‐Liss, Inc.
Massive ovarian oedema: An unusual abdominal mass in infancy
Authors: Moon Rebecca J. , Mears Alice , Kitteringham Lara J. , Gonda Peter , Kohler Janice A. , Davies Justin H.
Published: March 2009

We describe a 13‐month‐old female who presented with vaginal bleeding, breast and pubic hair development and an abdominal mass. She underwent emergency laparotomy and left‐sided salpingoopherectomy. Histological examination of the resected ovary revealed massive ovarian oedema, a rare non‐neoplastic enlargement of the ovary. Consideration of this diagnosis in patients with an abdominal mass and endocrine disturbance may allow conservative surgery and preservation of fertility. Pediatr Blood Cancer 2009;53:217–219. © 2009 Wiley‐Liss, Inc.
Risk of clinically relevant bleeding in warfarin‐treated patients—influence of SSRI treatment
Authors: Wallerstedt Susanna M , Gleerup Hanna , Sundström Anders , Stigendal Lennart , Ny Lars
Published: March 2009

Purpose

To investigate the risk of clinically relevant bleeding in warfarin‐treated patients with or without concomitant treatment with selective serotonin reuptake inhibitors (SSRIs).

Methods

A cohort study was performed in patients treated with warfarin due to atrial fibrillation. Exposed patients were defined as patients treated with SSRI at any time between January 1999 and September 2005 (n = 117). Unexposed patients without SSRI‐treatment were randomly selected and matched for age and sex (1:1). The primary endpoint was hospital admission due to bleeding during the same time period.

Results

Bleeding occurred in 17 exposed patients (totally 23 bleedings) and in two unexposed patients (totally two bleedings) (p = 0.0003). A total of 11 bleedings occurred during treatment with the combination of warfarin and SSRI, and 14 during treatment with warfarin only. The total incidences of bleedings per 1000 treatment years were 51.4 (25.7–92.0) and 23.9 (13.1–40.1), respectively, and the unadjusted incidence rate ratio (IRR) 2.15 (0.88–5.11). Cox regression analysis including first bleedings revealed an adjusted hazard ratio of 3.49 (1.37–8.91) for bleeding during treatment with a combination of SSRI and warfarin compared with treatment with warfarin only. Initiation of SSRI therapy was not associated with a change in dose of warfarin or with a change in international normalized ratio (INR) (p = 0.48 and p = 0.31, respectively).

Conclusion

Addition of SSRI to warfarin‐treated patients may be associated with an increased risk of clinically relevant bleeding. The effect seems not to be associated with a direct influence of SSRI on the anti‐coagulant activity of warfarin. Copyright © 2009 John Wiley & Sons, Ltd.
The human urinary proteome reveals high similarity between kidney aging and chronic kidney disease
Authors: Zürbig Petra , Decramer Stéphane , Dakna Mohammed , Jantos Justyna , Good David M. , Coon Joshua J. , Bandin Flavio , Mischak Harald , Bascands Jean‐Loup , Schanstra Joost P.
Published: March 2009

Aging induces morphological changes of the kidney and reduces renal function. We analyzed the low molecular weight urinary proteome of 324 healthy individuals from 2–73 years of age to gain insight on human renal aging. We observed age‐related modification of secretion of 325 out of over 5000 urinary peptides. The majority of these changes were associated with renal development before and during puberty, while 49 peptides were related to aging in adults. We therefore focussed the remainder of the study on these 49 peptides. The majority of these 49 peptides were also markers of chronic kidney disease, suggesting high similarity between aging and chronic kidney disease. Blinded evaluation of samples from healthy volunteers and diabetic nephropathy patients confirmed both the correlation of biomarkers with aging and with renal disease. Identification of a number of these aging‐related peptides led us to hypothesize that reduced proteolytic activity is involved in human renal aging. Finally, among the 324 supposedly healthy individuals, some had urinary aging‐related peptide excretion patterns typical of an individual significantly older than their actual age. In conclusion, these aging‐related biomarkers may allow noninvasive detection of renal lesions in healthy persons and show high resemblance between human aging and chronic kidney disease. This similarity has to be taken into account when searching for biomarkers of renal disease.
Control—the Striga conundrum
Authors: Hearne Sarah J
Published: March 2009

There is a wide range of existing and potential control options for Striga. This paper describes and discusses many of the control options, with a focus on technology limitations, adoption limitations (real or potential) and, in the case of novel technologies, development limitations. The paper addresses the question as to why, after many years of research, control method testing, piloting and technology dissemination, the wide‐scale effective control of Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze is so elusive. Limitations, including variable technology reliability, poor access to control technology, costs (monetary, labour, skills) associated with control technology, limited practicality of methods and poor information, all hamper the adoption and impact of existing control methods. Some of the same issues may impact upon novel control technologies, and this needs careful consideration. Additional issues surround other potential technologies, especially so in the case of transgenic approaches. Suggestions are made as to how the impasse of effective Striga control can be overcome. More effective use of integrated control approaches, improved crop germplasm phenotyping, enhanced understanding of the host/non‐host—parasite interaction and better integration and communication among the parasitic plant research, development and extension community are among the suggestions made. Copyright © 2009 Society of Chemical Industry
Study on dephasing dynamics of Exciton Fine Structure in GaN
Authors: Ishiguro T. , Toda Y. , Adachi S. , Chichibu S. F.
Published: March 2009

We report on the dephasing dynamics of exciton fine structure (EFS) in a free standing GaN. The EFS was observed and studied by utilizing a four‐wave‐mixing (FWM) spectroscopy. In the cleavage plane of wurtzite GaN, we can excite the B‐exciton fine structure, whose z ‐polarized state is energetically well separated from the other in‐plane polarized exciton states. Due to the large spin exchange interaction in GaN, an energy shift of in‐plane polarized fine structure was also observed.

Since the each component of EFS is highly polarized, the polarization‐dependent FWM successfully resolves their dephasing dynamics. The results show a significant difference in the dephasing time between EFS, suggesting that anisotropic exchange interaction is effective as reported in our previous work using a GaN film on a ‐plane sapphire (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MOVPE growth of high‐quality Al0.1Ga0.9N on Si(111) substrates for UV‐LEDs
Authors: Saengkaew Phannee , Dadgar Armin , Blaesing Juergen , Bastek Barbara , Bertram Frank , Reiher Fabian , Hums Christoph , Noltemeyer Martin , Hempel Thomas , Veit Peter , Christen Juergen , Krost Alois
Published: March 2009

We have investigated the growth parameters of AlN seeding and buffer layers to improve the crystalline quality of Al0.1Ga0.9N on Si (111) substrates. We present the dependence of AlN seeding layer growth conditions using X‐ray diffraction (XRD) and atomic force microscopy measurements to achieve high‐quality Al0.1Ga0.9N growth. To further improve the Al0.1Ga0.9N quality, AlN‐based superlattices (SLs) with different growth temperatures were introduced as buffer layers. With the optimized growth parameters of AlN seeding layers and AlN‐based SLs, best FWHMs of XRD ω‐scans around the (0002) reflection of 540 arcsec and 1400 arcsec for the (10‐10) reflection were achieved for a ∼1‐μm‐thick Al0.1Ga0.9N layer. FE‐SEM and TEM measurements show that the optimized high temperature‐AlN/low temperature‐AlN SL buffer layers were able to act as dislocation filters for high‐quality Al0.1Ga0.9N growth. In addition, Cathodoluminecence measurements showed near‐bandgap luminescence peaks of Al0.1Ga0.9N with high intensity and narrow linewidth. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TEM characterization of M ‐plane InN grown on (100) LiAlO2 substrate by RF‐MBE
Authors: Nozawa Hirokazu , Takagi Yusuke , Harui Satoshi , Muto Daisuke , Yamaguchi Tomohiro , Araki Tsutomu , Nanishi Yasushi
Published: March 2009

In this study, we characterized the microstructure of M ‐plane InN using transmission electron microscopy (TEM). The M ‐plane InN was grown on a (100) LiAlO2 substrate using radio‐frequency plasma‐assisted molecular beam epitaxy (RF‐MBE). We determined the epitaxial relationships of the M ‐plane InN and LiAlO2 using selected area electron diffraction (SAED). The epitaxial relationships were exactly the same as the M ‐plane GaN grown on the same substrate. Also, the M ‐plane InN was grown on the (100) LiAlO2 despite the high lattice mismatches between M ‐plane InN and LiAlO2. We observed a high density of stacking faults parallel to (0001)InN. The density was estimated about 1.8×106 cm–1, which was one order of magnitude higher than that of non‐polar GaN. The correlation between threading dislocations and stacking faults is investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxy of m ‐plane ZnO on (112) LaAlO3 substrate
Authors: Ho Yen‐Teng , Wang Wei‐Lin , Peng Chun‐Yen , Chen Wei‐Chun , Liang Mei‐Hui , Tian Jr.‐Sheng , Chang Li
Published: March 2009

Heteroepitaxial growth of non‐polar m ‐plane (10$ \bar 1 $0) ZnO has been demonstrated on (112) LaAlO3 single crystal substrates using the pulsed laser deposition method. X‐ray diffraction, reflection high energy electron diffraction, and cross‐sectional transmission electron microscopy with selected‐area diffraction, have been used to characterize the structural properties of deposited ZnO films. The epitaxial relationship between ZnO and LAO is shown to be (10$ \bar 1 $0)ZnO ∥ (112)LAO, (11$ \bar 2 $0)ZnO ∥ ($ \bar 1 $$ \bar 1 $1)LAO and [0001]ZnO ∥ [$ \bar 1 $10]LAO. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flow design of guiding device for downstream fish migration
Authors: Lundström T. Staffan , Hellström J. Gunnar I. , Lindmark Elianne M.
Published: March 2009

Downstream migrating smolt must be guided around hydropower plants to avoid fish mortality due to the turbines. In Piteå River, which is already regulated, open spillways serve this purpose but few fish find this route. Hence, action must be taken to enhance downstream fish migration. One way to attract the fish to the spillways is to direct the surface flow towards them by means of a guiding device. The hydrodynamic design of one such device is outlined using numerical calculations of the flow upstream the spillways and by the assumption that the fish moves near the surface of the water. A number of geometries are evaluated by starting from a straight impermeable barrier that extends 2 m down from the water surface and stretches over a part of the river. A major result is that it is possible to redirect the surface water towards the spillways at very low spilling rates which means high energy efficiency. Another finding was that the device should stretch over a large part of the river. For optimal functionality, the spilling should match the guiding device geometry. High spilling implies that the guiding has a low impact while for low spilling the geometry is crucial for successful downstream migration. Copyright © 2009 John Wiley & Sons, Ltd.
Design of Synthetic Polymer Nanoparticles that Capture and Neutralize a Toxic Peptide
Authors: Hoshino Yu , Urakami Takeo , Kodama Takashi , Koide Hiroyuki , Oku Naoto , Okahata Yoshio , Shea Kenneth J.
Published: March 2009

Designed polymer nanoparticles (NPs) capable of binding and neutralizing a biomacromolecular toxin are prepared. A library of copolymer NPs is synthesized from combinations of functional monomers. The binding capacity and affinity of the NPs are individually analyzed. NPs with optimized composition are capable of neutralizing the toxin even in a complex biological milieu. It is anticipated that this strategy will be a starting point for the design of synthetic alternatives to antibodies.
Teaching evolution: Narratives with a view from three southern biology teachers in the USA
Authors: Goldston M. Jenice “Dee” , Kyzer Peggy
Published: March 2009

This case study explored sociocultural forces that influenced three 10th grade public high school biology teachers' instructional goals, instructional acts, and identity narratives related to the teaching of evolution. Primary data included field observations of classroom instruction and teacher interviews. Secondary data included informal conversations with students, interviews with department chairs, and interviews with a Southern minister. Data were coded and analyzed resulting in categories and themes which provided insights into the sociocultural influences that gave shape to the teaching of evolution for three teachers in this southeastern state. Findings included: (a) changes in teaching identities as the teachers sought legitimacy for teaching evolution through dependency on the textbook as the authoritative knowledge, (b) socioculturally embedded lived experiences and the perceived teaching identity of each teacher that created idiosyncratic positionings related to decisions about teaching evolution, and (c) the complicatory influence of the state standards, the graduation exit examination, and teacher autonomy on teachers' decisions related to the teaching of evolution. This study revealed practical relationships between what actual practices occur when teachers include or exclude evolution within the curriculum and the liabilities and benefits of teacher autonomy related to controversial topics such as evolutionary theory. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 762–790, 2009
The OGLE-III catalog of variable stars: First results
Authors: Soszyński Igor
Published: March 2009

The third phase of the Optical Gravitational Lensing Experiment (OGLE-III) has been conducted since 2001 and regularly monitors the brightness of about 200 million stars. The OGLE-III fields cover both Magellanic Clouds and a large area in the Galactic bulge and disk. Here we describe the first parts of the OGLE-III Catalog of Variable Stars which is being prepared on the basis of these data. We present the principles of the catalog and methods used to select variable stars. We expect that the whole catalog will contain at least one million variable stars of all types. The catalog includes the list of variable sources along with their basic parameters, high precision multi-epoch I and V-band photometry and accurate astrometry. All objects are classified and cross-identified with previously published catalogs. We also carry out a preliminary statistical analysis of these huge samples of variable stars.
The binarity of the Clouds and the formation of the Magellanic Stream
Authors: Besla Gurtina , Kallivayalil Nitya , Hernquist Lars , van der Marel Roeland P. , Cox T. J. , Robertson Brant , Alcock Charles
Published: March 2009

The HST proper motion (PM) measurements of the Clouds have severe implications for their interaction history with the Milky Way (MW) and with each other. The Clouds are likely on their first passage about the MW and the SMC's orbit about the LMC is better described as quasi-periodic rather than circular. Binary L/SMC orbits that satisfy observational constraints on their mutual interaction history (e.g., the formation of the Magellanic Bridge during a collision between the Clouds ~300 Myr ago) can be located within 1σ of the mean PMs. However, these binary orbits are not co-located with the Magellanic Stream (MS) when projected on the plane of the sky and the line-of-sight velocity gradient along the LMC's orbit is significantly steeper than that along the MS. These combined results ultimately rule out a purely tidal origin for the MS: tides are ineffective without multiple pericentric passages and can neither decrease the velocity gradient nor explain the offset stream in a polar orbit configuration. Alternatively, ram pressure stripping of an extended gaseous disk may naturally explain the deviation. The offset also suggests that observations of the little-explored region between RA 21h and 23h are crucial for characterizing the full extent of the MS.
Models for the dynamical evolution of the Magellanic System
Authors: Bekki Kenji
Published: March 2009

I discuss the following five selected topics on formation and evolution of the LMC and the SMC based on fully self-consistent chemodynamical simulations of the Magellanic Clouds (MCs): (1) formation of bifurcated gaseous structures and young stars in the Magellanic bridge (MB), (2) formation of the Magellanic stream (MS) due to the tidal interaction between the LMC, the SMC, and the Galaxy within the last 2 Gyrs, (3) origin of the observed kinematical differences between H i gas and stars in the SMC, (4) formation of stellar structures dependent on their ages and metallicities in the LMC, and (5) a new common halo model explaining both the latest HST ACS observations on the proper motions of the LMC and the SMC and the presence of the MS in the Galactic halo. I focus exclusively on the latest developments in numerical simulations on formation and evolution of the Magellanic system.
The many streams of the Magellanic Stream
Authors: Stanimirović Snežana , Hoffman Samantha , Heiles Carl , Douglas Kevin A. , Putman Mary , Peek Joshua E. G.
Published: March 2009

As a part of the ongoing H i survey by the consortium for Galactic studies with the Arecibo L-band Feed Array (GALFA-HI), we have recently imaged the tip of the MS and found several long filamentary structures. This demonstrates that the northern portion of the MS, which has been interacting with the Galactic halo for a long time, is more extended than previously thought and in the form of highly organized H i structures. The observed filaments, and especially the kinematic dichotomy of H i clouds observed for the first time, agree with predictions by the Connors, Kawata & Gibson (2006) tidal model. However, specific time-stamps in the history of the Magellanic System are required to explain these phenomena. The 20-degree long filaments are accompanied by a large population of small H i clouds. We investigate the observed properties of these clouds and explore various instabilities that affect a warm tail of gas trailing through the Galactic halo. Interestingly, if the observed H i structure is mainly due to thermal instability, then the tip of the MS is at a distance of ~70 kpc.
Tracing the cold molecular gas reservoir through dust emission in the SMC
Authors: Bot Caroline , Rubio Mónica , Boulanger François , Albrecht Marcus , Bertoldi Frank , Bolatto Alberto D. , Leroy Adam K.
Published: March 2009

The amount of molecular gas is a key for understanding the future star formation in a galaxy. However, this quantity is difficult to infer as the cold H2 is almost impossible to observe and, especially at low metallicities, CO only traces part of the clouds, keeping large envelopes of H2 hidden from observations. In this context, millimeter dust emission tracing the cold and dense regions can be used as a tracer to unveil the total molecular gas masses. I present studies of a sample of giant molecular clouds in the Small Magellanic Cloud. These clouds have been observed in the millimeter and sub-millimeter continuum of dust emission: with SIMBA/SEST at 1.2 mm and the new LABOCA bolometer on APEX at 870 μm. Combining these with radio data for each cloud, the spectral energy distribution of dust emission are obtained and gas masses are inferred. The molecular cloud masses are found to be systematically larger than the virial masses deduced from CO emission. Therefore, the molecular gas mass in the SMC has been underestimated by CO observations, even through the dynamical masses. This result confirms what was previously observed by Bot et al. (2007). We discuss possible interpretations of the mass discrepancy observed: in the giant molecular clouds of the SMC, part of cloud's support against gravity could be given by a magnetic field. Alternatively, the inclusion of surface terms in the virial theorem for turbulent clouds could reproduce the observed results and the giant molecular clouds could be transient structures.
Stellar evolution models at the Magellanic Cloud metallicities
Authors: Hirschi Raphael , Ekström Sylvia , Georgy Cyril , Meynet Georges , Maeder André
Published: March 2009

The Magellanic Clouds are great laboratories to study the evolution of stars at two metallicities lower than solar. They provide excellent testbeds for stellar evolution theory and in particular for the impact of metallicity on stellar evolution. It is important to test stellar evolution models at metallicities lower than solar in order to use the models to predict the evolution and properties of the first stars. In these proceedings, after recalling the effects of metallicity, we present stellar evolution models including the effects of rotation at the Magellanic Clouds metallicities. We then compare the models to various observations (ratios of sub-groups of massive stars and supernovae, nitrogen surface enrichment and gamma-ray bursts) and show that the models including the effects of rotation reproduce most of the observational constraints.
Thermally-pulsing asymptotic giant branch stars in the Magellanic Clouds
Authors: Marigo Paola , Girardi Léo , Bressan Alessandro , Groenewegen Martin A. T. , Aringer Bernhard , Silva Laura , Granato Gian Luigi
Published: March 2009

We present the latest results of a theoretical project aimed at investigating the properties of thermally-pulsing asymptotic giant branch (TP-AGB) stars in different host systems. For this purpose, we have recently calculated calibrated synthetic TP-AGB tracks — covering a wide range of metallicities (0.0001 ≤ Z ≤ 0.03) up to the complete ejection of the envelope by stellar winds (Marigo & Girardi 2007) — and used them to generate new sets of stellar isochrones (Marigo et al. 2008). The latter are converted to about 25 different photometric systems, including the mid-infrared filters of Spitzer and AKARI as the effect of circumstellar dust from AGB stars is taken into account. First comparisons with AGB data in the MC field and stellar clusters are discussed.
On the self-consistent physical parameters of LMC intermediate-age clusters
Authors: Kerber Leandro O. , Santiago Basílio X.
Published: March 2009

The LMC clusters with similar ages to the Milky Way open clusters are in general more metal-poor and more populous than the latter, being located close enough to allow their stellar content to be well resolved. Therefore, they are unique templates of simple stellar population (SSP), being crucial to calibrate models describing the integral light as well as to test the stellar evolution theory. With this in mind we analyzed HST/WFPC2 (V, B − V) colour-magnitude diagrams (CMDs) of 15 populous LMC clusters with ages between ~0.3 Gyr and ~4 Gyr using different stellar evolutionary models. Following the approach described by Kerber, Santiago & Brocato (2007), we determined accurate and self-consistent physical parameters (age, metallicity, distance modulus and reddening) for each cluster by comparing the observed CMDs with synthetic ones generated using isochrones from the PEL and BaSTI libraries. These determinations were made by means of simultaneous statistical comparison of the main-sequence fiducial line and the red clump position, offering objective and robust criteria to select the best models. We compared these results with the ones obtained by Kerber, Santiago & Brocato (2007) using the Padova isochrones. This revealed that there are significant trends in the physical parameters due to the choice of stellar evolutionary model and treatment of convective core overshooting. In general, models that incorporate overshooting presented more reliable results than those that do not. Furthermore, the Padova models fitted better the data than the PEL and BaSTI models. Comparisons with the results found in the literature demonstrated that our derived metallicities are in good agreement with the ones from the spectroscopy of red giants. We also confirmed that, independent of the adopted stellar evolutionary library, the recovered 3D distribution for these clusters is consistent with a thick disk roughly aligned with the LMC disk as defined by field stars. Finally, we also provide new estimates of distance modulus to the LMC center, that are marginally consistent with the canonical value of 18.50 mag.
A study of AGB stars in LMC clusters
Authors: Lebzelter Thomas , Lederer Michael T. , Cristallo Sergio , Straniero Oscar , Hinkle Kenneth H.
Published: March 2009

LMC clusters offer an outstanding opportunity to investigate the late stages of stellar evolution of stars in the mass range between 1.5 and 2 M⊙. In this presentation we will focus on our results on mixing events during the evolution along the Asymptotic Giant Branch (AGB). Surface abundances have been determined for a number of cluster AGB stars from high resolution near infrared spectra. We show for the first time the evolution of C/O and 12C/13C ratios along a cluster AGB. The change of both quantities due to dredge up events is compared with model predictions. Our results indicate the late occurrence of a moderate extra-mixing in some cases.
The production of dust in the Magellanic Clouds
Authors: Sloan G. C.
Published: March 2009

The sensitivity of the Infrared Spectrograph on the Spitzer Space Telescope has enabled detailed surveys of mass-losing stars in the Large and Small Magellanic Clouds. Comparisons of samples from these galaxies and the Milky Way reveal how the dust produced by evolved stars depends on the metallicity of the host environment. Oxygen-rich stars show several trends with metallicity. In more metal-poor environments, fewer of them show dust excesses, the circumstellar SiO absorption grows weaker, the quantity of silicate dust decreases, and alumina dust grows rare. As carbon stars grow more metal-poor, the amount of circumstellar acetylene gas increases, while the amount of trace dust elements like SiC and MgS decreases. However, there is little dependence on metallicity in the amount of amorphous carbon dust produced by carbon stars, because they produce the carbon needed to make dust themselves. As galaxies grow more metal-poor, the composition of the dust they produce should grow more carbon rich.
High-exitation nebulae around Magellanic Wolf-Rayet stars
Authors: Pakull Manfred W.
Published: March 2009

The SMC harbours a class of hot nitrogen-sequence Wolf-Rayet stars (WNE) that display only relatively weak broad Heiiλ4686 emission indicative of their low mass-loss rates and which are therefore hard to detect. However, such stars are possible emitters of strong He+Lyman continua which in turn could ionize observable Heiiiregions, i.e. highly excited Hiiregions emitting nebular Heiiλ4686 emission. We here report the discovery of a second Heiiiregion in the SMC within OB association NGC 249 within which the weak-lined WN star SMC WR10 is embedded. SMC WR10 is of special importance since it is a single star showing the presence of atmospheric hydrogen. While analysing the spectrum in the framework of two popular, independent WR atmosphere models we found strongly discrepant predictions (by 1 dex) of the He+continuum for the same input parameters. A second interesting aspect of the work reported here concerns the beautiful MCELS images which clearly reveal a class of strongly Oiiiλ5007 emitting (blue-coded) nebulae. Not unexpectedly, most of the “blue” nebulae are known Wolf-Rayet bubbles, but new bubbles around a few WRs are also detected. Moreover, we report the existence of blue nebulae without associated known WRs and discuss the possibility that they reveal weak-wind WR stars with very faint stellar Heiiλ4686 emission. Alternatively, such nebulae might hint at the hitherto missing population of relatively low-mass, hot He stars predicted by massive binary evolution calculations. Such a binary system is probably responsible for the ionization of the unique Heiiλ4686-emitting nebula N 44C.
Magnetic phase transition for three-dimensional Heisenberg weak random anisotropy model: Monte Carlo study
Authors: Nguyen Ha M. , Hsiao Pai-Yi
Published: March 2009

Magnetic phase transition (MPT) to magnetic quasi-long-range order (QLRO) phase in a three-dimensional Heisenberg weak (D/J=4) random anisotropy (RA) model is investigated by Monte Carlo simulation. The isotropic and cubic distributions of RA axes are considered for simple-cubic-lattice systems. Finite-size scaling analysis shows that the critical couplings for the former and latter are Kc=0.704 35(2) and Kc=0.709 98(4), respectively. While the critical exponent 1/ν=1.408 24(0) is the same for both cases. A second-order MPT to the QLRO phase is therefore evidenced to be possible in favor with the existence of the QLRO predicted by recent functional renormalization group theories.
Effect of ion-beam etching damage in Fe–Co tapered main pole
Authors: Ohsawa Yuichi , Yamakawa Kiyoshi , Muraoka Hiroaki
Published: March 2009

Effect of ion-beam etching damage in Fe–Co films was estimated and magnetic calculation of the planar head using tapered main pole (MP) including the etching damage was performed. The etching test on the Fe–Co films, whose thickness corresponds to half of the trackwidth for several Tbits/in.2, showed decrease in saturation magnetic flux density (Bs) and increase in coercivity with a 250 eV ion beam. The magnetic calculation showed relatively large decrease in head field and head field gradient as Bs of the damaged region decreases from 2.4 T. Damage control in the MP fabrication is one of the important issues for Tbits/in.2-era write heads.
PLD-fabricated anisotropic Nd–Fe–B thick films with Ga additive
Authors: Nakano M. , Tsutsumi S. , Yanai T. , Yamashita F. , Fukunaga H.
Published: March 2009

In this report, an evaluation on magnetic properties of pulsed laser deposition (PLD)-made anisotropic films with Ga additive was carried out. Coercivity, remanence, and (BH)max values of a film prepared from a Nd2.6Fe14B including Ga target were approximately 850 kA/m, 0.95 T, and 150 kJ/m3, respectively. These magnetic properties were superior compared with those for the anisotropic PLD-made Nd–Fe–B films without additives. The peak intensities of x-ray diffraction patterns corresponding to c-planes such as (004), (006), and (008) of the film with Ga additive were stronger than those of the additive-free film.
Mechanism of microwave assisted magnetic switching
Authors: Igarashi Masukazu , Suzuki Yoshio , Miyamoto Harukazu , Maruyama Youji , Shiroishi Yoshihiro
Published: March 2009

The characteristic of microwave assisted switching for an isolated grain was investigated using the Landau–Lifshitz–Gilbert simulation. It was found that anticlockwise and clockwise polarized fields assist magnetization to switch and to reswitch, respectively. Using larger linear polarized field, sufficient switching is not obtained. It was confirmed the magnetic resonance effect on the reduction in the switching field. It was also found that a large assist effect and a narrowing transition effect were achieved in exchange coupled subgrains.
Electrical properties and deep traps spectra in undoped and Si-doped m-plane GaN films
Authors: Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Markov A. V. , Yugova T. G. , Petrova E. A. , Amano H. , Kawashima T. , Scherbatchev K. D. , Bublik V. T.
Published: March 2009

Structural and electrical properties of nonpolar m-GaN films grown on m-SiC using standard metalorganic chemical vapor deposition (MOCVD) and two versions of sidewall epitaxial lateral overgrowth were studied. It is shown that lateral overgrowth allows one to dramatically reduce the dislocation density from over 109 cm−2 to ∼107 cm−2. In good correlation with that we observed a strong reduction in the density of electron traps Ec−0.25 eV and Ec−0.6 eV from over 1015 cm−3 to ∼1014 cm−3, respectively, in MOCVD m-GaN and in laterally overgrown m-GaN. Preliminary studies of the effects of changing the V/III ratio and of Si doping were performed. The MOCVD m-GaN films grown with high V/III ratio of 1000 were semi-insulating, with the Fermi level pinned near the 0.6 eV traps. Decreasing the V/III value to 250 shifted the Fermi level upward, close to the level of the 0.25 eV traps. Si doping in laterally overgrown samples strongly suppressed the formation of major electron traps but enhanced the formation of hole traps near Ev+0.9 eV. We also report on electrical properties of the GaN interface with the AlN buffer used to facilitate good quality growth on SiC. These properties are dominated by a high concentration of 0.15 eV traps.
Large anisotropic magnetoresistance of ruthenium-based Heusler alloys
Authors: Mizusaki S. , Ohnishi T. , Douzono A. , Nagata Y. , Ozawa T. C. , Samata H. , Noro Y.
Published: March 2009

Anomalous magnetic behavior was found in the polycrystalline Heusler alloy system Ru2Mn1−xFexGe. Samples of x=0 and 1.0 show no magnetoresistance (MR); however, the anisotropic MR effect is observed for x=0.5 (MR ratios of −4% and +2% are observed under parallel and perpendicular configurations of applied field and applied current, respectively). Moreover, magnetic measurement revealed that the sample of x=0 is antiferromagnetic, whereas the samples of x=0.5 and 1.0 are ferromagnetic with Curie temperatures of 270 and 490 K, respectively. The saturation magnetization and coercivity at 5 K are 3.1μB/f.u. and negligibly small for x=1.0 and 1.8μB/f.u. and 0.1 T for x=0.5, respectively. The MR effect is explained by a model in which antiferromagnetic and ferromagnetic domains coexist.
Modeling of field emission from nanowires
Authors: Marinov T. M. , Hariharan S. I.
Published: March 2009

This work presents a procedure for calculating field emission from conducting nanofibers based on an electrostatic continuum model. A perfectly conducting nanofiber with finite length in the presence of a static electric field is considered. An analytic expression is obtained for the resultant electrostatic potential by employing the slender body approximation. The total external potential is used in conjunction with the one-dimensional WKB approximation to estimate the tunneling probability of the electrons in the fiber due the total external field. Unlike the standard Fowler–Nordheim method, the current density of the field emission is obtained by using quantum wire density of states for room temperature. Results are compared with results from the Fowler–Nordheim method for Ni nanofibers as well as with recent experimental results.
Single-mode phonon transmission in symmetry-broken carbon nanotubes: Role of phonon symmetries
Authors: Wang Jian , Wang Jian-Sheng
Published: March 2009

We investigate the single-mode phonon transmission in symmetry-broken carbon nanotubes with the Stone-Wales defect using a mode-matching method. To gain an insight into the features of the transmission, the symmetry properties of phonons are analyzed within the line group symmetry theory for single-walled carbon nanotubes. Our results show that the transmission for acoustic phonons with low group velocity is heavily suppressed, and the long-wave optical phonons near the Γ point are strongly scattered by defects. We clarify that this reduction in transmission for phonons with small group velocity is a universal behavior resulting from the broken translational invariance. Furthermore, fine structures of dips in the transmission are observed for some phonon modes, depending on the unmatched symmetry operations between the specific phonon mode and the defect. Our findings reveal that heat generation in experiments for the defective nanotubes may be contributed largely from the phonons with low group velocity because of their low transmissions. We propose the mode-dependent transmission for the single-mode phonon be utilized to identify the different phonon modes through the features for the fine structures of the transmission in experiments.
Crystallinity dependence of resistance switching in La0.7Ca0.3MnO3 films grown by pulsed laser deposition
Authors: Shang D. S. , Chen L. D. , Wang Q. , Yu W. D. , Li X. M. , Sun J. R. , Shen B. G.
Published: March 2009

Resistance switching property induced by pulsed electric-field in metal-oxide-metal sandwiches attracted much interest due to its potential application in nonvolatile memory devices. In this paper, the influence of the crystallinity of La0.7Ca0.3MnO3 (LCMO) film on the resistance switching of Ag-LCMO-Pt sandwiches has been investigated. LCMO films were grown on Pt/Ti/SiO2/Si substrates using pulsed laser deposition technique at different substrate temperatures. The crystallinity of LCMO films were characterized by x-ray diffraction, atomic force microscopy, transmission electron microscopy, and x-ray photoelectron microscopy. The results show that the crystallinity of LCMO films changed from the amorphous phase to (200) oriented nanocrystalline grains by varying the deposition temperature from 500 to 700 °C. The amorphous LCMO films were crystallized through rapid thermal annealing process under oxygen atmosphere. The coexistence of crystalline grains and grain boundaries results in the inhomogenous conductivity in LCMO films. Current-voltage characteristics and pulsed bias measurements indicate that nonvolatile resistance switching only takes place in the crystallized LCMO films and the resistance change ratio depends on the grain size of LCMO films. These results were described as the electric field induced oxygen vacancy annihilation/generation combined with the change of electron/hole trap density at the local interface between the Ag electrode and the crystalline grains in the LCMO film.
Electromechanical coupling coefficient k31eff for arbitrary aspect ratio resonators made of [001] and [011] poled (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals
Authors: Chen Chuanwen , Zhang Rui , Wang Zhu , Cao Wenwu
Published: March 2009

The dependence of k31eff on the aspect ratio G=l1/l2 has been calculated for resonators made of [001] poled 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (PMN-0.33PT) and [011] poled 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 (PMN-0.29PT). Based on the derived unified formula, the lateral electromechanical energy conversion efficiency |k31eff|2 decreases with G for [001] poled PMN-0.33PT but increases with G for [011] poled PMN-0.29PT.
Stimulated Brillouin backscattering and ion acoustic wave secondary instability
Authors: Cohen B. I. , Williams E. A. , Berger R. L. , Pesme D. , Riconda C.
Published: March 2009

A study of the secondary instability of a finite-amplitude ion acoustic wave (IAW) affecting the saturation of stimulated Brillouin backscattering (SBS) of laser light in a plasma is presented. The secondary instability of the SBS IAW provides a nonlinear dissipation mechanism for the SBS IAW and can reduce the SBS reflectivity. To better understand the physics of the secondary instability and SBS, particle-in-cell kinetic simulations, analysis of dispersion relations, and integration of coupled mode equations have been undertaken and compared. Among the effects examined are the influences on the secondary instability of the frequency of the primary IAW, the second-harmonic IAW, and ion trapping in the primary SBS IAW which affects Landau damping and the IAW frequency.
Electromigration effect on pancake type void propagation near the interface of bulk solder and intermetallic compound
Authors: Yao Yao , Keer Leon M. , Fine Morris E.
Published: March 2009

Due to the reduction in the size of electronic devices and solder interconnects, their current densities are rapidly increasing and the effect of electromigration becomes more critical to interconnect failure. Traditional methods are not sufficient to determine the failure mechanisms of solder interconnects under such high current densities. An approach to predict the electromigration effect upon interconnect failure including void propagation is timely and useful to the electronics industry. The stress gradient in a 95.5Sn-4Ag-0.5Cu eutectic solder with a void defect is analyzed numerically to determine the electromigration and stress migration forces. A kinetic mass diffusion model is developed to predict void width and propagation speed near the interface between the intermetallic compound and bulk solder caused by electromigration. A three-dimensional finite element analysis has been performed to analyze the current crowding effect in the interconnect. The proposed kinetic model gives a reasonable prediction for the void width and propagation velocity as compared with experimental results.
Square-well fluid modelling of protein liquid-vapor coexistence
Authors: Duda Yurko
Published: March 2009

The liquid-vapor phase diagrams for square-well fluid with extremely short attractive well, λ=1.05 and 1.1, are obtained by means of canonical Monte Carlo simulations. These new results show that the coexistence curves obey the law of corresponding states in the similar form as several proteins do. Besides, the critical packing fraction of γ-crystalline obtained experimentally is surprisingly close to the critical value of the model fluid with λ=1.1. Thus, we demonstrate that the phase behavior of protein solutions may be modeled without taking into account an implicit anisotropic patchy character of the interprotein interaction.