bluuebunny/crossref_metadata_2025 huggingface dataset:
Academic self-efficacy: from educational theory to instructional practice
Authors: Artino Jr. Anthony R.
Published: April 2012

Self-efficacy is a personal belief in one’s capability to organize and execute
courses of action required to attain designated types of performances. Often described
as task-specific self-confidence, self-efficacy has been a key component in theories of
motivation and learning in varied contexts. Furthermore, over the last 34 years,
educational researchers from diverse fields of inquiry have used the notion of
self-efficacy to predict and explain a wide range of human functioning, from athletic
skill to academic achievement. This article is not a systematic review of the empirical
research on self-efficacy; instead, its purpose is to describe the nature and structure
of self-efficacy and provide a brief overview of several instructional implications for
medical education. In doing so, this article is meant to encourage medical educators to
consider and explicitly address their students’ academic self-efficacy beliefs in an
effort to provide more engaging and effective instruction.
Institutional Impact and Agricultural Change in Russia
Authors: Wegren Stephen K.
Published: April 2012

Set within the context of New Institutionalism, this article analyzes the impact of institutional change on Russian agriculture. Institutions are important because they create opportunity and incentives. The market-based institutional framework introduced in the 1990s acted as an independent variable that facilitated growth in entrepreneurial income and an increase in rural stratification. Further, institutions contributed to land expansion by a stratum of upper income households. As a dependent variable, indigenous factors influence the economic outcomes that flow from new institutions with a twofold effect: regional variance is significant for entrepreneurial income and land expansion; and some households experienced much higher entrepreneurial income and land expansion.
TGF‐β control of stem cell differentiation genes
Authors: Massagué Joan , Xi Qiaoran
Published: April 2012

The canonical TGF‐β/Smad signaling pathway was delineated in the mid 90s and enriched over the past decade with many findings about its specificity, regulation, networking, and malfunctions in disease. However, a growing understanding of the chromatin status of a critical class of TGF‐β target genes – the genes controlling differentiation of embryonic stem cells – recently prompted a reexamination of this pathway and its critical role in the regulation of stem cell differentiation. The new findings reveal master regulators of the pluripotent state set the stage for Smad‐mediated activation of master regulators of the next differentiation stage. Furthermore, a novel branch of the TGF‐β/Smad pathway has been identified in which a chromatin‐reading Smad complex makes the master differentiation genes accessible to canonical Smad complexes for transcriptional activation. These findings provide exciting new insights into the global role of TGF‐β signaling in the regulators of stem cell fate.
Phosphoproteomics of Arabidopsis chloroplasts reveals involvement of the STN7 kinase in phosphorylation of nucleoid protein pTAC16
Authors: Ingelsson Björn , Vener Alexander V.
Published: April 2012

RPOC2
,
RPOB
,
pTAC3
,
emb2746
,
RPOC1
,
pTAC2
,
pTAC12
,
pTAC16
,
pTAC5
,
pTAC14
,
RPOA
,
pTAC13
,
pTAC15
and
pTAC6
colocalize by mass spectrometry studies of complexes (View interaction)
PsbH
,
Lhcb4,1
,
Lhcb4,2
,
STN7
,
D1
,
D2
,
CP43
,
TSP9
,
CaS
,
PsaP
,
Alb3
,
PsbL
,
Rubisco
,
Unknown
,
Unknown
,
OEP6
,
pTAC16
,
PGRL1A
,
Unknown
,
Unknown
and
PsbQ
colocalize by mass spectrometry studies of complexes (View interaction)
Flächenentwicklungen für Wohnzwecke
Authors: Iwanow Irene , Stutzriemer Sylke
Published: April 2012

Einleitung

Wohnen als existentielles Grundbedürfnis des Menschen machte bei Bevölkerungswachstum Wohnbaulandausweisungen der Kommunen dringend erforderlich. Diese Praxis gilt es unter den Bedingungen von Haushaltsschrumpfung kritisch zu überprüfen. Der Beitrag stellt die Wohnwünsche als wichtige Triebkraft des weiteren Flächenwachstums für Wohnen heraus und weist auf die im Leibniz-Institut für ökologische Raumentwicklung (IÖR) entwickelten neuen Ansätze und deren Nutzungsmöglichkeiten hin.
With a little help from my friends – Nachbarschaft und Gesundheit
Authors: Richter-Kornweitz Antje
Published: April 2012

Einleitung

Nachbarschaftliche Netzwerke haben ein gesundheitsförderndes Potenzial, das in gemeinsam verfolgten Zielen, vertrauensvollen Beziehungen und sozialem Zusammenhalt liegt. Zu klären ist, was genau unter Nachbarschaft zu verstehen ist und wie unterstützende nachbarschaftliche Beziehungen auch in strukturell benachteiligten Settings entstehen. Die lokalen Bedingungen vor Ort lassen sich durch eine Bestandsaufnahme erheben. Komplizierter ist die Frage nach Erreichbarkeit und Einbeziehung der Bewohnerschaft selbst sowie die Unterstützung von Selbstorganisation im Setting. Zu den Erfolgsfaktoren gehört neben äußeren Rahmenbedingungen eine spezifische innere Haltung als Grundlage professionellen Handels, die als Kompetenz dringend von Public Health vermittelt werden sollte.
,,Stadtblau‘‘ – die Renaissance eines gesundheitsförderlichen Faktors
Authors: Völker Sebastian , Claßen Thomas , Baumeister Hendrik , Kistemann Thomas
Published: April 2012

Einleitung

Die Grundlage jeder gesellschaftlichen Entwicklung bildet das Wasser. Aus historischer Perspektive fanden Siedlungsgründungen vor allem an Wasserlagen statt. Diese stellten das Grundnahrungsmittel Wasser bereit, fungierten als Basis für landwirtschaftliche Produktion, erfüllten vielfältige Funktionen, wie bspw. hygienische, logistische und militärische. In der post-industriellen Stadtentwicklung wurde „Stadtblau“ (Kistemann et al., 2010) als attraktiver Standortfaktor von Planern wiederentdeckt (Breen und Rigby, 1996).
The ICC's Potential for Doing Bad When Pursuing Good
Authors: Schiff Benjamin
Published: April 2012

The International Criminal Court (ICC) seeks to end impunity for the atrocity crimes of genocide, crimes against humanity, war crimes, and, eventually, crimes of aggression. My contribution to this discussion takes a consequentialist view to outline ethical hazards confronting the court. Since the ICC has only recently begun to operate, with its first suspect, Thomas Lubanga Dyilo of the Democratic Republic of Congo, arriving in The Hague in 2006 and his trial completed only in the fall of 2011 (and awaiting a verdict in 2012), it is too early to reach a general appraisal of the court's effects.
In Defense of Smart Sanctions: A Response to Joy Gordon
Authors: Lopez George A.
Published: April 2012

In her recent article in this journal, Joy Gordon provides an astute history and critique of the evolution and application of smart sanctions within the United Nations system since the mid-1990s. Her analysis of the strengths and weaknesses of the discrete types of smart sanctions is part of a growing discussion among both academics and practitioners about the future and the utility of these measures. As always, her continued skepticism about the effectiveness and ethical dimensions of economic sanctions deserves serious consideration and evaluation. In particular, Gordon raises three central concerns: (1) smart sanctions are no more successful than traditional trade sanctions; (2) each type of targeted mechanism has serious flaws; and (3) targeted sanctions did not end the humanitarian damage or the related ethical dilemmas that are embedded into sanctions design and implementation.
Almost Saving Whales: The Ambiguity of Success at the International Whaling Commission
Authors: Hurd Ian
Published: April 2012

The international regulation of whaling has been a tremendous success. It has reduced whale hunting dramatically from its peak in the 1960s and brought almost all species of whales out of danger of extinction. Today, whaling conservation stands as a—or perhaps the—paradigm of a successful international regime. Yet the international organization responsible for this success is itself in such crisis that it may not survive.
After the MDGs: Citizen Deliberation and the Post-2015 Development Framework
Authors: Wisor Scott
Published: April 2012

The Millennium Development Goals (MDGs), an unprecedented set of global commitments to reduce various forms of human deprivation and promote human development, are set to expire in 2015. Despite their promise, the MDGs are flawed in a variety of ways. The development community is already discussing what improved development framework should replace the MDGs. I argue that global justice advocates should focus first on the procedure for developing the post-2015 development framework. Specifically, they should create spaces for citizens, especially the most marginalized and oppressed, to actively deliberate about the form and content of a future global development framework, and ensure that this deliberation receives political uptake in formal intergovernmental processes for deciding the post-2015 framework.
Toward a Global Ethic
Authors: Rodin David
Published: April 2012

We are one humanity, but seven billion humans. This is the essential challenge of global ethics: how to accommodate the tension between our universal and particular natures. This tension is, of course, age-old and runs through all moral and political philosophy. But in the world of the early twenty-first century it plays out in distinctive new ways. Ethics has always engaged twin capacities inherent in every human: the capacity to harm and the capacity to help. But the profound set of transformations commonly referred to as globalization—the increasing mobility of goods, labor, and capital; the increasing interconnectedness of political, economic, and financial systems; and the radical empowerment of groups and individuals through technology—have enabled us to harm and to help others in ways that our forebears could not have imagined. What we require from a global ethic is shaped by these transformative forces; and global ethics—the success or failure of that project—will substantially shape the course of the twenty-first century.
Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis
Authors: Wauthier C. , Cayol V. , Kervyn F. , d'Oreye N.
Published: April 2012

On 17 January 2002, Nyiragongo volcano erupted along a 20 km‐long fracture network extending from the volcano to the city of Goma. The event was captured by InSAR data from the ERS‐2 and RADARSAT‐1 satellites. A combination of 3D numerical modeling and inversions is used to analyze these displacements. Using Akaike Information Criteria, we determine that a model with two subvertical dikes is the most likely explanation for the 2002 InSAR deformation signal. A first, shallow dike, 2 km high, is associated with the eruptive fissure, and a second, deeper dike, 6 km high and 40 km long, lies about 3 km below the city of Goma. As the deep dike extends laterally for 20 km beneath the gas‐rich Lake Kivu, the interaction of magma and dissolved gas should be considered as a significant hazard for future eruptions. A likely scenario for the eruption is that the magma supply to a deep reservoir started ten months before the eruption, as indicated by LP events and tremor. Stress analysis indicates that the deep dike could have triggered the injection of magma from the lake and shallow reservoir into the eruptive dike. The deep dike induced the opening of the southern part of this shallow dike, to which it transmitted magma though a narrow dike. This model is consistent with the geochemical analysis, the lava rheology and the pre‐ and post‐eruptive seismicity. We infer low overpressures (1–10 MPa) for the dikes. These values are consistent with lithostatic crustal stresses close to the dikes and low magma pressure. As a consequence, the dike direction is probably not controlled by stresses but rather by a reduced tensile strength, inherited from previous rift intrusions. The lithostatic stresses indicate that magmatic activity is intense enough to relax tensional stresses associated with the rift extension.
The role of outcrop‐to‐outcrop fluid flow in off‐axis oceanic hydrothermal systems under abyssal sedimentation conditions
Authors: Anderson B. W. , Coogan L. A. , Gillis K. M.
Published: April 2012

It has been proposed that ridge flank hydrothermal circulation by outcrop‐to‐outcrop (lateral) flow may be the dominant mode of oceanic hydrothermal circulation globally. In this model, the upper igneous crust is an aquifer overlain by low permeability sediments, and aquifer‐ocean fluid exchange occurs through basement outcrops. Thermally induced pressure gradients drive fluid laterally from recharge outcrops to discharge outcrops. To test the global applicability of outcrop‐to‐outcrop flow, models of synthetic basement bathymetry representative of crust formed at different spreading rates, pelagic sediment supply and post depositional transport, and sediment hydraulic impedance are used to quantify the time‐varying distribution of sediment and basement outcrops globally. Results suggest that basement outcrops may be 40–50% closer together than previously estimated. The modeled sediment and outcrop results are coupled with a two‐dimensional model of outcrop‐to‐outcrop fluid flow and heat exchange in a vertically isothermal crustal aquifer to predict the spatial distributions of seafloor heat flow within the simulation region under this mode of hydrothermal circulation. It is found that both the time‐varying average and standard deviation of modeled seafloor heat flow required by outcrop‐to‐outcrop flow simultaneously fit the global heat flow data if the average aquifer permeability decreases from ∼10−9 m2 to ∼10−11 m2 over the duration of the global heat flow deficit (to ∼65 Myr). This permeability range is consistent with other estimates of upper crustal permeability on comparable spatial scales, and supports the proposition that outcrop‐to‐outcrop fluid flow may be the dominant mode of off‐axis hydrothermal circulation globally.
Resolute Bay CADI ionosonde drifts, PolarDARN HF velocities, and cross polar cap potential
Authors: Mori D. , Koustov A. V. , Jayachandran P. T. , Nishitani N.
Published: April 2012

In this study, velocities measured by the Rankin Inlet and Inuvik PolarDARN HF radars over Resolute Bay (RB) are compared with measurements from the RB CADI ionosonde to investigate the consistency of the measurements. Two types of comparisons are performed: 1‐D, where each PolarDARN radar line‐of‐sight velocity is plotted against CADI velocity projected onto appropriate radar beam, and 2‐D, where the PolarDARN merged velocity is compared with the full CADI vector. In both cases, velocities were found to statistically agree. For the 1‐D comparison, the velocities were comparable in ∼85% of cases. For the 2‐D comparison, a minor tendency for larger PolarDARN merge velocities (∼60 m/s) was noticed. The second task performed is a comparison of the SuperDARN cross polar cap potential (CPCP) and the CADI‐based CPCP and their dependence on the CADI velocity. Linear dependences were found allowing for inter‐conversion between these parameters. For large plasma drifts, the SuperDARN CPCPs were found to be much smaller than the CADI‐based CPCPs hinting that the separation between the foci of a large‐scale convection pattern is often underestimated in the SuperDARN convection mapping.
A 21st century shift in the relationship between ENSO SST and warm water volume anomalies
Authors: McPhaden Michael J.
Published: April 2012

This paper documents changes in the relationship between warm water volume (WWV), which is an index for upper ocean heat content, and El Niño/Southern Oscillation (ENSO) SST anomalies during the period 1980–2010. Upper ocean heat content represents a major source of predictability for ENSO, with WWV integrated along the equator leading ENSO SST anomalies by 2–3 seasons during the 1980s and 1990s. For the first decade of the 21st century however, WWV variations decreased and lead time was reduced to only one season, mainly due to the diminished persistence of WWV anomalies early in the calendar year. These changes are linked to a shift towards more central Pacific (CP) versus eastern Pacific (EP) El Niños in the past decade. The results are consistent with a reduced impact of thermocline feedbacks on ENSO SST development and potentially imply reduced seasonal time scale predictability during periods dominated by CP El Niños.
Sperm counts and fertility in men: a rocky road ahead
Authors: Sharpe Richard M
Published: April 2012

Declining sperm counts and the increasing average age of first‐time parents spell trouble for human fertility, especially when set against the backdrop of ageing populations.
The new geography of scientific collaborations
Authors: Vasconcelos Sonia M R , Steneck Nicholas H , Anderson Melissa , Masuda Hatisaburo , Palacios Marisa , Pinto José C S , Sorenson Martha M
Published: April 2012

The science ethics melting pot is just heating up; what role will emerging nations play in setting new standards of practice that ensure successful international collaborations?
Enhancers: emerging roles in cell fate specification
Authors: Ong Chin‐Tong , Corces Victor G
Published: April 2012

Enhancers are regulatory DNA elements that dictate the spatial and temporal patterns of gene expression during development. Recent evidence suggests that the distinct chromatin features of enhancer regions provide the permissive landscape required for the differential access of diverse signalling molecules that drive cell‐specific gene expression programmes. The epigenetic patterning of enhancers occurs before cell fate decisions, suggesting that the epigenetic information required for subsequent differentiation processes is embedded within the enhancer element. Lineage studies indicate that the patterning of enhancers might be regulated by the intricate interplay between DNA methylation status, the binding of specific transcription factors to enhancers and existing histone modifications. In this review, we present insights into the mechanisms of enhancer function, which might ultimately facilitate cell reprogramming strategies for use in regenerative medicine.
Adsorption dynamics of ethylene on Si(001)
Authors: Lipponer M. A. , Armbrust N. , Dürr M. , Höfer U.
Published: April 2012

The dynamics of ethylene adsorption on the Si(001) surface was investigated by means of molecular beam techniques. A constant decrease of initial sticking probability s0 was observed with increasing kinetic energy indicating a non-activated adsorption channel. With increasing surface temperature, s0 decreases as well, pointing towards adsorption via a precursor state. Quantitative evaluation of the temperature dependence of s0 via the Kisliuk model was possible for surface temperatures above 250 K; below that value, the temperature dependence is dominated by the adsorption dynamics into the precursor state. Maximum surface coverage was found to be reduced with increasing surface temperature, which is discussed on the basis of a long lifetime of the precursor state at low temperatures.
Magnetic and chemical order-disorder transformations in Co2Fe(Ga1−xSix) and Co2Fe(Al1−ySiy) Heusler alloys
Authors: Umetsu Rie Y. , Okubo Akinari , Kainuma Ryosuke
Published: April 2012

The concentration dependence of the order-disorder phase transformation temperature from the L21 to the B2 phase (TtL21/B2) and magnetic properties of Co2Fe(Ga1−xSix) and Co2Fe(Al1−ySiy) Heusler alloys were investigated. In the phase diagrams, a crossover of the Curie temperature (TC) and TtL21/B2 was confirmed at around y = 0.45 in Co2Fe(Al1−ySiy), whereas the TC and TtL21/B2 monotonically changed with x in Co2Fe (Ga1−xSix). The slopes of the linear concentration dependence of TtL21/B2 for Co2Fe(Al1−ySiy) drastically changed at about y = 0.45, suggesting that the chemical interchange energy between Fe and Al in Co2FeAl alloy is affected by the magnetic ordering.
Spectral engineering of LaF3:Ce3+ nanoparticles: The role of Ce3+ in surface sites
Authors: Jacobsohn L. G. , Toncelli A. , Sprinkle K. B. , Kucera C. J. , Ballato J.
Published: April 2012

Due to the high surface-to-volume ratio, luminescence centers on the surface have relative dominance in the overall spectral response of nanoparticles. The luminescence of LaF3:Ce3+ nanoparticles was investigated in the spectral and temporal domains with a particular focus on the role of Ce3+ on the surface. These nanoparticles present two luminescence bands at 4.10 eV and 4.37 eV attributed to Ce3+ transitions from the 5d level to the spin-orbit split 4f ground levels 2F5/2 and 2F7/2, in addition to a low-energy band at 3.62 eV that has been attributed to Ce3+ ions residing in perturbed sites. The growth of up to three undoped shells, ca. 0.9 nm thick each, around the core promoted a progressive enhancement of luminescence output, concomitant with an increase in the fluorescence lifetime due to the weakening of energy transfer through multipolar interaction between Ce3+ in the core and quenching defects on the surface. Also, the growth of the first shell led to a decrease in the relative intensity of the low-energy band and a 0.23 eV shift to higher energies. These results were interpreted as being due to the existence of two types of perturbed sites, one on the surface that is eliminated by the growth of the first shell, and another within the volume of the nanoparticle, similar to observations in bulk single crystals. This work demonstrates how surface engineering can affect and control the luminescence behavior of this nanomaterial.
Two-dimensional simulations of nonlinear beam-plasma interaction in isotropic and magnetized plasmas
Authors: Timofeev I. V.
Published: April 2012

Nonlinear interaction of a low density electron beam with an uniform plasma is studied using two-dimensional particle-in-cell simulations. We focus on formation of coherent phase space structures in the case, when a wide two-dimensional wave spectrum is driven unstable, and we also study how nonlinear evolution of these structures is affected by the external magnetic field. In the case of isotropic plasma, nonlinear buildup of filamentation modes due to the combined effects of two-stream and oblique instabilities is found to exist and growth mechanisms of secondary instabilities destroying the Bernstein-Green-Kruskal–type nonlinear wave are identified. In the weak magnetic field, the energy of beam-excited plasma waves at the nonlinear stage of beam-plasma interaction goes predominantly to the short-wavelength upper-hybrid waves propagating parallel to the magnetic field, whereas in the strong magnetic field, the spectral energy is transferred to the electrostatic whistlers with oblique propagation.
A graphene electron lens
Authors: Gerhard L. , Moyen E. , Balashov T. , Ozerov I. , Portail M. , Sahaf H. , Masson L. , Wulfhekel W. , Hanbücken M.
Published: April 2012

An epitaxial layer of graphene was grown on a pre patterned 6H-SiC(0001) crystal. The graphene smoothly covers the hexagonal nano-holes in the substrate without the introduction of small angle grain boundaries or dislocations. This is achieved by an elastic deformation of the graphene by ≈0.3% in accordance to its large elastic strain limit. This elastic stretching of the graphene leads to a modification of the band structure and to a local lowering of the electron group velocity of the graphene. We propose to use this effect to focus two-dimensional electrons in analogy to simple optical lenses.
Droplet spreading on a porous surface: A lattice Boltzmann study
Authors: Frank X. , Perré P.
Published: April 2012

This paper presents an investigation into drop spreading and capillary absorption at the surface of a porous substrate. Lattice Boltzmann numerical simulations are carried out at the pore level with two values of intrinsic contact angle at the liquid-gas-solid line and three values of porosity; the case of a flat solid surface is included as a reference. The numerical results show a power-law evolution of the wetted zone radius with time, both exponent and prefactor decreasing with increasing porosity. The evolution in time of the droplet height emerges from competition between pure spreading and bulk capillary imbibition in the porous medium.
A highly tunable heterostructure metal-semiconductor-metal capacitor utilizing embedded 2-dimensional charge
Authors: Dianat P. , Prusak R. W. , Gallo E. , Cola A. , Persano A. , Quaranta F. , Nabet B.
Published: April 2012

We report on a variable capacitor that is formed between Schottky contacts and the two dimensional electron gas (2DEG) in a planar metal-semiconductor-metal structure. Device capacitance at low bias is twice the series capacitance of anode and cathode, enhancing to a maximum value, Cmax, at a threshold voltage, before reaching a minimum, Cmin, lower than the geometric capacitance of the coplanar contacts, thus resulting in ultra high Cmax/Cmin tuning ratio. Sensitivity, the normalized change of capacitance with voltage, is also very large. The dense reservoir of the 2DEG charge maintained between contacts is shown to be responsible for this remarkable performance.
Isotope separation of 17O by photodissociation of ozone with near-infrared laser irradiation
Authors: Hayashida Shigeru , Kambe Takashi , Sato Tetsuya , Igarashi Takehiro , Kuze Hiroaki
Published: April 2012

Oxygen-17 is a stable oxygen isotope useful for various diagnostics in both engineering and medical applications. Enrichment of 17O, however, has been very costly due to the lack of appropriate methods that enable efficient production of 17O on an industrial level. In this paper, we report the first 17O-selective photodissociation of ozone at a relatively high pressure, which has been achieved by irradiating a gas mixture of 10 vol% O3-90 vol% CF4 with narrowband laser. The experiment was conducted on a pilot-plant scale. A total laser power of 1.6 W was generated by external-cavity diode lasers with all the laser wavelengths fixed at the peak of an absorption line of 16O16O17O around 1 μm. The beams were introduced into a 25 -m long photoreaction cell under the sealed-off condition with a total pressure of 20 kPa. Lower cell temperature reduced the background decomposition of ozone, and at the temperature of 158 K, an 17O enrichment factor of 2.2 was attained.
Conditional photon-assisted transport in coupled quantum dot
Authors: Xie Yan , Xie Weidong , Duan Suqing , Yang Ning , Chen Jing , Zhang Wei , Chu Weidong , Zhao Xian-Geng
Published: April 2012

We theoretically study the photon-assisted transport (PAT) in a double quantum dot (QD) which is conditionally controlled by the optical excitation in an adjacent QD. Based on a real three-QD model, a double-electron level configuration needed for the conditional PAT is designed. Interesting conditional dynamics are demonstrated for the double QD and its adjacent QD. Depending on various conditional frequencies, the conditional behaviors can be manifested as the current peaks or collapses of the PAT. They correspond to coherent excitations or trapping of double-electron states. Our results present a possible way to optically manipulate electron states and monitor them via the signals of current spectrum.
Atomic crystal structure of ordered In3Sb1Te2 ternary alloy studied by high-resolution transmission electron microscopy
Authors: Soo Kim Chung , Yong Lee Jeong , Tae Kim Yong
Published: April 2012

The atomic structure of In3Sb1Te2 was investigated by high-resolution transmission electron microscopy (HRTEM) and the National Center for Electron Microscopy Simulation System. In3Sb1Te2 has a disordered NaCl structure; In atoms are positioned in a face-centered cubic lattice, and Sb and Te atoms are located at randomly occupied octahedral sites. However, the observed HRTEM images of the ordered In3Sb1Te2 phase show that Sb and Te atoms are located in specific positions, that is, at the center and edge of the unit cell, respectively. The atomic model of the ordered In3Sb1Te2 is confirmed by simulated images, which match the experimental HRTEM images.
Phase and amplitude sensitive scanning microwave microscopy/spectroscopy on metal–oxide–semiconductor systems
Authors: Humer I. , Huber H. P. , Kienberger F. , Danzberger J. , Smoliner J.
Published: April 2012

In this paper, an analytical model for phase and amplitude sensitive scanning microwave microscopy on metal–oxide–semiconductor structures is presented. The phase and amplitude of the microwave signals are calculated as a function of operation frequency, oxide thickness, tip radius, bias, and doping level. For doping profiling applications it is found that both the microwave amplitude and phase signals can be used. Under appropriate operation conditions, the phase signals can be larger by a factor of 40. Series resistances turn out to be problematic as they lead to non–monotonic contrast at low doping levels. The phase and amplitude behavior on a material system with a frequency dependent dielectric constant is also investigated and the possibilities of complex impedance spectroscopy are explored.
Equifrequency curve dispersion in dielectric-loaded plasmonic crystals
Authors: Regan C. J. , Grave de Peralta L. , Bernussi A. A.
Published: April 2012

We present a quantitative description of the momentum-space dispersion and directivity of light propagation in dielectric-loaded plasmonic crystals. In our analysis the three-dimensional lossy plasmonic crystals are modeled by two-dimensional lossless dielectric crystals with real effective refractive indexes. Simulated equifrequency curves are in excellent agreement with measured Fourier plane images obtained from dye-doped dielectric-loaded plasmonic crystals with different lattice geometries and parameters. Our results provide fundamental information about the origin of the directional bandgaps in these structures.
Silicon-nanocrystal resonant-cavity light emitting devices for color tailoring
Authors: Tseng Chih-Kuo , Lee Ming-Chang M. , Hung Hau-Wei , Huang Jiun-Ru , Lee Kun-Yu , Shieh Jia-Min , Lin Gong-Ru
Published: April 2012

A silicon-nanocrsytal resonant-cavity light-emitting device (RCLED) is presented. The microcavity, made by a silicon nanocrystal layer inserted between a semitransparent Au reflector and a distributed Bragg reflector mirror, shows enhanced emission intensity by four times at resonance wavelength and 1/8 narrow emission spectrum compared to nonresonant devices. The external quantum efficiency and power conversion efficiency also increase by 3.5 times. Multiple colors, green, green-yellow, orange, and red are displayed by adjusting the cavity length of RCLED.
Investigation of the phase separation of Al-Bi immiscible alloy melts by viscosity measurements
Authors: Wu Yuqin , Li Chuanjun
Published: April 2012

The viscosity dependence of immiscible alloys, such as Al96Bi4, Al93Bi7, Al90Bi10 and pure Bi on temperature was measured using a torsional oscillation viscometer. The variation in viscosity with temperature deviated from the Arrhenius equation near the critical temperature. The temperature dependence of the viscosity near the critical temperature could be fitted using an amended viscosity equation based on the critical dynamics theory and gas-like property of metal melts. For the amended viscosity, the activation energy is a function of temperature Ev(T) = E0 + TScf. The change in molecular degree of order is reflected by the configuration entropy, Scf. For the pure Bi melt, during the solidification process, the molecular degree of order of the melt increased and achieved long range order. For the Al-Bi immiscible alloys, the molecular degree of order increased and achieved phase separation.
In situ surface pre-treatment study of GaAs and In0.53Ga0.47As
Authors: Brennan B. , Zhernokletov D. M. , Dong H. , Hinkle C. L. , Kim J. , Wallace R. M.
Published: April 2012

The impact of using multiple cycles of trimethyl-aluminum (TMA) prior to Al2O3 deposition on the properties of (NH4)2S treated In0.53Ga0.47As and GaAs substrates was investigated by in situ x-ray photoelectron spectroscopy. Increasing the number of TMA cycles prior to Al2O3 atomic layer deposition (ALD) was seen to decrease the concentration of As-As detected at the oxide-semiconductor interface. The impact of annealing the (NH4)2S treated GaAs surface in situ prior to ALD, in various environments, was also investigated.
Study of droop phenomena in InGaN-based blue and green light-emitting diodes by temperature-dependent electroluminescence
Authors: Shin Dong-Soo , Han Dong-Pyo , Oh Ji-Yeon , Shim Jong-In
Published: April 2012

InGaN-based blue and green light-emitting diodes are studied by temperature-dependent electroluminescence (EL) from 300 to 50 K to elucidate the effects of carrier overflow and the saturation in radiative recombination rate on the efficiency droop. Severe efficiency droop at cryogenic temperatures is attributed to the carrier overflow, which is confirmed by the EL spectra. The degree of overflow is thought to be related to the reduced effective active volume and the subsequent saturation in radiative recombination rate. Carrier transport and indium clustering in the active region are discussed in relation to the reduced effective active volume.
The Role of Vision in Auditory Distance Perception
Authors: Calcagno Esteban R , Abregú Ezequiel L , Eguía Manuel C , Vergara Ramiro
Published: April 2012

In humans, multisensory interaction is an important strategy for improving the detection of stimuli of different nature and reducing the variability of response. It is known that the presence of visual information affects the auditory perception in the horizontal plane (azimuth), but there are few researches that study the influence of vision in the auditory distance perception. In general, the data obtained from these studies are contradictory and do not completely define the way in which visual cues affect the apparent distance of a sound source. Here psychophysical experiments on auditory distance perception in humans are performed, including and excluding visual cues. The results show that the apparent distance from the source is affected by the presence of visual information and that subjects can store in their memory a representation of the environment that later improves the perception of distance.
Effects of maternal nutrition during pregnancy on fetal growth and maternal constraint in sheep
Authors: Jenkinson C. M. C. , Earl A. K. , Kenyon P. R. , Blair H. T.
Published: April 2012

This study set out to determine the stage of gestation at which maternal constraint on fetal growth occurs and whether pregnancy nutritional level could alleviate that constraint. One-hundred and thirty-eight Cheviot (C) and 114 Suffolk (S) ewes were split into two groups and bred with either 12 S or 12 C rams to generate four ewe/fetal groups CC (C dam and C sire), CSinC (crossbred fetus in C ewe), CSinS, and SS. At Day 21 of pregnancy (P21), half of the ewes in each of the four groups were randomly allocated to either a maintenance (M) or ad libitum (A) nutritional treatment, under pastoral grazing conditions. At P100, a subgroup of singleton-bearing ewes including ewes from all four groups (n = 55 in total) were euthanised (Study 1). Maternal, placental and fetal weights and sizes were recorded. The remaining ewes were fed to appetite from P140 and were allowed to lamb (n = 114 in total, Study 2) and lamb liveweights were recorded within 12 h of birth and at average days 30 and 100 (L30, L100) of lactation.
In both studies, M ewes were lighter (P < 0.05) than A ewes, and CC and CSinC ewes were lighter (P < 0.05) than CSinS and SS ewes. In Study 1, maternal nutritional treatment had no effect (P > 0.05) on fetal bodyweight although fetuses from A ewes had heavier (P < 0.05) livers, spleens and thyroids than fetuses from M ewes. CC and CSinC fetuses were lighter (P < 0.01) than both CSinS and SS fetuses.
In Study 2, lambs born to M ewes were lighter (P < 0.05) at birth and at L100 than lambs born to A ewes. CC lambs were lighter (P < 0.01) than CSinC, CSinS and SS lambs at birth. At L30 and L100, CC lambs were lighter (P < 0.05) than CSinC lambs, which, in turn, were lighter (P < 0.05) than both CSinS and SS lambs, which did not differ (P > 0.05). Combined, these studies indicate that maternal nutrition may have little impact on singleton-offspring development until late gestation while, in contrast, dam size affected fetal size by the end of the second trimester. These data suggest that the C ewe constrains the growth of the crossbred fetus well before a ‘physical’ constraint would be expected.
Pollen morphology of the Myrtaceae. Part 2: tribes Backhousieae, Melaleuceae, Metrosidereae, Osbornieae and Syzygieae
Authors: Thornhill Andrew H. , Hope Geoff S. , Craven Lyn A. , Crisp Michael D.
Published: April 2012

Pollen morphology of 16 genera and 101 species from the Myrtaceae tribes Backhousieae, Melaleuceae, Metrosidereae, Osbornieae and Syzygieae was surveyed using scanning electron microscopy (SEM) and light microscopy (LM). The most common pollen type observed in these tribes was parasyncolpate with arcuate or angular colpi, and a rugulate exine pattern. There was little size variation in observed pollen, except for larger pollen in tribe Melaleuceae. All Metrosideros pollen grains had apocolpial islands, as well as all Callistemon species viewed by LM. Choricarpia of tribe Backhousieae had pollen with a distinctive exine pattern. Dicolporate pollen were observed in two tribes, Metrosidereae (Tepualia) and Syzygieae (Acmena), and may be of systematic value. The dicolporate grains of these two genera were also easily distinguishable from each other by using size and pollen side shape as diagnostic characters. Two pollen types were observed within the genus Melaleuca, and a number of pollen types were observed within the species-rich genus Syzygium.
Spinal 12-lipoxygenase-derived hepoxilin A3contributes to inflammatory hyperalgesia via activation of TRPV1 and TRPA1 receptors
Authors: Gregus Ann M. , Doolen Suzanne , Dumlao Darren S. , Buczynski Matthew W. , Takasusuki Toshifumi , Fitzsimmons Bethany L. , Hua Xiao-Ying , Taylor Bradley K. , Dennis Edward A. , Yaksh Tony L.
Published: April 2012

Peripheral inflammation initiates changes in spinal nociceptive processing leading to hyperalgesia. Previously, we demonstrated that among 102 lipid species detected by LC-MS/MS analysis in rat spinal cord, the most notable increases that occur after intraplantar carrageenan are metabolites of 12-lipoxygenases (12-LOX), particularly hepoxilins (HXA3and HXB3). Thus, we examined involvement of spinal LOX enzymes in inflammatory hyperalgesia. In the current work, we found that intrathecal (IT) delivery of the LOX inhibitor nordihydroguaiaretic acid prevented the carrageenan-evoked increase in spinal HXB3at doses that attenuated the associated hyperalgesia. Furthermore, IT delivery of inhibitors targeting 12-LOX (CDC, Baicalein), but not 5-LOX (Zileuton) dose-dependently attenuated tactile allodynia. Similarly, IT delivery of 12-LOX metabolites of arachidonic acid 12(S)-HpETE, 12(S)-HETE, HXA3, or HXB3evoked profound, persistent tactile allodynia, but 12(S)-HpETE and HXA3produced relatively modest, transient heat hyperalgesia. The pronociceptive effect of HXA3correlated with enhanced release of Substance P from primary sensory afferents. Importantly, HXA3triggered sustained mobilization of calcium in cells stably overexpressing TRPV1 or TRPA1 receptors and in acutely dissociated rodent sensory neurons. Constitutive deletion or antagonists of TRPV1 (AMG9810) or TRPA1 (HC030031) attenuated this action. Furthermore, pretreatment with antihyperalgesic doses of AMG9810 or HC030031 reduced spinal HXA3-evoked allodynia. These data indicate that spinal HXA3is increased by peripheral inflammation and promotes initiation of facilitated nociceptive processing through direct activation of TRPV1 and TRPA1 at central terminals.
Mast cells orchestrate type 2 immunity to helminths through regulation of tissue-derived cytokines
Authors: Hepworth Matthew R. , Daniłowicz-Luebert Emilia , Rausch Sebastian , Metz Martin , Klotz Christian , Maurer Marcus , Hartmann Susanne
Published: April 2012

Mast cells (MCs) are potent inflammatory cells that are distributed throughout mucosal barrier tissues and respond rapidly to pathogenic stimuli. During helminth infections, MCs play an important role as late-stage effectors. However, it is currently unknown whether MCs contribute to the early innate events that determine the priming of adaptive immunity. MC-deficient mouse strains and mice treated with the MC stabilizing agent cromolyn sodium had dramatically reduced Th2 priming and type 2 cytokine production and harbored increased parasite burdens following infection with gastrointestinal helminths (
Heligmosomoides polygyrus bakeri
and
Trichuris muris
). In addition, early production of the tissue-derived cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) was significantly diminished in MC-deficient mice and resulted in decreased numbers of infection-elicited IL-25–dependent (Lin
−
CD45
−
)CD34
+
Sca-1
+
progenitors, which produced type 2 cytokines and could be differentiated into mast cells ex vivo. Finally, repair of MC deficiency increased production of IL-25, IL-33, and TSLP, restored progenitor cell numbers and Th2 priming, and reduced parasite burden. Our data reveal an innate IgE-independent role for MCs in orchestrating type 2 immune responses via the regulation of IL-25, IL-33, and TSLP.
Neurofibromatosis-like phenotype in
Drosophila
caused by lack of glucosylceramide extension
Authors: Dahlgaard Katja , Jung Anita , Qvortrup Klaus , Clausen Henrik , Kjaerulff Ole , Wandall Hans H.
Published: April 2012

Glycosphingolipids (GSLs) are of fundamental importance in the nervous system. However, the molecular details associated with GSL function are largely unknown, in part because of the complexity of GSL biosynthesis in vertebrates. In
Drosophila
, only one major GSL biosynthetic pathway exists, controlled by the glycosyltransferase Egghead (Egh). Here we discovered that loss of Egh causes overgrowth of peripheral nerves and attraction of immune cells to the nerves. This phenotype is reminiscent of the human disorder neurofibromatosis type 1, which is characterized by disfiguring nerve sheath tumors with mast cell infiltration, increased cancer risk, and learning deficits. Neurofibromatosis type 1 is due to a reduction of the tumor suppressor neurofibromin, a negative regulator of the small GTPase Ras. Enhanced Ras signaling promotes glial growth through activation of phosphatidylinositol 3-kinase (PI3K) and its downstream kinase Akt. We find that overgrowth of peripheral nerves in
egh
mutants is suppressed by down-regulation of the PI3K signaling pathway by expression of either dominant-negative PI3K, the tumor suppressor PTEN, or the transcription factor FOXO in the subperineurial glia. These results show that loss of the glycosyltransferase Egh affects membrane signaling and activation of PI3K signaling in glia of the peripheral nervous system, and suggest that glycosyltransferases may suppress proliferation.
Members of the NODE (Nanog and Oct4-associated deacetylase) complex and SOX-2 promote the initiation of a natural cellular reprogramming event in vivo
Authors: Kagias Konstantinos , Ahier Arnaud , Fischer Nadine , Jarriault Sophie
Published: April 2012

Differentiated cells can be forced to change identity, either to directly adopt another differentiated identity or to revert to a pluripotent state. Direct reprogramming events can also occur naturally. We recently characterized such an event in
Caenorhabditis elegans
, in which a rectal cell switches to a neuronal cell. Here we have used this single-cell paradigm to investigate the molecular requirements of direct cell-type conversion, with a focus on the early steps. Our genetic analyses revealed the requirement of
sem-4/Sall
,
egl-27/Mta
, and
ceh-6/Oct
, members of the NODE complex recently identified in embryonic stem (ES) cells, and of the OCT4 partner
sox-2
, for the initiation of this natural direct reprogramming event. These four factors have been shown to individually impact on ES cell pluripotency; however, whether they act together to control cellular potential during development remained an open question. We further found that, in addition to acting at the same time, these factors physically associate, suggesting that they could act together as a NODE-like complex during this in vivo process. Finally, we have elucidated the functional domains in EGL-27/MTA that mediate its reprogramming activity in this system and have found that modulation of the posterior HOX protein EGL-5 is a downstream event to allow the initiation of Y identity change. Our data reveal unique in vivo functions in a natural direct reprogramming event for these genes that impact on ES cells pluripotency and suggest that conserved nuclear events could be shared between different cell plasticity phenomena across phyla.
Clathrin-mediated endocytosis is inhibited during mitosis
Authors: Fielding Andrew B. , Willox Anna K. , Okeke Emmanuel , Royle Stephen J.
Published: April 2012

A long-standing paradigm in cell biology is the shutdown of endocytosis during mitosis. There is consensus that transferrin uptake is inhibited after entry into prophase and that it resumes in telophase. A recent study proposed that endocytosis is continuous throughout the cell cycle and that the observed inhibition of transferrin uptake is due to a decrease in available transferrin receptor at the cell surface, and not to a shutdown of endocytosis. This challenge to the established view is gradually becoming accepted. Because of this controversy, we revisited the question of endocytic activity during mitosis. Using an antibody uptake assay and controlling for potential changes in surface receptor density, we demonstrate the strong inhibition of endocytosis in mitosis of CD8 chimeras containing any of the three major internalization motifs for clathrin-mediated endocytosis (YXXΦ, [DE]XXXL[LI], or FXNPXY) or a CD8 protein with the cytoplasmic tail of the cation-independent mannose 6-phosphate receptor. The shutdown is not gradual: We describe a binary switch from endocytosis being “on” in interphase to “off” in mitosis as cells traverse the G
2
/M checkpoint. In addition, we show that the inhibition of transferrin uptake in mitosis occurs despite abundant transferrin receptor at the surface of HeLa cells. Our study finds no support for the recent idea that endocytosis continues during mitosis, and we conclude that endocytosis is temporarily shutdown during early mitosis.