bluuebunny/crossref_metadata_2025 huggingface dataset:
Transboundary seabird conservation in an important North American marine ecoregion
Authors: WOLF S. , KEITT B. , AGUIRRE-MUÑOZ A. , TERSHY B. , PALACIOS E. , CROLL D.
Published: November 2006

Many seabird species of conservation concern have large geographic ranges that span political borders, forcing conservation planners to facilitate their protection in multiple countries. Seabird conservation planning within the seabird-diverse California Current System (CCS) marine ecoregion presents an important opportunity for transboundary collaborations to better protect seabirds across the USA/México border. While seabird populations in the USA are relatively well-studied and well-protected, the status of seabird populations in the Mexican region of the CCS is not well known and seabird colonies have been virtually unprotected. This study synthesizes and supplements information on breeding seabird diversity and distribution, identifies and ranks threats to seabirds and evaluates conservation capacity in the Mexican CCS to provide a framework for transboundary seabird conservation throughout the CCS ecoregion. Island-breeding seabirds in México support 43–57% of CCS breeding individuals, 59% of CCS breeding taxa and a high level of endemism. Connectivity between populations in México and the USA is high. At least 17 of the 22 extant Mexican CCS breeding seabirds are USA/México transboundary breeders or foragers, 13 of which are federally listed in the USA or México. Introduced predators and human disturbance have caused multiple seabird population extirpations in the Mexican CCS because breeding colonies lack legal protection or enforcement. However, conservation capacity in this region has increased rapidly in recent years through the establishment of new protected areas, growth of local conservation non-governmental organizations, and increase in local community support, all of which will allow for more effective use of conservation funds. Transboundary conservation coordination would better protect CCS seabirds by facilitating restoration of seabird colonies in the Mexican CCS and enabling an ecoregion-wide prioritization of seabird conservation targets to direct funding bodies to the most cost-effective investments.
Transmission of bovine leukaemia virus within dairy herds by simulation modelling
Authors: MONTI G. E. , FRANKENA K. , De JONG M. C. M.
Published: November 2006

In Argentina, bovine leukaemia virus (BLV) infection is common in dairy herds. The country currently has a National Voluntary Control Programme but relatively few farms have enrolled. However, there is increased interest from authorities and farmers to implement regional compulsory programmes but there is scarce quantitative information of the transmission of BLV in cattle herds. This information is a prerequisite to develop effective BLV control strategies. Mathematical modelling offers ways of integrating population-level knowledge and epidemiological data to predict the outcomes of intervention scenarios. The purpose of the current paper is to gain understanding about the dynamics of the transmission of BLV in dairy herds from Argentina by simulation and to compare various BLV transmission models and select the one that is most appropriate. The hypothetical herd is conceptually described in terms of BLV status as a population of individuals that are protected by maternal antibodies (M), that are susceptible (S), that are in the latent period (E) or that are infectious (I). BLV is spread by horizontal and vertical transmission. We used an age-structured population model and within-herd transmission was simulated by Monte Carlo techniques. The next-generation approach has been used for the systematic computation of the basic reproduction ratio (R0). Parameter values for disease transmission were derived from previously published data; rates of entry, exit or transition between age groups were calculated based on our previous study, observational data, expert opinions and literature. With these parameter values the probability of a minor outbreak was estimated to be 10%, the probability of extinction was estimated as <0·001% and the expected time to extinction as more than 80 years. The probability of a minor outbreak and changes in prevalence were different when the index case was an adult cow compared to introduction by a heifer. Prediction of prevalences from MSI models fit the data satisfactorily.R0was estimated as 9·5. The sensitivity analysis onR0showed that all measures directed to reduce the transmission rate are potentially effective given operational control measures. An important prediction of these models is that, even in a relatively small, closed dairy herd, the time-scale for a BLV outbreak may be as long as several years and within-herd control of BLV requires intensive efforts.
Nano-scale MOSFET device modelling with quantum mechanical effects
Authors: CUMBERBATCH ELLIS , UNO SHIGEYASU , ABEBE HENOK
Published: November 2006

The continuing down-scaling trend of CMOS technology has brought serious deterioration in the accuracy of the SPICE (Simulation Program with Integrated Circuit Emphasis) device models used in the design of chip functions. This is due to in part to hot electron and quantum effects that occur in modern nano-scale MOSFET devices [13, 25, 28, 33, 34]. The focus of this paper is on modeling quantum confinement effects based on the Density-Gradient (DG) model [6, 9, 14], for application in SPICE. Analytic 1-D quantum mechanical (QM) effects correction formulae for the MOSFET inversion charge and electrostatic potential are derived from the DG model using matched asymptotic expansion techniques. Comparison of these new models with numerical data shows good results.
Der Ersttrimester-Test – persönliche Entscheidungshilfe oder Screeningtool der öffentlichen Gesundheitsvorsorge?
Authors: Baumann-Hölzle  , Hürlimann
Published: November 2006

Internationale Studien belegen, dass schwangere Frauen und ihre Partner nicht ausreichend über die Möglichkeiten und Grenzen des Ersttrimester-Tests informiert werden, um eine informierte Wahl für oder gegen solche Tests treffen zu können. Die Informationen werden den Betroffenen manchmal gar nicht, unvollständig oder unverständlich vermittelt. Die durch Untersuchungen belegte Möglichkeit einer sachgerechten und entscheidungsrelevanten Aufklärung wird vielfach nicht wahrgenommen. Insbesondere genügen Information nur über den Ersttrimester-Test allein für einen freien Entscheid nicht. Sobald der Test als Selbstverständlichkeit routinemäßig im Rahmen von Screeningprogrammen angeboten wird, können sich Frauen nicht frei entscheiden, denn hierfür bedarf es einer persönlichen ethischen Güterabwägung, welche hinsichtlich einer möglichen Testanwendung Kohärenz mit der Lebenswelt (Lebensentwurf und Lebenskontext) der schwangeren Frau und ihrem Partner herstellt. Bei einer persönlichen Entscheidungsfindung sollte der Ersttrimester-Test demnach eine Entscheidungshilfe und kein Screeningtool der öffentlichen Gesundheitsvorsorge sein. In der Schweiz wurde deshalb von einer interdisziplinären Arbeitsgruppe ein Beratungsmodell entwickelt, welches den persönlichen Entscheidungsfindungsprozess unterstützen soll. Das Beratungsmodell besteht aus einer Informationsbroschüre für die schwangere Frau und ihren Partner, sowie für die Ärzteschaft aus einem Gesprächs- und Informationskonzept und einer zweitägigen Schulung. Nach der Evaluation des Beratungsmodells im Rahmen eines Nationalfondsprogrammes wurde es von der Schweizerischen Gesellschaft für Gynäkologie und Geburtshilfe als Beratungsstandard übernommen. Zudem wurde es durch Empfehlungen zu den kommunikativen Fertigkeiten und ein Kurzschulungskonzept ergänzt.
Neue Möglichkeiten der pränatalen genetischen Diagnostik inklusive Präimplantationsdiagnostik
Authors: Miny  , De Geyter  , Holzgreve
Published: November 2006

Der wichtigste Fortschritt der letzten Jahre in der pränatalen Diagnostik ist die bessere Identifizierung von Risikoschwangerschaften für die häufigsten Aneuploidien durch die praktische Etablierung des sogenannten Risikoscreening im ersten Schwangerschaftsdrittel. Demgegenüber erscheint der praktische Nutzen der schnellen Methoden zum selektiven Aneuploidieausschluss (FISH, QF-PCR), die zweifelsohne grundsätzlich einen Platz in der Diagnostik haben, gegenwärtig eher begrenzt. Diese Methoden spielen jedoch im Wettbewerb der Laboratorien eine nicht zu unterschätzende Rolle. Der eigentliche Schwerpunkt der kommenden Jahre wird die Einführung von Mikro-Arrays in die Routinediagnostik von Chromosomenanomalien sein. Es ist zu hoffen, dass auch im deutschsprachigen Raum zukünftig die gesetzlichen Voraussetzungen für eine Präimplantationsdiagnostik im frühen Embryonalstadium geschaffen werden. Dies würde zumindest Paaren mit hohem Wiederholungsrisiko für diagnostizierbare genetische Erkrankungen eine Schwangerschaft ermöglichen ohne mit dem ethischen Dilemma eines Schwangerschaftsabbruchs konfrontiert zu werden.
Ethische und biopolitische Probleme der Stammzellforschung
Authors: Schreiber
Published: November 2006

Die Stammzellforschung weckt viele Hoffnungen auf neue Behandlungsoptionen im Bereich der Transplantationsmedizin sowie Zelltherapie für Krankheiten wie Diabetes, Parkinson, Chorea Huntington etc. Probleme im Umfeld dieser Forschung betreffen jedoch nicht nur die Politik, vielmehr müssen sich auch diejenigen der Ethikdebatte stellen, die in diesem Bereich forschend tätig sind. Entsprechend findet seit langem eine äußerst anspruchsvolle Debatte in der Öffentlichkeit über die vielfältigen Problemaspekte dieser biomedizinischen Forschung statt. Trotz der hohen Erwartungen, wird es noch lange dauern, bis sich die neu gewonnenen Erkenntnisse im klinischen Alltag werden umsetzen lassen.
Ethische Aspekte bei Schwangerschaften an der Grenze der kindlichen Lebensfähigkeit
Authors: Berger  , Holzgreve
Published: November 2006

Trotz weiterer Verbesserungen in der perinatologischen Betreuung von Frühgeborenen an der Grenze der kindlichen Lebensfähigkeit sind die Mortalitätsraten für Frühgeborene mit einem Gestationsalter von weniger als 24 vollendeten Schwangerschaftswochen (SSW) in den letzten 10 Jahren hoch geblieben, und die Mehrzahl der überlebenden Kinder zeigen Auffälligkeiten in ihrer psychomotorischen Entwicklung. Ausgelöst durch neue Erkenntnisse über die Prognose dieser Patienten spielen Fragen zum zumutbaren Leiden und zur erreichbaren Lebensqualität in den ethischen Diskussionen um Therapieentscheidungen zunehmend eine zentrale Rolle. Fachgesellschaften in verschiedenen Ländern haben inzwischen ihre Überlegungen dazu in Publikationen zur Betreuung dieser Patienten festgehalten, um ihren in der Entscheidung stehenden Mitgliedern eine Hilfe zu geben. Sämtliche Empfehlungen geben ein Gestationsalter an, unterhalb dessen in der Regel auf den Einsatz intensivmedizinischer Maßnahmen primär verzichtet werden sollte. Diese absolute Interventionsgrenze variiert allerdings erheblich (Deutschland, Japan: < 22 SSW; USA, Kanada und England: < 23 SSW, Schweiz: < 24 SSW, Niederlande: < 25 SSW). Oberhalb dieser Grenzen wird eine Grauzone von 1–2 SSW definiert, innerhalb derer im Sinne einer individualisierten Strategie intensivmedizinische Maßnahmen initiiert werden können («provisional intensive care») und aufgrund engmaschiger Verlaufsbeobachtungen beurteilt wird, ob der fortgesetzte Einsatz solcher Maßnahmen weiterhin gerechtfertigt scheint. Bei Auftreten schwerwiegender Komplikationen besteht die Möglichkeit, den Einsatz lebenserhaltender Maßnahmen zu begrenzen oder zugunsten einer palliativen Betreuung («comfort care») zu sistieren. Jenseits dieser Grauzone wird die intensivmedizinische Betreuung zur Regel. Hier reicht die Interventionsgrenze von 22 SSW (Japan) bis 26 SSW (Niederlande). Die Erfolge der Frühgeborenenmedizin dürfen sich aber sicher nicht alleine an Überlebensraten messen. Berichte über neue Rekorde – ob in der Laienpresse oder der medizinischen Fachliteratur – sind grundsätzlich als problematisch zu werten, da sie einerseits unrealistische Hoffnungen schüren und andererseits dazu führen können, dass falsche Ziele anvisiert werden. Es gilt zu bedenken, dass sich im Schatten jedes publizierten «miracle baby» zahlreiche verstorbene Frühgeborene verbergen, deren (Leidens-)Geschichten anonym bleiben. Die Perinatologie sollte ihre Forschungsbestrebungen auf die Prävention der Frühgeburtlichkeit und die Verbesserung der Langzeitresultate von Frühgeborenen mit einem Gestationsalter von mehr als 23–24 SSW konzentrieren. Ein weiteres Absenken der Grenze der Lebensfähigkeit hat dagegen keine Priorität.
Determination of ice water path in ice‐over‐water cloud systems using combined MODIS and AMSR‐E measurements
Authors: Huang Jianping , Minnis Patrick , Lin Bing , Yi Yuhong , Fan T.‐F. , Sun‐Mack Sunny , Ayers J. K.
Published: November 2006

To provide more accurate ice cloud microphysical properties, the multi‐layered cloud retrieval system (MCRS) is used to retrieve ice water path (IWP) in ice‐over‐water cloud systems globally over oceans using combined instrument data from Aqua. The liquid water path (LWP) of lower‐layer water clouds is estimated from the Advanced Microwave Scanning Radiometer for EOS (AMSR‐E) measurements. The properties of the upper‐level ice clouds are then derived from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements by matching simulated radiances from a two‐cloud‐layer radiative transfer model. The results show that the MCRS can significantly improve the accuracy and reduce the over‐estimation of optical depth and IWP retrievals for ice‐over‐water cloud systems. The mean daytime ice cloud optical depth and IWP for overlapped ice‐over‐water clouds over oceans from Aqua are 7.6 and 146.4 gm−2, respectively, down from the initial single‐layer retrievals of 17.3 and 322.3 gm−2. The mean IWP for actual single‐layer clouds is 128.2 gm−2.
On the coupling of layer instabilities in the nighttime midlatitude ionosphere
Authors: Tsunoda Roland T.
Published: November 2006

There are two plasma‐structuring mechanisms that are known to operate at night in the midlatitude ionosphere, the Perkins instability (Perkins, 1973) in the F region, and the more recently discovered sporadic‐E layer (EsL) instability (Cosgrove and Tsunoda, 2002) in the E region. Both are layer processes, whose coupled response has been shown to be more unstable than either by itself (Cosgrove and Tsunoda, 2004). Derived growth rates, however, were given only in terms of the most unstable mode; exactly how the individual growth rates in the Es and F layers are affected by coupling remains to be shown. To do so, simplified descriptions of the instabilities are derived in this paper to show that the growth rates of both layer instabilities are enhanced by additional vertical drifts produced by polarization electric fields that map between regions along geomagnetic field lines. Key findings are (1) largest enhancement is in the growth rate of F region structure (γPc), (2) γPc is controlled by the EsL instability, and (3) additional positive feedback to the EsL instability occurs because of its dependence on the field‐line‐integrated Pedersen conductivity of the F layer. An important byproduct of this study is the finding that a more consistent interpretation of existing data is possible, if we assume that the coupled system involves a large‐scale, but finite‐sized, Es patch. These new findings seem to explain several puzzling observations that are associated with midlatitude spread F.
Storm time evolution of the outer radiation belt: Transport and losses
Authors: Ukhorskiy A. Y. , Anderson B. J. , Brandt P. C. , Tsyganenko N. A.
Published: November 2006

During geomagnetic storms the magnetic field of the inner magnetosphere exhibits large‐scale variations over timescales from minutes to days. Being mainly controlled by the magnetic field the motion of relativistic electrons of the outer radiation belt can be highly susceptible to its variations. This paper investigates evolution of the outer belt during the 7 September 2002 storm. Evolution of electron phase space density is calculated with the use of a test‐particle simulation in storm time magnetic and electric fields. The results show that storm time intensification of the ring current produces a large impact on the belt. In contrast to the conventional Dst effect the dominant effects are nonadiabatic and lead to profound and irreversible transformations of the belt. The diamagnetic influence of the partial ring current leads to expansion of electron drift orbits such that their paths intersect the magnetopause leading to rapid electron losses. About 2.5 hr after the storm onset most of the electrons outside L = 5 are lost. The partial ring current pressure also leads to an electron trap in the dayside magnetosphere where electrons stay on closed dayside drift orbits for as long as 11 hours. These sequestered electrons are reinjected into the outer belt due to partial recovery of the ring current. The third adiabatic invariant of these electrons exhibits rapid jumps and changes sign. These jumps produce localized peaks in the L*‐profile of electron phase space density which have previously been considered as an observable indication of local electron acceleration.
Timescales of relativistic electron enhancements in the slot region
Authors: Nagai T. , Yukimatu A. S. , Matsuoka A. , Asai K. T. , Green J. C. , Onsager T. G. , Singer H. J.
Published: November 2006

We present two event studies of significant enhancements of relativistic electron flux in the slot region of Earth's radiation belts during storms, using electron measurements from the Akebono spacecraft at high altitudes and NOAA 15, 16, 17, and 18 at low altitudes. These flux enhancements take place during the main phase of storms, and occur rapidly on timescales of less than 60 min. In association with storm time substorms, the magnetic field at geosynchronous altitude becomes highly stretched, intensifies, and then returns to a more dipolar configuration. The flux enhancements in the slot region are likely associated with these large changes in the nightside magnetic field configuration. The observations imply that rapid particle acceleration and/or transport processes operate in the inner (L < 3) magnetosphere in association with large substorms during the main phase of a storm.
Particle‐in‐cell simulations of current shear‐driven instabilities and the generation of broadband ELF fluctuations
Authors: Liu K. , Seyler C. E. , Xu T.
Published: November 2006

Three‐dimensional electromagnetic particle‐in‐cell (PIC) simulations are performed to study the properties of current shear‐driven (CSD) instabilities, which are driven by the free energy stored in the inhomogeneous transverse magnetic field and associated with the transverse gradient of the field‐aligned current. Current shear‐driven instabilities are unstable in both a static field‐aligned current equilibrium and the sheared field‐aligned current sheet embedded in a transversely finite Alfvén wave. The simulation results demonstrate that the electromagnetic fluctuations generated by CSD instabilities have characteristics similar to the broadband ELF (BBELF) fluctuations observed in the topside auroral region and at higher altitudes. It is also shown that CSD instabilities have the capacity to accelerate ions transversely. Comparison of the PIC simulations with the satellite observations and three‐dimensional, two‐fluid MHD simulations supports CSD instabilities as potential candidates for the generation of BBELF fluctuations and the correlated transverse acceleration of ions.
The role of synaptic ion channels in synaptic plasticity
Authors: Voglis Giannis , Tavernarakis Nektarios
Published: November 2006

The nervous system receives a large amount of information about the environment through elaborate sensory routes. Processing and integration of these wide‐ranging inputs often results in long‐term behavioural alterations as a result of past experiences. These relatively permanent changes in behaviour are manifestations of the capacity of the nervous system for learning and memory. At the cellular level, synaptic plasticity is one of the mechanisms underlying this process. Repeated neural activity generates physiological changes in the nervous system that ultimately modulate neuronal communication through synaptic transmission. Recent studies implicate both presynaptic and postsynaptic ion channels in the process of synapse strength modulation. Here, we review the role of synaptic ion channels in learning and memory, and discuss the implications and significance of these findings towards deciphering the molecular biology of learning and memory.
The structure of the Sec complex and the problem of protein translocation
Authors: Robson Alice , Collinson Ian
Published: November 2006

Proteins synthesized in the cytosol either remain there or are localized to a specific membrane and subsequently translocated to another cellular compartment. These extracytosolic proteins have to cross, or be inserted into, a phospholipid bilayer—a process governed by membrane‐bound protein transporters designed to recognize and receive appropriate polypeptides and thread them through the membrane. One such translocation complex, SecY/Sec61, is found in every cell, in either the plasma membrane of bacteria and archaea or the endoplasmic reticulum membrane of eukaryotes. Recent structural findings, combined with previous genetic and biochemical studies, have helped to describe how the passage of proteins through the membrane might occur, but several points of uncertainty remain.
Do orphan G‐protein‐coupled receptors have ligand‐independent functions?
Authors: Levoye Angélique , Dam Julie , Ayoub Mohammed A , Guillaume Jean‐Luc , Jockers Ralf
Published: November 2006

G‐protein‐coupled receptors (GPCRs) are important drug targets and are involved in virtually every biological process. However, there are still more than 140 orphan GPCRs, and deciphering their function remains a priority for fundamental and clinical research. Research on orphan GPCRs has concentrated mainly on the identification of their natural ligands, whereas recent data suggest additional ligand‐independent functions for these receptors. This emerging concept is connected with the observation that orphan GPCRs can heterodimerize with GPCRs that have identified ligands, and by so doing regulate the function of the latter. Pairing orphan GPCRs with their potential heterodimerization partners will have a major impact on our understanding of the extraordinary diversity offered by GPCR heterodimerization and, in addition, will constitute a novel strategy to elucidate the function of orphan receptors that needs to be added to the repertoire of ‘deorphanization’ strategies.
Unusual magnetic and transport properties of oxygen deficient Sr2Fe1−xCoxMoO6−d
Authors: Chang Hong , García-Hernández Mar , Alonso Jose Antonio
Published: November 2006

In the title compounds the oxygen voids have a significant influence over the transport properties, compared with the parent stoichiometric compounds (Sr2FeMoO6 and Sr2CoMoO6) where the oxygen defects have little impact on the crystallographic and magnetic properties. For Sr2FeMoO6−d and Sr2Fe0.95Co0.05MoO6−d, the oxygen voids simply decrease the magnetoresistance (MR) without altering the contours, and for x⩾0.1 at the expense of the decreased low field MR, the oxygen voids enhance MR at high applied field, which is 6%–8% larger than the parent compounds for 0.2⩽x⩽0.7. Remarkably enough, the antiferromagnetic Sr2Fe0.1Co0.9MoO6−d exhibits record negative magnetoresistance ratio MR=((R(H,T)−R(0,T))∕R(0,T))×100% as high as 99%.
Photonic band tuning in two-dimensional photonic crystal slab waveguides by atomic layer deposition
Authors: Graugnard E. , Gaillot D. P. , Dunham S. N. , Neff C. W. , Yamashita T. , Summers C. J.
Published: November 2006

The photonic bands of two-dimensional (2D) triangular lattice photonic crystal Si slab waveguides were statically tuned using low temperature atomic layer deposition (ALD) of TiO2. Angular dependent reflectance measurements of bare and coated devices were well fitted by three-dimensional finite-difference time-domain calculations. The technique not only allows the physics of photonic band effects in 2D photonic crystals to be systematically studied but also demonstrates large static tuning and precise fine-scale control over band frequency and dispersion, with a frequency tuning range of 12% and precision of 0.005% per ALD cycle. Band tuning to achieve zero group velocity is demonstrated.
Room temperature ferromagnetism in Mn-doped γ-Ga2O3 with spinel structure
Authors: Hayashi Hiroyuki , Huang Rong , Ikeno Hidekazu , Oba Fumiyasu , Yoshioka Satoru , Tanaka Isao , Sonoda Saki
Published: November 2006

Mn-doped Ga2O3 (7 cation % of Mn) thin film has been grown on c-cut sapphire substrate using pulsed-laser deposition technique. Electron diffraction analyses by transmission electron microscopy found that the Mn-doped film shows γ phase with spinel structure, which is different from undoped film showing β phase. No secondary phase can be detected. Combination of Mn-L2,3 near edge x-ray absorption experiments with first-principles many-electron calculations unambiguously implies that Mn atoms are located at tetrahedrally coordinated Ga sites with a valence of +2. The doped sample shows ferromagnetism up to 350K.
First stages of the formation of Ni silicide by atom probe tomography
Authors: Hoummada K. , Cadel E. , Mangelinck D. , Perrin-Pellegrino C. , Blavette D. , Deconihout B.
Published: November 2006

Atom probe tomography assisted by femtosecond laser pulses has been performed on a Ni(Pt) film on (100)Si. Two phases with different compositions were found to form during deposition at room temperature: a NiSi layer with a relatively constant thickness of approximately 2nm and a particle of Ni2Si. The shape of the Ni2Si particle is in accordance with nucleation followed by lateral growth formation. This confirms the growth model deduced from calorimetric measurement of silicides and intermetallics and from atom probe tomography studies of the Al∕Co system. A nonuniform redistribution of Pt was also observed.
Critical parameters for the molecular beam epitaxial growth of 1.55μm (Ga,In)(N,As) multiple quantum wells
Authors: Ishikawa Fumitaro , Luna Esperanza , Trampert Achim , Ploog Klaus H.
Published: November 2006

The authors discuss the effect of substrate temperature and As beam equivalent pressure (BEP) on the molecular beam epitaxial growth of (Ga,In)(N,As) multiple quantum wells (MQWs). Transmission electron microscopy studies reveal that a low substrate temperature essentially prevents composition modulations. Secondary ion mass spectrometry results indicate that a low As BEP reduces the incorporation competition of group V elements. The low substrate temperature and low As BEP growth condition leads to (Ga,In)(N,As) MQWs containing more than 4% N preserving good structural and optical properties, and hence demonstrating 1.55μm photoluminescence emission at room temperature.
Sodium chloride sensing by using a near-field microwave microprobe
Authors: Babajanyan Arsen , Kim Jongchul , Kim Songhui , Lee Kiejin , Friedman Barry
Published: November 2006

The authors observed the NaCl concentration of solutions using a near-field microwave microprobe (NFMM). Instead of the usual technique, they take advantage of the noncontact evaluation capabilities of a NFMM. A NFMM with a high Q dielectric resonator allows observation of small variations of the permittivity due to changes in the NaCl concentration. By measuring the reflection coefficient S11, they could observe the concentration of NaCl. The measured signal-to-noise was about 53dB and the minimum detectible signal was about 0.005dB∕(mg∕ml). In order to determine the probe selectivity, they measured a mixture solution of NaCl and glucose.
Periodic corrugation on dynamic fracture surface in brittle bulk metallic glass
Authors: Xi X. K. , Zhao D. Q. , Pan M. X. , Wang W. H. , Wu Y. , Lewandowski J. J.
Published: November 2006

Dynamic crack propagation in a model brittle bulk metallic glass (BMG) is studied. Contrary to other brittle glassy materials, the authors find nanometer scale out-of-plane periodic corrugations along the crack surface of the BMG. The nanoscale periodicity remains nearly constant at different loading rates. An interpretation is presented to explain the evolution and the periodic coalescence of the nanometer scale cavities along the crack surface. The observation sheds light on the origin of dynamic fracture surface roughening in brittle materials and could be generally applicable to brittle materials.
Interface stabilization by Al in GaN and AlN epitaxies on NbB2(0001)
Authors: Aizawa Takashi , Otani Shigeki , Hishita Shunichi
Published: November 2006

Plasma-assisted molecular beam epitaxy of GaN and AlN is investigated on a boron-terminated transition-metal diboride (0001) surface: NbB2(0001). In contrast to metal-terminated ZrB2(0001), GaN does not grow epitaxially on this surface. Instead, a thin hBN layer is formed. On the other hand, AlN does grow epitaxially on this boron-terminated surface. Moreover, only a monolayer of predeposited Al effectively changes the hBN formation into the GaN epitaxial growth. Such a thin Al-related interface species cannot function as a physical buffer layer to relax the lattice stress, but it does give a chemical effect that lowers the nitride-boride interface energy.
Large magnetic entropy changes in the Ni45.4Mn41.5In13.1 ferromagnetic shape memory alloy
Authors: Han Z. D. , Wang D. H. , Zhang C. L. , Tang S. L. , Gu B. X. , Du Y. W.
Published: November 2006

The inverse magnetocaloric effect associated with the martensitic transition in the Ni45.4Mn41.5In13.1 Heusler alloy is reported. A large positive magnetic entropy change of 8J∕kgK under a low magnetic field of 10kOe is found near the martensitic transition temperature. This change originates from the first-order transition from a low-temperature weak-magnetic martensitic phase to a high-temperature ferromagnetic austenitic phase. The large low-field magnetic entropy change indicates a great potential of Ni–Mn–In alloys as working materials for magnetic refrigeration in a wide temperature range.
Simple sequence repeats in organellar genomes of rice: frequency and distribution in genic and intergenic regions
Authors: Rajendrakumar Passoupathy , Biswal Akshaya Kumar , Balachandran Sena M. , Srinivasarao Kommoju , Sundaram Raman M.
Published: November 2006

Motivation: Simple sequence repeats (SSRs) are abundant across genomes. However, the significance of SSRs in organellar genomes of rice has not been completely understood. The availability of organellar genome sequences allows us to understand the organization of SSRs in their genic and intergenic regions.

Results: We have analyzed SSRs in mitochondrial and chloroplast genomes of rice. We identified 2528 SSRs in the mitochondrial genome and average 870 SSRs in the chloroplast genomes. About 8.7% of the mitochondrial and 27.5% of the chloroplast SSRs were observed in the genic region. Dinucleotides were the most abundant repeats in genic and intergenic regions of the mitochondrial genome while mononucleotides were predominant in the chloroplast genomes. The rps and nad gene clusters of mitochondria had the maximum repeats, while the rpo and ndh gene clusters of chloroplast had the maximum repeats. We identified SSRs in both organellar genomes and validated in different cultivars and species.

Contact:  rms_28@rediffmail.com.

Supplementary information: Supplementary Data are available at Bioinformatics online.
GECO–linear visualization for comparative genomics
Authors: Kuenne C. T. , Ghai R. , Chakraborty T. , Hain T.
Published: November 2006

Summary: In order to understand and interpret phylogenetic and functional relationships between multiple prokaryotic species, qualitative and quantitative data must be correlated and displayed. GECO allows linear visualization of multiple genomes using a client/server based approach by dynamically creating .png- or .pdf-formatted images. It is able to display ortholog relations calculated using BLASTCLUST by color coding ortholog representations. Irregularities on the genomic level can be identified by anomalous G/C composition. Thus, this software will enable researchers to detect horizontally transferred genes, pseudogenes and insertions/deletions in related microbial genomes.

Availability:  

Contact:  Carsten.Kuenne@mikrobio.med.uni-giessen.de
Radiation Response of Cultured Human Cells Is Unaffected by Johrei
Authors: Hall Zach , Luu Tri , Moore Dan , Yount Garret
Published: November 2006

Johrei has been credited with healing thousands from radiation wounds after the Hiroshima and Nagasaki bombs in 1945. This alternative medical therapy is becoming increasingly popular in the United States, as are other Energy Medicine modalities that purport to influence a universal healing energy. Human brain cells were cultured and exposed to increasing doses of ionizing radiation. Experienced Johrei practitioners directed healing intentionality toward the cells for 30 min from a distance of 20 cm and the fate of the cells was observed by computerized time‐lapse microscopy. Cell death and cell divisions were tallied every 30 min before, during and after Johrei treatment for a total of 22.5 h. An equal number of control experiments were conducted in which cells were irradiated but did not receive Johrei treatment. Samples were assigned to treatment conditions randomly and data analysis was conducted in a blinded fashion. Radiation exposure decreased the rate of cell division (cell cycle arrest) in a dose‐dependent manner. Division rates were estimated for each 30 min and averaged over 8 independent experiments (4 control and 4 with Johrei treatment) for each of 4 doses of X‐rays (0, 2, 4 and 8 Gy). Because few cell deaths were observed, pooled data from the entire observation period were used to estimate death rates. Analysis of variance did not reveal any significant differences on division rate or death rate between treatment groups. Only radiation dose was statistically significant. We found no indication that the radiation response of cultured cells is affected by Johrei treatment.
Identification of an infectious progenitor for the multiple-copy HERV-K human endogenous retroelements
Authors: Dewannieux Marie , Harper Francis , Richaud Aurélien , Letzelter Claire , Ribet David , Pierron Gérard , Heidmann Thierry
Published: November 2006

Human Endogenous Retroviruses are expected to be the remnants of ancestral infections of primates by active retroviruses that have thereafter been transmitted in a Mendelian fashion. Here, we derived in silico the sequence of the putative ancestral “progenitor” element of one of the most recently amplified family—the HERV-K family—and constructed it. This element, Phoenix, produces viral particles that disclose all of the structural and functional properties of a bona-fide retrovirus, can infect mammalian, including human, cells, and integrate with the exact signature of the presently found endogenous HERV-K progeny. We also show that this element amplifies via an extracellular pathway involving reinfection, at variance with the non-LTR-retrotransposons (LINEs, SINEs) or LTR-retrotransposons, thus recapitulating ex vivo the molecular events responsible for its dissemination in the host genomes. We also show that in vitro recombinations among present-day human HERV-K (also known as ERVK) loci can similarly generate functional HERV-K elements, indicating that human cells still have the potential to produce infectious retroviruses.
Differential Effects of Centrally‐Administered Oestrogen Antagonist ICI‐182,780 on Oestrogen‐Sensitive Functions in the Hypothalamus
Authors: Steyn F. J. , Anderson G. M. , Grattan D. R.
Published: November 2006

Oestrogen actions within the hypothalamus are essential for a range of reproductive functions. In this study, we sought to develop a method for suppressing central oestrogen action without affecting peripheral oestrogenic effects. We administered the oestrogen receptor antagonist ICI‐182,780 (ICI) via crystalline implants into the left lateral ventricle or the arcuate nucleus and measured the effectiveness of this drug on three endpoints known to be regulated by oestrogen: gonadotrophin‐releasing hormone (GnRH) pulse frequency, progesterone receptor expression and the generation of a sustained prolactin surge during late pregnancy. To confirm that central ICI administration had no effect on peripheral actions of oestrogen, we monitored changes in uterine weight. Intracerebroventricular ICI treatment reversed the inhibitory effects of oestrogen on GnRH pulse frequency, as measured by plasma luteinising hormone pulse frequency. No effect on the oestrogenic induction of progesterone receptors within the arcuate nucleus or ventromedial hypothalamus was observed; however, a small yet significant reduction in progesterone receptor expression within dopaminergic neurones in the arcuate nucleus was observed. Intracerebroventricular or direct crystalline ICI administration to the arcuate nucleus did not change the serum prolactin level during late pregnancy. Central administration of ICI did not affect uterine weight, and thus did not have a peripheral effect. These data suggest that central administration of ICI can overcome some actions of oestrogen in the brain, such as GnRH pulse frequency, but does not affect other oestrogen mediated actions, including the induction of progesterone receptors or the antepartum prolactin surge. Thus, it appears that there is a differential sensitivity to the inhibition of central oestrogen actions by ICI.
Development and characterization of eight new microsatellite markers for the haremic sandperch, Parapercis cylindrica (family Pinguipedidae)
Authors: SMITH‐KEUNE C. , JERRY D. R. , EVANS B. S. , MCCORMICK M. I. , MUNDAY P. L. , JONES G. P.
Published: November 2006

Eight di‐, tri‐ and tetranucleotide microsatellite markers were developed for the haremic sandperch Parapercis cylindrica using a linker‐ligated, magnetic bead enrichment protocol. Screening of at least 17 individuals showed these markers to be polymorphic with observed heterozygosity ranging from 0.381 to 1.000 (mean = 0.742) and the numbers of alleles ranging from three to 18. The average polymorphic information content for these eight loci was 0.723. These markers may be used for parentage studies aimed at exploring the complex mating strategies employed by this haremic coral reef fish and will be valuable for population genetic studies.
Eight polymorphic microsatellite markers developed in the green leaf bug, Lygus lucorum Meyer‐Dür (Hemiptera: Miridae)
Authors: LIU YU‐DI , YANG ZHONG‐CHENG , WU KONG‐MING
Published: November 2006

We developed eight polymorphic microsatellite markers for the green leaf bug, Lygus lucorum Meyer‐Dür. The number of observed alleles per locus in 48 individuals ranged from three to 13, whereas the observed and expected heterozygosities ranged from 0.133 to 0.810 and from 0.236 to 0.886, respectively. Cross‐species amplifications were conducted both within and between generas, and the amplification results indicated that these primers enriched for L. lucorum Meyer‐Dür are species‐specific.
The one-dimensional hydrogen atom revisited
Authors: Palma Guillermo , Raff Ulrich
Published: November 2006

The one-dimensional Schrödinger hydrogen atom is an interesting mathematical and physical problem for the study of bound states, eigenfunctions, and quantum-degeneracy issues. This one-dimensional physical system has given rise to some intriguing controversy for more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier-transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found that the complete Balmer energy spectrum is obtained together with an odd-parity set of eigenfunctions. Closed-form solutions in both coordinate and momentum spaces were obtained. No twofold degeneracy was observed as predicted by the degeneracy theorem in one dimension, though it does not necessarily have to hold for potentials with singularities. No ground state with infinite energy exists since the corresponding eigenfunction does not satisfy the Schrödinger equation at the origin.PACS Nos.: 03.65.Ge, 03.65.–w
Sum rules for an atomic hyperfine structure in a magnetic field
Authors: Karshenboim Savely G
Published: November 2006

The sum rules for the energy levels of a hyperfine multiplet in a constant uniform magnetic field are presented. It is found that for any value of the electron angular moment and the nuclear spin there are certain linear combinations of energy levels that do not depend on the magnetic field and can be used to determine the unperturbed hyperfine-structure separation in the presence of a perturbing magnetic field. It is also demonstrated that there are other linear combinations that are linear with the external magnetic field and hence can be used to determine bound values of the electron and nuclear magnetic moments. The accuracy of the approximation within which the result is valid is also discussed.PACS Nos.: 32.10.Fn, 32.60.+i1
Quantizing a relativistic free-particle on the light front: some subtle aspects
Authors: Suzuki A T , Sales J HO , Zambrano G ER
Published: November 2006

We use the light-front “machinery” to study the behavior of a relativistic free particle and obtain the quantum commutation relations from the classical Poisson brackets. We argue that their usual projection onto the light-front coordinates from the covariant commutation relations show that there is an inconsistency in the expected correlation between canonically conjugate variables “time” x+ and “energy” p–. This incompatibility between canonical conjugate variables in the light front is discussed in the context of Poisson brackets and a suggestion is made on how to avoid it. PACS Nos.: 12.39.Ki, 14.40.Cs, 13.40.Gp
Transformation of the integral using Hylleraas coordinates in N-dimensions
Authors: Mukhopadhyay Soma , Chatterjee Ashok
Published: November 2006

The integral ∫ F(r, r′, |r–r′|) dr dr′ where r and r′ are N-dimensional position vectors can be transformed into a simple three-dimensional integral using Hylleraas coordinates. A simple derivation of this result is presented. PACS Nos.: 31.15.–p; 31.15.Ja; 03.65.–w
Electrons in a box: Thomas–Fermi solution
Authors: Sañudo J , Pacheco A F
Published: November 2006

The Thomas-Fermi density distribution of N electrons located inside a box is obtained. This system models some aspects of the structure of the new artificial atoms or quantum dots fabricated using present semiconductor technology. The three-dimensional solutions are obtained by means of a perturbative series, using a convenient dimensionless parameter characteristic of the size of the box and the electron number. The explicit analytic form for the first two terms of the series is derived. PACS No.: 71.10.Ca
MICROSCOPIC MODELING THE DEMOGRAPHIC CHANGES
Authors: BOŃKOWSKA KATARZYNA , SZYMCZAK SZYMON , CEBRAT STANISŁAW
Published: November 2006

We have adapted the Penna ageing model to simulate the profound changes in the age structures of populations caused by the better life style, medical care and decrease in birth rate. In Poland, after the political transformations in the last decade of the twentieth century, the increase in the expected lifespan has been accompanied by very deep decrease in birthrate, much below the minimum necessary for keeping the constant size of the population. Our microscopic model describes the changes in the age structure which have already happened and predicts the future, assuming that our attitudes in respect to life style and social relations will not change.
SOCIOECONOPHYSICS: OPINION DYNAMICS FOR NUMBER OF TRANSACTIONS AND PRICE, A TRADER BASED MODEL
Authors: TUNCAY ÇAĞLAR
Published: November 2006

Involving effects of media, opinion leader and other agents on the opinion of individuals of market society, a trader based model is developed and utilized to simulate price via supply and demand. Pronounced effects are considered with several weights and some personal differences between traders are taken into account. Resulting time series and probabilty distribution function involving a power law for price come out similar to the real ones.
TRUTH SEEKERS IN OPINION DYNAMICS MODELS
Authors: MALARZ KRZYSZTOF
Published: November 2006

We modify the model of Deffuant et al. to distinguish true opinion among others in the fashion of Hegselmann and Krause (). The basic features of both models modified to account for truth seekers are qualitatively the same.
ATTENUATION OF SPURIOUS OSCILLATIONS IN THE NUMERICAL CAPTURE OF SHOCK WAVES
Authors: PORTES D. , RODRIGUES H. , DUARTE S. B.
Published: November 2006

Artificial viscosity is often expressed as a superposition of linear and quadratic terms in the first derivative of the velocity field. In trying to find a continuous solution for the hydrodynamic equations, we propose an alternative one-term artificial viscosity which is a linear form of the derivative of the specific volume. It is shown that this artificial viscosity is able to capture the profile of the steady plane shock wave, largely removing the non-physical oscillations originated by the artificial viscosity of von Neumann and Richtmyer. Analytical and numerical calculations for one-dimensional shock using both artificial viscosities are compared.
SOME BASIC CRYPTOGRAPHIC REQUIREMENTS FOR CHAOS-BASED CRYPTOSYSTEMS
Authors: ALVAREZ GONZALO , LI SHUJUN
Published: November 2006

In recent years, a large amount of work on chaos-based cryptosystems have been published. However, many of the proposed schemes fail to explain or do not possess a number of features that are fundamentally important to all kind of cryptosystems. As a result, many proposed systems are difficult to implement in practice with a reasonable degree of security. Likewise, they are seldom accompanied by a thorough security analysis. Consequently, it is difficult for other researchers and end users to evaluate their security and performance. This work is intended to provide a common framework of basic guidelines that, if followed, could benefit every new cryptosystem. The suggested guidelines address three main issues: implementation, key management and security analysis, aiming at assisting designers of new cryptosystems to present their work in a more systematic and rigorous way to fulfill some basic cryptographic requirements. Meanwhile, several recommendations are made regarding some practical aspects of analog chaos-based secure communications, such as channel noise, limited bandwith and attenuation.
A COMPARATIVE STUDY OF INFORMATION CRITERIA FOR MODEL SELECTION
Authors: NAKAMURA TOMOMICHI , JUDD KEVIN , MEES ALISTAIR I. , SMALL MICHAEL
Published: November 2006

To build good models, we need to know the appropriate model size. To handle this problem, a variety of information criteria have already been proposed, each with a different background. In this paper, we consider the problem of model selection and investigate the performance of a number of proposed information criteria and whether the assumption to obtain the formulae that fitting errors are normally distributed hold or not in some conditions (different data points and noise levels). The results show that although the application of information criteria prevents over-fitting and under-fitting in most cases, there are cases where we cannot avoid even involving many data points and low noise levels in ideal situations. The results also show that the distribution of the fitting errors is not always normally distributed, although the observational noise is Gaussian, which contradicts an assumption of the information criteria.