bluuebunny/crossref_metadata_2025 huggingface dataset:
User preferences in open and distance language learning: what are the options for multimedia?
Authors: Hagen Stephen
Published: December 2008

The Open University, having just completed its first 25 years, finds itself at an electronic crossroads. In one direction the electronic superhighway and satellite communication stretch forth into the stratosphere of future time. In another, straight ahead, is the well-trodden path of mixed-media open learning, tried, tested and refined over many years. To what extent is it possible to surf on the first with route maps from the second? Are learners at home willing or well-enough equipped to consider scaling new horizons via CD-ROMs, or on-line learning technologies in place of print, audio-cassette and video? What new methodology, if any, needs to be developed to assist this transition?
Using the Robert Electronique as a language learning resource
Authors: Glencross Michael
Published: December 2008

The Robert Electronique is the CD-ROM version of the nine volume Grand Robert, roughly the French equivalent of the OED. This article outlines a project to produce some learning materials using this lexical database. It describes various types of exercises ranging from the semantic to the stylistic. Most of the exercises can be completed on screen within a wordprocessing application and can be done by a student working independently. The activities exploit as far as possible features specific to the CD-ROM version of the dictionary.
Persönliche Ziele im Studium
Authors: Brunstein Joachim C. , Dargel Anja , Glaser Cornelia , Schmitt Clemens H. , Spörer Nadine
Published: December 2008

Auf der Grundlage eines teleonomischen Modells des subjektiven Wohlbefindens ( Brunstein, Schultheiss & Maier, 1999 ) entwickelten wir ein Zieleffektivitätstraining, das dazu diente, im Kontext des Universitätsstudiums (a) die Bindung von Studierenden an persönliche Studienziele zu vertiefen und (b) die Planung zugehöriger Handlungsschritte zu konkretisieren. Studie 1, an der 72 Studienanfänger teilnahmen, ergab, dass das vollständige Interventionsprogramm zu einer erhöhten Effektivität bei der Umsetzung persönlicher Studienziele führte und darüber vermittelt die akademische und soziale Anpassung im Verlauf des ersten Semesters verbesserte. Studie 2, an der 88 Studierende im zweiten Studienjahr teilnahmen, zeigte, dass beide Interventionskomponenten (Zielbindung und Zielplanung) einen eigenständigen Beitrag zur Förderung der Effektivität beim Erreichen selbst gesetzter Zielstandards leisteten und miteinander kombiniert die Studienzufriedenheit deutlich erhöhten.
Der Simulierte Klassenraum
Authors: Südkamp Anna , Möller Jens , Pohlmann Britta
Published: December 2008

In zwei experimentellen Studien wurde als Aspekt der diagnostischen Kompetenz die Genauigkeit von Leistungsbeurteilungen hinsichtlich eines globalen Abweichungsmaßes und ihrer Rang-, Niveau-, und Differenzierungskomponente analysiert. Zu diesem Zweck wird der Simulierte Klassenraum (SKR) genutzt, die Computersimulation einer Unterrichtssituation, in der Anwender die Rolle eines Lehrers übernehmen und mit simulierten Schülern interagieren. In zwei unterschiedlich gestalteten Unterrichtsstunden können Lehrer Fragen an die Schüler richten, deren Antworten entgegennehmen und anschließend deren (experimentell manipulierte) Leistung beurteilen. In beiden Studien zeigte sich, dass die Probanden (Studie 1: N = 24 Lehramtsstudierende; Studie 2: N = 20 Lehramtsstudierende) eine relativ genaue Rangfolge der Schülerleistungen bilden können, während das Leistungsniveau insgesamt überschätzt und die Streuung der Leistungen unterschätzt wurde.
Statistical evaluation and choice of soil water retention models
Authors: Lennartz Franz , Müller Hans‐Otfried , Nollau Volker , Schmitz Gerd H. , El‐Shehawy Shaban A.
Published: December 2008

This paper presents the results of statistical investigations for the evaluation of soil water retention models (SWRMs). We employed three different methods developed for model selection in the field of nonlinear regression, namely, simulation studies, analysis of nonlinearity measures, and resampling strategies such as cross validation and bootstrap methods. Using these methods together with small data sets, we evaluated the performance of three exemplarily chosen types of SWRMs with respect to their parameter properties and the reliability of model predictions. The resulting rankings of models show that the favorable models are characterized by few parameters with an almost linear estimation behavior and close to symmetric distributions. To further demonstrate the potential of the statistical methods in the field of model selection, a modification of the four‐parameter van Genuchten model is proposed which shows significantly improved and robust statistical properties.
Treatment of input uncertainty in hydrologic modeling: Doing hydrology backward with Markov chain Monte Carlo simulation
Authors: Vrugt Jasper A. , ter Braak Cajo J. F. , Clark Martyn P. , Hyman James M. , Robinson Bruce A.
Published: December 2008

There is increasing consensus in the hydrologic literature that an appropriate framework for streamflow forecasting and simulation should include explicit recognition of forcing and parameter and model structural error. This paper presents a novel Markov chain Monte Carlo (MCMC) sampler, entitled differential evolution adaptive Metropolis (DREAM), that is especially designed to efficiently estimate the posterior probability density function of hydrologic model parameters in complex, high‐dimensional sampling problems. This MCMC scheme adaptively updates the scale and orientation of the proposal distribution during sampling and maintains detailed balance and ergodicity. It is then demonstrated how DREAM can be used to analyze forcing data error during watershed model calibration using a five‐parameter rainfall‐runoff model with streamflow data from two different catchments. Explicit treatment of precipitation error during hydrologic model calibration not only results in prediction uncertainty bounds that are more appropriate but also significantly alters the posterior distribution of the watershed model parameters. This has significant implications for regionalization studies. The approach also provides important new ways to estimate areal average watershed precipitation, information that is of utmost importance for testing hydrologic theory, diagnosing structural errors in models, and appropriately benchmarking rainfall measurement devices.
Influence of epoch time selection on the results of superposed epoch analysis using ACE and MPA data
Authors: Ilie Raluca , Liemohn Michael W. , Thomsen Michelle F. , Borovsky Joseph E. , Zhang Jichun
Published: December 2008

The influence of the reference time selection when conducting a superposed epoch analysis is examined for intense geomagnetic storms at solar maximum. The events were selected according to the minimum pressure‐corrected Dst, Dst*, being less than −100 nT. Solar wind data from ACE are used, along with near‐Earth data from the magnetospheric plasma analyzer (MPA) instruments on the Los Alamos National Laboratory–operated geosynchronous spacecraft. Numerous choices for the zero epoch time are used, ranging from the storm sudden commencement (SSC), the peak of the ring current enhancement (minimum Dst* slope), to the time of the storm peak (minimum Dst* value). When doing superposed epoch analysis (SEA), the choice of the time stamp can be very important; for different choices, different storm characteristics are evident in the averaged data. In the superposed ACE data we find that when using the SSC as a time reference, the SSC‐related jump in solar wind parameters is very well defined, but near the storm peak, Bz does not apparently follow the well‐known criteria for intense storms (Bz ≤ −10 nT for more than 3 h), even though this criterion is met by most of the individual storms selected for this study. When the zero epoch time is chosen near the storm peak, the jump in solar wind parameters is less distinct (and eventually lost), but the criterion for Bz is met. Regarding the MPA data, there are certain parameters that require the choice of a specific epoch time in order to produce a systematic behavior in the SEA analysis and others that are less sensitive to this choice of epoch time, since they appear to be less distinct in their temporal and spatial location. For instance, the nightside and morningside hot‐ion density and temperature are main phase traits, and a zero epoch time near the peak of the ring current enhancement is required to make these features distinct.
Nightside flow enhancement associated with solar wind dynamic pressure driven reconnection
Authors: Boudouridis A. , Lyons L. R. , Zesta E. , Ruohoniemi J. M. , Lummerzheim D.
Published: December 2008

Over the past few years the prominent role of solar wind dynamic pressure in enhancing dayside and nightside reconnection and driving enhanced ionospheric convection has been documented by both ground and spaceborn instruments. Super Dual Auroral Radar Network (SuperDARN) observations show that solar wind pressure fronts induce significantly enhanced ionospheric convection in the dayside ionosphere. In parallel, Defense Meteorological Satellite Program (DMSP) precipitating particle measurements and POLAR Ultra‐Violet Imager (UVI) images have demonstrated that sudden solar wind pressure increases also significantly reduce the size of the polar cap, especially on the nightside, suggesting an enhancement of magnetotail reconnection. MHD models of the interaction of the magnetosphere with solar wind pressure fronts have reproduced the enhancement of dayside reconnection but have failed so far to account for the observed closing of the polar cap on the nightside and the suggested magnetotail reconnection increase. We use SuperDARN measurements of ionospheric convection within the nightside polar ionosphere, including near the magnetic separatrix, to evaluate the strength of the observed nightside reconnection enhancement after an abrupt increase in solar wind dynamic pressure on 6 November 2000 and compare it with similar observations on the dayside. We show that an enhancement of nightside convection occurs after a sudden increase in solar wind pressure, delayed by about 40 min compared with the observed dayside convection enhancement. The nightside enhanced flows are observed crossing the open‐closed boundary determined by POLAR UVI data, indicating an enhancement of tail reconnection that is possibly due to the pressure increase and is, in addition to the tail reconnection, associated with the more immediate closing of the polar cap.
Precipitation regime of Dronning Maud Land, Antarctica, derived from Antarctic Mesoscale Prediction System (AMPS) archive data
Authors: Schlosser E. , Duda M. G. , Powers J. G. , Manning K. W.
Published: December 2008

The precipitation regime of Dronning Maud Land (DML), Antarctica, was studied using Antarctic Mesoscale Prediction System (AMPS) archive data. Precipitation is the most important component of the mass balance of the Antarctic ice sheet. Precipitation studies of DML are particularly important because two deep ice core drilling sites, Kohnen Station and Dome Fuji, are located in this region. For the correct interpretation of the ice core properties a thorough understanding of the precipitation regime is necessary. We used the high‐resolution AMPS archive data for the years 2001–2006 to investigate the temporal and spatial distribution of precipitation. The results were compared to a recently published mass balance map derived from glaciological data of western DML. The mass balance map and the AMPS mean annual precipitation field show fairly similar patterns, which are mostly related to topography and prevailing wind systems. Precipitation is found to generally decrease from the coast to the inland plateau. Along the escarpment between the low‐altitude coastal areas and the interior plateau, local minima and maxima in precipitation correspond to the leeward and windward sides of topographical ridges. Interannual variability of monthly sums of precipitation is fairly high owing to the influence of cyclone activity on precipitation, which affects not only the coastal regions, but also the interior of the continent more than previously thought.
Quantifying uncertainty in estimates of mineral dust flux: An intercomparison of model performance over the Bodélé Depression, northern Chad
Authors: Todd M. C. , Bou Karam D. , Cavazos C. , Bouet C. , Heinold B. , Baldasano J. M. , Cautenet G. , Koren I. , Perez C. , Solmon F. , Tegen I. , Tulet P. , Washington R. , Zakey A.
Published: December 2008

Mineral dust aerosols play an important role in the climate system. Coupled climate‐aerosol models are an important tool with which to quantify dust fluxes and the associated climate impact. Over the last decade or more, numerous models have been developed, both global and regional, but to date, there have been few attempts to compare the performance of these models. In this paper a comparison of five regional atmospheric models with dust modules is made, in terms of their simulation of meteorology, dust emission and transport. The intercomparison focuses on a 3‐day dust event over the Bodélé depression in northern Chad, the world's single most important dust source. Simulations are compared to satellite data and in situ observations from the Bodélé Dust Experiment (BoDEx 2005). Overall, the models reproduce many of the key features of the meteorology and the large dust plumes that occur over the study domain. However, there is at least an order of magnitude range in model estimates of key quantities including dust concentration, dust burden, dust flux, and aerosol optical thickness. As such, there remains considerable uncertainty in model estimates of the dust cycle and its interaction with climate. This paper discusses the issues associated with partitioning various sources of model uncertainty.
Updated H2SO4‐H2O binary homogeneous nucleation look‐up tables
Authors: Yu Fangqun
Published: December 2008

The calculated rates of H2SO4‐H2O binary homogeneous nucleation (BHN), which is the only nucleation mechanism currently widely used in global aerosol models, are well known to have large uncertainties. Recently, we have reduced the uncertainties in the BHN rates on the basis of a kinetic quasi‐unary nucleation (KQUN) model, by taking into account the measured bonding energetics of H2SO4 monomers with hydrated sulfuric acid dimers and trimers. The uncertainties were further reduced by using two independent measurements to constrain the equilibrium constants for monomer hydration. In this paper, we present updated BHN rate look‐up tables derived from the improved KQUN model which can be used by anyone to obtain the BHN rates under given conditions. The look‐up tables cover a wide range of key parameters that can be found in the atmosphere and laboratory studies, and their usage significantly reduces the computational costs of the BHN rate calculations, which is critical for multidimensional modeling. The look‐up tables can also be used by those involved in experiments and field measurements to quickly assess the likeliness of BHN. For quick application, one can obtain the BHN rates and properties of critical clusters by browsing through the tables. A comparison of results based on the look‐up tables with those from widely used classical BHN model indicates that, in addition to several orders of magnitude difference in nucleation rates, there also exists substantial difference in the predicted numbers of sulfuric acid molecules in the critical clusters and their dependence on key parameters.
Strength of the H2O near‐infrared absorption bands in hydrated minerals: Effects of measurement geometry
Authors: Pommerol Antoine , Schmitt Bernard
Published: December 2008

Quantitative effects of incidence and emergence angles variations on the 1.9‐ and 3‐μm H2O bands are experimentally investigated for two hydrated minerals: smectite and altered volcanic tuff. Near‐infrared bidirectional reflectance spectra are measured with various incidence and emergence angles leading to phase angles varying between 10° and 140°. We observe a decrease of both band strengths when phase angle increases. The relationship between band strength and phase angle depends on both the absorption intensity, i.e., strong or weak band, and the particle size of the material. We compare experimental results with radiative transfer modeling with optical constants of a smectite. Numerical models can reproduce the changes in band strength with incidence and emergence angles if the value of the single particle scattering anisotropy varies over the absorption band. We attribute this wavelength‐dependent scattering effect to enhanced surface scattering within the absorption bands compared to volume scattering outside the bands. Relative variations of band strength induced by measurement geometry variations can reach tens of percent at high phase angle. Therefore these effects have to be taken into account when mapping spectral parameters on a planetary surface or comparing spectral parameters between two surfaces if measurement geometries are subject to large variations.
Active and zymogen forms of granzyme B are constitutively released from cytotoxic lymphocytes in the absence of target cell engagement
Authors: Prakash Monica D , Bird Catherina H , Bird Phillip I
Published: December 2008

Granzyme B (GrB) plays a well‐established intracellular role in cytotoxic lymphocyte (CL)‐mediated killing of abnormal cells; however, emerging evidence suggests that it participates in extracellular matrix remodeling and target cell destruction through anoikis. As these processes require the release of GrB from the CL into the extracellular environment, we examined the secretion of GrB from natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). We found that a proportion of GrB is constitutively secreted by both CTLs and NK cells in the absence of target cell engagement. In NK cells, the protease is primarily released in an active form through secretory granules. By contrast, T lymphocytes primarily secrete inactive GrB zymogen, bypassing the granules. The release of GrB through two routes from unconjugated CLs suggests that it functions outside the cell and may contribute to pathology in cases of immune dysregulation, such as familial hemophagocytic lymphohistiocytosis (FHL). Our findings also predict the existence of an extracellular activator of GrB.
Antizyme 3 inhibits polyamine uptake and ornithine decarboxylase (ODC) activity, but does not stimulate ODC degradation
Authors: Snapir Zohar , Keren-Paz Alona , Bercovich Zippi , Kahana Chaim
Published: December 2008

Azs (antizymes) are small polyamine-induced proteins that function as feedback regulators of cellular polyamine homoeostasis. They bind to transient ODC (ornithine decarboxylase) monomeric subunits, resulting in inhibition of ODC activity and targeting ODC to ubiquitin-independent proteasomal degradation. Az3 is a mammalian Az isoform expressed exclusively in testicular germ cells and therefore considered as a potential regulator of polyamines during spermatogenesis. We show here that, unlike Az1 and Az2, which efficiently inhibit ODC activity and stimulate its proteasomal degradation, Az3 poorly inhibits ODC activity and fails to promote ODC degradation. Furthermore, Az3 actually stabilizes ODC, probably by protecting it from the effect of Az1. Its inhibitory effect is revealed only when it is present in excess compared with ODC. All three Azs efficiently inhibit the ubiquitin-dependent degradation of AzI (Az inhibitor) 1 and 2. Az3, similar to Az1 and Az2, efficiently inhibits polyamine uptake. The potential significance of the differential behaviour of Az3 is discussed.
TVP23 interacts genetically with the yeast SNARE VTI1 and functions in retrograde transport from the early endosome to the late Golgi
Authors: Stein Ivar S. , Gottfried Anna , Zimmermann Jana , Fischer von Mollard Gabriele
Published: December 2008

SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor) proteins contribute to specific recognition between transport vesicles and target membranes and are required for fusion of membranes. The SNARE Vti1p is required for several transport steps between late Golgi, endosomes and the vacuole in the yeast Saccharomyces cerevisiae. Here, we identified the late Golgi membrane protein TVP23 as a multicopy suppressor of the growth defect in vti1-2 cells. By contrast, the growth defect in vti1-11 cells was not suppressed by TVP23 overexpression. Deletion of TVP23 aggravated the growth defect in vti1-2 cells. Genetic interactions between TVP23 and vti1-2 were not found in transport from the late Golgi via the late endosome to the vacuole or in transport from the Golgi directly to the vacuole. These results suggest that Tvp23p is not involved in forward transport from the late Golgi. Therefore retrograde traffic to the late Golgi was analysed. vti1-2 cells accumulated GFP (green fluorescent protein)–Snc1p within the cell, indicating that retrograde transport from the early endosome to the late Golgi was defective in these cells. Deletion of TVP23 in vti1-2 cells resulted in a synthetic defect in GFP–Snc1p recycling, whereas tvp23Δ cells had a slight defect. These results indicate that Tvp23p performs a partially redundant function in retrograde transport from the early endosome to the late Golgi. This transport step was unaffected in vti1-11 cells, providing an explanation for the allele-specific multicopy suppression by TVP23.
Copper proteins and ferroxidases in human plasma and that of wild-type and ceruloplasmin knockout mice
Authors: Gray Lawrence W. , Kidane Theodros Z. , Nguyen Anh , Akagi Sheryl , Petrasek Kristina , Chu Yu-Ling , Cabrera Anthony , Kantardjieff Katherine , Mason Andrew Z. , Linder Maria C.
Published: December 2008

In the blood plasma of humans and rats, ceruloplasmin is the major copper-binding protein and ferroxidase, accounting for 70% of the copper present in the plasma, with the rest binding primarily to albumin and a macroglobulin. Systematic studies with fresh plasma were carried out to compare what occurs in the mouse. C57BL6 mice had half as much copper and pPD (p-phenylene diamine) oxidase activity as humans and rats, 20–40% as much ferroxidase activity as humans (determined using three different assays) and less inhibition by azide. Plasma from ceruloplasmin knockout mice had no pPD oxidase activity, but retained >50% ferroxidase activity (which was not as affected by azide). Modelling of mouse ceruloplasmin against the known X-ray structure of human ceruloplasmin indicated subtle but potentially significant changes in the pPD- and azide-binding sites. Purification and in-gel assays after native PAGE confirmed that mouse ceruloplasmin had ferroxidase activity but revealed an additional ferroxidase in ceruloplasmin knockout mouse plasma, which is also seen in size-exclusion chromatography. In the wild-type mouse, the ‘ceruloplasmin’ peak contained ∼55% of the total copper, but ceruloplasmin knockout plasma exposed a major additional peak (180 kDa) which co-eluted with ferroxidase activity. Two other ferroxidases (700 and 2000 Da) were also detected in mouse and human plasma. Mammalian blood thus contains copper components and ferroxidases not reported previously.
Extracellular matrix metalloproteinase inducer (EMMPRIN) is present in smooth muscle cells of human aneurysmal aorta and is induced by angiotensin II in vitro
Authors: Chen Xiao-feng , Wang Jian-an , Hou Jun , Gui Chun , Tang Li-jiang , Chen Xiao-quan , Xie Xiao-jie , Jiang Jian-jun , Cai Ju-fang , Chen Han-song , Lu Hong-sheng , Chen Han
Published: December 2008

The aim of the present study was to determine whether EMMPRIN (extracellular matrix metalloproteinase inducer) is present and is up-regulated in human aneurysmal aortas, and to assess a possible association with AngII (angiotensin II)-induced aneurysm formation. The presence of EMMPRIN was assessed in 41 surgical specimens from patients with a TAA (thoracic aortic aneurysm) (Type A aortic dissection, n=12; Type B aortic dissection, n=7; and TAA without dissection, n=7) or an AAA (abdominal aortic aneurysm, n=15) by immunohistochemistry. EMMPRIN expression in aortic aneurysm tissues was compared with 12 aortas obtained during autopsy (free of any vascular diseases), and scored for both staining intensity and the percentage of vascular cells stained. EMMPRIN protein levels in cultured human aortic SMCs (smooth muscle cells) following stimulation of AngII were analysed by Western blotting. Significant EMMPRIN immunoreactivity was detected in aortic aneurysm lesions from patients with TAAs and AAAs. In the aneurysmal wall, α-actin-positive SMCs were the main source of EMMPRIN. The frequency of EMMPRIN overexpression was significantly higher (P=0.026) in TAAs with dissection (68.4%) than TAAs without dissection (14.3%). AngII stimulation up-regulated the expression of EMMPIRN in cultured human aortic SMCs, which was suppressed by the addition of the AT1R (AngII type 1 receptor) antagonist losartan. In conclusion, the present study is the first to report the expression of EMMPRIN in aortic aneurysmal diseases, and we speculate that EMMPRIN may be important in the pathogenesis of these diseases. Whether these abnormalities are potential therapeutic targets deserve further investigation.
Molecular dynamics study of ripples in graphene nanoribbons on 6H-SiC(0001): Temperature and size effects
Authors: Tang Chao , Meng Lijun , Sun Lizhong , Zhang Kaiwang , Zhong Jianxin
Published: December 2008

Using the classical molecular dynamics and the simulated annealing techniques, we show that monolayer graphene nanoribbons (GNRs) on 6H-SiC(0001) surface form atomic scale rippled structures. From the analysis of atomic configurations, two different types of rippled structures in GNRs can be identified, namely, the periodic rippled structure at room temperature or even at lower temperatures and random ripples at high temperatures. The dependence of microscopic roughness of the ripples on temperature and size are studied through analyzing the covalent bonding inhomogeneities in bond-length and bond-angle distributions. Our results provide atomic-level information about the rippled GNRs on SiC substrate, which is useful not only for understanding the structure and stability of monolayer GNRs but also for future applications of GNRs in nanoelectronics.
Structure, conductivity, and transparency of Ga-doped ZnO thin films arising from thickness contributions
Authors: Liang Shuang , Bi Xiaofang
Published: December 2008

Ga-doped ZnO (GZO) films were deposited on amorphous glass substrates at room temperature by radio frequency magnetron sputtering. It is revealed that the influence of deposition parameters, such as target-substrate distance and deposition time, on the structure and properties of the films arises primarily from the variations in film thickness. For the GZO films with smaller thicknesses (≤385 nm), crystallinity is greatly improved with an increase in thickness, which leads to an increase in Hall mobility and a decrease in electrical resistivity. The carrier concentration is, however, found to exhibit only a slight change with the thickness variations. The relationship of electrical property and microstructure suggests that the resistivity of the films arises mainly from ionic impurity scattering rather than from grain boundary scattering. All the films exhibit a transmittance of over 90% in the visible wavelength range. The band gap of the GZO films is widened with increasing film thickness. In combination with the result that the carrier concentration exhibited a slight dependence on thicknesses, the broadening of the band gap with thicknesses is attributed more to the improved crystallinity than to the Moss–Burstein shift.
Local structures surrounding Zr in nanostructurally stabilized cubic zirconia: Structural origin of phase stability
Authors: Soo Y. L. , Chen P. J. , Huang S. H. , Shiu T. J. , Tsai T. Y. , Chow Y. H. , Lin Y. C. , Weng S. C. , Chang S. L. , Wang G. , Cheung C. L. , Sabirianov R. F. , Mei W. N. , Namavar F. , Haider H. , Garvin K. L. , Lee J. F. , Lee H. Y. , Chu P. P.
Published: December 2008

Local environment surrounding Zr atoms in the thin films of nanocrystalline zirconia (ZrO2) has been investigated by using the extended x-ray absorption fine structure (EXAFS) technique. These films prepared by the ion beam assisted deposition exhibit long-range structural order of cubic phase and high hardness at room temperature without chemical stabilizers. The local structure around Zr probed by EXAFS indicates a cubic Zr sublattice with O atoms located on the nearest tetragonal sites with respect to the Zr central atoms, as well as highly disordered locations. Similar Zr local structure was also found in a ZrO2 nanocrystal sample prepared by a sol-gel method. Variations in local structures due to thermal annealing were observed and analyzed. Most importantly, our x-ray results provide direct experimental evidence for the existence of oxygen vacancies arising from local disorder and distortion of the oxygen sublattice in nanocrystalline ZrO2. These oxygen vacancies are regarded as the essential stabilizing factor for the nanostructurally stabilized cubic zirconia.
Measurement of intense coherent synchrotron radiation at frequencies around 0.1 THz using the compact S-band linac
Authors: Sei Norihiro , Kuroda Ryunosuke , Yasumoto Masato , Toyokawa Hiroyuki , Ogawa Hiroshi , Koike Masaki , Yamada Kawakatsu
Published: December 2008

We measured intense radiation from an electron bunch in a millimeter wave region using the compact S-band linac. The dependence of the radiation on the electron-bunch charge was measured with an rf detector system at frequencies around 0.1 THz and was confirmed to be a coherent synchrotron radiation (CSR). The total power of the horizontally and vertically polarized CSRs, which were extracted through the Z-cut quartz window within 1 ns, was calculated to be about 88 and 30 nJ/pulse, excluding the absorption by the window. The two-dimensional distribution of the vertically polarized CSR was measured at a distance of about 0.7 m from the radiation point. The CSR distribution was comparatively uniform in the horizontal plane. Intense CSR, which was reflected in the vacuum chamber, was extracted with a delay of about 6 ns. This suggests that measurement of temporal structure is needed for CSR applications.
A comparison of the effectiveness of bat detectors and harp traps for surveying bats in an urban landscape
Authors: Hourigan C. L. , Catterall Carla P. , Jones Darryl , Rhodes Martin
Published: December 2008

Obtaining adequate information for informed conservation-management decisions requires effective and cost-efficient survey techniques. We compared the effectiveness of bat detectors and harp traps for surveying bat assemblages within an urban landscape in Brisbane, Australia, with respect to number and composition of species. Nine sites within each of three habitat types (remnant bushland, parkland, and low-density residential – a total of 27 sites) were sampled twice each. The bat detectors recorded 3628 calls, from which 13 taxa were identified. The harp traps captured 17 individuals, from which five taxa were identified. All species captured by harp trap were also detected by bat detector, with the possible exception of N. bifax. Bat detectors recorded significantly more species per site than were captured by harp traps, both overall and within each of the three habitat types. And although a considerable amount of time and expense was required to identify the recorded echolocation calls to species, bat detectors were also the most cost-efficient sampling method. These results collectively show that bat detectors were the most effective and cost-efficient method for surveying the bat assemblage in this urban landscape.
Bait acceptance by house mice: an island field trial
Authors: Wanless Ross M. , Fisher Penny , Cooper John , Parkes John , Ryan Peter G. , Slabber Martin
Published: December 2008

Predation by introduced house mice Mus musculus on islands is one cause of decline in native birds and has deleterious impacts on other ecological aspects. Eradication of rats (Rattus spp.) from islands of up to >10000 ha has been achieved, but for mice scale is still an issue with the largest island cleared being only 710 ha. The feasibility of eradicating mice from larger islands is being considered, and to support these assessments, we undertook a field study on Gough Island (6400 ha) to determine whether all mice would be likely to accept toxic bait. We replicated a toxic bait operation as closely as possible, in timing, probable bait density and distribution, using a bait formulation used commonly in rodent eradication operations. Baits lacked toxin but were coated with the fluorescent dye rhodamine B. Mice trapped in and around the baited areas were inspected under ultraviolet light for fluorescent marking indicative of bait consumption. Of 434 mice, 97% tested positive, including mice trapped on assessment lines up to 90 m from the closest bait. There was no difference in the proportions of unstained mice from assessment lines outside baited sites compared with mice trapped in the core baited sites, suggesting large-scale foraging movements over relatively large distances into the baited sites from surrounding, non-baited habitat. Despite the high bait densities (15.7 kg ha−1 at initial application and 7.9 kg ha−1 at second application), bait consumption rates of ~4 kg ha−1 day−1 occurred after both applications. This was much higher than expected (probably the result of large-scale movements) and meant that all baits were consumed before trapping began. Thus the 13 unstained mice trapped in the core of the baited area may have moved there after bait was consumed. Further trials are required to assess whether all unmarked mice were false negatives (not exposed to bait) or if any were true negatives (rejected bait). A separate experiment found that all 11 mice trapped in a cave had eaten bait applied aboveground around the cave’s entrances, suggesting that caves do not serve as refugia for mice and are thus unlikely to compromise an eradication attempt.
Integrated microfluidic bioprocessor for single-cell gene expression analysis
Authors: Toriello Nicholas M. , Douglas Erik S. , Thaitrong Numrin , Hsiao Sonny C. , Francis Matthew B. , Bertozzi Carolyn R. , Mathies Richard A.
Published: December 2008

An integrated microdevice is developed for the analysis of gene expression in single cells. The system captures a single cell, transcribes and amplifies the mRNA, and quantitatively analyzes the products of interest. The key components of the microdevice include integrated nanoliter metering pumps, a 200-nL RT-PCR reactor with a single-cell capture pad, and an affinity capture matrix for the purification and concentration of products that is coupled to a microfabricated capillary electrophoresis separation channel for product analysis. Efficient microchip integration of these processes enables the sensitive and quantitative examination of gene expression variation at the single-cell level. This microdevice is used to measure siRNA knockdown of the GAPDH gene in individual Jurkat cells. Single-cell measurements suggests the presence of 2 distinct populations of cells with moderate (≈50%) or complete (≈0%) silencing. This stochastic variation in gene expression and silencing within single cells is masked by conventional bulk measurements.
Small G proteins exhibit pattern sensitivity in MAPK activation during the induction of memory and synaptic facilitation in
Aplysia
Authors: Ye Xiaojing , Shobe Justin L. , Sharma Shiv K. , Marina Andreea , Carew Thomas J.
Published: December 2008

Memory formation is highly sensitive to specific patterns of training, but the cellular and molecular mechanisms underlying pattern sensitivity are not well understood. We explored this general question by using
Aplysia californica
as a model system. We examined the regulation of MAPK (ERK1/2) activation by small G proteins in the CNS by using different patterns of analog stimuli that mimic different patterns of behavioral training for memory induction. We first cloned and characterized the
Aplysia
homologs of the small G proteins, Ras and Rap1 (ApRas and ApRap, respectively). We next examined changes in ApRas and ApRap activity that accompany MAPK activation. Last, by delivering recombinant ApRas and ApRap into the CNS, we directly manipulated their activity and examined the resultant MAPK activation. We found that MAPK activation induced by analog training depends on the combined activity of ApRas and ApRap, rather than the individual activity of either one alone. Also, ApRas and ApRap have a complex role in MAPK activation: they can act as activators or inhibitors, depending on the specific pattern of the training. The pattern-sensitive regulation of MAPK by interactive ApRas and ApRap activity that we have identified could contribute to the molecular routing of different downstream effects of spatially localized MAPK required for the induction of specific pattern-sensitive forms of synaptic facilitation and memory.
The nuclear membrane organization of leukotriene synthesis
Authors: Mandal Asim K. , Jones Phillip B. , Bair Angela M. , Christmas Peter , Miller Douglas , Yamin Ting-ting D. , Wisniewski Douglas , Menke John , Evans Jilly F. , Hyman Bradley T. , Bacskai Brian , Chen Mei , Lee David M. , Nikolic Boris , Soberman Roy J.
Published: December 2008

Leukotrienes (LTs) are signaling molecules derived from arachidonic acid that initiate and amplify innate and adaptive immunity. In turn, how their synthesis is organized on the nuclear envelope of myeloid cells in response to extracellular signals is not understood. We define the supramolecular architecture of LT synthesis by identifying the activation-dependent assembly of novel multiprotein complexes on the outer and inner nuclear membranes of mast cells. These complexes are centered on the integral membrane protein 5-Lipoxygenase-Activating Protein, which we identify as a scaffold protein for 5-Lipoxygenase, the initial enzyme of LT synthesis. We also identify these complexes in mouse neutrophils isolated from inflamed joints. Our studies reveal the macromolecular organization of LT synthesis.
A postnatal switch of CELF and MBNL proteins reprograms alternative splicing in the developing heart
Authors: Kalsotra Auinash , Xiao Xinshu , Ward Amanda J. , Castle John C. , Johnson Jason M. , Burge Christopher B. , Cooper Thomas A.
Published: December 2008

From a large-scale screen using splicing microarrays and RT-PCR, we identified 63 alternative splicing (AS) events that are coordinated in 3 distinct temporal patterns during mouse heart development. More than half of these splicing transitions are evolutionarily conserved between mouse and chicken. Computational analysis of the introns flanking these splicing events identified enriched and conserved motifs including binding sites for CUGBP and ETR-3-like factors (CELF), muscleblind-like (MBNL) and Fox proteins. We show that CELF proteins are down-regulated >10-fold during heart development, and MBNL1 protein is concomitantly up-regulated nearly 4-fold. Using transgenic and knockout mice, we show that reproducing the embryonic expression patterns for CUGBP1 and MBNL1 in adult heart induces the embryonic splicing patterns for more than half of the developmentally regulated AS transitions. These findings indicate that CELF and MBNL proteins are determinative for a large subset of splicing transitions that occur during postnatal heart development.
Small-interfering RNAs from natural antisense transcripts derived from a cellulose synthase gene modulate cell wall biosynthesis in barley
Authors: Held Michael A. , Penning Bryan , Brandt Amanda S. , Kessans Sarah A. , Yong Weidong , Scofield Steven R. , Carpita Nicholas C.
Published: December 2008

Small-interfering RNAs (siRNAs) from natural
cis
-antisense pairs derived from the 3′-coding region of the barley (
Hordeum vulgare) CesA6
cellulose synthase gene substantially increase in abundance during leaf elongation. Strand-specific RT-PCR confirmed the presence of an antisense transcript of
HvCesA6
that extends ≥1230 bp from the 3′ end of the
CesA
-coding sequence. The increases in abundance of the
CesA6
antisense transcript and the 21-nt and 24-nt siRNAs derived from the transcript are coincident with the down-regulation of primary wall
CesAs
, several
Csl
genes, and
GT8
glycosyl transferase genes, and are correlated with the reduction in rates of cellulose and (1 → 3),(1 → 4)-β-D-glucan synthesis. Virus induced gene silencing using unique target sequences derived from
HvCesA
genes attenuated expression not only of the
HvCesA6
gene, but also of numerous nontarget
Csls
and the distantly related
GT8
genes
and
reduced the incorporation of D-
14
C-Glc into cellulose and into mixed-linkage (1 → 3),(1 → 4)-β-D-glucans of the developing leaves. Unique target sequences for
CslF
and
CslH
conversely silenced the same genes and lowered rates of cellulose and (1 → 3),(1 → 4)-β-D-glucan synthesis. Our results indicate that the expression of individual members of the
CesA
/
Csl
superfamily and glycosyl transferases share common regulatory control points, and siRNAs from natural
cis
-antisense pairs derived from the
CesA
/
Csl
superfamily could function in this global regulation of cell-wall synthesis.
Alkaline polymer electrolyte fuel cells completely free from noble metal catalysts
Authors: Lu Shanfu , Pan Jing , Huang Aibin , Zhuang Lin , Lu Juntao
Published: December 2008

In recent decades, fuel cell technology has been undergoing revolutionary developments, with fundamental progress being the replacement of electrolyte solutions with polymer electrolytes, making the device more compact in size and higher in power density. Nowadays, acidic polymer electrolytes, typically Nafion, are widely used. Despite great success, fuel cells based on acidic polyelectrolyte still depend heavily on noble metal catalysts, predominantly platinum (Pt), thus increasing the cost and hampering the widespread application of fuel cells. Here, we report a type of polymer electrolyte fuel cells (PEFC) employing a hydroxide ion-conductive polymer, quaternary ammonium polysulphone, as alkaline electrolyte and nonprecious metals, chromium-decorated nickel and silver, as the catalyst for the negative and positive electrodes, respectively. In addition to the development of a high-performance alkaline polymer electrolyte particularly suitable for fuel cells, key progress has been achieved in catalyst tailoring: The surface electronic structure of nickel has been tuned to suppress selectively the surface oxidative passivation with retained activity toward hydrogen oxidation. This report of a H
2
–O
2
PEFC completely free from noble metal catalysts in both the positive and negative electrodes represents an important advancement in the research and development of fuel cells.
Protein kinase A inhibits a consolidated form of memory in
Drosophila
Authors: Horiuchi Junjiro , Yamazaki Daisuke , Naganos Shintaro , Aigaki Toshiro , Saitoe Minoru
Published: December 2008

Increasing activity of the cAMP/protein kinase A (PKA) pathway has often been proposed as an approach to improve memory in various organisms. However, here we demonstrate that single-point mutations, which decrease PKA activity, dramatically improve aversive olfactory memory in
Drosophila
. These mutations do not affect formation of early memory phases or of protein synthesis-dependent long-term memory but do cause a significant increase in a specific consolidated form of memory, anesthesia-resistant memory. Significantly, heterozygotes of null mutations in PKA are sufficient to cause this memory increase. Expressing a PKA transgene in the mushroom bodies, brain structures critical for memory formation in
Drosophila
, reduces memory back to wild-type levels. These results indicate that although PKA is critical for formation of several memory phases, it also functions to inhibit at least one memory phase.
Akt2 overexpression plays a critical role in the establishment of colorectal cancer metastasis
Authors: Rychahou Piotr G. , Kang JungHee , Gulhati Pat , Doan Hung Q. , Chen L. Andy , Xiao Shu-Yuan , Chung Dai H. , Evers B. Mark
Published: December 2008

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. Understanding the distinct genetic and epigenetic changes contributing to the establishment and growth of metastatic lesions is crucial for the development of novel therapeutic strategies. In a search for key regulators of colorectal cancer metastasis establishment, we have found that the serine/threonine kinase Akt2, a known proto-oncogene, is highly expressed in late-stage colorectal cancer and metastatic tumors. Suppression of Akt2 expression in highly metastatic colorectal carcinoma cells inhibits their ability to metastasize in an experimental liver metastasis model. Overexpression of wild-type Akt1 did not restore metastatic potential in cells with downregulated Akt2, thus suggesting non-redundant roles for the individual Akt isoforms. In contrast, Akt2 overexpression in wild-type PTEN expressing SW480 colorectal cancer cells led to the formation of micrometastases; however, loss of PTEN is required for sustained formation of overt metastasis. Finally, we found that the consequence of PTEN loss and Akt2 overexpression function synergistically to promote metastasis. These results support a role for Akt2 overexpression in metastatic colorectal cancer and establish a mechanistic link between Akt2 overexpression and PTEN mutation in metastatic tumor establishment and growth. Taken together, these data suggest that Akt family members have distinct functional roles in tumor progression and that selective targeting of the PI3K/Akt2 pathway may provide a novel treatment strategy for colorectal cancer metastasis.
IL-10 and PD-L1 operate through distinct pathways to suppress T-cell activity during persistent viral infection
Authors: Brooks David G. , Ha Sang-Jun , Elsaesser Heidi , Sharpe Arlene H. , Freeman Gordon J. , Oldstone Michael B. A.
Published: December 2008

Suppression of T-cell responses by host-derived regulatory factors is a key event leading to viral persistence. Antibody blockade of either IL-10 or programmed death-ligand 1 (PD-L1) during viral persistence enhances T-cell function and reduces viral titers. Because blockade of these immunoregulatory networks represents a powerful approach to establish immune control during persistent infection, it is important to determine whether these immunoinhibitory factors act independently or jointly and if combined blockade of these factors further enhances T-cell immunity and viral clearance. Herein, we demonstrate that the IL-10 and PD-L1 immunosuppressive pathways are mechanistically distinct. As a result, simultaneous blockade of IL-10 and PD-L1 was significantly more effective in restoring antiviral T-cell responses than blockade of either alone, and led to substantially enhanced control of an established persistent viral infection. Thus, combinatorial blockade of multiple immune-regulatory molecules may ultimately restore the T-cell responses required to tip the balance from viral persistence to immune-mediated control or elimination of persistent infection.