bluuebunny/crossref_metadata_2025 huggingface dataset:
Compensatory growth responses to defoliation and light availability in two native Mexican woody plant species
Authors: Ballina-Gómez Horacio Salomón , Iriarte-Vivar Silvia , Orellana Roger , Santiago Louis S.
Published: January 2010

Defoliation, often caused by herbivory, is a common cause of biomass loss for plants that can affect current and future growth and reproduction. There are three models that predict contrasting compensatory growth responses of plants to herbivory and resource availability: (1) Growth rate model, (2) Compensatory continuum hypothesis and (3) Limiting resource model. The predictions of these three models were tested on the tree Brosimum alicastrum and the liana Vitis tiliifolia. Seedlings were subjected to three levels of experimental defoliation (0%, 50% and 90% leaf removal) along a light resource gradient (1%, 9% and 65% of full sun). In both species, defoliation significantly increased leaf production rate and relative growth rate of leaf area, but not of biomass. Net assimilation rate was the strongest driver of biomass growth in both species, but leaf area ratio and specific leaf area were also important in B. alicastrum. Compensatory responses of leaf area growth in B. alicastrum were significantly greater in higher than lower light availability, consistent with the compensatory continuum hypothesis predictions, but in contrast to the growth rate model predictions. The limiting resource model offered an explanation for all possible experimental outcomes by directly considering the effects of environmental differences in resource availability.
Growth and home range size of the gracile mouse opossum Gracilinanus microtarsus (Marsupialia: Didelphidae) in Brazilian cerrado
Authors: Fernandes Fernanda Rodrigues , Cruz Leonardo Dominici , Martins Eduardo Guimarães , dos Reis Sérgio Furtado
Published: January 2010

Differences in growth patterns between the sexes of the gracile mouse opossum Gracilinanus microtarsus and the consequences for home range size were investigated in a savanna habitat (cerrado) of south-eastern Brazil. A total of 51 juvenile individuals of Gracilinanus microtarsus was monitored using capture–mark–recapture from November 2005 to August 2006. The increase in body mass of gracile mouse opossums was described using the Gompertz growth model. Male gracile mouse opossums grew faster than females (dimorphic ratio of 1.5). Home range size, estimated with the minimum convex polygon method, was positively related to body mass. Model selection using Akaike's Information Criterion (AICc) and incorporating body mass, sex and season as independent variables showed that the best-supported model describing variance in home range sizes included only body mass. Our data suggest that a greater body mass gain in juvenile males is probably the proximate cause of sexual dimorphism in adult gracile mouse opossums and that energetic needs required for growth have a greater influence in home range size.
Spatial patterns of tree recruitment in East African tropical forests that have lost their vertebrate seed dispersers
Authors: Babweteera Fred , Brown Nick
Published: January 2010

The direct removal of adult trees by logging affects tree recruitment in tropical rain forests. However, secondary effects of logging, such as loss of vertebrate seed dispersers may also affect tree recruitment. We studied the recruitment and spatial distribution of five tree species namely Balanites wilsoniana, Celtis zenkeri, Chrysophyllum albidum, Cordia millenii and Ricinodendron heudelotii in Kibale, Budongo and Mabira Forests in Uganda. These forests have been subjected to varying degrees of disturbance leading to changes in their vertebrate seed dispersers. Vertebrate frugivores of the five tree species were identified. Three 1-ha plots were established around adult trees of the same five species in each forest and the distance from the juveniles to the nearest adult conspecific was measured to generate a recruitment curve. Frugivore visitation rates were high in the less disturbed Budongo and Kibale (2.2 and 1.6 individuals h−1 respectively) compared with the highly disturbed Mabira (0.9 individuals h−1). In the frugivore-impoverished forest, 70–90% of juveniles established beneath adult conspecifics, whereas in the less-disturbed forests juveniles were established up to 80 m from adult conspecifics. Shade-tolerant species capable of recruiting beneath adult conspecifics appeared to maintain their populations without dispersal. Consequently, disturbances leading to significant loss of vertebrates may alter tree recruitment and spatial distribution with consequences for long-term population viability of shade-intolerant tropical trees.
Detection of three distinct genetic lineages in methicillin-resistantStaphylococcus aureus(MRSA) isolates from animals and veterinary personnel
Authors: ABBOTT Y. , LEONARD F. C. , MARKEY B. K.
Published: January 2010

This study involved the phenotypic and molecular characterization of a population of methicillin-resistantStaphylococcus aureusisolates from animals and from veterinary personnel in Ireland. Isolates from 77 animals (dogs,n=44; cats,n=4; horses,n=29) and from 28 veterinary personnel were characterized using their antimicrobial resistance profiles and pulsed-field gel electrophoresis patterns. In addition, a representative number of these isolates (n=52) were further analysed usingspa-typing techniques. The results obtained identified the presence of three distinct clonal complexes, CC5, CC8 and CC22, in both animal and human isolates. Two of these clonal complexes, CC8 and CC22, respectively, have been previously described in animals in Ireland but the presence of the third complex CC5 is a novel finding. The significance of this development, in relation to human and animal healthcare, is discussed.
Relapse and reacquisition of rectal colonization by vancomycin-resistantEnterococcus faeciumafter decolonization
Authors: LEE W. G. , PARK I. J. , JIN H. Y. , PARK M. H.
Published: January 2010

To better understand the epidemiology of colonization of vancomycin-resistant enterococci (VRE), we performed an 8-year retrospective study of all hospitalized patients with recurrent VRE colonization after they were documented as being clear of VRE and compared the primary colonization isolates and recolonization isolates by pulsed-field gel electrophoresis and Tn1546typing. Review of the medical records of all patients showed that of the 15 patients with recurrent colonization, six continued to be hospitalized on the same floor. Five were discharged home and then readmitted. Four were moved to another floor. Patients who remained on the same floor were recolonized with a strain that was indistinguishable from the original colonizing strain. Patients who were moved or were discharged hadde novoVRE colonization with strains distinct from the original colonizing strain.
Prevalence of livestock-associated MRSA in broiler flocks and risk factors for slaughterhouse personnel in The Netherlands
Authors: MULDERS M. N. , HAENEN A. P. J. , GEENEN P. L. , VESSEUR P. C. , POLDERVAART E. S. , BOSCH T. , HUIJSDENS X. W. , HENGEVELD P. D. , DAM-DEISZ W. D. C. , GRAAT E. A. M. , MEVIUS D. , VOSS A. , VAN DE GIESSEN A. W.
Published: January 2010

To determine methicillin-resistantStaphylococcus aureus(MRSA) carriage in poultry and slaughterhouse personnel, 40 Dutch broiler flocks, in six slaughterhouses and 466 personnel were sampled. Of the employees, 26 were positive (5·6%), indicating a higher risk of exposure when compared to the general Dutch population (0·1%). This risk was significantly higher for personnel having contact with live animals (5·2%) – especially hanging broilers on the slaughterline (20·0%) – than for all other personnel (1·9%). Conventional electric stunning conferred a significantly higher risk of MRSA carriage for employees than CO2stunning (9·7%vs. 2·0%). A total of 405 broilers were sampled upon their arrival at the slaughterhouse, of which 6·9% were positive. These broilers originated from 40 Dutch slaughter flocks of which 35·0% were positive. MRSA contamination in the different compartments of slaughterhouses increased during the production day, from 8% to 35%. Of the 119 MRSA isolates, predominantly livestock-associated MRSA ST398 was found, although 27·7% belonged to ST9 (spatype t1430). There is an increased risk of MRSA carriage in personnel working at broiler slaughterhouses, particularly those having contact with live animals.
Breeding population dynamics and habitat transition of Saunders's GullLarus saundersiin Yancheng National Nature Reserve, China
Authors: JIANG H. X. , HOU Y. Q. , CHU G. Z. , QIAN F. W. , WANG H. , ZHANG G. G. , ZHENG G. M.
Published: January 2010

Saunders's GullLarus saundersiis a breeding endemic of Common SeepweedSuaeda glaucahabitats on the east coast of China and south-west coast of South Korea. Much of this habitat has been lost and degraded due to human land use and expansion of the introduced Smooth CordgrassSpartina alterniflora. Yancheng National Nature Reserve (NNR) is one of three breeding and wintering areas in China. We used satellite images from 1992 to 2007 and visual interpretation combined with ground truthing to classify the land cover and quantify changes in land use and land cover (LULC) in areas of Yancheng NNR used by Saunders's Gull. The Common Seepweed habitat, in which this species nests, decreased in area by 79.1% (27,358 ha) over 15 years, predominantly as a result of conversion to aquaculture ponds (18,929 ha), and is now centred in the south-east of Yancheng NNR. The total population size of Saunders's Gull was maintained at over 900 individuals from 1999 to 2006 in Yancheng NNR, but was only 575 in 2007, and the number of breeding sites decreased from eight in 1992 and 1994 to a single site in 2000–2006 and two sites in 2007. From 1999 to 2007, the breeding population in the core area of Yancheng NNR accounted for 94.93% of the total population, and its nest-site spatial turnover rate was 0.84 ± 0.08 (n= 7 years), but it tended to decrease by about 40% in 2007 because of degradation of the Common Seepweed community. The conversion of Common Seepweed habitats to other habitat types and expansion of introduced Smooth Cordgrass were the major and direct reasons for the loss and degradation of breeding habitats of Saunders's Gull. Smooth Cordgrass habitats increased in area by 321.9% (11,057 ha) during this period and centred on the east, gradually occupying the mudflats, except the beach from Liangduo River to the south of Yancheng NNR, where potential breeding sites for the Saunders's Gull could be located. We discuss the implications of our results for the conservation this species and management of its habitats.
Death and Memory on the Home Front: Second World War Commemoration in the South Hams, Devon
Authors: Walls Samuel , Williams Howard
Published: January 2010

In this article we explore a pair of distinctive and associated Second World War monuments on Slapton Sands in the South Hams district of Devon, UK. The Slapton Sands Evacuation Memorial was erected in 1945 by the US armed forces to commemorate the sacrifice of local people who evacuated their homes ahead of battle training in preparation for D-Day. Meanwhile, the Torcross Tank Memorial was built in 1984 under the initiative of a local man to commemorate those US servicemen who lost their lives during the battle training in the Exercise Tiger tragedy. The historical context, form, materiality, biography and location of each monument are appraised and their relationship with each other is discussed. The article argues that from the 1940s to the present day, the monuments have evolved as sacrificial sites and serve to both commemorate the events they describe and define the identities of local people through their reuse of places and material culture.
Metacognitive unawareness correlates with executive function impairment after severe traumatic brain injury
Authors: CIURLI PAOLA , BIVONA UMBERTO , BARBA CARMEN , ONDER GRAZIANO , SILVESTRO DANIELA , AZICNUDA EVA , RIGON JESSICA , FORMISANO RITA
Published: January 2010

The aim of this study was to evaluate clinical, neuropsychological, and functional differences between severe traumatic brain injury (TBI) outpatients with good and/or heightened metacognitive self-awareness (SA) and those with impaired metacognitive SA, assessed by the Patient Competency Rating Scale (PCRS). Fifty-two outpatients were recruited from a neurorehabilitation hospital based on the following inclusion criteria: 1) age ≥ 15 years; 2) diagnosis of severe TBI; 3) availability of neuroimaging data; 4) post-traumatic amnesia resolution; 5) provision of informed consent. Measures: A neuropsychological battery was used to evaluate attention, memory and executive functions. SA was assessed by the PCRS, which was administered to patients and close family members. Patients were divided into two groups representing those with and without SA. Patients with poor SA had more problems than those with good SA in some components of the executive system, as indicated by the high percentage ofperseverativeerrors and responses they made on the Wisconsin Card Sorting Test. Moreover, a decrease in metacognitive SA correlated significantly with time to follow commands (TFC). This study suggests the importance of integrating an overall assessment of cognitive functions with a specific evaluation of SA to treat self-awareness and executive functions together during the rehabilitation process. (JINS, 2010,16, 360–368.)
Expression, purification and identification of gibberellin-induced cysteine-rich protein ofGymanadenia conopsea
Authors: Yuan Liu , Guo-Quan Meng , Jian-Ping Zhou , Teng Zhang , Juan Feng , Zheng-long Ren
Published: January 2010

Primers bearing restriction enzyme sites forEcoR I andHind III were designed according to the known partial cDNA sequence for gibberellin-induced cysteine-rich protein and were then used to amplify the full-length open reading frame (ORF) and signal peptide-truncated fragment of thegcgasagene. Two fragments with lengths 319 and 238 bp were obtained and were further cloned into plasmid pET-32(a). Following transformation intoEscherichia coliBL21(DE3), the fusion proteins were observed to appear at ~26.0 and 25.2 kDa after induction from 1 mmol/l isopropyl-beta-D-thiogalactopyronoside (IPTG). The results of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and transmission electron microscopy (TEM) of an ultra-thin section revealed that the presence of signal peptide gave rise to the formation of an inclusion body located in the periplasmic space; however, the absence of signal peptide greatly enhanced the solubility of the target protein. The expressed soluble protein was further purified by Ni2+-NTA affinity chromatography and gel filtration methods.
Isolation, mapping and application of a repetitive DNA sequence in wheat (Triticum aestivum) A and B genomes
Authors: Zi-Xian Zeng , Zu-Jun Yang , Cheng Liu , Li-Jun Hu , Zheng-Long Ren
Published: January 2010

Simple sequence repeat (SSR) analysis was performed on fiveSecalespecies, fourTriticumspecies and a Triticale line Fenzhi-1 using 102 pairs of microsatellite primers. A 387-bp specific DNA fragment FZ387 (GenBank accession no. EF179137) was obtained from the Triticale Fenzhi-1 with primer Xgwm614, without amplification inSecale. NCBI BLAST revealed that this FZ387 sequence had 94% and 95% similarity to part of the Gypsy Ty3-LTR retrotransposonFatimainTriticum monoccocum(AY485644) andTriticum turgidum(AY494981), respectively. A pair of specific polymerase chain reaction (PCR) primers, FaF and FaR, was designed based on the conserved region of this FZ387 sequence. The amplification of primer pair Xgwm614F and FaR revealed that a specific 350-bp band (designation as A350) was obtained from the species containing A chromosomes. Furthermore, PCR on Langdon Chinese Spring substitution lines was performed, and the results found that this segment was located on both long and short arms of all A chromosomes. However, the amplification of primer pair FaF and Xgwm614R gave rise to a specific DNA band of about 350 bp (designated AB350) from materials containing A and/or B chromosomes. The wild species of wheat and the relatives were amplified using the two pairs of primers, and revealed that only A350 and AB350 were found in Chinese Spring (CS). Sequence comparison and variation of SSR primers binding regions of FZ387 indicated that significant diversity might exist in the internal sequence of thisFatima-like element among triticeae genomes. Meanwhile, both A350 and AB350 can be used as molecular markers for the detection of A and AB genomes.
Pioneers in Optics: Dominique-François-Jean Arago and Augustin-Jean Fresnel
Authors: Davidson Michael W.
Published: January 2010

Dominique-François-Jean Arago, better known simply as François Arago, was born on February 26, 1786, in Eastagel, France. A member of a political family, Arago was provided with a classical education, studying first at Perpignan and then at the École Polytechnique in Paris. In 1809, at the age of 23, Arago became a professor of analytical geometry at the prestigious Paris school and was subsequently made director of the Paris Observatory. Interested in a variety of scientific fields, Arago's greatest contributions were in optics, astronomy, and electromagnetism. A staunch republican, Arago was also active in politics and was a distinguished statesman later in life.
Das sprachliche Arbeitsgedächtnis:Kapazität oder Erfahrung
Authors: Konieczny Lars , Müller Daniel
Published: January 2010

Zusammenfassung. Zur Erklärung interindividueller Unterschiede in der Sprachperformanz bei komplexen Sätzen werden zwei Ansätze diskutiert: Die Theorie der kapazitätsbeschränkten Arbeitsgedächtnisressource ( Just & Carpenter, 1992 ), sowie der auf Elman-Netzen basierende Ansatz von MacDonald und Christiansen (2002) . Letzterer setzt dem Konzept einer in seiner Kapazität eingeschränkten und funktional eigenständigen Arbeitsgedächtnisressource einen integrativen Ansatz von Lernen, Wissen und Verarbeitung entgegen, in dem nicht Kapazität, sondern Erfahrung die zentrale Rolle spielt. Aus ihrem Ansatz ergeben sich interessante Vorhersagen für die Verarbeitung lokaler syntaktischer Kohärenzen – lokal wohlgeformter, jedoch global ausgeschlossener Phrasen oder Sätze. Wir präsentieren Ergebnisse, die die Annahme eines Sequenzlern- und Verarbeitungsansatzes, wie er durch Elman-Netze beschrieben wird, unterstützen. Auf der Basis der Befunde diskutieren wir die Gültigkeit von Arbeitsgedächtnis-basierten Ansätzen im Vergleich zu Netzwerkansätzen, und legen eine Reinterpretation von interindividuellen Unterschieden in einer vermeintlichen Arbeitgedächtniskapazität als solche der lingustischen Erfahrung und Übung nahe.
Subjektive Krankheitskonzepte bei depressiven Störungen
Authors: Horn Andrea B. , Kneisler Lena , Schuster Hendrik , Traue Harald C.
Published: January 2010

Zusammenfassung. Depressive Störungen sind ein weit verbreitetes und oft chronisches Gesundheitsproblem mit erheblichem Leiden des Individuums und hohen Gesundheitskosten. Die subjektiven Wahrnehmungen einer solchen Erkrankung korrelieren mit deren Bewältigung. Dies kann insbesondere für depressive Störungen angenommen werden, da bei Depressionen die dysfunktionalen kognitiven Bewertungsprozesse sowohl ätiologisch relevant sind als auch die Krankheitsbewältigung ungünstig beeinflussen. Diese Studie hat zum Ziel, Zusammenhänge zwischen Dimensionen der Krankheitskonzepte von Patientinnen und Patienten, der depressiven Symptomatik und positivem Affekt zu untersuchen. Dazu wurden 60 Patientinnen und Patienten einer stationären psychosomatischen Rehabilitationsmaßnahme sowohl im Quer- als auch im Längsschnitt bis zur dreimonatigen Katamnese nach Entlassung befragt. Die Studienteilnehmer wurden weiterhin randomisiert einer Expressiven Schreib- oder einer Kontrollbedingung zugeteilt, um die Effekte dieser Minimalintervention als adjunkte Maßnahme zu untersuchen. Die Ergebnisse zeigen, dass die Wahrnehmung des zeitlichen Verlaufs und des Schwergrads der Depression sowie die emotionalen Repräsentationen der eigenen Erkrankung mit vermehrten depressiven Symptomen assoziiert sind. Im Längsschnitt zeigt sich, dass die Ausprägung kontrollbezogener subjektiver Krankheitskonzepte mit unterschiedlichen Verläufen der depressiven Symptomatik und des Wohlbefindens über einen Zeitraum von 3 Monaten nach Beendigung des stationären Aufenthalts im Zusammenhang stehen. Die subjektiv erlebte Kohärenz des Krankheitskonzepts war nur mit dem Wohlbefinden, aber nicht mit Depression verbunden. Expressives Schreiben konnte in dieser kleinen Gruppe zusätzlich zum stationären Aufenthalt zwar keine signifikanten Verbesserungen erzielen, jedoch zeigt sich, dass Personen mit einer stark ausgeprägten Neigung zu emotionalen Repräsentationen tendenziell mehr vom Schreiben profitieren und dass sich dieser Effekt über die Zeit zu verstärken scheint.
Scale interaction between tropical instability waves and low‐frequency oceanic flows
Authors: Kug Jong‐Seong , Ham Yoo‐Geun , Jin Fei‐Fei , Kang In‐Sik
Published: January 2010

Tropical instability waves (TIWs), prevailing in the tropical Pacific and Atlantic Oceans, interact with the low‐frequency oceanic flow. It is known that TIWs act as negative feedback to ENSO through a thermal process. In this study, we examine the dynamical eddy feedback of TIWs. We show that in terms of physical processes, the dynamical TIW feedback is very similar to the atmospheric synoptic eddy feedback in the extratropics. For example, the mean seasonal eddy vorticity flux of TIWs can be largely explained by the left‐hand rule, which states that eddy vorticity fluxes are predominantly directed toward the left‐hand side of the oceanic flow. Therefore, they act as positive feedback to the low‐frequency oceanic flow. We also show that the positive eddy feedback is obtained from eddy structure changes induced by the low‐frequency flow.
Transcriptional activation of DNA‐dependent protein kinase catalytic subunit gene expression by oestrogen receptor‐α
Authors: Medunjanin Senad , Weinert Sönke , Poitz David , Schmeisser Alexander , Strasser Ruth H , Braun‐Dullaeus Ruediger C
Published: January 2010

The cellular response to DNA double‐strand break (DSB) occurs through an integrated sensing and signalling network that maintains genomic stability. Oestrogen (E2), among its many functions, is known to have a positive effect on global genomic DNA repair; however, the mechanism by which it functions is unclear. A central enzyme involved in DNA DSB repair in mammalian cells is the DNA‐dependent protein kinase (DNA‐PK). Here, we show that E2 enhances DNA‐PK catalytic subunit (DNA‐PKcs) promoter activity with subsequent transcriptional and translational upregulation of DNA‐PKcs in a breast cancer cell line. We identify two potential E2 receptor‐α (ERα)‐binding sites in a region upstream from the DNA‐PKcs initiation site. By using small interfering RNA and the specific E2 receptor antagonist ICI 182,780, we demonstrate that ERα knockdown reduces E2‐induced upregulation of DNA‐PKcs expression and activity in breast carcinoma cells. E2‐induced DNA‐PK transactivation results in an increased ability of the cells to repair DNA DSB. This previously unknown mechanism of DNA‐PK regulation sheds new light on tumour biology and reveals new possibilities for the prevention and therapy of E2‐sensitive proliferative diseases.
Bias stress voltage dependence for fast and slow traps resulting in negative bias temperature instability
Authors: Mee J. K. , Devine R. A. B.
Published: January 2010

We have studied the bias stressing voltage dependence of the negative bias temperature instability (NBTI) in p-channel field effect transistors with nominal SiON/HfSiON gate stacks. Measurements were made at the temperature of 448 K. Three different methods were used to extract device parameters such as the NBTI induced threshold voltage shifts ΔVth. One of the methods provided access to all of the NBTI induced trapped charge (both fast and slow relaxing) while the other two methods necessarily determined only the slow trap component. Assuming a model of the form ΔVth=Atα, where t is the bias stressing time, we determine that both A and α are bias voltage dependent for the data from all three extraction methods. Furthermore, slow and slow plus fast trap values were significantly different, suggesting that a unique set of A and α values cannot be used to describe all the traps. This result raises concerns about protocols used with NBTI data to determine the reliability lifetime.
Effective viscosity of semidilute suspensions of rigid ellipsoids
Authors: Hsueh C. H. , Wei W. C. J.
Published: January 2010

Hard and refractory particles with various shapes have been added to ceramic materials to enhance creep resistance. Also, many of the particles in food emulsions, magnetic particle suspensions, and other industrial systems may have nonspherical shapes. Hence, it is important to understand the effects of particle shape on the viscosity of suspensions. While the shape of many particles can be approximated as prolate or oblate spheroids, the purpose of the present study is to model the effective viscosity of semidilute suspensions of rigid ellipsoids. Closed-form expressions are obtained; however, their formulations are formidable. For the special cases of rodlike or disklike particles, simple closed-form expressions can be obtained. The present solutions are compared with existing solutions.
Transfer of InP thin films from engineered porous silicon substrates
Authors: Joshi Monali B. , Goorsky Mark S.
Published: January 2010

Engineered composite substrates for thin film layer transfer applications are fabricated by incorporating the techniques of anodic etching, wafer bonding, and hydrogen-induced exfoliation. Silicon substrates (p/p+) are subjected to anodic electrochemical etching in 25% HF electrolyte to create double layer (40%/60% porosity) structures, which provide the means for subsequent mechanical transfer. Indium phosphide (InP) layers are transferred to the porous Si/Si substrate via silicon nitride interlayer bonding and hydrogen exfoliation. After chemical mechanical polishing, the transferred InP layers have a surface roughness of 0.6 nm and high crystalline quality. Metal-organic chemical vapor deposition on the composite substrate shows that residual ion implantation defects present in the InP template layer do not extend into epilayers, and the substrate maintains its high crystalline quality and mechanical integrity. Transfer of the epitaxial layers from the porous silicon handle wafer to a secondary substrate was achieved via fracture along the double porous layer interface, with no impact on the epilayer strain.
Pulsed-laser treatment of solution-grown ZnO nanowires in nitrogen: Enhancing in electrical conduction and field emission
Authors: Chen J. B. , Xu C. J. , She J. C. , Deng S. Z. , Chen Jun , Xu N. S.
Published: January 2010

Pulsed-laser (neodymium doped yttrium aluminum garnet; 1.06 μm in wavelength) treatments were performed on zinc oxide (ZnO) nanowires (NWs) in nitrogen. It results in nitrogen doping of ZnO, mainly with chemical states of N2 at oxygen sites, which is demonstrated by x-ray photoelectron spectroscopy studies. The laser treated ZnO NWs show significant improvement in electrical conduction and field emission. Typically, with the critical treated conditions of peak power 400 W and pulse duration 2 ms, NWs with the highest conductivity of 1.43×10−2 S/cm was obtained. It is one order of magnitude higher than that of the as-prepared NWs (1.20×10−3 S/cm). These NWs show better field electron emission properties. The turn-on field is 2.0 MV/m and a current density of 5.3 mA/cm2 can be obtained at a field of 3.0 MV/m. The underlying mechanisms related to the enhancing effect of conduction and field emission were discussed. The pulsed-laser treatment may be developed toward a technique for application in the study of nanoelectronic devices using NWs.
Perpendicular magnetization behaviors of Co/FeMn/Co multilayers with and without Pt spacer
Authors: Liu Y. , Fu Y. Q. , Liu S. , Jin C. , Li M. H. , Yu G. H.
Published: January 2010

The interfacial effect on the magnetization in the magnetron sputtered Co/FeMn/Co multilayers with Pt spacer layer upon and beneath the FeMn layer, respectively, was investigated. The variation in the magnetization with the thickness of the Co layer strongly depends on the orientation and the rotation of the interfacial spins at the ultrathin limit of the Co layer as well as the FeMn layer, which is determined by the magnetic anisotropy at the ferromagnetic/antiferromagnetic interface. The perpendicular magnetization is considerably enhanced by the FeMn layer either with or without the Pt spacer, and the enhancement is cut down by inserting the Pt spacer at the Co/FeMn interface, whereas nearly not changed by the Pt spacer at the FeMn/Co interface. Although a perpendicular inducing field is applied during the deposition, the perpendicular exchange bias is not induced at the Co/FeMn interface unless a 0.4 nm Pt spacer is inserted, indicating that the interfacial uncompensated spins could hardly be pinned into the hard axis.
An interchangeable-cathode vacuum arc plasma source
Authors: Olson David K. , Peterson Bryan G. , Hart Grant W.
Published: January 2010

A simplified vacuum arc design [based on metal vapor vacuum arc (MeVVA) concepts] is employed as a plasma source for a study of a B7e non-neutral plasma. The design includes a mechanism for interchanging the cathode source. Testing of the plasma source showed that it is capable of producing on the order of 1012 charges at confinable energies using a boron-carbide disk as the cathode target. The design is simplified from typical designs for lower energy and lower density applications by using only the trigger spark rather than the full vacuum arc in high current ion beam designs. The interchangeability of the cathode design gives the source the ability to replace only the source sample, simplifying use of radioactive materials in the plasma source. The sample can also be replaced with a completely different conductive material. The design can be easily modified for use in other plasma confinement or full MeVVA applications.
Terahertz heterodyne detection with silicon field-effect transistors
Authors: Glaab Diana , Boppel Sebastian , Lisauskas Alvydas , Pfeiffer Ullrich , Öjefors Erik , Roskos Hartmut G.
Published: January 2010

We report on the detection of electromagnetic radiation at 0.65 THz by silicon field-effect transistors operated in heterodyne mode. Aiming at terahertz imaging with numerous pixels in a focal-plane array, we explore the improvement of the dynamic range achieved over power detection when the local-oscillator (LO) power is distributed quasioptically onto all detectors. These consist of resonantly antenna-coupled complementary metal-oxide-semiconductor transistors with a gate length of 0.25 μm, and each has an integrated voltage amplifier. With a LO power of 2 μW per detector, the noise-equivalent power amounts to 8 fW/Hz, leading to an estimated improvement of the dynamic range by 29 dB.
Nanoconfined ionic liquids under electric fields
Authors: Xie Guoxin , Luo Jianbin , Guo Dan , Liu Shuhai
Published: January 2010

The effect of external electric fields (EEFs) on ionic liquid films confined within a nanogap has been investigated by measuring the film thickness with the thin film interferometry and calculating the effective viscosity. Experimental results indicated that the film thickness of ionic liquids could be increased obviously by the application of EEFs with strengths weaker than the electric interactions between cationic head groups and anions. The effect of EEFs on the confined ionic liquid film with a shorter alkyl side chain is more noticeable. It is thought that the charged anions and headgroups of the cations are structured near electrified walls to form ordered layers and short alkyl side chains at the interfaces are aligned along the EEF direction due to induced dipoles.
Room temperature study of the optical switching of a spin crossover compound inside its thermal hysteresis loop
Authors: Gallé G. , Deldicque D. , Degert J. , Forestier Th. , Létard J.-F. , Freysz E.
Published: January 2010

We have studied the low-spin to high spin state phase transition induced by a single or a sequence of nanosecond laser pulses within the thermal hysteresis loop of the [Fe(NH2-trz)3](NO3)2-H2O spin crossover compound. We demonstrate that the final state that is photoinduced can be finely controlled by changing the central wavelength and the energy of the laser pulses. A simple model accounts for the observed phenomena and paves the way for the practical applications to optical data storage at room temperature of spin state transition compounds.
Low-voltage transparent electric-double-layer ZnO-based thin-film transistors for portable transparent electronics
Authors: Lu Aixia , Sun Jia , Jiang Jie , Wan Qing
Published: January 2010

Room-temperature deposited 8.0 μm-thick mesoporous SiO2 dielectric shows a huge electric double layer (EDL) gate specific capacitance (4.16 μF/cm2). Battery drivable low-voltage (1.5 V) transparent EDL thin-film transistors (TFTs) with Al-doped ZnO nanocrystal channel layer gated by such dielectric are fabricated at room-temperature. The TFTs exhibit high-performance n-type transistor characteristics with a high field-effect mobility of 14.9 cm2/V s. The current on/off ratio and subthreshold gate voltage swing are estimated to be 2×106 and 82 mV/decade, respectively. Our results demonstrate that mesoporous SiO2 dielectrics with EDL effect are very promising for battery-powered portable transparent macroelectronics on temperature-sensitive substrates.
The effect of hydrogen bonding on the diffusion of water in n-alkanes and n-alcohols measured with a novel single microdroplet method
Authors: Su Jonathan T. , Duncan P. Brent , Momaya Amit , Jutila Arimatti , Needham David
Published: January 2010

While the Stokes–Einstein (SE) equation predicts that the diffusion coefficient of a solute will be inversely proportional to the viscosity of the solvent, this relation is commonly known to fail for solutes, which are the same size or smaller than the solvent. Multiple researchers have reported that for small solutes, the diffusion coefficient is inversely proportional to the viscosity to a fractional power, and that solutes actually diffuse faster than SE predicts. For other solvent systems, attractive solute-solvent interactions, such as hydrogen bonding, are known to retard the diffusion of a solute. Some researchers have interpreted the slower diffusion due to hydrogen bonding as resulting from the effective diffusion of a larger complex of a solute and solvent molecules. We have developed and used a novel micropipette technique, which can form and hold a single microdroplet of water while it dissolves in a diffusion controlled environment into the solvent. This method has been used to examine the diffusion of water in both n-alkanes and n-alcohols. It was found that the polar solute water, diffusing in a solvent with which it cannot hydrogen bond, closely resembles small nonpolar solutes such as xenon and krypton diffusing in n-alkanes, with diffusion coefficients ranging from 12.5×10−5 cm2/s for water in n-pentane to 1.15×10−5 cm2/s for water in hexadecane. Diffusion coefficients were found to be inversely proportional to viscosity to a fractional power, and diffusion coefficients were faster than SE predicts. For water diffusing in a solvent (n-alcohols) with which it can hydrogen bond, diffusion coefficient values ranged from 1.75×10−5 cm2/s in n-methanol to 0.364×10−5 cm2/s in n-octanol, and diffusion was slower than an alkane of corresponding viscosity. We find no evidence for solute-solvent complex diffusion. Rather, it is possible that the small solute water may be retarded by relatively longer residence times (compared to non-H-bonding solvents) as it moves through the liquid.
Protection by organic ions against DNA damage induced by low energy electrons
Authors: Dumont A. , Zheng Y. , Hunting D. , Sanche L.
Published: January 2010

It is well known that electrons below 15 eV induce strand breaks in DNA essentially via the formation of transient anions which decay by dissociative electron attachment (DEA) or into dissociative electronics states. The present article reports the results of a study on the influence of organic ions on this mechanism. tris and EDTA are incorporated at various concentrations within DNA films of different thicknesses. The amino group of tris molecules and the carboxylic acid function of ethylenediamine tetra-acetic acid (EDTA) molecules together can be taken as simple model for the amino acids components of proteins, such as histones, which are intimately associated with the DNA of eukaryotic cells. The yield of single strand breaks induced by 10 eV electrons is found to decrease dramatically as a function of the number of organic ions/nucleotide. As few as 2 organic ions/nucleotide are sufficient to decrease the yield of single strand breaks by 70%. This effect is partly explained by an increase in multiple inelastic electrons scattering with film thickness but changes in the resonance parameters can also contribute to DNA protection. This can occur if the electron captures cross section and the lifetime of the transient anions (i.e., core-excited resonances) formed at 10 eV are reduced by the presence of organic ions within the grooves of DNA. Moreover, it is proposed that the tris molecules may participate in the repair of DNA anions [such as G(-H)−] induced by DEA on DNA bases.
A large gap of radio frequency dielectric barrier atmospheric pressure glow discharge
Authors: Li B. , Chen Q. , Liu Z. W.
Published: January 2010

A large gap was acquired between electrodes (up to 5.5 mm) of Ar atmospheric pressure glow discharge in radio frequency dielectric barrier discharge (rf-DBD). The discharge of Ar plasma was characterized by I-V curve and Lissajous plot, and the effective power of the discharge was calculated based on the measured Lissajous plot and found to be higher than 90% of the input power. To gain a thorough understanding of the mechanism, the rf-DBD with a single dielectric barrier layer operating in γ mode glow discharge of N2 plasma was diagnosed in spatial resolution through optical emission spectroscopy. It was concluded that secondary electron emission might be responsible for the sustainable glow discharge in the large gap rf-DBD plasma.
The electrostatic coupling of longitudinal optical phonon and plasmon in wurtzite InN thin films
Authors: Chang Y.-M. , Liou S. C. , Chen C. H. , Lee H.-M. , Gwo S.
Published: January 2010

We utilize coherent longitudinal optical phonon as an optical nanoprobe to investigate the plasmonic behavior of wurtzite c-plane InN thin films. The transition from the three-dimensional electron gas in InN bulk toward the two-dimensional electron gas in InN thin film is revealed via measuring the coupling strength of coherent A1(LO) phonon and plasmon coupling mode. The coupling strength diminishes as the film thickness reduces and finally vanishes at 3±1 nm. This phenomenon is ascribed to the detuning of the intersubband plasmon frequency above the A1(LO) frequency, which is originated from the electronic quantum confinement in InN thin films.
Photodissociation of ozone in the Hartley band: Potential energy surfaces, nonadiabatic couplings, and singlet/triplet branching ratio
Authors: Schinke R. , McBane G. C.
Published: January 2010

The lowest five A1′ states of ozone, involved in the photodissociation with UV light, are analyzed on the basis of multireference configuration interaction electronic structure calculations with emphasis on the various avoided crossings in different regions of coordinate space. Global diabatic potential energy surfaces are constructed for the lowest four states termed X, A, B, and R. In addition, the off-diagonal potentials that couple the initially excited state B with states R and A are constructed to reflect results from additional electronic structure calculations, including the calculation of nonadiabatic coupling matrix elements. The A/X and A/R couplings are also considered, although in a less ambitious manner. The photodissociation dynamics are studied by means of trajectory surface hopping (TSH) calculations with the branching ratio between the singlet, O(D1)+O2(Δ1g), and triplet, O(P3)+O2(Σ3g−), channels being the main focus. The semiclassical branching ratio agrees well with quantum mechanical results except for wavelengths close to the threshold of the singlet channel. The calculated O(D1) quantum yield is approximately 0.90–0.95 across the main part of the Hartley band, in good agreement with experimental data. TSH calculations including all four states show that transitions B→A are relatively unimportant and subsequent transitions A→X/R to the triplet channel are negligible.
Universal correction for the Becke–Johnson exchange potential
Authors: Räsänen E. , Pittalis S. , Proetto C. R.
Published: January 2010

The Becke–Johnson exchange potential [A. D. Becke and E. R. Johnson, J. Chem. Phys. 124, 221101 (2006)] has been successfully used in electronic structure calculations within density-functional theory. However, in its original form, the potential may dramatically fail in systems with non-Coulombic external potentials, or in the presence of external magnetic or electric fields. Here, we provide a system-independent correction to the Becke–Johnson approximation by (i) enforcing its gauge-invariance and (ii) making it exact for any single-electron system. The resulting approximation is then better designed to deal with current-carrying states and recovers the correct asymptotic behavior for systems with any number of electrons. Tests of the resulting corrected exchange potential show very good results for a hydrogen chain in an electric field and for a four-electron harmonium in a magnetic field.
Ties That Bind: Governmentality, the State, and Asylum in Contemporary Ireland
Authors: Conlon Deirdre
Published: January 2010

Coinciding with the so-called ‘Celtic Tiger’ boom of the 1990s, Ireland experienced a momentous shift in long-standing patterns of migration, with significant in-migration and an unprecedented change in population dynamics. Asylum seekers form a small and noteworthy group within the population in association with several recent legislative changes. In 2003 a previously granted guarantee of residency rights for so-called ‘non-national’ migrant parents whose children were born in Ireland was withdrawn; subsequently, in 2004 voters endorsed a referendum doing away with the Irish Constitution's provision for birthright citizenship. With this, many asylum seekers and their children who were born in Ireland were excluded from the possibility of establishing intimate ties within society and to the state. This social context forms the backdrop for examining the intersections between governmentality and the intimate ties between populations and nation-state. Drawing on recent attention to Foucault's lectures on Security, Territory, Population, three specifics themes are elaborated; these are: (i) government as a continuum of overlapping apparatuses; (ii) intersections between sovereign territory and population; and (iii) the question of the state in Foucault's work. These themes are elucidated with reference to housing policies, living conditions, and newsprint discourses that prevailed upon women asylum seekers in particular prior to Ireland's 2004 citizenship referendum. The associated unraveling and rearrangement of governmental practices and rejigging of the Irish State highlights some of the ways intimacy and population are tangled together as populations are produced.
Sexual Tensions in Modernizing Singapore: The Postcolonial and the Intimate
Authors: Oswin Natalie
Published: January 2010

During a 2007 reform of Singapore's Penal Code, Prime Minister Lee Hsien Loong rejected calls by gay and lesbian activists for the removal of a colonial-era statute that prohibits ‘gross indecency’ between two men. This paper critically responds to the perpetuation of this illiberal sexual politics by exploring heteronormativity in the city-state as a colonial trace. It takes a postcolonial queer approach that combines insights from work on the globalization of sexuality, histories of colonialism, and postcolonial development geographies to interrogate the sedimentation of heteronormativity in Singapore over its late-colonial and early-postcolonial periods. Emphasis is placed on the role of colonized elites in transforming an entrepot of single male migrant workers into a nation of nuclear families. By attending to the contingent materialities of colonial governance through an examination of the intimate politics advanced by local colonial actors, the legacy of heteronormativity in Singapore is revealed to be about much more than heterosexuality and homosexuality. As such, it is argued that an approach that goes beyond sexuality per se to disrupt the progress narrative on which heteronormativity in Singapore relies might therefore be a useful way to challenge the narrow imagination of intimate possibilities.
Long-term presence and movement patterns of juvenile bull sharks, Carcharhinus leucas, in an estuarine river system
Authors: Heupel Michelle R. , Yeiser Beau G. , Collins Angela B. , Ortega Lori , Simpfendorfer Colin A.
Published: January 2010

Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthropogenic changes to coastal habitats. To address this, patterns of movement of 67 juvenile bull sharks (Carcharhinus leucas) were examined in the Caloosahatchee River between 2003 and 2006 using an array of 25 acoustic receivers. Individuals were monitored for periods of 1–460 days with most present for periods of weeks to months. Individuals utilised the entire monitored section of the river (~27 km) and also moved upriver beyond the extent of the acoustic array. Daily activity spaces of individuals ranged from 0 to 14 km with most <5 km. Monthly mean home ranges were 0.9–5.6 km and although home-range sizes were consistent through time, location of individuals within the river changed through time. Individuals moved upstream during the day and downstream at night and this pattern persisted across years. Based on data collected from depth transmitters in 2006, individuals swam closer to the surface at night and remained in deeper water during the day, suggesting further diurnal patterns in habitat use. Long-term consistent use of this habitat by young C. leucas suggests this population is highly dependent on the Caloosahatchee River as a nursery area.
The influence of sex and maturity on the diet, mouth morphology and dentition of the Port Jackson shark, Heterodontus portusjacksoni
Authors: Powter David Mark , Gladstone William , Platell Margaret
Published: January 2010

Dietary studies are essential for an understanding of elasmobranch ecology and their role in marine ecosystems. The diet, head morphology and dentition of Heterodontus portusjacksoni, an abundant, epibenthic shark in the coastal waters of temperate eastern Australia, were examined in 2004–2005. The stomach contents of the juvenile, subadult and adult stages of 136 males and 100 females were examined. Diets were broad (32 prey taxa), but dominated by molluscs, teleosts and cephalopods. Analyses of stomach contents data demonstrated that diet differed significantly by ontogenetic stage, but not by sex. Juveniles and subadults consumed mainly benthic infauna and epifauna, with subadults ingesting greater amounts of diogenid crustaceans, and adult diets dominated by demersal/pelagic prey. Trophic level differed ontogenetically, from secondary consumers as juveniles and subadults to tertiary consumers as adults. The mainly tricuspidate juvenile dentition changed with maturity to a greater proportion of large molariform distal teeth, whereas the snout and jaw lengthened and broadened. Adult males retained a greater proportion of anterior S-family teeth than females, which was most likely related to copulation. The ontogenetic variation in dietary composition, facilitated by differences in dentition and mouth morphology, demonstrated that dietary resources were partitioned ontogenetically.