bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct synthesis of luminescent SiC quantum dots in water by laser ablation
Authors: Zakharko Yu. , Rioux D. , Patskovsky S. , Lysenko V. , Marty O. , Bluet J.‐M. , Meunier M.
Published: July 2011

Direct synthesis of luminescent SiC quantum dots in pure deionized water by laser ablation is reported. A zeta‐potential of –49 mV, higher than for nanoparticles produced by electrochemical etching, suggests a higher colloidal stability of the laser‐produced nanoparticles. IR spectroscopy shows that surface charges related to carboxylate anions ensure long‐term stability of the colloidal solutions based on the as‐prepared SiC quantum dots. Main radiative channel at room temperature corresponds to the recombination of quantumly confined photogenerated charge carriers. Emission from the nanoparticles is mainly centred at 2.75 eV regardless of laser power used for ablation. According to photoluminescence spectra, a partial transformation of the SiC quantum dots from cubic to hexagonal crystalline arrangement is supposed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterisation of polyacetylenes isolated from carrot (Daucus carota) extracts by negative ion tandem mass spectrometry
Authors: Rai Dilip K. , Brunton Nigel P. , Koidis Anastasios , Rawson Ashish , McLoughlin Padraig , Griffiths William J.
Published: July 2011

The potential use of negative electrospray ionisation mass spectrometry (ESI‐MS) in the characterisation of the three polyacetylenes common in carrots (Daucus carota) has been assessed. The MS scans have demonstrated that the polyacetylenes undergo a modest degree of in‐source decomposition in the negative ionisation mode while the positive ionisation mode has shown predominantly sodiated ions and no [M+H]+ ions. Tandem mass spectrometric (MS/MS) studies have shown that the polyacetylenes follow two distinct fragmentation pathways: one that involves cleavage of the C3–C4 bond and the other with cleavage of the C7–C8 bond. The cleavage of the C7–C8 bond generated product ions m/z 105.0 for falcarinol, m/z 105/107.0 for falcarindiol, m/z 147.0/149.1 for falcarindiol‐3‐acetate. In addition to these product ions, the transitions m/z 243.2 → 187.1 (falcarinol), m/z 259.2 → 203.1 (falcarindiol), m/z 301.2 → 255.2/203.1 (falcarindiol‐3‐acetate), mostly from the C3–C4 bond cleavage, can form the basis of multiple reaction monitoring (MRM)‐quantitative methods which are poorly represented in the literature. The 'MS3' experimental data confirmed a less pronounced homolytic cleavage site between the C11–C12 bond in the falcarinol‐type polacetylenes. The optimised liquid chromatography (LC)/MS conditions have achieved a baseline chromatographic separation of the three polyacetylenes investigated within 40 min total run‐time. Copyright © 2011 John Wiley & Sons, Ltd.
Measuring long‐chain acyl‐coenzyme A concentrations and enrichment using liquid chromatography/tandem mass spectrometry with selected reaction monitoring
Authors: Blachnio‐Zabielska Agnieszka U. , Koutsari Christina , Jensen Michael D.
Published: July 2011

Long‐chain acyl‐coenzymes A (acyl‐CoAs) (LCACoA) are the activated forms of long‐chain fatty acids and serve as key lipid metabolites. Excess accumulation of intracellular LCACoA, diacylglycerols (DAGs) and ceramides may create insulin resistance with respect to glucose metabolism. We present a new method to measure LCACoA concentrations and isotopic enrichment of palmitoyl‐CoA ([U‐13 C]16‐CoA) and oleoyl‐CoA ([U‐13 C]18:1‐CoA) using ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) to quantitate seven different LCACoA (C14‐CoA, C16‐CoA, C16:1‐CoA, C18‐CoA, C18:1‐CoA, C18:2‐CoA, C20‐CoA). The molecules are separated on a reversed‐phase UPLC column using a binary gradient with ammonium hydroxide (NH4OH) in water and NH4OH in acetonitrile (ACN). The LCACoA are quantified using selected reaction monitoring (SRM) on a triple quadrupole mass spectrometer in positive electrospray ionization (ESI) mode. All LCACoA ions except enriched palmitate enrichment of palmitoyl‐CoA ([U−13C]16‐CoA) and oleoyl‐CoA ([U−13C]18:1‐CoA) using ultra‐performance liquid chromatography/mass spectrometry (UPLC/MS/MS) to quantitate seven different LCACoA (C14‐CoA, C16‐CoA, C16:1‐CoA, C18‐CoA, C18:1‐CoA, C18:2‐CoA, C20‐CoA). The molecules are separated on a reversed‐phase UPLC column using a binary gradient with ammonium hydroxide (NH4OH) in water and NH4OH in acetonitrile. The LCACoA are quantified using selected reaction monitoring (SRM) on a triple quadrupolemass spectrometer in positive electrospray ionization (ESI) mode. All LCACoA ions except enriched palmitate and oleate were monitored as [M + 2 + H]+ and [U13C]16‐CoA and [U13C]18:1‐CoA were monitored as [M + 16 + H]+ and [M + 18 + H]+, respectively. The method is simple, sensitive and efficient (run time as short as 5 min) and allowed us to measure the concentration and detect enrichment in intramyocellular [U13C]16‐CoA and [U13C]18:1‐CoA during a low dose intravenous infusion of [U13C]palmitate and [U13C]oleate in adults undergoing either a saline control experiment or an insulin/glucose infusion experiment. This technique should allow investigators to measure the trafficking of extracellular fatty acids to the intracellular LCACoA pool. Copyright © 2011 John Wiley & Sons, Ltd.
Methods for age‐adjustment of rates
Authors: Inskip Hazel , Beral Valerie , Fraser Patricia , Haskey John
Published: July 2011

Different age structures in two populations complicate any comparison of their levels of mortality. Many methods exist which provide death rates or mortality indices adjusted for age and other factors. Such summary measures inevitably lose information, but they are useful for the initial examination of large quantities of data and for the presentation of results. This paper reviews a number of techniques available for producing age‐adjusted death rates or mortality indices, emphasizing their historical development. Formulae are given for their calculation. The appropriate context for using each method, and its associated disadvantages are described.
An investigation of an excess incidence of heart disease
Authors: Paddle G. M. , Bennett B.
Published: July 2011

In a large complex chemical company, it is difficult to distinguish clusters of disease of occupational origin from those due to non‐occupational factors and those that have arisen by chance. The mechanical application of statistical procedures to health data to detect occupational hazards will produce many false positives. More refined techniques were used to demonstrate that the incidence of coronary disease at a small site was too high to be attributed to chance alone. An intensive search for a causative factor proved abortive.
In‐Situ Observation of Nucleation and Growth of PbSe Magic‐Sized Nanoclusters and Regular Nanocrystals
Authors: Yu Kui , Ouyang Jianying , Leek Donald M.
Published: July 2011

In‐situ observation of the temporal evolution of the absorption of PbSe nanocrystals (NCs) via a low‐temperature noninjection approach is presented. Based on a model reaction of lead oleate (Pb(OA)2) and n‐trioctylphosphine selenide (TOPSe) in 1‐octadecene at 35–80 °C, the use of commercially available TOP (90 or 97%) in affecting the formation of the NCs is explored. TOPSe solutions made from TOP 90% exhibited higher reactivity than those made from TOP 97%. 31P NMR spectroscopy detected no dioctylphosphine selenide (DOPSe) but some DOP in ≈1.0 M TOPSe/TOP solution (made from TOP 90%), as well as no diphenylphosphine selenide (DPPSe) when DPP was added to the ≈1.0 M solution. Hence, it is proposed that, for the formation of PbSe monomers, an indirect pathway dominates with the formation of a Pb–P complex/intermediate, which results from the activation of Pb(OA)2 by a phosphine compound (such as DPP, DOP, or TOP) and in turn reacts with TOPSe. With the use of TOP 90% and the addition of secondary phosphine DPP, the formation of PbSe magic‐sized nanoclusters (MSNCs) and regular NCs (RNCs) is investigated. With proper tuning of the synthesis conditions, the formation of various PbSe MSNCs versus RNCs is monitored in situ with versus without the addition of DPP, or at different reaction temperatures but otherwise identical synthetic formulation and reaction parameters. Accordingly, the degree of supersaturation (DS) of the PbSe monomer affecting the development of these PbSe MSNCs versus RNCs is proposed; the higher the DS, the more the MSNCs are favored. Also, surface‐determined cluster–cluster aggregation is proposed to be the growth mechanism for both the RNCs and MSNCs. For the former, quantized growth is followed by continuous growth. For the latter, the sizes of the magic‐sized families are calculated.
Vaginal micronized progesterone and risk of preterm delivery in high‐risk twin pregnancies: secondary analysis of a placebo‐controlled randomized trial and meta‐analysis
Authors: Klein K. , Rode L. , Nicolaides K. H. , Krampl‐Bettelheim E. , Tabor A. ,   for the PREDICT Group
Published: July 2011

Objectives

Progesterone treatment reduces the risk of preterm delivery in high‐risk singleton pregnancies. Our aim was to evaluate the preventive effect of vaginal progesterone in high‐risk twins.

Methods

This was a subanalysis of a Danish‐Austrian, double‐blind, placebo‐controlled, randomized trial (PREDICT study), in which women with twin pregnancies were randomized to daily treatment with progesterone or placebo pessaries from 20–24 weeks until 34 weeks' gestation. This subpopulation consisted of high‐risk pregnancies, defined by the finding of cervical length ≤ 10th centile at 20–24 weeks' gestation or history of either spontaneous delivery before 34 weeks or miscarriage after 12 weeks. Primary outcome was delivery before 34 weeks. Secondary outcomes were complications for infants including long‐term follow‐up by Ages and Stages Questionnaire (ASQ) at 6 and 18 months of age.

Results

In 72 (10.6%) of the 677 women participating in the PREDICT study, the pregnancy was considered to be high‐risk, including 47 with cervical length ≤ 10th centile, 28 with a history of preterm delivery or late miscarriage and three fulfilling both criteria. Baseline characteristics for progesterone and placebo groups were similar. Mean gestational age at delivery did not differ significantly between the two groups either in patients with a short cervix (34.3 ± 4.1 vs 34.5 ± 3.0 weeks, P = 0.87) or in those with a history of preterm delivery or late miscarriage (34.6 ± 4.2 vs 35.2 ± 2.7 weeks, P = 0.62). Similarly, there were no significant differences between the treatment groups in maternal or neonatal complications and mean ASQ score at 6 and 18 months of age.

Conclusion

In high‐risk twin pregnancies, progesterone treatment does not significantly improve outcome. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Viruses and microRNAs: a toolbox for systematic analysis
Authors: Lieber Diana , Haas Jürgen
Published: July 2011

RNA silencing is emerging as a novel layer of regulation of virus–host interaction. Since individual small RNAs can probably repress dozens if not hundreds of target mRNA molecules, and transcripts, on the other hand, may be recognized by multiple regulatory small RNAs, a dense and complex interaction network of microRNAs (miRNAs) and their targets arises. A comprehensive analysis of miRNA functions thus not only requires systematic approaches employing high‐throughput technologies but also calls for the development of improved experimental technologies and a profound bioinformatic analysis. Integration of complementary approaches will enhance our understanding of the mutual regulation of virus and host. Focusing on herpesviruses, we here describe currently available technologies and summarize present results obtained by high‐throughput approaches. These techniques can be broadly applied to other virus families and pathways employing other classes of small regulatory RNAs and therefore are powerful universal tools for research on virus–host interaction. WIREs RNA 2011 2 787–801 DOI: 10.1002/wrna.92

This article is categorized under:

Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action

RNA Methods > RNA Analyses In Vitro and In Silico

RNA Methods > RNA Analyses in Cells
Metastatic Castrate-Resistant Prostate Cancer: New Landscape, New Challenges
Authors: Bahl Amit , Persad Raj
Published: July 2011

Just 5 years after docetaxel was recommended by the National Institute for Health and Clinical Excellence as the standard of care for metastatic castrate-resistant prostate cancer, a novel taxane—cabazitaxel—has been licensed in Europe and the USA for a similar indication. It is authorised for use in patients whose disease progresses after docetaxel, for whom it has been shown to provide a survival benefit over current palliative strategies. However, it is not the only new treatment for this population of patients. The hormonal agent abiraterone has also been licensed in the USA, and is expected to receive a European licence later this year, the sipuleucel-T vaccine has been approved in the USA, and other agents are on the near horizon. While these advances are undoubtedly welcome, much thought will need to be given to their optimal use in terms of patient selection, the timing/sequencing of treatment, and to the design of the prostate cancer treatment paradigm. It will also be important to consider the impact that new agents will have on healthcare spending and capacity.
Seroprevalence of toxocariasis in hypereosinophilic individuals in Ahwaz, south-western Iran
Authors: Maraghi S. , Rafiei A. , Hajihossein R. , Sadjjadi S. M.
Published: July 2011

Eosinophilia in human peripheral blood is caused by different agents, including toxocariasis. The present study aimed to evaluate the prevalence of toxocariasis in hypereosinophilic individuals in the city of Ahwaz, located in south-western Iran, using enzyme-linked immunosorbent assay and Western blot techniques. Serum samples were examined from 100 individuals with peripheral blood eosinophilia and also from another 100 individuals without eosinophilia as the control group. In hypereosinophilic individuals seroprevalence antibodies againstToxocarawere found in 19 (19%), of whom 12 (63.15%) were female and 7 (36.85%) were male. Positive sera were subsequently confirmed by Western blot. All of the observed bands ranged from 24 to 100 kDa. Antibodies againstToxocarawere found in 1% of the control group, but were not confirmed by Western blot. The results showed significant differences between the frequency of infection within age and gender (P < 0.05); the highest prevalence of infection was observed in adults. Differences between the hypereosinophilic and healthy individuals, in terms ofToxocarainfection frequency, also proved significant (P < 0.05).The present study thus confirmed the significant prevalence of toxocariasis as a hygienic problem among hypereosinophilic individuals in this area. It is, therefore, necessary to examine these individuals for toxocariasis.
First-episode psychosis is characterized by failure of deactivation but not by hypo- or hyperfrontality
Authors: Guerrero-Pedraza A. , McKenna P. J. , Gomar J. J. , Sarró S. , Salvador R. , Amann B. , Carrión M. I. , Landin-Romero R. , Blanch J. , Pomarol-Clotet E.
Published: July 2011

Background

It is not known whether first-episode psychosis is characterized by the same prefrontal cortex functional imaging abnormalities as chronic schizophrenia.

Method

Thirty patients with a first episode of non-affective functional psychosis and 28 healthy controls underwent functional magnetic resonance imaging (fMRI) during performance of the n-back working memory task. Voxel-based analyses of brain activations and deactivations were carried out and compared between groups. The connectivity of regions of significant difference between the patients and controls was also examined.

Results

The first-episode patients did not show significant prefrontal hypo- or hyperactivation compared to controls. However, they showed failure of deactivation in the medial frontal cortex. This area showed high levels of connectivity with the posterior cingulate gyrus/precuneus and parts of the parietal cortex bilaterally. Failure of deactivation was significantly greater in first-episode patients who had or went on to acquire a DSM-IV diagnosis of schizophrenia than in those who did not, and in those who met RDC criteria for schizophrenia compared to those who did not.

Conclusions

First-episode psychosis is not characterized by hypo- or hyperfrontality but instead by a failure of deactivation in the medial frontal cortex. The location and connectivity of this area suggest that it is part of the default mode network. The failure of deactivation seems to be particularly marked in first-episode patients who have, or progress to, schizophrenia.
‘God told me to do it’: sceptical theism and perceiving God
Authors: SEIGAL JOSHUA
Published: July 2011

In this article I highlight a tension between Alston's core thesis in his seminal book Perceiving God – that beliefs about God formed on the basis of mystical perception are prima facie justified – and a currently popular method for disarming a certain form of the argument from evil, a method which involves adopting a view known as sceptical theism.
Eliciting expert opinion on the effectiveness and practicality of interventions in the farm and rural environment to reduce human exposure to Escherichia coli O157
Authors: CROSS P. , RIGBY D. , EDWARDS-JONES G.
Published: July 2011

Few hard data are available on emergent diseases. However, the need to mitigate and manage emergent diseases has prompted the use of various expert consultation and opinion elicitation methods. We adapted best-worst scaling (BWS) to elicit experts' assessment of the relative practicality and effectiveness of measures to reduce human exposure to E. coli O157. Cattle vaccination was considered the most effective and hand-washing was considered the most practical measure. BWS proved a powerful tool for expert elicitation as it breaks down a cognitively burdensome process into simple, repeated, tasks. In addition, statistical analysis of the resulting data provides a scaled set of scores for the measures, rather than just a ranking. The use of two criteria (practicality and effectiveness) within the BWS process allows the identification of subsets of measures judged as potentially performing well on both criteria, and conversely those judged to be neither effective nor practical.
Emergence of metallo-β-lactamase IMP-14 and VIM-2 inPseudomonas aeruginosaclinical isolates from a tertiary-level hospital in Thailand
Authors: PIYAKUL C. , TIYAWISUTSRI R. , BOONBUMRUNG K.
Published: July 2011

Seventy-five clinical isolates ofPseudomonas aeruginosacollected in a tertiary teaching hospital in Thailand were investigated for susceptibility to antimicrobials including imipenem. Metallo-β-lactamase (MBL) enzymes were detected by E-test MBL assay and PCR; class 1 integron genes were also detected by PCR. Strains positive forblaIMPandblaVIMgenes were further characterized by DNA sequencing and examined for clonality by pulsed-field gel electrophoresis. High rates of resistance to anti-pseudomonal agents were found. MBL enzymes were found in 13 (17·3%) strains and 24 (32%) carried class 1 integron genes. Twelve of the latter strains harboured theblaIMP-14gene and one strain theblaVIM-2gene. All of the IMP-14 strains were identical or closely related suggesting clonal dissemination of these genes.
Do Latino and non-Latino grocery stores differ in the availability and affordability of healthy food items in a low-income, metropolitan region?
Authors: Emond Jennifer A , Madanat Hala N , Ayala Guadalupe X
Published: July 2011

Objective

To compare non-ethnically based supermarkets and Latino grocery stores (tiendas) in a lower-income region with regard to the availability, quality and cost of several healthy v. unhealthy food items.

Design

A cross-sectional study conducted by three independent observers to audit twenty-five grocery stores identified as the main source of groceries for 80 % of Latino families enrolled in a childhood obesity study. Stores were classified as supermarkets and tiendas on the basis of key characteristics.

Setting

South San Diego County.

Subjects

Ten tiendas and fifteen supermarkets.

Results

Tiendas were smaller than supermarkets (five v. twelve aisles, P = 0·003). Availability of fresh produce did not differ by store type; quality differed for one fruit item. Price per unit (pound or piece) was lower in tiendas for most fresh produce. The cost of meeting the US Department of Agriculture's recommended weekly servings of produce based on an 8368 kJ (2000 kcal)/d diet was $US 3·00 lower in tiendas compared with supermarkets (P < 0·001). The cost of 1 gallon of skimmed milk was significantly higher in tiendas ($US 3·29 v. $US 2·69; P = 0·005) and lean (7 % fat) ground beef was available in only one tienda (10 %) compared with ten (67 %) supermarkets (P = 0·01).

Conclusions

Barriers remain in the ability to purchase healthier dairy and meat options in tiendas; the same is not true for produce. These results highlight the potential that tiendas have in improving access to quality, fresh produce within lower-income communities. However, efforts are needed to increase the access and affordability of healthy dairy and meat products.
Dietary habits and inadequate control of blood pressure in hypertensive adults assisted by a Brazilian Family Doctor Program
Authors: da Silva Nalin de Souza Bárbara , Garcia Rosa Maria Luiza , Lugon Jocemir R , Yokoo Edna Massae , Mesquita Evandro Tinoco , Rodrigues Michele , da Silva Ramos Carolina , Cagy Maurício
Published: July 2011

Objective

To estimate dietary habits and other factors associated with inadequate blood pressure (BP) control in hypertensive patients adherent to antihypertensive drug treatment assisted by a Brazilian Family Doctor Program (FDP).

Design

A cross-sectional study.

Setting

FDP units, Niterói, Rio de Janeiro, Brazil.

Subjects

We included data from both male and female participants aged ≥20 years. Participants completed a standardized questionnaire containing questions related to demographics, socio-economic factors, comorbidities and lifestyle, as well as a validated FFQ and eleven additional qualitative questions to investigate dietary habits. Food items were divided into sixteen groups. Medical consultations were performed, BP measurements were taken, blood and urine samples were assessed and anthropometric and nutritional status was evaluated.

Results

Individuals with inadequate BP control presented higher BMI values (prevalence ratio (PR) = 1·027, 95 % CI 1·009, 1·045) and also consumed more meat (PR = 1·091, 95 % CI 1·022, 1·165), which are potentially modifiable variables. Higher levels of serum creatinine (PR = 1·894, 95 % CI 1·241, 2·892) were also associated with inadequate BP control, as were skin colour (white). After inclusion of the Na excretion index, which is an indirect measure of salt intake, a slight decrease was observed in the PR for meat, which resulted in loss of statistical significance.

Conclusions

The results indicate that salt consumption, skin colour, BMI and serum creatinine are associated with inadequate BP control.
Mental health economics: current methodological issues
Authors: McCrone P.
Published: July 2011

Background:

Investment in innovative mental health care services requires the use of scarce resources that could be used in alternative ways. Economic evaluation is essential to ensure that such an investment is appropriately compared with investment elsewhere.

Method:

A non-systematic review of mental health evaluations identifies key methodological issues pertaining to economic studies.

Results:

Economic evaluations require the measurement and combination of costs and outcomes, and clarity about how this measurement is undertaken is required. Regarding costs, important considerations relate to the perspective to be taken (e.g., health service or societal), method of measurement (patient self-report or use of databases) and valuation (actual costs, fees or expenditure). Decision makers frequently need to compare evidence both within and between clinical areas and therefore there is a tension between the use of condition specific and generic outcome measures. Quality-adjusted life years are frequently used in economic evaluations, but their appropriateness in mental health care studies is still debated.

Conclusions:

Economic evaluations in the area of mental health care are increasing in number and it is essential that researchers continue to develop and improve methods used to conduct such studies.
Coping Style as a Mediator of the Relationship Between Depressive Symptoms and Deliberate Self-Harm
Authors: Christian Allison S. , McCabe Kristen M.
Published: July 2011

Background: Deliberate self-harm (DSH) occurs with high frequency among clinical and nonclinical youth populations. Although depression has been consistently linked with the behavior, not all depressed individuals engage in DSH. Aims: The current study examined maladaptive coping strategies (i.e., self-blame, distancing, and self-isolation) as mediators between depression and DSH among undergraduate students. Methods: 202 students from undergraduate psychology courses at a private university in Southern California (77.7% women) completed anonymous self-report measures. Results: A hierarchical regression model found no differences in DSH history across demographic variables. Among coping variables, self-isolation alone was significantly related to DSH. A full meditational model was supported: Depressive symptoms were significantly related to DSH, but adding self-isolation to the model rendered the relationship nonsignificant. Limitations: The cross-sectional study design prevents determination of whether a casual relation exists between self-isolation and DSH, and obscures the direction of that relationship. Conclusions: Results suggest targeting self-isolation as a means of DSH prevention and intervention among nonclinical, youth populations.
How Henry Hellyer’s Use of Language Foretold His Suicide
Authors: Baddeley Jenna L. , Daniel Gwyneth R. , Pennebaker James W.
Published: July 2011

Background: Henry Hellyer was an accomplished surveyor and explorer in Australia in the early 1800s whose apparent suicide at the age of 42 has puzzled historians for generations. He left behind several written works, including letters, journals, and reports. Aims: The current study assessed changes in the ways Hellyer used words in his various written documents during the last 7 years of his life. Methods: Hellyer’s writings were analyzed using the Linguistic Inquiry and Word Count program. Results: Hellyer showed increases in first-person singular pronoun use, decreases in first-person plural pronoun use, and increases in negative emotion word use. As this is a single, uncontrolled case study, caution is recommended in generalizing from the current results. Conclusions: Results suggest Hellyer’s increasing self-focused attention, social isolation, and negative emotion. Findings are consistent with increasing depression and suicidal ideation. Implications for using computerized text analysis to decode people’s psychological states from their written records are discussed.
Understanding the Risks of Recent Discharge
Authors: Cutcliffe John R. , Links Paul S. , Harder Henry G. , Balderson Ken , Bergmans Yvonne , Eynan Rahel , Ambreen Munazah , Nisenbaum Rosanne
Published: July 2011

Background: Evidence indicates that people whose mental health problems lead them to require psychiatric hospitalization are at a significantly increased risk of suicide, and that the time immediately following discharge after such hospitalizations is a particularly high-risk time. Aims: This paper reports on phenomenological findings from a federally funded, mixed-methods study that sought to better understand the observed increased risk for suicide following discharge from an inpatient psychiatric service. Methods: A purposive sample of 20 recently discharged former suicidal inpatients was obtained. Data were collected in hermeneutic interviews lasting between 1 h and 2 h and analyzed according to van Manen’s (1997 ) interpretation of hermeneutic phenomenology. Results: Two key themes, “existential angst at the prospect of discharge” and “trying to survive while living under the proverbial ‘sword of Damocles’” were induced. Each of these was comprised of five themes with the first key theme (which is the focus of this paper) encompassing the following: “Feeling scared, anxious, fearful and/or stressed,” “Preparedness,” “Leaving the place of safety,” “Duality and ambivalence,” and “Feel like a burden.” Conclusions: Early exploration of and reconciling of patients’ expectations regarding inpatient care for their suicidality would be empirically based interventions that could diminish the postdischarge risk for further suicide attempts.
Large‐scale modeling of primary production and ice algal biomass within arctic sea ice in 1992
Authors: Deal Clara , Jin Meibing , Elliott Scott , Hunke Elizabeth , Maltrud Mathew , Jeffery Nicole
Published: July 2011

An ice ecosystem model was coupled to a global dynamic sea ice model to assess large‐scale variability of primary production and ice algal biomass within arctic sea ice. The component models are the Physical Ecosystem Model (PhEcoM) ice ecosystem model and the Los Alamos Sea Ice Model (CICE). Simulated annual arctic sea ice primary production was 15.1 Tg C; within the range of 9 to 73 Tg C estimated using in situ data. The amount of C fixed was >3 Tg C month−1 for March, April, and May. The Bering Sea, Arctic Ocean basins, and the Canadian Archipelago/Baffin Bay were the most productive regions on an annual basis, contributing approximately 24, 18, and another 18%, respectively. High production in the Bering Sea was due to high daily production rates, while the large sea ice coverage in the Canadian Archipelago/Baffin Bay and, in particular, the Arctic Ocean basins resulted in their considerable contribution to sea ice primary production. The simulated trends, patterns, and seasonality of ice algae agree reasonably well with very limited observations. In the model, ice growth rate controls the availability of nutrients to sea ice algae, such that ocean nutrient supply is of secondary importance to ice algal growth. The numerical model results suggest that ice melt rate, which determines the proportional rate of ice algal release, controls the termination of the bloom on large scales. The model described advances the role of sea ice algae in biogeochemical cycling within global climate models.
Sustainable tourism pedagogy and academic-community collaboration: A progressive service-learning approach
Authors: Jamal Tazim , Taillon Justin , Dredge Dianne
Published: July 2011

This article proposes a progressive, experiential and collaborative approach to sustainable tourism pedagogy (STP). Six core STP literacies (technical, analytical, ecological, multi-cultural, ethical, policy and political) are identified, which guide skill and knowledge development for the sustainability practitioner. These are facilitated through experiential education in the field that facilitates critical thinking, practical knowledge and participatory action. It is argued that a critical reflexive stance combined with a collaborative community service-learning approach in STP enables phronesis (practical wisdom) and praxis (social change). A case example is provided of an academic-community collaboration involving undergraduate students, local public and private sector stakeholders, plus diverse rural residents that came together temporarily to explore a cultural heritage issue and challenge. This collaboration facilitated collaborative learning, diverse community involvement and community service. The case overview illustrates a teaching opportunity that conveys how some of these STP priorities were undertaken, including the need for critical social action (to address not only environmental issues but also social-cultural sustainability issues related to the well-being of minority, marginalized and diverse populations).
Numerical-simulation and experimental-validation of the largest Egyptian solar process-heat system
Authors: Abdel-Dayem Adel M.
Published: July 2011

El-Nasr pharmaceutical solar process heat project is considered as the largest industrial system installed and working in east Cairo, Egypt 30°N. It was simply constructed from a one-axis tracking parabolic-trough collector that can produce about 1.3 ton/h saturated steam to feed the industrial processes in the company. Twenty-three bar compressed water is heated inside 1958.4 m2 collectors, and later on it is flashed in a steam flash-drum to produce saturated steam at 8 bars and 175 °C that is fed to the process heat. A mathematical model was developed for the system components to simulate annual performance of the system. The simulation results were verified successfully by the measured data that are monitoring the system performance. First, each component of the mathematical model was experimentally validated separately. Accordingly, the whole mathematical model was validated under different weather conditions along the year. The validated numerical model was optimized. The optimal number of collectors connected in series was obtained as three collectors not 36 as installed. An economical study of the installed system was provided. The optimal design of the system was economically estimated. The optimal collector area is less than that installed, it equals about 538 m2. Annual performance of the system is presented indicating the seasonal variation. It was found that the optimized system can produce about 2 ton/h in average. Moreover, that value is more than that was proposed by the system design.
Bifurcations of dividing surfaces in chemical reactions
Authors: Iñarrea Manuel , Palacián Jesús F. , Pascual Ana Isabel , Salas J. Pablo
Published: July 2011

We study the dynamical behavior of the unstable periodic orbit (NHIM) associated to the non-return transition state (TS) of the H2 + H collinear exchange reaction and their effects on the reaction probability. By means of the normal form of the Hamiltonian in the vicinity of the phase space saddle point, we obtain explicit expressions of the dynamical structures that rule the reaction. Taking advantage of the straightforward identification of the TS in normal form coordinates, we calculate the reaction probability as a function of the system energy in a more efficient way than the standard Monte Carlo method. The reaction probability values computed by both methods are not in agreement for high energies. We study by numerical continuation the bifurcations experienced by the NHIM as the energy increases. We find that the occurrence of new periodic orbits emanated from these bifurcations prevents the existence of a unique non-return TS, so that for high energies, the transition state theory cannot be longer applied to calculate the reaction probability.
Equilibrium structure of the multi-component screened charged hard-sphere fluid
Authors: Sánchez-Díaz Luis E. , Mendez-Maldonado Gloria A. , González-Melchor Minerva , Ruiz-Estrada Honorina , Medina-Noyola Magdaleno
Published: July 2011

The generalized mean spherical approximation of the structural properties of the binary charge-symmetric fluid of screened charged hard-spheres of the same diameter, i.e., the screened restricted primitive model, is extended to include binary charge-asymmetric and multi-component fluids. Molecular dynamics simulation data are generated to assess the accuracy of the corresponding theoretical predictions.
Thermally induced multi-loop hysteresis in the photoluminescence of semiconductor polaritons
Authors: Parreira Júlia E. , Saldanha Pablo L. , Nemes M. C.
Published: July 2011

We show that multi-loop hysteresis, recently observed by Cotta and Matinaga in semiconductor optical cavities in the strong coupling regime [Phys. Rev. B. 76, 073308 (2007)], can be explained as a competition between the externally controlled pumping intensity and the delayed response of the well in delivering heat to the bottom of the base. As the external pump intensity grows, the material heats proportionally. However, when the pump intensity decreases, the system cannot deliver heat to the cooled base at the same rate, and the temperature decreases with a delay in relation to the pump intensity. This time mismatch is responsible for the hysteresis and the crossing of the curves. We also show how this type of experiment can be used to clarify the complicated process of thermal dynamics in semiconductors.
Effect of Iron compounds on hyperfine interactions and methane formation in the coal
Authors: Skoblik A. P. , Shanina B. D. , Okulov S. M. , Ulyanova E. V. , Shpak A. P. , Gavriljuk V. G.
Published: July 2011

Using Mössbauer spectroscopy and electron paramagnetic resonance, it is shown that Fe2+ and Fe3+ compounds in the coal increase the spin concentration in the carbon nanoclusters (aromatic area) and in the intercluster space (aliphatic medium). The Fe2+ compounds preferentially support the increase of dangled bonds in carbon nanoclusters, whereas the Fe3+ ones assist the formation of free radicals in the intercluster space. By means of the electron-nuclear double resonance, it is shown that hydrogen atoms are located in the both nanoclusters and intercluster space with the higher hydrogen content in the intercluster space. The saturation of dangled bonds by hydrogen and the increase in the fraction of free radicals serve as prerequisites for methane formation. In comparison with Fe3+, the Fe2+ compounds are more effective as catalysts for methane formation.
Signature of quantum interference and the Fano resonances in the transmission spectrum of bilayer graphene nanostructure
Authors: Mukhopadhyay S. , Biswas R. , Sinha C.
Published: July 2011

The well-known asymmetric Fano resonances that results from the quantum interference between the discrete and the continuum states are noted for the first time in the ballistic transmission spectrum of the bilayer graphene tunneling structures. This unconventional tunneling transmission, in stark contrast to the monolayer graphene and to the conventional heterostructures, arises due to the quadratic dispersion of the chiral charge carriers. If the Klein tunneling (the phenomenon for normal incidence) is an unusual characteristic of the massless chiral particles, then the Fano tunneling (the phenomenon for low glancing incidence) would be the specialty for the massive chiral particles. The characteristic features of the Fano line shape are found to be highly sensitive to the direction of incidence of the charge carriers, the applied homogeneous electric field, and to the barrier height. The sharp anti-resonance at the center of the tunneling band arising due to the destructive interference between the electron and the holelike states could probably be responsible for the high negative differential conductance (NDC) in the bilayer graphene. The tunneling conductance in the double barrier structure exhibits a resonant peak with a sharp NDC region for the Fermi energy less than or equal to half of the barrier height. The present findings might have great implications in the preparation of NDC-based devices using bilayer graphene nanostructures.
Glass forming ability of the Mo-Pd system studied by thermodynamic modeling and ion beam mixing
Authors: Ding N. , Li J. H. , Liu B. X.
Published: July 2011

Glass forming ability/range of the Mo-Pd binary metal system was studied by thermodynamic calculations employing Miedema’s model and ion beam mixing of multiple metal layers. The thermodynamic calculations predict a narrow composition range of 8–26 at% Pd, within which metallic glass formation is energetically favored, whereas the experimental results showed that ion beam mixing was able to synthesize metallic glasses within a composition range 13–30 at% Pd, which was well in accordance with the prediction. Besides, in the Mo70Pd30 multilayered films, with varying the irradiation dose, a dual-phase metallic glass was formed, and it could be considered as an intermediate state. The possible mechanism for the formation of the metallic glasses was also discussed in terms of the atomic collision theory.
Dirac method and symplectic submanifolds in the cotangent bundle of a factorizable Lie group
Authors: Capriotti S. , Montani H.
Published: July 2011

We study some symplectic submanifolds in the cotangent bundle of a factorizable Lie group defined by second class constraints. By applying the Dirac method, we study many issues of these spaces as fundamental Dirac brackets, symmetries, and collective dynamics. As the main application, we study integrable systems on these submanifolds as inherited from a system on the whole cotangent bundle, meeting in a natural way with the Adler-Kostant-Symes theory of integrability.
Generalized self-duality equations of polynomial type in Yang-Mills theories
Authors: Kihara Hironobu
Published: July 2011

The purpose of this paper is to generalize the self-duality equation by Tchrakian and Corrigan et al.Novel generalized self-duality equations on higher-dimensional spaces are discussed. This class of equations includes the usual self-duality equation for four-dimensional spaces. Some of the generalized self-duality equations over-determine configurations and the existence of solutions is not trivial. Several examples of solutions of the equations are demonstrated. As an application of the equations, it is proved that some of those solutions solve the equations of motion derived from rotationally invariant actions, which consist of single-trace terms and are second order in the time derivative.
Dimension reduction by balanced truncation: Application to light-induced control of open quantum systems
Authors: Schäfer-Bung Boris , Hartmann Carsten , Schmidt Burkhard , Schütte Christof
Published: July 2011

In linear control, balanced truncation is known as a powerful technique to reduce the state-space dimension of a system. Its basic principle is to identify a subspace of jointly easily controllable and observable states and then to restrict the dynamics to this subspace without changing the overall response of the system. This work deals with a first application of balanced truncation to the control of open quantum systems which are modeled by the Liouville-von Neumann equation within the Lindblad formalism. Generalization of the linear theory has been proposed to cope with the bilinear terms arising from the coupling between the control field and the quantum system. As an example we choose the dissipative quantum dynamics of a particle in an asymmetric double well potential driven by an external control field, monitoring population transfer between the potential wells as a control target. The accuracy of dimension reduction is investigated by comparing the populations obtained for the truncated system versus those for the original system. The dimension of the model system can be reduced very efficiently where the degree of reduction depends on temperature and relaxation rate.
Analytical Hessian of electronic excited states in time-dependent density functional theory with Tamm-Dancoff approximation
Authors: Liu Jie , Liang WanZhen
Published: July 2011

We present the analytical expression and computer implementation for the second-order energy derivatives of the electronic excited state with respect to the nuclear coordinates in the time-dependent density functional theory (TDDFT) with Gaussian atomic orbital basis sets. Here, the Tamm-Dancoff approximation to the full TDDFT is adopted, and therefore the formulation process of TDDFT excited-state Hessian is similar to that of configuration interaction singles (CIS) Hessian. However, due to the replacement of the Hartree-Fock exchange integrals in CIS with the exchange-correlation kernels in TDDFT, many quantitative changes in the derived equations are arisen. The replacement also causes additional technical difficulties associated with the calculation of a large number of multiple-order functional derivatives with respect to the density variables and the nuclear coordinates. Numerical tests on a set of test molecules are performed. The simulated excited-state vibrational frequencies by the analytical Hessian approach are compared with those computed by CIS and the finite-difference method. It is found that the analytical Hessian method is superior to the finite-difference method in terms of the computational accuracy and efficiency. The numerical differentiation can be difficult due to root flipping for excited states that are close in energy. TDDFT yields more exact excited-state vibrational frequencies than CIS, which usually overestimates the values.
Dual stage resistive transition of MgB2 evidenced by noise analysis
Authors: Andreoli V. , Carbone A. , Mazzetti P. , Gandini C. , Masoero A. , Monticone E.
Published: July 2011

The resistive transition of polycrystalline superconducting MgB2 films is studied by means of an extensive set of stationary noise measurements, going from the very beginning of the transition to its final point, where the normal state is reached, either with and without magnetic field. The experimental results, taken at low current density and close to the critical temperature Tc, show very clearly the existence of two different dissipative processes at the different stages of the transition. An extended analysis proves that, at the beginning of the transition, when the resistance is below ten percent of normal value, the specimen is in a mixed state and dissipation is produced by fluxoid creation and motion. At higher temperature the specimen is in an intermediate state, constituted by a structure of interleaved superconducting and resistive domains. Such a situation occurs in type II superconductor when the transition temperature is very near to Tc and the critical field Hc for fluxoid penetration tends to zero. It is found that in the intermediate state, the power spectrum of the relative resistance fluctuations, is independent of the average resistance value and is unaffected by the magnetic field. As shown in the paper, this means that the noise is generated by density fluctuation of the normal electron gas in the resistive domains, while the contribution of the superconducting ones is negligible. The reduced noise amplitude does not depend on the steepness of the transition curve, thus adding further evidence to the above interpretation. The noise is thus related to the film impurities and can be investigated when the specimen is in the normal state, even at room temperature. The occurrence of a different dissipative process at low resistance is clearly evidenced by the experimental results, which show that the amplitude of the reduced power spectrum of the noise depends on magnetic field and resistance. These results are consistent with the assumption of fluxoid noise as shown by the model for the calculation of the noise developed in the manuscript.
Nanosecond square high voltage pulse generator for electro-optic switch
Authors: Feng Xian-wang , Long Xing-wu , Tan Zhong-qi
Published: July 2011

A scalable square high voltage pulse generator, which has the properties of fast rise time, fast fall time, powerful driving capability, and long lifetime, is presented in this paper by utilizing solid state circuitry. A totem-pole topology is designed to supply a powerful driving capability for the electro-optic (EO) crystal which is of capacitive load. Power MOSFETs are configured in series to sustain high voltage, and proper driving circuits are introduced for the specific MOSFETs configurations. A 3000 V pulse generator with ∼49.04 ns rise time and ∼10.40 ns fall time of the output waveform is presented. This kind of generator is desirable for electro-optic switch. However, it is not specific to EO switch and may have broad applications where high voltage fast switching is required.