bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial parasite ecology and epidemiology: a review of methods and applications
Authors: PULLAN RACHEL L. , STURROCK HUGH J. W. , SOARES MAGALHÃES RICARDO J. , CLEMENTS ARCHIE C. A. , BROOKER SIMON J.
Published: November 2012

The distributions of parasitic diseases are determined by complex factors, including many that are distributed in space. A variety of statistical methods are now readily accessible to researchers providing opportunities for describing and ultimately understanding and predicting spatial distributions. This review provides an overview of the spatial statistical methods available to parasitologists, ecologists and epidemiologists and discusses how such methods have yielded new insights into the ecology and epidemiology of infection and disease. The review is structured according to the three major branches of spatial statistics: continuous spatial variation; discrete spatial variation; and spatial point processes.
Environmental determinants ofIxodes ricinusticks and the incidence ofBorrelia burgdorferisensu lato, the agent of Lyme borreliosis, in Scotland
Authors: JAMES M. C. , BOWMAN A. S. , FORBES K. J. , LEWIS F. , MCLEOD J. E. , GILBERT L.
Published: November 2012

Lyme borreliosis (LB) is the most common arthropod-borne disease of humans in the Northern hemisphere. In Europe, the causative agent,Borrelia burgdorferisensu lato complex, is principally vectored byIxodes ricinusticks. The aim of this study was to identify environmental factors influencing questingI. ricinusnymph abundance andB. burgdorferis.l. infection in questing nymphs using a large-scale survey across Scotland. Ticks, host dung and vegetation were surveyed at 25 woodland sites, and climatic variables from a Geographical Information System (GIS) were extracted for each site. A total of 2397 10 m2transect surveys were conducted and 13 250I. ricinusnymphs counted. Questing nymphs were assayed forB. burgdorferis.l. and the average infection prevalence was 5·6% (range 0·8–13·9%). More questing nymphs and higher incidence ofB. burgdorferis.l. infection were found in areas with higher deer abundance and in mixed/deciduous compared to coniferous forests, as well as weaker correlations with season, altitude, rainfall and ground vegetation. No correlation was found between nymph abundance and infection prevalence within the ranges encountered. An understanding of the environmental conditions associated with tick abundance and pathogen prevalence may be used to reduce risk of exposure and to predict future pathogen prevalence and distributions under environmental changes.
Psychological treatment of anxiety in primary care: a meta-analysis
Authors: Seekles W. , Cuijpers P. , Kok R. , Beekman A. , van Marwijk H. , van Straten A.
Published: November 2012

Background

Guidelines and mental healthcare models suggest the use of psychological treatment for anxiety disorders in primary care but systematic estimates of the effect sizes in primary care settings are lacking. The aim of this study was to examine the effectiveness of psychological therapies in primary care for anxiety disorders.

Method

The Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Medline, PsycINFO and Pubmed databases were searched in July 2010. Manuscripts describing psychological treatment for anxiety disorders/increased level of anxiety symptoms in primary care were included if the research design was a randomized controlled trial (RCT) and if the psychological treatment was compared with a control group.

Results

In total, 1343 abstracts were identified. Of these, 12 manuscripts described an RCT comparing psychological treatment for anxiety with a control group in primary care. The pooled standardized effect size (12 comparisons) for reduced symptoms of anxiety at post-intervention wasd = 0.57 [95% confidence interval (CI) 0.29–0.84,p = 0.00, the number needed to treat (NNT) = 3.18]. Heterogeneity was significant among the studies (I2 = 58.55,Q = 26.54,p < 0.01). The quality of studies was not optimal and missing aspects are summarized.

Conclusions

We found a moderate effect size for the psychological treatment of anxiety disorders in primary care. Several aspects of the treatment are related to effect size. More studies are needed to evaluate the long-term effects given the chronicity and recurrent nature of anxiety.
Does exercise improve self-reported sleep quality in non-remitted major depressive disorder?
Authors: Rethorst C. D. , Sunderajan P. , Greer T. L. , Grannemann B. D. , Nakonezny P. A. , Carmody T. J. , Trivedi M. H.
Published: November 2012

Background

Sleep disturbances are persistent residual symptoms following remission of major depressive disorder (MDD) and are associated with an increased risk of MDD recurrence. The purpose of the current study was to examine the effect of exercise augmentation on self-reported sleep quality in participants with non-remitted MDD.

Method

Participants were randomized to receive selective serotonin reuptake inhibitor (SSRI) augmentation with one of two doses of exercise: 16 kilocalories per kilogram of body weight per week (KKW) or 4 KKW for 12 weeks. Depressive symptoms were assessed using the clinician-rated Inventory of Depressive Symptomatology (IDS-C). The four sleep-related items on the IDS-C (Sleep Onset Insomnia, Mid-Nocturnal Insomnia, Early Morning Insomnia, and Hypersomnia) were used to assess self-reported sleep quality.

Results

Significant decreases in total insomnia (p < 0.0001) were observed, along with decreases in sleep onset, mid-nocturnal and early-morning insomnia (p's <0.002). Hypersomnia did not change significantly (p = 0.38). Changes in total, mid-nocturnal and early-morning insomnia were independent of changes in depressive symptoms. Higher baseline hypersomnia predicted a greater decrease in depression severity following exercise treatment (p = 0.0057). No significant moderating effect of any baseline sleep on change in depression severity was observed. There were no significant differences between exercise treatment groups on total insomnia or any individual sleep item.

Conclusions

Exercise augmentation resulted in improvements in self-reported sleep quality in patients with non-remitted MDD. Given the prevalence of insomnia as a residual symptom following MDD treatment and the associated risk of MDD recurrence, exercise augmentation may have an important role in the treatment of MDD.
Effects of cortisol on memory in women with borderline personality disorder: role of co-morbid post-traumatic stress disorder and major depression
Authors: Wingenfeld K. , Driessen M. , Terfehr K. , Schlosser N. , Fernando S. Carvalho , Otte C. , Beblo T. , Spitzer C. , Löwe B. , Wolf O. T.
Published: November 2012

Background

Stress and cortisol administration are known to have impairing effects on memory retrieval in healthy humans. These effects are reported to be altered in patients with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) but they have not yet been investigated in borderline personality disorder (BPD).

Method

In a placebo-controlled cross-over study, 71 women with BPD and 40 healthy controls received either placebo or 10 mg of hydrocortisone orally before undertaking a declarative memory retrieval task (word list learning) and an autobiographical memory test (AMT). A working memory test was also applied.

Results

Overall, opposing effects of cortisol on memory were observed when comparing patients with controls. In controls, cortisol had impairing effects on memory retrieval whereas in BPD patients cortisol had enhancing effects on memory retrieval of words, autobiographical memory and working memory. These effects were most pronounced for specificity of autobiographical memory retrieval. Patients with BPD alone and those with co-morbid PTSD showed this effect. We also found that co-morbid MDD influenced the cortisol effects: in this subgroup (BPD + MDD) the effects of cortisol on memory were absent.

Conclusions

The present results demonstrate beneficial effects of acute cortisol elevations on hippocampal-mediated memory processes in BPD. The absence of these effects in patients with co-morbid MDD suggests that these patients differ from other BPD patients in terms of their sensitivity to glucocorticoids (GCs).
Adolescent bullying, cannabis use and emerging psychotic experiences: a longitudinal general population study
Authors: Mackie C. J. , O'Leary-Barrett M. , Al-Khudhairy N. , Castellanos-Ryan N. , Struve M. , Topper L. , Conrod P.
Published: November 2012

Background

Using longitudinal and prospective measures of psychotic experiences during adolescence, we assessed the risk of developing psychosis in three groups showing low, increasing and elevated psychotic experiences associated with bullying by peers and cannabis use in a UK sample of adolescents.

Method

Data were collected by self-report from 1098 adolescents (mean age 13.6 years; 60.9% boys) at five separate time points, equally separated by 6 months, across a 24-month period. General growth mixture modelling identified three distinct trajectories of adolescents reporting psychotic experiences: elevated, increasing and low.

Results

Controlling for cannabis use, bullying by peers significantly predicted change in psychotic experiences between Time 2 and Time 5 in adolescents belonging to the increasing group. No effect was found for the elevated or low groups. Controlling for bullying, an earlier age of cannabis use and cannabis use more than twice significantly predicted change in psychotic experiences in adolescents belonging to the increasing group. Cannabis use at any age was significantly associated with subsequent change in psychotic experiences in the low group. Reverse causal associations were examined and there was no evidence for psychotic experiences at Time 1 predicting a subsequent change in cannabis use between Times 2 and 5 in any trajectory group.

Conclusions

Bullying by peers and cannabis use are associated with adolescents' reports of increasing psychotic experiences over time. Further research into the longitudinal development of psychosis in adolescence and the associated risk factors would allow for early intervention programmes to be targeted more precisely.
War, Tropical Disease, and the Emergence of National Public Health Capacity in the United States
Authors: Sledge Daniel
Published: November 2012

This article analyzes the emergence of national public health capacity in the United States. Tracing the transformation of the federal government's role in public health from the 1910s through the emergence of the CDC during World War II, I argue that national public health capacity emerged, to a great extent, out of the attempts of government officials to deal with the problem of tropical disease within the southern United States during periods of mobilization for war.
Consumption of ultra-processed foods and likely impact on human health. Evidence from Canada
Authors: Moubarac Jean-Claude , Martins Ana Paula Bortoletto , Claro Rafael Moreira , Levy Renata Bertazzi , Cannon Geoffrey , Monteiro Carlos Augusto
Published: November 2012

Objective

To investigate consumption of ultra-processed products in Canada and to assess their association with dietary quality.

Design

Application of a classification of foodstuffs based on the nature, extent and purpose of food processing to data from a national household food budget survey. Foods are classified as unprocessed/minimally processed foods (Group 1), processed culinary ingredients (Group 2) or ultra-processed products (Group 3).

Setting

All provinces and territories of Canada, 2001.

Subjects

Households (n 5643).

Results

Food purchases provided a mean per capita energy availability of 8908 (se 81) kJ/d (2129 (se 19) kcal/d). Over 61·7 % of dietary energy came from ultra-processed products (Group 3), 25·6 % from Group 1 and 12·7 % from Group 2. The overall diet exceeded WHO upper limits for fat, saturated fat, free sugars and Na density, with less fibre than recommended. It also exceeded the average energy density target of the World Cancer Research Fund/American Institute for Cancer Research. Group 3 products taken together are more fatty, sugary, salty and energy-dense than a combination of Group 1 and Group 2 items. Only the 20 % lowest consumers of ultra-processed products (who consumed 33·2 % of energy from these products) were anywhere near reaching all nutrient goals for the prevention of obesity and chronic non-communicable diseases.

Conclusions

The 2001 Canadian diet was dominated by ultra-processed products. As a group, these products are unhealthy. The present analysis indicates that any substantial improvement of the diet would involve much lower consumption of ultra-processed products and much higher consumption of meals and dishes prepared from minimally processed foods and processed culinary ingredients.
Up-regulation of nicotinic acetylcholine receptors in menthol cigarette smokers
Authors: Brody Arthur L. , Mukhin Alexey G. , La Charite Jaime , Ta Karen , Farahi Judah , Sugar Catherine A. , Mamoun Michael S. , Vellios Evan , Archie Meena , Kozman Maggie , Phuong Jonathan , Arlorio Franca , Mandelkern Mark A.
Published: November 2012

One-third of smokers primarily use menthol cigarettes and usage of these cigarettes leads to elevated serum nicotine levels and more difficulty quitting in standard treatment programmes. Previous brain imaging studies demonstrate that smoking (without regard to cigarette type) leads to up-regulation of β2*-containing nicotinic acetylcholine receptors (nAChRs). We sought to determine if menthol cigarette usage results in greater nAChR up-regulation than non-menthol cigarette usage. Altogether, 114 participants (22 menthol cigarette smokers, 41 non-menthol cigarette smokers and 51 non-smokers) underwent positron emission tomography scanning using the α4β2* nAChR radioligand 2-[18F]fluoro-A-85380 (2-FA). In comparing menthol to non-menthol cigarette smokers, an overall test of 2-FA total volume of distribution values revealed a significant between-group difference, resulting from menthol smokers having 9–28% higher α4β2* nAChR densities than non-menthol smokers across regions. In comparing the entire group of smokers to non-smokers, an overall test revealed a significant between-group difference, resulting from smokers having higher α4β2* nAChR levels in all regions studied (36–42%) other than thalamus (3%). Study results demonstrate that menthol smokers have greater up-regulation of nAChRs than non-menthol smokers. This difference is presumably related to higher nicotine exposure in menthol smokers, although other mechanisms for menthol influencing receptor density are possible. These results provide additional information about the severity of menthol cigarette use and may help explain why these smokers have more trouble quitting in standard treatment programmes.
Antipsychotic compounds differentially modulate high-frequency oscillations in the rat nucleus accumbens: a comparison of first- and second-generation drugs
Authors: Olszewski Maciej , Piasecka Joanna , Goda Sailaja A. , Kasicki Stefan , Hunt Mark J.
Published: November 2012

Improved understanding of the actions of antipsychotic compounds is critical for a better treatment of schizophrenia. Abnormal oscillatory activity has been found in schizophrenia and in rat models of the disease. N-Methyl-d-aspartic acid receptor (NMDAR) antagonists, used to model certain features of schizophrenia, increase the frequency and power of high-frequency oscillations (HFO, 130–180 Hz) in the rat nucleus accumbens, a brain region implicated in schizophrenia pathology. Antipsychotics can be classified as first- and second-generation drugs, the latter often reported to have wider benefit in humans and experimental models. This prompted the authors to examine the pre- and post-treatment effects of clozapine, risperidone (second-generation drugs) and sulpiride and haloperidol (first-generation drugs) on ketamine and MK801-enhanced accumbal HFO. Both NMDAR antagonists increased HFO frequency. In contrast, clozapine and risperidone markedly and dose-dependently reduced the frequency of spontaneous and NMDAR-antagonist-enhanced HFO, whilst a moderate effect was found for sulpiride and a much weaker effect for haloperidol. Unexpectedly, we found reductions in HFO frequency were associated with an increase in its power. These findings indicate that modulation of accumbal HFO frequency may be a fundamental effect produced by antipsychotic compounds. Of the drugs investigated, first- and second-generation compounds could be dissociated by their potency on this measure. This effect may partially explain the differences in the clinical profile of these drugs.
Deliberative inclusion of minorities: patterns of reciprocity among linguistic groups in Switzerland
Authors: Pedrini Seraina , Bächtiger André , Steenbergen Marco R.
Published: November 2012

We present a model of deliberative inclusion, focusing on reciprocity in the interaction between structural minorities/disadvantaged groups and majorities/privileged groups. Our model, however, comes with a ‘friendly amendment’: we have put the ‘burden of reciprocity’ mainly on majorities and privileged groups. It is mainly their obligation to seriously listen and respond to the demands and arguments of minorities and disadvantaged groups and show a willingness to respect and accommodate these interests. Empirically, we apply our model to the interaction of linguistic groups in the Swiss parliament. We find a highly egalitarian, sometimes even minority-favoring mode of interaction between the German-speaking majority and linguistic minorities. The German-speaking majority seems to be willing to take the ‘burden of reciprocity’ when linguistic minorities’ vital interests are concerned. Conversely, linguistic minorities are slightly more self-referential and adversarial under such conditions.
How Does the Inclusion of Twins Conceived via Fertility Treatments Influence the Results of Twin Studies?
Authors: Burt S. Alexandra , Klump Kelly L.
Published: November 2012

Rates of twinning have risen dramatically over the last 30 years, from 1 in 53 births in 1980 to 1 in 30 births in 2009 (Martin et al. (January 2012). Three decades of twin births in the United States, 1980–2009. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Health Statistics). This increase is largely attributable to increases in the use of fertility treatments (i.e., ovulation induction and in vitro fertilization) combined with delays in parenthood. Although this increase means that more twins are available for recruitment into twin studies, it also has potential consequences for the heritability estimates obtained in these studies. This study sought to evaluate this possibility, making use of the ongoing Michigan Twins Project (N = 7,261 families with twins aged 3–17 years), an arm of the Michigan State University Twin Registry. Results revealed that, on average, twins conceived via fertility treatments had lower rates of behavior problems than those conceived naturally, although these behavioral differences could be explained largely by demographic and socio-economic differences across the two types of twin families. Twin similarity did not meaningfully differ across fertility treatment status. We thus conclude that estimates of genetic and environmental influences obtained from twin studies over the last 10–15 years are more or less unaffected by the inclusion of twins conceived via fertility treatments in their samples.
Local deformations around volcanoes associated with the 2011 off the Pacific coast of Tohoku earthquake
Authors: Ozawa T. , Fujita E.
Published: November 2012

An Mw 9.0 great earthquake struck northeast Japan on 11 March 2011, causing crustal deformation of 1 to 2 m in volcanic areas. We applied synthetic aperture radar interferometry using Phased Array type L‐band Synthetic Aperture Radar on the ALOS satellite to investigate local deformation around volcanoes associated with the earthquake. We estimated the fault‐slip distribution along the trough based on obtained interferograms and crustal deformation from GEONET, and the estimated fault model explained the observed coseismic deformations well. The residual suggested local deformation around the Akita‐Komagatake, Kurikoma, Zao, Azuma, and Nasu volcanoes. Their deformations were obtained from independent synthetic aperture radar pairs. Additionally, deformations in the Kurikoma, Zao, and Azuma volcanoes were confirmed by GEONET data (no GEONET stations are located in the deformation areas of other volcanoes). These facts indicate that the obtained local deformations must be actual deformations, rather than noise. Our hypothesis is that coseismic extensional deformation concentrates in the soft medium under a volcano (e.g., magma and its surrounding rock) and that this deformation has caused local deformation with subsidence. To validate this hypothesis, we carried out numerical experiments using the finite element method for a soft medium under a volcano. Distributions of observed local deformations stretch in the direction of the minor principal axis of strain, and such distributions were obtained in this experiment, indicating that the hypothesis is plausible. Conceivably, such a concentration of coseismic deformation in a magma chamber may induce a volcanic eruption.
Evaluating model structure adequacy: The case of the Maggia Valley groundwater system, southern Switzerland
Authors: Foglia L. , Mehl S. W. , Hill M. C. , Burlando P.
Published: November 2012

Key Points

Predictions from alternative models is advised

Criteria do not consistently identify more accurate models

Results expected to be generally applicable to environmental models
What is the role of the observational dataset in the evaluation and scoring of climate models?
Authors: Gómez‐Navarro J. J. , Montávez J. P. , Jerez S. , Jiménez‐Guerrero P. , Zorita E.
Published: November 2012

Climate models are usually assessed through their capacity to reproduce present climate conditions, which in turn are established by comparing the output of climate simulations with observational data sets including gridded products. However, due to the nature of the procedures to obtain observations and the statistical techniques employed to extrapolate this information onto reference gridded databases, they contain important uncertainties which may compromise the evaluation process. This paper examines to what extent the evaluation and ranking of an ensemble of regional climate models, according to their ability to reproduce the observed climatologies, is sensitive to the choice of the reference observational data set. Results show that even in areas covered by dense monitoring networks such as Spain, uncertainties in the observations are comparable to the uncertainties within state‐of‐the‐art Regional Climate Models, at least when they are driven by nominally perfect boundary conditions like reanalysis. These findings point out that model evaluation should take into account the observational uncertainties. In particular, weighting models according to how well they perform with respect to a unique observation dataset, without acknowledging uncertainties in the observational dataset, might reduce the quality of the weighted ensemble average.
Chaos and irregularity in karst percolation
Authors: Mariethoz Gregoire , Baker Andy , Sivakumar Bellie , Hartland Adam , Graham Peter
Published: November 2012

This paper focuses on analyzing chaos in cave percolation water drip rates, which has implications for flow routing in fractured media and on the use of speleothems for paleoclimate reconstructions. It has been shown that the physics of dripping faucets involve a set of non‐linear equations leading to chaotic drip rate, meaning that, for a given drip rate, the interval between individual drops can vary greatly. It can be expected that drip waters supplying stalagmites show similar properties, and consequently the dependency between water flux and stalagmite growth rate or geochemistry could be more complicated than usually assumed. We used high‐frequency monitoring of two contrasting drips in a cave in Australia, and identified chaos in cave drip rate. Our findings also indicate that the occurrence of chaos can give insights into flow routing in fractured media.
Earthquake sound perception
Authors: Tosi Patrizia , Sbarra Paola , De Rubeis Valerio
Published: November 2012

Sound is an effect produced by almost all earthquakes. Using a web‐based questionnaire on earthquake effects that included questions relating to seismic sound, we collected 77,000 responses for recent shallow Italian earthquakes. An analysis of audibility attenuation indicated that the decrease of the percentage of respondents hearing the sound was proportional to the logarithm of the epicentral distance and linearly dependent on earthquake magnitude, in accordance with the behavior of ground displacement. Even if this result was based on Italian data, qualitative agreement with the results of theoretical displacement, and of a similar study based on French seismicity suggests wider validity. We also found that, given earthquake magnitude, audibility increased together with the observed macroseismic intensity, leading to the possibility of accounting for sound audibility in intensity assessment. Magnitude influenced this behavior, making small events easier to recognize, as suggested by their frequency content.
Periodicities of polar cap patches
Authors: Hosokawa K. , Taguchi S. , Ogawa Y. , Aoki T.
Published: November 2012

A highly sensitive all‐sky electron multiplier charge‐coupled device airglow imager has been operative in Longyearbyen, Norway since October 2011. The imager captures 630.0 nm all‐sky images with an exposure time of 4 s, which is about 10 times shorter than that achieved by conventional cooled CCD imagers. This allows us to visualize the structure of polar cap patches without blurring effects and better estimate their periodicities. We present, as one of the first results from the imager, an event of successive appearance of patches on the night of 21 December 2011. A time series of the optical intensity at zenith showed modulations having two distinguished periods, one at 40 min and the other at 5–12 min. One possible explanation is that such a coexistence of two different periodicities is a manifestation of simultaneous occurrence of patch generation processes on the 40 min periodicity was created by large‐scale reconfiguration of the dayside convection pattern while the 5–12 min modulations were closely associated with mechanisms driven by pulsed reconnection on the dayside magnetopause. Such a combined effect of multiple patch generation processes may play a role in structuring patches; thus, it would be of particular importance for evaluating the space weather effects in the trans‐ionospheric communications environment in the polar cap.
Application of satellite observations for identifying regions of dominant sources of nitrogen oxides over the Indian Subcontinent
Authors: Ghude Sachin D. , Kulkarni Santosh H. , Jena Chinmay , Pfister Gabriele G. , Beig G. , Fadnavis S. , van der A R. J.
Published: November 2012

We used SCIAMACHY (10:00 LT) and OMI (13:30 LT) tropospheric NO2columns to study diurnal and seasonal patterns in NO2concentrations over India. Using characteristics of seasonal variability in tropospheric NO2columns, we present a simple methodology to identify the dominant NOx source category for specific regions in India. Regions where the dominant source category is classified as biomass burning are found generally to agree with the ATSR fire count distribution. Relating OMI NO2columns to surface NOx emission, we find that biomass burning emission account for an average flux of 1.55 × 1011molecules cm−2 s−1during the peak burning period. Furthermore, extrapolating this estimated flux to the total burned area for the year 2005, biomass burning is estimated to account for 72 Gg of N emissions. Additional analysis of fire events in Northeast India shows a marked increase in TES retrieved O3concentrations, suggesting significant photochemical ozone formation during the peak biomass burning period. Regions where the dominant source type was categorized as anthropogenic are in good agreement with the distribution of major industrial regions and urban centers in India. Tropospheric NO2columns over these anthropogenic source regions increased by 3.8% per year between 2003 and 2011, which is consistent with the growth in oil and coal consumption in India. The OMI‐derived surface NO2mixing ratios are indirectly validated with the surface in situ measurements (correlation r = 0.85, n = 88) obtained from the air quality monitoring network in Delhi during August 2010 to January 2011. Most of the OMI‐derived surface NO2values agree with surface‐based measurements, supporting the direct utility of OMI observation for emission estimates. Finally, we use OMI NO2columns to estimate NOx emissions for selected large cites and major thermal power plants in India and compare these estimates with the INTEX‐B and EDGAR emission inventory. We find that, for a few locations, OMI‐derived emission show fair agreement; however, for many locations, NOx emissions differ from INTEX‐B and EDGAR inventories.
Nowcasting severe convective activity over southeast India using ground‐based microwave radiometer observations
Authors: Madhulatha A. , Rajeevan M. , Venkat Ratnam M. , Bhate Jyoti , Naidu C. V.
Published: November 2012

In the present study, the feasibility of nowcasting convective activity is examined by using thermodynamic indices derived from the ground‐based microwave radiometer (MWR) observations located at a tropical station, Gadanki (13.5°N, 79.2°E). There is a good comparison between thermodynamic parameters derived from MWR and colocated GPS radiosonde observations, indicating that MWR observations can be used to develop techniques for nowcasting severe convective activity. Using MWR observations, a nowcasting technique was developed with the data of 26 thunderstorm cases observed at Gadanki. The analysis showed that there are sharp changes in some thermodynamic indices, such as the K index, the humidity index, precipitable water content, the stability index, and equivalent potential temperature lapse rates, about 2–4 h before the occurrence of thunderstorm. A superepoch analysis was made to examine the composite temporal variations of the thermodynamic indices associated with the occurrence of thunderstorms. The superepoch analysis revealed that 2–4 h prior to the storm occurrence, appreciable variations in many parameters are observed, suggesting thermodynamic evolution of the boundary layer convective instability. It is further demonstrated that by monitoring these variations it is possible to predict the ensuing thunderstorm activity over the region at least 2 h in advance. The association between the temporal evolution of thermodynamic indices and convective activity has been tested for the independent case of nine thunderstorms. The present results suggest that ground‐based MWR observations can be used effectively to predict the occurrence of thunderstorms at least 2 h in advance.
Evaluating and understanding top of the atmosphere cloud radiative effects in Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) Coupled Model Intercomparison Project Phase 5 (CMIP5) models using satellite observations
Authors: Wang Hailan , Su Wenying
Published: November 2012

In this study, the annual mean climatology of top of the atmosphere (TOA) shortwave and longwave cloud radiative effects in 12 Atmospheric Model Intercomparison Project (AMIP)‐type simulations participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) is evaluated and investigated using satellite‐based observations, with a focus on the tropics. Results show that the CMIP5 AMIPs simulate large‐scale regional mean TOA radiative fluxes and cloud radiative forcings (CRFs) well but produce considerably less cloud amount, particularly in the middle and lower troposphere. The good model simulations in tropical means, with multimodel mean biases of ‐3.6 W/m2 for shortwave CRF and ‐1.0 W/m2 for longwave CRF, are, however, a result of compensating errors over different dynamical regimes. Over the Maritime Continent, most of the models simulate moderately less high‐cloud fraction, leading to weaker shortwave cooling and longwave warming and a larger net cooling. Over subtropical strong subsidence regimes, most of the CMIP5 models strongly underestimate stratocumulus cloud amount and show considerably weaker local shortwave CRF. Over the transitional trade cumulus regimes, a notable feature is that while at varying amplitudes, most of the CMIP5 models consistently simulate a deeper and drier boundary layer, more moist free troposphere, and more high clouds and, consequently, overestimate shortwave cooling and longwave warming effects there. While most of the CMIP5 models show the same sign as the multimodel mean, there are substantial model spreads, particularly over the tropical deep convective and subtropical strong subsidence regimes. Representing clouds and their TOA radiative effects remains a challenge in the CMIP5 models.
Thermal model for analysis of Mars infrared mapping
Authors: Kieffer Hugh H.
Published: November 2012

The KRC numerical thermal model has been used in the analysis of observations from virtually all Mars missions with infrared sensors and for the selection of virtually all Mars' landing sites. It uses a physics‐based one‐layer atmosphere gray at solar and thermal wavelengths to determine the radiative effect of a dusty atmosphere. One gas component may condense to form a seasonal polar cap and affect the global surface pressure. The atmosphere may be omitted entirely to model airless bodies. KRC uses layers that become thicker geometrically with depth and it uses repeated time step doubling. The surface may be homogeneous or have two zones of material properties, each zone may have temperature‐dependent thermal conductivity and specific heat. Surface slopes or depressions are modeled to first order. Here KRC is described in detail and used to compute globally the annual average surface temperature accounting for albedo, thermal inertia, elevation, slope at 3 km resolution, and zonal climate. Comparisons with three other thermal models are discussed. The model is available for general use.
Brain Magnetic Resonance Spectroscopy in Episodic Hepatic Encephalopathy
Authors: Chavarria Laia , Alonso Juli , García-Martínez Rita , Simón-Talero Macarena , Ventura-Cots Meritxell , Ramírez Clara , Torrens Maria , Vargas Víctor , Rovira Alex , Córdoba Juan
Published: November 2012

Brain magnetic resonance (MR) study has shown metabolic abnormalities and changes in water distribution of the brain tissue that may relate to the pathogenesis of hepatic encephalopathy (HE). We designed a study to investigate the disturbances in brain water and metabolites during episodic HE using a 3-T MR scanner. Cirrhotic patients with different grades of HE underwent MR during hospitalization ( n = 18). The MR was repeated at 6 weeks' follow-up ( n = 14). The results were compared with those of a group of healthy volunteers ( n = 8). During episodic HE, brain diffusion-weighted imaging showed a high apparent diffusion coefficient (ADC) (12% to 14%) that decreased during follow-up (–1% to −4%). These disturbances were accompanied by high glutamine (581%), low choline (–31%), and low myo-inositol (–86%) peaks on MR spectroscopy. In overt HE, patients showed high glutamine that decreased during follow-up (–22%). In addition, these patients exhibited a rise in plasma S100 beta and enlargement of brain white-matter lesions. In conclusion, several disturbances detected by MR support the presence of impaired brain water homeostasis during episodic HE. Although astrocytes have a major role in this condition, brain edema during episodic HE may be extracellular and does not appear to be directly responsible for the development of neurologic manifestations.
Multiscale Kinetic Modeling of Liposomal Doxorubicin Delivery Quantifies the Role of Tumor and Drug‐Specific Parameters in Local Delivery to Tumors
Authors: Hendriks BS , Reynolds JG , Klinz SG , Geretti E , Lee H , Leonard SC , Gaddy DF , Espelin CW , Nielsen UB , Wickham TJ
Published: November 2012

Nanoparticle encapsulation has been used as a means to manipulate the pharmacokinetic (PK) and safety profile of drugs in oncology. Using pegylated liposomal doxorubicin (PLD) vs. conventional doxorubicin as a model system, we developed and experimentally validated a multiscale computational model of liposomal drug delivery. We demonstrated that, for varying tumor transport properties, there is a regimen where liposomal and conventional doxorubicin deliver identical amounts of doxorubicin to tumor cell nuclei. In mice, typical tumor properties consistently favor improved delivery via liposomes relative to free drug. However, in humans, we predict that some tumors will have properties wherein liposomal delivery delivers the identical amount of drug to its target relative to dosing with free drug. The ability to identify tumor types and/or individual patient tumors with high degree of liposome deposition may be critical for optimizing the success of nanoparticle and liposomal anticancer therapeutics.

CPT: Pharmacometrics & Systems Pharmacology (2012) 1, e15; doi:10.1038/psp.2012.16; advance online publication 21 November 2012
C-terminal low-complexity sequence repeats of Mycobacterium smegmatis Ku modulate DNA binding
Authors: Kushwaha Ambuj K. , Grove Anne
Published: November 2012

Ku protein is an integral component of the NHEJ (non-homologous end-joining) pathway of DSB (double-strand break) repair. Both eukaryotic and prokaryotic Ku homologues have been characterized and shown to bind DNA ends. A unique feature of Mycobacterium smegmatis Ku is its basic C-terminal tail that contains several lysine-rich low-complexity PAKKA repeats that are absent from homologues encoded by obligate parasitic mycobacteria. Such PAKKA repeats are also characteristic of mycobacterial Hlp (histone-like protein) for which they have been shown to confer the ability to appose DNA ends. Unexpectedly, removal of the lysine-rich extension enhances DNA-binding affinity, but an interaction between DNA and the PAKKA repeats is indicated by the observation that only full-length Ku forms multiple complexes with a short stem-loop-containing DNA previously designed to accommodate only one Ku dimer. The C-terminal extension promotes DNA end-joining by T4 DNA ligase, suggesting that the PAKKA repeats also contribute to efficient end-joining. We suggest that low-complexity lysine-rich sequences have evolved repeatedly to modulate the function of unrelated DNA-binding proteins.
Temperature dependence of magnetic anisotropy constant in iron chalcogenide Fe3Se4: Excellent agreement with theories
Authors: Wang Jun , Duan Hongyan , Lin Xiong , Aguilar Victor , Mosqueda Aaron , Zhao Guo-meng
Published: November 2012

Magnetic hysteresis loops were measured for ferrimagnetic iron chalcogenide Fe3Se4 nanoparticles in the whole temperature range below the Curie temperature TC (315 K). The coercivity of the material is huge, reaching about 40 kOe at 10 K. The magnetic anisotropy constant K was determined from the magnetic hysteresis loop using the law of approach to saturation. The deduced anisotropy constant at 10 K is 5.22×106 erg/cm3, which is over one order of magnitude larger than that of Fe3O4. We also demonstrated that the experimental magnetic hysteresis loop is in good agreement with the theoretical curve calculated by Stoner and Wohlfarth for a noninteracting randomly oriented uniaxial single-domain particle system. Moreover, we show that K is proportional to the cube of the saturation magnetization Ms, which confirms earlier theoretical models for uniaxial magnets.
Parametric study of the frequency-domain thermoreflectance technique
Authors: Xing C. , Jensen C. , Hua Z. , Ban H. , Hurley D. H. , Khafizov M. , Kennedy J. R.
Published: November 2012

Without requiring regression for parameter determination, one-dimensional (1D) analytical models are used by many research groups to extract the thermal properties in frequency-domain thermoreflectance measurements. Experimentally, this approach involves heating the sample with a pump laser and probing the temperature response with spatially coincident probe laser. Micron order lateral resolution can be obtained by tightly focusing the pump and probe lasers. However, small laser beam spot sizes necessarily bring into question the assumptions associated with 1D analytical models. In this study, we analyzed the applicability of 1D analytical models by comparing to 2D analytical and fully numerical models. Specifically, we considered a generic n-layer two-dimensional (2D), axisymmetric analytical model including effects of volumetric heat absorption, contact resistance, and anisotropic properties. In addition, a finite element numerical model was employed to consider nonlinear effects caused by temperature dependent thermal conductivity. Nonlinearity is of germane importance to frequency domain approaches because the experimental geometry is such that the probe is always sensing the maximum temperature fluctuation. To quantify the applicability of the 1D model, parametric studies were performed considering the effects of: film thickness, heating laser size, probe laser size, substrate-to-film effusivity ratio, interfacial thermal resistance between layers, volumetric heating, substrate thermal conductivity, nonlinear boundary conditions, and anisotropic and temperature dependent thermal conductivity.
Temperature-dependent relaxation current on single and dual layer Pt metal nanocrystal-based Al2O3/SiO2 gate stack
Authors: Chen Y. N. , Goh K. E. J. , Wu X. , Lwin Z. Z. , Singh P. K. , Mahapatra S. , Pey K. L.
Published: November 2012

We present a systematic investigation of the temperature dependent relaxation current behavior for single layer and dual layer Pt metal nanocrystal (MNC)-based Al2O3/SiO2 flash memory gate stacks. Stacks containing single layer Pt MNC exhibit a dual-slope behavior in the log-log plots of the relaxation transient, whereas those with dual layer Pt MNC exhibit a single-slope behavior. We propose a physical model embodying two competing relaxation mechanisms to explain the Pt MNC induced relaxation current—thermionic emission and the quantum tunneling. Based on this model, the dual-slope behavior of single layer MNC-based gate stack can be ascribed to the dominance of thermionic emission at the initial part and quantum tunneling at the tail part. In contrast, the single slope behavior of the dual layer metal nanocrystal-based stack arises from the dominance of the quantum tunneling throughout the relaxation. In addition, we verify that stacks containing dual layer MNC show better retention property than their single layer counterparts. Our results demonstrate that relaxation current measurements offer a simple way to assess the charge retention capability for MNC-based gate stacks.
Simulation of metal-semiconductor-metal devices on heavily compensated Cd0.9Zn0.1Te
Authors: Ruzin A.
Published: November 2012

This study focuses on finite-element calculations of the electrical properties of metal-semiconductor-metal devices processed on heavily compensated, high resistivity, Cd0.9Zn0.1Te crystals. Deep and shallow levels used in the calculations were taken from published experimental results. Several compensation configurations, yielding similar resistivities were investigated. The capture cross-sections of the deep traps were introduced as an additional parameter. It is shown that with pure-Ohmic contacts the characteristics of Metal-Semiconductor-Metal devices are similar to the non-compensated case. With Schottky contacts it is shown that the device characteristics greatly depend on the compensation level and on capture cross section, yielding anything from Ohmic-like behavior to Schottky-like characteristics. Furthermore, it is shown that Schottky contacts and rectifying I-V behavior do not imply classical Schottky electric field and space charge distributions.
Terahertz spinplasmonics in random ensembles of Ni and Co microparticles
Authors: Straatsma C. J. E. , Johnson M. , Elezzabi A. Y.
Published: November 2012

Terahertz time-domain spectroscopy has found widespread application due to a number of attractive features including phase-sensitive detection and subpicosecond temporal resolution. Recently, the application of this technique to study ensembles of sub-wavelength ferromagnetic particles resulted in the observation of novel and unusual effects. The shape, relative transmission amplitude, and time delay of a broadband terahertz waveform were sensitive to the magnitude and direction of an applied magnetic field and to the magnetization states of the particles. Furthermore, the addition of a thin coating of nonmagnetic metal (Au) at the surface of the particles had a profound effect on these characteristics. To better understand the new phenomena, a terahertz time-domain spectroscopy investigation of ensembles of ferromagnetic particles is presented in which the test range of magnetic field is extended, including significantly larger magnitude as well as both field polarities. By sweeping the applied field continuously through zero, hysteretic effects are now observed. Furthermore, we show that the effects of a thin nonmagnetic metal coating are not unique to Au. These effects are also observed in particle ensembles in which the ferromagnetic particles are coated with thin Al or Ag films.
Passivation of Zn3P2 substrates by aqueous chemical etching and air oxidation
Authors: Kimball Gregory M. , Bosco Jeffrey P. , Müller Astrid M. , Tajdar Syed F. , Brunschwig Bruce S. , Atwater Harry A. , Lewis Nathan S.
Published: November 2012

Surface recombination velocities measured by time-resolved photoluminescence and compositions of Zn3P2 surfaces measured by x-ray photoelectron spectroscopy (XPS) have been correlated for a series of wet chemical etches of Zn3P2 substrates. Zn3P2 substrates that were etched with Br2 in methanol exhibited surface recombination velocity values of 2.8 × 104 cm s−1, whereas substrates that were further treated by aqueous HF–H2O2 exhibited surface recombination velocity values of 1.0 × 104 cm s−1. Zn3P2 substrates that were etched with Br2 in methanol and exposed to air for 1 week exhibited surface recombination velocity values of 1.8 × 103 cm s−1, as well as improved ideality in metal/insulator/semiconductor devices.
Microstructure and vacancy-type defects of high-pressure torsion deformed Al-3 wt%Cu alloy
Authors: Parz Peter , Faller Michael , Pippan Reinhard , Reingruber Herbert , Puff Werner , Würschum Roland
Published: November 2012

The influence of high-pressure torsion (HPT) on the microstructure and free-volume type defects of supersaturated Al-3 wt%Cu was studied. By means of HPT, grain refinement down to sizes of 100 nm could be achieved. Positron annihilation spectroscopy was applied for the characterization of deformation-induced defects and of vacancy-solute interaction. The chemical sensitive method of two-dimensional Doppler broadening spectroscopy reveals predominantly deformation-induced defects. In comparison to undeformed supersaturated Al-3 wt%Cu, the fraction of Cu-decorated free-volume type defects is strongly reduced and Al2Cu-precipitates with equilibrium structure occur rather than metastable semi-coherent Al-Cu precipitates. These precipitates stabilize the nanocrystalline structure and give rise to a rather different aging behaviour compared to the undeformed state.