bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Bayesian Approach to Parameter Estimation for Kernel Density Estimation via Transformations
Authors: Liu Qing , Pitt David , Zhang Xibin , Wu Xueyuan 
Published: April 2011

AbstractIn this paper, we present a Markov chain Monte Carlo (MCMC) simulation algorithm for estimating parameters in the kernel density estimation of bivariate insurance claim data via transformations. Our data set consists of two types of auto insurance claim costs and exhibits a high-level of skewness in the marginal empirical distributions. Therefore, the kernel density estimator based on original data does not perform well. However, the density of the original data can be estimated through estimating the density of the transformed data using kernels. It is well known that the performance of a kernel density estimator is mainly determined by the bandwidth, and only in a minor way by the kernel. In the current literature, there have been some developments in the area of estimating densities based on transformed data, where bandwidth selection usually depends on pre-determined transformation parameters. Moreover, in the bivariate situation, the transformation parameters were estimated for each dimension individually. We use a Bayesian sampling algorithm and present a Metropolis-Hastings sampling procedure to sample the bandwidth and transformation parameters from their posterior density. Our contribution is to estimate the bandwidths and transformation parameters simultaneously within a Metropolis-Hastings sampling procedure. Moreover, we demonstrate that the correlation between the two dimensions is better captured through the bivariate density estimator based on transformed data.
First Report of Pseudoperonospora cubensis on Cucurbita moschata in the Czech Republic
Authors: Pavelková J. , Lebeda A. , Sedláková B. 
Published: April 2011

Pseudoperonospora cubensis (Berk. & M.A. Curtis) Rostovzev, the causal agent of cucurbit downy mildew, was observed for the first time on Cucurbita moschata Duchesne in the Czech Republic (CR) in August 2009 and repeatedly in September 2010. Recently, C. moschata has not been an economically important crop in the CR; however, related crops C. pepo and C. maxima have increased in importance. Infected plants with P. cubensis were found in two locations: in a hobby garden in north Moravia (Nový Jičín – Kojetín [49°33′48.088″N, 17°59′16.632″E], 2009 and 2010) and in a commercial field in central Moravia (Olomouc-Holice [49°34′31.95″N, 17°17′35.462″E], 2010). The pathogen caused small, angular, yellowish or pale green lesions on the upper leaf surfaces and produced sporangiophores and sporangia on the lower leaf surfaces. The lesions were delimited by leaf veins and later turned necrotic. Sporangiophores were hyaline, branched, and emerged in groups from stomata. Olive brown-to-dark brown sporangia were ellipsoidal to oblong. Our morphological observations confirmed that the pathogen was P. cubensis (2). No previous reports are available of P. cubensis on C. moschata in CR or anywhere in Central Europe. However, P. cubensis is common on C. moschata in some parts of Asia and the United States (1,2). P. cubensis exhibiting clear host specialization has been reported in different countries and geographic areas (2). A C. moschata isolate (PC 88/2009) originating from the naturally infected plants was inoculated (1 × 105 spores per ml and incubation temperature of 18/15°C during light/dark cycles) according to the methodology described by Lebeda and Urban (3) onto the abaxial surface of leaf discs of all genotypes of a differential set of cucurbits for P. cubensis pathotype determination (4). C. moschata (line Novo5, Nohel-Garden, CR) was added to this set. The isolate PC 88/2009 was highly pathogenic to all screened Cucurbita spp. genotypes (C. pepo, C. maxima, and C. moschata). However, no infection was detected on most of the Cucumis accessions; only Cucumis melo subsp. agrestis var. conomon was susceptible. Also, no infection was observed on other differentials (Citrullus, Benincasa, Luffa, and Lagenaria). The pathotype was classified as Pc 4/15/0. This pathotype had not been previously detected in CR. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.arsgrin. gov/fungaldatabases/ . December 16, 2010. (2) A. Lebeda and Y. Cohen. Eur. J. Plant Pathol. 129:157, 2011. (3) A. Lebeda and J. Urban. Page 285 in: Mass Screening Techniques for Selecting Crops Resistant to Disease. M. M. Spencer and A. Lebeda, eds. International Atomic Energy Agency (IAEA), Vienna, Austria, 2010 (4) A. Lebeda and M. P. Widrlechner. J. Plant Dis. Protect. 110:337, 2003.
Global atmospheric methane: budget, changes and dangers
Authors: Dlugokencky Edward J. , Nisbet Euan G. , Fisher Rebecca , Lowry David 
Published: April 2011

A factor of 2.5 increase in the global abundance of atmospheric methane (CH
4
) since 1750 contributes 0.5 Wm
−2
to total direct radiative forcing by long-lived greenhouse gases (2.77 Wm
−2
in 2009), while its role in atmospheric chemistry adds another approximately 0.2 Wm
−2
of indirect forcing. Since CH
4
has a relatively short lifetime and it is very close to a steady state, reductions in its emissions would quickly benefit climate. Sensible emission mitigation strategies require quantitative understanding of CH
4
’s budget of emissions and sinks. Atmospheric observations of CH
4
abundance and its rate of increase, combined with an estimate of the CH
4
lifetime, constrain total global CH
4
emissions to between 500 and 600 Tg CH
4
yr
−1
. While total global emissions are constrained reasonably well, estimates of emissions by source sector vary by up to a factor of 2. Current observation networks are suitable to constrain emissions at large scales (e.g. global) but not at the regional to national scales necessary to verify emission reductions under emissions trading schemes. Improved constraints on the global CH
4
budget and its break down of emissions by source sector and country will come from an enhanced observation network for CH
4
abundance and its isotopic composition (
δ
13
C,
δ
D (D=
2
H) and
δ
14
C). Isotopic measurements are a valuable tool in distinguishing among various sources that contribute emissions to an air parcel, once fractionation by loss processes is accounted for. Isotopic measurements are especially useful at regional scales where signals are larger. Reducing emissions from many anthropogenic source sectors is cost-effective, but these gains may be cancelled, in part, by increasing emissions related to economic development in many parts of the world. An observation network that can quantitatively assess these changing emissions, both positive and negative, is required, especially in the context of emissions trading schemes.
The atmospheric signature of carbon capture and storage
Authors: Keeling Ralph F. , Manning Andrew C. , Dubey Manvendra K. 
Published: April 2011

Compared with other industrial processes, carbon capture and storage (CCS) will have an unusual impact on atmospheric composition by reducing the CO
2
released from fossil-fuel combustion plants, but not reducing the associated O
2
loss. CO
2
that leaks into the air from below-ground CCS sites will also be unusual in lacking the O
2
deficit normally associated with typical land CO
2
sources, such as from combustion or ecosystem exchanges. CCS may also produce distinct isotopic changes in atmospheric CO
2
. Using simple models and calculations, we estimate the impact of CCS or leakage on regional atmospheric composition. We also estimate the possible impact on global atmospheric composition, assuming that the technology is widely adopted. Because of its unique signature, CCS may be especially amenable to monitoring, both regionally and globally, using atmospheric observing systems. Measurements of the O
2
/N
2
ratio and the CO
2
concentration in the proximity of a CCS site may allow detection of point leaks of the order of 1000 ton CO
2
yr
−1
from a CCS reservoir up to 1 km from the source. Measurements of O
2
/N
2
and CO
2
in background air from a global network may allow quantification of global and hemispheric capture rates from CCS to the order of ±0.4 Pg C yr
−1
.
Awareness in children: a secondary analysis of five cohort studies
Authors: Davidson A. J. , Smith K. R. , Blussé van Oud‐Alblas H. J. , Lopez U. , Malviya S. , Bannister C. F. , Galinkin J. L. , Habre W. , Ironfield C. , Voepel‐Lewis T. , Weber F. 
Published: April 2011

SummaryFive recent cohort studies have shown a frequency of awareness in paediatric anaesthesia of between 0.2% and 1.2%, but they were not individually large enough to identify risk factors. This study pooled raw data from these five studies to identify factors associated with awareness in children. The outcome of awareness was taken as the cases judged to be most likely awareness cases in each study. Logistic regression was used to identify awareness‐associated factors. A combined sample of 4486 anaesthetics revealed 33 cases of awareness. Unadjusted analysis demonstrated weak evidence that nitrous oxide used as an anaesthetic maintenance adjunct was associated with awareness (OR 2.04 (95% CI 0.97–4.33), p = 0.06), and some evidence that use of a tracheal tube was associated with awareness (OR 2.78 (95% CI 1.11–6.94), p = 0.03). Multivariable regression analysis revealed that nitrous oxide maintenance and use of a tracheal tube were independently associated with awareness (nitrous oxide, OR 2.4 (95% CI 1.08–5.32), p = 0.03; tracheal tube, OR 3.0 (95% CI 1.20–7.56), p = 0.02).
A comparison of pressure‐controlled and volume‐controlled ventilation for laparoscopic cholecystectomy*
Authors: Tyagi A. , Kumar R. , Sethi A. K. , Mohta M. 
Published: April 2011

SummaryThe potential advantages of pressure‐controlled over volume‐controlled ventilation during laparoscopic surgery have yet to be proven. We randomly assigned 42 patients with BMI < 30 kg.m−2 scheduled for laparoscopic cholecystectomy to receive either pressure‐ or volume‐controlled ventilation. Compared with volume‐controlled ventilation, pressure‐controlled ventilation resulted in a significant decrease in mean (SD) peak airway pressure at 10 min (20.4 (2.7) vs 24.0 (4.7) cmH2O, p = 0.004) and 30 min (20.7 (3.0) vs 23.9 (4.9) cmH2O, p = 0.015) and an increase in mean airway pressure at 10 min (10.5 (0.9) vs 9.6 (1.1) cmH2O, p = 0.007) and 30 min (10.5 (1.1) vs 9.6 (1.2) cmH2O, p = 0.016) after the start of surgery. Gas exchange and haemodynamic stability were similar. We conclude that pressure‐controlled ventilation is a safe alternative and offers some advantages to volume‐controlled ventilation during laparoscopic cholecystectomy in non‐obese patients.
Road traffic accidents and psychotropic medication use in the Netherlands: a case–control study
Authors: Ravera Silvia , van Rein Nienke , de Gier Johan J. , de Jong‐van den Berg Lolkje T. W. 
Published: April 2011

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Some psychotropic medications (e.g. benzodiazepines, sedative antidepressants, etc.) can impair cognitive and psychomotor functions and, therefore, endanger traffic safety.• There is a lack of knowledge concerning the role in traffic safety of first and new generations of psychotropic medications, new and chronic users, young and old drivers, and polypharmacy. WHAT THIS STUDY ADDS • There is an increased risk of having a traffic accident after being exposed to some psychotropic medicine classes and, in particular, to SSRIs.• Health care professionals and patients should be properly informed about the potential effects of some psychoactive medications on driving abilities.• The role of SSRIs in traffic safety has to be investigated further.AIM To examine the association between the use of commonly prescribed psychotropic medications and road traffic accident risk.METHODS A record‐linkage database was used to perform a case–control study in the Netherlands. The data came from three sources: pharmacy prescription data, police traffic accident data and driving licence data. Cases were defined as drivers, who had a traffic accident that required medical assistance between 2000 and 2007. Controls were defined as adults, who had a driving licence and had no traffic accident during the study period. Four controls were matched for each case. The following psychotropic medicine groups were examined: antipsychotics, anxiolytics, hypnotics and sedatives, and antidepressants stratified in the two groups, SSRIs and other antidepressants. Various variables, such as age, gender, medicine half‐life and alcohol use, were considered for the analysis.RESULTS Three thousand nine hundred and sixty‐three cases and 18 828 controls were included in the case–control analysis. A significant association was found between traffic accident risk and exposure to anxiolytics (OR = 1.54, 95% CI 1.11, 2.15), and SSRIs (OR = 2.03, 95% CI 1.31, 3.14). A statistically significant increased risk was also seen in chronic anxiolytic users, females and young users (18 to 29 years old), chronic SSRI users, females and middle‐aged users (30 to 59 years old), and intermediate half‐life hypnotic users.CONCLUSIONS The results of this study support previous findings and confirm that psychoactive medications can constitute a problem in traffic safety. Both health care providers and patients should be properly informed of the potential risks associated with the use of these medicines.
Additional safety risk to exceptionally approved drugs in Europe?
Authors: Arnardottir Arna H. , Haaijer‐Ruskamp Flora M. , Straus Sabine M. J. , Eichler Hans‐Georg , de Graeff Pieter A. , Mol Peter G. M. 
Published: April 2011

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The safety profile of new drugs is not well known at the time of market approval and serious safety issues are regularly identified for marketed drugs.• Drugs intended to meet an unmet medical need can be approved for the market with less safety data than is usually required, using the Exceptional Circumstances and Conditional Approval applications in European Central procedure.• It is unknown whether for drugs approved using Exceptional Circumstances and Conditional Approval procedures have an increased probability of serious safety issues identified post approval than for drugs approved through the standard procedures. WHAT THIS STUDY ADDS • Using the Exceptional Circumstances and Conditional Approval procedures does not lead to more post‐marketing safety alerts or safety‐related withdrawals when used for drugs with unmet medical needs.AIMS Regulatory requirements for new drugs have increased. Special approval procedures with priority assessment are possible for drugs with clear ‘unmet medical need’. We question whether these Exceptional Circumstances (EC) or Conditional Approval (CA) procedures have led to a higher probability of serious safety issues.METHODS A retrospective cohort study was performed of new drugs approved in Europe between 1999 and 2009. The determinant was EC/CA vs. standard procedure approval. Outcome variables were frequency and timing of a first Direct Healthcare Professional Communication (DHPC). An association between approval procedure and the time from market approval to DHPC was assessed using Kaplan‐Meyer survival analysis and Cox‐regression to correct for covariates.RESULTS In total 289 new drugs were approved. Forty‐six (16.4%) were approved under EC or CA, of which seven received a DHPC (15%). This was similar to the standard approval drugs (243), of which 33 received one or more DHPC (14%, P= 0.77). The probability of acquiring a DHPC for standard approval drugs vs. EC/CA drugs during 11‐year follow‐up is 22% (95% CI 14%, 29%) and 26% (95% CI 8%, 44%), respectively (log‐rank P= 0.726). This difference remained not significant in the Cox‐regression model: hazard ratio 0.94 (95% CI 0.40, 2.20). Only drug type was identified as a confounding covariate.CONCLUSION The EC/CA procedure is not associated with a higher probability of DHPCs despite limited clinical development data. These data do not support the view that early drug approval increases the risk of serious safety issues emerging after market approval.
Aortic root ectasia in patients with acromegaly: experience at a single center
Authors: Casini Alessandra Ferri , Neto Leonardo Vieira , Fontes Rosita , França Rodrigo Fraguas , Xavier Sérgio Salles , Gadelha Mônica Roberto 
Published: April 2011

SummaryBackground  Acromegaly is associated with increased cardiovascular mortality, and increased aortic root diameter has been recently described in the literature as a possible feature of acromegalic cardiomyopathy.Objective  To assess the aortic root diameter and the prevalence of aortic ectasia in acromegalic patients.Patients and methods  This paper presents a transversal analysis of 42 acromegalic patients by Doppler echocardiogram and comparison with 42 age, sex, body surface area and hypertension matched controls.Results  The mean aortic root diameter at the level of the aortic leaflets was increased in acromegalic patients when compared to controls (3·4 ± 0·5 vs 2·9 ± 0·4 cm, respectively, P < 0·0001). The aortic root diameter was significantly greater in men than in women (3·6 ± 0·6 cm vs 3·2 ± 0·4 cm, respectively, P = 0·004), and the left ventricular mass index was positively correlated with the diameter of the aorta (r = 0·37, P = 0·01). Using a cut‐off point ≥ 3·8 cm, an aortic ectasia prevalence of 26·1 vs 2·3% was found in acromegalic patients and controls, respectively (P = 0·002). Only acromegaly was associated with aortic ectasia (P = 0·01).Conclusion  The aortic root diameter was higher, and the prevalence of aortic ectasia was more common in acromegalic patients than in controls. In addition, only acromegalic disease was associated with aortic ectasia, suggesting the direct effects of GH and insulin‐like growth factor‐I excess on the cardiovascular system.
The dksA promoter is negatively feedback regulated by DksA and ppGpp
Authors: Chandrangsu Pete , Lemke Justin J. , Gourse Richard L. 
Published: April 2011

Summary Escherichia coli DksA is an RNA polymerase (RNAP)‐binding protein required for the regulation of a number of promoters, including those for the biosynthesis of rRNA, many ribosomal proteins, components of the flagellum, and several amino acids. Previous work demonstrated that DksA protein levels do not vary greatly in different growth conditions. We show here that DksA is a stable protein whose levels are kept constant by a negative feedback loop in which transcription from the dksA promoter is inhibited by DksA protein in conjunction with its cofactor ppGpp. We map the primary dksA promoter by primer extension, show that its activity increases in a strain lacking DksA, that the DksA protein accumulates when expressed from an exogenous promoter, that inhibition of transcription by DksA is direct since it occurs with purified components in vitro, and that inhibition correlates with effects of DksA on the lifetime of the dksA promoter complex. This work provides a mechanistic basis for the maintenance of constant cellular levels of DksA in E. coli and supports the model that transcription regulation by ppGpp/DksA derives from fluctuations in the concentrations of the small molecule cofactor rather than of DksA itself.
Influence of cultivar resistance and inoculum density on root hair infection of canola (Brassica napus) by Plasmodiophora brassicae
Authors: Hwang S. F. , Ahmed H. U. , Zhou Q. , Strelkov S. E. , Gossen B. D. , Peng G. , Turnbull G. D. 
Published: April 2011

The impact of cultivar resistance and inoculum density on the incidence of primary infection of canola root hairs by Plasmodiophora brassicae, the causal agent of clubroot, was assessed by microscopy. The incidence of root hair infection in both a resistant and a susceptible cultivar increased with increasing inoculum density, but was two‐ to threefold higher in the susceptible cultivar; the relationship between root hair infection and inoculum density was also substantially stronger and more consistent in the susceptible cultivar. In the susceptible cultivar, the root hair infection rate peaked between 6 and 8 days after sowing and then declined. In the resistant cultivar, it increased over the 14‐day duration of each study. It appears that examination of root hair infection by microscopy in a bait crop of susceptible canola could serve as a useful tool for estimating P. brassicae inoculum levels in soil. In a separate trial, the relationship between inoculum density and clubroot severity, plant growth parameters, and seed yield was assessed under greenhouse conditions. Inoculum density in the susceptible genotype was strongly and positively correlated with clubroot severity and negatively correlated with plant height and seed yield. In addition, a single cropping cycle of the susceptible cultivar contributed significantly higher levels of resting spores to the soil in a greenhouse test than did a cycle of the resistant cultivar, as assessed by quantitative PCR and microscope analysis.
Computational analysis of storage synthesis in developing Brassica napus L. (oilseed rape) embryos: flux variability analysis in relation to 13C metabolic flux analysis
Authors: Hay Jordan , Schwender Jörg 
Published: April 2011

SummaryPlant oils are an important renewable resource, and seed oil content is a key agronomical trait that is in part controlled by the metabolic processes within developing seeds. A large‐scale model of cellular metabolism in developing embryos of Brassica napus (bna572) was used to predict biomass formation and to analyze metabolic steady states by flux variability analysis under different physiological conditions. Predicted flux patterns are highly correlated with results from prior 13C metabolic flux analysis of B. napus developing embryos. Minor differences from the experimental results arose because bna572 always selected only one sugar and one nitrogen source from the available alternatives, and failed to predict the use of the oxidative pentose phosphate pathway. Flux variability, indicative of alternative optimal solutions, revealed alternative pathways that can provide pyruvate and NADPH to plastidic fatty acid synthesis. The nutritional values of different medium substrates were compared based on the overall carbon conversion efficiency (CCE) for the biosynthesis of biomass. Although bna572 has a functional nitrogen assimilation pathway via glutamate synthase, the simulations predict an unexpected role of glycine decarboxylase operating in the direction of NH4+ assimilation. Analysis of the light‐dependent improvement of carbon economy predicted two metabolic phases. At very low light levels small reductions in CO2 efflux can be attributed to enzymes of the tricarboxylic acid cycle (oxoglutarate dehydrogenase, isocitrate dehydrogenase) and glycine decarboxylase. At higher light levels relevant to the 13C flux studies, ribulose‐1,5‐bisphosphate carboxylase activity is predicted to account fully for the light‐dependent changes in carbon balance.