bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Freshwater and Marine Environmental Influences on Life‐Stage‐Specific Survival Rates of Snake River Spring–Summer Chinook Salmon and Steelhead
Authors: Haeseker Steven L. , McCann Jerry A. , Tuomikoski Jack , Chockley Brandon
Published: January 2012

Pacific salmon Oncorhynchus spp. from the Snake River basin experience a wide range of environmental conditions during their freshwater, estuarine, and marine residence, which in turn influence their survival rates at each life stage. In addition, researchers have found that juvenile out‐migration conditions can influence subsequent survival during estuarine and marine residence, a concept known as the hydrosystem‐related, delayed‐mortality hypothesis. In this analysis, we calculated seasonal, life‐stage‐specific survival rate estimates for Snake River spring–summer Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss and conducted multiple‐regression analyses to identify the freshwater and marine environmental factors associated with survival at each life stage. We also conducted correlation analyses to test the hydrosystem‐related, delayed‐mortality hypothesis. We found that the freshwater variables we examined (the percentage of river flow spilled over out‐migration dams and water transit time) were important for characterizing the variation in survival rates not only during freshwater out‐migration but also during estuarine and marine residence. Of the marine factors examined, we found that the Pacific Decadal Oscillation index was the most important variable for characterizing the variation in the marine and cumulative smolt‐to‐adult survival rates of both species. In support of the hydrosystem‐related, delayed‐mortality hypothesis, we found that freshwater and marine survival rates were correlated, indicating that a portion of the mortality expressed after leaving the hydrosystem is related to processes affected by downstream migration conditions. Our results indicate that improvements in life‐stage‐specific and smolt‐to‐adult survival may be achievable across a range of marine conditions through increasing spill percentages and reducing water transit times during juvenile salmon out‐migration.
Effects of Live Artemia Nauplii Supplementation for Different Periods on Survival and Growth of Juvenile Signal Crayfish Pacifastacus leniusculus in the First Six Months of Intensive Culture
Authors: González Álvaro , Celada Jesús D , Carral José M , Sáez-Royuela María , García Vanesa , González Rocío
Published: January 2012

The rearing of astacid crayfishes under controlled conditions requires the addition of live zooplankton to basal dry diets. To investigate the possibility of minimizing the labor and costs involved in providing live feed, a 180-d experiment that focused on reducing the brine shrimp Artemia spp. supply period was carried out with stage 2 signal crayfish Pacifastacus leniusculus. From the onset of exogenous feeding, juvenile crayfish were fed a dry diet (formulated for salmonids) that was supplemented with live Artemia nauplii. Five treatments were implemented, varying the time at which the Artemia supplement was withdrawn (at days 80, 100, 120, or 160, or no withdrawal). No significant differences in survival, growth, or cheliped loss were found among groups throughout the trial. Survival rates at the end of the experiment (180 d) ranged from 62.3% to 66.7%, final carapace length averaged 20.6 mm, and final weight averaged 2.29 g. The results presented here indicate that juvenile astacid crayfishes can be reared without live feed supplements after an initial period of 80 d; thereafter, it is feasible to administer only a dry diet.
Safety of Copper Sulfate to Channel Catfish Eggs
Authors: Straus David L , Mitchell Andrew J , Carter Ray R , McEntire Matthew E , Steeby James A
Published: January 2012

Copper sulfate (CuSO4) is used in the catfish industry to control saprolegniasis (caused by the watermolds Achlya spp. or Saprolegnia spp.) on eggs. This study was designed to establish the margin of safety of CuSO4 at 10, 30, and 50 mg/L when applied for three times the normal treatment duration to hatching troughs containing channel catfish Ictalurus punctatus eggs in 26°C, flow-through well water. The safety of CuSO4 was indicated by the percentage of fry that hatched from the eggs. Eggs were treated daily until the embryos reached the eyed stage. The least-squares means ± SE of hatch rates were 40.8 ± 9.1, 80.9 ± 6.4, 64.2 ± 8.6, and 80.3 ± 6.6% for the 0-, 10-, 30-, and 50-mg/L CuSO4 treatments, respectively. The hatch rate for the 0-mg/L CuSO4 treatment was significantly different from that of all other CuSO4 treatments. Treating channel catfish eggs with five times the recommended dose of 10-mg/L CuSO4 for three times the recommended duration did not adversely affect the hatch rates in this study. There appears to be an adequate margin of safety above the therapeutic dose of 10 mg/L for channel catfish eggs; therefore, CuSO4 should be considered a safe treatment to alleviate egg losses caused by saprolegniasis.
Schism and plurality in Algerian society: the struggle of identity in the sociology of ‘the other’
Authors: Semmouk Ali
Published: January 2012

The questions of identity and citizenship in Algeria are complicated as well as a potentially divisive and axes of self-identification run across different lines. Individuals and groups may have more than one alignment where one locus of affiliation may overlap with another – the Berber with the Islamic, for instance, or the Arab with the secular. Construction of identity is mirrored by a parallel process in the construction of ‘the other’, both of which are guided by framing processes that prejudice particular elements of distinction and identity over others. The Algerian civil war sparked by the intervention of the military to stop the 1992 elections in which the Islamic Salvation Front (FIS) was emerging victorious brought this issue to the forefront. Islamist organizations influenced by the exclusivist thought of Sayyid Qutḅ such as the Armed Islamic Group (GIA) in particular employed a framing process based on creed to define and either include or exclude Algerian Muslims on the basis of criteria typically by Islamist takfiri groups that foment social divisiveness rather than rapprochement or toleration of ‘the other’. This trend is extremely pernicious to both central government and a plural society based on multiplicity and diversity that admits multiple and different voices.
Post-Qadhafi Libya: interactive dynamics and the political future
Authors: Sawani Youssef Mohammad
Published: January 2012

Libya’s contemporary history has been dominated by the interplay of the perpetual dynamics of religion, tribalism, oil and ideology. After 42 years in power Qadhafi was killed at the hands of revolutionaries and the final chapter of his dictatorial reign was terminated. With direct and powerful support from NATO and some Arab governments the revolution, led by the National Transitional Council and military councils in many Libyan cities, was another reflection of the supremacy of the perpetual dynamics. The purpose of this article is to examine the interaction of these dynamics and how they are echoed in post-Qadhafi Libya. An assessment is made of the manifestations related to these dynamics by providing a sketch of existing social and political features. This will help determine the fundamentals that shape the foreseeable future of the country and predict the role of the various political forces interacting in the field. The article is a product of direct research, analysis, eye-witness accounts and interviews in Libya with important personages and representatives of powerful currents now currently competing on the scene and vying for influence in the determination of the future of the country after Qadhafi.
Effect of bandgap engineering on the performance and reliability of a high-k based nanoscale charge trap flash memory
Authors: Zhu Chenxin , Xu Zhongguang , Huo Zongliang , Zheng Zhiwei , Cui Yanxiang , Wang Yumei , Liu Jing , Li Fanghua , Liu Ming
Published: January 2012

This paper investigates the performance of a bandgap engineered charge trapping structure consisting of HfO2/Al2O3/HfO2 (HAH) multilayer in comparison with a structure with a single HfO2 trapping layer. The study on the role of the inserted Al2O3 layer in improving the performance and reliability shows that the enhancement in charge trapping capability from the interfaces makes a considerable contribution to the larger memory window (7.8 V for the HAH 5/2/5 nm device and 3 V for the single HfO2 layer device, both under 12 V, 0.1 s program condition). The modulation of trapped charge distribution is proved by investigating the effect of varying the inserted Al2O3 layer position on program/erase (P/E) speed and retention characteristics, which is a crucial factor in improving the performance and reliability. This study can provide a guide for future designs of charge trap flash memories.
Bifurcation theory of ac electric arcing
Authors: Christen Thomas , Peinke Emanuel
Published: January 2012

The performance of alternating current (ac) electric arcing devices is related to arc extinction or its re-ignition at zero crossings of the current (so-called ‘current zero’, CZ). Theoretical investigations thus usually focus on the transient behaviour of arcs near CZ, e.g. by solving the modelling differential equations in the vicinity of CZ. This paper proposes as an alternative approach to investigate global mathematical properties of the underlying periodically driven dynamic system describing the electric circuit containing the arcing device. For instance, the uniqueness of the trivial solution associated with the insulating state indicates the extinction of any arc. The existence of non-trivial attractors (typically a time-periodic state) points to a re-ignition of certain arcs. The performance regions of arcing devices, such as circuit breakers and arc torches, can thus be identified with the regions of absence and existence, respectively, of non-trivial attractors. Most important for applications, the boundary of a performance region in the model parameter space is then associated with the bifurcation of the non-trivial attractors. The concept is illustrated for simple black-box arc models, such as the Mayr and the Cassie model, by calculating for various cases the performance boundaries associated with the bifurcation of ac arcs.
Early warning of climate tipping points from critical slowing down: comparing methods to improve robustness
Authors: Lenton T. M. , Livina V. N. , Dakos V. , van Nes E. H. , Scheffer M.
Published: January 2012

We address whether robust early warning signals can, in principle, be provided before a climate tipping point is reached, focusing on methods that seek to detect critical slowing down as a precursor of bifurcation. As a test bed, six previously analysed datasets are reconsidered, three palaeoclimate records approaching abrupt transitions at the end of the last ice age and three models of varying complexity forced through a collapse of the Atlantic thermohaline circulation. Approaches based on examining the lag-1 autocorrelation function or on detrended fluctuation analysis are applied together and compared. The effects of aggregating the data, detrending method, sliding window length and filtering bandwidth are examined. Robust indicators of critical slowing down are found prior to the abrupt warming event at the end of the Younger Dryas, but the indicators are less clear prior to the Bølling-Allerød warming, or glacial termination in Antarctica. Early warnings of thermohaline circulation collapse can be masked by inter-annual variability driven by atmospheric dynamics. However, rapidly decaying modes can be successfully filtered out by using a long bandwidth or by aggregating data. The two methods have complementary strengths and weaknesses and we recommend applying them together to improve the robustness of early warnings.
Data-based stochastic subgrid-scale parametrization: an approach using cluster-weighted modelling
Authors: Kwasniok Frank
Published: January 2012

A new approach for data-based stochastic parametrization of unresolved scales and processes in numerical weather and climate prediction models is introduced. The subgrid-scale model is conditional on the state of the resolved scales, consisting of a collection of local models. A clustering algorithm in the space of the resolved variables is combined with statistical modelling of the impact of the unresolved variables. The clusters and the parameters of the associated subgrid models are estimated simultaneously from data. The method is implemented and explored in the framework of the Lorenz '96 model using discrete Markov processes as local statistical models. Performance of the cluster-weighted Markov chain scheme is investigated for long-term simulations as well as ensemble prediction. It clearly outperforms simple parametrization schemes and compares favourably with another recently proposed subgrid modelling scheme also based on conditional Markov chains.
What can phylogeographic breaks in the livebearer Poeciliopsis turrubarensis tell about fish community boundaries in western Costa Rica?
Authors: Larson A. D. , Scarborough P. L. , Sayre C. L. , Johnson J. B.
Published: January 2012

This study asks if the geographic boundary delineating two fish communities in western Costa Rica is congruent with a phylogeographic break in a single widespread fish species Poeciliopsis turrubarensis (Poeciliidae) that spans this area. Such congruence would suggest that a common historical event (e.g. geological or climatic) could be responsible for both patterns. It was found that there was a shared break across a region in central Costa Rica suggesting a common cause may be responsible for both the abrupt shift in fish community composition and the genetic break in P. turrubarensis.
Superoxide dismutase activity of Helicobacter pylori per se from 158 clinical isolates and the characteristics
Authors: Morishita Keiko , Takeuchi Hiroaki , Morimoto Norihito , Shimamura Tomoko , Kadota Yoshu , Tsuda Masayuki , Taniguchi Taketoshi , Ukeda Hiroyuki , Yamamoto Tetsuya , Sugiura Tetsuro
Published: January 2012

We investigated the correlation between the SOD activity of Helicobacter pylori (H. pylori) and gastroduodenal diseases and the characteristics of strains exposed to oxidative stress. Two sequenced strains, 26695 and J99, and clinical isolates from 156 Japanese patients with gastroduodenal diseases such as gastric cancer (n= 59) and non‐cancer (n= 97) were used. SOD activities of all 158 isolates were measured and were divided into three groups: high‐SOD activity (>0.22, n= 2), moderate‐SOD activity (0.15≦≦0.22, n= 16) and low‐SOD activity (<0.15, n= 140). Expressions of H. pylori Fe‐SOD were examined by western blotting with anti‐H. pylori Fe‐SOD antibody prepared inhouse, and the profiles of Fe‐SOD activity were investigated by zymogram with activity staining in native‐PAGE. The characteristics of strains from high‐SOD and low‐SOD groups were examined under oxidative stress by paraquat. The average of H. pylori SOD activity was significantly higher in the cancer group than in the non‐cancer group (P < 0.05). However, irrespective of SOD activity level, the amount of Fe‐SOD expressed was variable among individual strains. Zymogram revealed a single band in moderate‐SOD and low‐SOD strains, but multiple bands in high‐SOD strains were observed. These bands were confirmed as H. pylori Fe‐SOD. Under oxidative stress with paraquat, low‐SOD strains were drastically eliminated without inducible SOD activity; however, high‐SOD strains were still viable with increased SOD activity. This study is the first to exhibit the characteristics of high‐SOD activity strains representing multiple bands in zymograms and the correlation between H. pylori SOD activity and gastric cancer.
No clinically significant valvular regurgitation in long‐term cabergoline treatment for prolactinoma
Authors: Halperin Irene , Aller Javier , Varela César , Mora Mireia , Abad Ainhoa , Doltra Ada , Santos Alicia Estrella , Batista Esther , García‐Pavía Pablo , Sitges Marta , Mirelis Jesús G. , Lucas Tomás , Puig‐Domingo Manel
Published: January 2012

Background

An association between treatment for Parkinson's disease with certain dopaminergic drugs and development of cardiac valve impairment has been reported. Recent studies in hyperprolactinaemic patients treated with cabergoline (CAB) have shown either no significant findings or mild tricuspid regurgitation.

Objective

To determine the prevalence of cardiac valve dysfunction in patients with hyperprolactinaemic conditions chronically treated with CAB or bromocriptine (BR).

Design

Retrospective, multicentric, cross‐sectional study of cases vs controls.

Patients

Eighty‐three hyperprolactinaemic patients (15 men, 68 women aged 16·7–63 years; 64% microprolactinomas, 28% macroprolactinomas and 8% other etiologies) from three Spanish university hospitals chronically treated with BR (14–562·5 weeks, cumulative dose 5603 ± 7729 mg) or CAB (12–765 weeks, 217·4 ± 306·6 mg).

Measurements

Transthoracic echocardiographic assessment of valvular regurgitation and thickening, mitral valve tenting area and left‐ventricular ejection fraction from 83 patients were compared with results from 58 age‐ and sex‐matched controls and correlated with cumulative doses of dopaminergic drugs.

Results

No significant differences in valvular regurgitation, valve thickness or any other echocardiographic parameter were observed between controls and patients, except for 15 patients in the higher quartile of CAB cumulative dose (>180 mg), with increased prevalence of mild tricuspid regurgitation (6/15, 40% vs 8/58, 13·8%, P = 0·024; OR 4·1; 1·1–14·9). High BR cumulative dose was associated with no significant findings.

Conclusions

No increased valvular involvement was found after long‐term dopaminergic therapy for hyperprolactinaemia except for a significant increase in mild tricuspid regurgitation associated with high cumulative doses of CAB; BR seems spared from this adverse effect, although the low number of cases limits this analysis. Cumulative dose registry and long‐term studies are warranted to definitely clarify this item.
Prolactinomas in men: a multicentre and retrospective analysis of treatment outcome
Authors: Iglesias Pedro , Bernal Carmen , Villabona Carles , Castro José C. , Arrieta Francisco , Díez Juan J.
Published: January 2012

Aims

To assess treatment outcome in male patients with micro‐ and macroprolactinomas.

Design

Multicentre and retrospective study.

Patients

Eighty‐eight male patients (15 micro‐ and 73 macroprolactinomas), aged 40·3 ± 14·7 years, were studied. Time of follow‐up ranged from 3 to 244 months.

Methods

Clinical, hormonal and radiological data were registered at diagnosis and follow‐up. Treatment outcome was evaluated in relation to the modality of therapy (dopamine agonists, surgery and radiation therapy).

Results

Dopamine agonists normalized prolactin levels in 73·3% and 65·2% of patients with micro‐ and macroprolactinomas, respectively. Disappearance of tumour was reached in 53·3% and 28·3% of subjects with micro‐ and macroprolactinomas, respectively. Tumour absence at last visit was achieved in 7 of 14 patients with macroprolactinoma and treated by means of dual therapy (dopamine agonists and neurosurgery) and in 9 of 13 patients with macroprolactinoma managed with triple therapy (dopamine agonists, neurosurgery and radiation therapy). Normalization of prolactin levels at last visit was present in 68·9%, 79·6% and 69·2% of patients treated by medical therapy, dual therapy and triple therapy, respectively (differences not significant). Multivariate logistic regression analysis showed that the time on therapy was the only significant variable related to tumour disappearance.

Conclusion

We conclude that medical therapy normalizes prolactin and reduces tumour size in the majority of men with prolactinomas. The addition of pituitary surgery with or without radiation therapy does not offer significant advantages over medical therapy with dopamine agonists in male patients with macroprolactinomas.
A randomized, double‐blind, crossover study comparing two‐ and four‐dose hydrocortisone regimen with regard to quality of life, cortisol and ACTH profiles in patients with primary adrenal insufficiency
Authors: Ekman Bertil , Bachrach‐Lindström Margareta , Lindström Torbjörn , Wahlberg Jeanette , Blomgren Johan , Arnqvist Hans J.
Published: January 2012

Context

Current guidelines on how to divide the daily cortisol substitution dose in patients with primary adrenal insufficiency (PAI) are controversial and mainly based on empirical data.

Objective

To assess how an equal dose of hydrocortisone (HC) given either four times daily or twice daily influence diurnal profiles of cortisol and ACTH, patient preferences and health‐related quality of life (HRQoL).

Design

Double blind, crossover.

Methods

Fifteen patients with PAI (six women) were included. Capsules of HC or placebo were given at 07:00, 12:00, 16:00 and 22:00 h in 4‐week treatment periods: either one period with four doses (10 + 10 + 5 + 5 mg) or one period with two doses (20 + 0 + 10 + 0 mg). Diurnal profiles of cortisol and ACTH were collected, and area under the curve (AUC) was calculated. Questionnaires were used to evaluate patient preferences and HRQoL.

Results

The four‐dose regimen gave a higher serum cortisol before tablet intake in the morning (P = 0·027) and a higher 24‐h cortisolAUC (P < 0·0001) compared with the two‐dose period. In contrast, a lower median plasma ACTH in the morning before tablet intake (P = 0·003) and a lower 24‐h ln(ACTHAUC) were found during the four‐dose period. The patients preferred the four‐dose regimen (P = 0·03), and the HRQoL scores tended to be higher (high score indicates better HRQoL) for the four‐dose period. In summary, a four‐dose regimen gives increased availability of cortisol and an enhanced effect with a less elevated ACTH in the morning in comparison with a two‐dose regimen but the effect on HRQoL remains inconclusive.
Prevalence and progression of basal ganglia calcification and its pathogenic mechanism in patients with idiopathic hypoparathyroidism
Authors: Goswami Ravinder , Sharma Raju , Sreenivas Vishnubhatla , Gupta Nandita , Ganapathy Arthi , Das Sathi
Published: January 2012

Background

The pathogenesis of basal ganglia calcification (BGC) in hypoparathyroidism is not clear. Its occurrence in hypocalcaemic milieu of hypoparathyroidism is believed to be due to high serum calcium–phosphorus product and poor calcium control.

Objective

To report details of BGC in patients with idiopathic hypoparathyroidism (IH) and factors determining its progression during follow‐up.

Method

Clinical, biochemical characteristics and a meningioma‐expressed antigen‐6 (MGEA6) gene polymorphism were analysed in 145 patients with IH, recruited since 1998, to determine the factors associated with BGC. The progression of BGC and its relationship with metabolic control of serum calcium, phosphorus, serum 25(OH)D and 1,25(OH)2D were assessed after a mean of 6·9 ± 3·5 years in 49 of them.

Results

Basal ganglia calcification was present in 73·8% (95% CI: 66·6%–81·0%) of subjects affecting the globus pallidus (68·8%) putamen (55·9%) and caudate nucleus (54·8%). The other sites calcified were grey–white junction (39·8%), cerebellar parenchyma (31·2%), thalamus (29·0%) and dentate nuclei (24·7%). Parkinsonism and dystonic symptoms were present in three cases. The presence of BGC at presentation was associated with calcification of the choroid plexus, cataract and an increased risk of seizures but not tetany. The progression of BGC during follow‐up was related to calcium/phosphorus ratio. For every 1% increase in this ratio, the odds of progression decreased by 5% (OR: 0·95, 95% CI: 0·93–0·99, P < 0·001). A MGEA6 polymorphism, serum 25(OH)D and 1,25(OH)2D did not affect progression of BGC.

Conclusion

Basal ganglia calcification occurs in 73·8% of patients with IH and correlates with the duration of hypocalcaemia, choroid plexus calcification, seizures and cataract. The progression of BGC is related to the calcium/phosphorus ratio during follow‐up. This brings forth the importance of adequate phosphorus control in the management of hypoparathyroidism.
Dietary habits and their relationship with hormones and metabolism in overweight and obese women with polycystic ovary syndrome
Authors: Altieri Paola , Cavazza Carla , Pasqui Francesca , Morselli Antonio M. , Gambineri Alessandra , Pasquali Renato
Published: January 2012

Objective

This study investigates energy intake, macronutrient composition and habitual food choices in overweight/obese women with polycystic ovary syndrome (PCOS) and controls similar for age and body mass index (BMI), and their relationship with hormonal and metabolic parameters.

Design

Case–control study carried out in an academic hospital in Bologna, Italy.

Patients

One‐hundred obese or overweight (BMI >25 kg/m2) women with PCOS, diagnosed according to Rotterdam criteria, and 100 age‐ and BMI‐matched controls.

Measurements

Dietary habits were investigated by means of the 7 days food diary. Fasting hormones and metabolic parameters were investigated in all subjects.

Results

We showed that diet does not differ between the two groups as regards energy, macronutrient and advanced glycosylated end product intake, except for a lower percentage of energy from lipids and a higher intake of fibres by PCOS women. PCOS women were characterized by a higher consumption of cheese and high‐glycaemic index starchy sweets and a preference for raw oil rather than other cooked fats, compared to controls. The PCOS or control status influenced some of the relationships between dietary components, food choices and metabolic parameters, particularly insulinAUC and HDL‐cholesterol.

Conclusions

This study did not find major differences in dietary habits between PCOS and normoandrogenic control women. Our findings support the hypothesis that specific foods may influence metabolic and hormonal pattern and that this relationship may be differently regulated in PCOS and normoandrogenic women; however, they give little support to the hypothesis of a strong dependence of PCOS status on nutritional factors.
A small RNA that regulates motility and biofilm formation in response to changes in nutrient availability in Escherichia coli
Authors: Thomason Maureen K. , Fontaine Fanette , De Lay Nicholas , Storz Gisela
Published: January 2012

In bacteria, many small regulatory RNAs (sRNAs) are induced in response to specific environmental signals or stresses and act by base‐pairing with mRNA targets to affect protein translation or mRNA stability. In Escherichia coli, the gene for the sRNA IS061/IsrA, here renamed McaS, was predicted to reside in an intergenic region between abgR, encoding a transcription regulator and ydaL, encoding a small MutS‐related protein. We show that McaS is a ∼ 95 nt transcript whose expression increases over growth, peaking in early‐to‐mid stationary phase, or when glucose is limiting. McaS uses three discrete single‐stranded regions to regulate mRNA targets involved in various aspects of biofilm formation. McaS represses csgD, the transcription regulator of curli biogenesis and activates flhD, the master transcription regulator of flagella synthesis leading to increased motility, a process not previously reported to be regulated by sRNAs. McaS also regulates pgaA, a porin required for the export of the polysaccharide poly β‐1,6‐N‐acetyl‐d‐glucosamine. Consequently, high levels of McaS result in increased biofilm formation while a strain lacking mcaS shows reduced biofilm formation. Based on our observations, we propose that, in response to limited nutrient availability, increasing levels of McaS modulate steps in the progression to a sessile lifestyle.
SpyA is a membrane‐bound ADP‐ribosyltransferase of Streptococcus pyogenes which modifies a streptococcal peptide, SpyB
Authors: Korotkova Natalia , Hoff Jessica S. , Becker Devon M. , Quinn John Kyle Heggen , Icenogle Laura M. , Moseley Steve L.
Published: January 2012

All sequenced genomes of Streptococcus pyogenes (Group A Streptococcus, GAS) encode a protein, SpyA, with homology to C3‐like ADP‐ribosyltransferase toxins. SpyA is a novel virulence factor which plays a role in pathogenesis in a mouse model of soft‐tissue infection. In this study we demonstrate that SpyA is a surface‐exposed membrane protein which is anchored to the streptococcal membrane by an N‐terminal transmembrane sequence. We identified a small gene upstream of spyA, designated spyB, which encodes a peptide of 35 amino acids, and is co‐transcribed with spyA. Expression of spyBA is strongly influenced by translational coupling: mutational inactivation of spyB translation completely abolishes translation of spyA. spyB expression increases with increasing cell density and reaches its maximum at late exponential growth phase. The SpyB N‐terminus is predicted to fold into an amphipathic α‐helix, a structural motif that targets a protein to the cytoplasmic membrane. Consistent with the prediction, we found that a SpyB fusion with peptide affinity tags is located in the streptococcal membrane. An ADP‐ribosylation assay with recombinant SpyA demonstrated that SpyA modifies SpyB. Thus, our study suggests that ADP‐ribosylation of SpyB may be an important function of SpyA.
Randomized pharmacodynamic and pharmacogenetic trial of dronabinol effects on colon transit in irritable bowel syndrome‐diarrhea
Authors: Wong B. S. , Camilleri M. , Eckert D. , Carlson P. , Ryks M. , Burton D. , Zinsmeister A. R.
Published: January 2012

Background  Genetic variation in endocannabinoid metabolism is associated with colonic transit in irritable bowel syndrome (IBS) with diarrhea (IBS‐D). The nonselective cannabinoid (CB) receptor agonist, dronabinol (DRO), reduced fasting colonic motility in nonconstipated IBS. FAAH and CNR1 variants influenced DRO’s effects on colonic motility. Our aims were: (i) to compare dose‐related effects of DRO to placebo (PLA) on gut transit in IBS‐D, and (ii) to examine influence of genetic variations in CB mechanisms on DRO’s transit effects.

Methods  Thirty‐six IBS‐D volunteers were randomized (double‐blind, concealed allocation) to twice per day PLA (n = 13), DRO 2.5 mg (n = 10), or DRO 5 mg (n = 13) for 2 days. We assessed gastric, small bowel, and colonic transit by validated radioscintigraphy and genotyped the single nucleotide polymorphisms CNR1 rs806378 and FAAH rs324420. Data analysis utilized a dominant genetic model.

Key Results  Overall treatment effects of DRO on gastric, small bowel, or colonic transit were not detected. CNR1 rs806378 CT/TT was associated with a modest delay in colonic transit at 24 h compared with CC (P = 0.13 for differential treatment effects on postminus pretreatment changes in colonic transit by genotype). No significant interaction of treatment with FAAH rs324420 was detected.

Conclusions & Inferences  Overall, DRO 2.5 or 5 mg twice per day for 2 days had no effect on gut transit in IBS‐D. There appears to be a treatment‐by‐genotype effect, whereby DRO preferentially delays colonic transit in those with the CNR1 rs806378 CT/TT genotypes. Further study of CB pharmacogenetics may help identify a subset of IBS‐D patients most likely to benefit from CB agonist therapy.
A risk score for early cytomegalovirus reactivation after allogeneic stem cell transplantation identifies low‐, intermediate‐, and high‐risk groups: reactivation risk is increased by graft‐versus‐host disease only in the intermediate‐risk group
Authors: George B. , Kerridge I.H. , Gilroy N. , Huang G. , Hertzberg M.S. , Bradstock K.F. , Gottlieb D.J.
Published: January 2012

Background

This retrospective study was aimed at establishing a clinical score to stratify the risk of cytomegalovirus (CMV) reactivation in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) in order to direct strategies for post‐transplant CMV monitoring and therapy.

Patients and methods

In total, 335 adult patients undergoing HSCT were analyzed and divided into a training set (n = 235) and a validation set (n = 100). Logistic regression analysis on the training set identified recipient and donor CMV seropositivity, acute graft‐versus‐host disease (GVHD), and use of anti‐thymocyte globulin or alemtuzumab as significant risk factors for CMV reactivation. Weighted scores were assigned to each factor. A weighted score (CMV scoring index [CSI]) was calculated for each patient using the scores of all risk factors except for GVHD. The index was collapsed into 3 risk groups – low risk (score of 0–2), intermediate risk (score of 3–5), and high risk (score of 6–7) – and reactivation rates were calculated. In the training set, CMV reactivation occurred in 5.8% in the low‐risk group, 44.8% in the intermediate‐risk group, and 67.7% in the high‐risk group.

Results

In patients with an intermediate CSI only, significantly higher reactivation rates were seen in the presence of corticosteroid treatment for GVHD (57.8% vs. 24.5%, P < 0.01). These findings were similar in the validation set with reactivation rates of 0% in the low‐risk, 46% in the intermediate‐risk, and 68.4% in the high‐risk groups. As seen in the training set, the presence of GVHD was associated with higher CMV reactivation rates only in the intermediate‐risk group (64% vs. 28% in the absence of GVHD, P = 0.02).

Conclusions

Identification of these 3 risk groups in association with the presence or absence of GVHD will help transplant units to make pre‐transplant policy decisions about prophylactic, pre‐emptive, or experimental CMV prevention strategies in groups of patients undergoing HSCT, as well as in those developing GVHD post transplant.
Chryseobacterium indologenes subcutaneous port‐related bacteremia in a liver transplant patient
Authors: Shah S. , Sarwar U. , King E.A. , Lat A.
Published: January 2012

Chryseobacterium indologenes is a rare cause of infection in select immunosuppressed hosts. Most prior reports are from Taiwan, in patients with diabetes mellitus or malignancies. Infections caused by C. indologenes are generally associated with indwelling devices, and the organism may be resistant to many commonly utilized broad‐spectrum antibiotics. We report the first case, to our knowledge, of C. indologenes subcutaneous port‐related bacteremia in a liver transplant recipient. The isolates were resistant to antibiotics previously reported as active, and device removal was required for treatment success.
Leaf patch clamp pressure probe measurements on olive leaves in a nearly turgorless state
Authors: Ehrenberger W. , Rüger S. , Rodríguez‐Domínguez C. M. , Díaz‐Espejo A. , Fernández J.E. , Moreno J. , Zimmermann D. , Sukhorukov V. L. , Zimmermann U.
Published: January 2012

The non‐invasive leaf patch clamp pressure (LPCP) probe measures the attenuated pressure of a leaf patch, Pp, in response to an externally applied magnetic force. Pp is inversely coupled with leaf turgor pressure, Pc, i.e. at high Pc values the Pp values are small and at low Pc values the Pp values are high. This relationship between Pc and Pp could also be verified for 2‐m tall olive trees under laboratory conditions using the cell turgor pressure probe. When the laboratory plants were subjected to severe water stress (Pc dropped below ca. 50 kPa), Pp curves show reverse diurnal changes, i.e. during the light regime (high transpiration) a minimum Pp value, and during darkness a peak Pp value is recorded. This reversal of the Pp curves was completely reversible. Upon watering, the original diurnal Pp changes were re‐established within 2–3 days. Olive trees in the field showed a similar turnover of the shape of the Pp curves upon drought, despite pronounced fluctuations in microclimate. The reversal of the Pp curves is most likely due to accumulation of air in the leaves. This assumption was supported with cross‐sections through leaves subjected to prolonged drought. In contrast to well‐watered leaves, microscopic inspection of leaves exhibiting inverse diurnal Pp curves revealed large air‐filled areas in parenchyma tissue. Significantly larger amounts of air could also be extracted from water‐stressed leaves than from well‐watered leaves using the cell turgor pressure probe. Furthermore, theoretical analysis of the experimental Pp curves shows that the propagation of pressure through the nearly turgorless leaf must be exclusively dictated by air. Equations are derived that provide valuable information about the water status of olive leaves close to zero Pc.
Role of psychological empowerment in the reduction of burnout in Canadian healthcare workers
Authors: Boudrias Jean‐Sébastien , Morin Alexandre J. S. , Brodeur Marie‐Michèle
Published: January 2012

In this study, we investigated the role of psychological empowerment as a protective factor for burnout among workers exposed to work‐related stressors (e.g. daily hassles, overload, job changes). A cross‐sectional questionnaire study was conducted, with a convenience sample of 401 healthcare workers. Hierarchical multiple regressions were performed to test main and moderating effects of empowerment cognitions. Results revealed partial support for the hypotheses. Only the job meaningfulness cognition exerts a beneficent main effect on all burnout symptoms beyond the effect of stressors. Some moderating effects differing according to burnout dimensions were also found. Most interestingly, high levels of empowerment cognitions accentuate the effect of change‐related resources in the reduction of emotional exhaustion. Because psychological empowerment has beneficial effects, organizations could rely on different strategies to enhance it.
Qualitative observation in a clinical setting: Challenges at end of life
Authors: Bloomer Melissa J. , Cross Wendy , Endacott Ruth , O'Connor Margaret , Moss Cheryle
Published: January 2012

This paper explores the methodological challenges associated with undertaking qualitative observation in the clinical setting at end of life. The authors reflect on their experiences of using non‐participant observation to explore the nursing care delivered to dying patients in acute hospital wards. The challenges of observation as a method, clearly defining the participant group and involving vulnerable populations, such as the dying patients and their families, will be discussed. Consideration is also given to defining and working within the observational field, the researchers' dual roles, cost versus benefit, impact of culture, religion and ethnicity, and the determination of research limits/boundaries, with reflections from the authors' own experiences used to exemplify the issues.
Polymorphism of spermatozoa in Largus rufipennis Laporte 1832 (Heteroptera: Pyrrhocoroidea: Largidae)
Authors: Araújo Vinícius Albano , Báo Sônia Nair , Lino‐Neto José
Published: January 2012

The production of polymorphic spermatozoa has been registered in various insect orders such as Diptera, Lepidoptera, and Hemiptera. In this work, morphology of two types of spermatozoa produced by Largus rufipennis was reported for the first time in the Largidae family. For this, techniques including optical and transmission electron microscopy were used. Spermatozoa measured, on the average, 260 and 200 μm, and both types possessed a nucleus measuring on the average 65 μm. No ultrastructural differences were observed between the two spermatozoa types from L. rufipennis. The head region is composed of an acrosome, a nucleus, and part of the centriolar adjunct. The centriolar adjunct is in parallel with the nucleus and followed by mitochondrial derivates. The flagellum consists of an axoneme (9 + 9 + 2 microtubules) and two mitochondrial derivatives; no other accessory bodies were observed. The mitochondrial derivatives are symmetric in size and diameter. A similar quantity of the two spermatozoa types was observed in the seminal vesicle (57% of the large type and 43% of the small type), while in the spermatheca of the female, the larger spermatozoa were preferentially stored (87%). These results permit discussions concerning of the species biology reproduction, most specifically sperm competition strategies.
The Role of Fair Value Accounting in Promoting Government Accountability
Authors: Rodríguez Bolívar Manuel Pedro , Navarro Galera Andrés
Published: January 2012

A key factor to improve the financial accountability of governments is the existence of a set of generally accepted financial reporting of standards, such as IPSAS issued by the IFAC, which seek to enhance information transparency. This paper examines the capability of fair value accounting to improve, through financial transparency, government accountability, analysing the possible effect of the implementation of this measurement basis on understandability, comparability and timeliness—three qualitative characteristics linked to the relevance of financial reporting. This paper further considers whether the difficulties involved in achieving FV estimations could affect government financial accountability. The findings indicate that FVA implementation could enhance accountability by improving understandability, comparability and timeliness in governmental financial reporting, although the use of objective measures to estimate the FV of assets is fundamental. In addition, the type of assets and the existence of an active market are crucial to improving the comparability of financial statements under FVA, whereas improving timeliness could be limited by the possibility of estimating FV measures in‐house.
Does the Stock Market Gender Stereotype Corporate Boards? Evidence from the Market's Reaction to Directors' Trades
Authors: Gregory Alan , Jeanes Emma , Tharyan Rajesh , Tonks Ian
Published: January 2012

Attitudes towards male and female managers within organizations are well documented, but how the stock market perceives their relative capabilities is less studied. Recent evidence documents a negative short‐run market reaction to the appointment of female chief executive officers and suggests that female executives are less informed than their male counterparts about future corporate performance. These results appear to dispute the stock market value of having women on corporate boards. However, such short‐run market reactions may retain a ‘gender bias’, reflecting the prevalence of negative stereotypes, where the market reacts to ‘beliefs’ rather than ‘performance’. This study tests for such bias by examining the stock market reaction to directors' trades in their own companies' shares, by measuring both the short‐run and longer‐term returns after the directors' trades. Allowing for firm and trade effects, some evidence is found that, in the longer term, markets recognize that female executives' trades are informative about future corporate performance, although initially markets underestimate these effects. This has important implications for research that has attempted to assess the value of board diversity by examining only short‐run stock market responses.
PRESENTISM, TRUTH AND SUPERVENIENCE
Authors: Baron Sam
Published: January 2012

Truthmaker theory is commonly thought to pose a challenge for presentism. Presentism seems to lack the ontological and ideological resources required to adequately underwrite the truth of propositions concerning the past. That is because if presentism is true, then the past does not exist. According to the standard response to this challenge, the truth of propositions concerning the past supervenes on surrogate entities that ‘stand proxy’ for past things. I argue that in order for the standard response to the truthmaker challenge to succeed these surrogate entities must stand in necessary connections to the past. I go on to argue that because the standard response is already committed to denying the existence of cross‐temporal modal connections of this kind, by its own lights that response is in error.1
Generalized Additive Models for Location, Scale and Shape for High Dimensional Data—A Flexible Approach Based on Boosting
Authors: Mayr Andreas , Fenske Nora , Hofner Benjamin , Kneib Thomas , Schmid Matthias
Published: January 2012

Generalized additive models for location, scale and shape (GAMLSSs) are a popular semiparametric modelling approach that, in contrast with conventional generalized additive models, regress not only the expected mean but also every distribution parameter (e.g. location, scale and shape) to a set of covariates. Current fitting procedures for GAMLSSs are infeasible for high dimensional data set-ups and require variable selection based on (potentially problematic) information criteria. The present work describes a boosting algorithm for high dimensional GAMLSSs that was developed to overcome these limitations. Specifically, the new algorithm was designed to allow the simultaneous estimation of predictor effects and variable selection. The algorithm proposed was applied to Munich rental guide data, which are used by landlords and tenants as a reference for the average rent of a flat depending on its characteristics and spatial features. The net rent predictions that resulted from the high dimensional GAMLSSs were found to be highly competitive and covariate-specific prediction intervals showed a major improvement over classical generalized additive models.
From Sheriff's Deputies to Immigration Officers: Screening Immigrant Status in a Tennessee Jail
Authors: ARMENTA AMADA
Published: January 2012

This article contributes to emerging literature documenting the devolution of immigration enforcement authority by focusing on the implementation of the 287(g) program in Davidson County, Tennessee. It outlines how deputized immigration officers do their work as well as the ways they come to think about their roles in the larger immigration bureaucracy. Immigration officers see themselves as objective administrators whose primary responsibilities are to identify and process immigrants for removal, but who are not responsible for their subsequent deportation. While immigration officers never waiver about their obligation to uphold the rule of law, alternate narratives emerge depending on how they feel about the immigrants they encounter. These frames range from pride at identifying “criminal aliens” to guilt for processing immigrants who had been arrested for very minor violations. Ultimately, this work shows deputized immigration officers act as extensions of the federal government rather than as independent agents.
Nigral iron deposition occurs across motor phenotypes of Parkinson’s disease
Authors: Jin L. , Wang J. , Jin H. , Fei G. , Zhang Y. , Chen W. , Zhao L. , Zhao N. , Sun X. , Zeng M. , Zhong C.
Published: January 2012

Background and purpose:  To investigate whether brain iron deposition correlates with motor phenotypic expressions of Parkinson’s disease.

Methods:  We subtyped patients with Parkinson’s disease according to their main motor symptoms (tremor, rigidity/bradykinesia) into three subgroups: tremor‐dominant subgroup, akinetic/rigid‐dominant subgroup, or mixed subgroup. The iron levels in bilateral substantia nigra, globus pallidus, putamen, the head of caudate, and red nucleus of 87 patients and 50 control subjects were assayed by measuring phase values using susceptibility‐weighted phase imaging in a 3‐tesla magnetic resonance system. The serum ceruloplasmin levels of all subjects were determined.

Results:  The bilateral average phase values of the substantia nigra and all other brain regions examined did not correlate with the main motor symptoms of Parkinson’s disease in the total patient group or when patients were grouped according to serum ceruloplasmin levels. Significant correlations between serum ceruloplasmin levels and nigral bilateral average phase values were observed in the tremor and akinetic/rigid‐dominant subgroups. Analysis of patients without prior dopaminergic medication exhibited similar results. Increased nigral iron content correlated with disease severity as assayed by the Unified Parkinson’s Disease Rating Scale motor scores in the PDAR subgroup.

Conclusions:  These findings suggest that nigral iron deposition, correlating with decreased serum ceruloplasmin levels, is a risk factor in Parkinson’s disease across multiple motor phenotypic expressions.