bluuebunny/crossref_metadata_2025 huggingface dataset:
Better off alone! Reproductive competition and ecological constraints determine sociality in the African striped mouse (Rhabdomys pumilio)
Authors: Schoepf Ivana , Schradin Carsten
Published: January 2012

1. While the reasons for group‐living have been studied for decades, little is known about why individuals become solitary.

2. Several previous experimental studies could demonstrate that group‐living can arises as a consequence of ecological constraints.

3. It has been argued that reproductive competition between group members leads to significant costs of group‐living, being a main reason of solitary‐living. However, so far, no studies tested experimentally whether reproductive competition can explain solitary‐living.

4. Using a socially flexible species, the African striped mouse (Rhabdomys pumilio), we tested experimentally in the field whether dispersal and solitary‐living are more likely to occur when reproductive competition is present.

5. We investigated ecological constraints, here expressed as a function of population density, by removing groups of striped mice and creating vacant territories. To control for the effect of reproductive competition, which occurs only during the breeding season, we performed experiments during both the breeding and the non‐breeding season. This is the first removal experiment performed in a species with communal breeding during the non‐breeding season.

6. During the breeding season, when population density was low, more striped mice from experimental groups moved into the vacant territories and became solitary than striped mice from control groups. This is in support of the ecological constraints hypothesis.

7. During the non‐breeding season, striped mice remained group‐living despite the availability of free territories. Significantly, more striped mice became solitary‐living during the breeding than during the non‐breeding season. This is the first experimental support for the reproductive competition hypothesis explaining solitary‐living.

8. Analysis of the sexual maturity of males showed that males which became solitary had a higher reproductive potential than males that remained group‐living. Analysis of the body mass data of females showed that more solitary females reproduced than group‐living females. These results indicate that by becoming solitary individuals of both sexes avoided costs of reproductive competition within groups.

9. Our study provides experimental evidence that reproductive competition within groups can lead to dispersal and solitary‐living.
The impact of collaborative and individualized student response system strategies on learner motivation, metacognition, and knowledge transfer
Authors: Jones M.E. , Antonenko P.D. , Greenwood C.M.
Published: January 2012

This study investigated the impact of collaborative and individualized student response system‐based instruction on learner motivation, metacognition, and concept transfer in a large‐enrolment undergraduate science course. Participants in the collaborative group responded to conceptual questions, discussed their responses in small groups, and provided a revised response to the question (peer instruction [PI]). A comparison group provided individualized responses (IRs) to the same questions. Results of the motivation measure revealed a drop in confidence for students in both groups. This may be explained by a significant increase in the knowledge of cognition in both IR and PI groups, which likely mediated a recalibration of confidence to a lower, yet more realistic level. A significant interaction was found between gender and student response system strategy relative to the regulation of cognition, revealing that females improved in the PI group, while males reported improvement in the regulation of cognition in the IR group. A custom instrument was developed to measure near and far concept transfer abilities. The PI group scored significantly higher on the test of near transfer than the IR group.
Multiple mechanisms for trait effects on litter decomposition: moving beyond home‐field advantage with a new hypothesis
Authors: Freschet Grégoire T. , Aerts Rien , Cornelissen Johannes H. C.
Published: January 2012

1. Evidence is growing that leaf litter generally decomposes faster than expected in its environment of origin, owing to specialization of litter and topsoil decomposer communities to break down litter encountered most often. Nevertheless, this home‐field advantage (HFA) in decomposition is inconsistently supported by experimental data and fails to account for situations where contrasting qualities of litter coexist within the same litter matrix.

2. In contrast to the HFA hypothesis, which expects a positive interaction between every litter species produced locally and the local decomposer communities irrespective of litter species quality, we define here an alternative substrate quality–matrix quality interaction (SMI) hypothesis that expects a continuum from positive to negative interaction between specific litters (substrates) and decomposer communities as specific litters and the ecosystem litter layer (i.e. the matrix, which drives local decomposer community composition) become increasingly dissimilar in quality.

3. To test this hypothesis, we conducted a reciprocal transplant decomposition experiment of eight leaf, six fine‐stem and nine fine‐root litter species from three neighbouring ecosystems of the subarctic biome: dry forest, riparian forest and forest‐surrounded pond; and characterized the quality (represented by lignin content and an integrated measure of carbon/nutrient economics) of each litter species and each ecosystem litter layer.

4. We found substantial overall effects of SMI on decomposition rates of leaf (20% explained variance), stem (14%) and root (15%) litters, although this effect was lower than the single effects of litter quality and microclimate (remaining explained variance). Despite being partly inconsistent across litter species, likely due to the complexity of litter quality–decomposer community relationships, the SMI hypothesis appeared more broadly applicable than the HFA hypothesis.

5.Synthesis. We demonstrate here that plant traits, likely via their control on litter and topsoil decomposer community composition, have indirect effects on litter breakdown rates, not only at the interface between ecosystems but alsowithinecosystems, with likely implications for many other ecosystems world‐wide. These results suggest functional variation in decomposer communities between ecosystems with respect to theirefficiencyto degrade litters with contrasting qualities, such as different lignolytic and detoxification activities but also contrasting efficiencies to degrade non‐recalcitrant tissues.
Inferring community assembly mechanisms from functional diversity patterns: the importance of multiple assembly processes
Authors: Spasojevic Marko J. , Suding Katharine N.
Published: January 2012

1. Many studies of community assembly focus on two mechanisms: environmental filtering and competitive interactions. This focus ignores the importance of other assembly processes such as equalizing fitness processes and facilitation. The contribution of different processes to community assembly can be elucidated by examining functional diversity patterns of traits that differ in their contribution to different assembly processes.

2. In alpine tundra, we explored trait patterns along a stress–resource gradient that varied in productivity, nitrogen availability and soil moisture. We explore whether functional diversity is low in abiotic stressful environments and increases in more benign environments as competition becomes more important, and if equalizing fitness processes and facilitation affect functional diversity. We calculated community‐weighted mean trait values and functional diversity for specific leaf area (SLA), leaf area, stomatal conductance, plant height and chlorophyll content as well as multivariate functional diversity and phylogenetic diversity.

3. At the community level, functional diversity increased at both ends of the gradient: high resource availability was associated with greater functional diversity in height and leaf area, and lower resource availability was associated with greater functional diversity in SLA, stomatal conductance, and chlorophyll content. As a result of this trade‐off in functional diversity among traits, multivariate functional diversity did not change across the gradient. Phylogenetic diversity increased with increasing resource availability.

4. We find evidence for at least three assembly processes along the gradient. Abiotic filtering by wind and cold exposure may reduce functional diversity in height and leaf area at the low resource end of the gradient. Also at low resource availability, increasing functional diversity in the other three traits suggests competition for below‐ground resources. At the resource‐rich end of the gradient, increased functional diversity in height and leaf area suggests increased competition for light or facilitation.

5.
Synthesis: Our results suggest that multiple assembly processes (abiotic filtering, above‐ground competition, and below‐ground competition) operate simultaneously to structure plant communities along a stress–resource gradient. These processes would be obscured by a single multivariate trait index or phylogenetic diversity and are only evident by analysing functional diversity patterns of individual traits.
Speciation in the Rana chensinensis species complex and its relationship to the uplift of the Qinghai–Tibetan Plateau
Authors: ZHOU WEI‐WEI , WEN YANG , FU JINZHONG , XU YONG‐BIAO , JIN JIE‐QIONG , DING LI , MIN MI‐SOOK , CHE JING , ZHANG YA‐PING
Published: January 2012

Speciation remains a fundamental issue in biology. Herein, we report an investigation into speciation in the Rana chensinensis species complex using DNA sequence data from one mitochondrial and five nuclear genes. A phylogenetic analysis of the data revealed four major clades in the complex, and each of them was found to likely represent a species, including one cryptic species. Ecological niche models were generated from 19 climatic variables for three of the four major clades, which were represented by widespread sampling, including R. chensinensis, Rana kukunoris and the potential cryptic species. Each clade is associated with a unique ecological unit, and this indicates that ecological divergence probably drove speciation. Ecological divergence is likely related to the late Cenozoic orogenesis of the Qinghai–Tibetan Plateau. In addition, gene flow between species was detected but only in peripheral portions of the ranges of the four major clades, thus likely had little influence on the speciation processes. Discordances between mitochondrial and nuclear genes were also found; the nominal species, R. chensinensis, contains multiple maternal clades, suggesting potential mitochondrial introgression between R. chensinensis and R. kukunoris.
Hidden diversity in diatoms of Kenyan Lake Naivasha: a genetic approach detects temporal variation
Authors: STOOF‐LEICHSENRING KATHLEEN R. , EPP LAURA S. , TRAUTH MARTIN H. , TIEDEMANN RALPH
Published: January 2012

This study provides insights into the morphological and genetic diversity in diatoms occurring in core sediments from tropical lakes in Kenya. We developed a genetic survey technique specific for diatoms utilizing a short region (76–67 bp) of the ribulose‐1,5‐bisphosphate carboxylase/oxygenase large subunit (rbcL) gene as genetic barcode. Our analyses (i) validated the use of rbcL as a barcoding marker for diatoms, applied to sediment samples, (ii) showed a significant correlation between the results obtained by morphological and molecular data and (iii) indicated temporal variation in diatom assemblages on the inter‐ and intra‐specific level. Diatom assemblages from a short core from Lake Naivasha show a drastic shift over the last 200 years, as littoral species (e.g. Navicula) are replaced by more planktonic ones (e.g. Aulacoseira). Within that same period, we detected periodic changes in the respective frequencies of distinct haplotype groups of Navicula, which coincide with wet and dry periods of Lake Naivasha between 1820 and 1938 AD. Our genetic analyses on historical lake sediments revealed inter‐ and intra‐specific variation in diatoms, which is partially hidden behind single morphotypes. The occurrence of particular genetic lineages is probably correlated with environmental factors.
Deciphering cell wall integrity signalling in Aspergillus fumigatus: identification and functional characterization of cell wall stress sensors and relevant Rho GTPases
Authors: Dichtl Karl , Helmschrott Christoph , Dirr Franziska , Wagener Johannes
Published: January 2012

The fungal cell wall, a conserved and highly dynamic structure, is essential for virulence and viability of fungal pathogens and is an important antifungal drug target. The cell wall integrity (CWI) signalling pathway regulates shape and biosynthesis of the cell wall. In this work we identified, localized and functionally characterized four putative CWI stress sensors of Aspergillus fumigatus, an airborne opportunistic human pathogen and the cause of invasive aspergillosis. We show that Wsc1 is specifically required for resistance to echinocandin antifungals. MidA is specifically required for elevated temperature tolerance and resistance to the cell wall perturbing agents congo red and calcofluor white. Wsc1, Wsc3 and MidA additionally have overlapping functions and are redundantly required for radial growth and conidiation. We have also analysed the roles of three Rho GTPases that have been implicated in CWI signalling in other fungi. We show that Rho1 is essential and that conditional downregulation of rho1 or deletion of rho2 or rho4 results in severely impaired CWI. Our data indicate significant functional differences between the CWI stress sensors of yeasts and moulds.
The RGSGR amino acid motif of the intercellular signalling protein, HetN, is required for patterning of heterocysts in Anabaena sp. strain PCC 7120
Authors: Higa Kelly C. , Rajagopalan Ramya , Risser Douglas D. , Rivers Orion S. , Tom Sasa K. , Videau Patrick , Callahan Sean M.
Published: January 2012

Nitrogen‐fixing heterocysts are arranged in a periodic pattern on filaments of the cyanobacterium Anabaena sp. strain PCC 7120 under conditions of limiting combined nitrogen. Patterning requires two inhibitors of heterocyst differentiation, PatS and HetN, which work at different stages of differentiation by laterally suppressing levels of an activator of differentiation, HetR, in cells adjacent to source cells. Here we show that the RGSGR sequence in the 287‐amino‐acid HetN protein, which is shared by PatS, is critical for patterning. Conservative substitutions in any of the five amino acids lowered the extent to which HetN inhibited differentiation when overproduced and altered the pattern of heterocysts in filaments with an otherwise wild‐type genetic background. Conversely, substitution of amino acids comprising the putative catalytic triad of this predicted reductase had no effect on inhibition or patterning. Deletion of putative domains of HetN suggested that the RGSGR motif is the primary component of HetN required for both its inhibitory and patterning activity, and that localization to the cell envelope is not required for patterning of heterocysts. The intercellular signalling proteins PatS and HetN use the same amino acid motif to regulate different stages of heterocyst patterning.
Sacral nerve stimulation enhances epithelial barrier of the rectum: results from a porcine model
Authors: Meurette G. , Blanchard C. , Duchalais‐Dassonneville E. , Coquenlorge S. , Aubert P. , Wong M. , Lehur P.‐A. , Neunlist M.
Published: January 2012

Background  The mechanism of action of sacral nerve stimulation (SNS) remains largely elusive. The aims of this study were to develop a clinically relevant animal model for percutaneous SNS and to describe its effect on the epithelial barrier of the rectum.

Methods  Under general anesthesia and after percutaneous electrode placement for S3 nerve root stimulation, six pigs underwent unilateral stimulation and six bilateral stimulation. Animals were stimulated for 3 h using an external pulse generator (1–2.5 V; 14 Hz; 210 μs). Six animals underwent electrode implantation without stimulation and served as controls. Full‐thickness rectal biopsies were performed prior to and after stimulation. Paracellular permeability was evaluated by measuring sulfonic acid flux across the rectal mucosa in Ussing chambers. Histological assessment of mucosal thickness, epithelial desquamation, and mucus expression were performed.

Key Results  Percutaneous stimulation resulted in successful anal contractions whose amplitude and uniformity was enhanced following bilateral compared with unilateral stimulation. In controls, paracellular permeability significantly increased during the stimulation period whereas it remained unchanged following unilateral stimulation. In contrast, permeability was significantly reduced by bilateral stimulation. This effect was associated with a concomitant reduction in mucosal thickness and a trend toward increased amount of mucus on surface epithelium compared with controls.

Conclusions & Inferences  The development of a porcine model of percutaneous SNS revealed the ability of neuromodulation to reinforce rectal epithelial barrier. Furthermore, our results suggest that SNS could be used for treatment of gastrointestinal pathologies with reduced rectal mucosal barrier functions
Cross‐kingdom interactions matter: fungal‐mediated interactions structure an insect community on oak
Authors: Tack Ayco J. M. , Gripenberg Sofia , Roslin Tomas
Published: January 2012

Ecology Letters (2012)

Although phytophagous insects and plant pathogens frequently share the same host plant, interactions among such phylogenetically distant taxa have received limited attention. Here, we place pathogens and insects in the context of a multitrophic‐level community. Focusing on the invasive powdery mildew Erysiphe alphitoides and the insect community on oak (Quercus robur), we demonstrate that mildew–insect interactions may be mediated by both the host plant and by natural enemies, and that the trait‐specific outcome of individual interactions can range from negative to positive. Moreover, mildew affects resource selection by insects, thereby modifying the distribution of a specialist herbivore at two spatial scales (within and among trees). Finally, a long‐term survey suggests that species‐specific responses to mildew scale up to generate landscape‐level variation in the insect community structure. Overall, our results show that frequently overlooked cross‐kingdom interactions may play a major role in structuring terrestrial plant‐based communities.
Living fast and dying of infection: host life history drives interspecific variation in infection and disease risk
Authors: Johnson Pieter T. J. , Rohr Jason R. , Hoverman Jason T. , Kellermanns Esra , Bowerman Jay , Lunde Kevin B.
Published: January 2012

Ecology Letters (2012)

Parasite infections often lead to dramatically different outcomes among host species. Although an emerging body of ecoimmunological research proposes that hosts experience a fundamental trade‐off between pathogen defences and life‐history activities, this line of inquiry has rarely been extended to the most essential outcomes of host‐pathogen interactions: namely, infection and disease pathology. Using a comparative experimental approach involving 13 amphibian host species and a virulent parasite, we test the hypothesis that ‘pace‐of‐life’ predicts parasite infection and host pathology. Trematode exposure increased mortality and malformations in nine host species. After accounting for evolutionary history, species that developed quickly and metamorphosed smaller (‘fast‐species’) were particularly prone to infection and pathology. This pattern likely resulted from both weaker host defences and greater adaptation by parasites to infect common hosts. Broader integration between life history theory and disease ecology can aid in identifying both reservoir hosts and species at risk of disease‐driven declines.
BUSINESS CYCLES IN REUNIFIED GERMANY: CLOSER TOGETHER OR FURTHER APART?
Authors: Ferreira‐Lopes Alexandra , Sequeira Tiago Neves
Published: January 2012

In this article we document the features of business cycles in German states from 1970 and 2009. Specifically, we answer the question if German states are becoming more synchronized or not. All results indicate that the synchronization of cycles is stronger inside the former Western Germany and inside the former Eastern Germany. The reunification process has had a strong influence in terms of business cycle association. However, a process of cyclical convergence has begun, although slowly, after the reunification.
Estimating the evidence – a review
Authors: Friel Nial , Wyse Jason
Published: January 2012

The model evidence is a vital quantity in the comparison of statistical models under the Bayesian paradigm. This study presents a review of commonly used methods. We outline some guidelines and offer some practical advice. The reviewed methods are compared for two examples; non‐nested Gaussian linear regression and covariate subset selection in logistic regression.
PERSPECTIVES ON SPATIAL ECONOMETRICS: LINEAR SMOOTHING WITH STRUCTURED MODELS
Authors: McMillen Daniel P.
Published: January 2012

ABSTRACT Though standard spatial econometric models may be useful for specification testing, they rely heavily on a parametric structure that is highly sensitive to model misspecification. The commonly used spatial AR model is a form of spatial smoothing with a structure that closely resembles a semiparametric model. Nonparametric and semiparametric models are generally a preferable approach for more descriptive spatial analysis. Estimated population density functions illustrate the differences between the spatial AR model and nonparametric approaches to data smoothing. A series of Monte Carlo experiments demonstrates that nonparametric predicted values and marginal effect estimates are much more accurate then spatial AR models when the contiguity matrix is misspecified.
Moving from continuous dopaminergic stimulation to continuous drug delivery in the treatment of Parkinson’s disease
Authors: Gershanik O. , Jenner P.
Published: January 2012

Motor fluctuations and motor complications are a major consequence of the treatment and progression of Parkinson’s disease (PD) and they have, in particular, been linked to l‐dopa therapy. Using continuous dopaminergic stimulation (CDS) by employing longer acting dopaminergic drugs has been proposed as a means of avoiding or lowering their occurrence. However, both the preclinical and clinical evidence base suggest that this concept does not fully explain the differences between l‐dopa and dopamine (DA) agonist drugs and that their pharmacological profiles may also be important. In addition, the way in which drugs are delivered in PD appears to have a marked influence on both efficacy and side‐effect profile. As a consequence, the concept of continuous drug delivery (CDD) has arisen to explain the differences between the intermittent and continuous delivery of both l‐dopa and DA agonists. This review presents the evidence for using CDD as a working concept for the early and later stages of PD and in the treatment of motor complications and motor fluctuations. CDD as an approach to the treatment of PD may improve the outcome of therapy and explain the differences between drug classes and the delivery systems employed.
Susac syndrome: clinical characteristics and treatment in 29 new cases
Authors: Mateen F. J. , Zubkov A. Y. , Muralidharan R. , Fugate J. E. , Rodriguez F. J. , Winters J. L. , Petty G. W.
Published: January 2012

Background and purpose:  There are few clinical studies on the attempted treatments and outcomes in patients with Susac syndrome (SS) (retinocochleocerebral vasculopathy).

Methods:  A retrospective review was performed of all patients presenting with SS at the Mayo Clinic in Rochester, Minnesota, USA (1 January 1998–1 October 2011).

Results:  There were 29 cases of SS (24 women, mean age at presentation, 35 years; range, 19–65; full triad of brain, eye, and ear involvement, n = 16; mean follow‐up time, 29 months). Thirty CSF analyses were performed in 27 cases (mean protein 130 mg/dl, range 35–268; mean cell count 14, range 1–86). MRI of the brain showed corpus callosal involvement (79%), T2‐weighted hyperintensities (93%), and gadolinium enhancement (50%). Average lowest modified Rankin Scale score was 2.5 (median 2, range 0–5). Most patients (93%) received immunosuppressive treatment, with a mean time to treatment of 2 months following symptomatic onset. Treatments included intravenous methylprednisolone or dexamethasone (n = 23), oral corticosteroids (n = 24), plasma exchange (PLEX) (n = 9), intravenous immunoglobulin (IVIg) (n = 15), cyclophosphamide (n = 6), mycophenolate mofetil (n = 5), azathioprine (n = 2), and rituximab (n = 1). Most patients also received an antiplatelet agent (n = 21). Improvement or stabilization was noted in eight of 11 cases treated with IVIg in the acute period (three experienced at least partial deterioration) and eight of nine cases of PLEX treatment (one lost to follow up).

Conclusions:  Susac syndrome may be severe, disabling, and protracted in some patients. PLEX may be an adjunct or alternative therapy for patients who do not experience symptomatic improvement following steroid treatment.
The exhausting dilemmas faced by home‐care service providers when enhancing participation among older adults receiving home care
Authors: Vik Kjersti , Eide Arne H.
Published: January 2012

Scand J Caring Sci; 2012; 26; 528–536

The exhausting dilemmas faced by home‐care service providers when enhancing participation among older adults receiving home care

Older adults wish to stay at home, participate in society and manage on their own as long as possible. Many older adults will, however, eventually become dependent on care and help to maintain their daily living. Thus, to enhance activity and participation also among older adults that receive home‐based services, there is a strong need for development of knowledge‐based practice regarding participation. The specific aim of this study is to explore how service providers perceive that their working conditions influence on their possibilities to promote participation among older adults, and more specifically, how they perceive the influence of their working conditions. A purposeful sampling strategy was applied, and six focus groups with professionals in two municipalities were conducted. The focus groups comprised four and six participants of varying ages, length of working experience and professions. A total of 30 service providers participated. The data were analysed by a constant comparative method following the guidelines from Grounded Theory. The analysis identified the categories ‘encountering needs that cannot be met’, ‘expectations about participation’, ‘organisation of services’ and ‘professional standards’ influencing the service delivery. During this analytical process, ‘being on the verge’ emerged as a core category that describes the service providers’ experience of a stressful workday, i.e. when they had the feeling of working against their own professional standards and being pushed to their limits. The findings indicate how the professional standards of service providers on the whole are in line with health policy for in‐home services. Policy objectives are, however, not always followed owing to different constraints at the level of service delivery. Along the path from political ideals to the practical execution of services, external circumstances related to the organisation of services are perceived as crucial.
Identification and characterization of Rhodopseudomonas palustris TIE‐1 hopanoid biosynthesis mutants
Authors: WELANDER P. V. , DOUGHTY D. M. , WU C.‐H. , MEHAY S. , SUMMONS R. E. , NEWMAN D. K.
Published: January 2012

Hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic hopanoid lipids. Based on the phylogenetic distribution of hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. However, our ability to interpret them ultimately depends on understanding the physiological roles of hopanoids in modern bacteria. Toward this end, we set out to identify genes required for hopanoid biosynthesis in the anoxygenic phototroph Rhodopseudomonas palustris TIE‐1 to enable selective control of hopanoid production. We attempted to delete 17 genes within a putative hopanoid biosynthetic gene cluster to determine their role, if any, in hopanoid biosynthesis. Two genes, hpnH and hpnG, are required to produce both bacteriohopanetetrol and aminobacteriohopanetriol, whereas a third gene, hpnO, is required only for aminobacteriohopanetriol production. None of the genes in this cluster are required to exclusively synthesize bacteriohopanetetrol, indicating that at least one other hopanoid biosynthesis gene is located elsewhere on the chromosome. Physiological studies with the different deletion mutants demonstrated that unmethylated and C30 hopanoids are sufficient to maintain cytoplasmic but not outer membrane integrity. These results imply that hopanoid modifications, including methylation of the A‐ring and the addition of a polar head group, may have biologic functions beyond playing a role in membrane permeability.
Time‐series analysis of two hydrothermal plumes at 9°50′N East Pacific Rise reveals distinct, heterogeneous bacterial populations
Authors: SYLVAN J. B. , PYENSON B. C. , ROUXEL O. , GERMAN C. R. , EDWARDS K. J.
Published: January 2012

We deployed sediment traps adjacent to two active hydrothermal vents at 9°50′N on the East Pacific Rise (EPR) to assess the variability in bacterial community structure associated with plume particles on the timescale of weeks to months, to determine whether an endemic population of plume microbes exists, and to establish ecological relationships between bacterial populations and vent chemistry. Automated rRNA intergenic spacer analysis (ARISA) indicated that there are separate communities at the two different vents and temporal community variations between each vent. Correlation analysis between chemistry and microbiology indicated that shifts in the coarse particulate (>1 mm) Fe/(Fe+Mn+Al), Cu, V, Ca, Al, 232Th, and Ti as well as fine‐grained particulate (<1 mm) Fe/(Fe+Mn+Al), Fe, Ca, and Co are reflected in shifts in microbial populations. 16S rRNA clone libraries from each trap at three time points revealed a high percentage of Epsilonproteobacteria clones and hyperthermophilic Aquificae. There is a shift toward the end of the experiment to more Gammaproteobacteria and Alphaproteobacteria, many of whom likely participate in Fe and S cycling. The particle‐attached plume environment is genetically distinct from the surrounding seawater. While work to date in hydrothermal environments has focused on determining the microbial communities on hydrothermal chimneys and the basaltic lavas that form the surrounding seafloor, little comparable data exist on the plume environment that physically and chemically connects them. By employing sediment traps for a time‐series approach to sampling, we show that bacterial community composition on plume particles changes on timescales much shorter than previously known.
Evaluation of a Four‐drug, Three‐antibiotic, Nonbismuth–containing “Concomitant” Therapy as First‐line Helicobacter pylori Eradication Regimen in Greece
Authors: Georgopoulos Sotirios , Papastergiou Vasilios , Xirouchakis Elias , Laudi Fotini , Papantoniou Nikitas , Lisgos Phillipos , Spiliadi Chariklia , Fragou Paraskevi , Skorda Lamprini , Karatapanis Stylianos
Published: January 2012

Background:  The eradication rates of Helicobacter pylori (H. pylori) with standard treatments are decreasing worldwide as in Greece. Studies with new antibiotic combinations are needed to find better methods of eradication. Therefore, the aim of this study was to evaluate efficacy and tolerability of a 10‐day, four‐drug, three‐antibiotic, nonbismuth–containing concomitant regimen.

Materials and Methods:  This is a prospective, open‐label, multicenter study that included 131 patients infected with H. pylori. All patients were diagnosed with peptic ulcer disease or nonulcer dyspepsia by endoscopy. H. pylori infection was established by at least two positive tests among rapid urease test, gastric histology, and 13C‐urea breath test. For 10 days, all patients received esomeprazole 40 mg, amoxycillin 1000 mg, clarithromycin 500 mg, and metronidazole 500 mg, all b.d. eradication was assessed with 13C urea breath test 8 weeks after the start of treatment. Intention‐to‐treat and per‐protocol eradication rates were determined.

Results:  One hundred and twenty‐seven of the 131 patients completed the study. At intention‐to‐treat analysis, the eradication rate was 91.6% (95% confidence interval (CI), 85.5–95.7%). For the per‐protocol analysis, the eradication rate was 94.5% (95% CI, 89–97.8%). Adverse events were noted in 42 of 131 (32.1%); drug compliance was excellent with 96.9% of the patients taking more than 90% of the prescribed medication.

Conclusion:  A 10‐day concomitant regimen appears to be an effective, safe, and well‐tolerated treatment option for first‐line H. pylori eradication in Greece.
Feminism as Revolutionary Practice: From Justice and the Politics of Recognition to Freedom
Authors: Borren Marieke
Published: January 2012

In the 1980s extra‐parliamentary social movements and critical theories of race, class, and gender added a new sociocultural understanding of justice—recognition— to the much older socioeconomic one. The best‐known form of the struggle for recognition is the identity politics of disadvantaged groups. I argue that there is still another option to conceptualize their predicament, neglected in recent political philosophy, which understands exclusion not in terms of injustice, more particularly a lack of sociocultural recognition, but in terms of a lack of freedom. I draw my inspiration from Hannah Arendt's model of political action. Arendt diagnoses exclusion not solely as a mode of injustice, but as a lack of participation and public freedom. Consequently, she advocates a struggle for participation, political equality, and freedom as a strategy for emancipation or empowerment. Arendt could help feminists see that collective empowerment is made possible not by a shared identity (the target of poststructuralist critics) but by common action in the service of a particular worldly issue or common end. In other words, feminists would do well to appreciate the revolutionary quality and heritage of the feminist movement better, that is, its character as a set of practices of freedom.
Contingent Claim Pricing Using a Normal Inverse Gaussian Probability Distortion Operator
Authors: Godin Frédéric , Mayoral Silvia , Morales Manuel
Published: January 2012

Abstract

We consider the problem of pricing contingent claims using distortion operators. This approach was first developed in (Wang, 2000) where the original distortion function was defined in terms of the normal distribution. Here, we introduce a new distortion based on the Normal Inverse Gaussian (NIG) distribution. The NIG is a generalization of the normal distribution that allows for heavier skewed tails. The resulting operator asymmetrically distorts the underlying distribution. Moreover, we show how we can recuperate non‐Gaussian Black–Scholes formulas using distortion operators and we provide illustrations of their performance. We conclude with a brief discussion on risk management applications.
Short Selling Behavior and Mad Money
Authors: Hobbs Jeffrey , Keasler Terrill R. , McNeil Chris R.
Published: January 2012

We examine 1,234 buy recommendations from Jim Cramer's Mad Money television show. Consistent with prior research, we report positive abnormal returns immediately after buy recommendations, followed by a reversal, indicative of an overpricing event. We also find a marked increase in short selling. Our results show a positive association between shorting and the buy recommendations even after controlling for factors shown in the literature to influence shorting. We do not find similar effects after sell recommendations. These results suggest that short sellers act to exploit short‐term overpricing arising from behavioral biases of some investors.
Earnings Announcements: Good News for Institutional Investors and Short Sellers
Authors: Berkman Henk , McKenzie Michael D.
Published: January 2012

In this paper, we consider the trading behavior of institutional investors and short sellers around earnings announcements. The results suggest that institutional investors, and to a lesser extent short sellers, successfully anticipate earnings news. In the period immediately after the earnings announcement, both types of traders are active in the market and trade in response to the earnings announcement. In particular, short sellers are quick to increase their short positions when a company releases bad news. Institutional traders also trade in response to the news; however, they take longer to react.
Sudden Cardiac Death in Young Adults: Environmental Risk Factors and Genetic Aspects of Premature Atherosclerosis*,†
Authors: Larsen Maiken K. , Nissen Peter H. , Kristensen Ingrid B. , Jensen Henrik K. , Banner Jytte
Published: January 2012

Abstract:  Familial hypercholesterolemia (FH) is a genetic disorder that may lead to premature coronary heart disease (CHD) and sudden cardiac death (SCD). Mutations in the LDLR or APOB genes cause FH. We have screened the LDLR and the ligand‐binding region of APOB genes in 52 cases of SCD. Deceased patients were younger than 40 years of age and were suspected of having FH. The LDLR and APOB genes were examined via PCR, high‐resolution melting, and DNA sequencing. Therein, it was observed that 7.7% of the screened patients exhibited a rare sequence variant in the LDLR gene, with 5.7% suspected of being pathogenic mutations. Lipid profiles and genetic testing for FH could be considered when autopsy reveals significant atherosclerosis of the coronary arteries in young adults. First‐degree family members are advised to seek medical advice and testing to determine their own risks of atherosclerosis to prevent premature CHD and SCD.
Preparation of Pyrolysis Reference Samples: Evaluation of a Standard Method Using a Tube Furnace
Authors: Sandercock P. Mark L.
Published: January 2012

Abstract:  A new, simple method for the reproducible creation of pyrolysis products from different materials that may be found at a fire scene is described. A temperature programmable steady‐state tube furnace was used to generate pyrolysis products from different substrates, including softwoods, paper, vinyl sheet flooring, and carpet. The temperature profile of the tube furnace was characterized, and the suitability of the method to reproducibly create pyrolysates similar to those found in real fire debris was assessed. The use of this method to create proficiency tests to realistically test an examiner’s ability to interpret complex gas chromatograph–mass spectrometric fire debris data, and to create a library of pyrolsates generated from materials commonly found at a fire scene, is demonstrated.
Functional study of acetylcholinesterase genes in Bombyx mori ovary cells using RNA interference
Authors: Cao Y. Q. , Liu L. H. , Wang J. M. , Wang Y. H. , Shen W. D. , Li B.
Published: January 2012

Acetylcholinesterase (AChE) plays a key role in neurotransmission, in which it maintains the transmission of nerve impulses by catalyzing acetylcholine in the neuronal synapse. Acetylcholinesterase in Lepidoptera is encoded by two ace genes, ace1 and ace2. In this study, we used RNA interference to individually knock down the expression of ace1 or ace2 in a Bombyx mori (L.) (Lepidoptera: Bombycidae) cell line (BmN) to explore their functions and relationships. Knockdown efficiency was confirmed using quantitative real‐time PCR. We also monitored transcription levels of ace1 and ace2 at different time points after B. mori nucleopolyhedrovirus (BmNPV) infection. We found that when the expression of ace1 was knocked down to 37.5%, the expression of ace2 increased by 66%; when ace2 expression was reduced to 33.4%, the ace1 expression was similarly reduced to 26.7%. Acetylcholinesterase activity was decreased to 86.2% when ace2 expression was inhibited. However, no significant difference was observed in AChE activity when ace1 expression was knocked down. After BmNPV infection, ace1 expression was gradually increasing, whereas ace2 expression was gradually decreasing. Our study indicates that ace2 plays an important compensatory role for the loss of ace1 in maintaining AChE activity by increasing its expression level. In addition, ace2 may also regulate transcription of ace1. Overall, our findings help elucidate the relationship between the two ace genes in Lepidoptera.
Foliar N concentration and δ15N signature reflect the herb layer species diversity and composition in oak‐dominated forests
Authors: Hofmeister Jeňýk , Hošek Jan , Bůzek František , Roleček Jan
Published: January 2012

Questions

Is the herb layer species diversity and composition in species‐rich oak‐dominated forests related to the (i) soil nitrogen (N) pool, (ii) foliar N concentration, and (iii) foliar 15N/14N isotope ratio (δ15N), as indicators of the N status in ecosystems? How do they correspond to the Ellenberg indicator value for N (EIV‐N) of the herb layer vegetation?

Location

Three areas in central Bohemia (Czech Republic) underlain by different geological substrates.

Methods

We assessed the herb layer species composition in nine oak‐dominated forests growing on different substrates, in relation to both soil nutrient pools and oak leaf nutrient concentrations. Data on the herb layer vegetation composition were collected in 16 square plots (25 m2 each) distributed according to a fixed stratified random design at each site. Soil nutrient pools were calculated on the basis of nutrient concentration and weight of quantitative soil samples taken from six defined depth strata at each of two or three 0.5‐m2 pits at each site. Foliar analyses were based on samples of 150 leaves from the upper part of the canopy of five oaks at each site.

Results

The mean Shannon diversity index of herb layer vegetation was negatively related to the mean foliar Ntot. concentration, whereas the mean recovery rate (RR) of herb layer species was strongly positively related to foliar δ15N signatures and, less markedly, to the soil Ntot. pool. Similarly, both the foliar δ15N and the soil Ntot. pool were positively correlated with mean‐weighted EIV‐N in the herb layer vegetation.

Conclusions

The herb layer species diversity and composition was significantly related to N availability at our study sites. Foliar N concentration and the δ15N signature may reliably indicate: (i) the current N status of oak‐dominated forests, in accordance with previous published findings; and (ii) the consequences of that N status for the herb layer species diversity and composition. Foliar δ15N may also be used to detect the susceptibility of an ecosystem to the spread of a few species with high colonization ability in the herb layer, at the expense of other forest species.
Garden waste deposits as a source for non‐native plants in mixed deciduous forests
Authors: Rusterholz Hans‐Peter , Wirz Dino , Baur Bruno
Published: January 2012

Question

Is illegal garden waste dumping in mixed deciduous forests a source for establishment of non‐native plants in deciduous forests?

Location

Northwestern Switzerland.

Methods

We quantified the amount of illegally dumped garden waste at 20 sites over 1 yr and compared the soil conditions, species richness and abundance of plants in the ground vegetation at disposal sites with those at 20 control sites in urban deciduous forests.

Results

We found that illegal garden waste dumping frequently occurs in urban forests. At single sites, 0.1–12.5 m3 (mean: 2.6 m3) garden waste was dumped per month, resulting in a total annual amount of 2.2–35.8 m3 (mean: 17.8 m3) waste deposited. Thirty‐seven of the 163 plant species recorded were not native to Switzerland. All 37 non‐native species were recorded in waste disposal sites, but only three of them in control sites. Thus, garden waste dumping sites harboured a larger number of non‐native species than control sites, but the two groups of sites did not differ in number of native species. The species composition also differed between disposal and control sites: larger proportions of species typical of disturbed habitats, more therophytes and species with autochorous seed dispersal were recorded in disposal sites than in control sites.

Conclusions

We provide evidence that numerous non‐native horticultural plant species escape from dumping sites and colonize forests. There is an urgent need to increase awareness of garden owners concerning problems associated with illegal garden waste dumping.
Fingerprinting TCE in a Bedrock Aquifer Using Compound‐Specific Isotope Analysis
Authors: Lojkasek‐Lima Paulo , Aravena Ramon , Parker Beth L. , Cherry John A.
Published: January 2012

A dual isotope approach based on compound‐specific isotope analysis (CSIA) of carbon (C) and chlorine (Cl) was used to identify sources of persistent trichloroethylene (TCE) that caused the shut‐down in 1994 of a municipal well in an extensive fractured dolostone aquifer beneath Guelph, Ontario. Several nearby industrial properties have known subsurface TCE contamination; however, only one has created a comprehensive monitoring network in the bedrock. The impacted municipal well and many monitoring wells were sampled for volatile organic compounds (VOCs), inorganic parameters, and CSIA. A wide range in isotope values was observed at the study site. The TCE varies between −35.6‰ and −21.8‰ and from 1.6‰ to 3.2‰ for δ13C and δ37Cl, respectively. In case of cis‐1,2‐dichloroethene, the isotope values range between −36.3‰ and −18.9‰ and from 2.4‰ to 4.7‰ for δ13C and δ37Cl, respectively. The dual isotope approach represented by a plot of δ13C vs. δ37Cl shows the municipal well samples grouped in a domain clearly separate from all other samples from the property with the comprehensive well network. The CSIA results collected under non‐pumping and short‐term pumping conditions thus indicate that this particular property, which has been studied intensively for several years, is not a substantial contributor of the TCE presently in the municipal well under non‐pumping conditions. This case study demonstrates that CSIA signatures would have been useful much earlier in the quest to examine sources of the TCE in the municipal well if bedrock monitoring wells had been located at several depths beneath each of the potential TCE‐contributing properties. Moreover, the CSIA results show that microbial reductive dechlorination of TCE occurs in some parts of the bedrock aquifer. At this site, the use of CSIA for C and Cl in combination with analyses of VOC and redox parameters proved to be important due to the complexity introduced by biodegradation in the complex fractured rock aquifer. It is highly recommended to revisit the study when the municipal well is back into full operation.