bluuebunny/crossref_metadata_2025 huggingface dataset:
The ecology and mechanisms of overflow‐mediated dispersal in a rock‐pool metacommunity
Authors: Pellowe‐Wagstaff Kara E. , Simonis Joseph L.
Published: February 2014

The dispersal of organisms in fragmented habitats connects spatially separated local populations at the regional, metapopulation scale, with potential consequences for spatial population dynamics and persistence. As any dispersing organism is engaged in trophic interactions as well, dispersal also connects local food webs at the regional scale, and differential dispersal among taxa of different trophic levels has the potential to strongly influence spatial food‐web dynamics.

We used a combination of field surveys and experiments to test the significance of passive dispersal via overflowing water for population and food‐web dynamics in a system of freshwater rock pools onAppledoreIsland,Maine,U.S.A. The rock pools contain a three‐trophic‐level food chain consisting of phytoplankton (primarily chlorophyte algae), grazer zooplankton (two species of Cladocera) and a predatory insect (Trichocorixa), all of which are passively dispersed between rock pools when the pools overflow during rain events.

During the summers of 2010 and 2011, rain events were observed (on average) every two and a half days. Three‐quarters of rain events generated overflows, and observed overflow rates varied over four orders of magnitude (0.5–474 mLs−1). A Monte Carlo simulation showed that, on average, a pool is expected to overflow 5.6 times during a summer.

Despite all three taxa dispersing in overflows, and dispersing more at higher flow rates, a mesocosm experiment showed that dispersal rates decreased significantly with increasing trophic level, such thatTrichocorixadispersed less than cladocerans, which dispersed less than phytoplankton. Results from a follow‐up experiment suggest that this decrease in dispersal is primarily due to organisms at higher trophic levels being more able to avoid currents, rather than an ability to swim more strongly against currents.

Finally, we conducted a field experiment to determine the influence of overflows on population and food‐web dynamicsin situ. Populations in pools that were part of experimental overflows were significantly more variable than nearby populations that were not in the overflow, and taxa at all three trophic levels were influenced similarly by the overflows.

This study demonstrates that passive dispersal of aquatic organisms among habitat patches is likely to occur at different rates for different taxa, which may have strong effects on spatial food‐web dynamics.
Modelling epilithic biofilms combining hydrodynamics, invertebrate grazing and algal traits
Authors: Graba Myriam , Sauvage Sabine , Majdi Nabil , Mialet Benoît , Moulin Frédéric Y. , Urrea Gemma , Buffan‐Dubau Evelyne , Tackx Michèle , Sabater Sergi , Sanchez‐Pérez José‐Miguel
Published: February 2014

This model of stream epilithic biofilm biomass dynamics is based on the system of equations from Uehlinger et al. () and the term for autogenic detachment of biofilm from Boulêtreau et al. (). Its new features are (i) a mathematical term based on estimated feeding activity of biofilm‐dwelling invertebrates, (ii) local hydrodynamics considered as the principal factor governing algal traits and biofilm structure and (iii) a variable degree of parameterisation that was adjusted to biofilm biomass conditions.

Biofilm biomass was monitored over a one‐year period in the Garonne river in France (September 2008–2009). An allometric approach was used to estimate the feeding activity of biofilm‐dwelling invertebrates based on their energetic requirements. Diatom functional diversity was also monitored to find how it varied with overall biofilm growth patterns. The one‐year monitoring period was divided into six biofilm biomass cycles, with each cycle consisting of a phase of biofilm growth as the main process, followed by detachment.

This model reproduced the observed data as a complex of biofilm growth/detachment cycles using different sets of empirical parameters which allowed (i) the dominant processes involved in each biofilm cycle to be evaluated and (ii) the six cycles of biofilm growth/detachment to be reproduced. This accounted for the observed patterns more effectively than a parameterisation using a single set of empirical parameters.

High flow had a severe effect on biofilm dynamics through chronic and catastrophic detachment. Presumably as a result, assemblages of diatoms shifted towards species that were firmly attached and protected by mucilage.

During low flow (and when temperature was high), biofilm dynamics was mainly affected by autogenic detachment and grazer activity. The grazing pressure of the dominant biofilm‐dwelling invertebrates (Nematoda and larvae of Chironomidae and Trichoptera) was fairly low (a maximum of 6% of biofilm biomass ingested daily); nevertheless, their presence in the biofilm seemed to favour biofilm autogenic detachment.
Beavers (Castor canadensis) influence habitat for juvenile salmon in a largeAlaskan river floodplain
Authors: Malison Rachel L. , Lorang Mark S. , Whited Diane C. , Stanford Jack A.
Published: February 2014

Our aim was to determine how beavers affect habitats and food resources for juvenile salmon in theKwethlukRiver in westernAlaska.

Habitat modification by beavers was quantified using 3 years of satellite imagery to assess the amount and spatial distribution of potential juvenile rearing habitat. Macroinvertebrate community composition and juvenile salmon abundance in beaver ponds, spring brooks with and without upstream beaver dams, and main channel shorelines were quantified to determine beaver influence. Presence of beaver dams and time‐series measures of water levels were used to assess hydrological connectivity and fish access between the sites and the river as modified by beavers.

Of the off‐channel aquatic habitat, 87.5% was altered by beavers damming spring brooks. All beaver‐free and beaver‐influenced juvenile salmon habitats had similar physical characteristics [by non‐metric multidimensional scaling (NMDS) ordination], indicating that all are suitable as juvenile salmon rearing habitat.

Aquatic macroinvertebrate community composition differed between beaver ponds and spring brooks (byNMDSordination) with differences driven by larval stoneflies in spring brooks compared to cladocerans, copepods and freshwater clams in beaver ponds.

Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon were predominant in all habitat types except late‐successional ponds. Total fish species and salmon species richness was 2–3× higher, the proportion of young‐of‐the‐year salmon was over 50% compared to <5%, and densities of juvenile salmon were 5–7× higher in spring brooks and early‐successional ponds compared to late‐successional ponds.

Early‐successional ponds had high hydrological synchrony values (closely tracking water fluctuations in the main channel), while mid‐ and late‐successional ponds, being farther from the main channel and with more dams blocking flow paths, had lower and highly variable synchrony values. Almost no movement of juvenile salmon occurred past dams at base flow. However, summer and autumn flooding mediated movement past dams, allowing individuals to ‘escape’ or enter early‐successional ponds.

Beavers reduced habitat connectivity and added variability to macroinvertebrate assemblages within habitats by damming floodplain spring brooks. Nonetheless, juvenile salmon were able to effectively inhabit and move between early‐successional ponds and spring brooks in theKwethlukRiver, although the presence of beaver dams strongly limited the use of late‐successional ponds on the large alluvial river floodplain.
Does post‐grazing sward height influence sward characteristics, seasonal herbage dry‐matter production and herbage quality?
Authors: Ganche E. , O'Donovan M. , Delaby L. , Boland T. M. , Kennedy E.
Published: February 2014

Extending the grazing season through the production and utilization of high‐quality forage is a key objective in grassland‐based dairy production systems. Grazing swards to a low post‐grazing sward height (PGSH) is a strategy for improving grass utilization. A grazing experiment conducted in Ireland investigated immediate and subsequent effects ofPGSHon sward production, utilization and structural characteristics. Swards were grazed to 2·7 cm (severe; S1) or 3·5 cm (moderate; M1) from 10 February to 18 April 2010 (Period 1; P1). From 19 April, each P1 paddock was halved and grazed to either 3·8 cm (S2) or 4·8 cm (M2), until 30 October (Period 2; P2). The first grazing rotation was +7 d on S1 swards compared with M1 swards (45 d), due to greater herbage utilization (+0·22). Herbage production during P1 was not affected byPGSHbut a severePGSHduring this period reduced subsequent herbage production: 13·9 (S1) vs. 15·5 t dry matter (DM) ha−1(M1) by the end of the study. Leaf proportion was increased (+0·10) on S2 swards compared with M2 swards, but M2 swards produced 1·2 tDMha−1more herbage during P2. Despite the relatively lower level of sward utilization obtained from moderate grazing in P1 (3·5 cm) and P2 (4·5–5·0 cm), such levels ofPGSHincreasedDMproduction while maintaining sward quality, compared with severe grazing (2·7 cm in P1 and 3·5–4·0 cm in P2).
European mitochondrial haplogroups are not associated with hepatitis C virus (HCV) treatment response in HIV/HCV‐coinfected patients
Authors: Guzmán‐Fulgencio M , Rallón N , Berenguer J , Fernández‐Rodríguez A , Soriano V , Miralles P , Jiménez‐Sousa MA , Restrepo C , López JC , García‐Álvarez M , Aldámiz T , Benito JM , Resino S
Published: February 2014

Objectives

Mitochondria are multifunctional organelles with a key role in the innate immune response against viral infections. Mitochondrial DNA (mtDNA) haplogroups have been related to AIDS progression and CD4 T‐cell recovery in HIV‐infected patients, and to a delay in the development of liver fibrosis in HIV/hepatitis C virus (HCV)‐coinfected patients. We performed a study to investigate whether mtDNA haplogroups may be associated with HCV treatment response in HIV/HCV‐coinfected patients on pegylated interferon (pegIFN) plus ribavirin (RBV).

Methods

We performed a retrospective study in 304 patients who completed a course of HCV therapy. mtDNA polymorphisms were genotyped using Sequenom's MassARRAY platform. The interleukin‐28B (IL‐28B) polymorphism (rs12980275) was genotyped using the GoldenGate® assay. Sustained virological response (SVR) was defined as an undetectable HCV viral load at week 24 after the end of treatment. The statistical analysis was carried out using on‐treatment data.

Results

The SVR rates were 52.6% (160 of 304) for all patients, and 37.8% (46 of 201) for patients with HCV genotype 1 or 4 vs. 81.4% (83 of 102) for patients with HCV genotype 2 or 3 (P < 0.001). No significant associations were found between mtDNA haplogroup and SVR when all patients were included in the analysis and when patients were stratified by HCV genotype (i.e. those with genotypes 1/4 and 2/3 analysed separately) or IL‐28B rs12980275 genotype.

Conclusions

European mtDNA haplogroups were not related to HCV treatment response in HIV/HCV‐coinfected patients on pegIFN‐α/RBV therapy.
A quantitative evaluation method of skin texture affected by skin ageing using replica images of the cheek
Authors: Ryu J. H. , Seo Y. K. , Boo Y. C. , Chang M. Y. , Kwak T. J. , Koh J. S.
Published: February 2014

Synopsis

Objective

Skin texture is a fine structure of skin surface where the hill and furrow were crossed to form a star shape. This study was performed to establish a quantitative evaluation method of skin texture affected by skin ageing using replica images of the cheek.

Methods

After producing replicas of the left cheek areas of 80 female subjects, representative replica images were chosen to establish six‐level facial skin texture index. Using this new index, skin texture of different‐aged subjects was visually assessed by multiple examiners. The number of star configurations was also analysed using the same replica images. Other factors contributing to skin texture, such as skin elasticity, roughness, dermal density, moisture and gloss, were also analysed.

Results

The concordance between skin texture scores evaluated by three researchers was high (0.896), and there was a high correlation between skin texture score and age (r = 0.642). The number of star configurations showed high correlations with skin texture scores (r = 0.753) and with age (r = 0.776). Skin texture scores were highly correlated with skin roughness and dermal density, but not with moisture, gloss and elasticity.

Conclusion

This study suggests that visual grading of skin texture score based on new facial skin texture index and quantification of star configurations will be useful in evaluating skin ageing.
Attitudes to English teachers' accents in the Gulf
Authors: Buckingham Louisa
Published: February 2014

While the spread of English as a lingua franca has led to calls for multidialectal competence, EFL learners often still consider inner circle native English speaker (NES) pronunciation as their learning goal, and may profess a preference for particular teachers based on their NES or non‐native English speaker (NNES) status. This study investigates whether a teacher's NES/NNES status may affect Omani students' level of confidence towards the teacher. Using an adapted matched‐guise technique with almost 350 students, the study reveals a preference for speakers and accents students understand to be from the UK, although students also responded favourably to Arabic native speakers. Where the NES/NNES variable remained constant, no significant difference in student's ratings of the teacher was found.
Aldehyde reductase activity in the antennae of Helicoverpa armigera
Authors: Guo H. , Del Corso A. , Huang L‐Q. , Mura U. , Pelosi P. , Wang C‐Z.
Published: February 2014

In the present study, we identified two aldehyde reductase activities in the antennae of Helicoverpa species, NADH and NADPH‐dependent activity. We expressed one of these proteins of H. armigera, aldo‐keto reductase (AKR), which bears 56% identity to bovine aldose reductase, displays a NADPH‐dependent activity and is mainly expressed in the antennae of adults. Whole‐mount immunostaining showed that the enzyme is concentrated in the cells at the base of chemosensilla and in the nerves. The enzyme activity of H. armigera AKR is markedly different from those of mammalian enzymes. The best substrates are linear aliphatic aldehydes of 8–10 carbon atoms, but not hydroxyaldehydes. Both pheromone components of H. armigera, which are unsaturated aldehydes of 16 carbons, are very poor substrates. Unlike mammalian AKRs, the H. armigera enzyme is weakly affected by common inhibitors and exhibits a different behaviour from the action of thiols. A model of the enzyme suggests that the four cysteines are in their reduced form, as are the seven cysteines of mammalian enzymes. The occurrence of orthologous proteins in other insect species, that do not use aldehydes as pheromones, excludes the possibility of classifying this enzyme among the pheromone‐degrading enzymes, as has been previously described in other insect species.
Refractory sickle cell leg ulcer: is heparan sulphate a new hope?
Authors: Hayek Shady , Dibo Saad , Baroud Joe , Ibrahim Amir , Barritault Denis
Published: February 2014

Patients with sickle cell disease are known to have recurrent lower extremity ulcers that have a high pain score and are resistant to conventional means of wound therapy. This study reports the successful use of synthetic heparan sulphate (Cacipliq20®, OTR3, Paris, France) in the treatment of a sickle cell ulcer that had failed to respond to several other means of treatment. Therapeutic success was assessed by complete wound coverage and vast improvement in pain score. This is the first study to report use of heparan sulphate in sickle cell ulcers.
Conditional Cash Transfers and the Effect on Recent Murder Rates in Brazil and Mexico
Authors: Lance Justin Earl
Published: February 2014

This article examines whether conditional cash transfer (CCT) programs have had a significant effect on reducing murder rates in Mexico and Brazil, using time-series municipal-level data on murders in both countries. The findings, over the period 2005–8, show that the greater the proportion of beneficiaries enrolled in a CCT program in each municipality, the lower the number of murders. There are, however, important differences between the two countries, with a much larger effect in Brazil than in Mexico. This holds even when controlling for GDP and levels of development.
The Organization of the Executive Branch in Latin America: What We Know and What We Need to Know
Authors: Bonvecchi Alejandro , Scartascini Carlos
Published: February 2014

This article proposes a research agenda for the organization of the executive branch in Latin America by reviewing the literature on the U.S. and Latin American presidencies and outlining the research gap between them. The study finds that while strong, regionwide patterns have been established about cabinets in Latin America, research is lagging behind on the presidential center, presidential advisory networks, and their effects in policymaking. The article sets forth a series of research questions and suggests a combination of quantitative, social network, and case study strategies to address them.
Effect of the Amount of H2O on the Crystallization of TiO2 Films Prepared from Alkoxide Solutions Containing Acetylacetone
Authors: Uchiyama Hiroaki , Okada Momoto , Kozuka Hiromitsu
Published: February 2014

Sol–gel‐derived TiO2 films were prepared by dip‐coating from Ti(OC3H7i)4–CH3COCH2COCH3–HNO3–H2O–C2H5OH solutions, and the effect of the H2O content in solutions on the crystallization of TiO2 films during the heat treatment at 800°C was discussed. The crystalline phase, crystallite size, grain size, and refractive index of the TiO2 films depended on the H2O/Ti(OC3H7i)4 mole ratios (x) in the coating solutions. Highly dense and crystalline rutile films were obtained at x = 0.5–10, where the crystallites and grains became larger with increasing x. The further increase in x from 10 to 50 reduced the crystallite size and refractive index of the films, where anatase phase appeared at x = 30–50.
Nature of Pd and Ti Metals in the Structure of CMAS Glass and Ceramics
Authors: Golovchak Roman , Davis Mark J. , Vullo Paula , Saiyasombat Chatree , Jain Himanshu
Published: February 2014

The structure of electrically conductive CMAS‐TiO2‐Pd glass and ceramics was investigated by transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), X‐ray photoelectron spectroscopy (XPS), X‐ray absorption near‐edge spectroscopy (XANES), and extended X‐ray absorption fine structure spectroscopy (EXAFS). The XANES spectra of Ti do not show any significant difference between the glasses ceramized in air or in a reducing “forming” gas, as well as between Pd‐containing versus Pd‐free samples, nor between surface versus bulk of the glass‐ceramic samples. However, EXAFS and XANES data recorded at the Pd K‐edge show significant dependences on whether the glass‐ceramic was ceramized in air or in “forming” gas. The XPS spectra of Ti 2p core‐level electrons for glasses ceramized in air or “forming” gas also show a strong difference depending on whether the samples did or did not contain Pd. STEM mapping confirms the existence of grains in the form of main crystalline phases identified with XRD, and also reveals the existence of Pd nanoparticles in glasses ceramized in both air and in “forming” gas.
Forecasts in IPO Prospectuses: The Effect of Corporate Governance on Earnings Management
Authors: Cormier Denis , Lapointe‐Antunes Pascale , McConomy Bruce J.
Published: February 2014

Prior research suggests that managers may use earnings management to meet voluntary earnings forecasts. We document the extent of earnings management undertaken within Canadian Initial Public Offerings (IPOs) and study the extent to which companies with better corporate governance systems are less likely to use earnings management to achieve their earnings forecasts. In addition, we test other factors that differentiate forecasting from non‐forecasting firms, and assess the impact of forecasting and corporate governance on future cash flow prediction. We find that firms with better corporate governance are less likely to include a voluntary earnings forecast in their IPO prospectus. In addition, we find that while IPO firms use accruals management to meet forecasts; the informativeness of the discretionary accruals depends on whether or not the firm would have missed its forecast without the use of discretionary accruals.
The Impact of Earnings Guidance Cessation on Information Asymmetry
Authors: Hu Bill , Hwang Joon Ho , Jiang Christine
Published: February 2014

This paper studies the impact of quarterly earnings guidance cessation on information asymmetry using a large sample of firms during the years 2002–11. After earnings guidance cessation, information asymmetry may increase because less information is provided to the market. Alternatively, information asymmetry may decrease if managers have less pressure to manage reported earnings to meet guidance numbers. Our study shows guidance cessation significantly reduces information asymmetry compared to matched non‐guiders and guidance maintainers. We also find that firms engage in less earnings management after guidance cessation, especially for firms that had provided guidance on a persistent basis.
Market Implied Ratings and Financing Constraints: Evidence from US Firms
Authors: Tsoukas Serafeim , Spaliara Marina‐Eliza
Published: February 2014

Financing constraints have been found to play an important role in several aspects of firm behavior, but no attention has been given to their effects on credit ratings. In this paper we analyze a unique and comprehensive data set for US firms rated by Fitch over the period 2001–07. We employ Fitch's market implied ratings derived from bond and equity prices. The analysis finds evidence that financial variables are more important in predicting credit ratings for firms likely to face financing constraints. We conclude that the financing constraint is an important dimension in the market implied ratings process. Our findings are of relevance to managers, investors and rating agencies seeking to understand the mechanism through which financing constraints affect credit ratings.
Thresholds and the species–area relationship: a synthetic analysis of habitat island datasets
Authors: Matthews Thomas J. , Steinbauer Manuel J. , Tzirkalli Elli , Triantis Kostas A. , Whittaker Robert J.
Published: February 2014

Aim

The application of island biogeography theory in habitat fragmentation research assumes a simple relationship between species richness and fragment area. However, previous work has suggested that in some cases thresholds can be detected, at which the form of the island species–area relationship (ISAR) changes abruptly. Piecewise regression has been advocated as a suitable statistical technique to model such thresholds. Here we first provide a comparative analysis of piecewise regression models to determine the prevalence and type of thresholds in habitat island ISARs. Second, we evaluate piecewise regression as a method for locating thresholds in the ISAR, with particular emphasis on the implications of data transformation.

Location

World‐wide.

Methods

Seventy‐six habitat island datasets were sourced from the literature. An information theoretic approach was employed to compare linear regression ISAR models with piecewise regression models. The models were applied to untransformed (species–area), semi‐log (species–log area) and log–log (log species–log area) data. Three types of piecewise regression models were evaluated: continuous, discontinuous and zero slope. Model performance was compared using the Akaike information criterion. We also examined the influence on model performance of taxon, number of habitat islands, and area of smallest island.

Results

Linear regression models performed best, although piecewise models were preferred in a number of cases. Cases in which no model was significant were most prevalent in untransformed space relative to the semi‐log and log–log transformations. Piecewise fits were more prevalent in datasets with a larger numbers of islands.

Main conclusions

Data transformation is a key part of model selection and needs to be explicitly considered, especially in terms of drawing inferences from models. Piecewise models, even if selected as the favoured model in our analyses, were often ecologically unintelligible in relation to area alone. When detected, breakpoint values ranged over five orders of magnitude, although with one exception all were under 50 ha. Our findings highlight the limitations of using individual threshold values to inform conservation practice.
‘Short‐term treatment with methotrexate does not affect microvascular endothelial function in patients with psoriasis’
Authors: Gyldenløve M. , Jensen P. , Løvendorf M.B. , Zachariae C. , Hansen P.R. , Skov L.
Published: February 2014

Background

Psoriasis is associated with increased risk of cardiovascular disease (CVD), possibly due to chronic low‐grade systemic inflammation. Systemic anti‐inflammatory treatment might reduce the risk of CVD.

Objective

Our aim was to investigate if short‐term treatment with methotrexate influences microvascular endothelial function (MEF), an early surrogate marker of atherosclerosis, in patients with psoriasis.

Methods

We prospectively studied a hospital cohort of patients with psoriasis. Measurements of MEF were performed with the Endo‐PAT2000© device at baseline and after 8–10 weeks of treatment with methotrexate. At the same time points, we recorded anamnestic information, measured body mass index (BMI), waist and hip circumferences and blood pressure, and drew blood samples (lipid profile, HbA1 and hs‐CRP). Psoriasis severity was evaluated by psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI).

Results

A total of 32 patients with psoriasis were included. Median age was 46 (range 18–82) years, and 50% were men. Twenty‐seven patients completed the study. After 8–10 weeks, median PASI had decreased significantly by 6.2 (from 9.8 to 3.6), and DLQI had decreased by 7 (from 9 to 2). No significant changes were observed in MEF, expressed by reactive hyperaemia index and augmentation index. Also, we saw no significant changes in BMI, waist–hip ratio, blood pressure and blood samples.

Conclusion

Short‐term treatment with methotrexate did not affect MEF in patients with psoriasis. Further studies are warranted.
Radiotherapy of morphea‐type basal cell carcinoma: results in 127 cases
Authors: Caccialanza M. , Piccinno R. , Çuka E. , Alberti Violetti S. , Rozza M.
Published: February 2014

Background

The morphea‐type basal cell carcinoma (MBCC) is a rare form of basal cell carcinoma (BCC) with lower response to treatments than other types of BCC.

Objective

To evaluate the role of radiotherapy (RT) in the therapeutic strategy of MBCC.

Methods

A retrospective study was performed on 127 patients affected with MBCC, who underwent RT in the period 1982–2013. RT was delivered with conventional energies ranging from 50 to 120 kV and the administration of a total dose ranging from 40 to 70 Gy (mean 56.17 Gy). The irradiated fields included a margin of 1.5 cm around the lesion.

Results

The median follow‐up time was 29 months (range 1–324 months). Complete remission was observed in 122 patients (96.06%), partial remission in one (0.78%). Three cases were non‐responsive (2.36%). In one case (0.78%), the lesion failed to heal after RT, since the onset of radiodermatitis histologically ascertained. The cure rate was 81.08% after 5 years and 78.02% after 10 years from the end of RT. Twelve cases relapsed (10.2%).

Conclusion

Because of the frequent diagnostic delay and its ill‐defined margins, MBCC is difficult to cure. Our results after 5 years from RT (cure rate 81.08%) are more satisfactory respect to the others reported in the literature (69% and 72.3%), but less good than those obtained in other forms of primary malignant neoplasms of the skin (92.43%). Nevertheless, we consider that RT plays an important role in the therapeutic strategy of MBCCs. In fact, it can be applied easily in elderly patients, and in peculiar localization of the disease (eyelid, nose and ear), without being invasive.
Evolution in the sabre‐tooth cat, Smilodon fatalis, in response to Pleistocene climate change
Authors: Meachen J. A. , O'Keefe F. R. , Sadleir R. W.
Published: February 2014

The late Pleistocene was a time of environmental change, culminating in an extinction event. Few fossil localities record a temporal series of carnivore fossil populations from this interesting interval as well as Rancho La Brea (RLB). We analysed mandibles of Smilodon fatalis from RLB using 2‐D geometric morphometrics to examine whether, and how, mandibular shape changes through time. Smilodon fatalis shows mandibular evolution with oscillations between a small, ancestral‐type morph in pits 77 (≈37 Kybp) and 2051 (≈26 Kybp), a larger, more derived morph in pits 91 (≈28 Kybp) and 61‐67 (≈13.6 Kybp), and an intermediate morph from pit 13 (≈17.7 Kybp). These oscillations end in pit 61‐67, with greatest body size, and are estimated to have its widest gape and lowest bite force. Additionally, variation is lowest in pit 61‐67, which was deposited concurrent with the Bølling–Allerød warming event, which may have important implications for the timing or conditions during the extinction event. Contra to a temporal Bergmann's rule, such rapid warming events appear to be correlated with larger, derived, morphologies whereas static, cooler, climates correlate with gracile, ancestral morphologies.
Autofluorescence imaging endoscopy for predicting acid reflux in patients with gastroesophageal reflux disease
Authors: Wang Weifeng , Uedo Noriya , Yang Yunsheng , Peng Lihua , Bai Diane , Lu Zhongsheng , Fan Kaichun , Wang Juan , Wang Xiaoxiao , Zhao Yunlong , Yu Zhiping
Published: February 2014

Background and Aim

Endoscopic diagnosis of gastroesophageal reflux disease (GERD) remains challenging. Autofluorescence imaging (AFI) can identify indistinct mucosal lesions; however, its ability to diagnose GERD has not been determined. This study aimed to compare the diagnostic capabilities of standard white light imaging (WLI) and AFI using pH/impedance testing as gold standard.

Methods

In this prospective observational trial, 95 consecutive patients with classic reflux symptoms were screened in two tertiary care referral hospitals and 82 were included. GerdQ questionnaire was administered to each patient. Endoscopy with WLI and AFI, and ambulatory 24‐h pH/impedance monitoring were performed. Erosive esophagitis on WLI was defined as positive for GERD, whereas on AFI endoscopy, the appearance of one or more longitudinal purple lines > 1 cm was defined as indicative of GERD. We assessed the diagnostic capacities of each method, as well as inter‐observer agreement on AFI findings. We also looked at factors associated with having a positive AFI finding.

Results

The sensitivity and accuracy of AFI (77% and 67%, respectively) in detecting GERD were higher than those of WLI (21% and 52%, respectively), although the specificity of AFI (53%) was lower than that of WLI (97%); McNemar test showed a significant difference (P = 0.000). Inter‐observer reliability analysis of AFI findings indicated substantial agreement (Kappa = 0.630, P = 0.000). Multivariate analysis showed that abnormal AFI findings significantly correlated with positive pH/impedance result (odds ratio = 0.242, 95% confidence interval = 0.087–0.673, P = 0.007).

Conclusions

AFI can reveal GERD‐related mucosal changes, invisible on conventional WLI, thus improve the endoscopic diagnosis of GERD.
Hydrogen sulfide protects blood–brain barrier integrity following cerebral ischemia
Authors: Wang Yali , Jia Jia , Ao Guizhen , Hu Lifang , Liu Hui , Xiao Yunqi , Du Huaping , Alkayed Nabil J. , Liu Chun‐Feng , Cheng Jian
Published: February 2014

By using two structurally unrelated hydrogen sulfide (H2S) donors 5‐(4‐methoxyphenyl) ‐3H‐1, 2‐dithiole‐3‐thione (ADT) and sodium hydrosulfide (NaHS), this study investigated if H2S protected blood–brain barrier (BBB) integrity following middle cerebral artery occlusion (MCAO). ICR mice underwent MCAO and received H2S donors at 3 h after reperfusion. Infarction, neurological scores, brain edema, Evans blue (EB) extravasation, and tight junction protein expression were examined at 48 h after MCAO. We also investigated if ADT protected BBB integrity by suppressing post‐ischemic inflammation‐induced Matrix Metalloproteimase‐9 (MMP9) and Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). ADT increased blood H2S concentrations, decreased infarction, and improved neurological deficits. Particularly, ADT reduced EB extravasation, brain edema and preserved expression of tight junction proteins in the ischemic brain. NaHS also increased blood H2S levels and reduced EB extravasation following MCAO. Moreover, ADT inhibited expression of pro‐inflammatory markers induced Nitric Oxide Synthase (iNOS) and IL‐1β while enhanced expression of anti‐inflammatory markers arginase 1 and IL‐10 in the ischemic brain. Accordingly, ADT attenuated ischemia‐induced expression and activity of MMP9. Moreover, ADT reduced NOX‐4 mRNA expression, NOX activity, and inhibited nuclear translocation of Nuclear Factor Kappa‐B (NF‐κB) in the ischemic brain. In conclusion, H2S donors protected BBB integrity following experimental stroke possibly by acting through NF‐κB inhibition to suppress neuroinflammation induction of MMP9 and NOX4‐derived free radicals.

image

To determine H2S effects on blood–brain barrier (BBB) disruption following stroke, we used two structurally unrelated H2S donors ADT and NaHS. Both ADT and NaHS remarkably protected BBB integrity following experimental stroke. The slow‐releasing donor ADT also reduced post‐ischemic inflammation‐induced expression and activity of MMP9 and NOX4 in the ischemic brain possibly by inhibiting NF‐κB activation.
Protecting Mortgage Borrowers through Risk Awareness: Evidence from Variations in State Laws
Authors: COLLINS J. MICHAEL
Published: February 2014

In the wake of historic levels of mortgage defaults, regulators have debated how to regulate certain high‐risk loans because of the risks of foreclosure involved. This study examines state laws that required loan applicants to receive information about the risks of foreclosure before they could sign certain mortgage contracts. Skeptics suggest that disclosures are largely ignored by consumers, yet controlling for other factors this study shows that loan applicants in states with enhanced warnings about foreclosures were more likely to reject high‐cost refinance mortgage loan offers from a lender. Enhanced disclosures with features such as risk warnings, signatures, and referrals to counseling are being implemented as part of Dodd–Frank consumer finance reforms. This study suggests these strategies may be useful to balance consumer protection and access to high‐risk credit.
Vital exhaustion and anxiety are related to subjective quality of life in patients with acute myocardial infarct before cardiac rehabilitation
Authors: Rafael Beatrix , Simon Attila , Drótos Gergely , Balog Piroska
Published: February 2014

Aims and objectives

To examine psychological risk factors and somatic factors in patients after myocardial infarction. To study the relationship between somatic and psychological factors, their influence on subjective quality of life (well‐being) and also to examine possible gender differences.

Background

There has been a growing body of evidence that psychosocial factors are risk factors for incident and recurrent myocardial infarction.

Design

Descriptive correlational and cross‐sectional survey design.

Methods

In patients (n = 97, 67 men), the level of depression and anxiety, vital exhaustion, sleep disturbances and well‐being were assessed. Left ventricular ejection fraction, left ventricular diastolic diameter, body mass index, metabolic equivalents and the number of diseased vessels were retrieved from medical records.

Results

Anxiety, vital exhaustion and sleep disturbances were significantly higher in women than in men. Well‐being showed a significant linear correlation with body mass index, anxiety, depression, vital exhaustion and sleep disturbances scores. After adjustment for psychological risk factors and somatic parameters, only vital exhaustion and anxiety correlated significantly with well‐being. However, there were gender differences in predictive variables of well‐being. Anxiety in men and vital exhaustion in women showed a linear correlation with the subjective quality of life.

Conclusion

Our study revealed that only vital exhaustion and anxiety showed a significant correlation with well‐being in patients.

Relevance to clinical practice

During cardiac rehabilitation, it is important to detect and treat not only depression but also vital exhaustion and anxiety, because by reducing these psychological conditions, we can improve well‐being.
Internal Carotid Artery Floating Thrombus in Relapsing Polychondritis
Authors: Karapanayiotides Theodoros , Kouskouras Konstantinos , Ioannidis Panagiotis , Polychroniadou Eleni , Grigoriadis Nikolaos , Karacostas Dimitrios
Published: February 2014

Relapsing polychondritis is a rare autoimmune disease characterized by inflammation of cartilaginous tissues. It may be associated with systemic and cerebral vasculitis and exceptionally with ischemic stroke. Brain infarction associated with internal carotid artery thrombus, in a setting of relapsing polychondritis, has never been reported. We present a 52‐year‐old man without any known risk factors for stroke, treated with prednisone and azathioprine for relapsing polychondritis, who presented a minor left hemisphere stroke. Ultrasound of the neck vessels revealed an isoechogenic thrombus in the left internal carotid artery superimposed on a smooth moderately stenosing isoechogenic atheroma of the carotid bulb. The patient was treated with high‐dose tinzaparin and was followed with serial ultrasound. After 16 days, the thrombus demonstrated a hypoechogenic core surrounded by a hyperechogenic rim and the following day it resolved completely. Thrombus formation on a small unruptured plaque may reflect involvement by relapsing polychondritis of the intimal proteoglycans that hold a role in the development of atheromatosis.
Ligand‐Based Molecular MRI: O‐17 JJVCPE Amyloid Imaging in Transgenic Mice
Authors: Suzuki Kiyotaka , Igarashi Hironaka , Huber Vincent J. , Kitaura Hiroki , Kwee Ingrid L. , Nakada Tsutomu
Published: February 2014

BACKGROUND

Development of molecular MR imaging (MRI) similar to PET imaging using contrast agents such as gadolinium as probe have been inherently hampered by incompatibility between potential probe (charged molecules) and membrane permeability. Nevertheless, considering the inherent spatial resolution limit for PET of 700μ, the superior microscopic resolution of MRI of 4 μ presents a strong incentive for research into ligand‐based molecular MRI.

METHODS

17O exhibits JJ vicinal coupling with a covalently bound proton in a hydroxyl group. This 17O coupled proton can be ionized in water solution and interexchange with other water protons. This property can be utilized as “probe” in T2‐weighted imaging and developed into ligand‐based molecular MRI. We examined β‐amyloid distribution in human APP overexpressed transgenic mice in vivo following injection of 17O labeled Pittsburg compound B (17O‐PiB).

RESULTS

JJVCPE imaging successfully imaged 17O‐PiB, unequivocally establishing that 17O JJVCPE imaging can be developed into PET‐like molecular MRI in clinical medicine.

CONCLUSIONS

The study represents the first successful ligand‐based molecular MRI in vivo. This is also the first in vivo amyloid imaging using MRI. High‐resolution molecular MRI with high specificity under clinical settings, such as in vivo microscopic imaging of senile plaque, is a foreseeable aim.
The effect of experimental balancing interferences on masticatory performance
Authors: Eberhard L. , Braun S. , Wirth A. , Schindler H.‐J. , Hellmann D. , Giannakopoulos N.N.
Published: February 2014

Immediate adaptation to experimental‐balancing interferences is known to affect jaw kinematics and electromyographic activity (EMG). However, little is known about the influence on masticatory performance parameters. This study hypothesises that balancing‐side interferences significantly reduce the performance of the masticatory system. Twenty‐one healthy subjects (eleven female, mean age: 24·1 ± 1·2 years) chewed standardised silicone cubes performing 15 masticatory cycles on the right side under three experimental conditions: (i) natural dentition (ND), (ii) splints with structured occlusal profiles (SS) (iii) splints with balancing interferences in the left molar region (OI). The particle size distribution was determined by a validated scanning procedure and curve fitted with the Rosin–Rammler function to determine X50‐values. The EMG of both temporalis and masseter muscles was recorded simultaneously, and the total muscle work (TMW) was calculated. A jaw‐tracking device recorded the incisal movement path (IMP). The functional parameters under the experimental conditions were compared by repeated‐measures analysis of variance. The findings confirm our hypothesis. The X50‐values differed significantly (P < 0·01) between ND and OI (4·34 vs. 4·60 mm), and between SS and OI (4·34 vs. 4·60 mm), respectively. In contrast, no significant differences (P > 0·05) were observed between SS and ND. There was no significant difference in both TMW (1269·0 vs. 1284·9 vs. 1193·9 μV*s) and IMP (720·2 vs. 735·3 vs. 723·1 mm) amongst the three conditions (P > 0·05). These findings confirm the assumption that the disturbance of the habitual chewing cycles by balancing‐side interferences significantly reduces the masticatory performance in the short term. Occlusal balancing‐side interferences are common technical failures of dental restorations. Simulation of this condition caused deterioration of masticatory performance in healthy young adults. Further studies should be carried out, on whether the observed effect is long‐term and whether masticatory performance decreases even more in patients with reduced adaptive capacity.
The rate and pattern of urea infusion into the rumen of wethers alters nitrogen balance and plasma ammonia
Authors: Recavarren M. I. , Milano G. D.
Published: February 2014

Changes in N balance, urinary excretion of purine derivative (PD), urea, creatinine and ammonia and plasma ammonia, glucose, urea, insulin and IGF‐1 were examined in four wethers (37 ± 2.6 kg BW). The animals were fitted with permanent ruminal catheters, fed lucerne hay (9.4 MJ/day; 23 g N/day; 7 g soluble N/day, 6 equal meals/day) and treated with contrasting rates of urea infusion into the rumen: first, a continuous infusion (CT), at 3.2 mg urea‐N/min for 10 days and then a discontinuous infusion (DT) at 156 mg urea‐N/min for 4 min; in 6 daily doses with the meals for 7 days. N balance was calculated from pooled samples of faeces and urine. Jugular blood samples were collected before and 1.5 h after the morning meal (M1) on days CT10, DT2, DT4 and DT6. N retention decreased during DT (p = 0.01) due to a significant increase of N excretion in urine (4 g/day; p = 0.009) and faeces (1 g/day; p = 0.02). Dry matter (p < 0.001) and N digestibility in vivo (p = 0.01) decreased significantly during DT. Urinary urea and PD excretion were not altered by treatment. Significant linear (p = 0.004) and quadratic (p = 0.001) effects were observed for plasma ammonia in M1 (from 170 CT10 to 235 μm DT2 and returned to 120 μm DT6). No changes were observed in plasma glucose, urea, insulin and IGF‐1. Results indicate that changes from CT to DT reduced N retention in sheep due to enhanced urinary N excretion, but it was not associated with changes in urinary urea or PD excretion; or plasma concentrations of insulin and IGF‐1. As the dry matter (DM) an N digestibility could account a 0.23 of the decrease in N retention; the largest fraction of the reduction in N retention remained unexplained by the results.
Toward an empirical framework for interpreting plastid evolution
Authors: Stiller John W.
Published: February 2014

The idea that evolutionary models should minimize plastid endosymbioses has dominated thinking about the history of eukaryotic photosynthesis. Although a reasonable starting point, this framework has not gained support from observed patterns of algal and plant evolution, and can be an obstacle to fully understanding the modern distribution of plastids. Empirical data indicate that plastid losses are extremely uncommon, that major changes in plastid biochemistry/architecture are evidence of an endosymbiotic event, and that comparable selection pressures can lead to remarkable convergences in algae with different endosymbiotic origins. Such empirically based generalizations can provide a more realistic philosophical framework for interpreting complex and often contradictory results from phylogenomic investigations of algal evolution.
Molecular and morphological evidence for Sheathia gen. nov. (Batrachospermales, Rhodophyta) and three new species
Authors: Salomaki Eric D. , Kwandrans Janina , Eloranta Pertti , Vis Morgan L.
Published: February 2014

The freshwater red algal genus Batrachospermum has been shown to be paraphyletic since the first molecular studies of the Batrachospermales. Previous research, along with this study, provides strong support for the clade Batrachospermum section Helminthoidea. This study has found that heterocortication, the presence of both cylindrical and bulbous cells on the main axis, is an underlying synapomorphy of this clade. Based on support from DNA sequences of the rbcL gene, the COI barcode region and the rDNA ITS 1 and 2, along with morphological studies, the new genus Sheathia is proposed. Seven heterocorticate species were recognized from the molecular clades. Sheathia boryana and S. exigua sp. nov. appear to be restricted to Europe, whereas S. confusa occurs in Europe and New Zealand. Sheathia involuta is widespread in the USA and reported for the first time from Europe. Sheathia americana sp. nov., has been collected in the USA and Canada, and S. heterocortica and S. grandis sp. nov. have been collected only in the USA. Sheathia confusa and S. grandis can be distinguished based on morphological characters, whereas DNA sequence data are required to conclusively distinguish the other species. Sheathia fluitans and S. carpoinvolucra also are placed within this genus based on the presence of heterocortication. These data also hint at greater diversity among non‐heterocorticate Sheathia than is recognized by the single species name S. arcuata.