bluuebunny/crossref_metadata_2025 huggingface dataset:
Community stability and selective extinction during Earth’s greatest mass extinction
Authors: Roopnarine Peter D. , Angielczyk Kenneth D.
Published: February 2015

We modelled the resilience and transient dynamics of terrestrial paleocommunities from the Karoo Basin, South Africa, around the Permian-Triassic mass extinction. Using recently refined biostratigraphic data that suggest two pulses of extinction leading up to the Permian-Triassic boundary, we show that during times of low extinction, paleocommunities were no more stable than randomly assembled communities, but they became stable during the mass extinction. Modelled food webs before and after the mass extinction have lower resilience and less stable transient dynamics compared to random food webs lacking in functional structure but of equal species richness. They are, however, more stable than random food webs of equal richness but with randomized functional structure. In contrast, models become increasingly more resilient and have more stable transient dynamics, relative to the random models, as the mass extinction progressed. The increased stability of the community that resulted from the first pulse of extinction was driven by significant selective extinction against small-bodied amniotes, and significantly greater probabilities of survival of large-bodied amniotes. These results point to a positive relationship between evolved patterns of functional diversity and emergent community dynamics, with observed patterns being more stable than alternative possibilities.

Significance

Anthropogenic impacts on modern ecosystems have no precedents in human history. The fossil record does contain episodes of severe biodiversity crises, but incomplete preservation and low temporal resolution make it difficult to equate fossil data to modern ecological processes. We examined terrestrial paleocommunities from Earth’s most severe mass extinction, the Permian-Triassic mass extinction (PTME), and modelled their dynamic stabilities. We show that during times of low extinction, paleocommunities were no more stable than randomly assembled communities, but they became more stable during the mass extinction. Increased stability resulted mostly from selective extinction and survival based on vertebrate body size. Whether modern communities will behave similarly depends on the similarity between human drivers and those of the PTME.
A Hydrodynamic Approach To Cancer
Authors: Pinkowski Alexander , Lilienblum Walter
Published: February 2015

This is the pre-print version of a paper submitted to Technische Mechanik (ISSN 0232-3869)
Quantifying transport in crowded biochemical environments
Authors: Baker Ruth E. , Simpson Matthew J
Published: February 2015

Transport of cells and biochemical molecules often takes place in crowded, heterogeneous environments. As such, it is important we understand how to quantify crowded transport phenomena, and the possibilities of extracting transport coefficients from limited observations. We employ a volume-excluding random walk model on a square lattice where different fractions of lattice sites are filled with inert, immobile obstacles to investigate whether it is possible to estimate parameters associated with transport when crowding is present. By collecting and analysing data obtained on multiple spatial scales we demonstrate that commonly used models of motility within crowded environments can be used to reliably predict our random walk data. However, infeasibly large amounts of data are needed to estimate transport parameters, and quantitative estimates may differ depending on the spatial scale on which they are collected. We also demonstrate that in models of crowded environments there is a relatively large region of the parameter space within which it is difficult to distinguish between the “best fit” parameter values. This suggests commonly used descriptions of transport within crowded systems may not be appropriate, and that we should be careful in choosing models to represent the effects of crowding upon motility within biochemical systems.
Natural Selection Shapes the Mosaic Ancestry of theDrosophilaGenetic Reference Panel and theD. melanogasterReference Genome
Authors: Pool John E.
Published: February 2015

North American populations ofDrosophila melanogasterare thought to derive from both European and African source populations, but despite their importance for genetic research, patterns of admixture along their genomes are essentially undocumented. Here, I infer geographic ancestry along genomes of theDrosophilaGenetic Reference Panel (DGRP) and theD. melanogasterreference genome. Overall, the proportion of African ancestry was estimated to be 20% for the DGRP and 9% for the reference genome. Based on the size of admixture tracts and the approximate timing of admixture, I estimate that the DGRP population underwent roughly 13.9 generations per year. Notably, ancestry levels varied strikingly among genomic regions, with significantly less African introgression on the X chromosome, in regions of high recombination, and at genes involved in specific processes such as circadian rhythm. An important role for natural selection during the admixture process was further supported by a genome-wide signal of ancestry disequilibrium, in that many between-chromosome pairs of loci showed a deficiency of Africa-Europe allele combinations. These results support the hypothesis that admixture between partially genetically isolatedDrosophilapopulations led to natural selection against incompatible genetic variants, and that this process is ongoing. The ancestry blocks inferred here may be relevant for the performance of reference alignment in this species, and may bolster the design and interpretation of many population genetic and association mapping studies.
Discovery and characterization ofAlurepeat sequences via precise local read assembly
Authors: Wildschutte Julia H , Baron Alayna , Diroff Nicolette M , Kidd Jeffrey M
Published: February 2015

Aluinsertions have contributed to >11% of the human genome and ~30–35Alusubfamilies remain actively mobile, yet the characterization of polymorphicAluinsertions from short-read data remains a challenge. We build on existing computational methods to combineAludetection andde novoassembly of WGS data as a means to reconstruct the full sequence of insertion events from Illumina paired end reads. Comparison with published calls obtained using PacBio long-reads indicates a false discovery rate below 5%, at the cost of reduced sensitivity due to the colocation of reference and non-reference repeats. We generate a highly accurate call set of 1,614 completely assembledAluvariants from 53 samples from the Human Genome Diversity Project panel. We utilize the reconstructed alternative insertion haplotypes to genotype 1,010 fully assembled insertions, obtaining >99% agreement with genotypes obtained by PCR. In our assembled sequences, we find evidence of premature insertion mechanisms and observe 5’ truncation in 16% ofAluYa5 andAluYb8 insertions. The sites of truncation coincide with stem-loop structures and SRP9/14 binding sites in theAluRNA, implicating L1 ORF2p pausing in the generation of 5’ truncations. Additionally, we identified variableAluJ andAluS elements that likely arose due to non-retrotransposition mechanisms.
Optimal Haplotype Assembly from High-Throughput Mate-Pair Reads
Authors: Kamath Govinda M , Şaşoğlu Eren , Tse David
Published: February 2015

Humans have $23$ pairs of homologous chromosomes. The homologous pairs are almost identical pairs of chromosomes. For the most part, differences in homologous chromosome occur at certain documented positions called single nucleotide polymorphisms (SNPs).A haplotype of an individual is the pair of sequences of SNPs on the two homologous chromosomes. In this paper, we study the problem of inferring haplotypes of individuals from mate-pair reads of their genome. We give a simple formula for the coverage needed for haplotype assembly, under a generative model. The analysis here leverages connections of this problem with decoding convolutional codes.
Transdermal neuromodulation of noradrenergic activity suppresses psychophysiological and biochemical stress responses in humans
Authors: Tyler William J. , Boasso Alyssa M. , Mortimore Hailey M. , Silva Rhonda S. , Charlesworth Jonathan D. , Marlin Michelle A. , Aebersold Kirsten , Aven Linh , Wetmore Daniel Z. , Pal Sumon K.
Published: February 2015

We engineered a transdermal neuromodulation approach that targets peripheral (cranial and spinal) nerves and utilizes their afferent pathways as signaling conduits to influence brain function. We investigated the effects of this transdermal electrical neurosignaling (TEN) method on sympathetic physiology in human volunteers under different experimental conditions. In all cases, the TEN involved delivering high-frequency pulsed electrical currents to ophthalmic and maxillary divisions of the right trigeminal nerve (V1/V2) and cervical spinal nerve afferents (C2/C3). Under resting conditions when subjects were not challenged or presented with environmental stimuli, TEN significantly suppressed basal sympathetic tone compared to sham as indicated by functional infrared thermography of facial temperatures. In a different experiment conducted under similar resting conditions, subjects treated with TEN reported significantly lower levels of tension and anxiety on the Profile of Mood States scale compared to sham. In a third experiment when subjects were experimentally stressed by a classical fear conditioning paradigm and a series of time-constrained cognitive tasks, TEN produced a significant suppression of heart rate variability, galvanic skin conductance, and salivary α-amylase levels compared to sham. Collectively these observations demonstrate TEN can dampen basal sympathetic tone and attenuate sympathetic activity in response to acute stress induction. Our physiological and biochemical observations are consistent with the hypothesis that TEN modulates noradrenergic signaling to suppress sympathetic activity. We conclude that dampening sympathetic activity in such a manner represents a promising approach to managing daily stress.
Entrepreneurship and innovation
Authors: Maritz Alex , Donovan Jerome
Published: February 2015

Purpose

– The purpose of this paper is to explore the synergies, similarities and differences between entrepreneurship and innovation education and training programs, with the aim of challenging the context of such programs.

Design/methodology/approach

– This study utilises an extensive review of extant literature in the fields of innovation, entrepreneurship and education. The literature, propositions and discussion are intended to provide a bridge between entrepreneurship and innovation education and training programs and seek to address the scientific legitimacy of these education and training disciplines as separate, yet integrated disciplines.

Findings

– Identifies a need to reconsider the diversity and relationship between innovation and entrepreneurship education and training, primarily from contextual, theoretical, measurement, distinctiveness, content, pedagogical and typology points of view. The range of multiple teaching models and learning processes to embrace in various contexts.

Research limitations/implications

– The propositions allow for the combination of teaching initiatives in a theory-driven framework and their applicability to specific entrepreneurship and innovation education and training situations.

Practical implications

– The authors’ contribution identifies the synergies and differences between entrepreneurship education and training programs. The propositions highlight areas of contextualisation and practice-based view application, to adopt specific learning initiatives between constructs.

Originality/value

– The authors address a gap in the literature regarding the delineation of entrepreneurship and innovation education and training, which has thus far remained sparsely addressed in the education and training literature. The authors provide a practice-based view of propositions, developed for future testing.
The impact of gender perceptions and professional values on women’s careers in nursing
Authors: McIntosh Bryan , McQuaid Ronald , Munro Anne
Published: February 2015

Purpose

– This purpose of this paper is to engage two enduring sets of assumptions within nursing: firstly, that woman with children should prioritise the care of children; and secondly, that nursing standards require nurses to put their profession above other priorities. Commitment is linked to full-time working which contrasts sharply with the reality for many women with children who need to work part-time and are not able to change or extend working hours

Design/methodology/approach

– This qualitative research involved the use of 32 in-depth interviews with 32 female registered nurses with children and without children. They were employed in “acute” nursing, aged between 25 and 60 years, and in registered grades “D” to “senior nurse manager”. They worked or had worked on a variety of employment conditions, some, but not all, had taken career breaks. The rationale for exclusively selecting women was based on the need to identify and describe organisational, situational and individual factors related to women and the associations and barriers which affected their careers.

Findings

– In a female-dominated profession, we find the profession resisting attempts to make the profession more accessible to women with young children. The career progression of women with children is inhibited, and this is driven in part by a determination to maintain “traditional” employment practices.

Originality/value

– This paper develops Heilman’s argument that gender perceptions, by both males and females, can be biased against women, and these produce gender inequalities in employment. These findings are relevant across many areas of employment, and they are significant in relation to broadening the debate around equal opportunities for women.
Multimedia Super Corridor, Malaysia
Authors: Yigitcanlar Tan , Sarimin Muna
Published: February 2015

Purpose

– This paper aims to investigate and provide insights on knowledge-based urban development (KBUD) in the context of emerging economies. KBUD has been an effective strategy and an opportunity for emerging economies for catching up with the developed economies.

Design/methodology/approach

– The paper scrutinizes the Multimedia Super Corridor (MSC) of Malaysia by focusing on the planning, development and orchestration of the knowledge corridor.

Findings

– The paper reveals a number of lessons and insights drawn from the development of MSC as the largest manifestation of the KBUD initiative in Malaysia.

Originality/value

– The paper provides lessons and recommendations on the planning, development and management of KBUD for emerging economies that are seeking a prosperous development.
Environmental factors and traits that drive plant litter decomposition do not determine home‐field advantage effects
Authors: Veen G. F. (Ciska) , Sundqvist Maja K. , Wardle David A.
Published: February 2015

The ‘home‐field advantage’ (HFA) hypothesis predicts that plant litter is decomposed faster than expected underneath the plant from which it originates (‘home’) than underneath other plants (‘away’), because decomposer communities are specialized to break down litter from the plants they associate with. However, empirical evidence shows that the occurrence ofHFAis highly variable, and the reasons for this are little understood.

In our study, we progress our understanding by investigating whetherHFAis stronger for more recalcitrant litter types and under colder conditions and how soil properties and plant functional traits affect the magnitude and direction ofHFA.

In subarctic tundra in northernSweden, we set up a reciprocal transplant litter decomposition experiment along an elevational gradient where three highly contrasting vegetation types (heath, meadow andSalix) occur at all elevations, and where temperature decreases strongly with elevation. In this study, we used a litter bag approach where litters from each elevation × vegetation type combination were decomposed in all combinations of elevation × vegetation type. We also measured community‐level plant functional traits, such as leaf and litter nutrient content. We determined soil biotic and abiotic properties, such as microbial biomass and soil nutrient content, in soil cores collected for each elevation × vegetation type combination.

We found that mass loss increased with plant and litter nutrient content and with soil temperature. In contrast, the occurrence ofHFAwas limited in our study system, and its magnitude and direction could not be explained by vegetation type, elevation, plant traits or soil properties, despite these factors serving as powerful drivers of litter mass loss in our study.

We conclude that although vegetation type and climate are major drivers of litter mass loss, they do not emerge as important determinants ofHFA. Therefore, while rapid shifts in plant community composition or temperature due to global change are likely to influence litter mass loss directly by altering environmental conditions, plant trait spectra and litter quality, indirect effects of global change resulting from decoupling of specialist interactions between litter and decomposer communities appear to be of less importance.
Indirect effects of predators control herbivore richness and abundance in a benthic eelgrass (Zostera marina) mesograzer community
Authors: Amundrud Sarah L. , Srivastava Diane S. , O'Connor Mary I.
Published: February 2015

Herbivore communities can be sensitive to changes in predator pressure (top‐down effects) and resource availability (bottom‐up effects) in a wide range of systems. However, it remains unclear whether such top‐down and bottom‐up effects reflect direct impacts of predators and/or resources on herbivores, or are indirect, reflecting altered interactions among herbivore species.

We quantified direct and indirect effects of bottom‐up and top‐down processes on an eelgrass (Zostera marina) herbivore assemblage. In a field experiment, we factorially manipulated water column nutrients (with Osmocote™ slow‐release fertilizer) and predation pressure (with predator exclusion cages) and measured the effects on herbivore abundance, richness and beta diversity. We examined likely mechanisms of community responses by statistically exploring the response of individual herbivore species to trophic manipulations.

Predators increased herbivore richness and total abundance, in both cases through indirect shifts in community composition. Increases in richness occurred through predator suppression of common gammarid amphipod species (Monocorophium acherusicum and Photis brevipes), permitting the inclusion of rarer gammarid species (Aoroides columbiae and Pontogeneia rostrata). Increased total herbivore abundance reflected increased abundance of a caprellid amphipod species (Caprella sp.), concurrent with declines in the abundance of other common species. Furthermore, predators decreased beta diversity by decreasing variability in Caprella sp. abundance among habitat patches.

Osmocote™ fertilization increased nutrient concentrations locally, but nutrients dissipated to background levels within 3 m of the fertilizer. Nutrient addition weakly affected the herbivore assemblage, not affecting richness and increasing total abundance by increasing one herbivore species (Caprella sp.). Nutrient addition did not affect beta diversity.

We demonstrated that assemblage‐level effects of trophic manipulations on community structure are the result of distinct and often indirect responses of herbivore species. These results underscore the importance of understanding herbivore–herbivore interactions in a system commonly subjected to both eutrophication and overfishing.
Discriminative host sanction together with relatedness promote the cooperation in fig/fig wasp mutualism
Authors: Wang Rui‐Wu , Sun Bao‐Fa , Yang Yan
Published: February 2015

Sanctioning or punishing is regarded as one of the most important dynamics in the evolution of cooperation. However, it has not been empirically examined yet whether or not such enforcement selection by sanctioning or punishing and classical theories like kin or reciprocity selection are separate mechanisms contributing to the evolution of cooperation. In addition, it remains largely unclear what factors determine the intensity or effectiveness of sanction.

Here, we show that in the obligate, interspecific cooperation between figs and fig wasps, the hosted figs can discriminatively sanction cheating individuals by decreasing the offspring development ratio. Concurrently, the figs can reward the cooperative pollinators with a higher offspring development ratio. This sanction intensity and effectiveness largely depend on how closely the host and symbiont are related either in terms of reciprocity exchange or genetic similarity as measured by the reciprocal of the foundress number.

Our results imply that in asymmetric systems, symbionts might be forced to evolve to be cooperative or even altruistic through discriminative sanction against the noncooperative symbiont and reward to the cooperative symbiont by the host (i.e. through a game of ‘carrot and stick’).
Effects of persimmon tannin on survival and reproduction of Halyomorpha halys (Hemiptera: Pentatomidae)
Authors: Kim Junheon , Park Chung Gyoo
Published: February 2015

Halyomorpha halys (Hemiptera: Pentatomidae) occurs in sweet persimmon orchards from late July to early September and its damage level is negligible before mid‐July. It rarely appears in persimmon orchards after mid‐September, but is easily found in soybean fields. From the phenological observation of H. halys, it is assumed that seasonal migration of H. halys to sweet persimmon orchards may be related to the content of soluble tannin in sweet persimmon fruits. The feeding preference of H. halys was evaluated on sweet and astringent persimmon fruits, and the effects of persimmon fruits and purified persimmon tannin were tested on the survival of H. halys. Numbers of visiting bugs and feeding spots on the fruits were significantly higher on sweet persimmon than those on astringent persimmon. There was no significant difference in survivorships of H. halys fed sweet persimmon and soybean. However, the number of eggs laid by sweet persimmon fed adult females was significantly lower than those fed soybean. The higher concentration of persimmon tannin caused higher mortality of H. halys. Male and female H. halys fed with 3% persimmon tannin showed the lowest survival. Longevities of male H. halys fed with 0, 0.01, 0.1 and 1% persimmon tannin were 14.9, 12.7, 14.5 and 16.3 days, respectively. However, males fed with 3% tannin lived only 6.4 days. The longevities of female H. halys were similar to those of male (10.1, 14.4, 13.8, 12.0 and 6.1 days for 0, 0.01, 0.1, 1 and 3% tannin concentration, respectively). These results suggest that H. halys invades sweet persimmon orchards during late July and early September when more suitable foods, e.g. soybean, are in short supply and sweet persimmon fruits become suitable for feeding (e.g. lower tannin content).
Personality, negative affect coping, and drinking alone: a structural equation modeling approach to examine correlates of adolescent solitary drinking
Authors: Creswell Kasey G. , Chung Tammy , Wright Aidan G. C. , Clark Duncan B. , Black Jessica J. , Martin Christopher S.
Published: February 2015

Aims

This study examined the personality traits of negative emotionality and constraint and the ability to resist drinking during negative affective states as correlates of solitary drinking in adolescence. We hypothesized that higher levels of negative emotionality and lower levels of constraint would predict solitary drinking and that these relationships would be mediated by the ability to resist drinking in response to negative emotions.

Design

Structural equation modeling was used to fit a path model from the personality traits of negative emotionality and constraint to solitary drinking status through intermediate effects on the ability to resist drinking during negative emotions using cross‐sectional data.

Setting

Clinical and community settings in Pennsylvania, USA.

Participants

The sample included 761 adolescent drinkers (mean age = 17.1).

Measurements

Adolescents completed the Lifetime Drinking History, the Multidimensional Personality Questionnaire, the Constructive Thinking Inventory and the Situational Confidence Questionnaire.

Findings

The path model provided a good fit to the data. The association between trait negative emotionality and solitary drinking was fully mediated by adolescents' ability to resist drinking during negative affective states (b = 0.05, P = 0.01). In contrast, constraint had a direct effect on solitary drinking (odds ratio (OR) = 0.79, b = –0.23, P<0.01), as well as an indirect effect through the ability to resist drinking during negative affective states (b = –0.03, P = 0.02).

Conclusions

The ability to resist drinking while experiencing negative feelings or emotions may be an important underlying mechanism linking trait negative emotionality (a tendency toward depression, anxiety and poor reaction to stress) and constraint (lack of impulsiveness) to adolescent solitary drinking.
Enduring Capitalism: Instability, Precariousness, and Cycles of Change in an Alaskan Salmon Fishery
Authors: Hébert Karen
Published: February 2015

In this article, I examine producers’ interpretations of economic downturn in an Alaskan commercial fishery to shed light on how workers endure ongoing capitalist vicissitudes and how capitalism itself endures. I focus on Alaska's salmon industry, which has weathered many ups and downs. In the early 2000s, despite strong wild salmon populations, the industry struggled as salmon prices sank to new lows. Drawing on ethnographic research in Bristol Bay, where most residents identify as Alaska Native, I show how salmon producers withstood volatile economic cycles by looking to ecological cycles, particularly the region's salmon returns, to interpret the fluctuations of capitalism and envision a future both within and beyond it. While fishers expressed senses of precariousness during the downturn through metaphors of extinction, they also undertook efforts to “reinvent” the industry, identifying in salmon cycles their own capacity to continue. Highlighting how dramatic ecological fluxes tune Bristol Bay producers to recurring change, I argue that this case reveals a more general pattern by which workers become oriented to ongoing instability. As they draw on experiences forged beyond the terms of capitalism to engage within it, their responses help maintain its cycles but also bolster their ability to persist in its midst. [crisis, capitalism, natural resources, fishing, Alaska]
SELF‐REGULATION SYSTEMS FOR NPO COORDINATION: STRENGTHS AND WEAKNESSES OF LABEL AND UMBRELLA MECHANISMS
Authors: SIMILON Astrid
Published: February 2015

The rise of the non‐profit sector and the increasing competition for funds among its members has increased the need for more transparency, accountability and coordination in fundraising activities. In some countries, self‐regulation has appeared to be the most effective way of meeting these demands and two types of systems have emerged: the labels and the umbrella organizations. This paper analyses their emergence as well as their functioning through four cases studies and highlights their strengths and weaknesses. It shows that despite its willingness, there still remain some gaps that might prevent this sector from achieving those goals.
MATCHING PROFIT AND NON‐PROFIT NEEDS: HOW NPOs AND COOPERATIVES CONTRIBUTE TO GROWTH IN TIME OF CRISIS. A QUANTITATIVE APPROACH
Authors: VIGANÒ Federica , SALUSTRI Andrea
Published: February 2015

We propose a microeconomic model aimed at describing, in a dual production process, the interaction between the formal and the informal sector. The adopted framework is characterized by the absence of information asymmetries. The latter assumption is motivated by the focus of the paper, which chooses a cooperative rather than a competitive interaction between the for‐profit and not for profit sectors, as the non‐profit sector offers services which enable and increase the labour productivity of the workers employed in the for profit sector. Specifically, the non‐profit industry can lower the monetary costs of labour by paying a share of wages and dividends in real terms. As a result, at aggregate level, consumption expenditure decreases proportionally to the share of goods and services that are not bought on the market. In this scenario the non‐profit sector can play an important role in elaborating a way out of the crisis, by: i) reducing the income inequality between the employed and the unemployed, ii) lowering labour costs, and iii) endowing workers with an alternative source of employment. The theoretical analysis, complemented by empirical evidence built on Italian data collected for the period 2005–2012, shows that the model is not yet applicable in the Italian context as the non‐profit industry is growing, but it is still inadequate in size to complement the activities of the for profit sector. However, we claim that Italy should elaborate a way out of the crisis by empowering the Third Sector, and, more in general, a ‘good informal economy’ made of non‐profit institutions.
Effect of water extract from spent mushroom substrate after Ganoderma balabacense cultivation by using JUNCAO technique on production performance and hematology parameters of dairy cows
Authors: Liu Yanling , Zhao Chao , Lin Dongmei , Lin Hui , Lin Zhanxi
Published: February 2015

The spent mushroom substrate of Ganoderma balabacense cultivation (SMSGB) contains a large amount of bioactive substances. However, the potentials of SMSGB for improving milk production in dairy cows have not been thoroughly studied. In this study, the effects of hot water extract (HWE) from spent mushroom substrate after G. balabacense cultivated with JUNCAO, the herbaceous plants long‐known to be suitable for cultivating edible and medicinal fungi, on production performance and hematology parameters of dairy cows, were determined. Holstein dairy cows were fed different doses of HWE. After a 60‐day administration period with 100 g/day of HWE, milk yield, milk protein and triglyceride (TG) levels increased by 4.02% (P < 0.01), 4.49% (P < 0.05) and 32.65% (P < 0.05), respectively; somatic cell count (SCC) and alanine aminotransferase (ALT) were significantly decreased (P < 0.05). The production performance of dairy cows suggests that HWE with SMSGB treatment is effective in improving milk yield (P < 0.01) and hematology parameters of dairy cows, and may be useful as a functional feed additive.
Pharmacological modulation of autophagy to protect cardiomyocytes according to the time windows of ischaemia/reperfusion
Authors: Xu Qiulin , Li Xixian , Lu Yongkang , Shen Liang , Zhang Jingwen , Cao Shiping , Huang Xiaobo , Bin Jianping , Liao Yulin
Published: February 2015

Background and Purpose

Targeted modulation of autophagy induced by myocardial ischaemia/reperfusion has been the subject of intensive investigation, but it is debatable whether autophagy is beneficial or harmful. Hence, we evaluated the effects of pharmacological manipulation of autophagy on the survival of cardiomyocytes in different time windows of ischaemia/reperfusion.

Experimental Approach

We examined the autophagy and apoptosis in cardiomyocytes subjected to different durations of anoxia/re‐oxygenation or ischaemia/reperfusion, and evaluated the effects of the autophagic enhancer rapamycin and inhibitor wortmannin on cell survival.

Key Results

In neonatal rat cardiomyocytes (NRCs) or murine hearts, autophagy was increased in response to anoxia/reoxygenation or ischaemia/reperfusion in a time‐dependent manner. Rapamycin‐enhanced autophagy in NRCs led to higher cell viability and less apoptosis when anoxia was sustained for ≦6 h. When anoxia was prolonged to 12 h, rapamycin did not increase cell viability, induced less apoptosis and more autophagic cell death. When anoxia was prolonged to 24 h, rapamycin increased autophagic cell death, while wortmannin reduced autophagic cell death and apoptosis. Similar results were obtained in mice subjected to ischaemia/reperfusion. Rapamycin inhibited the opening of mitochondrial transition pore in NRCs exposed to 6 h anoxia/4 h re‐oxygenation but did not exert any effect when anoxia was extended to 24 h. Similarly, rapamycin reduced the myocardial expression of Bax in mice subjected to short‐time ischaemia, but this effect disappeared when ischaemia was extended to 24 h.

Conclusions and Implications

The cardioprotection of autophagy is context‐dependent and therapies involving the modification of autophagy should be determined according to the duration of ischaemia/reperfusion.
Radiographic evaluation of immediately loaded implants supporting 2–3 units fixed bridges in the posterior maxilla: a 3‐year follow‐up prospective randomized controlled multicenter clinical study
Authors: Cesaretti Gianfranco , Botticelli Daniele , Renzi Antonio , Rossi Marcello , Rossi Riccardo , Lang Niklaus P.
Published: February 2015

Objective

To compare the survival rate and alveolar bone levels at implants installed in healed sites and functionally loaded within 1 h from installation or after 3 months.

Material and methods

A total of 30 patients (17 male and 13 female) were recruited and 71 implants with a SLA® surface, 4.1 mm in diameter and 8–12 mm long, were installed in a fully healed alveolar ridge, 36 as test and 35 as control implants. The test implants were immediately loaded with a temporary reconstruction in proper occlusion, while the randomly selected control sites received the final reconstruction after 3 months. Radiographic bone levels were determined after implant installation, prosthesis delivery, and at annual intervals thereafter.

Results

One patient of the control and one patient of the test were excluded from evaluation. No further losses of implants or patients were seen up to the 3‐year follow‐up. Hence, data from 28 patients were accounted for. A total of 37 and 36 metal–ceramic crowns were provided at the test and control sites, respectively. No biological and technical complications were observed during the 3‐year follow‐up. Bone levels at the time of implant installation were at 1.6 ± 0.8 and 1.7 ± 0.9 mm from the implant shoulder at the test and control sites, respectively. At prosthesis delivery, the bone levels were located at 2.4 ± 0.7 mm at the control sites 3 months after implant placement. After 1 year of function, similar bone levels were observed at both sites, displaying 2.4 ± 1.0 and 2.5 ± 0.8 mm at the test and control sites, respectively. No differences were found in the subsequent observation periods.

Conclusion

Survival rates and radiographic bone levels after 1, 2, and 3 years of observation did not differ between conventionally installed implants loaded immediately or delayed (after 3 months). Moreover, insertion torque values did not affect osseointegration.
Retracted: Histological and histomorphometric analyses of narrow implants, crestal and subcrestally placed in severe alveolar atrophy: a study in foxhound dogs
Authors: Calvo‐Guirado Josè Luis , Delgado Ruiz Rafael Arcesio , Ramírez‐Fernández Maria Piedad , Abboud Marcus , Janjic Bojan , Maté Sánchez de Val Jose Eduardo
Published: February 2015

Background

Narrow‐diameter implants provide an alternative to the horizontal augmentation techniques situations severe bone atrophy. Lack of bone width and interdental space has been regarded as an encumbrance in the case selection for prosthetic rehabilitation using dental implants.

Objective

The aim of the study was to evaluate bone‐to‐implant contact and marginal bone loss of two different narrow implants in resorbed ridges at different crestal positions.

Material and methods

48 Bredent Narrow® implants (24 MiniSky® and NarowSky®) were placed at crestal and subcrestal levels in healing bone of atrophic alveolar ridge of 6 American foxhounds. Histological and histomorphometric analyses of osseointegration were carried out at 4 and 8 weeks.

Results

Modeling in the marginal defect region was accompanied by marked decreases in the dimensions of both the buccal and the more lingual bone walls. Relative to BIC, significant differences were found in favor of subcrestal group, for both Narrow Sky and MiniSky. Linear measurements showed to be slightly high in the crestal group. With significant differences for PM‐IS (peri‐implant mucosa to implant shoulder) and IS‐BC (implant shoulder to buccal bone crest).

Conclusions

Within the limitations of animal study, it can be stated that the NarrowSky(test group) crestal and subcrestal implants showed less crestal bone resorption, higher ISQ values and most BIC at 4 and 8 weeks of evaluation compared with MiniSky implants (control group). The design of the implants plays an important role in peri‐implant mucosa and crestal bone maintenance at 8‐week follow‐up period.
IFI27, a novel epidermal growth factor‐stabilized protein, is functionally involved in proliferation and cell cycling of human epidermal keratinocytes
Authors: Hsieh W.‐L. , Huang Y.‐H. , Wang T.‐M. , Ming Y.‐C. , Tsai C.‐N. , Pang J.‐H. S.
Published: February 2015

Objectives

IFI27 is highly expressed in psoriatic lesions but its function has not been known. The present study aimed to explore its role in proliferation of epidermal keratinocytes.

Materials and methods

IFI27 knockdown and over‐expression in keratinocytes were used to compare their proliferation, by MTT assay, apoptosis (by annexin V binding) and cell cycle progression by flow cytometry. Formation of cyclin A/CDK1 complex was examined by a co‐immunoprecipitaion method. Anti‐proliferation effects of IFI27 were also examined in vivo by topical application of IFI27 siRNA on imiquimod‐induced psoriatic lesions, in a mouse model.

Results

Epidermal growth factor was demonstrated to increase IFI27 expression by prolonging half‐life of IFI27 protein. The IFI27 knockdown in keratinocytes reduced the proliferation rate, but had no effect on apoptosis nor on apoptosis‐related genes. Interestingly, IFI27 knockdown resulted in S‐phase arrest that was found to be associated with increased Tyr15 phosphorylation of CDK1, reduced CDC25B and reduced formation of cyclin A/CDK1 complex. In addition, IFI27 knockdown was also shown to activate p53 by Ser15 phosphorylation and increase p21 expression. Topical application of IFI27 siRNA on imiquimod‐induced psoriatic lesion in a mouse model reduced epidermal thickness, formation of rete ridges and PCNA expression.

Conclusions

Our study demonstrates for the first time, that cell function of IFI27 is involved in proliferation of skin keratinocytes both in vitro and in vivo. It suggests that IFI27 might be a suitable target for development of a novel anti‐psoriasis therapy.
Parental socioeconomic status and the neural basis of arithmetic: differential relations to verbal and visuo‐spatial representations
Authors: Demir Özlem Ece , Prado Jérôme , Booth James R.
Published: February 2015

We examined the relation of parental socioeconomic status (SES) to the neural bases of subtraction in school‐age children (9‐ to 12‐year‐olds). We independently localized brain regions subserving verbal versus visuo‐spatial representations to determine whether the parental SES‐related differences in children's reliance on these neural representations vary as a function of math skill. At higher SES levels, higher skill was associated with greater recruitment of the left temporal cortex, identified by the verbal localizer. At lower SES levels, higher skill was associated with greater recruitment of right parietal cortex, identified by the visuo‐spatial localizer. This suggests that depending on parental SES, children engage different neural systems to solve subtraction problems. Furthermore, SES was related to the activation in the left temporal and frontal cortex during the independent verbal localizer task, but it was not related to activation during the independent visuo‐spatial localizer task. Differences in activation during the verbal localizer task in turn were related to differences in activation during the subtraction task in right parietal cortex. The relation was stronger at lower SES levels. This result suggests that SES‐related differences in the visuo‐spatial regions during subtraction might be based in SES‐related verbal differences.
Growth, development, and behaviour of the parasitised and unparasitised larvae of a shelter‐building moth and consequences for the resulting koinobiont parasitoid
Authors: Morse Douglass H. , Chapman Grant H.
Published: February 2015

Most attention to size‐time trade‐offs of insects has focused on herbivore risk, with considerably less attention paid to parasitoids. Here, we focus on parasitoid risk, comparing the fates of unparasitised herbivore hosts and parasitised hosts that protect the parasitoids. Success of a koinobiont parasitoid (host grows after parasitisation) depends on maintaining a delicate balance with its host, thereby ensuring its own survival while the host grows. To evaluate growth rate–mortality rate relationships of host and parasitoid, we compared several aspects of the growth, phenology, and behaviour of unparasitised fern moth [Herpetogramma theseusalis (Walker) (Lepidoptera: Crambidae)] larvae and larvae parasitised by Alabagrus texanus (Cresson) (Hymenoptera: Braconidae), a solitary koinobiont (one parasitoid per host) wasp. Host larvae feed and construct shelters on sensitive fern, Onoclea sensibilis L. (Dryopteridaceae). Alabagrus texanus parasitise early‐instar moths in late summer, which overwinter in their host, emerging in mid‐summer to pupate and eclose. During the autumn following hatching and the immediately following spring, parasitised and unparasitised moth larvae did not differ in size, took similar time to choose between satisfactory and unsatisfactory foods, and built similar shelters. Prior to any other changes noted, more parasitised than unparasitised larvae also died when severely starved. Parasitised larvae subsequently grew less and pupated later than unparasitised ones (small size, slow growth), but consumed similar amounts of food. Although the numerically dominant parasitoid of fern moths, we concluded that A. texanus do not efficiently exploit their hosts.
Metapopulation analysis indicates native and non‐native fishes respond differently to effects of wildfire on desert streams
Authors: Whitney James E. , Gido Keith B. , Pilger Tyler J. , Propst David L. , Turner Thomas F.
Published: February 2015

Ash flows and flooding associated with wildfires represent important but understudied sources of disturbance for fish populations. Knowledge concerning these disturbances is especially limited for larger streams where warm water species dominate. Fire‐related disturbances have been hypothesised to differentially affect native and non‐native fishes, although this hypothesis has only been tested for salmonids. The objective of our research was to contrast effects of uncharacteristically large wildfires followed by flooding on metapopulations of native and non‐native fishes in theGilaRiver of southwestNewMexico. Probabilities of occupancy, colonisation and local extinction of fishes were calculated across sites before and during disturbance and were also measured across a broader spatial scale during disturbance to identify potential refuge locations. Occupancy was higher for native fishes than non‐natives, but multiple wildfire and flood events increased extinction probabilities of native species. Responses of non‐native species to wildfires were mixed; extinction of non‐native salmonids increased during disturbance, while extinction of several warm water species remained unchanged or decreased. Several undisturbed sites were poor refugia for natives as they were impacted by non‐native piscivores, dewatering, and fragmentation. However, despite exposure to multiple disturbances, sites located in large tributary and valley reaches were consistently occupied by native species, suggesting these habitats provided refugia. We suggest that management actions (forest thinning; prescribed burning) that restore a more natural disturbance regime of small and less severe fires coupled with habitat remediation activities (non‐native removal; decreased water withdrawal; improved connectivity) might diminish extinction risk for native fishes exposed to wildfire disturbance.
Prevalence of indirect toxicity effects of aluminium flakes on a shredder‐fungal‐leaf decomposition system
Authors: Pacioglu Octavian , Cornut Julien , Gessner Mark O. , Kasprzak Peter
Published: February 2015

Polyaluminium chloride (PAC) addition has been proposed as a technique to precipitate dissolved phosphorus (P) and reduce the internal loading of P in eutrophic hardwater lakes. However, the direct and indirect detrimental effects of PAC on aquatic communities and ecosystem processes are virtually unknown.

We determined how PAC may affect a leaf litter–fungus–shredder decomposition system in the littoral habitat of eutrophic hardwater lakes.We hypothesised that PAC will exert little direct toxicity on aquatic organisms at high pH but trigger indirect bottom‐up effects by affecting fungal biomass, leaf litter food quality (Al, N and P contents), trophic transfer and the behaviour and performance of a leaf‐shredding consumer.

We tested these hypotheses in a microcosm experiment involving a leaf‐shredding amphipod, Gammarus pulex, offered conditioned aspen leaves as food. We measured concentrations of Al, N, P and organic C in water, leaves and gammarids; fungal biomass associated with leaf litter; gammarid survival, body mass, feeding rate (FR) and N assimilation efficiency; and fine‐particulate organic matter (FPOM) generation in microcosms receiving 0, 2 and 20 g Al flakes per m2.

Survival rates of G. pulex were similar in all microcosms, suggesting that even the high dose of Al flakes was below lethal levels. However, exposure to Al flakes decreased fungal biomass in leaves, the FR of gammarids, FPOM production and N assimilation efficiency. The C/N and C/P ratios of both leaves and gammarids also decreased in microcosms receiving Al flakes, supporting the hypothesis that stoichiometric imbalances between food and consumers were altered by exposure to Al flakes.

These results point to the importance of indirect effects of PAC on lake communities and ecosystems beyond direct toxicity on invertebrates. Although not all those effects are necessarily undesirable, their numbers, interdependencies and potential to act in concert suggest they need to be considered in ecotoxicological assessments.