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1.
The method of ecological transects was used for studying plant-species composition in an aged artificial pine stand created on a composite spruce forest on soddy–podzolic soil (underlain by blanket loams) in the broadleaved–spruce forest subzone (Moscow oblast). The change of edificatory tree species was followed by changes in the ecological conditions and, as a consequence, in the species composition, abundance, and cenotic significance of vegetation. Changes in the pattern of restoration of floristic diversity in different soil-geochemical facies of the transect were observed. 相似文献
2.
Frederic Chatigny 《Journal of applied animal welfare science : JAAWS》2013,16(4):400-410
Fish welfare is still a relatively new field. As such, regulations and protocols to ensure fish welfare are currently limited and vary considerably in different jurisdictions. This is in part because of the ongoing controversy as to whether or not fish feel pain. This controversy has persisted for several years, yet veterinarians have been mostly absent from the discussion so far. This essay aims to address this issue. Here, it is argued that while this controversy has its place, it is unlikely to be resolved in the near future. Fish welfare could instead be improved by pursuing more clinically applicable research to increase knowledge of fishes’ behavior and physiology. Such research would assist in learning the optimal environment for their specific needs, as well as compiling some verified indicators of pain in fish. This would then lead to improved studies that could help to determine if and when analgesic drugs can be beneficial in fish, as they are in many other species. 相似文献
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Morrison K Aguiar Prieto P Castro Domínguez A Waltner-Toews D Fitzgibbon J 《EcoHealth》2008,5(3):346-359
Following the collapse of the Cuban economy in the early 1990s, epidemiologists in the Cuban Ministry of Health noticed dramatic
increases in reported outbreaks of ciguatera fish poisoning (CFP) in some coastal communities. This article summarizes the
results of a comparative case study which applied an ecosystem approach to human health to investigate this issue. Situated
learning and complexity theories were used to interpret the results of the investigation. CFP outbreaks are influenced by
a complex set of interactions between ecological and socioeconomic processes. This study found that the level of organization
of the local sports fishing community and the degree of degradation of the local nearshore marine ecosystem appear to be key
factors influencing the diverging levels of CFP outbreaks recorded in the 1990s in the communities studied. 相似文献
4.
Steve M. Heath Dorothy V. M. Bishop Kimberley E. Bloor Gemma L. Boyle Janet Fletcher John H. Hogben Charles A. Wigley Stephanie H. M. Yeong 《PloS one》2014,9(4)
Rationale
Phonological awareness, letter knowledge, oral language (including sentence recall) and rapid automatised naming are acknowledged within-child predictors of literacy development. Separate research has identified family factors including socio-economic status, parents’ level of education and family history. However, both approaches have left unexplained significant amounts of variance in literacy outcomes. This longitudinal study sought to improve prospective classification accuracy for young children at risk of literacy failure by adding two new family measures (parents’ phonological awareness and parents’ perceived self-efficacy), and then combining the within-child and family factors.Method
Pre-literacy skills were measured in 102 four year olds (46 girls and 56 boys) at the beginning of Preschool, and then at the beginning and end of Kindergarten, when rapid automatised naming was also measured. Family factors data were collected at the beginning of Preschool, and children’s literacy outcomes were measured at the end of Year 1 (age 6–7 years).Results
Children from high-risk backgrounds showed poorer literacy outcomes than low-risk students, though three family factors (school socio-economic status, parents’ phonological awareness, and family history) typically accounted for less Year 1 variance than the within-child factors. Combining these family factors with the end of Kindergarten within-child factors provided the most accurate classification (i.e., sensitivity = .85; specificity = .90; overall correct = .88).Implications
Our approach would identify at-risk children for intervention before they began to fail. Moreover, it would be cost-effective because although few at-risk children would be missed, allocation of unnecessary educational resources would be minimised. 相似文献5.
《Journal of receptor and signal transduction research》2013,33(1-4):375-389
AbstractThe heterogeneous environment in which ligand/receptor interactions occur often leads to complex binding behaviour. We consider here the ligand/membrane interaction, emphasizing the possibilities of electrostatic modulation of the overall binding characteristics. The binding of Substance P to neutral or negatively charged planar lipid bilayers was monitored using the capacitance minimization technique. The electrostatic attraction to the charged bilayer potentiates the interaction by more than two orders of magnitude and leads to a nonlinearity in the Scatchard plot of bound vs. bulk concentrations. The Boltzmann accumulation factor, along with the direct measurement of the surface potential, provides an easy explanation of the effect. The general importance of electrostatic accumulation (or repulsion) at surfaces is discussed and the concept applied to examples from the literature. 相似文献
6.
Tamara Shiner Ben Seymour Mkael Symmonds Peter Dayan Kailash P. Bhatia Raymond J. Dolan 《PloS one》2012,7(10)
Background
Bradykinesia is a cardinal feature of Parkinson’s disease (PD). Despite its disabling impact, the precise cause of this symptom remains elusive. Recent thinking suggests that bradykinesia may be more than simply a manifestation of motor slowness, and may in part reflect a specific deficit in the operation of motivational vigour in the striatum. In this paper we test the hypothesis that movement time in PD can be modulated by the specific nature of the motivational salience of possible action-outcomes.Methodology/Principal Findings
We developed a novel movement time paradigm involving winnable rewards and avoidable painful electrical stimuli. The faster the subjects performed an action the more likely they were to win money (in appetitive blocks) or to avoid a painful shock (in aversive blocks). We compared PD patients when OFF dopaminergic medication with controls. Our key finding is that PD patients OFF dopaminergic medication move faster to avoid aversive outcomes (painful electric shocks) than to reap rewarding outcomes (winning money) and, unlike controls, do not speed up in the current trial having failed to win money in the previous one. We also demonstrate that sensitivity to distracting stimuli is valence specific.Conclusions/Significance
We suggest this pattern of results can be explained in terms of low dopamine levels in the Parkinsonian state leading to an insensitivity to appetitive outcomes, and thus an inability to modulate movement speed in the face of rewards. By comparison, sensitivity to aversive stimuli is relatively spared. Our findings point to a rarely described property of bradykinesia in PD, namely its selective regulation by everyday outcomes. 相似文献7.
In behavioral economics, the “endowment effect” describes the robust finding that prices people are willing to accept (WTA) for a good exceed prices people are willing to pay (WTP) for the same good. The increase in WTA values is often explained by the sellers’ negative hedonic response to losing their item. Recent studies, however, show that subtle cues may change participants’ perspective, influencing their valuations. We hypothesized that implicit connotations of instructional language may be one of those cues. To test this hypothesis we manipulated the wording of instructions in two conditions: in the Sell condition, subjects were endowed with a set of pens and asked to select an amount of money for which they would sell the pens back and in the Take condition, subjects were endowed with the pens and asked to select an amount of money they would take for the pens. Participants in each condition also estimated the market value of the pens. Consistent with our hypothesis, WTA in the Sell condition was higher than in the Take condition, though there were no differences in market values between conditions. These findings show that instructional language does influence participant valuations. Furthermore, we suggest that those being asked to “sell” use their market estimations as the salient reference point in the transaction. 相似文献
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Borja Esteve-Altava Jesús Marugán-Lobón Héctor Botella Diego Rasskin-Gutman 《Evolutionary biology》2013,40(2):209-219
Ever since the appearance of the first land vertebrates, the skull has undergone a simplification by loss and fusion of bones in all major groups. This well-documented evolutionary trend is known as “Williston’s Law”. Both loss and fusion of bones are developmental events that generate, at large evolutionary scales, a net reduction in the number of skull bones. We reassess this evolutionary trend by analyzing the patterns of skull organization captured in network models in which nodes represent bones and links represent suture joints. We also evaluate the compensatory process of anisomerism (bone specialization) suggested to occur as a result of this reduction by quantifying the heterogeneity and the ratio of unpaired bones in real skulls. Finally, we perform simulations to test the differential effect of bone losses in skull evolution. We show that the reduction in bone number during evolution is accompanied by a trend toward a more complex organization, rather than toward simplification. Our results indicate that the processes by which bones are lost or fused during development are central to explain the evolution of the morphology of the skull. Our simulations suggest that the evolutionary trend of increasing morphological complexity can be caused as a result of a structural constraint, the systematic loss of less connected bones during development. 相似文献
11.
Prior to coating, tablets are usually stored for a definite period to enable complete strain recovery and prevent subsequent volumetric expansion-related coating defects. In-line coating is defined as the coating of tablets immediately after compaction. In-line coating will be expected to improve manufacturing efficiencies. In this study, the possibility of in-line coating was studied by evaluating the influence of compaction and coating on tablet dimensional changes. The use of tapered dies for compaction was also evaluated. Two types of tablet coaters which presented different coating environments, namely the Supercell™ coater and pan coater, were employed for coating. The extent of tablet dimensional changes was studied in real time using optical laser sensors in a controlled environment. After compaction, tablet dimensional changes were found to be anisotropic. In contrast, coating resulted in isotropic volume expansion in both the axial and radial directions. Pan coating resulted in significantly greater tablet dimensional changes compared to Supercell™ coating. There was no significant difference in dimensional changes of tablets coated in line or after complete viscoelastic strain recovery for Supercell™ coating. However, significantly different dimensional changes were observed for pan coating. The use of tapered dies during compaction was found to result in more rapid viscoelastic strain recovery and also significantly reduced tablet dimensional changes when tablets were immediately coated after compaction using the pan coater. In conclusion, the Supercell™ coater appeared to be more suitable for in-line tablet coating, while tapered dies were beneficial in reducing tablet dimensional changes when the pan coater was employed for in-line coating.KEY WORDS: continuous manufacturing, in-line coating, tablet coating, tapered dies, viscoelastic strain recovery 相似文献
12.
Non-synonymous single nucleotide polymorphisms (nsSNPs) are single base changes leading to a change to the amino acid sequence of the encoded protein. Many of these variants are associated with disease, so nsSNPs have been well studied, with studies looking at the effects of nsSNPs on individual proteins, for example, on stability and enzyme active sites. In recent years, the impact of nsSNPs upon protein–protein interactions has also been investigated, giving a greater insight into the mechanisms by which nsSNPs can lead to disease. 相似文献
13.
Luuk Wieske Esther Witteveen Camiel Verhamme Daniela S. Dettling-Ihnenfeldt Marike van der Schaaf Marcus J. Schultz Ivo N. van Schaik Janneke Horn 《PloS one》2014,9(10)
Introduction
An early diagnosis of Intensive Care Unit–acquired weakness (ICU–AW) using muscle strength assessment is not possible in most critically ill patients. We hypothesized that development of ICU–AW can be predicted reliably two days after ICU admission, using patient characteristics, early available clinical parameters, laboratory results and use of medication as parameters.Methods
Newly admitted ICU patients mechanically ventilated ≥2 days were included in this prospective observational cohort study. Manual muscle strength was measured according to the Medical Research Council (MRC) scale, when patients were awake and attentive. ICU–AW was defined as an average MRC score <4. A prediction model was developed by selecting predictors from an a–priori defined set of candidate predictors, based on known risk factors. Discriminative performance of the prediction model was evaluated, validated internally and compared to the APACHE IV and SOFA score.Results
Of 212 included patients, 103 developed ICU–AW. Highest lactate levels, treatment with any aminoglycoside in the first two days after admission and age were selected as predictors. The area under the receiver operating characteristic curve of the prediction model was 0.71 after internal validation. The new prediction model improved discrimination compared to the APACHE IV and the SOFA score.Conclusion
The new early prediction model for ICU–AW using a set of 3 easily available parameters has fair discriminative performance. This model needs external validation. 相似文献14.
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Graphene, new generation advance material of two dimensional hexagonal lattice having extraordinary optical signatures, is used as coating material to enhance the surface plasmon resonance (SPR) effect of core@shell metal nanospheres. In a core@shell nanosphere, we have chosen metal as a core and graphene monolayer (GML) as a shell. We have analysed optical signature of coated and non-coated nanospheres in terms of extinction efficiency (Q ext) and tunabilty of surface plasmon resonances using electrostatic model, where particle size is much smaller than the wavelength of incident light. We analysed this model over different metals (silver, gold and aluminium) core, coated with different thickness of GML (d?=?0.1 to 0.5 nm). These core@shell nanospheres are embedded in refractive index media of air (n em?=?1), SiO2 (n em?=?1.47) and TiO2 (n em?=?2.79). The Q ext has been calculated by varying both the core radii as well as the GML shell thickness. Graphene-coated metal nanosphere exhibits SPRs that have wide range tunability from 300 to 1500 nm. In the presenting work, we also analysed that extinction efficiency for metal@GML is higher in TiO2 than others. The optimum value of GML shell thickness is 0.4 nm for TiO2, the magnitude of extinction efficiency is maximum for the optimum thickness. The tunability of these plasmonic resonances is highly dependent on the core@shell material, thickness of Graphene shell and surrounding environment while non-coated metal nano-spheres do not show appropriate SPR tunability. 相似文献
16.
A growing body of evidence points towards epigenetic mechanisms being responsible for a wide range of biological phenomena, from the plasticity of plant growth and development to the nutritional control of caste determination in honeybees and the etiology of human disease (e.g., cancer). With the (partial) elucidation of the molecular basis of epigenetic variation and the heritability of certain of these changes, the field of evolutionary epigenetics is flourishing. Despite this, the role of epigenetics in shaping host–pathogen interactions has received comparatively little attention. Yet there is plenty of evidence supporting the implication of epigenetic mechanisms in the modulation of the biological interaction between hosts and pathogens. The phenotypic plasticity of many key parasite life-history traits appears to be under epigenetic control. Moreover, pathogen-induced effects in host phenotype may have transgenerational consequences, and the bases of these changes and their heritability probably have an epigenetic component. The significance of epigenetic modifications may, however, go beyond providing a mechanistic basis for host and pathogen plasticity. Epigenetic epidemiology has recently emerged as a promising area for future research on infectious diseases. In addition, the incorporation of epigenetic inheritance and epigenetic plasticity mechanisms to evolutionary models and empirical studies of host–pathogen interactions will provide new insights into the evolution and coevolution of these associations. Here, we review the evidence available for the role epigenetics on host–pathogen interactions, and the utility and versatility of the epigenetic technologies available that can be cross-applied to host–pathogen studies. We conclude with recommendations and directions for future research on the burgeoning field of epigenetics as applied to host–pathogen interactions. 相似文献
17.
Molecular docking, molecular mechanics, molecular dynamics and relaxation matrix simulation protocols have been extensively used to generate the structural details of ligand-receptor complexes in order to understand the binding interactions between the two entities. Experimental methods like NMR spectroscopy and X-ray crystallography are known to provide structural information about ligand-receptor complexes. In addition, fluorescence spectroscopy, circular dichroism (CD) spectroscopy and molecular docking have also been utilized to decode the phenomenon of the ligand-DNA interactions, with good correlation between experimental and computational results. The DNA binding affinity was demonstrated by analysing fluorescence spectral data. Structural rigidity of DNA upon ligand binding was identified by CD spectroscopy. Docking is carried out using the DNA-Dock program which results in the binding affinity data along with structural information like interatomic distances and H-bonding, etc. The complete structural analyses of various drug-DNA complexes have afforded results that indicate a specific DNA binding pattern of these ligands. It also exhibited that certain structural features of ligands can make a ligand to be AT- or GC-specific. It was also demonstrated that changing specificity from AT base pairs to GC base pairs further improved the DNA topoisomerase inhibiting activity in certain ligands. Thus, a specific molecular recognition signature encrypted in the structure of ligand can be decoded and can be effectively employed in designing more potent antiviral and antitumour agents. 相似文献
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Background
Carbon dioxide (CO2) is a recognized vasodilator of myocardial blood vessels that leads to changes in myocardial oxygenation through the recruitment of the coronary flow reserve. Yet, it is unknown whether changes of carbon dioxide induced by breathing maneuvers can be used to modify coronary blood flow and thus myocardial oxygenation. Oxygenation-sensitive cardiovascular magnetic resonance (CMR) using the blood oxygen level-dependent (BOLD) effect allows for non-invasive monitoring of changes of myocardial tissue oxygenation. We hypothesized that mild hypercapnia induced by long breath-holds leads to changes in myocardial oxygenation that can be detected by oxygenation-sensitive CMR.Methods and Results
In nine anaesthetized and ventilated pigs, 60s breath-holds were induced. Left ventricular myocardial and blood pool oxygenation changes, as monitored by oxygenation-sensitive CMR using a T2*-weighted steady-state-free-precession (SSFP) sequence at 1.5T, were compared to changes of blood gas levels obtained immediately prior to and after the breath-hold. Long breath-holds resulted in an increase of paCO2, accompanied by a decrease of paO2 and pH. There was a significant decrease of blood pressure, while heart rate did not change. A decrease in the left ventricular blood pool oxygenation was observed, which was similar to drop in SaO2. Oxygenation in the myocardial tissue however, was maintained throughout the period. Changes in myocardial oxygenation were strongly correlated with the change in paCO2 during the breath-hold (r = 0.90, p = 0.010).Conclusion
Despite a drop in blood oxygen levels, myocardial oxygenation is maintained throughout long breath-holds and is linearly correlated with the parallel increase of arterial CO2, a known coronary vasodilator. Breathing maneuvers in combination with oxygenation-sensitive CMR may be useful as a diagnostic test for coronary artery function. 相似文献20.
We compared the performances of the candidate loci for moss DNA barcoding and the primers used in amplifying the loci. Primers for three coded loci (matK, rps4 and rbcL a) and four non coded loci (atpB rbcL, atpF H, psbK I and trnH psbA) of the chloroplast genome, one from the mitochondrial genome (nad5), and one from the nucleus genome (ITS2) were evaluated. Seventy four samples representing 14 species belonging to five genera of Trachypodoaceae (or Meteoriaceae) were screened. All primers for matK and a pair of primers for trnH psbA failed. Low successes were encountered with the primers for atpF H and psbK I. The primers for psbK I produced several bands and the PCR products of atpF H were difficult to sequence. The powers of the remaining six loci were compared using the variability, identification success and the resolutions. It was found that ITS2 is the most promising candidate for DNA barcoding for mosses. Among the chloroplast genes, atpB rbcL exhibited the highest resolution. Although trnH psbA is very variable, it is too short to be an ideal barcode alone. Combinations of chloroplast genes were also tried and Ps of both atpB rbcL+trnH psbA and rbcL a++trnH psbA were 64% using NJ method. More additions of loci did not increase the resolution. No barcoding gap exists for all these loci. Phylogenetic analyses were carried out prior to the DNA barcoding evaluation and some taxonomic problems do exist. This study exemplifies the necessity of correct species delimitation and the adoption of both plastid and nuclear loci in plant DNA barcoding. 相似文献