6,707 research outputs found
Designing probiotic therapies with broad-spectrum activity against a wildlife pathogen
Host-associated microbes form an important component of immunity that protect
against infection by pathogens. Treating wild individuals with these protective microbes,
known as probiotics, can reduce rates of infection and disease in both wild and captive
settings. However, the utility of probiotics for tackling wildlife disease requires that
they offer consistent protection across the broad genomic variation of the pathogen
that hosts can encounter in natural settings. Here we develop multi-isolate probiotic
consortia with the aim of effecting broad-spectrum inhibition of growth of the lethal
amphibian pathogen Batrachochytrium dendrobatidis (Bd) when tested against nine
Bd isolates from two distinct lineages. Though we achieved strong growth inhibition
between 70 and 100% for seven Bd isolates, two isolates appeared consistently
resistant to inhibition, irrespective of probiotic strategy employed. We found no evidence
that genomic relatedness of the chytrid predicted similarity of inhibition scores, nor that
increasing the genetic diversity of the bacterial consortia could offer stronger inhibition
of pathogen growth, even for the two resistant isolates. Our findings have important
consequences for the application of probiotics to mitigate wildlife diseases in the face of
extensive pathogen genomic variation
Thermodynamic properties of the exactly solvable transverse Ising model on decorated planar lattices
The generalized mapping transformation technique is used to obtain the exact
solution for the transverse Ising model on decorated planar lattices. Within
this scheme, the basic thermodynamic quantities are calculated for different
planar lattices with arbitrary spins of decorating atoms. The particular
attention has been paid to the investigation of the transverse-field effects on
magnetic properties of the system under investigation. The most interesting
numerical results for the phase diagrams, compensation temperatures and several
thermodynamic quantities are discussed in detail for the ferrimagnetic version
of the model.Comment: 9 pages, 13 figures, submitted to Journal of Magnetism and Magnetic
Material
Enumerating Cyclic Orientations of a Graph
Acyclic and cyclic orientations of an undirected graph have been widely
studied for their importance: an orientation is acyclic if it assigns a
direction to each edge so as to obtain a directed acyclic graph (DAG) with the
same vertex set; it is cyclic otherwise. As far as we know, only the
enumeration of acyclic orientations has been addressed in the literature. In
this paper, we pose the problem of efficiently enumerating all the
\emph{cyclic} orientations of an undirected connected graph with vertices
and edges, observing that it cannot be solved using algorithmic techniques
previously employed for enumerating acyclic orientations.We show that the
problem is of independent interest from both combinatorial and algorithmic
points of view, and that each cyclic orientation can be listed with
delay time. Space usage is with an additional setup cost
of time before the enumeration begins, or with a setup cost of
time
Health Behavior Change Interventions for Teenage and Young Adult Cancer Survivors: A Systematic Review
PURPOSE: It is important that teenage and young adult (TYA) cancer survivors adopt a healthy lifestyle, since health vulnerabilities associated with their diagnosis and treatment may be exacerbated by poor health behaviors. This review aims to synthesize the current literature on health behavior change interventions created specifically for TYA-aged cancer survivors. METHOD: MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched for studies investigating interventions targeting one or more health behaviors, including: physical activity, diet, smoking cessation, and alcohol consumption. Studies were eligible for review if the study population were defined as TYA cancer survivors and the mean age of the sample was younger than 30 years of age. RESULTS: Twelve studies were identified, of which nine were randomized controlled trials. Physical activity was the most commonly targeted health behavior. Six of the 12 interventions included within this review were successful in changing health behavior. Due to the heterogeneity of intervention characteristics, the relationship between intervention efficacy or outcome and intervention content, delivery mode, or theoretical framework was not discernible. Nevertheless, trends emerged relating to the delivery and content of health behavior interventions designed specifically for TYA cancer survivors. CONCLUSION: More research is required to identify the most effective means of promoting health behavior change among the TYA cancer survivor population. Specifically, future research should focus on providing evidence of the efficiency and feasibility of interventions that use online technologies to facilitate remote intervention delivery and peer support
A Bayesian method for evaluating and discovering disease loci associations
Background: A genome-wide association study (GWAS) typically involves examining representative SNPs in individuals from some population. A GWAS data set can concern a million SNPs and may soon concern billions. Researchers investigate the association of each SNP individually with a disease, and it is becoming increasingly commonplace to also analyze multi-SNP associations. Techniques for handling so many hypotheses include the Bonferroni correction and recently developed Bayesian methods. These methods can encounter problems. Most importantly, they are not applicable to a complex multi-locus hypothesis which has several competing hypotheses rather than only a null hypothesis. A method that computes the posterior probability of complex hypotheses is a pressing need. Methodology/Findings: We introduce the Bayesian network posterior probability (BNPP) method which addresses the difficulties. The method represents the relationship between a disease and SNPs using a directed acyclic graph (DAG) model, and computes the likelihood of such models using a Bayesian network scoring criterion. The posterior probability of a hypothesis is computed based on the likelihoods of all competing hypotheses. The BNPP can not only be used to evaluate a hypothesis that has previously been discovered or suspected, but also to discover new disease loci associations. The results of experiments using simulated and real data sets are presented. Our results concerning simulated data sets indicate that the BNPP exhibits both better evaluation and discovery performance than does a p-value based method. For the real data sets, previous findings in the literature are confirmed and additional findings are found. Conclusions/Significance: We conclude that the BNPP resolves a pressing problem by providing a way to compute the posterior probability of complex multi-locus hypotheses. A researcher can use the BNPP to determine the expected utility of investigating a hypothesis further. Furthermore, we conclude that the BNPP is a promising method for discovering disease loci associations. © 2011 Jiang et al
Use of a Chirp Waveform in Pulsed Eddy Current Crack Detection
When an electrical conductor containing a surface-breaking crack is subjected to a short pulse of electromagnetic radiation, the reflected field contains transient features related to the depth of the crack. This has been demonstrated in both theoretical calculations [1] and in experiments [2,3] on shallow (0.13 mm to 1.3 mm) slots in a low conductivity titanium alloy. Specifically, these results show that the peak crack signal is delayed in time by an amount proportional to the square of the crack depth, and that the signal decay times also increase with increasing depth
Minimal Intervention Needed for Change: Definition, Use, and Value for Improving Health and Health Research
Much research focuses on producing maximal intervention effects. This has generally not resulted in interventions being rapidly or widely adopted or seen as feasible given resources, time, and expertise constraints in the majority of real-world settings. We present a definition and key characteristics of a minimum intervention needed to produce change (MINC). To illustrate use of a MINC condition, we describe a computer-assisted, interactive minimal intervention, titled Healthy Habits, used in three different controlled studies and its effects. This minimal intervention produced modest to sizable health behavior and psychosocial improvements, depending on the intensity of personal contacts, producing larger effects at longer-term assessments. MINC comparison conditions could help to advance both health care and health research, especially comparative effectiveness research. Policy and funding implications of requiring an intervention to be demonstrated more effective than a simpler, less costly MINC alternative are discussedYe
Protecting eyewitness evidence: Examining the efficacy of a self-administered interview tool
Given the crucial role of eyewitness evidence, statements should be obtained as soon as possible after an incident. This is not always achieved due to demands on police resources. Two studies trace the development of a new tool, the Self-Administered Interview (SAI), designed to elicit a comprehensive initial statement. In Study 1, SAI participants reported more correct details than participants who provided a free recall account, and performed at the same level as participants given a Cognitive Interview. In Study 2, participants viewed a simulated crime and half recorded their statement using the SAI. After a delay of 1 week, all participants completed a free recall test. SAI participants recalled more correct details in the delayed recall task than control participants
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Local costs of conservation exceed those borne by the global majority
Cost data are crucial in conservation planning to identify more efficient and equitable land use options. However, many studies focus on just one cost type and neglect others, particularly those borne locally. We develop, for a high priority conservation area, spatial models of two local costs that arise from protected areas: foregone agricultural opportunities and increased wildlife damage. We then map these across the study area and compare them to the direct costs of reserve management, finding that local costs exceed management costs. Whilst benefits of conservation accrue to the global community, significant costs are borne by those living closest. Where livelihoods depend upon opportunities forgone or diminished by conservation intervention, outcomes are limited. Activities can be displaced (leakage); rules can be broken (intervention does not work); or the intervention forces a shift in livelihood profiles (potentially to the detriment of local peoples’ welfare). These raise concerns for both conservation and development outcomes and timely consideration of local costs is vital in conservation planning tools and processes
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