PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Community assembly”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources

Doctors, patients and the search for the truth on the Internet.

The overnight availability of huge amounts of medical information from the internet has dramatically affected patients and doctors, and has swiftly highlighted a pressing need to deal with the problem of assessing the validity of such information. A number of further issues arise from this, most notably the questionable practice of selling supposed 'miracle cures' via the Internet. The introduction of measures that ensure the regulation of health-related websites has to be a priority for the health care profession. It is important not only to protect patients, and reduce the amount of doctors' time that is wasted, but also to allow confidence to develop in the reputable sites that exist. Such sites can provide accurate and useful information and can help to assemble supportive health-related communities on-line; facets that could be of great benefit to both patients and doctors alike.

Humans↗

Current practice of abdominal fascial closure: a survey of Ontario general surgeons.

OBJECTIVES: To determine the current practice of abdominal fascial closure among provincial general surgeons. The primary objective was to determine the proportion of surgeons choosing absorbable versus nonabsorbable sutures. Secondary objectives included determining knowledge and attitudes of surgeons to evidence-based medicine and concordance of current practice with level I evidence. DESIGN: A survey. SETTING: The province of Ontario. PARTICIPANTS: One hundred general surgeons. METHODS: A stratified random sample of community and academic surgeons was assembled and a questionnaire was mailed to them. Common clinical scenarios and questions pertaining to attitudes and knowledge of evidence-based medicine were included. MAIN OUTCOME MEASURES: Use of absorbable versus nonabsorbable suture material. Willingness to change current practice on evidence-based level I reports. RESULTS: Most surgeons (86%) chose an absorbable suture for abdominal fascial closure. Nonabsorbable suture was chosen by 58% of surgeons in the highly contaminated surgical scenario. Eighty-one percent of surgeons indicated they would be willing to change their current practice of fascial closure if there was evidence that the incidence of wound complications was reduced. Polyglactin (Vicryl) was the most commonly chosen suture. CONCLUSIONS: The current practice of abdominal fascial closure among Ontario general surgeons is in disagreement with the findings from a recent meta-analysis, recommending a nonabsorbable suture for a 32% relative risk reduction in the incisional hernia rate. The majority of surgeons employ a continuous absorbable closure in common surgical scenarios. A definitive randomized controlled trial comparing continuous nonabsorbable closure versus continuous absorbable closure is warranted.

Abdomen↗

The evolution of female mating preferences: differentiation from species with promiscuous males can promote speciation.

Females of many species are frequently courted by promiscuous males of their own and other closely related species. Such mating interactions may impose strong selection on female mating preferences to favor trait values in conspecific males that allow females to discriminate them from their heterospecific rivals. We explore the consequences of such selection in models of the evolution of female mating preferences when females must interact with heterospecific males from which they are completely postreproductively isolated. Specifically, we allow the values of both the most preferred male trait and the tolerance of females for males that deviate from this most preferred trait to evolve. Also, we consider situations in which females base their mating decisions on multiple male traits and must interact with males of multiple species. Females will rapidly differentiate in preference when they sometimes mistake heterospecific males for suitable mates, and the differentiation of female preference will select for conspecific male traits to differentiate as well. In most circumstances, this differentiation continues indefinitely, but slows substantially once females are differentiated enough to make mistakes rare. Populations of females with broader preference functions (i.e., broader tolerance for males with trait values that deviate from females' most preferred values) will evolve further to differentiate if the shape of the function cannot evolve. Also, the magnitude of separation that evolves is larger and achieved faster when conspecific males have lower relative abundance. The direction of differentiation is also very sensitive to initial conditions if females base their mate choices on multiple male traits. We discuss how these selection pressures on female mate choice may lead to speciation by generating differentiation among populations of a progenitor species that experiences different assemblages of heterospecifics. Opportunities for differentiation increase as the number of traits involved in mate choice increase and as the number of species involved increases. We suggest that this mode of speciation may have been particularly prevalent in response to the cycles of climatic change throughout the Quaternary that forced the assembly and disassembly of entire communities on a continentwide basis.

Animals↗

[Risk factors for community acquired pneumonia (CAP). A systematic review].

BACKGROUND AND OBJECTIVE: Community acquired pneumonia (CAP) is the most frequent mortal infectious disease in the western industrial countries. So far no detailed information about incidence, pathogenetic agents, medical service and risk factors existed within Germany. This article reviews international studies, which identified risk factors for CAP. METHOD: The MEDLINE database search comprised 743 articles from 1966 to December 2003. Ten published studies analysing risk factors for CAP were included in this study. RESULTS: Age, gender, smoking and chronic lung diseases ranged among the leading risk factors. Other variables, like medication, dangerous substances, alcohol or sociodemographic factors have so far been insufficiently proved. CONCLUSION: Comparable data concerning CAP in Germany are currently inadequate. In order to improve the data situation, in 2002, the Community Acquired Pneumonia NETwork (CAPNET) was established. CAPNET assembles and soon intends to publish detailed information about incidence and risk factors of Community Acquired Pneumonia.

Adolescent↗

The nested assembly of plant-animal mutualistic networks.

Most studies of plant-animal mutualisms involve a small number of species. There is almost no information on the structural organization of species-rich mutualistic networks despite its potential importance for the maintenance of diversity. Here we analyze 52 mutualistic networks and show that they are highly nested; that is, the more specialist species interact only with proper subsets of those species interacting with the more generalists. This assembly pattern generates highly asymmetrical interactions and organizes the community cohesively around a central core of interactions. Thus, mutualistic networks are neither randomly assembled nor organized in compartments arising from tight, parallel specialization. Furthermore, nestedness increases with the complexity (number of interactions) of the network: for a given number of species, communities with more interactions are significantly more nested. Our results indicate a nonrandom pattern of community organization that may be relevant for our understanding of the organization and persistence of biodiversity.

Animal Population Groups↗

Evaluation of a peri-urban community health worker project in the western Cape.

The South African Christian Leadership Assembly (SACLA) Health Project is a non-governmental organisation that runs a community health worker (CHW) programme in 4 peri-urban townships of Cape Town. A cross-sectional descriptive community survey was conducted in April 1990 to evaluate coverage and health education on oral rehydration solution (ORS) and to plan future preventive, promotive and development programmes. Research concepts and methods were made accessible to the CHWs through a training process designed to facilitate participation in every stage of the research. A multi-stage cluster sampling scheme was used, and the CHWs interviewed 822 residents. Coverage indicators showed that over 80% of all respondents had previously known about or consulted the CHW. The most common community problems related to water, filth and refuse, toilets, housing, unemployment and lack of community facilities. The most common health problems were generalised aches and pains, chest problems, skin problems, worms, and diarrhoea. An index developed to measure knowledge of ORS showed very few respondents had 'complete knowledge'. The community's expectations of the CHW included health education, attending to sanitation problems, providing a clean environment, organising community facilities, and helping with employment.

Community Health Services↗

Accurate phylogenetic classification of variable-length DNA fragments.

Metagenome studies have retrieved vast amounts of sequence data from a variety of environments leading to new discoveries and insights into the uncultured microbial world. Except for very simple communities, the encountered diversity has made fragment assembly and the subsequent analysis a challenging problem. A taxonomic characterization of metagenomic fragments is required for a deeper understanding of shotgun-sequenced microbial communities, but success has mostly been limited to sequences containing phylogenetic marker genes. Here we present PhyloPythia, a composition-based classifier that combines higher-level generic clades from a set of 340 completed genomes with sample-derived population models. Extensive analyses on synthetic and real metagenome data sets showed that PhyloPythia allows the accurate classification of most sequence fragments across all considered taxonomic ranks, even for unknown organisms. The method requires no more than 100 kb of training sequence for the creation of accurate models of sample-specific populations and can assign fragments >or=1 kb with high specificity.

Animals↗

Rapid assessment procedures in environmental sanitation research: a case study from the northern border of Mexico.

BACKGROUND: There is a need to enhance the quality and sustainability of environmental health programs in Mexico. What socio-cultural factors influenced the adoption or rejection of Clean Water in Homes programs in this population? We applied rapid appraisal procedures (RAP) to evaluate these community-based programs. METHOD: Qualitative study conducted in communities along Mexico's northern border. We conducted informal dialogues, semi-structured interviews, field notes and observations. Home visits used a checklist to observe: sources of water, handwashing, as well as human waste and garbage disposal patterns. Data analysis was conducted using ATLAS.ti, which facilitated comparison and illustration of discrepancies, the elaboration of emerging issues and relationships between them. RESULTS: Community members perceived that the Clean Water program was a top-down intervention. Water is perceived as a political issue and a matter of corruption. Inequity also limits solidarity activities involved in environmental sanitation. Migration to the United States of America (US) contributes to community fragmentation, which in turn dilutes communal efforts to improve water and sanitation infrastructure. While targeting women as program "recipients", the Clean Water program did not take gendered spheres of decision-making into account. Community members and authorities discussed the main results in "assemblies", particularly addressing the needs of excluded groups. CONCLUSION: The oversight of not exploring community members' needs and priorities prior to program implementation resulted in interventions that did not address the structural (economic, infrastructure) and socio-cultural barriers faced by community members to undertake the health-promoting behaviour change, and provoked resentment.

Adolescent↗

Using information technology and community-based research to improve the dental health-care system.

It is commonly acknowledged that the United States' health-care system produces some of the finest care in the world for some people but fails to meet the needs of others. The Institute of Medicine (IOM) issued six aims for a redesigned health-care system, that it be: safe, effective, patient-centered, timely, efficient, and equitable. The purpose of this paper is to use an ongoing community-based study to illustrate current problems in the provision of oral health services that could be addressed through information technology. Appropriate use of information technology can assist dental schools and clinics in community-based clinical outcomes research needed to assemble the evidence base for improving oral health care. This conference serves as an important steppingstone to establish a means for information technology to improve the community's oral health.

California↗

Parasite community structure within and across host populations of a marine pelagic fish: how repeatable is it?

The geographical variation in parasite community structure among populations of the same host species remains one of the least understood aspects of parasite community ecology. Why are parasite communities clearly structured in some host populations, and randomly assembled in others? Here, we address this fundamental question using data on the metazoan parasite communities of different host size-classes of four distinct populations of a small pelagic fish, the Argentine anchovy, Engraulis anchoita, from the South West Atlantic. Within each fish sample, fish length was correlated with both the total intensity of parasites and species richness among infracommunities. More importantly, average fish length correlated with mean infracommunity richness and mean total intensity across the fish samples, indicating that the characteristics of parasite assemblages in a fish population are strongly influenced by the size of its fish in relation to those in other populations. Nested subset patterns were observed in about half of the fish samples. This means that the presence or absence of parasite species among fish individuals is often not random; however, no repeatability of nestedness among component communities was observed. Average fish length did not influence directly the likelihood that a parasite assemblage was significantly nested. However, variables influenced by average fish length, namely mean infracommunity richness and mean total intensity, determine the probability that a nested hierarchy will be observed; host size may thus indirectly affect parasite community structure either itself or via its influence on host movement and feeding patterns. To some extent, this apparent link may be due to the sensitivity of nestedness analyses to the proportion of presence in a presence/absence matrix; this in itself is a biological feature of the parasite community, however, which is associated with mean host length.

Animals↗

Effect of manual brush cleaning on biomass and community structure of microfouling film formed on aluminum and titanium surfaces exposed to rapidly flowing seawater.

Metals exposed to rapidly flowing seawater are fouled by microbes that increase heat transfer resistance. In this study, results of biochemical test methods quantitatively relating the biomass and community structure of the microfouling film on aluminum and titanium to heat transfer resistance across the metal surface during three cycles of free fouling and manual brushing showed that cleaning accelerates the rate of fouling measured as the loss of heat transfer efficiency and as microfouling film biomass. The results also showed that the rate of fouling, measured as an increase in heat transfer resistance, is faster on titanium than on aluminum but that the titanium surface is more readily cleaned. In three cycles of free fouling and cleaning with a stiff-bristle nylon brush, the free-fouling communities re-forming on aluminum became enriched in bacteria containing short-branched fatty acids as the cycling progressed. The free-fouling community on titanium revealed an increasingly diverse morphology under scanning electron microscopy that was enriched in a portion of the microeucaryotes. Brushing removed most of the biomass, but left a residual community that was relatively enriched in a portion of the bacterial assembly containing cyclopropane fatty acids on aluminum and in a more diverse community on the titanium surface. The residual communities left after cleaning of titanium revealed an increase in bacteria with short-branched fatty acids and in microeucaryotes as cleaning continued. No significant changes occurred in the residual microbial community structure left on aluminum with cleaning; it was, again, less diverse than that remaining on titanium. The residual communities secreted a twofold-larger amount of extracellular polymer, measured as the ratio of total organic carbon to lipid phosphate, than did the free-fouling community on both surfaces.

Journal Article↗

Grouping and identification of sequence tags (GRIST): bioinformatics tools for the NEIBank database.

NEIBank is a project to develop and organize genomics and bioinformatics resources for the eye. As part of this effort, tools have been developed for bioinformatics analysis and web based display of data from expressed sequence tag (EST) analyses. EST sequences are identified and formed into groups or clusters representing related transcripts from the same gene. This is carried out by a rules-based procedure called GRIST (GRouping and Identification of Sequence Tags) that uses sequence match parameters derived from BLAST programs. Linked procedures are used to eliminate non-mRNA contaminants. All data are assembled in a relational database and assembled for display as web pages with annotations and links to other informatics resources. Genome projects generate huge amounts of data that need to be classified and organized to become easily accessible to the research community. GRIST provides a useful tool for assembling and displaying the results of EST analyses. The NEIBank web site contains a growing set of pages cataloging the known transcriptional repertoire of eye tissues, derived from new NEIBank cDNA libraries and from eye-related data deposited in the dbEST section of GenBank.

Animals↗

Warfarin prescribing in atrial fibrillation: the impact of physician, patient, and hospital characteristics.

PURPOSE: The study investigated the determinants of warfarin use in patients with atrial fibrillation (AF). METHODS: We assembled a retrospective cohort of community-dwelling elderly patients (aged > or = 66 years) with AF using linked administrative databases. We identified the physicians responsible for the ambulatory care of these patients using physician service claims and compared patients who did and did not have an identifiable provider. For those patients with an identifiable provider, we assessed the association between patient, physician, and hospital factors and warfarin use. RESULTS: Our cohort consisted of 140,185 patients, of whom 116,200 (83%) had an identifiable cardiac provider. Patients without a provider were significantly more likely to have comorbid conditions that increase their risk of warfarin-associated bleeding. After adjustment for clinical factors, patients without a provider were significantly less likely to receive warfarin (odds ratio 0.37, 95% confidence interval: 0.36-0.38). Of patients with providers, 50,551 patients (43.5%) received warfarin within 180 days after hospital discharge. Warfarin use was positively associated with AF-associated stroke risk factors (eg, prior stroke, congestive heart failure) and negatively associated with warfarin-associated bleeding risk factors (eg, history of intracerebral hemorrhage). After controlling for patient and hospital factors, patients cared for by noncardiologist physicians with cardiology consultation were more likely to receive warfarin then patients treated in noncollaborative environments. CONCLUSIONS: Warfarin continues to be substantially underprescribed to patients who are at high risk for AF-associated cardioembolic stroke. Our findings highlight the need for targeted quality improvement interventions and suggest preferred models of AF care involving routine collaboration between cardiologists and other physicians.

Aged↗

Synergic impact mechanisms of cover crop residue on Cd and As availability and native organic carbon mineralization in Cd and As co-contaminated paddy soil.

The synergic impacts of cover crop residue on heavy metal and metalloid availability and soil organic carbon (SOC) mineralization in contaminated paddy soil and the underlying microbial mechanism remain unclear. This study investigated the availability of cadmium (Cd) and arsenic (As) and mineralization of native SOC in paddy soil treated with 0, 0.4 %, 0.8 % and 1.2 % of δ13C-labeled cover crop residue (Astragalus sinicus L.) via 90-day incubation experiments, the related functional genes and functional microbial communities were analyzed using metagenomic binning assembly. Cover crop residue with addition rate from 0.4 % to 1.2 % significantly decreased available Cd by 56 %-85 % but increased available As by 39 %-66 % compared to the control treatment. Cover crop residue resulted in a positive priming effect on native SOC mineralization but benefited SOC sequestration. Cover crop residue increased the abundance of genes encoding iron reductase (mtrABC, pilA, omcB), sulfate reductase (sir, fpr), As(V) reductase (ArsC), organic carbon hydrolases, methanogenesis, and methylotrophy. Genomes associated with Chloroflexota and Bacteroidota encoded all these key pathways, and their abundance increased with cover crop residue application. Cover crop residue decreased soil Eh, dissolved crystalline iron oxides, enriched specific microorganisms, including Chloroflexota and Bacteroidota, and then synergistically promoted the decrease in Cd availability and the increase in As availability and native SOC mineralization in the examined paddy soil. These findings provided practical and feasible guidance for achieving both safe production and carbon sequestration in contaminated paddy fields, highlighting the requirement to cautious utilization of cover crop residue in As-contaminated paddy fileds.

Soil Pollutants↗

Widespread horizontal transfer and strong selection enhance microbial adaptation in Antarctic soils.

Terrestrial Antarctica harbors compositionally diverse and functionally distinct microbial life. Yet the eco-evolutionary processes underlying adaptation to Antarctica's polyextreme conditions remain largely unknown. Here, we address how horizontal gene transfer (HGT) and de novo mutations influence microbial adaptation in 16 Antarctic soils using combined short- and long-read datasets. Phylogenetic reconciliation and mobile genetic element analysis of 676 metagenome-assembled genomes show frequent HGT across communities. While transferred genes span diverse functional categories, those involved in energy metabolism are exchanged at higher frequency. Genes for aerotrophy, i.e. the consumption of atmospheric trace gases to provide energy, carbon, and hydration, are among the most frequently disseminated. Approximately a quarter of carbon monoxide dehydrogenases and [NiFe]-hydrogenases are predicted to be horizontally acquired and are often associated with mobile genetic elements. Analysis of polymorphisms suggests widespread purifying selection, particularly for aerotrophy genes, providing further evidence that aerotrophy is critical for microbial survival in Antarctica. Genetic variation in hydrogenases is tightly associated with predicted protein structures, with intense selection acting on critical sites preserving stability and function. Together, these findings show that previously unrecognized eco-evolutionary dynamics shape the composition and function of Antarctic microbial communities, and confirm aerotrophy is a strongly selected and horizontally disseminated trait.

Antarctic Regions↗

Persistent antimicrobial resistance during soil remediation driven by residual heavy metal co-selection.

Remediation of heavy metal-contaminated soil is a global priority, particularly as reclaimed land increasingly intersects with urban development and human exposure. However, the ecological consequences of soil remediation, especially its impact on antimicrobial resistance (AMR) as a global health threat, have remained poorly understood. Here, we combined single-cell Raman-D₂O probing with genome-resolved metagenomics to monitor the dynamics of phenotypic and genotypic resistance to metals and antibiotics during a 120-day remediation of soils with three contamination levels from a lead-zinc smelting site. Although chemical remediation substantially reduced bioavailable metals (by 42%-65%), AMR was not diminished. Instead, both phenotypic activity and gene abundance of metal- and antibiotic-resistant microorganisms increased, resulting in a two- to three-fold increase in AMR-associated health risks. Among 76 metagenome assembled genomes (MAGs) from phenotypic resistance communities, all Cd resistance-associated MAGs harbored multidrug resistance genes, half of which were colocalized with metal resistance determinants, and their prevalence continued to rise with remediation. These findings reveal that although remediation alleviates acute metal toxicity, residual low-concentration bioavailable metals sustain evolutionary selection for resistance, highlighting a disconnect between chemical recovery and biological safety. Moreover, the improved soil nutrient and physiochemical properties of remediated soils further promoted the proliferation of antibiotic-resistant bacteria. This study offers new ecological insights into the unintended consequences of anthropogenic interventions, underscoring the need to integrate biological safety into soil health and safety assessments.

Soil Microbiology↗

Exogean: a framework for annotating protein-coding genes in eukaryotic genomic DNA.

BACKGROUND: Accurate and automatic gene identification in eukaryotic genomic DNA is more than ever of crucial importance to efficiently exploit the large volume of assembled genome sequences available to the community. Automatic methods have always been considered less reliable than human expertise. This is illustrated in the EGASP project, where reference annotations against which all automatic methods are measured are generated by human annotators and experimentally verified. We hypothesized that replicating the accuracy of human annotators in an automatic method could be achieved by formalizing the rules and decisions that they use, in a mathematical formalism. RESULTS: We have developed Exogean, a flexible framework based on directed acyclic colored multigraphs (DACMs) that can represent biological objects (for example, mRNA, ESTs, protein alignments, exons) and relationships between them. Graphs are analyzed to process the information according to rules that replicate those used by human annotators. Simple individual starting objects given as input to Exogean are thus combined and synthesized into complex objects such as protein coding transcripts. CONCLUSION: We show here, in the context of the EGASP project, that Exogean is currently the method that best reproduces protein coding gene annotations from human experts, in terms of identifying at least one exact coding sequence per gene. We discuss current limitations of the method and several avenues for improvement.

Amino Acid Sequence↗