Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Information Distribution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 613 records · Page 34Linked to original sources
PubMed2006

Bayesian synthesis of epidemiological evidence with different combinations of exposure groups: application to a gene-gene-environment interaction.

Meta-analysis to investigate the joint effect of multiple factors in the aetiology of a disease is of increasing importance in epidemiology. This task is often challenging in practice, because studies typically concentrate on studying the effect of only one exposure, sometimes may report the interaction between two exposures, but rarely address more complex interactions that involve more than two exposures. In this paper, we develop a meta-analysis framework that combines estimates from studies of multiple exposures. A key development is an approach to combining results from studies that report information on any subset or combination of the full set of exposures. The model requires assumptions to be made about the prevalence of the specific exposures. We discuss several possible model specifications and prior distributions, including information internal and external to the meta-analysis data set, and using fixed-effect and random-effects meta-analysis assumptions. The methodology is implemented in an original meta-analysis of studies relating the risk of bladder cancer to two N-acetyltransferase genes, NAT1 and NAT2, and smoking status.

Arylamine N-Acetyltransferase↗
PubMed2003

Geographic distribution and morphometric differentiation of Triatoma nitida usinger 1939 (Hemiptera: Reduviidae: Triatominae) in Guatemala.

Triatoma nitida was found in 14 (0.4%) out of 3,726 houses located in six departments across Guatemala, which were surveyed from 1994 to 1998 by the man-hour collection method. Compared to previous information, the distribution of T. nitida in Guatemala has increased from five to nine departments; the species is present in mild climates at altitudes from 960 to 1,500 m. Fourteen percent of the intradomestic T. nitida were infected with Trypanosoma cruzi. The species was often found in conjunction with other triatomines (T. dimidiata and Rhodnius prolixus). The domestic and peridomestic presence of T. nitida in Guatemala was rare, but occasionally this species was colonizing human-made constructions. T. nitida appears to have a low importance as Chagas disease vector in Guatemala, as indicated by its scarce presence in the domestic habitats and defecation patterns. However, it clearly has potential to become a Chagas vector so we recommend an on-going study of the intradomestic presence of T. nitida following the control programs in Guatemala. Morphometric analysis of 47 T. nitida males from three localities showed quantitative differences between the populations, which indicates that geographic distance is an important factor in the structuring of T. nitida populations.

Animals↗
PubMed2002

Mapping of the B1 field distribution of a surface coil resonator using EPR imaging.

Surface coil resonators have been widely used to perform topical EPR spectroscopy. They are usually positioned adjacent to or implanted within the body. For EPR applications these resonators have a number of important advantages over other resonator designs due to their ease of sample accessibility, mechanical fabrication, implementation of electronic tuning and coupling functions, and low susceptibility to sample motions. However, a disadvantage is their B(1) field inhomogeneity, which limits their usefulness for 3D imaging applications. We show that this problem can be addressed by mapping and correcting the B(1) field distribution. We report the use of EPR imaging (EPRI) to map the B(1) distribution of a surface coil resonator. We show that EPRI provides a fast, accurate, and reliable technique to evaluate the B(1) distribution. 3D EPRI was performed on phantoms, prepared using three different saline concentrations, to obtain the B(1) distribution. The information obtained from the phantoms was used to correct the images of living animals. With the use of this B(1) correction technique, surface coil resonators can be applied to perform 3D mapping of the distribution of free radicals in biological samples and living systems.

Animals↗
PubMed1999

Distribution of spatial and nonspatial information in dorsal hippocampus.

The hippocampus in the mammalian brain is required for the encoding of current and the retention of past experience. Previous studies have shown that the hippocampus contains neurons that encode information required to perform spatial and nonspatial short-term memory tasks. A more detailed understanding of the functional anatomy of the hippocampus would provide important insight into how such encoding occurs. Here we show that hippocampal neurons in the rat are distributed anatomically in distinct segments along the length of the hippocampus. Each longitudinal segment contains clusters of neurons that become active when the animal performs a task with spatial attributes. Within these same segments are ordered arrangements of neurons that encode the nonspatial aspects of the task appropriate to those spatial features. Thus, anatomical segregation of spatial information, together with the interleaved representation of nonspatial information, represents a structural framework that may help to resolve conflicting views of hippocampal function.

Animals↗
PubMed2000

Analysis of a distributed neural system involved in spatial information, novelty, and memory processing.

Perceiving a complex visual scene and encoding it into memory involves a hierarchical distributed network of brain regions, most notably the hippocampus (HIPP), parahippocampal gyrus (PHG), lingual gyrus (LNG), and inferior frontal gyrus (IFG). Lesion and imaging studies in humans have suggested that these regions are involved in spatial information processing as well as novelty and memory encoding; however, the relative contributions of these regions of interest (ROIs) are poorly understood. This study investigated regional dissociations in spatial information and novelty processing in the context of memory encoding using a 2 x 2 factorial design with factors Novelty (novel vs. repeated) and Stimulus (viewing scenes with rich vs. poor spatial information). Greater activation was observed in the right than left hemisphere; however, hemispheric effects did not differ across regions, novelty, or stimulus type. Significant novelty effects were observed in all four regions. A significant ROI x Stimulus interaction was observed - spatial information processing effects were largest effects in the LNG, significant in the PHG and HIPP and nonsignificant in the IFG. Novelty processing was stimulus dependent in the LNG and stimulus independent in the PHG, HIPP, and IFG. Analysis of the profile of Novelty x Stimulus interaction across ROIs provided evidence for a hierarchical independence in novelty processing characterized by increased dissociation from spatial information processing. Despite these differences in spatial information processing, memory performance for novel scenes with rich and poor spatial information was not significantly different. Memory performance was inversely correlated with right IFG activation, suggesting the involvement of this region in strategically flawed encoding effort. Stepwise regression analysis revealed that memory encoding accounted for only a small fraction of the variance (< 16%) in medial temporal lobe activation. The implications of these results for spatial information, novelty, and memory processing in each stage of the distributed network are discussed.

Adolescent↗
PubMed2000

Novel immunodeficiency data servers.

The Internet contains scientific information in increasing amounts. It is possible to obtain the latest information, and Web services can easily be maintained and updated. We have set up three Internet services on immunodeficiencies. Immunodeficiency-related mutation infor mation is available in immunodeficiency mutation databases (IDbases). Currently 14 registries are distributed, including information about Bloom syndrome (BLMbase), X-linked agammaglobulinemia (BTKbase), X-linked and autosomal recessive chronic granulomatous diseases (CYBBbase for X-linked CGD, CYBAbase for p22(phox) deficiency, NCF1base for p47(phox) deficiency, NCF2base for p67(phox) deficiency), CD3gamma and CD3epsilon deficiencies (CD3Gbase, CD3Ebase), X-linked hyper-IgM syndrome (CD40Lbase), T-B+ severe combined immunodeficiency (JAK3base), V(D)J recombination defects (RAG1base, RAG2base), X-linked lymphoproliferative syndrome (SH2D1Abase), and ZAP-70 deficiency (ZAP70base). Information on laboratories analysing the genetic defects is collected to IDdiagnostics registry. Due to the rareness of immunodeficiencies there are very few laboratories performing genetic diagnostics. Such laboratories are listed in IDdiagnostics and physicians can use the registry to find a suitable laboratory for their diagnostic needs. Immunodeficiency Resource (IDR) is a comprehensive integrated knowledge base for all the information on immunode ficiencies, including clinical, biochemical, genetic, structural and computational data and analyses. All three services are available at http: //www.uta.fi/imt/bioinfo/.

Artificial Intelligence↗
PubMed1986

[Optico-structural machine analysis of the nuclear chromatin and cytoplasmic SH-groups of epitheliocytes of the oral mucosa of healthy subjects and in peptic ulcer of the stomach and duodenum].

By means of optico-structural machine analysis, epitheliocytes of mucous membrane of the oral walls have been studied in 21 healthy persons and in 30 persons suffering from ulcerous disease of the stomach and duodenum. Changes in densitometric parameters of epitheliocytic nuclei at the ulcerous disease demonstrate increasing amount of heterochromatin and, hence, increasing degree of cell differentiation. Changes in contents and distribution of SH-groups in cell cytoplasm indicate that keratin is accumulated in it and that keratinization processes in the mucous membrane epithelium increase. In this way it is shown that the densitometric parameters are informative on distribution of hetero- and euchromatin in nuclei and SH-groups in epitheliocytic cytoplasm of the mucous membrane in the oral wall for estimation of morphofunctional state of these cells, normal and under pathological conditions.

Duodenal Ulcer↗
PubMed2006

The photodissociation dynamics of NO2 at 308 nm and of NO2 and N2O4 at 226 nm.

Velocity-map ion imaging has been applied to the photodissociation of NO(2) via the first absorption band at 308 nm using (2 + 1) resonantly enhanced multiphoton ionization detection of the atomic O((3)P(J)) products. The resulting ion images have been analyzed to provide information about the speed distribution of the O((3)P(J)) products, the translational anisotropy, and the electronic angular momentum alignment. The atomic speed distributions were used to provide information about the internal quantum-state distribution in the NO coproducts. The data were found to be consistent with an inverted NO vibrational quantum-state distribution, and thereby point to a dynamical, as opposed to a statistical dissociation mechanism subsequent to photodissociation at 308 nm. Surprisingly, at this wavelength the O-atom electronic angular momentum alignment was found to be small. Probe-only ion images obtained under a variety of molecular-beam backing-pressure conditions, and corresponding to O atoms generated in the photodissociation of either the monomer, NO(2), or the dimer, N(2)O(4), at 226 nm, are also reported. For the monomer, where 226 nm corresponds to excitation into the second absorption band, the kinetic-energy release distributions are also found to indicate a strong population inversion in the NO cofragment, and are shown to be remarkably similar to those previously observed in the wavelength range of 193-248 nm. Mechanistic implications of this result are discussed. At 226 nm it has also been possible to observe directly O atoms from the photodissociation of the dimer. The O-atom velocity distribution has been analyzed to provide information about its production mechanism.

Journal Article↗
PubMed2000

A two-stage dose selection strategy in phase I trials with wide dose ranges.

At early stages of drug development, the maximum tolerated dose (MTD) must be determined in order to have a range of doses that can be safely administered in humans. This is necessary before the compound can be tested in phase II clinical trials to find the optimal dose in terms of clinical outcome. Although heavily criticized, traditional dose escalation methods are still widely used to estimate the MTD. The recently developed Continual Reassessment Method (CRM) and Logistic Dose Ranging Strategy (LDRS) offer advantages compared to the traditional approach, including improved estimation of the MTD. However, the CRM utilizes a prior distribution that must be specified before having any data from the current trial. The LDRS requires the use of hypothesized data through a seed data set established before the start of the trial. When a wide dose range needs to be tested, the assumed information (prior distribution or seed data set) can have a great impact on dosages used during the trial and on the final estimates of the MTD. This paper combines the LDRS and the traditional dose escalation procedure to suggest a practical two-stage method that provides reliable estimates through relatively easy computation, and yet requires almost no prior information.

Bayes Theorem↗
PubMed1994

India. Rajasthan adopts new strategy in teacher training.

In the State of Rajasthan, there are about 100,000 teachers working in remote places. Training this large number of teachers in population education is always tedious, time consuming and expensive. To be able to reach and train these teachers working in primary schools without extra effort, time and money, the State Institute of Educational Research and Training (SIERT) adopted a new approach for this purpose. The approach makes use of the block level administrative approach in Rajasthan, where the monthly pay is distributed at various pay centers in the block. Every month, about 50-60 teachers gather at each pay center to collect their salaries. These teachers also take this opportunity to spend some time to learn new academic information and solve their problems. The SIERT took this opportunity of group meetings by presenting lectures or talks on population education to these teachers. Experts were invited from the District Institute of Education and Training to give lectures on various topics such as concepts and needs for population education; teaching, strategies and organization of co-curricular activities and discussion on the textual material in the Hindi language and environmental education for primary school students. So far, these talks had been arranged at 150 pay centers covering around 7500 teachers in the year 1993.

Asia↗
PubMedDate not supplied

Regional anesthesia and chronic pain management in the 1920s and 1930s. The influence of the American Society of Regional Anesthesia.

BACKGROUND AND OBJECTIVES: Physicians in the 1920s and 1930s began to treat patients with chronic pain syndromes using regional anesthetic techniques for both temporary and permanent block of pain pathways. The founding of the American Society of Regional Anesthesia (ASRA) in 1923 provided a unique venue for the dissemination of information concerning regional anesthesia for both surgery and chronic pain management. METHODS: The growth of chronic pain management on a national basis was assessed by using the Quarterly Cumulative Index to the Medical Literature to trace the distribution of information on regional anesthesia. From the Minutes of Meeting of the American Society of Regional Anesthesia, presented papers and the discussion that followed were analyzed. RESULTS: Inquiries into regional anesthesia during the 1920s and 1930s predominantly dealt with technique. For the first time pain papers were listed under the regional anesthesia heading in the Index. The papers presented at ASRA meetings during the period helped develop the use of regional anesthesia for both chronic pain management and surgical anesthesia. CONCLUSIONS: The ASRA was instrumental in bringing together physicians interested in regional anesthesia and pain management. During the 1930s physician anesthetists came to predominate as the organization's officers and members and helped translate the work of the ASRA into a part of the knowledge required to be a specialist physician in anesthesia.

Anesthesia, Conduction↗
PubMed1998

Implementation and evaluation of information desk services provided by library technical assistants.

Changes in the role of information services librarians and in the health care environment have required a rethinking of the provision of reference services at the University of Illinois at Chicago Library of the Health Sciences. This is a report of a new service offered after that analysis. An information desk staffed by twenty-five library technical assistants was established. Details of staff training, scheduling, and data gathering for this new service are provided. After eight months of operation, an evaluation of services provided by the Information Desk was conducted. A combination of evaluation methodologies, both quantitative and qualitative, has been used to determine overall staff performance. Results from analysis of service statistics, structured observations of real-time services operations, and questionnaires distributed to information services librarians and to patrons are presented. The findings from this study are discussed in terms of comparison with similar studies in other libraries and identification of future research studies. The results confirm the value of the Information Desk and support the decision to continue this service model.

Evaluation Studies as Topic↗
PubMed2002

Using a geographical information system to map the distribution of dentists in Ohio.

BACKGROUND: Studies have reported that dental care is the highest unmet health care need in the United States and have evaluated this in terms of individual determinants of access and utilization. None of these studies took into consideration the provider issues of availability and accessibility or of spatial relations. The aim of this study was to analyze issues of provider availability and accessibility in Ohio using a geographical information system, or GIS. METHODS: Three Ohio databases were geocoded using GIS software. The databases included all 6,132 dentists licensed to practice in Ohio, 1,898 dentists who had billed the state Medicaid program in 1998 and safety-net clinics that provided free or low-cost care. Each practitioner was mapped at the county and ZIP code levels. RESULTS: Results are reported using maps at the county and ZIP code levels. The maps showed that 69.4 percent of dentists practiced in 12 metropolitan counties, 14 percent in 17 suburban counties and 16.6 percent in 59 rural counties (rural non-Appalachian counties plus Appalachian counties). In Appalachia, the dentist-to-population ratio was about one-half that of the metropolitan counties. CONCLUSION: Obvious disparities exist in the distribution of dentists in Ohio, particularly in rural and Appalachian counties. The need to increase the availability of dentists in these counties is evident. PRACTICE IMPLICATIONS: GIS is a useful tool for evaluating provider distribution and availability and planning programs to attract dentists to areas with small numbers of dentists.

Adult↗
PubMed1986

Genetics of Aedes albopictus.

Aedes albopictus is an important vector of dengue fever and dengue hemorrhagic fever in Southeast Asia. Its distribution extends from Madagascar to Hawaii and is currently expanding. From its proposed origin in Southeast Asia, Ae. albopictus has migrated as far as Mauritius and Madagascar to the west and Korea, Japan, Guam, Hawaii and other Pacific Islands to the east. In the continental United States, it was originally reported in the Texas area in August 1985 and is now well established in several states. This paper reviews information on distribution, cytology and genetics of Aedes albopictus. In addition, it includes comments on its competitive interaction with several other species. Relevant information on evolutionary genetics of certain other related sibling species is also included for comparative purposes.

Aedes↗
PubMed1989

Surveillance of invasive Streptococcus pneumoniae infection in Quebec, Canada, from 1984 to 1986: serotype distribution, antimicrobial susceptibility, and clinical characteristics.

Four hundred and sixty-eight strains of Streptococcus pneumoniae isolated from blood or normally sterile body fluids in 14 Quebec, Canada, hospitals between 1 July 1984 and 31 December 1986 were serotyped, their susceptibilities to antimicrobial agents were determined, and the laboratory data were correlated with the clinical information. The distribution pattern of the serogroups and serotypes was similar to that observed previously in Quebec and to that in other parts of Canada and in the United States. No regional variation was observed. The distribution of serogroups and serotypes was different in pediatric patients (less than 18 years old) when compared with that of adults (P less than 0.001). Overall, 94% of the strains were represented in 23-valent vaccine. The total mortality rate was 12.8% and increased with age: 1.6% in pediatric patients, 14.8% in patients 18 to 64 years old, and 31% in those greater than or equal to 65 years old (P less than 0.001). In patients 18 to 64 years old, the mortality rate was higher when an underlying condition that could have justified prior vaccination was present (P = 0.008). In patients greater than or equal to 65 years old, the mortality rates were similar in those with and those without underlying conditions, suggesting that vaccine use in all patients greater than or equal to 65 years old might be appropriate. Only six patients had received pneumococcal vaccine before infection. Only 15 strains (3.2%) were moderately susceptible or resistant to one or more of the antimicrobial agents tested. Six strains were moderately susceptible to penicillin G, and none was fully resistant.

Age Factors↗
PubMed2006

Influenza vaccination in German health care workers: effects and findings after two rounds of a nationwide awareness campaign.

In Germany, despite longstanding recommendations for influenza vaccination, uptake among health care workers (HCW) is poor. We conducted and evaluated a 2-year nationwide campaign to increase influenza vaccination rates among German HCW. The campaign was tailored to the results of a baseline survey and included the distribution of information material to all German hospitals (n approximately 2000) and engagement of stakeholders, such as professional HCW associations. Human and financial resources consisted of one full-time public health scientist (2 months) and approximately USD 45,000 to produce and distribute materials. We evaluated the intervention in a survey among a systematic sample of HCW in a sample of selected 20 hospitals. HCW were stratified by profession and asked to self-administer a questionnaire inquiring about self-perceived risk for influenza, belief of effectiveness of the vaccine, and influenza vaccination before the starting season (2003/2004) as well as the previous two seasons (2001/2002, 2002/2003). Three hundred and ninety-six of 800 (50%) HCW who were addressed in the evaluated hospitals participated in the evaluation survey. The overall influenza vaccination rate among respondents increased from 21% (2001/2002) to 26% (2003/2004), which was mostly due to a significant increase among physicians (2001/2002: 21%; 2003/2004: 31%; nurses: 20% and 22%, respectively). Significantly more physicians than nurses felt at increased risk for influenza and believed that the vaccine is very effective. Increased uptake among physicians (compared to nurses) was likely due to physicians' higher awareness of their risk and trust in the vaccine. In the future it may be necessary to address nurses differently than physicians. We conclude that a national campaign with very limited resources is feasible and capable of achieving measurable results in a short time frame.

Cross Infection↗
PubMed1991

The Human Genome Project: a paradigm for information management in the life sciences.

The major product of the Human Genome Project will be a series of linked data sets containing the genetic and physical location of all genes on each chromosome, plus the complete nucleotide sequence of the genome for humans and several model organisms. Here we summarize the current status of attempts to collect, analyze, and distribute this information in an electronically accessible form. Although formidable problems remain to be solved in the acquisition and adequate representation of the genetic, physical, and biological data, this project is a model for the rapid dissemination of genome and related information in biology and medicine.

Base Sequence↗
PubMed1992

Non-random distribution and co-localization of purine/pyrimidine-encoded information and transcriptional regulatory domains.

In order to detect sequence-based information predictive for the location of eukaryotic transcriptional regulatory domains, the frequencies and distributions of the 36 possible purine/pyrimidine reverse complement hexamer pairs was determined for test sets of real and random sequences. The distribution of one of the hexamer pairs (RRYYRR/YYRRYY, referred to as M1) was further examined in a larger set of sequences (> 32 genes, 230 kb). Predominant clusters of M1 and the locations of eukaryotic transcriptional regulatory domains were found to be associated and non-randomly distributed along the DNA consistent with a periodicity of approximately 1.2 kb. In the context of higher ordered chromatin this would align promoters, enhancers and the predominant clusters of M1 longitudinally along one face of a 30 nm fiber. Using only information about the distribution of the M1 motif, 50-70% of a sequence could be eliminated as being unlikely to contain transcriptional regulatory domains with an 87% recovery of the regulatory domains present.

Animals↗