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PubMed2000

Geography is destiny: global nosocomial infection control.

The global nature of the emergence and spread of multiresistant bacteria has resulted in a slow response from governmental bodies, but surveillance networks are being set up and there is evidence, cited in this review, of an element of cooperation among professional bodies. Most developed and many developing countries have recognized the need for nosocomial infection control.

Journal Article↗
PubMed1996

The logical geography of concepts and shared responsibilities concerning research misconduct.

The relationship between grantee institutions and the federal government, a familiar concern apropos alleged misconduct in research, ramifies along conceptual, sequential, organizational, and other lines. It is argued in this essay that the appropriate federal interest in penalizing untruthfulness is the avoidance of future waste. Ineligibility for grants may be justified as an anticipation that one who resorts to untruthfulness betrays lack of distinction, a divergence from a consensus about what is permissible in research, or both, and that these features will be a fatal selective disadvantage in competition for grants. Sequential responsibility-institutions first, government second-characterizes the enforcement system that leads to government determinations of ineligibility. Not as clear is the government's blending of investigation and adjudication, a circumstance that renders more important the availability of hearing rights, not their curtailment. For institutions, confusion may arise whether to adopt more strict proscriptions of misconduct than the government standard that they must enforce. Institutional standards surpass the mere avoidance of wrong. Nonetheless it is argued that a more strict definition of "misconduct" would be imprudent. The federal government may proscribe misrepresentation, plagiarism and misuse of others' ideas, and damage to tangible property used in research; there is then no obvious other conduct to be proscribed. To proscribe other conduct could create a standard for science faculty that does not apply to others and would install a punitive system when mechanisms already obtain for evaluation. The logic is different for research practice rules. These are not intellectually profound, but they sensibly address subjects such as data recordation, data retention, and authorship. It would be incongruous for these to be incorporated by reference into a vague federal concept of "misconduct," a point that tells against any imprecision in the latter. But practice rules may symbolize commitment to high standards of truthfulness and obviate some specific practices that occasion untruthfulness.

Biomedical Research↗
PubMed1997

Geography of AIDS-associated Kaposi's sarcoma in Europe.

BACKGROUND: Classical Kaposi's sarcoma (KS) is about four times more common in southern Europeans than in northern Europeans. OBJECTIVE: To describe the epidemiology of AIDS-associated KS (AIDS-KS) in Europe and to determine whether it occurs with increased frequency in southern Europe. METHODS: Analysis of the 'European non-aggregate AIDS data set', as of September 1995. Countries with a cumulative total of > or = 50 KS cases as the presenting manifestation of AIDS were included. Homosexual men were excluded from south versus non-south comparisons because of possible confounding effects due to their route of HIV transmission. RESULTS: KS was the presenting manifestation of AIDS for 13.3% (16,367 out of 122,679) of men and 2% (491 out of 24,826) of women. In all countries, the risk for KS was higher in individuals who acquired HIV infection via sexual rather than parenteral transmission. Among AIDS patients, there is little difference by sex in the risk of KS in injecting drug users (IDU) or transfusion recipients. The percentage with KS increased with age among homosexual and bisexual men, from 10% in the age group 15-19 years to 23% in the age group 30-39 years. In all countries, the percentage with KS declined over time. The risk of KS was not significantly higher in southern Europe. The percentage with KS in southern Europe was slightly lower than in northern Europe (P > 0.1) in male IDU (1.8% versus 2.1%), and only slightly higher (P > 0.1) in female IDU (1.5% versus 1.1%), in male transfusion recipients (3.5% versus 3.0%), in female transfusion recipients (2.4% versus 2.3%), and in both heterosexual men (7.5% versus 6.2%) and women (2.0% versus 1.6%) excluding those originating from countries where heterosexual HIV transmission is frequent. CONCLUSIONS: The strong geographic predilection described for classical KS in southern Europe was not seen for AIDS-KS. If KS is caused by a viral infection in an immunodeficient host, our findings suggest the geographical variations in classical KS are not due to variation in prevalence of the causative virus but may be due to geographical variations in the prevalence of a form of mild immunodeficiency.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Helicobacter pylori genotypes in Israeli children: the significance of geography.

BACKGROUND: There is substantial genetic variation among different isolates of Helicobacter pylori, which may affect the clinical outcome. The aims of this study were to find the common H. pylori genotypes in Israeli children and to look for a possible genotype-phenotype correlation. METHODS: Ninety-eight H. pylori cultures were isolated from antral biopsy specimens of symptomatic Israeli children and were analyzed for vacA and iceA genotype and cagA and cagE status by polymerase chain reaction. RESULTS: cagA and cagE genes were present in only 25.5% and 24.5%, respectively. The common vacA genotype was s2m2, which was found in 65%. Eleven specimens (11%) contained multiple vacA genotypes. iceA1 was found in 37% and iceA2 in 52% of cases. Both iceA alleles were found in 11%. Increased prevalence of iceA1 and cagE were observed in children with duodenal disease, although it did not reach significance. CONCLUSIONS: The low prevalence of cagA and the high prevalence of vacA genotype s2m2 in Israeli pediatric patients are different from the genotype prevalence reported globally. However, similar findings have been reported in Egypt, indicating a possible geographic influence. There is a possible correlation between duodenal ulcer and cag E and ice A1 genotype, but the power of the study was too low to prove it.

Adolescent↗
PubMed1999

The geography of sexual partnerships in Baltimore: applications of core theory dynamics using a geographic information system.

OBJECTIVE: Gonorrhea has a focused geographic distribution characterized by high incidence rates in defined "core" areas and decreased incidence as the radial distance from the central core increases. Dense cor group transmission has long been hypothesized. METHODS: We have previously mapped sexually transmitted disease (STD) rates in Baltimore census tracts using STD morbidity data interfaced with a geographic information system. Core areas were defined using a standard definition based on gonorrhea distribution. We studied spatial distance patterns between sexual partners, using the residential addresses of 572 individuals, representing 286 dyad partnerships recruited as part of an epidemiology and behavioral study. To determine if partners lived closer together than would be expected, a modified bootstrap algorithm using Monte Carlo models was developed to compare the distances between partners' residences and all other possible residences. RESULTS: Two distinct (east and west) core areas were previously identified. Compared with randomly selected Baltimore addresses, partners tended to reside closer to one another than would be expected by chance (z = -1.8), with a median distance of 1.7 kilometers. Within the core areas, women resided a median of 547 meters from their partner, and men resided a median of 339 meters from their reported partners. When all partnerships were considered, the median distance was 1,699 meters. Of the 500 simulation models, the minimum median distance was 4,889 meters. CONCLUSIONS: Partners of patients in core areas in Baltimore live remarkably close to one another, and the partner selection patterns in general indicate nonrandom distribution. Geographic information system-determined patterns of STD patients residing in hyperendemic census tracts support the core theory of disease transmission. In these areas, targeted geographically based interventions may be warranted.

Adult↗
PubMed1994

The geography of AIDS: patterns of urban and rural migration.

We sought to describe the migration patterns of patients infected with the human immunodeficiency virus (HIV) who seek health services in North Carolina. Of 390 consecutive adult patients with HIV seen at one tertiary care medical center in the southeastern United States in the summer of 1990, 340 (87%) were approached, and 325 (83%) completed surveys. Thirty-seven percent of respondents thought they had been infected and 20% were told they were infected with HIV while living outside of North Carolina. One in five patients thought they had been infected while living in a rural county and more than half now live in rural communities (population of < 50,000). Sixty percent of patients had moved to North Carolina since 1980; 61% of these were North Carolina natives. Injecting drug users were more likely than those with other modes of exposure to HIV to have been diagnosed with HIV infection out of state (34% vs 18%). Patients' reasons for moving to North Carolina included social support (88%), health reasons (54%), and better work/educational opportunities (52%). We found that most patients with HIV who seek health care services in North Carolina live in rural areas with their families, and a substantial proportion migrated in after they were diagnosed out of state. Characterizing these migration patterns is crucial for predicting the diffusion of HIV to rural areas; designing AIDS prevention strategies, education, and health service needs; and assessing federal HIV care funding policies.

Acquired Immunodeficiency Syndrome↗
PubMed2003

HIV-1 infection among civilian applicants for US military service, 1985 to 2000: epidemiology and geography.

OBJECTIVES: This study examined demographic and geographic correlates of HIV-1 prevalence among civilian applicants for US military service. METHODS: HIV-1 test results and demographic and geographic data were available for 5.3 million applicants. RESULTS: Between October 1985 and December 2000, a total of 5,340,694 individuals applied to join one of the armed service branches of the US military. Overall, HIV-1 prevalence was 0.80 per 1000 applicants (95% CI: 0.78-0.82), with 4276 applicants testing positive for HIV-1 infection. Prevalence declined over the 16-year period from a high of 2.89 per 1000 applicants in 1985 to 0.36 per 1000 applicants in 2000. The majority of applicants (82.7%) were male, and the majority of HIV-1 cases (89.4%) occurred in men. HIV-1 prevalence was higher among African Americans (2.47/1000) and Hispanics (0.90/1000) than among white applicants (0.36/1000). HIV-1 prevalence was lowest in the West North Central region of the United States (0.33/1000) and highest in the Middle Atlantic region (1.61/1000) and Puerto Rico (3.56/1000). CONCLUSIONS: Civilian applicants for US military service comprise a unique cohort for following trends in the evolving HIV-1 epidemic.

Adolescent↗
PubMed1995

Genealogies and geography.

Any sample of genes traces back to a single common ancestor. Each gene also has other properties: its sequence, its geographic location and the phenotype and fitness of the organism that carries it. With sexual reproduction, different genes have different genealogies, which gives us much more information, but also greatly complicates population genetic analysis. We review the close relation between the distribution of genealogies and the classic theory of identity by descent in spatially structured populations, and develop a simple diffusion approximation to the distribution of coalescence times in a homogeneous two-dimensional habitat. This shows that when neighbourhood size is large (as in most populations) only a small fraction of pairs of genes are closely related, and only this fraction gives information about current rates of gene flow. The increase of spatial dispersion with lineage age is thus a poor estimator of gene flow. The bulk of the genealogy depends on the long-term history of the population; we discuss ways of inferring this history from the concordance between genealogies across loci.

Gene Frequency↗
PubMed2001

Locomotor performance of Drosophila melanogaster: interactions among developmental and adult temperatures, age, and geography.

We explored the extent to which a phenotypic trait (walking speed) of Drosophila melanogaster is influenced by population, developmental temperature, adult temperature, and age. Our goals were to estimate the importance of these factors and to test the beneficial acclimation hypothesis. We measured speed of flies from two populations (the Congo and France) that developed at different temperatures (18, 25, and 29 degrees C) and were tested at different temperatures (18, 25, and 29 degrees C) and ages (2, 7, 13 days). Not surprisingly, speed increased strongly with test temperature. Speed was generally greatest for flies reared at an intermediate developmental temperature, contrary to the beneficial acclimation hypothesis, which predicts that speed would be greatest when influenced by interactions involving population. For example, speed was greatest for flies from France that developed at a low temperature, but for flies from the Congo that developed at a high temperature. The impact of developmental temperature declined with age. Surprisingly, speed actually increased with age for flies raised and maintained at a low temperature, but decreased with age for flies raised and maintained at an intermediate or at a high temperature. Thus, walking performance is highly dynamic phenotypically, complicating potential attempts to predict responses to selection on performance.

Acclimatization↗
PubMed2004

Reconciling geography and genealogy: phylogeography of giant freshwater prawns from the Lake Carpentaria region.

There is convincing geological evidence for the historical existence of an ancient lake on the Australian-New Guinea continental shelf during the late Pleistocene. Lake Carpentaria was a vast fresh- to brackishwater lake that would presumably have provided habitat for, and facilitated gene flow among, aquatic taxa that tolerate low to moderate salinities in this region. Moreover, it has been argued that the outflow of Papua New Guinea's Fly River was diverted westward into Lake Carpentaria during this period, although this hypothesis is controversial. We predicted that these events, if a true history, would have promoted gene flow and population growth via range-expansion events in the giant freshwater prawn (Macrobrachium rosenbergii) and restricted gene flow subsequently by way of a vicariant event as sea levels rose during the late Pleistocene, and a marine environment replaced Lake Carpentaria. We tested these hypotheses using phylogeographical and phylogenetic analyses of mitochondrial DNA variation in M. rosenbergii populations sampled from the Lake Carpentaria region. Our results support the hypothesis that Lake Carpentaria facilitated gene flow among populations of M. rosenbergii that are today isolated, but contest claims of a westward diversion of the Fly River. We inferred the timing of initial expansion in the 'Lake Carpentaria lineage' and found the timing of this event to be broadly concordant with geological dating of the formation of Lake Carpentaria. Reconciling geological and molecular data, as presented here, provides a powerful framework for investigating the influence of historical earth history events on the distribution of biological (i.e. molecular) diversity.

Animals↗
PubMed2006

From genes to geography: a genetic similarity rule for arthropod community structure at multiple geographic scales.

We tested the hypothesis that leaf modifying arthropod communities are correlated with cottonwood host plant genetic variation from local to regional scales. Although recent studies found that host plant genetic composition can structure local dependent herbivore communities, the abiotic environment is a stronger factor than the genetic effect at increasingly larger spatial scales. In contrast to these studies we found that dependent arthropod community structure is correlated with both the cross type composition of cottonwoods and individual genotypes within local rivers up to the regional scale of 720,000 km(2) (Four Corner States region in the southwestern USA). Across this geographical extent comprising two naturally hybridizing cottonwood systems, the arthropod community follows a simple genetic similarity rule: genetically similar trees support more similar arthropod communities than trees that are genetically dissimilar. This relationship can be quantified with or without genetic data in Populus.

Animals↗