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At least 325 records · Page 18Linked to original sources
PubMed1998

Demography, clinical characteristics, psychological and abuse profiles, treatment, and long-term follow-up of patients with gastroparesis.

Patients with gastroparesis frequently present challenging clinical, diagnostic, and therapeutic problems. Data from 146 gastroparesis patients seen over six years were analyzed. Patients were evaluated at the time of initial diagnosis and at the most recent follow-up in terms of gastric emptying and gastrointestinal symptomatology. The psychological status and physical and sexual abuse history in female idiopathic gastroparesis patients were ascertained and an association between those factors and gastrointestinal symptomatology was sought. Eighty-two percent of patients were females (mean age: 45 years old). The mean age for onset of gastroparesis was 33.7 years. The etiologies in 146 patients are: 36% idiopathic, 29% diabetic, 13% postgastric surgery, 7.5% Parkinson's disease, 4.8% collagen vascular disorders, 4.1% intestinal pseudoobstruction, and 6% miscellaneous causes. Subgroups were identified within the idiopathic group: 12 patients (23%) had a presentation consistent with a viral etiology, 48% had very prominent abdominal pain. Other subgroups were gastroesophageal reflux disease and nonulcer dyspepsia (19%), depression (23%), and onset of symptoms immediately after cholecystectomy (8%). Sixty-two percent of women with idiopathic gastroparesis reported a history of physical or sexual abuse, and physical abuse was significantly associated with abdominal pain, somatization, depression, and lifetime surgeries. At the end of the follow-up period, 74% required continuous prokinetic therapy, 22% were able to stop prokinetics, 5% had undergone gastrectomy, 6.2% went onto gastric electrical stimulation (pacing), and 7% had died. At some point 21% had required nutrition support with a feeding jejunostomy tube or periods of parenteral nutrition. A good response to pharmacological agents can be expected in the viral and dyspeptic subgroups of idiopathics, Parkinson's disease, and the majority of diabetics, whereas a poorer outcome to prokinetics can be expected in postgastrectomy patients, those with connective tissue disease, a subgroup of diabetics, and the subset of idiopathic gastroparesis dominated by abdominal pain and history of physical and sexual abuse. Appreciation of the different etiologies and psychological status of the patients may help predict response to prokinetic therapy.

Adolescent↗
PubMed2003

An investigation of race and sex similarity effects in interviews: a multilevel approach to relational demography.

This research studied the effects of race and sex similarity on ratings in one-on-one highly structured college recruiting interviews (N = 708 interviewers and 12203 applicants for 7 different job families). A series of hierarchical linear models provided no evidence for similarity effects, although the commonly used D-score and analysis-of-variance-based interaction approaches conducted at the individual level of analysis yielded different results. The disparate results demonstrate the importance of attending to nested data structures and levels of analysis issues more broadly. Practically, the results suggest that organizations using carefully administered highly structured interviews may not need to be concerned about bias due to the mismatch between interviewer and applicant race or sex.

Adult↗
PubMed2001

Demography of the endangered North Atlantic right whale.

Northern right whales (Eubalaena glacialis) were formerly abundant in the northwestern Atlantic, but by 1900 they had been hunted to near extinction. After the end of commercial whaling the population was thought to be recovering slowly; however, evidence indicates that it has been declining since about 1990 (ref. 1). There are now fewer than 300 individuals, and the species may already be functionally extinct owing to demographic stochasticity or the difficulty of females locating mates in the vast Atlantic Ocean (Allee effect). Using a data set containing over 10,000 sightings of photographically identified individuals we estimated trends in right whale demographic parameters since 1980. Here we construct, using these estimates, matrix population models allowing us to analyse the causes of right whale imperilment. Mortality has increased, especially among mother whales, causing declines in population growth rate, life expectancy and the mean lifetime number of reproductive events between the period 1980-1995. Increased mortality of mother whales can explain the declining population size, suggesting that the population is not doomed to extinction as a result of the Allee effect. An analysis of extinction time shows that demographic stochasticity has only a small effect, but preventing the deaths of only two female right whales per year would increase the population growth rate to replacement level.

Animals↗
PubMed2004

Reduced genetic structure of the Iberian peninsula revealed by Y-chromosome analysis: implications for population demography.

Europe has been influenced by both intra- and intercontinental migrations. Since the Iberian peninsula was a refuge during the Last Glacial Maximum, demographic factors associated with contraction, isolation, subsequent expansion and gene flow episodes have contributed complexity to its population history. In this work, we analysed 26 Y-chromosome biallelic markers in 568 chromosomes from 11 different Iberian population groups and compared them to published data on the Basques and Catalans to gain insight into the paternal gene pool of these populations and find out to what extent major demographic processes account for their genetic structure. Our results reveal a reduced, although geographically correlated, Y-chromosomal interpopulation variance (1.2%), which points to a limited heterogeneity in the region. Coincidentally, spatial analysis of genetic distances points to a focal distribution of Y-chromosome haplogroups in this area. These results indicate that neither old or recent Levantine expansions nor North African contacts have influenced the current Iberian Y-chromosome diversity so that geographical patterns can be identified.

Chromosomes, Human, Y↗
PubMed2003

Long-distance colonization, isolation by distance, and historical demography in a relictual Mexican pinyon pine (Pinus nelsonii Shaw) as revealed by paternally inherited genetic markers (cpSSRs).

Pinus nelsonii is a relictual pinyon pine distributed across a wide altitudinal range in semiarid zones in Mexico near the border between the States of Nuevo León and Tamaulipas. It also occurs in small patches in the State of San Luis Potosí. Pinus nelsonii is classified in the monotypic subsection Nelsoniae, separated from other pinyon pines (subsection Cembroides), because it possesses several distinctive characters including persistent fascicle sheaths, connate needles, and a distinctive wood anatomy. In the present study, chloroplast simple sequence repeats (cpSSRs) were used to estimate genetic variation in most known populations (nine) of P. nelsonii. The genetic variation (HT = 0.73; 27 haplotypes in 256 individuals) is moderate when compared to other pine species. Population differentiation ranged between low and moderate (FST = 0.13 and RST = 0.05), as did the Nei and Goldstein genetic distances between populations. However, this pattern varied depending on whether the infinite alleles or stepwise mutation model was used. In the former case a significant isolation by distance was found, but not in the latter. A significant association between geographical and genetic structure in one clade, through a nested clade analysis, was found, which suggested long-distance colonization between 125000 and 309000 years ago. We found weak evidence for a population expansion. A mismatch distribution suggests that P. nelsonii populations underwent an expansion 4.25 times their size between 59000 and 146000 years ago. On the other hand, the populations' star-like phylogeny and a slight parabolic relationship between coalescence times and lineage number also suggest weak population expansion. Overall, this species appears to have been in demographic stasis for a large proportion of the time detected by the markers used.

Cluster Analysis↗
PubMed1999

Demography and prognostic factors of ocular injuries in South India.

PURPOSE: To evaluate the extent of visual recovery after multi-disciplinary approach of treatment in serious ocular injuries; to determine the prognostic factors associated with poor final visual outcome and suggest adequate precautionary measures. METHODS: A retrospective analysis of 325 consecutive patients with direct ocular trauma who were examined and treated at a tertiary eye care centre in South India over a 3-year period was undertaken. RESULTS: Males (86.8%) outnumbered the females (13.2%) and children (< 16 years) constituted 46.8% of the total affected population. Anterior segment was involved in 51.1%, the posterior segment in 8.9% and both anterior and posterior segments were involved in 31.4% of patients. Prompt and meticulous surgical treatment restored useful vision (better than or equal to 6/18) in 60.5% of patients. Post-treatment, a reduction in blindness and visual impairment rates in the affected eye with respect to WHO classification was 66.7 and 54.1% respectively (P < 0.0001). Two eyes needed prompt enucleation. The factors associated with visual impairment (visual acuity less than 6/18) were poor initial visual acuity, full chamber hyphema, endophthalmitis, retinal detachment, and vitreous haemorrhage. CONCLUSIONS: Direct ocular trauma remains an important potentially preventable cause of ocular morbidity, but the advent of modern surgical techniques can often restore useful vision in such situations. Mandatory use of protective eye wear at work, public health education including awareness on the part of parents to the potential dangers of some childrens' toys can to an extent help reduce ocular morbidity due to direct ocular trauma.

Accidents, Home↗
PubMed2001

Demography and etiology of acute leg ischemia.

Acute leg ischemia arguably is the most challenging condition that a vascular surgeon has to manage. Patients have widely different presentations, there are several available treatment options, and, yet, despite best efforts, the outcome remains poor. An understanding of the changes in population demographics in affluent western societies, set in an historical context, enables choices about therapy. A vascular unit serving a community including half a million people can expect to treat approximately 75 patients with acute leg ischemia per year. It is vital that a team approach is used to decide management because endovascular treatment with peripheral thrombolysis is increasingly important. The distinction between etiology of thrombosis or embolism remains important, although the diagnosis can never be conclusive. The severity of arterial ischemia is a more important determinant of outcome; optimal management, therefore, begins with stratification according to the severity of ischemia on admission to the hospital. Subsequent care lends itself to organization by care-pathway or guidelines that take into account the available local facilities.

Acute Disease↗
PubMed1993

Changing regional demography in the Federated States of Micronesia: contrasting planning challenges in an emerging Pacific nation.

"Island nations consisting of small landmasses separated by large expanses of ocean face particularly severe challenges in their quest for economic and social development. In this paper, planning concerns in one such nation, the Federated States of Micronesia (FSM), are examined. The study opens with a description of each of the four separate states in the FSM.... Regional aspects of FSM development are then examined by a statistical analysis of the geographical distribution of population in the individual states.... The study concludes with an assessment of the regional challenge of developing the FSM into an economically and culturally sustainable nation."

Demography↗
PubMed2002

The aging baboon: comparative demography in a non-human primate.

Why do closely related primate genera vary in longevity, and what does this teach us about human aging? Life tables of female baboons (Papio hamadryas) in two wild populations of East Africa and in a large captive population in San Antonio, Texas, provide striking similarities and contrasts to human mortality patterns. For captive baboons at the Southwest Foundation for Biomedical Research, we estimate the doubling time of adult mortality rate as 4.8 years. Wild females in free-living populations in Tanzania and in Kenya showed doubling times of 3.5 and 3.8 years, respectively. Although these values are considerably faster than the estimates of 7-8 years for humans, these primates share a demographic feature of human aging: within each taxon populations primarily vary in the level of Gompertz mortality intercept (frailty) and vary little in the demographic rate of aging. Environmental and genetic factors within taxa appear to affect the level of frailty underlying senescence. In contrast, primate taxa are differentiated by rates of demographic aging, even if they cannot be characterized by species-specific lifespan.

Aging↗
PubMed1998

Hypsographic demography: the distribution of human population by altitude.

The global distribution of the human population by elevation is quantified here. As of 1994, an estimated 1.88 x 10(9) people, or 33. 5% of the world's population, lived within 100 vertical meters of sea level, but only 15.6% of all inhabited land lies below 100 m elevation. The median person lived at an elevation of 194 m above sea level. Numbers of people decreased faster than exponentially with increasing elevation. The integrated population density (IPD, the number of people divided by the land area) within 100 vertical meters of sea level was significantly larger than that of any other range of elevations and represented far more people. A significant percentage of the low-elevation population lived at moderate population densities rather than at the highest densities of central large cities. Assessments of coastal hazards that focus only on large cities may substantially underestimate the number of people who could be affected.

Altitude↗
PubMed1998

Genetic traces of ancient demography.

Patterns of gene differences among humans contain information about the demographic history of our species. Haploid loci like mitochondrial DNA and the nonrecombining part of the Y chromosome show a pattern indicating expansion from a population of only several thousand during the late middle or early upper Pleistocene. Nuclear short tandem repeat loci also show evidence of this expansion. Both mitochondrial DNA and the Y chromosome coalesce within the last several hundred thousand years, and they cannot provide information about the population before their coalescence. Several nuclear loci are informative about our ancestral population size during nearly the whole Pleistocene. They indicate a small effective size, on the order of 10,000 breeding individuals, throughout this time period. This genetic evidence denies any version of the multiregional model of modern human origins. It implies instead that our ancestors were effectively a separate species for most of the Pleistocene.

Anthropology↗