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Closer Proximity (closer + proximity)
Selected AbstractsAvailability of Safety Net Providers and Access to Care of Uninsured PersonsHEALTH SERVICES RESEARCH, Issue 5 2004Jack Hadley Objective. To understand how proximity to safety net clinics and hospitals affects a variety of measures of access to care and service use by uninsured persons. Data Sources. The 1998,1999 Community Tracking Study household survey, administered primarily by telephone survey to households in 60 randomly selected communities, linked to data on community health centers, other free clinics, and safety net hospitals. Study Design. Instrumental variable estimation of multivariate regression models of several measures of access to care (having a usual source of care, unmet or delayed medical care needs, ambulatory service use, and overnight hospital stays) against endogenous measures of distances to the nearest community health center and safety net hospital, controlling for characteristics of uninsured persons and other area characteristics that are related to access to care. The models are estimated with data from a nationally representative sample of uninsured people. Principal Findings. Shorter distances to the nearest safety net providers increase access to care for uninsured persons. Failure to account for the endogeneity of distance to safety net providers on access to care generally leads to finding little or no safety net effects on access. Conclusions. Closer proximity to the safety net increases access to care for uninsured persons. However, the improvements in access to care are relatively small compared with similar measures of access to care for insured persons. Modest expansion of the safety net is unlikely to provide a full substitute for insurance coverage expansions. [source] Increased glucose metabolism and ATP level in brain tissue of Huntington's disease transgenic miceFEBS JOURNAL, Issue 19 2008Judit Oláh Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by multifarious dysfunctional alterations including mitochondrial impairment. In the present study, the formation of inclusions caused by the mutation of huntingtin protein and its relationship with changes in energy metabolism and with pathological alterations were investigated both in transgenic and 3-nitropropionic acid-treated mouse models for HD. The HD and normal mice were characterized clinically; the affected brain regions were identified by immunohistochemistry and used for biochemical analysis of the ATP-producing systems in the cytosolic and the mitochondrial compartments. In both HD models, the activities of some glycolytic enzymes were somewhat higher. By contrast, the activity of glyceraldehyde-3-phosphate dehydrogenase was much lower in the affected region of the brain compared to that of the control. Paradoxically, at the system level, glucose conversion into lactate was enhanced in cytosolic extracts from the HD brain tissue, and the level of ATP was higher in the tissue itself. The paradox could be resolved by taking all the observed changes in glycolytic enzymes into account, ensuing an experiment-based detailed mathematical model of the glycolytic pathway. The mathematical modelling using the experimentally determined kinetic parameters of the individual enzymes and the well-established rate equations predicted the measured flux and concentrations in the case of the control. The same mathematical model with the experimentally determined altered Vmax values of the enzymes did account for an increase of glycolytic flux in the HD sample, although the extent of the increase was not predicted quantitatively. This suggested a somewhat altered regulation of this major metabolic pathway in HD tissue. We then used the mathematical model to develop a hypothesis for a new regulatory interaction that might account for the observed changes; in HD, glyceraldehyde-3-phosphate dehydrogenase may be in closer proximity (perhaps because of the binding of glyceraldehyde-3-phosphate dehydrogenase to huntingtin) with aldolase and engage in channelling for glyceraldehyde-3-phosphate. By contrast to most of the speculation in the literature, our results suggest that the neuronal damage in HD tissue may be associated with increased energy metabolism at the tissue level leading to modified levels of various intermediary metabolites with pathological consequences. [source] Hypoxia-based habitat compression of tropical pelagic fishesFISHERIES OCEANOGRAPHY, Issue 6 2006ERIC D. PRINCE Abstract Large areas of cold hypoxic water occur as distinct strata in the eastern tropical Pacific (ETP) and Atlantic oceans as a result of high productivity initiated by intense nutrient upwelling. We show that this stratum restricts the depth distribution of tropical pelagic marlins, sailfish, and tunas by compressing the acceptable physical habitat into a narrow surface layer. This layer extends downward to a variable boundary defined by a shallow thermocline, often at 25 m, above a barrier of cold hypoxic water. The depth distributions of marlin and sailfish monitored with electronic tags and average dissolved oxygen (DO) and temperature profiles show that this cold hypoxic environment constitutes a lower habitat boundary in the ETP, but not in the western North Atlantic (WNA), where DO is not limiting. Eastern Pacific and eastern Atlantic sailfish are larger than those in WNA, where the hypoxic zone is much deeper or absent. Larger sizes may reflect enhanced foraging opportunities afforded by the closer proximity of predator and prey in compressed habitat, as well as by the higher productivity. The shallow band of acceptable habitat restricts these fishes to a very narrow surface layer and makes them more vulnerable to over-exploitation by surface gears. Predictably, the long-term landings of tropical pelagic tunas from areas of habitat compression have been far greater than in surrounding areas. Many tropical pelagic species in the Atlantic Ocean are currently either fully exploited or overfished and their future status could be quite sensitive to increased fishing pressures, particularly in areas of habitat compression. [source] Australian biogeographical connections and the phylogeny of large genera in the plant family MyrtaceaeJOURNAL OF BIOGEOGRAPHY, Issue 7 2003Pauline Y. Ladiges Abstract Aim To compare the phylogeny of the eucalypt and melaleuca groups with geological events and ages of fossils to discover the time frame of clade divergences. Location Australia, New Caledonia, New Guinea, Indonesian Archipelago. Methods We compare published molecular phylogenies of the eucalypt and melaleuca groups of the plant family Myrtaceae with geological history and known fossil records from the Cretaceous and Cenozoic. Results The Australasian eucalypt group includes seven genera, of which some are relictual rain forest taxa of restricted distribution and others are species-rich and widespread in drier environments. Based on molecular and morphological data, phylogenetic analyses of the eucalypt group have identified two major clades. The monotypic Arillastrum endemic to New Caledonia is related in one clade to the more species-rich Angophora, Corymbia and Eucalyptus that dominate the sclerophyll vegetation of Australia. Based on the time of rifting of New Caledonia from eastern Gondwana and the age of fossil eucalypt pollen, we argue that this clade extends back to the Late Cretaceous. The second clade includes three relictual rain forest taxa, with Allosyncarpia from Arnhem Land the sister taxon to Eucalyptopsis of New Guinea and the eastern Indonesian archipelago, and Stockwellia from the Atherton Tableland in north-east Queensland. As monsoonal, drier conditions evolved in northern Australia, Arnhem Land was isolated from the wet tropics to the east and north during the Oligocene, segregating ancestral rain forest biota. It is argued also that the distribution of species in Eucalyptopsis and Eucalyptus subgenus Symphyomyrtus endemic in areas north of the stable edge of the Australian continent, as far as Sulawesi and the southern Philippines, is related to the geological history of south-east Asia-Australasia. Colonization (dispersal) may have been aided by rafting on micro-continental fragments, by accretion of arc terranes onto New Guinea and by land brought into closer proximity during periods of low sea-level, from the Late Miocene and Pliocene. The phylogenetic position of the few northern, non-Australian species of Eucalyptus subgenus Symphyomyrtus suggests rapid radiation in the large Australian sister group(s) during this time frame. A similar pattern, connecting Australia and New Caledonia, is emerging from phylogenetic analysis of the Melaleuca group (Beaufortia suballiance) within Myrtaceae, with Melaleuca being polyphyletic. Main conclusion The eucalypt group is an old lineage extending back to the Late Cretaceous. Differentiation of clades is related to major geological and climatic events, including rifting of New Caledonia from eastern Gondwana, development of monsoonal and drier climates, collision of the northern edge of the Australian craton with island arcs and periods of low sea level. Vicariance events involve dispersal of biota. [source] Losartan and Ozagrel Reverse Retinal Arteriolar Constriction in Non-Obese Diabetic MiceMICROCIRCULATION, Issue 5 2008Seungjun Lee ABSTRACT Objective: Reductions in retinal blood flow are observed early in diabetes. Venules may influence arteriolar constriction and flow; therefore, we hypothesized that diabetes would induce the constriction of arterioles that are in close proximity to venules, with the constriction mediated by thromboxane and angiotensin II. Methods: Using nonobese diabetic (NOD) mice, retinal measurements were performed three weeks following the age at which glucose levels exceeded 200 mg/dL, with accompanying experiments on age-matched normoglycemic NOD mice. The measurements included retinal arteriolar diameters and red blood cell velocities and were repeated following an injection of the thromboxane synthase inhibitor, ozagrel. Mice were subdivided into equal groups and given drinking water with or without the angiotensin II receptor antagonist, losartan. Results: Retinal arterioles were constricted in hyperglycemic mice, with a significant reduction in flow. However, not all arterioles were equally affected; the vasoconstriction was limited to arterioles that were in closer proximity to venules. The arteriolar vasoconstriction (mean arteriolar diameters = 51 ± 1 vs. 61 ± 1 , m in controls; p < 0.01) was eliminated by both ozagrel (61 ± 2 , m) and losartan (63 ± 2 , m). Conclusions: Venule-dependent arteriolar vasoconstriction in NOD mice is mediated by thromboxane and/or angiotensin II. [source] Behavioral responses of one western lowland gorilla (Gorilla gorilla gorilla) group at Bai Hokou, Central African Republic, to tourists, researchers and trackersAMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2010Michelle Klailova Abstract Gorilla tourism, widely perceived as a lucrative industry, is propelled by strong market demand with programs in five countries and for three of four gorilla subspecies. Human presence may negatively affect wild gorillas, potentially lowering immunity and increasing the likelihood of acquiring human-borne disease. Yet, behavioral impacts of humans on wild gorilla behavior remain largely unexplored, particularly for western lowland gorillas. We evaluate the impact of tourist presence, human observer numbers (tourists, trackers, and researchers), and human observer distance on the behavior of one habituated gorilla group at Bai Hokou, Central African Republic. Behavioral data were collected for more than 12 months from January 2007. Of silverback aggressive events, 39% (N=229) were human directed, but 65% were low-level soft barks. Adult females, and one in particular, were responsible for the highest number of aggressive events toward humans. Humans maintained closer proximity to the silverback when tourists were present, although tourist numbers had no significant impact on overall group activity budgets or rates of human-directed aggression. However, as research team size increased, group feeding rates decreased. Close observer,silverback distance correlated with a decrease in his feeding rates and an increase in human monitoring. He directed less aggression toward observers at distances >10,m, although observers spent 48.5% of time between 6 and 10,m of the silverback. We discuss gorilla personality as a factor in human-directed aggression. We explore whether the current 7,m distance limit governing gorilla tourism, based on disease transmission risks, is sufficient considering the potential behavioral stressor of close human presence. We recommend increasing minimum observation distance to >10,m where possible, decreasing observer group sizes, particularly after a visit consisting of maximum numbers and restricting tourist access to 1 visit/day. Am. J. Primatol. 72:897,906, 2010. © 2010 Wiley-Liss, Inc. [source] Sexual behavior across ovarian cycles in wild black howler monkeys (Alouatta pigra): male mate guarding and female mate choiceAMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2009Sarie Van Belle Abstract We studied two multimale,multifemale groups of black howler monkeys (Alouatta pigra) during a 14-month study (June 2006,July 2007) in Palenque National Park, Mexico to evaluate the ways in which their sexual behavior changes across ovarian cycles. We analyzed 231 fecal samples, collected every 2.2±1.4 days from five females. For four females, estradiol and progesterone profiles revealed an average (±SE) cycle length of 18.3±1.4 days. Copulations occurred significantly more frequently during the periovulatory period (POP), defined as the estimated day of ovulation ±3 days (N=18). This was largely the result of cycling females soliciting sexual interactions during their POPs. Females directed their solicitations significantly more often toward "central" males of their group, who had close spatial associations with females at other times, compared with "noncentral" males, who did not associate closely with females. Central males rarely solicited sexual interactions, but instead monitored the females' reproductive status by sniffing their genitals, and maintained significantly closer proximity to females during their POPs, suggesting male mate guarding when conceptions are most likely to occur. Our findings indicate that the reproductive strategies of black howler central males and females coincide, highly skewing mating opportunities toward central males. Black howler females, however, occasionally choose to copulate with noncentral resident males or extra-group males during their POPs, undermining the ability of central males to monopolize all reproductive opportunities. Am. J. Primatol. 71:153,164, 2009. © 2008 Wiley-Liss, Inc. [source] A comparative histological analysis of human pulp following direct pulp capping with Propolis, mineral trioxide aggregate and DycalAUSTRALIAN DENTAL JOURNAL, Issue 1 2010A Parolia Abstract Background:, Permanent teeth pulp exposures have traditionally been treated with calcium hydroxide pulp capping. The aim of this study was to investigate the response of human pulp tissue which were mechanically exposed to a new material, Propolis and compare it with two existing and commonly used pulp capping agents (mineral trioxide aggregate and Dycal). Methods:, Thirty-six intact human premolars were mechanically exposed. Teeth were divided into six groups of 6 teeth each and were capped with Propolis, mineral trioxide aggregate and Dycal. Final restoration was done with posterior composite resin using light cured glass ionomer cement as a liner. The teeth were then extracted on the 15th or the 45th day and processed for histological evaluation. Results:, Differences in inflammatory response and dentine bridge formation of the exposed pulp to the three different materials were statistically calculated using chi-square test and were found to be non-significant. There was more pulp inflammation in teeth treated with Dycal than with Propolis and MTA on the 15th as well as on the 45th day. Propolis and MTA showed bridge formation in more teeth, and the bridges were in closer proximity to pulp capping material than teeth treated with Dycal on the 45th day. Conclusions:, The response of pulps to Propolis as a pulp capping agent was comparable to MTA and Dycal. [source] | ||||||||||