Regional Differences In Rates Research Articles

Surveillance of pediatric injury hospitalizations in Southern California.

This study was designed to determine the incidence and causes of injury hospitalizations/fatalities to children less than 15 years of age. Central Orange County, California. Cases were identified through a population based hospital and coroner's office surveillance system. The sample consisted of children 0-14 years of age who were residents of the study area and sustained an injury between 1 January 1991 and 31 December 1992 resulting in hospitalization or death. Over the two year study period, 1361 children 0-14 years of age were hospitalized or died as a result of injury. This represents a crude annual injury rate of 318/100,000 children. Rates were highest for children less than 5 years--this age group sustained the highest rate for eight of nine specific causes of injury. Falls were the leading cause of hospitalizations for all ages. Pedestrian injuries were more common among children 1-4 years and 5-9 years, while bicycle injuries were more common among older children. This study, one of the first population based studies in a Southern California urban/suburban community, found lower rates of injury hospitalization than studies conducted over a decade ago. These lower rates may reflect changes in hospitalization trends and/or injury prevention programs. Comparisons with more recent studies in inner city communities in the north east also show regional differences in rates and causes. Injury prevention efforts should particularly address the higher injury rates among children less than 5 years of age. This study also illustrates the need for regional and local data to guide injury control.

Medical Decision Making, Gender, and Coronary Heart Disease

In order to assess possible gender bias in the diagnosis and treatment of heart disease, data from the National Hospital Discharge Survey (NHDS) for the years 1983–1989 were examined for gender differences and for variations among four major geographic areas of the United States (northeast, midwest, south, and west). Dramatic increases in the rates of diagnostic procedures and surgical treatments were found. Analyses of covariance additionally revealed significant regional differences in rates of procedures, with rates for the midwest generally high and those in the south and northeast generally low for angiocardiography (p <.0001), cardiac catheterization (p <.0001), angioplasty (p <.0001), and bypass (p <.0001). These differences were largely independent of disease epidemiology and suggest that practice variations may be shaped by considerations not strictly based on medical diagnoses. Analysis of covariance also revealed significant gender differences, with rates consistently higher among men for angiocardiography (p <.0001), catheterization (p <.0001), angioplasty (p <.001), and in bypass (p <.0001). On average, gender accounted for approximately 25% of the variance in rates of diagnosis and treatment. This suggests that gender may be a factor in decision making. The question of whether these results represent o ver utilization of services for men or underutilization of services for women is posed.

Migration in Colonial America: Evidence from the Militia Muster Rolls

The diversity of opinions about the extent and importance of migration during the colonial era testifies to the paucity of direct information on the subject. Beyond the desire for a purely demographic explanation of the differences in regional rates of population growth, the need for a better understanding of the changes in the supply and distribution of labor before the Industrial Revolution has spurred recent research on internal migration. Some of this work has grown out of studies of the censuses and vital records of various New England towns (such as those cited in Jones, 1981). However, although these sources testify that an individual existed in a specific place and time, and thus provide valuable indirect glimpses of migration, they rarely furnish the information necessary to locate him or her a second time—either earlier or later in the life cycle. Names appear and disappear from such lists over time, but several intervening assumptions are required before we can infer that migration was involved. Similarly, although differences in sex ratios and age distributions reflect the movement of population, they reveal little about the absolute magnitude or direction of net migration, let alone gross flows.

Denitrification and Nitrogen Fixation in Alaskan Continental Shelf Sediments

Rates of nitrogen fixation and denitrification were measured in Alaskan continental shelf sediments. In some regions, rates of nitrogen fixation and denitrification appeared to be equal; in other areas, rates were significantly different. Potential rates of denitrification were found to be limited primarily by the available nitrate substrate. Major regional differences in rates of denitrification were not statistically significant, but significant differences were found for nitrogen fixation rates in different regions of the Alaskan continental shelf. Estimated net losses of nitrogen from Bering Sea sediments were calculated as 1.8 x 10 g of N/yr. Experimental exposure of continental shelf sediments to petroleum hydrocarbons reduced rates of nitrogen fixation and denitrification in some cases but not others. Long-term exposure was necessary before a reduction in nitrogen fixation rates was observed; unamended rates of denitrification but not potential denitrification rates (NO(3) added) were depressed after exposure to hydrocarbons.

Late Cenozoic Sedimentation and Erosion on the Rio Grande Rise

The Rio Grande Rise is capped by a thick sequence of pelagic carbonate and reefal sediments, ranging in age from upper Cretaceous to Recent. The north flank of the Rise is dissected by deep erosional canyons which expose the near-horizontally layered calcareous strata as outcrops on the canyon walls. Lithologic and stratigraphic studies of twenty-two piston cores from a small area ($$~25 km^{2}$$) on the north flank allow an interpretation of the depositional environment on the Rise during the late Cenozoic, and place constraints on the origin of the erosional canyons. A major unconformity of Pliocene age was penetrated by 12 of the cores. Sediments beneath the unconformity range in age from upper Eocene to lower Pliocene, and correspond approximately in depth with that of equivalent strata recovered at DSDP Site 357 nearby. Pliocene-Pleistocene sediments above the unconformity show systematic regional differences in rate of accumulation, extent of reworking, and the presence of stratigraphic gaps. On the flanks of canyons, an apparently continuous depositional record extends back to ~370,000 y.B.P., with some evidence of effects of winnowing and terrigenous dilution. On the adjacent ridge axes, local variations (on a scale of km or less) in topography or near-bottom flow have created "pockets'* of virtually uninterrupted Pliocene-Pleistocene sedimentation separated by regions where Pleistocene sediments are virtually missing. The ridge axes are current-swept today, and contain considerable local variation in sedimentation rates and in the presence of erosional unconformities. Of several models considered to account for the origin and development of the erosional canyons, the one most consistent with the available lithologic and stratigraphic information includes: (a) initiation of canyon cutting during the late Cretaceous or early Tertiary when portions of the Rise were at or above sea level; (b) deepening of the canyons between the latest Miocene and late Pleistocene via a sequence of erosional episodes alternating with relatively quiescent depositional intervals; and (c) cessation of major canyon cutting in the late Pleistocene (~370,000 y.B.P.).

Interaction between inner cell mass and trophectoderm of the mouse blastocyst : II. The fate of the polar trophectoderm

Selective labelling of polar trophectoderm cells in early mouse blastocysts has allowed the fate of polar cells to be followed during in vitro and in vivo blastocyst development. Results show that there is cell movement from polar to mural regions as blastocysts grow. This indicates that trophectoderm cells directly opposite the inner cell mass are the oldest mural cells. However, after implantation polar cells invaginate into the blastocoelic cavity and contribute to the extra-embryonic ectoderm. It is suggested that the morphogenetic changes occurring in the mouse embryo at implantation result from the maintenance of a balance between (a) regional differences in rates of cellular proliferation, and (b) mechanical constraints on the direction in which growth can occur.

Regional Variation in the Deposition of Subepidermal Immunoglobulin in NZB/W F1 Mice: Association with Epidermal DNA Synthesis

We have previously reported that aging NZB/W F1 mice develop irregular immunoglobulin deposits along the dermalepidermal junction similar in appearance to those seen in the visibly normal skin of systemic lupus erythematosus patients. In this report we have extended this observation by showing that the frequency of these deposits varies from site to site in the skin of these animals. This regional variation in frequency of deposits was found to correlate positively with regional differences in rates of epidermal basal cell DNA synthesis as determined by autoradiography. These findings provide an explanation for the observed regional variation in frequency of subepidermal immunoglobulin deposition that occurs in human systemic lupus erythematosus.

Honesty as a Function of Geographic Region and City Size: Explorations of a 30-Year-Old Hypothesis

Merritt and Fowler's (1948) suggestion that lost letters containing money could be used to measure honesty in diverse social groups was studied. In Exp. I unstamped lost letters, some containing only an innocuous message, were dropped in Baltimore, St. Louis, Denver, and San Francisco. Significant theft was found in Baltimore and Denver. In Exp, II lost letters were dropped in two small Illinois cities and in 55 villages. Comparison of the results from St. Louis with the results from Exp. II indicated no relationship between theft rates and city size. Return rates for letters containing only the message were used as a measure of helpfulness. The results indicate regional differences in rates of helpfulness but the degree of helpfulness was not related to city size.

XENOPUS LAEVIS AND DEVELOPMENTAL BIOLOGY

XENOPUS LAEVIS AND DEVELOPMENTAL BIOLOGY

Regional differences in rates of insorption of sodium and water from the human large intestine.

Regional differences in sodium and water fluxes across the mucosa of the human colon were sought by comparing the arterial appearances of isotopes of sodium and water after instillation of test solutions containing them into four parts of the large intestine. Deuterium oxide and 24Na, in isotonic sodium chloride (154 mM), were placed in the cecum, transverse colon, descending colon, or rectum. The times of appearance and concentration of isotopes in serial samples of arterial blood were integrated with known plasma–disappearance curves to obtain rates of unidirectional flux from colonic lumen to blood (insorption). A gradient of insorption was found. Insorption was most rapid in the cecum and decreased progressively in the transverse colon, descending colon, and rectum. During steady-state perfusion of the entire large intestine the insorption rates of sodium and water, calculated by disappearance of isotopes from the lumen, were intermediate between those observed in the cecum and transverse colon during regional studies. Perfusion studies also revealed a close correlation between insorption and net absorption of sodium and water, implying that a regional gradient of net absorption may exist in the large intestine, analogous to the observed insorption gradient.

Biases in the Estimation of the Regression of Milk Production on Age

Summary The regression of production on age was computed by the paired and gross comparison methods within four geographical regions of the United States. A total of 405,330 lactations of registered DHIA Holsteins calving between 1951 and 1962 were studied. Bias due to selection was assumed to be the primary cause of variation between the paired and gross comparison regressions. These differences were found to be extreme only for the Western Midwest and Plains area. The standard DHIA age factors appear acceptable for most purposes in other areas, except for cows calving beyond 11 years of age. Gross regression curves for five regions were used as a criterion of regional differences in rate of maturity. Differences at immature ages were not large and do not indicate that cattle in the Deep South mature more slowly than those of more temperate areas.

Divisions of Freight Rates and the Interterritorial Rate Problem

Previous articleNext article No AccessDivisions of Freight Rates and the Interterritorial Rate ProblemThor HultgrenThor Hultgren Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Journal of Political Economy Volume 50, Number 1Feb., 1942 Article DOIhttps://doi.org/10.1086/255830 Views: 2Total views on this site PDF download Crossref reports no articles citing this article.

THE PROCESS OF REGENERATION IN HYDROIDS

Summary1. In the hydroids in general, and Tubularia and Corymorpha in particular, the stimulus for regeneration involves two factors: (1) removal of dominance exerted by either the fully formed hydranth or a regenerating hydranth, and (2) the presence of a gradient of oxygen at a localized region of the stem or a mass of cells isolated from the stem.2. Dominance, or the inhibitory effect of a regenerating region, can be explained either on the basis of electrical differences in potential which produce chemical inhibition, or as the competition of regions of the stem for hypothetical substances circulating in the stem and necessary for regeneration. As yet no single experiment has decided between these two explanations of dominance and both should be subjects for investigation.3. The regional differences in rate of regeneration are correlated with regional differences in the rate of oxygen consumption of the stem, and the rate of regeneration can be varied by varying the oxygen consumption of the stem. These regional differences in oxygen consumption are due to differences in the resting stem and are not caused by the regional differences in regeneration.4. Since the stimulus for regeneration can be traced to an oxygen gradient, which results in an oxygen consumption gradient in the tissues, there is little value in speaking of an organizer in hydranth formation. Any agent which will bring about the above conditions will be an organizer. It is, therefore, possible to speak of the following as organizers: (1) oxygen locally applied, (2) tissues that have a higher oxygen consumption than the surroundings, and, perhaps, (3) respiratory catalysts, when their effects are investigated. On the whole, it would be better to speak of the coenosarc as organizing itself in response to a stimulus. The manner in which the tissue responds by cell movements and change in form is, of course, entirely unknown.

Regional Differences in Rates and Rateable Values in England and Wales, 1921-1936

Purpose and scope of the study; reasons for excluding Scottish data, 624. — The four composite areas, 627.— The averages used, 628.— Conclusions apparent when data are graphed, 628.— Implications of these characteristics, 634.— The significance of underassessment, 636.— Revaluation in 1929 left much to be done, 638.— Organization employed, 641.— Distribution of government grants, 642.— Revaluation in 1934 brought some improvement, 646. — Derating of industrial properties, 648.— Opposition to derating, 651.— seq=a General conclusions concerning the significance of underassessment, 653.

Regional Differences in Rates and Rateable Values in England and Wales, 1921-1936

Regional Differences in Rates and Rateable Values in England and Wales, 1921-1936

Regional differences in rate of oxidations in the chick blastoderm as shown by susceptibility to hydrocyanic acid

Journal of Experimental ZoologyVolume 45, Issue 1 p. 141-157 Article Regional differences in rate of oxidations in the chick blastoderm as shown by susceptibility to hydrocyanic acid J. William Buchanan, J. William Buchanan Osborn Zoölogical Laboratory, Yale UniversitySearch for more papers by this author J. William Buchanan, J. William Buchanan Osborn Zoölogical Laboratory, Yale UniversitySearch for more papers by this author First published: May 1926 https://doi.org/10.1002/jez.1400450105Citations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume45, Issue1May 1926Pages 141-157 RelatedInformation