1,804 research outputs found
Contraceptive confidence and timing of first birth in Moldova: an event history analysis of retrospective data
Objectives: To test the contraceptive confidence hypothesis in a modern context. The hypothesis is that women using effective or modern contraceptive methods have increased contraceptive confidence and hence a shorter interval between marriage and first birth than users of ineffective or traditional methods. We extend the hypothesis to incorporate the role of abortion, arguing that it acts as a substitute for contraception in the study context.Setting: Moldova, a country in South-East Europe. Moldova exhibits high use of traditional contraceptive methods and abortion compared with other European countries.Participants: Data are from a secondary analysis of the 2005 Moldovan Demographic and Health Survey, a nationally representative sample survey. 5377 unmarried women were selected.Primary and secondary outcome measures: The outcome measure was the interval between marriage and first birth. This was modelled using a piecewise-constant hazard regression, with abortion and contraceptive method types as primary variables along with relevant sociodemographic controls.Results: Women with high contraceptive confidence (modern method users) have a higher cumulative hazard of first birth 36?months following marriage (0.88 (0.87 to 0.89)) compared with women with low contraceptive confidence (traditional method users, cumulative hazard: 0.85 (0.84 to 0.85)). This is consistent with the contraceptive confidence hypothesis. There is a higher cumulative hazard of first birth among women with low (0.80 (0.79 to 0.80)) and moderate abortion propensities (0.76 (0.75 to 0.77)) than women with no abortion propensity (0.73 (0.72 to 0.74)) 24?months after marriage.Conclusions: Effective contraceptive use tends to increase contraceptive confidence and is associated with a shorter interval between marriage and first birth. Increased use of abortion also tends to increase contraceptive confidence and shorten birth duration, although this effect is non-linear—women with a very high use of abortion tend to have lengthy intervals between marriage and first birth
The correlates of natural method use in Moldova: is natural method use associated with poverty and isolation?
Natural method use is often associated with high levels of unwanted births and induced abortions. This study investigates the correlates of natural method use in Moldova, a country with one of the highest proportions of natural contraceptive users in Europe. We hypothesize that economic and spatial disadvantage increase the reliance on natural methods whereas exposure to FP programs decreases the probability of natural method use. The analysis considers a sub-sample of 5860 sexually-active women from the 2005 Demographic and Health Survey. Results from multilevel multinomial models, controlling for relevant characteristics and data structure, show that economic disadvantage increases the probability of natural method use; but the overall effect is small. Higher FP media exposure reduces natural method use; however this effect attenuates with age. We conclude that FP efforts directed towards the poorest may have limited impact, but interventions targeted at older women could reduce the burden of unwanted pregnancies
Evidence for Decline in the Unionidae of the East Branch Rocky River, Ohio
A survey of freshwater mussels (Mollusca: Bivalvia: Unionidae) was conducted for the East Branch Rocky River, Ohio, during the summer of 2006. Development in this watershed is moderate though rapidly expanding, particularly in the upstream reaches. Perhaps as a consequence, a preliminary search failed to reveal any live mussels in the river in 2003 . The present report is of an extensive survey covering 21 two-hour timed searches for live mussels and shells combined with visual assessments of disturbance and tests for water quality at each site. All searches were visual or by feeling for mussels embedded in the stream bottom where visibili ty was poor. These surveys produced only 34 live animals and 287 empty shells, which included live specimens of Lampsilis radiata /uteo/a, Lasmigona costata, Lasmigona compressa, and Strophitus undulatus as well as fresh shells of Pyganodon grandis. The few sites that contained live animals and fresh shells were isolated, while worn shells were distributed more evenly throughout the river, suggesting a wider distribution of mussels in the past. Present water quality appeared good, and, therefore, the relatively low density and spatial isolation of unionids may reflect local geomorphologic factors combined with historic and current land usage
Major features and forcing of high‐latitude northern hemisphere atmospheric circulation using a 110,000‐year‐long glaciochemical series
The Greenland Ice Sheet Project 2 glaciochemical series (sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, and chloride) provides a unique view of the chemistry of the atmosphere and the history of atmospheric circulation over both the high latitudes and mid‐low latitudes of the northern hemisphere. Interpretation of this record reveals a diverse array of environmental signatures that include the documentation of anthropogenically derived pollutants, volcanic and biomass burning events, storminess over marine surfaces, continental aridity and biogenic source strength plus information related to the controls on both high‐ and low‐frequency climate events of the last 110,000 years. Climate forcings investigated include changes in insolation of the order of the major orbital cycles that control the long‐term behavior of atmospheric circulation patterns through changes in ice volume (sea level), events such as the Heinrich events (massive discharges of icebergs first identified in the marine record) that are found to operate on a 6100‐year cycle due largely to the lagged response of ice sheets to changes in insolation and consequent glacier dynamics, and rapid climate change events (massive reorganizations of atmospheric circulation) that are demonstrated to operate on 1450‐year cycles. Changes in insolation and associated positive feedbacks related to ice sheets may assist in explaining favorable time periods and controls on the amplitude of massive rapid climate change events. Explanation for the exact timing and global synchroneity of these events is, however, more complicated. Preliminary evidence points to possible solar variability‐climate associations for these events and perhaps others that are embedded in our ice‐core‐derived atmospheric circulation records
Seasonal, Taxonomic, and Local Habitat Components of Bird-window Collisions on an Urban University Campus in Cleveland, OH
Author Institution: Department of Biological, Geological & Environmental Sciences, Cleveland State UniversityAuthor Institution: Department of Ornithology, Cleveland Museum of Natural HistoryMigrating birds congregate near the shores of Lake Erie during migration and may be funneled through small green spaces within the urban matrix of Great Lake coastal cities, where they are at risk of higher mortality from manmade structures. Bird deaths due to window collisions were assessed amongst a complex of low-rise buildings (<30 m) on a university campus in Cleveland,
OH. A 1.8 km route was surveyed three times per week during a 12-month period. Deaths were tested against null hypotheses that season, taxonomy, and building attributes had no significant relationship with avian mortality. We recovered 271 dead birds of 50 species, all of which were consistent with regional bird lists and Neotropical-Nearctic and North American migrants through Ohio. Deaths occurred non-randomly by week, month, and migratory status with 90 percent of deaths occurring during spring and fall migrations. Consequently, migrants (warblers: 34 percent of species richness, 30 percent of deaths; sparrows: 14 percent
of richness, 35 percent of deaths) were observed nine times more frequently than residents. Neotropical-Nearctic migrant species outnumbered North American migrant species. Although there was no statistical difference between the compass direction of a building facade and the number of deaths, deaths were not randomly distributed among campus buildings. Rather, significantly more deaths occurred at facades with higher percentages of glass. The presence of trees within 5 m of a window and the reflection of trees in windows were also associated with a greater risk of fatality. A better understanding of the factors associated with bird-window collisions is a pressing issue in the conservation of migratory birds
The Dominion Range Ice Core, Queen Maud Mountains, Antarctica - General Site and Core Characteristics with Implications
The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including ice surface, ice thickness, bore-hole temperature, mean annual net accumulation, crystal size, crystal fabric, oxygen-isotope composition, and examples of ice chemistry and isotopic composition of trapped gases
Ice-core Records and Ozone Depletion—Potential for a Proxy Ozone Record
Time-series of the ionic composition in polar ice cores can provide detailed direct and proxy records of seasonal to Millenial scale fluctuations in climate, atmospheric chemistry, and volcanic activity. Even though problems of species-source links and air/snow fractionation have not all been entirely resolved,the fact remains that ice cores currently hold the best hope of retrieving detailed paleo-atmospheric records. While direct links between the chemistry in ice cores and the ozone depletion phenomenon cannot be guaranteed, ice-core records provide the only means by which signals related to the ozone cycle can be produced for pre-measurement periods or for unmonitored sites. We propose that measurements of nitrate and/or chloride in polar snow/ice samples may provide proxy records of ozone depletion because of the role these species play in the ozone cycle (e.g., see summary review by Schoeberl and Krueger 1986). Heterogeneous chemical reactions in the ant-arctic atmosphere involving catalyzing agents such as chlorine monoxide, bromine monoxide, and/or nitrogen oxides are known to be effective in reducing ozone concentrations through their effect on the general reaction: oxygen plus ozone forms 202(e.g., McElroy et al. 1986a). Removal of nitrogen oxides by condensation from polar stratospheric clouds (e.g., Toon et al.1986; McElroy et al. 1986b; Crutzen and Arnold 1986) triggered particularly by cooling in the stratosphere helps set the stage for more efficient removal of ozone by reactions with chlorine monoxide and bromine monoxide (e.g., McElroy et al. 1986a). These reactions may result in increased concentrations of nitrate and chloride in polar snow/ice cores
Assessing Causes of Change in the Freshwater Mussels (Bivalvia: Unionidae) in the Black River, Ohio
Habitat destruction is believed to be the number one cause of the decline in unionid mussels. Around the world, cities, towns and agriculture alter the structure of watersheds, and the Black River in Ohio may be a typical example. We investigated the diversity and abundance of unionid mussels in this watershed and compared results to urbanization locations, to site-specific appearance of the habitat and to a 1997 fish survey, as host species are another factor important to the distribution of unionid mussels. Although shells were found for 21 species, only 11 of these species were found alive. Seven of the species represented only by shells occurred only in the urbanized lower main stem of the river and less than five shells were found for each. Most of these shells were old and worn. Furthermore, the present assemblage in the main stem varied from shells obtained at a nearby archeological site, and from a voucher set of species obtained at the turn of the 20th Century. Mussel communities higher in the river and those in tributaries were less diverse, but abundance of the species present was higher than in the main stem. A lack of fish hosts may limit mussel diversity, as hosts for several species present in the main stem do not reside higher in the watershed. Overall, mussel assemblages in the Black River appear typical for the region with relatively abundant, but low diversity communities upstream of the cities that line Lake Erie\u27s coast and diverse, but small and potentially threatened, populations in the urban regions
An Ice-Core-Based, Late Holocene History for the Transantarctic Mountains, Antarctica
Ice core records (major anions and cations, MSA, oxygen isotopes and particles) developed from two shallow (~200 m depth) sites in the Transantarctic Mountains provide documentation of much of the Holocene paleoenvironmental history of this region. From the more southerly site, Dominion Range, an ~7000-year-long record reveals change in the influence of tropospheric transport to the region. At this site, milder conditions and increased tropospheric inflow prior to ~1500 yr BP are characterized by increased seasalt (ss), terrestrial and marine biogenic inputs. Increased persistence and/or extent of polar stratospheric clouds accompanying generally cooler conditions characterize much of the period since ~1500 yr BP. From the more northerly site, Newall Glacier, the dramatic influence of the retreat of grounded ice from McMurdo Sound dated at[Denton et al., 1989] dominates much of the ice core record. This regional environmental change is documented by massive influxes to the core site of evaporitic salts from areas exposed during low lake level stands. During the past ~150 yr, both Dominion Range and Newall Glacier appear to be experiencing an overall increase in the exposure of ice-free terrain
Major Features and Forcing of High-atitude Northern Hemisphere Atmospheric Circulation using a 110,000-year-long Glaciochemical Series
The Greenland Ice Sheet Project 2 glaciochemical series (sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, and chloride) provides a unique view of the chemistry of the atmosphere and the history of atmospheric circulation over both the high latitudes and mid-low latitudes of the northern hemisphere. Interpretation of this record reveals a diverse array of environmental signatures that include the documentation of anthropogenically derived pollutants, volcanic and biomass burning events, storminess over marine surfaces, continental aridity and biogenic source strength plus information related to the controls on both high- and low-frequency climate events of the last 110,000 years. Climate forcings investigated include changes in insolation of the order of the major orbital cycles that control the long-term behavior of atmospheric circulation patterns through changes in ice volume (sea level), events such as the Heinrich events (massive discharges of icebergs first identified in the marine record) that are found to operate on a 6100-year cycle due largely to the lagged response of ice sheets to changes in insolation and consequent glacier dynamics, and rapid climate change events (massive reorganizations of atmospheric circulation) that are demonstrated to operate on 1450-year cycles. Changes in insolation and associated positive feedbacks related to ice sheets may assist in explaining favorable time periods and controls on the amplitude of massive rapid climate change events. Explanation for the exact timing and global synchroneity of these events is, however, more complicated. Preliminary evidence points to possible solar variability-climate associations for these events and perhaps others that are embedded in our ice-core-derived atmospheric circulation records
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