1,010 research outputs found
Meta-Analysis of Relationships between Human Offtake, Total Mortality and Population Dynamics of Gray Wolves (Canis lupus)
Following the growth and geographic expansion of wolf (Canis lupus) populations reintroduced to Yellowstone National Park and central Idaho in 1995â1996, Rocky Mountain wolves were removed from the endangered species list in May 2009. Idaho and Montana immediately established hunting seasons with quotas equaling 20% of the regional wolf population. Combining hunting with predator control, 37.1% of Montana and Idaho wolves were killed in the year of delisting. Hunting and predator control are well-established methods to broaden societal acceptance of large carnivores, but it is unprecedented for a species to move so rapidly from protection under the Endangered Species Act to heavy direct harvest, and it is important to use all available data to assess the likely consequences of these changes in policy. For wolves, it is widely argued that human offtake has little effect on total mortality rates, so that a harvest of 28â50% per year can be sustained. Using previously published data from 21 North American wolf populations, we related total annual mortality and population growth to annual human offtake. Contrary to current conventional wisdom, there was a strong association between human offtake and total mortality rates across North American wolf populations. Human offtake was associated with a strongly additive or super-additive increase in total mortality. Population growth declined as human offtake increased, even at low rates of offtake. Finally, wolf populations declined with harvests substantially lower than the thresholds identified in current state and federal policies. These results should help to inform management of Rocky Mountain wolves
Rapid Recovery of Damaged Ecosystems
Background: Recent reports on the state of the global environment provide evidence that humankind is inflicting great
damage to the very ecosystems that support human livelihoods. The reports further predict that ecosystems will take
centuries to recover from damages if they recover at all. Accordingly, there is despair that we are passing on a legacy of
irreparable damage to future generations which is entirely inconsistent with principles of sustainability.
Methodology/Principal Findings: We tested the prediction of irreparable harm using a synthesis of recovery times compiled
from240 independent studies reported in the scientific literature. We provide startling evidence that most ecosystems globally
can, given human will, recover from very major perturbations on timescales of decades to half-centuries.
Significance/Conclusions: Accordingly, we find much hope that humankind can transition to more sustainable use of
ecosystems
Relationships Between Neuronal Birthdates and Tonotopic Positions in The Mouse Cochlear Nucleus
Tonotopy is a key anatomical feature of the vertebrate auditory system, but little is known about the mechanisms underlying its development. Since date of birth of a neuron correlates with tonotopic position in the cochlea, we investigated if it also correlates with tonotopic position in the cochlear nucleus (CN). In the cochlea, spiral ganglion neurons are organized in a basal to apical progression along the length of the cochlea based on birthdates, with neurons in the base (responding to highâfrequency sounds) born early around mouse embryonic day (E) 9.5â10.5, and those in the apex (responding to lowâfrequency sounds) born late around E12.5â13.5. Using a lowâdose thymidine analog incorporation assay, we examine whether CN neurons are arranged in a spatial gradient according to their birthdates. Most CN neurons are born between E10.5 Änd E13.5, with a peak at E12.5. A second wave of neuron birth was observed in the dorsal cochlear nucleus (DCN) beginning on E14.5 and lasts until E18.5. Large excitatory neurons were born in the first wave, and small local circuit neurons were born in the second. No spatial gradient of cell birth was observed in the DCN. In contrast, neurons in the anteroventral cochlear nucleus (AVCN) were found to be arranged in a dorsal to ventral progression according to their birthdates, which are aligned with the tonotopic axis. Most of these AVCN neurons are endbulbâinnervated bushy cells. The correlation between birthdate and tonotopic position suggests testable mechanisms for specification of tonotopic position
Susceptibility to Predation Affects Trait-Mediated Indirect Interactions by Reversing Interspecific Competition
Numerous studies indicate that the behavioral responses of prey to the presence of predators can have an important role in structuring assemblages through trait-mediated indirect interactions. Few studies, however, have addressed how relative susceptibility to predation influences such interactions. Here we examine the effect of chemical cues from the common shore crab Carcinus maenas on the foraging behavior of two common intertidal gastropod molluscs. Of the two model consumers studied, Littorina littorea is morphologically more vulnerable to crab predation than Gibbula umbilicalis, and it exhibited greater competitive ability in the absence of predation threat. However, Littorina demonstrated a greater anti-predator response when experimentally exposed to predation cues, resulting in a lower level of foraging. This reversed the competitive interaction, allowing Gibbula substantially increased access to shared resources. Our results demonstrate that the susceptibility of consumers to predation can influence species interactions, and suggest that inter-specific differences in trait-mediated indirect interactions are another mechanism through which non-consumptive predator effects may influence trophic interactions
Effects of Compressed Speech Theory Applied to Health Occupations Education Instruction
The purpose of this study was to investigate (a) normal, (b) 40% compressed, and (c) 80% compressed speech presentations of conceptual data for the âBurnsâ chapter from the Multimedia Standard First Aid book. The material was presented to randomly assigned intact groups of health occupations education 9th, 10th, llth, and 12th grade students from two country school systems in a southern state. There were overall differences among posttest scores attributed to presentation method adjusted, in an analysis of partial variance, for reading level and pretest score
High rate of unintended pregnancy among pregnant women in a maternity hospital in CĂłrdoba, Argentina: a pilot study
<p>Abstract</p> <p>Background</p> <p>Although Argentina has a new law on Reproductive Health, many barriers continue to exist regarding provision of contraceptive methods at public healthcare facilities.</p> <p>Methods</p> <p>We asked 212 pregnant women selected at random at the Maternity and Neonatal Hospital, CĂłrdoba, Argentina, to participate in our descriptive study. Women were asked to complete a structured questionnaire. The objectives were to determine the rate of unintended pregnancies, reasons for not using contraception, past history of contraceptive use, and intended future use.</p> <p>Results</p> <p>Two hundred women responded to the questionnaire. Forty percent of the women stated that they had never used contraception and pregnancy was declared unintended by 65%. In the unintended pregnancy group, almost 50% of women said that they had not been using a contraceptive method because they were "unaware about contraception", and 25% stated that their contraceptive method had failed. Almost 85% of women stated that they intended to use contraception after delivery.</p> <p>Conclusion</p> <p>Approximately two-thirds of all pregnancies in this sample were unintended. Although the data is limited by the small sample size, our findings suggest that our government needs to invest in counseling and in improving the availability and access to contraceptive methods.</p
Attitudes of Experienced Health Occupations Teachers Toward Disabled Persons
The purpose of the research was to study the effects of different instructional strategies and selected demographic variables on experienced health occupations teachers* attitudes toward disabled persons using three groups: independent study, lecture, and film, in a pre/pose experimental design. MANOVA revealed no significant group effects for instructional strategies. A sequential partitioning of the sum of squares in univariate analyses revealed differences in years of occupational experience, number of courses studied, years of teaching experience, and highest degree earned. Special coursework to teach the handicapped was found to contribute to a positive attitude toward disabled students. This finding suggests that states should require special preparation for all teachers
FROM INDIVIDUALS TO ECOSYSTEM FUNCTION: TOWARD AN INTEGRATION OF EVOLUTIONARY AND ECOSYSTEM ECOLOGY
An important goal in ecology is developing general theory on how the species composition of ecosystems is related to ecosystem properties and functions. Progress on this front is limited partly because of the need to identify mechanisms controlling functions that are common to a wide range of ecosystem types. We propose that one general mechanism, rooted in the evolutionary ecology of all species, is adaptive foraging behavior in response to predation risk. To support our claim, we present two kinds of empirical evidence from plantâbased and detritusâbased food chains of terrestrial and aquatic ecosystems. The first kind comes from experiments that explicitly trace how adaptive foraging influences ecosystem properties and functions. The second kind comes from a synthesis of studies that individually examine complementary components of particular ecosystems that together provide an integrated perspective on the link between adaptive foraging and ecosystem function. We show that the indirect effects of predators on plant diversity, plant productivity, nutrient cycling, trophic transfer efficiencies, and energy flux caused by consumer foraging shifts in response to risk are qualitatively different from effects caused by reductions in prey density due to direct predation. We argue that a perspective of ecosystem function that considers effects of consumer behavior in response to predation risk will broaden our capacity to explain the range of outcomes and contingencies in trophic control of ecosystems. This perspective also provides an operational way to integrate evolutionary and ecosystem ecology, which is an important challenge in ecology
Effectiveness of medical abortion with mifepristone and buccal misoprostol through 59 gestational days
BACKGROUND: From 2001 to March 2006, Planned Parenthood Federation of America (Planned Parenthood) health centers throughout the United States provided medical abortions principally by a regimen of oral mifepristone, followed 24-48 h later by vaginal misoprostol. In late March 2006, analyses of serious uterine infections following medical abortions led Planned Parenthood to change the route of misoprostol administration and to employ additional measures to minimize subsequent serious uterine infections. In August 2006, we conducted an extensive audit of medical abortions with the new buccal misoprostol regimen so that patients could be given accurate information about the success rate of the new regimen. OBJECTIVES: We sought to evaluate the effectiveness of the buccal medical abortion regimen and to examine correlates of its success during routine service delivery. METHODS: In 2006, audits were conducted in 10 large urban service points to estimate the success rates of the buccal regimen. Success was defined as medical abortion without vacuum aspiration. These audits also permitted estimates of success rates with oral misoprostol following mifepristone in a subset in which 98% of the subjects stemmed from two sites. RESULTS: The effectiveness of the buccal misoprostol-mifepristone regimen was 98.3% for women with gestational ages below 60 days. The oral misoprostol-mifepristone regimen, used by 278 women with a gestational age below 50 days, had a success rate of 96.8%. CONCLUSION: In conjunction with 200 mg of mifepristone, use of 800 mcg of buccal misoprostol up to 59 days of gestation is as effective as the use of 800 mcg of vaginal misoprostol up to 63 days of gestation.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3766037/?tool=pubme
- âŠ