55 research outputs found
Evolutionary consequences of fishing and their implications for salmon
We review the evidence for fisheries-induced evolution in anadromous salmonids. Salmon are exposed to a variety of fishing gears and intensities as immature or maturing individuals. We evaluate the evidence that fishing is causing evolutionary changes to traits including body size, migration timing and age of maturation, and we discuss the implications for fisheries and conservation. Few studies have fully evaluated the ingredients of fisheries-induced evolution: selection intensity, genetic variability, correlation among traits under selection, and response to selection. Most studies are limited in their ability to separate genetic responses from phenotypic plasticity, and environmental change complicates interpretation. However, strong evidence for selection intensity and for genetic variability in salmon fitness traits indicates that fishing can cause detectable evolution within ten or fewer generations. Evolutionary issues are therefore meaningful considerations in salmon fishery management. Evolutionary biologists have rarely been involved in the development of salmon fishing policy, yet evolutionary biology is relevant to the long-term success of fisheries. Future management might consider fishing policy to (i) allow experimental testing of evolutionary responses to exploitation and (ii) improve the long-term sustainability of the fishery by mitigating unfavorable evolutionary responses to fishing. We provide suggestions for how this might be done
NMFS / Interagency Working Group Evaluation of CITES Criteria and Guidelines.
EXECUTIVE SUMMARY: At present, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) criteria used to assess whether a population qualifies for inclusion in the CITES Appendices relate to (A) size of the population, (B) area of distribution of the population, and (C) declines in the size of the population. Numeric guidelines are provided as indicators of a small population (less than 5,000 individuals), a small subpopulation (less than 500 individuals), a restricted area of distribution for a population (less than 10,000 km2), a restricted area of distribution for a subpopula-tion (less than 500 km2), a high rate of decline (a decrease of 50% or more in total within 5 years or two generations whichever is longer or, for a small wild population, a decline of 20% or more in total within ten years or three generations whichever is longer), large fluctuations (population size or area of distribution varies widely, rapidly and frequently, with a variation greater than one order of magnitude), and a short-term fluctuation (one of two years or less).
The Working Group discussed several broad issues of relevance to the CITES criteria and guidelines. These included the importance of the historical extent of decline versus the recent rate of decline; the utility and validity of incorporating relative population productivity into decline criteria; the utility of absolute numbers for defining small populations or small areas; the appropriateness of generation times as time frames for examining declines; the importance of the magnitude and frequency of fluctuations as factors affecting risk of extinction; and the overall utility of numeric thresh-olds or guidelines
Anorgasmia in women
This article reports on the etiology and treatment of anorgasmia. Etiological factors include childhood and adolescent experiences, current individual attitudes, and lifestyle factors, as well as the quality and dynamics of past and present committed relationships. It is important to assess the nature of each of the previously mentioned factors in determining the nature of the orgasmic dysfunction as well as assisting in the development of a treatment plan. Treatment approaches for anorgasmia need to address individual factors (e.g., performance anxiety, poor body image) as well as interpersonal problems. A systemic treatment framework would appear to be the most useful approach to treat this sexual dysfunction, as this type of strategy identifies and treats the difficulties experienced by the anorgasmic woman within the total context of her life. Of course, this approach necessitates the involvement of the partner in therapy, and treatment is unlikely to be effective unless the problems experienced by both the woman and her partner are addressed. Limitations of past research in terms of inadequate evaluation of treatment, low sample sizes, and poorly defined interventions are discussed. Finally, directions for future research to advance our understanding of the most effective treatments for anorgasmia are considered. <br /
Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California
A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions
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Ecto- and arbuscular mycorrhizal symbiosis can induce tolerance to toxic pulses of phosphorus in jarrah (Eucalyptus marginata) seedlings
In common with many plants native to low P soils, jarrah (Eucalyptus marginata) develops toxicity symptoms upon exposure to elevated phosphorus (P). Jarrah plants can establish arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) associations, along with a non-colonizing symbiosis described recently. AM colonization is known to influence the pattern of expression of genes required for P uptake of host plants and our aim was to investigate this phenomenon in relation to P sensitivity. Therefore, we examined the effect on hosts of the presence of AM and ECM fungi in combination with toxic pulses of P and assessed possible correlations between the induced tolerance and the shoot P concentration. The P transport dynamics of AM (Rhizophagus irregularis and Scutellospora calospora), ECM (Scleroderma sp.), non-colonizing symbiosis (Austroboletus occidentalis), dual mycorrhizal (R. irregularis and Scleroderma sp.), and non-mycorrhizal (NM) seedlings were monitored following two pulses of P. The ECM and A. occidentalis associations significantly enhanced the shoot P content of jarrah plants growing under P-deficient conditions. In addition, S. calospora, A. occidentalis, and Scleroderma sp. all stimulated plant growth significantly. All inoculated plants had significantly lower phytotoxicity symptoms compared to NM controls 7 days after addition of an elevated P dose (30 mg P kg−1 soil). Following exposure to toxicity-inducing levels of P, the shoot P concentration was significantly lower in R. irregularis-inoculated and dually inoculated plants compared to NM controls. Although all inoculated plants had reduced toxicity symptoms and there was a positive linear relationship between rank and shoot P concentration, the protective effect was not necessarily explained by the type of fungal association or the extent of mycorrhizal colonization
Structural and magnetic properties of Lix(MnyFe1-y)PO4 electrode materials for Li-ion batteries
International audienceA series of LiMnyFe1-yPO4 samples have been prepared in the whole range 0≤y≤1. Chemical delithiation could be achieved to obtain MnyFe1-yPO4 in the range 0≤y≤0.8, keeping the same crystal phase (olivine structure, space group Pnma). The composition y=0.8 is the limit where the delithiated phase is still crystallized, but abruptly suffers strains at the molecular scale evidenced by both optical spectroscopy and X-ray diffraction. The analysis of the magnetic properties shows that all the samples are the concentration of impurities is negligible. The concentration of polarons, either holes associated to Li vacancies in LiMnyFe1-yPO4 or electrons associated to the existence of Li left in the matrix of MnyFe1-yPO4, is found to be small (≤ 1%) in all the samples. For y ≤0.6, all the Mn3+ ions MnyFe1-yPO4 are in the high spin state (S=2). At larger manganese concentration, however, the Mn3+ ions in excess of the critical concentration yc=0.6 undergo a transition to the low-spin state (S=1). As a consequence, and in contrast with prior works, we find that Mn0.8Fe0.2PO4 has magnetic interactions that are much smaller, and no antiferromagnetic ordering in this compound is detected, at least above 20 K. Antiferromagnetic ordering that had been reported so far for MnyFe1-yPO4 at large y-composition might come from incomplete delithiation. The spin transition of Mn3+ in concentration (y-yc) to the low-spin state is at the origin of the strain fields at the molecular scale that increase with y for y>0.6, and ultimately prevents the full delithiation for y>0.8. This result sheds light on the reason for the degradation of cathode properties in Mn-rich compounds of the heterosite-purpurite series, while the electrochemical properties are good in the range y ≤0.6 but only at slow rates, due to the very small hopping mobility of the small polaron
Evaluation of ex-vivo 9.4T MRI in post-surgical specimens from temporal lobe epilepsy patients
© 2017 Elsevier Masson SAS Purpose This study evaluates hippocampal pathology through usage of ultra-high field 9.4T ex-vivo imaging of resected surgical specimens in patients who have undergone temporal lobe epilepsy surgery. Method and materials This is a retrospective interpretation of prospectively acquired data. MRI scanning of resected surgical specimens from patients who have undergone temporal lobe epilepsy surgery was performed on a 9.4T small bore Varian MR magnet. Structural images employed a balanced steady-state free precession sequence (TrueFISP). Six patients (3 females; 3 males) were included in this study with an average age at surgery of 40.7 years (range 20Y_ 60) (one was used as a control reference). Two neuroradiologists qualitatively reviewed the ex-vivo MRIs of resected specimens while blinded to the histopathology reports for the ability to identify abnormal features in hippocampal subfield structures. Results The hippocampal subfields were reliably identified on the 9.4T ex-vivo scans in the hippocampal head region and hippocampal body region by both neuroradiologists in all 6 patients. There was high concordance to pathology for abnormalities detected in the CA1, CA2, CA3 and CA4 subfields. Detection of abnormalities in the dentate gyrus was also high with detection in 4 of 5 cases. The Cohen\u27s kappa between the two neuroradiologists was calculated at 0.734 SE = 0.102. Conclusions Ex-vivo 9.4T specimen imaging can detect abnormalities in CA1, CA2, CA3, CA4 and DG in both the hippocampal head and body. There was good concordance between qualitative findings and histopathological abnormalities for CA1, CA2, CA3, CA4 and DG
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