The role of menopause and reproductive senescence in a long-lived social mammal

<p>Abstract</p> <p>Background</p> <p>Menopause is a seemingly maladaptive life-history trait that is found in many long-lived mammals. There are two competing evolutionary hypotheses for this phenomenon; in the adaptive view of menopause, the cessation of reproduction may increase the fitness of older females; in the non-adaptive view, menopause may be explained by physiological deterioration with age. The decline and eventual cessation of reproduction has been documented in a number of mammalian species, however the evolutionary cause of this trait is unknown.</p> <p>Results</p> <p>We examined a unique 30-year time series of killer whales, tracking the reproductive performance of individuals through time. Killer whales are extremely long-lived, and may have the longest documented post-reproductive lifespan of any mammal, including humans. We found no strong support for either of the adaptive hypotheses of menopause; there was little support for the presence of post-reproductive females benefitting their daughter's reproductive performance (interbirth interval and reproductive lifespan of daughters), or the number of mature recruits to the population. Oldest mothers (> 35) did appear to have a small positive impact on calf survival, suggesting that females may gain experience with age. There was mixed support for the grandmother hypothesis – grandoffspring survival probabilities were not influenced by living grandmothers, but grandmothers may positively influence survival of juveniles at a critical life stage.</p> <p>Conclusion</p> <p>Although existing data do not allow us to examine evolutionary tradeoffs between survival and reproduction for this species, we were able to examine the effect of maternal age on offspring survival. Our results are consistent with similar studies of other mammals – oldest mothers appear to be better mothers, producing calves with higher survival rates. Studies of juvenile survival in humans have reported positive benefits of grandmothers on newly weaned infants; our results indicate that 3-year old killer whales may experience a positive benefit from helpful grandmothers. While our research provides little support for menopause evolving to provide fitness benefits to mothers or grandmothers, our work supports previous research showing that menopause and long post-reproductive lifespans are not a human phenomenon.</p

Nature-based guided imagery as an intervention for state anxiety

Anxiety is a significant mental health issue in modern society and empirical research into effective interventions to address anxiety has been extensive. Spending time in nature is one approach that has demonstrated anxiolytic effects. However, in some situations and contexts spending time in nature in order to reduce anxiety symptoms may not be possible. For example, in therapeutic settings delivered in a space with no access or exposure to any nature stimuli in the immediate surrounding environment. Guided imagery (GI) has also proven to be effective for reducing anxiety symptoms. Thus, nature-based GI might help to overcome the limitation of access to nature and strengthen the impact of GI interventions

Cellular and nuclear morphological variability within a single species of the toxigenic dinoflagellate genus Gambierdiscus: relationship to life-cycle processes

Dinoflagellates belonging to the genus Gambierdiscus are the causative agent of ciguatera fish poisoning (CFP). This syndrome, which is widespread in tropical and subtropical regions, has recently been reported also in temperate latitudes. Taxonomic studies of Gambierdiscus have yet to completely couple the morphological features of member species with their genetics. In this study, the cellular and nuclear morphology of a single strain of one species of Gambierdiscus was determined in cells grown under different culture conditions. The results showed a wide-ranging variability of cell sizes, together with a clear relationship between cell size and nuclear morphology. Thus, small cells were associated with round to oval or slightly U-shaped nuclei and large cells with obviously U-shaped nuclei. Most cells exhibited the typical anterio-posteriorly compressed lenticular, shape of Gambierdiscus, with the exception of a few small globular-shaped specimens. In all cells, regardless of their size, the arrangement of the thecal plates was typical of lenticular Gambierdiscus. Dividing cells were consistently the largest. In these cells, nuclear morphology, karyokinesis, and cytokinesis were characterized. Cells underwent division only during the dark period, thus demonstrating their spontaneous synchronized division. Cellular forms related to the sexual cycle were also present in the cultures and included gamete pairs and putative meiotic planozygotes. The effect of the culture medium was studied by means of principal component analyses, which showed a positive correlation between the medium used and nuclear size and shape but not cell size.Versión del editor3,083

Reflective-verbal language and reverie in a qualitative interview

In contrast to dominant approaches to therapy research that look at outcomes and focus on large samples, another primary strand of research considers microphenomenal processes and focuses on small samples. This study contributes to the latter genre in regard to the implicit impact of language. Aim: This study aims to apply relational psychotherapeutic thinking about empathic dialogue, specifically the concepts of reflective-verbal language and reverie, to qualitative interviewing. Methodology: An example from a small-scale study about emotionally evocative language is reviewed in detail, focusing on the interviewer’s phenomenological experience of her conversation with a participant in a qualitative interview. Findings: The authors argue that the interviewer’s reflexive awareness of her reveries and the reflective verbal nature of the research dialogue gave her an alternative perspective on the participant’s (and her own) experience. Implications: The study highlights the value within research and practice of maintaining awareness of language at a microphenomenal level, using techniques based on the principles of psychological therapy

Efficacy of nano-hydroxyapatite prepared by an aqueous solution combustion technique in healing bone defects of goat

The present study was undertaken to evaluate porous hydroxyapatite (HAp), the powder of which was prepared by a novel aqueous solution combustion technique, as a bone substitute in healing bone defects in vivo, as assessed by radiologic and histopathologic methods, oxytetracycline labeling, and angiogenic features in Bengal goat. Bone defects were created in the diaphysis of the radius and either not filled (group I) or filled with a HAp strut (group II). The radiologic study in group II showed the presence of unabsorbed implants which acted as a scaffold for new bone growth across the defect, and the quality of healing of the bone defect was almost indistinguishable from the control group, in which the defect was more or less similar, although the newly formed bony tissue was more organized when HAp was used. Histologic methods showed complete normal ossification with development of Haversian canals and well-defined osteoblasts at the periphery in group II, whereas the control group had moderate fibro-collagenization and an adequate amount of marrow material, fat cells, and blood vessels. An oxytetracycline labeling study showed moderate activity of new bone formation with crossing-over of new bone trabeculae along with the presence of resorption cavities in group II, whereas in the control group, the process of new bone formation was active from both ends and the defect site appeared as a homogenous non-fluoroscent area. Angiograms of the animals in the control group showed uniform angiogenesis in the defect site with establishment of trans-transplant angiogenesis, whereas in group II there was complete trans-transplant shunting of blood vessel communication. Porous HAp ceramic prepared by an aqueous combustion technique promoted bone formation over the defect, confirming their biologic osteoconductive property

Species-specific responses to atmospheric carbon dioxide and tropospheric ozone mediate changes in soil carbon

We repeatedly sampled the surface mineral soil (0–20 cm depth) in three northern temperate forest communities over an 11-year experimental fumigation to understand the effects of elevated carbon dioxide (CO 2 ) and/or elevated phyto-toxic ozone (O 3 ) on soil carbon (C). After 11 years, there was no significant main effect of CO 2 or O 3 on soil C. However, within the community containing only aspen ( Populus tremuloides Michx.), elevated CO 2 caused a significant decrease in soil C content. Together with the observations of increased litter inputs, this result strongly suggests accelerated decomposition under elevated CO 2. In addition, an initial reduction in the formation of new (fumigation-derived) soil C by O 3 under elevated CO 2 proved to be only a temporary effect, mirroring trends in fine root biomass. Our results contradict predictions of increased soil C under elevated CO 2 and decreased soil C under elevated O 3 and should be considered in models simulating the effects of Earth’s altered atmosphere.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78639/1/j.1461-0248.2009.01380.x.pd

Global geographies of innovation diffusion: the case of the Australian cattle industry

The geographies and histories of the introduction of cattle breeds to Australia in the period since white settlement are documented as an example of the diffusion of agricultural innovations. Three phases of development are identified: a colonial expansion phase from the late eighteenth to the early twentieth century during which a number of primarily British cattle breeds were imported by the colonial settlers; an innovative phase in the mid twentieth century when both governments and private interests sought to produce or import new breeds deemed to be better adapted to Australian environments; and a multifunctional phase in recent decades. In this final phase, government deregulation and new technologies, such as the long distance transport of genetic packages, have facilitated the importation and development of many new cattle breeds in Australia.While this has produced a significant rise in the total number of breeds represented nationally, many recent and historic breeds currently exhibit extremely small numbers and a few generally well-established breeds such as Holstein, Hereford and Angus still dominate the national herd. This study of changing breed types and introductions provides some evidence of post-productivism and of a multifunctional transition in that several cattle breeds favoured by hobby farmers and boutique breeders are now represented, but the aggregate numbers for these breeds remain small and the numbers for several of the traditional (or colonial) breeds are currently in decline. Overall, it is apparent that Australia's cattle industry retains a strongly productivist ethos and that, particularly given the country's very great environmental variation, its levels of breed diversity remain low

Temperature and trophic structure are driving microbial productivity along a biogeographical gradient

Temperature is known to influence ecosystem processes through its direct effect on biological rates such as respiration and nutrient cycling. These changes can then indirectly affect ecologically processes by altering trophic dynamics, the persistence of a species in a given environment, and, consequently, its distribution. However, it is not known if this direct effect of temperature on biological rates is singularly the most important factor for the functioning of ecosystems, or if trophic structure and the adaptation of a species to the local environment also play an essential role. Understanding the relative importance of these factors is crucial for predicting the impact that climate change will have on species and ecosystems. To achieve a more complete understanding of the impact of changing temperatures, it is necessary to integrate perspectives from biogeography, such as the influences of species distribution and local adaptation, with ecosystem and community ecology. By using the microbial community inhabiting the water-filled leaves of Sarracenia purpurea, we tested the importance of temperature, trophic structure, and local adaptation on ecosystem functioning. We accomplished this by collecting communities along a natural temperature gradient and maintaining these communities in a common garden, factorial experiment. To test for the importance of local adaptation and temperature, the origin of each community was crossed with the temperature from each site. Additionally, to test the importance of top-down trophic regulation for ecosystem functioning, the presence of the mosquito larvae top predator was manipulated. We found that temperature has a greater effect on ecosystem functioning than origin, and that top-down trophic regulation increased with temperature. Our results emphasize the synergistic effects of temperature and biotic interactions when predicting the consequences of global warming on ecosystem functioning