The effect of melatonin on the quality of extended boar semen after long-term storage at 17 °C

Melatonin (MLT) is an efficient antioxidant that protects cells and tissues and initiates a host of receptor-mediated effects. In order to enhance the life span of refrigerated boar semen, our aim was to evaluate the effects of addition of 1 μM MLT to commercially produced pig semen (33 seminal doses from 14 boars) that had been preserved at 17 °C for 7 days. Samples without MLT served as controls. On Days 1, 4 and 7, we evaluated motility parameters and the percentage of total motile and progressively motile spermatozoa by a computer-aided sperm analysis system. Viability (SYBR-14/PI), acrosomal status (FITC-PNA/PI), membrane fluidity (M-540/YoPro-1) and mitochondrial membrane potential status (JC-1) were evaluated by flow cytometry. MLT treatment significantly enhanced the percentage of static spermatozoa after 7 days of storage and significantly reduced the percentage of progressively motile spermatozoa on Day 7. The velocity characteristics (VCL, VSL and VAP) were significantly higher for MLT-treated samples on Day 1 and were their lowest on Day 7. With regard to flow cytometry results, the percentage of viable spermatozoa with an intact acrosome was higher in MLT samples throughout the entire storage period. In addition, there was a significantly higher proportion of live spermatozoa on Day 7 in the samples that had not been treated with MLT. The proportion of spermatozoa showing a high mitochondrial membrane potential remained at similar levels (P > 0.05) throughout the trial. Although the findings of the present study revealed that 1 μM MLT increased the proportion of live sperm with an intact acrosome, this treatment did not enhance the spermatic quality of refrigerated boar semen.     

Effects of green tea polyphenol on the quality of canine semen after long-term storage at 5 °C

The aim of the present study was to determine the effects of green tea polyphenol on the quality of canine semen after long-term storage at 5 °C. The supplementation of a Tris-egg yolk extender with polyphenol (0.5, 0.75, or 1 mg/mL) increased the motility and viability of sperm preserved for four weeks at 5 °C.     

Is the relationship between fertility of parents and children really weak?

The relationship between fertility of parents and children has been designated as "weak" by most investigators. This paper reviews the evidence over the past century and argues that, even allowing for problems with available data sources, the relationship was probably close to zero for pre-transitional populations. However, over time, the relationship has tended to become more substantial and is now of a similar order of magnitude in developed countries as other widely used explanatory variables. Possible mechanisms for the observed relationship are discussed, especially the roles of socialization and inherited factors. The types of data used are compared to the scientific questions posed, and the limitations of the common comparison of married-mother/married-daughter pairs are considered. Finally, some evidence from recent large-scale surveys in Britain and the United States is presented to show changes over recent periods and the relative effects of sibship size of fathers and mothers.     

Intensity-dependent effects of cattle and sheep grazing in sand grasslands — Does livestock type really matter?

Aims

By analysing cattle- and sheep-grazed sand grasslands, we tested the following hypotheses: (i) livestock type has a stronger effect on the vegetation characteristics than grazing intensity; (ii) sheep grazing results in lower biomass and species and functional diversity than cattle grazing, regardless of intensity; and (iii) increased grazing intensity causes a shift of the trait composition in grasslands.

Location

Sand grasslands in the Nyírség region, East Hungary.

Methods

We selected 26 sand grassland sites grazed by cattle or sheep and classified them into four intensity levels. Vegetation composition was surveyed in 2 m × 2 m plots. We harvested the above-ground biomass from 20 cm × 20 cm plots; then dried and sorted it to live biomass, litter, moss, and lichen. We compared Rao dissimilarity index, species richness, Shannon diversity, evenness, and the community-weighted means of nine vegetative and generative traits along a grazing intensity gradient. We calculated functional richness, evenness, and divergence for comparison.

Results

We found that some diversity metrics and community-weighted means of most studied traits were significantly affected by grazing intensity. Several characteristics were also affected by the interaction of grazing intensity and livestock type, but none of the studied characteristics was affected by livestock type in itself. Increasing Rao dissimilarity index peaking at the fourth grazing intensity level was detected, but for other multitrait indices, no such changes were proven, except for functional divergence, which was the lowest at the first intensity level. Graminoid, forb, and litter biomass were significantly affected by intensity, but none of the biomass fractions was affected by livestock type.

Conclusions

We suggest that for the management of sand grasslands, grazing intensity should be carefully adjusted, considering not only livestock units per hectare. For practical recommendations, well-defined, long-term experiments studying different livestock and habitat types along an intensity gradient would be essential.     

Effect of the holding time at 15 °C prior to cryopreservation,the thawing rate and the post-thaw incubation temperature on the boar sperm quality after cryopreservation

The aim of the present study was to evaluate the effect of the holding time at 15 °C prior to cryopreservation (2, 4 and 8 h), thawing rate (37 °C for 20 s or 70 °C for 8 s) and post-thaw incubation temperature (15 °C or 37 °C) on the post-thaw boar sperm quality. These are important time periods in the freezing–thawing process which have been less studied. Sperm-rich ejaculate fractions from three healthy boars were collected once a week for five consecutive weeks and were cryopreserved with the lactose-egg yolk extender (LEY). Sperm quality was determined by assessing the motility, the acrosome status, and the sperm plasma membrane integrity at 30, 150 and 240 min of incubation. The results show that with the holding time at 15 °C prior to cryopreservation there was not a clear effect until at least 24 h of holding time. The thawing rate and the post-thaw incubation temperature, however, had a marked effect on sperm quality. When the samples were thawed at 70 °C for 8 s, the sperm viability, motility and some kinetic variables (VCL, VSL, VAP and ALH) were greater than with results observed when the samples were thawed at 37 °C for 20 s. In addition after thawing the sperm samples incubated at 15 °C had a sustained sperm quality for longer, up to 4 h post-thawing.     

Responses of nitrification and denitrification to nitrogen and phosphorus fertilization: does the intrinsic soil fertility matter?

Plant and Soil - Nitrogen (N) is not only a major regulator of productivity in terrestrial systems but can also be a pollutant. While the effects of fertilizer addition to soil N cycling processes...     

Staffing levels in not-for-profit and for-profit long-term care facilities: Does type of ownership matter?

Background

Currently there is a lot of debate about the advantages and disadvantages of for-profit health care delivery. We examined staffing ratios for direct-care and support staff in publicly funded not-for-profit and for-profit nursing homes in British Columbia.

Methods

We obtained staffing data for 167 long-term care facilities and linked these to the type of facility and ownership of the facility. All staff were members of the same bargaining association and received identical wages in both not-for-profit and for-profit facilities. Similar public funding is provided to both types of facilities, although the amounts vary by the level of functional dependence of the residents. We compared the mean number of hours per resident-day provided by direct-care staff (registered nurses, licensed practical nurses and resident care aides) and support staff (housekeeping, dietary and laundry staff) in not-for-profit versus for-profit facilities, after adjusting for facility size (number of beds) and level of care.

Results

The nursing homes included in our study comprised 76% of all such facilities in the province. Of the 167 nursing homes examined, 109 (65%) were not-for-profit and 58 (35%) were for-profit; 24% of the for-profit homes were part of a chain, and the remaining homes were owned by a single operator. The mean number of hours per resident-day was higher in the not-for-profit facilities than in the for-profit facilities for both direct-care and support staff and for all facility levels of care. Compared with for-profit ownership, not-for-profit status was associated with an estimated 0.34 more hours per resident-day (95% confidence interval [CI] 0.18–0.49, p < 0.001) provided by direct-care staff and 0.23 more hours per resident-day (95% CI 0.15–0.30, p < 0.001) provided by support staff.

Interpretation

Not-for-profit facility ownership is associated with higher staffing levels. This finding suggests that public money used to provide care to frail eldery people purchases significantly fewer direct-care and support staff hours per resident-day in for-profit long-term care facilities than in not-for-profit facilities.Nnursing homes provide long-term housing, support and direct care to members of the community who are unable to function independently because of medical, physical and cognitive disabilities. Although only a small proportion of older Canadians reside in nursing homes (18% of those ≥ 80 years), the majority (81%) of long-term care residents are frail elderly people over the age of 65.¹Government-funded long-term care in Canada has been provided for many years by a mix of not-for-profit (nonproprietary) and for-profit (proprietary) facilities. The ratio of this mix varies greatly by province. For example, in Ontario 52% of publicly funded nursing homes are for-profit, as compared with 15% in Manitoba.²Previous studies from the United States have shown that having more direct-care personnel is associated with better care in nursing homes.^3,4,5,6,7 Specifically, higher numbers of registered-nurse hours per resident-day have been associated with fewer violations of care standards⁴ and improved functional ability of residents.⁷ Schnelle and colleagues examined 21 nursing homes in California and found that the homes with the highest number of nurse aides performed significantly better in 13 of 16 quality-of-care measures than the homes with fewer nurse aides.⁶ Although there has been little research on staffing levels and nursing home care in other countries, health policy-makers in the United Kingdom⁸ and Australia⁹ have begun to call for greater accountability for public resources spent in this area.The American literature has also shown that, compared with for-profit nursing homes, not-for-profit facilities have higher direct-care staffing levels⁴ and lower staff turnover rates.^10,11 However, the majority of nursing home care in the United States is delivered by the for-profit sector, whereas in Canada the not-for-profit sector constitutes the majority. This may result in a difference in the informal benchmarks for staffing levels between the 2 countries. There also may be a wider variation in wages and working conditions among nursing homes in the United States, which potentially confounds the comparison between for-profit and not-for-profit facilities.We compared staffing levels of nursing and support staff in publicly funded long-term care facilities by ownership type (not-for-profit v. for-profit) in British Columbia at a time when the majority of publicly funded not-for-profit and for-profit facilities employed a unionized labour force with standardized wages and benefits set by a master collective agreement.In British Columbia, approximately 70% of publicly funded nursing homes are nonproprietary (not-for-profit) and 30% are proprietary (for-profit). Both not-for-profit and for-profit facilities receive global funding from the provincial government on the basis of (a) the level of functional dependence of facility residents and (b) the percentage of fees borne by residents according to their income levels. At the time of the study (2001), there was no regulation by government or the regional health authorities as to how individual facilities allocated funding between staffing, administration or property costs.Not-for-profit long-term care in British Columbia is delivered by religious, cultural or other community-based societies, by regional health authorities or by publicly owned acute care hospitals. For-profit care is delivered by sole operators or by facilities that are part of larger business entities (chains). Nursing homes are grouped by levels of care according to the residents'' case-mix: intermediate care only (IC), intermediate and extended care (IC & EC), multi-level care, or extended care only. IC facilities provide care for people with relatively more functional ability, whereas extended care facilities accommodate the most functionally dependent people. The other 2 facility types provide care for people with a mix of functional abilities.     

The continuity of living matter and the discontinuities of its constituents: do plankton and benthos really exist?

Plankton and benthos are popular concepts identifying two ways of life of aquatic organisms. Their spatial separation led to the development of different sampling techniques and to separate conceptualizations of the principles governing these subsets of the aquatic environment. Reciprocal connections between plankton and benthos, however, are very strong both from a functional (energy fluxes) and a structural (life cycle dynamics) point of view. A full appreciation of such links is forcing marine ecology towards a more integrated approach.     

Response of the ArcCHECK® device at 6 MV and 15 MV for VMAT and IMRT quality control

PurposeTo study the response of the ArcCHECK® device as VMAT and IMRT verification system.MethodsVarious tests analyzing the linearity, the repeatability and the angular dependence of the device response, its dependence with the pulse repetition rate and the leakage losses were performed. The long-term response in dose measurements and the uniformity of the detectors conforming the system were controlled using a statistical process control program. The Elekta Infinity™ 6 and 15 MV photon beams were used.ResultsThe device showed excellent repeatability and linearity. The differences between the responses obtained for any pair of angular incidences were less than 2%. The absorbed dose increased by 3% when the pulse repetition rate varied from 50 to 600 MU/min. Results are in overall agreement with those found in previous works for the ArcCHECK®, in which a reduced number of the device diodes were analyzed, and for the MapCheck®, an older 2D device that used the same diodes. Charge losses were found to be negligible except for some of the diodes of the device. The statistical process control program is a very useful tool to control the correct functioning of the device in the long term.ConclusionsThe results of the analysis carried out indicate that the working and stability conditions of the ArcCHECK® device are adequate for its purpose. The dependence with the pulse repetition rate should be considered when VMAT or similar treatments are evaluated. A control program for the statistical monitoring of the device would be desirable and useful.     

Cadherins and the cortex: A matter of time?

Cell adhesion systems commonly operate in close partnership with the cytoskeleton. Adhesion receptors bind to the cortex and regulate its dynamics, organization and mechanics; conversely, the cytoskeleton influences aspects of adhesion, including strength, stability and ductility. In this review we consider recent advances in elucidating such cooperation, focusing on interactions between classical cadherins and actomyosin. The evidence presents an apparent paradox. Molecular mechanisms of mechanosensation by the cadherin-actin apparatus imply that adhesion strengthens under tension. However, this does not always translate to the broader setting of confluent tissues, where increases in fluctuations of tension can promote intercalation due to the shrinkage of adherens junctions. Emerging evidence suggests that understanding of timescales may be important in resolving this issue, but that further work is needed to understand the role of adhesive strengthening across scales.     

What is the matter with transcendence? On the place of religion in the new anthropology of ethics★

A focus on ordinary or everyday ethics has become perhaps the dominant concern in the rapidly developing anthropology of ethics. In this article, I argue that this focus tends to marginalize the study of the ways in which religion contributes to people's moral lives. After defining religion and transcendence in terms that make them less uncongenial to the study of ethics than many proponents of ordinary ethics suggest, I examine values as one sometimes transcendent cultural form that often informs ethical life. I draw on Victor Turner (along with Durkheim) to develop an account of how rituals often both present people with and allow them to perform transcendent versions of values. These encounters, in turn, shape people's ethical sensibilities, including those they bring to bear in everyday life, in ways we cannot understand unless we accord religion a more central role in the anthropology of ethics than it has played to this point. I illustrate my arguments with material drawn both from Turner's Ndembu ethnography and from my own research on Christianity in Papua New Guinea.     

Does climate change influence the availability and quality of reindeer forage plants?

The northward and upward movement of the tree line and gradual replacement of lichens with vascular plants associated with increasing temperatures and nutrient availability may change the reindeer pastures in Northern Fennoscandia. The productivity of reindeer forage will most probably increase, but their protein (nitrogen) concentrations may decrease because of higher temperatures and CO₂ concentration. In the long term, the nutritive value of forage will depend on the mineralization rate and nutrient uptake from the soil. Enhanced UV-B is likely to increase the concentration of phenolics, decreasing forage quality and choice, but reindeer may adapt to increased phenolics. Increased winter precipitation, the occurrence of ice layers, deeper snow cover, and the appearance of molds beneath the snow cover may reduce the availability and/or quality of reindeer forage, but prolongation of snowless periods might have the opposite effect. The net balance of negative and positive effects will vary regionally depending on the climate, bedrock, vegetation, reindeer herding systems and socio-political factors. Multidisciplinary research is needed most importantly on the effects of the changing winter climate on reindeer forage, and the effect of modified forage quality on reindeer physiology.

Does detritus quality predict the effect of native and non‐native plants on the performance of larval amphibians?

1. The lack of consistent differences between the traits of native and non‐native plant species makes it difficult to make general predictions about the ecological impact of invasive plants; however, the increasing number of non‐native plants in many habitats makes the assessment of the impact of each individual species impracticable. General knowledge about how specific plant traits are linked to their effects on communities or ecosystems may be more useful for predicting the effect of plant invasions. Specifically, we hypothesised that higher carbon‐to‐nitrogen ratio (C:N) and percent lignin in plant detritus would reduce the rate of development and total mass at metamorphosis of tadpoles, resulting in lower metamorph production (total fresh biomass) and amphibian species richness. 2. To test these hypotheses, we raised five species of tadpoles in mesocosms containing senescent leaves of three common native and three common non‐native wetland plants that varied in C:N ratio and % lignin. 3. Leaf mass loss, total metamorph production and the number of species that metamorphosed declined as a function of increasing C:N ratio of plant leaves. Plant lignin content was not related to the production of metamorphs or the number of species that metamorphosed. The percentage of wood frog (Lithobates sylvaticus) and American toad (Anaxyrus americanus) tadpoles reaching metamorphosis declined as a function of increasing plant C:N ratio. Mean time to metamorphosis increased and mean mass at metamorphosis declined as a function of increasing plant C:N ratio. Tadpole performance and metamorph diversity and production (biomass) were similar between native and non‐native plant species with similar C:N ratio in leaves. Percent lignin was not a significant predictor of tadpole performance. 4. Our results show that the impact of a plant invasion on tadpole performance could depend on differences between the quality of the detritus produced by the invading species and that of the native species it replaces. We suggest that plant community changes that lead to dominance by more recalcitrant plant species (those with higher leaf C:N ratio) may negatively affect amphibian populations.     

Developmental programming of reproduction and fertility: what is the evidence?

The concept of the foetal/developmental origins of adult disease has been around for ~20 years and from the original epidemiological studies in human populations much more evidence has accumulated from the many studies in animal models. The majority of these have focused upon the role of early dietary intake before conception, through gestation and/or lactation and subsequent interactions with the postnatal environment, e.g. dietary and physical activity exposures. Whilst a number of theoretical models have been proposed to place the experimental data into a biological context, the underlying phenomena remain the same; developmental deficits (of single (micro) nutrients) during critical or sensitive periods of tissue growth alter the developmental pathway to ultimately constrain later functional capacity when the individual is adult. Ageing, without exception, exacerbates any programmed sequelae. Thus, adult phenotypes that have been relatively easy to characterise (e.g. blood pressure, insulin sensitivity, body fat mass) have received most attention in the literature. To date, relatively few studies have considered the effect of differential early environmental exposures on reproductive function and fecundity in predominantly mono-ovular species such as the sheep, cow and human. The available evidence suggests that prenatal insults, undernutrition for example, have little effect on lifetime reproductive capacity despite subtle effects on the hypothalamic-pituitary-gonadal axis and gonadal progenitor cell complement. The postnatal environment is clearly important, however, since neonatal/adolescent growth acceleration (itself not independent from prenatal experience) has been shown to significantly influence fecundity in farm animals. The present paper will expand these interesting areas of investigation and review the available evidence regarding developmental programming of reproduction and fertility. However, it appears there is little strong evidence to indicate that offspring fertility and reproductive senescence in the human and in farm animal species are overtly affected by prenatal nutrient exposure. Nevertheless, it is clear that the developing gonad is sensitive to its immediate environment but more detailed investigation is required to specifically test the long-term consequences of nutritional perturbations during pregnancy on adult reproductive well-being.     

Fledging success of little auks in the high Arctic: do provisioning rates and the quality of foraging grounds matter?

Long-lived birds often face a dilemma between self-maintenance and reproduction. In order to maximize fitness, some seabird parents alternate short trips to collect food for offspring with long trips for self-feeding (bimodal foraging strategy). In this study, we examined whether temporal and spatial variation in the quality of foraging grounds affect provisioning and fledging success of a long-lived, bimodal forager, the little auk (Alle alle), the most abundant seabird species in the Arctic ecosystem. We predicted that an increase in sea surface temperature (SST), with an associated decrease in the preferred Arctic zooplankton prey, would increase foraging trip durations, decrease chick provisioning rates and decrease chick fledging success. Chick provisioning and survival were observed during three consecutive years (2008–2010) at two colonies with variable foraging conditions in Spitsbergen: Isfjorden and Magdalenefjorden. We found that a change in SST (range 1.6–5.4 °C) did not influence trip durations or provisioning rates. SST was, however, negatively correlated with the number of prey items delivered to a chick. Furthermore, provisioning rates did not influence chick’s probability to fledge; instead, SST was also negatively correlated with fledging probability. This was likely related to the prey availability and quality in the little auk’s foraging grounds. Our findings suggest that predicted warmer climate in the Arctic will negatively influence the ability of parents to provide their chicks, and consequently, the fledging prospects of little auk chicks.