DNA from soil mirrors plant taxonomic and growth form diversity.

Ecosystems across the globe are threatened by climate change and human activities. New rapid survey approaches for monitoring biodiversity would greatly advance assessment and understanding of these threats. Taking advantage of next-generation DNA sequencing, we tested an approach we call metabarcoding: high-throughput and simultaneous taxa identification based on a very short (usually <100 base pairs) but informative DNA fragment. Short DNA fragments allow the use of degraded DNA from environmental samples. All analyses included amplification using plant-specific versatile primers, sequencing and estimation of taxonomic diversity. We tested in three steps whether degraded DNA from dead material in soil has the potential of efficiently assessing biodiversity in different biomes. First, soil DNA from eight boreal plant communities located in two different vegetation types (meadow and heath) was amplified. Plant diversity detected from boreal soil was highly consistent with plant taxonomic and growth form diversity estimated from conventional above-ground surveys. Second, we assessed DNA persistence using samples from formerly cultivated soils in temperate environments. We found that the number of crop DNA sequences retrieved strongly varied with years since last cultivation, and crop sequences were absent from nearby, uncultivated plots. Third, we assessed the universal applicability of DNA metabarcoding using soil samples from tropical environments: a large proportion of species and families from the study site were efficiently recovered. The results open unprecedented opportunities for large-scale DNA-based biodiversity studies across a range of taxonomic groups using standardized metabarcoding approaches.

Wildfire responses to abrupt climate change in North America.

It is widely accepted, based on data from the last few decades and on model simulations, that anthropogenic climate change will cause increased fire activity. However, less attention has been paid to the relationship between abrupt climate changes and heightened fire activity in the paleorecord. We use 35 charcoal and pollen records to assess how fire regimes in North America changed during the last glacial-interglacial transition (15 to 10 ka), a time of large and rapid climate changes. We also test the hypothesis that a comet impact initiated continental-scale wildfires at 12.9 ka; the data do not support this idea, nor are continent-wide fires indicated at any time during deglaciation. There are, however, clear links between large climate changes and fire activity. Biomass burning gradually increased from the glacial period to the beginning of the Younger Dryas. Although there are changes in biomass burning during the Younger Dryas, there is no systematic trend. There is a further increase in biomass burning after the Younger Dryas. Intervals of rapid climate change at 13.9, 13.2, and 11.7 ka are marked by large increases in fire activity. The timing of changes in fire is not coincident with changes in human population density or the timing of the extinction of the megafauna. Although these factors could have contributed to fire-regime changes at individual sites or at specific times, the charcoal data indicate an important role for climate, and particularly rapid climate change, in determining broad-scale levels of fire activity.

Persistence of arctic-alpine flora during 24,000 years of environmental change in the Polar Urals.

Plants adapted to extreme conditions can be at high risk from climate change; arctic-alpine plants, in particular, could "run out of space" as they are out-competed by expansion of woody vegetation. Mountain regions could potentially provide safe sites for arctic-alpine plants in a warmer climate, but empirical evidence is fragmentary. Here we present a 24,000-year record of species persistence based on sedimentary ancient DNA (sedaDNA) from Lake Bolshoye Shchuchye (Polar Urals). We provide robust evidence of long-term persistence of arctic-alpine plants through large-magnitude climate changes but document a decline in their diversity during a past expansion of woody vegetation. Nevertheless, most of the plants that were present during the last glacial interval, including all of the arctic-alpines, are still found in the region today. This underlines the conservation significance of mountain landscapes via their provision of a range of habitats that confer resilience to climate change, particularly for arctic-alpine taxa.

Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield.

How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture.

Breastfeeding initiation: An in-depth qualitative analysis of the perspectives of women and midwives using Social Cognitive Theory.

OBJECTIVE: to explore women's and midwives' expectations, knowledge and experiences of breastfeeding initiation using Social Cognitive Theory. DESIGN: a qualitative study using focus group discussions and individual interviews. Breastfeeding initiation was defined for this study as a process within the first 48hours after birth. Data were analysed using qualitative inductive analysis then further deductive analysis using Social Cognitive Theory (SCT). SETTING AND PARTICIPANTS: a purposefully selected sample of primigravid antenatal and postnatal women (n=18) and practising midwives (n=18) from one Health Board area in Scotland. FINDINGS: attachment of the baby to the breast at birth was hindered by sleepy babies and the busy unfamiliar hospital environment. These resulted in mothers struggling to maintain their motivation to breastfeed and to develop low self-efficacy. Instinctive attachment was rare. Midwives who considered it was normal for babies to be sleepy and unable to attach or feed at birth did not facilitate instinctive baby behaviour. Midwives sometimes experienced lack of autonomy and environmental circumstances that made women centred care difficult. Furthermore caring for high numbers of women, dependent on their help, resulted in reduced self-efficacy for providing effective breastfeeding support. KEY CONCLUSIONS: interviewing both women and midwives specifically about initiation of breastfeeding has allowed for deeper insights into this critical period and enabled a comparison between the data obtained from mothers and midwives. The findings suggest that instinctive attachment is not an expectation of either mothers or midwives and results in a loss of breastfeeding confidence in both. IMPLICATIONS FOR PRACTICE: to facilitate initiation there is a need for more research to develop appropriate maternal and midwifery skills, and make changes to the cultural environment in hospitals. Social Cognitive Theory could be used as a framework in both the antenatal and immediate postnatal period to develop strategies and materials to increase women's and midwives' self-efficacy specifically in initiation.

Improvement in the health-related quality-of-life symptoms of hyperparathyroidism is durable on long-term follow-up.

BACKGROUND: Subjective symptoms such as decreased energy, chronic fatigue, and depression are associated with hyperparathyroidism. Studies have shown that these symptoms are improved during short-term follow-up after parathyroidectomy. This study evaluates the durability of this subjective improvement in quality-of-life symptoms in a large population of patients with follow-up greater than 1 year after operation. METHODS: Between 2002 and 2005, 258 patients underwent parathyroidectomy, 100 (81 females and 19 males) of whom were available for this study. The patients were evaluated with a survey based on the Health Outcomes Institute Health Status Questionnaire. Some answers were quantified on a 1 to 6 scale, while others consisted of "yes" or "no" responses. Patients completed a questionnaire prior to parathyroidectomy and postoperatively at 1 month, 3 to 6 months, and 1 to 2 years or greater intervals. Statistical analysis was used to detect changes attributable to parathyroidectomy. A P value <.05 was considered statistically significant. RESULTS: At 1-month follow-up, patients' perceptions of their overall health, energy level, and mood significantly improved. At 6-month follow-up, significant improvements in muscle strength, health, endurance, and relief of anxiety were documented. At the interval of 1 to 2 years, overall health, energy level, endurance, and relief of anxiety were improved. There was no significant decrement in the quality of life in these patients after parathyroidectomy. CONCLUSIONS: Parathyroidectomy for hyperparathyroidism is associated with significant lasting improvement in subjective symptoms. The potential durable improvement in these quality-of-life symptoms is a valid indication for parathyroidectomy.

Pathogenesis of an unexpected sudden death: role of early cycle ventricular premature contractions.

A 61 year old man who had been studied extensively died unexpectedly ("instantaneously") outside the hospital while wearing an electrocardiographic recorder. Death was caused by ventricular fibrillation, which was initiated by an early cycle ventricular premature contraction occurring in the vulnerable period of repolarization. Such early cycle ventricular premature contraction had been noted in recordings 4 years previously but had never been observed to encroach on the T wave until 5 minutes before death. In the intervening period, the patient had shown increasing evidence of myocardial ischemia and hypertrophy and congestive heart failure, which had been partly obscured by his concealment or denial of symptoms and refusal to change his pattern of activities. Autopsy revealed two old myocardial infarcts and pronounced left ventricular hypertrophy. There was advanced occlusive arteriosclerosis of the major coronary vessels with a recent thrombus in the right coronary artery.

Role of viscoelastic properties of differentiated SH-SY5Y human neuroblastoma cells in cyclic shear stress injury.

Shear stress and strain lead to neurodegeneration in vivo during head injury, glaucoma, and certain repetitive motion disorders. In vitro, shear stress and strain have been shown to lead to cell injury in a number of models using neurons and neuron-like cells. In the present study we examined the relationship between shear stress, strain, and the extent of cell injury in a cyclic shear stress induced model of cell injury using differentiated SH-SY5Y (human neuroblastoma) cells. Shear stress led to cell strain that increased with increasing stress and diminished upon cessation of shear. Strain rate during cyclic application of shear stress increased by over an order of magnitude from the first to all subsequent cycles, suggesting that the cell and/or its polymer network became more elastic upon cyclic shear stress application. To support this conclusion we measured the degree of cytoskeletal polymerization before and after exposure of cells to cyclic shear stress and found that the fraction of polymerized tubulin in the cell relative to total tubulin decreased by a factor of 2 after six cycles of shear stress. The extent of injury, as indicated by the fraction of cells with fragmented DNA, was three times higher for cyclic shear stress than for steady shear stress and may be related to the change in strain rate and/or cytoskeletal reorganization associated with cyclic stress. These findings may aid in understanding the mechanism by which neurons and neuron-like cells respond to cyclic shear stress and strain and lead to new treatments for disease or injury arising from the exposure of neurons to abnormal cyclic or repetitive stress and strain.

Psychophysiological factors in ventricular arrhythmias and sudden cardiac death.

Plasma catecholamine levels were measured preceding programmed electrophysiological studies of patients who had survived a ventricular tachyarrhythmia episode. Psychological assessments of desire for control, locus of control and behavior pattern were obtained. Psychophysiological variables were analysed with respect to the severity of arrhythmias induced by the electrophysiological procedure. Analysis of data from 17 subjects showed desire for control was significantly higher in those with induced sustained arrhythmias than in those in which nonsustained arrhythmias were induced. No relationship was found between behavior pattern and arrhythmia severity or plasma catecholamine levels. There was a significant interaction between desire for control and behavior pattern with respect to epinephrine level. The findings indicate that psychological factors such as desire for control may be associated with potentially lethal arrhythmias and implicated in sudden cardiac death.

Use of a mathematical model to estimate stress and strain during elevated pressure induced lamina cribrosa deformation.

BACKGROUND: High intraocular pressure (IOP), which is generally associated with glaucoma, causes lamina cribrosa retrodisplacement and deformation. Shear stress and strain resulting from lamina cribrosa deformation have been implicated in tissue remodeling, changes in retinal astrocyte function and retinal ganglion cell (RGC) death observed in vivo during glaucoma. METHODS: A mathematical model was developed to describe the lamina cribrosa exposed to elevated intraocular pressure (IOP). The model is based on the bending theory of plates, incorporates anatomical properties of the lamina cribrosa, and provides estimates of its biomechanical properties. The model relates IOP, the parameter normally correlated with glaucoma, and lamina cribrosa retrodisplacement to stress and strain experienced by cells, parameters that may be more closely associated with cell injury. RESULTS: We estimate that shear strains of 0.05 occur at the edge of a 200 microm thick lamina cribrosa at an IOP of 25 mm Hg. We estimate greater lamina cribrosa deformation and higher shear stress and strain for thinner lamina cribrosa and lamina cribrosa of larger radii. CONCLUSION: These results may provide better estimates of the stress and strain experienced by cells in the lamina cribrosa and may further our understanding of the forces that contribute to optic nerve degeneration during glaucoma.

Oral lavage with polyethylene glycol reduces microbial colonization in the gastrointestinal tract of broilers.

Oral lavage of 7-wk-old broiler chickens with polyethylene glycol (PEG) was conducted to induce rapid evacuation of the gastro-intestinal tract (GIT) before processing. Three groups of birds were fed ad libitum (FF), subjected to feed withdrawal 12 h before processing (FW), or received 115 mL of PEG by oral lavage 3 h before processing (PEG(L)). The crop, a section of small intestine, and the right cecum were aseptically collected for determination of contents and Gram-negative bacilli (GNB) counts. The PEG(L) effectively cleansed the upper GIT and intestine of treated birds within 3 h before processing. However, the ceca were not completely empty for all the birds subjected to PEG(L). The PEG(L) group had a significantly lower crop and cecal GNB concentrations than the FW group. Birds on FW and PEG(L) treatments had significantly lower GNB concentrations in the small intestine than FF birds. Polyethylene glycol resulted in complete evacuation of the upper GIT, as well as the intestine, within 3 h of use, and significantly reduced GNB concentrations.

Ocular inserts for application of drugs to bovine eyes--in vitro studies on gentamicin release from collagen inserts.

Soluble collagen and insoluble collagen films were impregnated with gentamicin and investigated in vitro as vehicles for the delivery drugs. Succinylated collagen released significantly higher levels of antibiotic than the insoluble films, and maintained mean inhibitory concentrations (MIC) for Moraxella bovis for 24 h.

A national survey of the occurrence of infectious bovine keratoconjunctivitis.

A national mail survey of 4880 beef and dairy producers was undertaken to record details of infectious bovine keratoconjunctivitis. One thousand four hundred and fifty eight (29.8%) questionnaires were returned. The survey confirmed the widespread nature of the disease with higher prevalence in the summer months, in calves and dairy cattle, and in Bos taurus breeds. The constant prevalence contrasts with the disease in New Zealand where it is increasing.

A national survey of the clinical features, treatment and importance of infectious bovine keratoconjunctivitis.

A postal survey of cattle producers throughout Australia was conducted to obtain information concerning the occurrence, signs and treatment of infectious bovine keratocojunctivitis, animals breeds, animal numbers and types, environmental conditions under which the animals were kept and management routines and systems of the animals (Slatter et al 1982). The most common clinical signs reported were ocular discharge (43.9%), corneal opacity (9.9%), or both (46.1%). The majority of respondents (54.8%) indicated duration of infections of at least 3 weeks. The condition was predominantly unilateral (74.7%) but 22.3% of respondents reported an equal occurrence of the condition unilaterally and bilaterally. The most frequently used drugs were homidium bromide (26.7%), oxytetracycline hydrochloride (22.8%), chloramphenicol derivatives (13.7%) and penicillin derivatives (13.5%). However, described treatment regimes indicated that therapeutic levels of antibiotics would not be maintained in the eyes of treated animals. Producers considered that 75% of affected animals showed reduced rates of weight gain, and 64% indicated they were more difficult to handle. An approximate figure of +22,000,000 was determined for loss of national production due to the disease, based on producers' estimates. In addition, a further cost of +1,566,500 was estimated for the labour involved in current treatment regimes. Beef and dairy producers spent different amounts on medications and treated for different durations. The economic significance of the disease justifies further studies on production losses due to the disease and cost effective methods of treatment.

Thermokarst lakes as a source of atmospheric CH4 during the last deglaciation.

Polar ice-core records suggest that an arctic or boreal source was responsible for more than 30% of the large increase in global atmospheric methane (CH4) concentration during deglacial climate warming; however, specific sources of that CH4 are still debated. Here we present an estimate of past CH4 flux during deglaciation from bubbling from thermokarst (thaw) lakes. Based on high rates of CH4 bubbling from contemporary arctic thermokarst lakes, high CH4 production potentials of organic matter from Pleistocene-aged frozen sediments, and estimates of the changing extent of these deposits as thermokarst lakes developed during deglaciation, we find that CH4 bubbling from newly forming thermokarst lakes comprised 33 to 87% of the high-latitude increase in atmospheric methane concentration and, in turn, contributed to the climate warming at the Pleistocene-Holocene transition.