Elevated Carbon Dioxide and Litter Decomposition in California Annual Grasslands: Which Mechanisms Matter?

To date, most research that has examined the effect of elevated atmospheric carbon dioxide concentration ([CO₂]) on litter decomposition has focused on changes in the leaf litter quality of individual species. Results from California grasslands indicate that other CO₂ responses may have greater consequences for decomposition rates. For instance, CO₂-driven changes in either species dominance or patterns of biomass allocation would alter both the quality and the position of grassland litter. We review the results from studies in California grasslands to identify the mechanisms that affect grassland litter decomposition. We use a simple calculation that integrates the results of two studies to identify three mechanisms that have the potential to substantially alter decomposition rates as the atmospheric [CO₂] rises. Received 16 January 2001; accepted 26 September 2001.     

Relation Between Personality and Ventilatory Response to Carbon Dioxide in Normal Subjects: A Role in Asthma?

Ventilatory response to carbon dioxide, as an index of respiratory centre sensitivity, was measured in 50 normal subjects. Their personality was documented in terms of extraversion and neuroticism scores by the Eysenck Personality Inventory. A significant correlation was found between extraversion score and ventilatory response to carbon dioxide in women (P < 0·005) but not in men. No correlation was found between ventilatory responsiveness and neuroticism score in either sex. It is suggested that the degree of extraversion may play some part in determining the level of ventilation adopted, and hence of arterial carbon dioxide tension, if and when women develop lung disease such as asthma.     

What counts? Volunteers and their organisations in the recording and monitoring of biodiversity

There is a pressing need for volunteer amateur naturalists to participate in data collection for biodiversity monitoring programmes in Europe. It is being addressed in some countries, but less so in others. This paper discusses the results from qualitative research using semi-structured interviews, focus groups and participant observation within nine Participatory Monitoring Network (PMN) organisations in six European countries. The paper examines the features that facilitate recruitment, retention and motivations of volunteers to participate in biodiversity monitoring, including the social and cultural milieus in which they operate. The paper concludes that volunteers place a high degree of significance on their social experience within PMNs. Successful creation and management of PMNs thus requires that similar levels of attention be paid to social aspects of the organisation as are paid to the generation and management of data.     

Mesenchymal stem cells and their use in therapy: What has been achieved?

The considerable therapeutic potential of human multipotent mesenchymal stromal cells or mesenchymal stem cells (MSCs) has generated increasing interest in a wide variety of biomedical disciplines. Nevertheless, researchers report studies on MSCs using different methods of isolation and expansion, as well as different approaches to characterize them; therefore, it is increasingly difficult to compare and contrast study outcomes. To begin to address this issue, the Mesenchymal and Tissue Stem Cell Committee of the International Society for Cellular Therapy proposed minimal criteria to define human MSCs. First, MSCs must be plastic-adherent when maintained in standard culture conditions (α minimal essential medium plus 20% fetal bovine serum). Second, MSCs must express CD105, CD73 and CD90, and MSCs must lack expression of CD45, CD34, CD14 or CD11b, CD79α or CD19 and HLA-DR surface molecules. Third, MSCs must differentiate into osteoblasts, adipocytes and chondroblasts in vitro. MSCs are isolated from many adult tissues, in particular from bone marrow and adipose tissue. Along with their capacity to differentiate and transdifferentiate into cells of different lineages, these cells have also generated great interest for their ability to display immunomodulatory capacities. Indeed, a major breakthrough was the finding that MSCs are able to induce peripheral tolerance, suggesting that they may be used as therapeutic tools in immune-mediated disorders. Although no significant adverse events have been reported in clinical trials to date, all interventional therapies have some inherent risks. Potential risks for undesirable events, such as tumor development, that might occur while using these stem cells for therapy must be taken into account and contrasted against the potential benefits to patients.     

Top predator fish assemblages in Northern Patagonia,Argentina. What factors regulate their patterns of distribution and abundance?

According to assemblage theory, three factors regulate fish biogeography: restriction of dispersion, environmental restrictions and biotic interactions. The first two factors act on a regional scale and delimit the area of action of the third, which operates on a local scale. Salmonid introductions began in Patagonia in 1904, and this has led to a restructuring of trophic webs and an increase in the number of top predators. This situation allowed us to evaluate, in a natural setting, how communities are formed on different geographic scales. We studied two large basins in Patagonia, situated close to each other but with different assemblages of top predatory fish. We hypothesized that differences in the structuring of the top predator assemblages between and within the basins are due to 1) environmental factors and dispersion processes facilitated by connectivity on a regional scale; and 2) biotic interaction (internal dynamics) between native perch and salmonids, the former acting as a modulator of the top predator assemblages on a local scale. To test these hypotheses, we analysed the top predator assemblages of 16 lakes and one reservoir, as well as their environmental characteristics. We performed a cluster analysis and related the resulting assembly groups to environmental factors by means of a tree model. We also analysed fish diets, using a similarities test to study biotic interactions. On regional and local scales, water basin, degree of connectivity, area, temperature and Zoogeographic integrity coefficient (ZIC) were important factors in the structuring of top predator assemblages. On a local scale, creole perch modulates the salmonid populations through feeding and the consequent distribution of resources. Our work showed that the structure of top predator assemblages was determined by a combination of local and regional factors acting in synergy, as postulated by the assemblage theory.     

The polyphenolic content of fruit and vegetables and their antioxidant activities. What does a serving constitute?

Analysis of the major flavone, flavonol, anthocyanidin and hydroxycinnamic acid constituents (and their glycosides) of onion, tomato, egg plant and apple has been undertaken and the antioxidant activities of the phenolic extracts determined. The major phenolic antioxidant components of egg plant are chlorogenic acid in the flesh and a delphinidin conjugate in the skin. In the case of apple, the major phenolic antioxidants detected are chlorogenic acid, procyanidins/catechin compounds, rutin and phloridzin. Quercetin glycosides are well-known to be the major phenolic components of onion. Assessment of the antioxidant activities of a serving of 100 g fresh weight fruit, vegetable and comparison with previously reported findings for 150 ml beverage (500 ml portion in the case of beer), expressed in μmol Trolox equivalents show that the antioxidant activities of 1 glass (150 ml) red wine ≡ 12 glasses white wine ≡ 2 cups of tea ≡ 4 apples ≡ 5 portions of onion ≡ 5.5 portions egg plant ≡ 3.5 glasses of blackcurrant juice ≡ 3.5 (500 ml) glasses of beer ≡ 7 glasses of orange juice ≡ 20 glasses of apple juice (long life).     

Who should have their cholesterol concentration measured? What experts in the United Kingdom suggest.

General practitioners are being encouraged to participate in preventive care, including preventing coronary heart disease. Now that they can measure cholesterol concentrations in their surgeries they need to decide which patients should be screened. Several reports on measuring cholesterol concentrations in the United Kingdom were reviewed to see if experts agreed about who ought to be screened. The results showed that currently no national consensus exists, making it difficult for general practitioners to plan policies for their patients.     

Does interspecific hybridization influence evolutionary rates? An experimental study of laboratory adaptation in hybrids between Drosophila serrata and Drosophila birchii.

The low initial fitness of progeny from interspecific crosses in animals and the rarity of interspecific hybridization in natural environments have led to a debate about the evolutionary importance of this phenomenon. Here we directly assess the effects of hybridization between Drosophila serrata and Drosophila birchii on evolutionary rates. We looked at the effects on laboratory adaptation over 30 generations in two laboratory environments, one of which involved nutrition and temperature stress. Laboratory adaptation occurred over time in both environments as reflected by a marked change in viability. However, whilst hybrid lines at no stage performed poorly relative to parental lines, their rate of adaptation never exceeded that of the parentals. Thus, there was no evidence that hybridization increased evolutionary rates. Instead, hybrid lines converged phenotypically with one of the parental species.     

What really matters in end-of-life discussions? Perspectives of patients in hospital with serious illness and their families

Background:

The guideline-recommended elements to include in discussions about goals of care with patients with serious illness are mostly based on expert opinion. We sought to identify which elements are most important to patients and their families.

Methods:

We used a cross-sectional study design involving patients from 9 Canadian hospitals. We asked older adult patients with serious illness and their family members about the occurrence and importance of 11 guideline-recommended elements of goals-of-care discussions. In addition, we assessed concordance between prescribed goals of care and patient preferences, and we measured patient satisfaction with goals-of-care discussions using the Canadian Health Care Evaluation Project (CANHELP) questionnaire.

Results:

Our study participants included 233 patients (mean age 81.2 yr) and 205 family members (mean age 60.2 yr). Participants reported that clinical teams had addressed individual elements of goals-of-care discussions infrequently (range 1.4%–31.7%). Patients and family members identified the same 5 elements as being the most important to address: preferences for care in the event of life-threatening illness, values, prognosis, fears or concerns, and questions about goals of care. Addressing more elements was associated with both greater concordance between patients’ preferences and prescribed goals of care, and greater patient satisfaction.

Interpretation:

We identified elements of goals-of-care discussions that are most important to older adult patients in hospital with serious illness and their family members. We found that guideline-recommended elements of goals-of-care discussions are not often addressed by health care providers. Our results can inform interventions to improve the determination of goals of care in the hospital setting.In Canada, dying is often an in-hospital, technology-laden experience.^1–4 Rates of cardiopulmonary resuscitation (CPR) before death continue to increase among older adult patients in hospital,⁵ and one-fifth of deaths in hospital occur in an intensive care unit.^1,2,6,7 These observations contrast sharply with patient-reported preferences. A recent Canadian study found that 80% of older adult patients in hospital with a serious illness prefer a less aggressive and more comfort-oriented end-of-life care plan that does not include CPR.⁸Such patients and their families have identified communication with health care providers and decision-making about goals of care as high priorites for improving end-of-life care in Canada.^9,10 We define “decision-making about goals of care” as an end-of-life communication and decision-making process that occurs between a clinician and a patient (or a substitute decision-maker if the patient is incapable) in an institutional setting to establish a plan of care. Often, this process includes deciding whether to use life-sustaining treatments.¹¹ Current guidelines recommend that health care providers address 11 key elements when discussing goals of care with patients and families (Box 1).^12–14 However, these elements are mostly based on expert opinion and lack input from patients and their families.

Box 1:

Key elements of goals-of-care discussions with patients in hospital with serious illness^12–14

• Ask about previous discussions or written documentation about the use of life-sustaining treatments
• Offer a time to meet to discuss goals of care
• Provide information about advance care planning to review before conversations with the physician
• Disclose prognosis
• Ask about patients’ values (i.e., what is important to them when considering health care decisions)
• Provide information about outcomes, benefits and risks of life-sustaining treatments
• Provide information about outcomes, benefits and risks of comfort measures
• Prompt for additional questions about goals of care
• Provide an opportunity to express fears or concerns
• Ask about preferences for care in the event of a life-threatening illness
• Facilitate access to legal documents to record patients’ wishes

Our primary objective was to determine which of these elements are most important to patients and their families. In addition, we examined whether these discussions were associated with concordance between patients’ (or family members’) preferences and prescribed goals of care, and with satisfaction with end-of-life communication and decision-making.     

Ecological and Genetic Interactions in Drosophila–parasitoids Communities: A Case Study with D. Melanogaster, D. Simulans and their Common Leptopilina Parasitoids in Southe-astern France

Drosophila species are attacked by a number of parasitoid wasps, which constitute an important factor of population regulation. Since Drosophila melanogaster and Drosophila simulans share common parasitoid species, their ecology and evolution can hardly be understood without considering parasitoids. After a short review of data available on Drosophila-parasitoid interactions involving D. melanogaster and D. simulans as hosts, we report field and laboratory experiments investigating the ecological role of Leptopilina parasitoids in Drosophila communities of southern France. Seasonal survey of species abundance shows that strong interspecific interactions occur at both tropic levels. D. simulans progressively replaces D. melanogaster in southern areas suggesting competitive displacement. Parasitoids are responsible for very high Drosophila mortality (up to 90% in some fruits). Field data emphasize the importance of selective pressure that parasitoids exert on Drosophila communities. The two Leptopilina parasites (L. heterotoma and L boulardi) have different local abundances, which vary in time, and they also compete for hosts. We show that parasitoids can mediate the coexistence of D. melanogaster and D. simulans in the laboratory, and thus may contribute to their puzzling coexistence in the field. Conversely, hosts exert selective pressures on parasitoids, and development on either D. melanogaster or D. simulans strongly affects fitness of adult wasps in a temperature-dependent fashion. Local variation in host species abundance and diversity could thus account for the genetic differentiation we observed in one parasitoid species. Despite laboratory studies cannot fully explain complex field situations, it is clear that the ecology and evolution of Drosophila populations and communities, especially D. melanogaster and D. simulans, are strongly constrained by parasitoids, which should receive more attention.     

The role of gut hormones in controlling the food intake. What is their role in emerging diseases?

Central nervous system (CNS) receives peripheral relevant information that are able to regulate individual's energy balance through metabolic, neural, and endocrine signals. Ingested nutrients come into contact with multiple sites in the gastrointestinal tract that have the potential to alter peptide and neural signaling. There is a strong relationship between CNS and those peripheral signals (as gastrointestinal hormones) in the control of food intake. The purpose of this review is to give updated information about the role of gut hormones as mediators of feeding behavior and of different nutrients in modulating gut hormones production. The role of gut hormones in the pathogenesis of emerging diseases as obesity and non-alcoholic fatty liver disease (NAFLD) is also discussed together with the possible role of these peripheral signals as targets of future therapeutic options.     

What does the fruitless gene tell us about nature vs. nurture in the sex life of Drosophila?

The fruitless (fru) gene in Drosophila has been proposed to play a master regulator role in the formation of neural circuitries for male courtship behavior, which is typically considered to be an innate behavior composed of a fixed action pattern as generated by the central pattern generator. However, recent studies have shed light on experience-dependent changes and sensory-input-guided plasticity in courtship behavior. For example, enhanced male-male courtship, a fru mutant “hallmark,” disappears when fru-mutant males are raised in isolation. The fact that neural fru expression is induced by neural activities in the adult invites the supposition that Fru as a chromatin regulator mediates experience-dependent epigenetic modification, which underlies the neural and behavioral plasticity.     

What is winter? Modeling spatial variation in bat host traits and hibernation and their implications for overwintering energetics

White‐nose syndrome (WNS) has decimated hibernating bat populations across eastern and central North America for over a decade. Disease severity is driven by the interaction between bat characteristics, the cold‐loving fungal agent, and the hibernation environment. While we further improve hibernation energetics models, we have yet to examine how spatial heterogeneity in host traits is linked to survival in this disease system. Here, we develop predictive spatial models of body mass for the little brown myotis (Myotis lucifugus) and reassess previous definitions of the duration of hibernation of this species. Using data from published literature, public databases, local experts, and our own fieldwork, we fit a series of generalized linear models with hypothesized abiotic drivers to create distribution‐wide predictions of prehibernation body fat and hibernation duration. Our results provide improved estimations of hibernation duration and identify a scaling relationship between body mass and body fat; this relationship allows for the first continuous estimates of prehibernation body mass and fat across the species'' distribution. We used these results to inform a hibernation energetic model to create spatially varying fat use estimates for M. lucifugus. These results predict WNS mortality of M. lucifugus populations in western North America may be comparable to the substantial die‐off observed in eastern and central populations.