Seasonal priority effects: Implications for invasion and restoration in California coastal sage scrub

Competition from exotic annual grasses (EAGs) threatens native plant communities in California. Coastal sage scrub communities have substantially diminished in area over the last century, in some instances by greater than 90%, while EAGs continue to proliferate. Several mechanisms may explain the success of EAGs, including the suppression of native seedlings by accumulated litter, exhaustion of soil moisture, and low seed production or dispersal of natives. 
The timing and magnitude of rainfall plays a significant role in determining the survival and reproduction of plant species in Mediterranean ecosystems. Populations of annuals fluctuate greatly from year to year, corresponding with variability in autumn precipitation. EAGs in California germinate quickly following small threshold rain events, whereas native species have more complex germination cues, such that exotic annual grasses become active earlier in the growing season. In this way, EAGs may exhibit a priority effect over native plant species with respect to establishment; however, they may have reduced success if their germination is induced at a time followed by a substantial drought (for instance, in the summer) so that they will not persist. 
The goal of this investigation is 1) to evaluate whether seasonal priority effects contribute to community-level patterns of abundance, and 2) whether late summer watering could be a feasible restoration technique for suppression of exotic annual grasses and weeds in Mediterranean ecosystems

Gender and Family Formation in Uttar Pradesh, India

While modernising influences affect many facets of the lives of millions of Indian families, there remain deep-rooted socio-cultural practices and traditions that survive and become engendered in new institutional mechanisms. Labour market policy is but one example where age-old ethnic affiliations distort governmental efforts and find new ways of expressing themselves. Efforts over the past decade to slow the rate of population growth, by encouraging adoption of modern family planning methods have failed to tackle son preference and have caused the sex ratios at birth to be worse than at any other time in the nation's history. This is particularly so in urban India, even among the more educated populace, and it is worsening. This thesis sets out to assess the way in which such gender considerations affect family formation decisions, primarily concerning the quantity and quality of children, with an appreciation of the dynamic nature of the problem. First we assess how fertility preferences and past child outcomes affect the demand for family planning and how behaviours associated with the greater autonomy of women impact upon this process. The empirical work makes use of data from the latest round of the National Family Health Survey (NFHS) for India, 1999, for the state of Uttar Pradesh, in a simultaneous equation framework, in an effort to take account of the joint determination of many of the variables inherent in modelling such dynamic processes with cross-sectional data. We find that although women's autonomy has been held up as a means of achieving lower fertility, the two do not necessarily go hand in hand, unless coupled with the wider participation of women. Unless the primary social and economic motivations for preferring sons are tackled and dismantled through legislation and through changes to social attitudes, superficial policies to promote the well-being of women will have little real impact and may lead to worsening female child outcomes. One of the policies heralded to achieve the deeper goal of gender equality has been the promotion of education of female children, who as a group lag well behind their male counterparts on both literacy and numeracy rates. We thus turn our attention to investigating the way in which household time allocation decisions are made, focusing on the parental choice of each child's main activity; to go to school, to work in the home, or in the formal labour market, in an effort to understand how the household's opportunities and resource constraints, along with social norms impact such decisions. While some state governments are offering cash incentives to families to keep their female children in school and unmarried, significant labour market discrimination against women continues and constrains the value of this government investment. Making use of the same NFHS data for Uttar Pradesh, we estimate each child's trinomial time allocation with competing speci cations and then compare the results. The standard multinomial logit model is estimated initially but imposes some fairly tight assumptions on behaviour and the resultant data, that are unlikely to hold in the present application. A Mixed Logit model is then estimated that is able to bring greater flexibility and descriptive richness than is possible with the standard Logit model. Estimation results are compared and con firm the ability of the Mixed Logit to capture more fully the unobserved heterogeneity inherent in the data and to allow for correlation in the errors across children of the same family that is not permitted within the standard logit setup

The History, Development and Impact of Computed Imaging in Neurological Diagnosis and Neurosurgery: CT, MRI, and DTI

A steady series of advances in physics, mathematics, computers and clinical imaging science have progressively transformed diagnosis and treatment of neurological and neurosurgical disorders in the 115 years between the discovery of the X-ray and the advent of high resolution diffusion based functional MRI. The story of the progress in human terms, with its battles for priorities, forgotten advances, competing claims, public battles for Nobel Prizes, and patent priority litigations bring alive the human drama of this remarkable collective achievement in computed medical imaging

Nebulised hypertonic saline solution for acute bronchiolitis in infants (Review)

Acute viral bronchiolitis is the most common lower respiratory tract infection in infants up to two years old. Currently there is no effective treatment so standard treatment remains supportive care. Airway oedema (abnormal accumulation of fluid) and mucus plugging can cause wheezing and difficulty breathing in these patients. Nebulised hypertonic saline may be a beneficial treatment to manage acute bronchiolitis because it can improve airway hygiene. This review was conducted to assess the effects of hypertonic (≥ 3%) saline solution administered via a nebuliser in infants with acute bronchiolitis, compared with nebulised normal (0.9%) saline. The establishment of a therapeutic role for hypertonic saline solution may provide a cheap and effective therapy for these patients. We included 11 randomised trials involving 1090 infants with mild to moderate bronchiolitis. All but one of the 11 trials are considered as high-quality studies with low risk of error (i.e. bias) in their conclusions. Meta-analysis suggests that nebulised hypertonic saline could lead to a reduction of 1.2 days in the mean length of hospital stay among infants hospitalised for non-severe acute bronchiolitis and improve the clinical severity score in both outpatient and inpatient populations. No significant short-term effects (at 30 to 120 minutes) of one to three doses of nebulised hypertonic saline were observed among emergency department patients. However, more trials are needed to address this question. There were no significant adverse effects noted with the use of nebulised hypertonic saline when administered along with bronchodilators. Given the clinically relevant benefit and good safety profile, nebulised hypertonic saline used in conjunction with bronchodilators should be considered an effective and safe treatment for infants with mild to moderate acute viral bronchiolitis

Pharmacological profiling of the hemodynamic effects of cannabinoid ligands: a combined in vitro and in vivo approach.

The receptors mediating the hemodynamic responses to cannabinoids are not clearly defined due to the multifarious pharmacology of many commonly used cannabinoid ligands. While both CB1 and TRPV1 receptors are implicated, G protein-coupled receptor 55 (GPR55) may also mediate some of the hemodynamic effects of several atypical cannabinoid ligands. The present studies attempted to unravel the pharmacology underlying the in vivo hemodynamic responses to ACEA (CB1 agonist), O-1602 (GPR55 agonist), AM251 (CB1 antagonist), and cannabidiol (CBD; GPR55 antagonist). Agonist and antagonist profiles of each ligand were determined by ligand-induced GTPcS binding in membrane preparations expressing rat and mouse CB1 and GPR55 receptors. Blood pressure responses to ACEA and O-1602 were recorded in anesthetized and conscious mice (wild type, CB1 / and GPR55 / ) and rats in the absence and presence of AM251 and CBD. ACEA demonstrated GTPcS activation at both receptors, while O-1602 only activated GPR55. AM251 exhibited antagonist activity at CB1 and agonist activity at GPR55, while CBD demonstrated selective antagonist activity at GPR55. The depressor response to ACEA was blocked by AM251 and attenuated by CBD, while O-1602 did not induce a depressor response. AM251 caused a depressor response that was absent in GPR55 / mice but enhanced by CBD, while CBD caused a small vasodepressor response that persisted in GPR55 / mice. Our findings show that assessment of the pharmacological profile of receptor activation by cannabinoid ligands in in vitro studies alongside in vivo functional studies is essential to understand the role of cannabinoids in hemodynamic control

Distinct responses of niche and fitness differences to water availability underlie variable coexistence outcomes in semi-arid annual plant communities

Climate change is predicted to have profound consequences for multispecies coexistence, and thus, patterns of biological diversity. These consequences will be mediated by direct and indirect impacts of environmental change on species’ vital rates and interactions. While the impacts of environmental change on individual species has received much attention to date, the consequences for coexistence mediated by changes in the strength and direction of multispecies interactions are not as well understood. To investigate how coexistence dynamics may be sensitive to environmental change, we conducted a field experiment in a diverse semi-arid annual plant system. We imposed a water manipulation treatment in two sites that vary in aridity and associated rainfall. Focusing on four common annual plant species in these sites, we quantified the fecundity (seed production) of individuals in response to a gradient of intra- and interspecific competitor densities and aridity. We then used these fecundities to parameterize an annual plant population model and examine the influence of aridity and species identity on resultant coexistence dynamics (as a function of stabilizing niche differences and fitness inequalities). While the responses of some vital rates and competitive impacts to watering varied somewhat predictably across sites, coexistence metrics encapsulating changes in these vital rates and interaction strengths did not. Fitness inequalities among our focal species were driven largely by differences in sensitivity to competition, which were almost always much greater than the magnitude of stabilizing niche differences. These findings were surprising given observational evidence suggesting that these species do coexist at local scales in these natural communities. Synthesis. Our study is one of the first to explicitly consider the influence of environmental variation on the individual components of coexistence outcomes. We show that environmental change has the ability to influence coexistence not only through direct pathways (i.e., vital rates), but also indirect pathways (i.e., species interactions). Despite the consistency of many of the responses of these individual components to environmental variation, their combined influence on predictions of both current and future coexistence remains unclear