Excited states of spherium

We report analytic solutions of a recently discovered quasi-exactly solvable model consisting of two electrons, interacting {\em via} a Coulomb potential, but restricted to remain on the surface of a $\mathcal{D}$-dimensional sphere. Polynomial solutions are found for the ground state, and for some higher ($L\le3$) states. Kato cusp conditions and interdimensional degeneracies are discussed.Comment: 6 pages, 2 figures, to appear in Mol. Phy

The process of establishing implementing and maintaining a social support infant feeding programme

Objective To describe the process of establishing and implementing a social support infant feeding intervention. Design This paper outlines the initial stages of a randomised controlled trial which assessed the effectiveness of a social support intervention on a range of infant feeding outcomes. Details are presented of the processes involved in recruiting, training and supporting a group of volunteers who provided support to the study sample. Setting Camden and Islington, London, UK. Results Initial networking with local agencies and organisations provided invaluable information and contacts. Employing a dedicated volunteer co-ordinator is vitally important in the recruitment, training and support of volunteers. Providing child care and travel expenses is an essential incentive for volunteers with young children. Advertisements placed in local newspapers were the most successful means of recruiting volunteers. Appropriate training is needed to equip volunteers with the necessary knowledge and skills to provide effective support. Particular emphasis in the training focused upon developing the necessary interpersonal skills and self-confidence. The evaluation of the training programme demonstrated that it improved volunteers’ knowledge and reported confidence. The provision of ongoing support is also essential to maintain volunteers’ interest and enthusiasm. The retention of volunteers is, however, a key challenge. Conclusions The processes outlined in this paper have demonstrated the feasibility of successfully establishing, implementing and maintaining a community-based social support infant feeding programme. The experiences described provide useful insights into the practical issues that need to be addressed in setting up a social support intervention

A mutant of Burkholderia pseudomallei, auxotrophic in the branched chain amino acid biosynthetic pathway, is attenuated and protective in a murine model of melioidosis.

Using a transposon mutagenesis approach, we have identified a mutant of Burkholderia pseudomallei that is auxotrophic for branched chain amino acids. The transposon was shown to have interrupted the ilvI gene encoding the large subunit of the acetolactate synthase enzyme. Compared to the wild type, this mutant was significantly attenuated in a murine model of disease. Mice inoculated intraperitoneally with the auxotrophic mutant, 35 days prior to challenge, were protected against a challenge dose of 6,000 median lethal doses of wild-type B. pseudomallei

Hydrological and climatological change associated with glacial recession in the Rwenzori Mountains of Uganda

The areal extent of tropical icefields in the Rwenzori Mountains of East Africa has reduced steadily over the last century from 7.5 km^{2} 2 in 1906 to <1 km^{2} in 2003. Considerable debate persists regarding the impact of deglaciation on alpine riverflow and changes in climate driving glacial recession in the East African Highlands. Recent field surveys combined with historical observations reveal continued, rapid retreat in the terminal positions of valley glaciers (Speke, Elena). Observed acceleration in the rate of termini retreat since the 1960s is shown to arise, in part, from the morphologies of the glaciers and the beds within which those glaciers reside. Historical data combined with the first measurements of alpine riverflow in the Rwenzori Mountains show that the contribution of meltwater flows from dwindling icefields to alpine riverflow is negligible, contributing <0.5% of the mean annual river discharge recorded at the base of the mountains. Preliminary high-frequency monitoring of air temperature and humidity in the vicinity of icefields on the Rwenzori Mountains indicates that elevated daily maximum air temperatures coincide with episodic reductions in relative humidity and increased meltwater fluxes observed during the dry season. A sustained reduction in humidity to account for observed deglaciation is not evident from records of lowland precipitation, humidity or river discharge. Lakelevel records in East Africa are also inconsistent with a sudden decrease in regional humidity around 1880AD that is proposed to have triggered deglaciation in the East African Highlands. Water levels in the lakes proximate to the icefields of Mount Kenya and Kilimanjaro are rising in the late 19th century when glaciers on these mountains are observed to be in retreat. Lake levels do not, furthermore, indicate that enhanced humidity over the 19th century prior to 1880AD relative to the 20th century. Evidence of warming over the latter half of the 20th century and an earlier onset of deglaciation (~1870AD) from meteorological and palaeolimnological data suggest that the timing and drivers of deglaciation in the Rwenzori Mountains are consistent with the recession of alpine icefields elsewhere in the tropics

The Actinomyosin Motor Drives Malaria Parasite Red Blood Cell Invasion but Not Egress.

Apicomplexa are obligate intracellular parasites that actively invade, replicate within, and egress from host cells. The parasite actinomyosin-based molecular motor complex (often referred to as the glideosome) is considered an important mediator of parasite motility and virulence. Mature intracellular parasites often become motile just prior to egress from their host cells, and in some genera, this motility is important for successful egress as well as for subsequent invasion of new host cells. To determine whether actinomyosin-based motility is important in the red blood cell egress and invasion activities of the malaria parasite, we have used a conditional genetic approach to delete GAP45, a primary component of the glideosome, in asexual blood stages of Plasmodium falciparum Our results confirm the essential nature of GAP45 for invasion but show that P. falciparum does not require a functional motor complex to undergo egress from the red blood cell. Malarial egress therefore differs fundamentally from induced egress in the related apicomplexan Toxoplasma gondiiIMPORTANCE Clinical malaria results from cycles of replication of single-celled parasites of the genus Plasmodium in red blood cells. Intracellular parasite replication is followed by a highly regulated, protease-dependent process called egress, in which rupture of the bounding membranes allows explosive release of daughter merozoites which rapidly invade fresh red cells. A parasite actinomyosin-based molecular motor (the glideosome) has been proposed to provide the mechanical force to drive invasion. Studies of the related parasite Toxoplasma gondii have shown that induced egress requires parasite motility, mediated by a functional glideosome. However, whether the glideosome has a similar essential role in egress of malaria merozoites from red blood cells is unknown. Here, we show that although a functional glideosome is required for red blood cell invasion by Plasmodium falciparum merozoites, it is not required for egress. These findings place further emphasis on the key role of the protease cascade in malarial egress

Egg size investment in superb fairy-wrens: helper effects are modulated by climate

Natural populations might exhibit resilience to changing climatic conditions if they already show adaptive flexibility in their reproductive strategies. In cooperative breeders, theory predicts that mothers with helpers should provide less care when environmental conditions are favourable, but maintain high investment when conditions are challenging. Here, we test for evidence of climate-mediated flexibility in maternal investment in the cooperatively breeding superb fairy-wren Malurus cyaneus We focus on egg size because in this species egg size influences offspring size, and females reduce egg investment when there are helpers at the nest. We report that females lay larger eggs during dry, hot conditions. However, the effect of temperature is modulated by the presence of helpers: the average egg size of females with helpers is reduced during cooler conditions but increased during hot conditions relative to females without helpers. This appears to reflect plasticity in egg investment rather than among female differences. Analysis of maternal survival suggests that helped females are better able to withstand the costs of breeding in hot conditions than females without helpers. Our study suggests that females can use multiple, independent cues to modulate egg investment flexibly in a variable environment.The work was funded by grants from the Australian Research Council and National Geographic (NEL), and the Royal Society (AFR and RMK)

ERCC1 expression and RAD51B activity correlate with cell cycle response to platinum drug treatment not DNA repair

Background: The H69CIS200 and H69OX400 cell lines are novel models of low-level platinum-drug resistance. Resistance was not associated with increased cellular glutathione or decreased accumulation of platinum, rather the resistant cell lines have a cell cycle alteration allowing them to rapidly proliferate post drug treatment. Results: A decrease in ERCC1 protein expression and an increase in RAD51B foci activity was observed in association with the platinum induced cell cycle arrest but these changes did not correlate with resistance or altered DNA repair capacity. The H69 cells and resistant cell lines have a p53 mutation and consequently decrease expression of p21 in response to platinum drug treatment, promoting progression of the cell cycle instead of increasing p21 to maintain the arrest. Conclusion: Decreased ERCC1 protein and increased RAD51B foci may in part be mediating the maintenance of the cell cycle arrest in the sensitive cells. Resistance in the H69CIS200 and H69OX400 cells may therefore involve the regulation of ERCC1 and RAD51B independent of their roles in DNA repair. The novel mechanism of platinum resistance in the H69CIS200 and H69OX400 cells demonstrates the multifactorial nature of platinum resistance which can occur independently of alterations in DNA repair capacity and changes in ERCC1

Agency, qualia and life: connecting mind and body biologically

Many believe that a suitably programmed computer could act for its own goals and experience feelings. I challenge this view and argue that agency, mental causation and qualia are all founded in the unique, homeostatic nature of living matter. The theory was formulated for coherence with the concept of an agent, neuroscientific data and laws of physics. By this method, I infer that a successful action is homeostatic for its agent and can be caused by a feeling - which does not motivate as a force, but as a control signal. From brain research and the locality principle of physics, I surmise that qualia are a fundamental, biological form of energy generated in specialized neurons. Subjectivity is explained as thermodynamically necessary on the supposition that, by converting action potentials to feelings, the neural cells avert damage from the electrochemical pulses. In exchange for this entropic benefit, phenomenal energy is spent as and where it is produced - which precludes the objective observation of qualia

Happiness and education: troubling students for their own contentment

Currently higher education strategies seem to concentrate on the expedient, developing skills that can secure employment in the world of work. Following Dreyfus and Spinosa (2003), this may have immediate advantages, but in totalising pedagogic practices it may restrict our openness to people and to our own contentment with ourselves. Valuable as this may be as a way to satisfy politico-economic policy imperatives, it strays from education as an edifying process where personal development represents, through the facing up to distress and despair, an unsettling of our developing identity and a negation of our immediate desire satisfaction. Such an unsettling is not intended to give pleasure or satisfaction in the normative way in which the imperative of happiness has been used in student satisfaction surveys or in the wider societal context that this totalisation represents (Ahmed 2010). What I propose for higher education is not a dominant priority to feed the happiness for others but a mission to personal contentment revealed through realising student potentialities to them and so recognising their limitations as part of seeking an attunement to contentment