X-ray spectral transitions of black holes from RXTE All-Sky Monitor

We have analysed X-ray outbursts from several Galactic black hole (GBH) transients, as seen by the ASM on board RXTE. We have used the best estimates of distance and black hole mass to find their luminosity (scaled to the Eddington limit), which allowed for direct comparison of many sources. We have found two distinct hard-to-soft state transitions in the initial part of the outburst. The distinction is made on the basis of the transition luminosity, its duration, the shape of the track in the hardness-luminosity diagram, and evolution of the hardness ratio. The bright/slow transition occurs at ~30 per cent of Eddington (estimated bolometric) luminosity and takes >~30 days, during which the source quickly reaches the intermediate/very high state and then proceeds to the soft state at much slower pace. The dark/slow transition is less luminous (<~10 per cent of Eddington), shorter (<~15 days) and the source does not slow its transition rate before reaching the soft state. We speculate that the distinction is due to irradiation and evaporation of the disc, which sustains the Comptonizing corona in the bright intemediate/very high state.Comment: Revised version, accepted for publication in MNRA

The role of ICNA in Africa

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106854/1/j.1469-8749.2011.03972.x.pd

Clinical characteristics of children with epilepsy managed at an urban hospital in Africa: a retrospective study

Background: Most children with epilepsy reside in resource-limited regions such as sub-Saharan Africa, where the majority of studies have been conducted in rural areas with limited investigations. Medical records from children with epilepsy seen at an urban hospital in Kenya were examined to provide a comprehensive description of epilepsy in children from this hospital. Methods: A retrospective observational study was conducted which involved reviewing medical records of 426 epilepsy patients (260 males and 166 females) aged 0 - 18 years, seen in Nairobi, Kenya between February 2011 and December 2014. Results: The most frequent age at presentation; documented in 29% was in infancy. Generalized seizures due to structural brain abnormalities were the most common form of epilepsy (28%). Lennox-Gastaut Syndrome was the most common electroclinical syndrome (7%). Focal seizures and focal seizures with loss of awareness were identified in 12% of the population. There were no cases of childhood absence epilepsy in this group. Brain atrophy was the most common MRI finding, occurring in a fifth of the population (20%), while cystic encephalomalacia occurred in 13%. Half (50%) of all EEG recordings performed for this cohort were abnormal. Generalized seizures due to structural brain abnormalities and Lennox-Gastaut Syndrome (LGS) were significant predictors of a treatment history of three or more AEDs. At the conclusion of the review period, 16% of the patients had not visited the clinic for more than 12 months and were considered to be lost to follow-up. Conclusion: The highest frequency of epilepsy cases was documented in children less than one year of age. Generalized seizures due to structural abnormalities and Lennox-Gastaut syndrome were the most common seizure type and syndrome. Improvement of public awareness of different types of seizures in children may increase identification of children with childhood absence epilepsy

Dynamical inference from a kinematic snapshot: The force law in the Solar System

If a dynamical system is long-lived and non-resonant (that is, if there is a set of tracers that have evolved independently through many orbital times), and if the system is observed at any non-special time, it is possible to infer the dynamical properties of the system (such as the gravitational force or acceleration law) from a snapshot of the positions and velocities of the tracer population at a single moment in time. In this paper we describe a general inference technique that solves this problem while allowing (1) the unknown distribution function of the tracer population to be simultaneously inferred and marginalized over, and (2) prior information about the gravitational field and distribution function to be taken into account. As an example, we consider the simplest problem of this kind: We infer the force law in the Solar System using only an instantaneous kinematic snapshot (valid at 2009 April 1.0) for the eight major planets. We consider purely radial acceleration laws of the form a_r = -A [r/r_0]^{-\alpha}, where r is the distance from the Sun. Using a probabilistic inference technique, we infer 1.989 < \alpha < 2.052 (95 percent interval), largely independent of any assumptions about the distribution of energies and eccentricities in the system beyond the assumption that the system is phase-mixed. Generalizations of the methods used here will permit, among other things, inference of Milky Way dynamics from Gaia-like observations

Unique Changes in Mitochondrial Genomes Associated with Reversions of S-Type Cytoplasmic Male Sterility in Maizemar

Cytoplasmic male sterility (CMS) in plants is usually associated with the expression of specific chimeric regions within rearranged mitochondrial genomes. Maize CMS-S plants express high amounts of a 1.6-kb mitochondrial RNA during microspore maturation, which is associated with the observed pollen abortion. This transcript carries two chimeric open reading frames, orf355 and orf77, both unique to CMS-S. CMS-S mitochondria also contain free linear DNA plasmids bearing terminal inverted repeats (TIRs). These TIRs recombine with TIR-homologous sequences that precede orf355/orf77 within the main mitochondrial genome to produce linear ends. Transcription of the 1.6-kb RNA is initiated from a promoter within the TIRs only when they are at linear ends. Reversions of CMS-S to fertility occur in certain nuclear backgrounds and are usually associated with loss of the S plasmids and/or the sterility-associated region. We describe an unusual set of independently recovered revertants from a single maternal lineage that retain both the S plasmids and an intact orf355/orf77 region but which do not produce the 1.6-kb RNA. A 7.3-kb inversion resulting from illegitmate recombination between 14-bp microrepeats has separated the genomic TIR sequences from the CMS-associated region. Although RNAs containing orf355/orf77 can still be detected in the revertants, they are not highly expressed during pollen development and they are no longer initiated from the TIR promoter at a protein-stabilized linear end. They appear instead to be co-transcribed with cytochrome oxidase subunit 2. The 7.3-kb inversion was not detected in CMS-S or in other fertile revertants. Therefore, this inversion appears to be a de novo mutation that has continued to sort out within a single maternal lineage, giving rise to fertile progeny in successive generations

Survey of rehabilitation support for children 0-15 years in a rural part of Kenya

Abstract Purpose: Information regarding the nature, availability and distribution of rehabilitation services for children with disabilities across developing countries is scarce, and data that do exist are of variable quality. If planning and development are to progress, information about service provision is vital. The aim was to establish the scope and nature of rehabilitation support available to children with disabilities (0-15 years) and their families in rural Kenya. Method: A comprehensive sample comprising service provision in the health and special education sectors was established. Non-governmental and community-based organisations were also included. A survey of rehabilitation services was conducted through examination of service-related documentation and key informant interviews with the heads of services. Results: Rehabilitation comprised hospital-based occupational therapy, physiotherapy and orthopaedic technology; and seven special education establishments plus an education assessment resource centre. There was one non-government organisation and one community-based organisation relevant to children with disabilities. Activities focused on assessment, diagnosis and raising community awareness. Provision was challenged by inadequate staffing, resources and transport. Government funding was supplemented variously by donations and self-sufficiency initiatives. Rehabilitation approaches appeared to be informed by professional background of practitioner, rather than the needs of child. Service documentation revealed use of inconsistent recording methods. Conclusions: The data highlight the challenges of rehabilitation, demanding greater investment in personnel and their training, more material resources, improved access to the community and better recording mechanisms. Implications for Rehabilitation There needs to be greater investment in rehabilitation provision in developing countries. Consideration of community-based initiatives is required to support better access for all. In order to argue the case for improved resources, better skills and mechanisms for recording, monitoring and evaluating practice are needed

Revisiting the ‘Sterilising Cure’ Terminology: A Call for More Patient-Centered Perspectives on HIV Cure-Related Research

The literature on HIV therapeutics research is rife with terminology associating ‘sterilisation’ with HIV cure. We find connotations of the word ‘sterilising’ problematic for the HIV cure research field. In this viewpoint, we review associations of sterilising with concepts of disinfection or cleansing, as well as coerced sterilisation. We discuss emerging findings from socio-behavioural research that show aversion from people living with HIV towards the ‘sterilising cure’ nomenclature. We call for more collaborations with people with HIV as partners to help define what would be a more acceptable terminology for describing an HIV cure

How social capital influences community support for alternative water sources

Ensuring future water security requires broad community support for changes in policy, practice, and technology, such as those involved in delivering alternative water schemes. Building community support for alternative water sources may involve a suite of engagement activities, ranging from information campaigns, through to grassroots and participatory approaches. There is increasing recognition that ‘social capital’—the degree of social connectedness, trust, and shared values within a community—is important for building support for pro-environmental policies. However, little research has examined how social capital might influence support for alternative water schemes. We surveyed a representative sample of Australian adults (n\ua0=\ua05194). Support for alternative water sources was examined using a series of questions focusing on stormwater harvesting, desalination, and recycled water. Involvement in community organisations (defined as participation or membership) was used as an indicator of social capital. Using a series of mediation analyses, we identified that community involvement is associated with support for alternative water sources, and that this effect is mediated by (i) stronger water-related social norms, (ii) greater water-related knowledge, and (iii) increased recall of water-related information. Our results also suggest that these indirect effects can be conditional upon location, employment status, life satisfaction, and language spoken within the home. These findings highlight the importance of social capital in building engagement in water-related issues, and specifically, building support for alternative water sources. In addition they highlight potential pathways for the association between social capital and support for alternative water sources for different social groups and communities

Alteration of Expression of Ca2+ Signaling Proteins and Adaptation of Ca2+ Signaling in SERCA2+/- Mouse Parotid Acini

PURPOSE: The sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), encoded by ATP2A2, is an essential component for G-protein coupled receptor (GPCR)-dependent Ca2+ signaling. However, whether the changes in Ca2+ signaling and Ca2+ signaling proteins in parotid acinar cells are affected by a partial loss of SERCA2 are not known. MATERIALS AND METHODS: In SERCA2+/- mouse parotid gland acinar cells, Ca2+ signaling, expression levels of Ca2+ signaling proteins, and amylase secretion were investigated. RESULTS: SERCA2+/- mice showed decreased SERCA2 expression and an upregulation of the plasma membrane Ca2+ ATPase. A partial loss of SERCA2 changed the expression level of 1, 4, 5-tris-inositolphosphate receptors (IP3Rs), but the localization and activities of IP3Rs were not altered. In SERCA2+/- mice, muscarinic stimulation resulted in greater amylase release, and the expression of synaptotagmin was increased compared to wild type mice. CONCLUSION: These results suggest that a partial loss of SERCA2 affects the expression and activity of Ca2+ signaling proteins in the parotid gland acini, however, overall Ca2+ signaling is unchanged.ope