3,310 research outputs found
Abstain or die: The development of HIV/AIDS policy in Botswana
This paper traces the development of policies dealing with
HIV/AIDS in Botswana from their beginning in the late 1980s to the current
programme to provide population-wide anti-retroviral therapy (ARV). Using
a variety of source material, including long-term ethnographic research, it
seeks to account for the failure of Western-inspired approaches in dealing
with the pandemic. It does this by looking at the cultural and institutional
features that have created resistance to the message and inhibited effective
implementation. The negative response to the first educational campaign
stressing condom use is described and contextualized in terms of Tswana
ideas of morality and illness. Nor, as was initially expected, did the
introduction of free ARV therapy operate to break the silence and stigma
that had developed around the disease. Take-up was very slow, and did not
operate to encourage widespread testing. In 2003, key policymakers in
Botswana began to argue for a break with the AIDS ‘exceptionalism’
position, with its emphasis on voluntarism, confidentiality and the human
rights of patients. This resulted in routine testing being introduced in 2004.
This links to a major argument running through the paper which is that the
failure of policy cannot be attributed solely to the nature of local populations.
Western cultural assumptions about ‘good practice’ also require critical
examination
Histone H1 is essential for mitotic chromosome architecture and segregation in Xenopus laevis egg extracts.
During cell division, condensation and resolution of chromosome arms and the assembly of a functional kinetochore at the centromere of each sister chromatid are essential steps for accurate segregation of the genome by the mitotic spindle, yet the contribution of individual chromatin proteins to these processes is poorly understood. We have investigated the role of embryonic linker histone H1 during mitosis in Xenopus laevis egg extracts. Immunodepletion of histone H1 caused the assembly of aberrant elongated chromosomes that extended off the metaphase plate and outside the perimeter of the spindle. Although functional kinetochores assembled, aligned, and exhibited poleward movement, long and tangled chromosome arms could not be segregated in anaphase. Histone H1 depletion did not significantly affect the recruitment of known structural or functional chromosomal components such as condensins or chromokinesins, suggesting that the loss of H1 affects chromosome architecture directly. Thus, our results indicate that linker histone H1 plays an important role in the structure and function of vertebrate chromosomes in mitosis
Seeking large-scale magnetic fields in a pure-disk dwarf galaxy NGC 2976
It is still unknown how magnetic field-generation mechanisms could operate in
low-mass dwarf galaxies. Here, we present a detailed study of a nearby
pure-disk dwarf galaxy NGC 2976. Unlike previously observed dwarf objects, this
galaxy possesses a clearly defined disk. For the purpose of our studies, we
performed deep multi-frequency polarimetric observations of NGC 2976 with the
VLA and Effelsberg radio telescopes. Additionally, we supplement them with
re-imaged data from the WSRT-SINGS survey. The magnetic field morphology
discovered in NGC 2976 consists of a southern polarized ridge. This structure
does not seem to be due to just a pure large-scale dynamo process (possibly
cosmic-ray driven) at work in this object, as indicated by the RM data and
dynamo number calculations. Instead, the field of NGC 2976 is modified by past
gravitational interactions and possibly also by ram pressure inside the M 81
galaxy group environment. The estimates of total (7 muG) and ordered (3 muG)
magnetic field strengths, as well as degree of field order (0.46), which is
similar to those observed in spirals, suggest that tidally generated magnetized
gas flows can further enhance dynamo action in the object. NGC 2976 is
apparently a good candidate for the efficient magnetization of its
neighbourhood. It is able to provide an ordered (perhaps also regular) magnetic
field into the intergalactic space up to a distance of about 5 kpc. Tidal
interactions (and possibly also ram pressure) can lead to the formation of
unusual magnetic field morphologies (like polarized ridges) in galaxies out of
the star-forming disks, which do not follow any observed component of the
interstellar medium (ISM), as observed in NGC 2976. These galaxies are able to
provide ordered magnetic fields far out of their main disks.Comment: 16 page
Simple analysis of off-axis solenoid fields using the scalar magnetostatic potential: application to a Zeeman-slower for cold atoms
In a region free of currents, magnetostatics can be described by the Laplace
equation of a scalar magnetic potential, and one can apply the same methods
commonly used in electrostatics. Here we show how to calculate the general
vector field inside a real (finite) solenoid, using only the magnitude of the
field along the symmetry axis. Our method does not require integration or
knowledge of the current distribution, and is presented through practical
examples, including a non-uniform finite solenoid used to produce cold atomic
beams via laser cooling. These examples allow educators to discuss the
non-trivial calculation of fields off-axis using concepts familiar to most
students, while offering the opportunity to introduce important advancements of
current modern research.Comment: 6 pages. Accepted in the American Journal of Physic
On the use of low-cost computer peripherals for the assessment of motor dysfunction in Parkinson’s disease – Quantification of bradykinesia using target tracking tasks
The potential of computer games peripherals to measure the motor dysfunction in Parkinson’s diseases is assessed. Of particular interest is the quantification of bradykinesia. Previous studies used modified or custom haptic interfaces, here an unmodified force feedback joystick and steering wheel are used with a laptop. During testing an on screen cursor moves in response to movements of the peripheral, the user has to track a continuously moving target (pursuit tracking), or move to a predetermined target (step tracking). All tasks use movement in the horizontal axis, allowing use of joystick or steering wheel. Two pursuit tracking tasks are evaluated, pseudo random movement, and a swept frequency task. Two step tracking tasks are evaluated, movement between two or between two of five fixed targets. Thirteen patients and five controls took part on a weekly basis. Patients were assessed for bradykinesia at each session using standard clinical measures. A range of quantitative measures was developed to allow comparison between and within patients and controls using ANOVA. Both peripherals are capable of discriminating between controls and patients, and between patients with different levels of bradykinesia. Recommendations for test procedures and peripherals are given
Lifestyle intervention in individuals with impaired glucose regulation affects Caveolin-1 expression and DNA methylation
© 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Aims: We investigated whether a lifestyle intervention could influence expression and DNA methylation of diabetes-related genes in patients with impaired glucose regulation (IGR), the results were compared to bariatric surgery, considering it an intensive change. Methods: Twenty participants with IGR had adipose tissue biopsy and blood collected pre- and post-lifestyle (6 months) intervention; 12 obese patients had subcutaneous fat taken before and after bariatric surgery. RNA/DNA was extracted from all samples and underwent qPCR. DNA was bisulphite converted and 12 CpG sites of Caveolin-1 (CAV1) promoter were pyrosequenced. Results: lifestyle intervention resulted in opposite direction changes in fat tissue and blood for CAV1 expression and DNA methylation and these changes were correlated between tissues, while no significative differences were found in CAV1 expression after bariatric surgery. Conclusions: Our findings suggest a role for CAV1 in modulating adipocyte function as a consequence of lifestyle changes, as exercises and diet. These results may provide insights into new therapeutic targets for diabetes prevention
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