551 research outputs found
The Rhodesian economy under sanctions
An analysis of the effects of sanctions, or lack thereof, of internationally imposed sanctions on the minority government of Rhodesia, circa. 1960's.Economic sanctions against Rhodesia have failed. Not only have they failed to achieve their political objective of bringing about the collapse of the existing Government, but they have also failed to depress economic activity to the extent that was intended. After 12 months of voluntary sanctions followed by eight months of mandatory United Nations sanctions there are signs that the economyâfar from wilting under the pressureâis beginning to grow once again. It would appear that the worst is past
Attitudes and practises with regard to emptying of onsite systems in Maputo, Mozambique
Rapid urbanisation as well as the rising need for water from industries and agriculture is intensifying freshwater scarcity in delta cities such as Maputo, Mozambique. Environmental pollution caused through the disposal of untreated wastewater and faecal sludge is additionally increasing water competition, posing a serious hazard to public health. Safe water reuse could hereby significantly lower the pressure on freshwater resources, still cities in developing countries lack knowledge, tools and capacities to integrate reuse into the overall (waste)water and faecal sludge management. With a city-wide onsite coverage of 90% it is essential to understand prevailing attitudes and practises along the faecal sludge management chain in order to quantify the end-use potential. This issue has been addressed through a survey of around 1,200 households in Maputo conducted by a cooperation of the Technical University of Delft and the Water and Sanitation Programme of the World Bank
Longitudinal trajectories of brain age in young individuals at familial risk of mood disorder from the Scottish Bipolar Family Study
Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels
Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress
parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient
clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (df ) of the fibrin network,
the gel network formation time (TGP ) and the shear elastic modulus, respectively. The results of this first haemorheological
application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear
stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure
of forming clots to increasing levels of shear stress produces a corresponding elevation in df , consistent with the formation of
tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded.
The scaling relationship established between shear elasticity and df for fibrin clots and whole blood confirms the fibrin network
as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies
of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase df
and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be
attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear
stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for
the study of the effects of physiological and pathological levels of shear on clot properties
Being relevant: Practical guidance for early career researchers interested in solving conservation problems
AbstractIn a human-altered world where biodiversity is in decline and conservation problems abound, there is a dire need to ensure that the next generation of conservation scientists have the knowledge, skills, and training to address these problems. So called âearly career researchersâ (ECRs) in conservation science have many challenges before them and it is clear that the status quo must change to bridge the knowledgeâaction divide. Here we identify thirteen practical strategies that ECRs can employ to become more relevant. In this context, ârelevanceâ refers to the ability to contribute to solving conservation problems through engagement with practitioners, policy makers, and stakeholders. Conservation and career strategies outlined in this article include the following: thinking âbig pictureâ during conservation projects; embracing various forms of knowledge; maintaining positive relationships with locals familiar with the conservation issue; accepting failure as a viable (and potentially valuable) outcome; daring to be creative; embracing citizen science; incorporating interdisciplinarity; promoting and practicing pro-environmental behaviours; understanding financial aspects of conservation; forming collaboration from the onset of a project; accepting the limits of technology; ongoing and effective networking; and finally, maintaining a positive outlook by focusing on and sharing conservation success stories. These strategies move beyond the generic and highlight the importance of continuing to have an open mind throughout the entire conservation process, from establishing oneâs self as an asset to embracing collaboration and interdisciplinary work, and striving to push for professional and personal connections that strengthen personal career objectives
Intelligence and neuroticism in relation to depression and psychological distress: Evidence from two large population cohorts
BACKGROUND: Neuroticism is a risk factor for selected mental and physical illnesses and is inversely associated with intelligence. Intelligence appears to interact with neuroticism and mitigate its detrimental effects on physical health and mortality. However, the inter-relationships of neuroticism and intelligence for major depressive disorder (MDD) and psychological distress has not been well examined. METHODS: Associations and interactions between neuroticism and general intelligence (g) on MDD, self-reported depression, and psychological distress were examined in two population-based cohorts: Generation Scotland: Scottish Family Health Study (GS:SFHS, n=19,200) and UK Biobank (n=90,529). The Eysenck Personality Scale Short Form-Revised measured neuroticism and g was extracted from multiple cognitive ability tests in each cohort. Family structure was adjusted for in GS:SFHS. RESULTS: Neuroticism was strongly associated with increased risk for depression and higher psychological distress in both samples. Although intelligence conferred no consistent independent effects on depression, it did increase the risk for depression across samples once neuroticism was adjusted for. Results suggest that higher intelligence may ameliorate the association between neuroticism and self-reported depression although no significant interaction was found for clinical MDD. Intelligence was inversely associated with psychological distress across cohorts. A small interaction was found across samples such that lower psychological distress associates with higher intelligence and lower neuroticism, although effect sizes were small. CONCLUSIONS: From two large cohort studies, our findings suggest intelligence acts a protective factor in mitigating the effects of neuroticism on psychological distress. Intelligence does not confer protection against diagnosis of depression in those high in neuroticism
Kinetics of active surface-mediated diffusion in spherically symmetric domains
We present an exact calculation of the mean first-passage time to a target on
the surface of a 2D or 3D spherical domain, for a molecule alternating phases
of surface diffusion on the domain boundary and phases of bulk diffusion. We
generalize the results of [J. Stat. Phys. {\bf 142}, 657 (2011)] and consider a
biased diffusion in a general annulus with an arbitrary number of regularly
spaced targets on a partially reflecting surface. The presented approach is
based on an integral equation which can be solved analytically. Numerically
validated approximation schemes, which provide more tractable expressions of
the mean first-passage time are also proposed. In the framework of this minimal
model of surface-mediated reactions, we show analytically that the mean
reaction time can be minimized as a function of the desorption rate from the
surface.Comment: Published online in J. Stat. Phy
On the Lebesgue measure of Li-Yorke pairs for interval maps
We investigate the prevalence of Li-Yorke pairs for and
multimodal maps with non-flat critical points. We show that every
measurable scrambled set has zero Lebesgue measure and that all strongly
wandering sets have zero Lebesgue measure, as does the set of pairs of
asymptotic (but not asymptotically periodic) points.
If is topologically mixing and has no Cantor attractor, then typical
(w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally
admits an absolutely continuous invariant probability measure (acip), then
typical pairs have a dense orbit for . These results make use of
so-called nice neighborhoods of the critical set of general multimodal maps,
and hence uniformly expanding Markov induced maps, the existence of either is
proved in this paper as well.
For the setting where has a Cantor attractor, we present a trichotomy
explaining when the set of Li-Yorke pairs and distal pairs have positive
two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure
Possible origins of macroscopic left-right asymmetry in organisms
I consider the microscopic mechanisms by which a particular left-right (L/R)
asymmetry is generated at the organism level from the microscopic handedness of
cytoskeletal molecules. In light of a fundamental symmetry principle, the
typical pattern-formation mechanisms of diffusion plus regulation cannot
implement the "right-hand rule"; at the microscopic level, the cell's
cytoskeleton of chiral filaments seems always to be involved, usually in
collective states driven by polymerization forces or molecular motors. It seems
particularly easy for handedness to emerge in a shear or rotation in the
background of an effectively two-dimensional system, such as the cell membrane
or a layer of cells, as this requires no pre-existing axis apart from the layer
normal. I detail a scenario involving actin/myosin layers in snails and in C.
elegans, and also one about the microtubule layer in plant cells. I also survey
the other examples that I am aware of, such as the emergence of handedness such
as the emergence of handedness in neurons, in eukaryote cell motility, and in
non-flagellated bacteria.Comment: 42 pages, 6 figures, resubmitted to J. Stat. Phys. special issue.
Major rewrite, rearranged sections/subsections, new Fig 3 + 6, new physics in
Sec 2.4 and 3.4.1, added Sec 5 and subsections of Sec
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