247 research outputs found
Teaching case: Headache stigmata
A 38-year-old man with past medical history of hypertension and obesity presented to our clinic for evaluation of severe headaches and multiple episodes of discoloration of the forehead on the same side as the headache
Swings and roundabouts: the vagaries of democratic consolidation and ‘electoral rituals’ in Sierra Leone
YesThe history of the electoral process in Sierra Leone is at the same time tortuous and substantial. From relatively open competitive multi-party politics in the 1960s, which led to the first turnover of power at the ballot box, through the de facto and de jure one-party era, which nonetheless had elements of electoral competition, and finally to contemporary post-conflict times, which has seen three elections and a second electoral turnover in 2007, one can discern evolving patterns. Evidence from the latest local and national elections in 2012 suggests that there is some democratic consolidation, at least in an electoral sense. However, one might also see simultaneous steps forward and backward – What you gain on the swings, you may lose on the roundabouts. This is particularly so in terms of institutional capacities, fraud and violence, and one would need to enquire of the precise ingredients – in terms of political culture or in other words the attitudes and motivations of electors and the elected – of this evolving Sierra Leonean, rather than specifically liberal type, of democracy. Equally, the development of ‘electoral rituals’, whether peculiar to Sierra Leone or not and whether deemed consolidatory or not, has something to say as part of an investigation into the electoral element of democratic consolidation.1 The literature on elections in Africa most often depicts a number of broad features, such as patronage, ethno-regionalism, fraud and violence, and it is the intention of this article to locate contemporary Sierra Leone, as precisely as possible, within the various strands of this discourse
Self-diffusion in dense granular shear flows
Diffusivity is a key quantity in describing velocity fluctuations in granular
materials. These fluctuations are the basis of many thermodynamic and
hydrodynamic models which aim to provide a statistical description of granular
systems. We present experimental results on diffusivity in dense, granular
shear in a 2D Couette geometry. We find that self-diffusivities are
proportional to the local shear rate with diffusivities along the mean flow
approximately twice as large as those in the perpendicular direction. The
magnitude of the diffusivity is D \approx \dot\gamma a^2 where a is the
particle radius. However, the gradient in shear rate, coupling to the mean
flow, and drag at the moving boundary lead to particle displacements that can
appear sub- or super-diffusive. In particular, diffusion appears superdiffusive
along the mean flow direction due to Taylor dispersion effects and subdiffusive
along the perpendicular direction due to the gradient in shear rate. The
anisotropic force network leads to an additional anisotropy in the diffusivity
that is a property of dense systems with no obvious analog in rapid flows.
Specifically, the diffusivity is supressed along the direction of the strong
force network. A simple random walk simulation reproduces the key features of
the data, such as the apparent superdiffusive and subdiffusive behavior arising
from the mean flow, confirming the underlying diffusive motion. The additional
anisotropy is not observed in the simulation since the strong force network is
not included. Examples of correlated motion, such as transient vortices, and
Levy flights are also observed. Although correlated motion creates velocity
fields qualitatively different from Brownian motion and can introduce
non-diffusive effects, on average the system appears simply diffusive.Comment: 13 pages, 20 figures (accepted to Phys. Rev. E
Disk, merger, or outflow ? Molecular gas kinematics in two powerful obscured QSOs at z>3.4
We report on the detection of bright CO(4-3) line emission in two powerful,
obscured quasars discovered in the SWIRE survey, SW022513 and SW022550 at
z>3.4. We analyze the line strength and profile to determine the gas mass,
dynamical mass and the gas dynamics for both galaxies. In SW022513 we may have
found the first evidence for a molecular, AGN-driven wind in the early
Universe. The line profile in SW022513 is broad (FWHM = 1000 km/s) and
blueshifted by -200 km/s relative to systemic (where the systemic velocity is
estimated from the narrow components of ionized gas lines, as is commonly done
for AGN at low and high redshifts). SW022550 has a more regular, double-peaked
profile, which is marginally spatially resolved in our data, consistent with
either a merger or an extended disk. The molecular gas masses, 4x10^10 Msun,
are large and account for <30% of the stellar mass, making these obscured QSOs
as gas rich as other powerful CO emitting galaxies at high redshift, i.e.,
submillimeter galaxies. Our sources exhibit relatively lower star-formation
efficiencies compared to other dusty, powerful starburst galaxies at high
redshift. We speculate that this could be a consequence of the AGN perturbing
the molecular gas.Comment: Accepted for publication in A&
Mental health in the pandemic: a repeated cross-sectional mixed-method study protocol to investigate the mental health impacts of the coronavirus pandemic in the UK.
Funder: MQ: Transforming Mental Health; Grant(s): MQBF/3INTRODUCTION: The WHO declared a global pandemic on 11 March 2020. Since then, the world has been firmly in the grip of the COVID-19. To date, more than 211 730 035 million confirmed cases and more than 4 430 697 million people have died. While controlling the virus and implementing vaccines are the main priorities, the population mental health impacts of the pandemic are expected to be longer term and are less obvious than the physical health ones. Lockdown restrictions, physical distancing, social isolation, as well as the loss of a loved one, working in a frontline capacity and loss of economic security may have negative effects on and increase the mental health challenges in populations around the world. There is a major demand for long-term research examining the mental health experiences and needs of people in order to design adequate policies and interventions for sustained action to respond to individual and population mental health needs both during and after the pandemic. METHODS AND ANALYSIS: This repeated cross-sectional mixed-method study conducts regular self-administered representative surveys, and targeted focus groups and semi-structured interviews with adults in the UK, as well as validation of gathered evidence through citizens' juries for contextualisation (for the UK as a whole and for its four devolved nations) to ensure that emerging mental health problems are identified early on and are properly understood, and that appropriate policies and interventions are developed and implemented across the UK and within devolved contexts. STATA and NVIVO will be used to carry out quantitative and qualitative analysis, respectively. ETHICS AND DISSEMINATION: Ethics approval for this study has been granted by the Cambridge Psychology Research Ethics Committee of the University of Cambridge, UK (PRE 2020.050) and by the Health and Life Sciences Research Ethics Committee of De Montfort University, UK (REF 422991). While unlikely, participants completing the self-administered surveys or participating in the virtual focus groups, semi-structured interviews and citizens' juries might experience distress triggered by questions or conversations. However, appropriate mitigating measures have been adopted and signposting to services and helplines will be available at all times. Furthermore, a dedicated member of staff will also be at hand to debrief following participation in the research and personalised thank-you notes will be sent to everyone taking part in the qualitative research.Study findings will be disseminated in scientific journals, at research conferences, local research symposia and seminars. Evidence-based open access briefings, articles and reports will be available on our study website for everyone to access. Rapid policy briefings targeting issues emerging from the data will also be disseminated to inform policy and practice. These briefings will position the findings within UK public policy and devolved nations policy and socioeconomic contexts in order to develop specific, timely policy recommendations. Additional dissemination will be done through traditional and social media. Our data will be contextualised in view of existing policies, and changes over time as-and-when policies change
Safety in numbers: mathematics support centres and their derivatives as social learning spaces
Stop looking angry and smile, please: start and stop of the very same facial expression differentially activate threat- and reward-related brain networks
Static pictures of emotional facial expressions have been found to activate brain structures involved in the processing of emotional stimuli. However, in everyday live, emotional expressions are changing rapidly, and the processing of the onset vs the offset of the very same emotional expression might rely on different brain networks, presumably leading to different behavioral and physiological reactions (e.g. approach or avoidance). Using functional magnetic resonance imaging, this was examined by presenting video clips depicting onsets and offsets of happy and angry facial expressions. Subjective valence and threat ratings clearly depended on the direction of change. Blood oxygen level dependent responses indicate both reward- and threat-related activations for the offset of angry expressions. Comparing onsets and offsets, angry offsets were associated with stronger ventral striatum activation than angry onsets. Additionally, the offset of happy and the onset of angry expressions showed strong common activity in the lateral orbitofrontal cortex bilaterally, the left amygdala and the left insula, whereas the onset of happy and the offset of angry expressions induced significant activation in the left dorsal striatum. In sum, the results confirm different activity in motivation-related brain areas in response to the onset and offset of the same emotional expression and highlight the importance of temporal characteristics of facial expressions for social communication
Language, Religion, and Ethnic Civil War
Are certain ethnic cleavages more conflict-prone than others? While only few scholars focus on the contents of ethnicity, most of those who do argue that political violence is more likely to occur along religious divisions than linguistic ones. We challenge this claim by analyzing the path from linguistic differences to ethnic civil war along three theoretical steps: (1) the perception of grievances by group members, (2) rebel mobilization, and (3) government accommodation of rebel demands. Our argument is tested with a new data set of ethnic cleavages that records multiple linguistic and religious segments for ethnic groups from 1946 to 2009. Adopting a relational perspective, we assess ethnic differences between potential challengers and the politically dominant group in each country. Our findings indicate that intrastate conflict is more likely within linguistic dyads than among religious ones. Moreover, we find no support for the thesis that Muslim groups are particularly conflict-prone
Spintronics: Fundamentals and applications
Spintronics, or spin electronics, involves the study of active control and
manipulation of spin degrees of freedom in solid-state systems. This article
reviews the current status of this subject, including both recent advances and
well-established results. The primary focus is on the basic physical principles
underlying the generation of carrier spin polarization, spin dynamics, and
spin-polarized transport in semiconductors and metals. Spin transport differs
from charge transport in that spin is a nonconserved quantity in solids due to
spin-orbit and hyperfine coupling. The authors discuss in detail spin
decoherence mechanisms in metals and semiconductors. Various theories of spin
injection and spin-polarized transport are applied to hybrid structures
relevant to spin-based devices and fundamental studies of materials properties.
Experimental work is reviewed with the emphasis on projected applications, in
which external electric and magnetic fields and illumination by light will be
used to control spin and charge dynamics to create new functionalities not
feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes
from the published versio
Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man
notes: PMCID: PMC3887257This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development.Wellcome TrustDiabetes UKEuropean Community’s Seventh Framework Programme (FP7/2007-2013
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