1,165 research outputs found
Institutions and Elites: Democracy and Stability in sub-Saharan Africa
Sub-Saharan Africa is one of the most politically unstable and undemocratic regions in the world. Theories of power-sharing and recent studies have indicated that institutions that allow for higher levels of power-sharing are often more successful at consolidating democracy and stability in highly divided societies, like those common in Sub-Saharan Africa. By examining the electoral system, executive type, and level of decentralization, this study first determines the level of institutional power-sharing for each of the 48 sub-Saharan states. Next, it compares these levels of power-sharing with indicators of democracy and state stability to determine if more power-sharing does correspond with higher levels of democracy and stability. Using a bivariate analysis and factoring in region, the data show a strong and significant correlation between higher levels of institutional power-sharing and higher levels of democracy and state stability in sub-Saharan Africa. However, power-sharing does not appear to be a necessary or sufficient driver of democratic outcomes. In order to better determine the nature of the relationship between institutional design and contextual factors, the later part of the study employs a focused-structured most-similar comparison between Ghana and Cote dâIvoire, countries with identical and moderately low power-sharing scores but drastically different levels of democracy and state stability
Barriers, control and identity in health information seeking among African American women
Qualitative research methods were used to examine the role of racial, cultural, and socio-economic group (i.e., communal) identities on perceptions of barriers and control related to traditional and internet resources for seeking health information. Eighteen lower income, African American women participated in training workshops on using the internet for health, followed by two focus groups. Transcripts were analyzed using standardized coding methods. Results demonstrated that participants perceived the internet as a tool for seeking health information, which they believed would empower them within formal healthcare settings. Participants invoked racial, cultural, and socio-economic identities when discussing barriers to seeking health information within healthcare systems and the internet. The findings indicate that the internet may be a valuable tool for accessing health information among lower income African American women if barriers are reduced. Recommendations are made that may assist health providers in improving health information seeking outcomes of African American women
Comment on Higgs Inflation and Naturalness
We rebut the recent claim (arXiv:0912.5463) that Einstein-frame scattering in
the Higgs inflation model is unitary above the cut-off energy Lambda ~ Mp/xi.
We show explicitly how unitarity problems arise in both the Einstein and Jordan
frames of the theory. In a covariant gauge they arise from non-minimal Higgs
self-couplings, which cannot be removed by field redefinitions because the
target space is not flat. In unitary gauge, where there is only a single scalar
which can be redefined to achieve canonical kinetic terms, the unitarity
problems arise through non-minimal Higgs-gauge couplings.Comment: 5 pages, 1 figure V3: Journal Versio
Treating Imatinib-Resistant Leukemia: The Next Generation Targeted Therapies
Imatinib (Gleevec/STI-571/CGP57148B, Novartis) is a small-molecule, tyrosine kinase inhibitor developed to target BCR-ABL, c-Kit, and PDGF-R. Through inhibition of these oncogenic kinases, imatinib is effective in the treatment of BCR-ABLpositive leukemia, gastrointestinal stromal tumor, and hypereosinophilic syndrome, respectively. However, clinical success of imatinib is hampered by acquired resistance that may occur through several mechanisms including kinase domain mutation, target amplification, and activation of alternate signaling pathways. Strategies to overcome resistance have included targeting BCR-ABL stability and downstream signaling pathways important for tumor growth. Additional work has shown that new BCR-ABL kinase inhibitors with increased potency or alternate conformation-binding properties can target imatinib resistance. This review focuses on the mechanisms of imatinib resistance and the strategies currently being developed to overcome clinical resistance
Using Early Data to Illuminate the Pioneer Anomaly
Analysis of the radio tracking data from the Pioneer 10/11 spacecraft at
distances between about 20 - 70 AU from the Sun has consistently indicated the
presence of an unmodeled, small, constant, Doppler blue shift drift of order 6
\times 10^{-9} Hz/s. After accounting for systematics, this drift can be
interpreted as a constant acceleration of a_P= (8.74 \pm 1.33) \times 10^{-8}
cm/s^2 directed towards the Sun, or perhaps as a time acceleration of a_t =
(2.92 \pm 0.44)\times 10^{-18} s/s^2. Although it is suspected that there is a
systematic origin to this anomaly, none has been unambiguously demonstrated. We
review the current status of the anomaly, and then point out how the analysis
of early data, which was never analyzed in detail, could allow a more clear
understanding of the origin of the anomaly, be it a systematic or a
manifestation of unsuspected physics.Comment: 19 pages, 6 figures, 2 tables, additional materia
The Universal Kaehler Modulus in Warped Compactifications
We construct the effective theory of the universal Kaehler modulus in warped
compactifications using the Hamiltonian formulation of general relativity. The
spacetime dependent 10d solution is constructed at the linear level for both
the volume modulus and its axionic partner, and nontrivial cancellations of
warping effects are found in the dimensional reduction. Our main result is that
the Kaehler potential is not corrected by warping, up to an overall shift in
the background value of the volume modulus. We extend the analysis beyond the
linearized approximation by computing the fully backreacted 10d metric
corresponding to a finite volume modulus fluctuation. Also, we discuss the
behavior of the modulus in strongly warped regions and show that there are no
mixings with light Kaluza-Klein modes. These results are important for the
phenomenology and cosmology of flux compactifications.Comment: 28 pages, 1 figure; v2. corrected typos, added refs & minor
clarification
Lost in spatial translation - A novel tool to objectively assess spatial disorientation in Alzheimer's disease and frontotemporal dementia
Spatial disorientation is a prominent feature of early Alzheimer's disease (AD) attributed to degeneration of medial temporal and parietal brain regions, including the retrosplenial cortex (RSC). By contrast, frontotemporal dementia (FTD) syndromes show generally intact spatial orientation at presentation. However, currently no clinical tasks are routinely administered to objectively assess spatial orientation in these neurodegenerative conditions. In this study we investigated spatial orientation in 58 dementia patients and 23 healthy controls using a novel virtual supermarket task as well as voxel-based morphometry (VBM). We compared performance on this task with visual and verbal memory function, which has traditionally been used to discriminate between AD and FTD. Participants viewed a series of videos from a first person perspective travelling through a virtual supermarket and were required to maintain orientation to a starting location. Analyses revealed significantly impaired spatial orientation in AD, compared to FTD patient groups. Spatial orientation performance was found to discriminate AD and FTD patient groups to a very high degree at presentation. More importantly, integrity of the RSC was identified as a key neural correlate of orientation performance. These findings confirm the notion that i) it is feasible to assess spatial orientation objectively via our novel Supermarket task; ii) impaired orientation is a prominent feature that can be applied clinically to discriminate between AD and FTD and iii) the RSC emerges as a critical biomarker to assess spatial orientation deficits in these neurodegenerative conditions
Associations between post-traumatic stress disorders and psychotic symptom severity in adult survivors of developmental trauma: a multisite cross-sectional study in the UK and South Korea
BACKGROUND: Childhood maltreatment is a risk factor for the development of post-traumatic stress disorders and psychosis. However, the association between post-traumatic stress disorder (PTSD), including complex PTSD, and psychotic symptoms is unknown. We investigated whether the presence of PTSD and complex PTSD was associated with psychotic symptom severity within survivors of developmental trauma. METHODS: As part of the Investigating Mechanisms underlying Psychosis Associated with Childhood Trauma (IMPACT) study, from Aug 20, 2020, to Jan 24, 2021, and from Sept 9, 2022, to Feb 21, 2023, using study advertisement on online platforms we recruited adult (â„18 years) participants who had experienced developmental trauma without a psychiatric diagnosis in the UK and South Korea. We measured whether participants met diagnostic thresholds for PTSD and complex PTSD using the self-reported International Trauma Questionnaire, and psychotic symptoms using the self-reported Community Assessment of Psychic Experiences. We used linear regression, adjusting for sociodemographic variables such as age, sex, ethnicity, educational attainment, and socioeconomic status, to examine whether there was an association between PTSD and complex PTSD and psychotic symptoms. The study is registered in the UK (University College London Research Ethics Committee [14317/001] and the National Health Service Research Ethics Committee [22/YH/0096]) and South Korea (Institutional Review Board of Seoul National University Bundang Hospital [B-2011-648-306]), and is ongoing. FINDINGS: Of the 2675 participants who took part in the study, 1273 had experienced developmental trauma and were included in the study in the UK (n=475) and South Korea (n=798), comprising 422 (33%) men and 851 (67%) women with a mean age of 26·9 years (SD 6, range 18-40), mostly of White British (n=328) or South Korean (n=798) ethnicity. We found no significant association between PTSD and psychotic symptom severity (total severity ÎČ=-2·40 [SE 3·28], p=0·47), compared with participants who did not meet PTSD or complex PTSD caseness. We found a significant relationship between complex PTSD and psychotic symptom severity (total severity ÎČ=22·62 [SE 1·65], p<0·0001), including for positive (ÎČ=12·07 [SE 0·99], p<0·0001) and negative symptoms (ÎČ=10·5 [SE 0·95], p<0·0001), compared with participants who did not meet PTSD or complex PTSD caseness. INTERPRETATION: Health systems must assess individuals with previous developmental trauma for complex PTSD and treat those affected. These individuals should also be assessed for psychotic symptoms, and if necessary, preventative measures should be taken to reduce risk of conversion. Further work should assess whether treating complex PTSD modifies the risk of conversion to psychosis. FUNDING: UKRI Future Leaders Fellowship, British Medical Association Margaret Temple Award for Schizophrenia Research, and the National Research Foundation of Korea-Korea Government
A comparison of magnetic resonance imaging and neuropsychological examination in the diagnostic distinction of Alzheimerâs disease and behavioral variant frontotemporal dementia
The clinical distinction between Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) remains challenging and largely dependent on the experience of the clinician. This study investigates whether objective machine learning algorithms using supportive neuroimaging and neuropsychological clinical features can aid the distinction between both diseases. Retrospective neuroimaging and neuropsychological data of 166 participants (54 AD; 55 bvFTD; 57 healthy controls) was analyzed via a NaĂŻve Bayes classification model. A subgroup of patients (n = 22) had pathologically-confirmed diagnoses. Results show that a combination of gray matter atrophy and neuropsychological features allowed a correct classification of 61.47% of cases at clinical presentation. More importantly, there was a clear dissociation between imaging and neuropsychological features, with the latter having the greater diagnostic accuracy (respectively 51.38 vs. 62.39%). These findings indicate that, at presentation, machine learning classification of bvFTD and AD is mostly based on cognitive and not imaging features. This clearly highlights the urgent need to develop better biomarkers for both diseases, but also emphasizes the value of machine learning in determining the predictive diagnostic features in neurodegeneration
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