The search for dark matter annihilation in galaxy clusters at VERITAS

Recent data and cosmological models point to a significant fraction of the Universe being comprised of Cold Dark Matter (DM), though little is known about it directly as it does not interact electromagnetically. The most likely explanation for DM is a Weakly Interacting Massive Particle (WIMP) having a mass as low as ∼10 GeV to as high as ∼10 TeV. WIMPs are believed to be their own antiparticles and self-annihilate into a variety of lighter particles including γ-rays. Many direct detection, indirect detection, and direct production schemes have been proposed to search for the elusive WIMP. Galaxy clusters, consisting of hundreds to thousands of galaxies, are the largest collections of matter in the Universe held together by gravity. As such, galaxy clusters also contain the highest concentrations of DM found anywhere. This thesis presents results on the VERITAS observations of 12 galaxy clusters selected from archival data. We seek to detect the γ-rays originating from the DM interactions within galaxy clusters. We calculate astrophysical J-factors for each of the galaxy clusters six of which had no prior J-factors with the DM simulations package CLUMPY. Since a DM detection is not made, the limit to the thermally-averaged DM annihilation velocity-weighted cross-section is then computed from the γ-ray flux upper limit. We employ a stacking method to combine the limits of the 12 galaxy clusters. The limits from the stacking method are found to be less constraining than some individual galaxy clusters due to the wide range of limits considered. We conclude that a larger number of galaxy clusters in the stacking method will yield more competitive limits to other DM searches

Adipocytes cause leukemia cell resistance to daunorubicin via oxidative stress response.

Adipocytes promote cancer progression and impair treatment, and have been shown to protect acute lymphoblastic leukemia (ALL) cells from chemotherapies. Here we investigate whether this protection is mediated by changes in oxidative stress. Co-culture experiments showed that adipocytes protect ALL cells from oxidative stress induced by drugs or irradiation. We demonstrated that ALL cells induce intracellular ROS and an oxidative stress response in adipocytes. This adipocyte oxidative stress response leads to the secretion of soluble factors which protect ALL cells from daunorubicin (DNR). Collectively, our investigation shows that ALL cells elicit an oxidative stress response in adipocytes, leading to adipocyte protection of ALL cells against DNR

Consumer Preferences Among Low-Price Guarantee Offers

The competitive realities of the marketplace forces retailers to consider implementing low-price guarantees. Given that retailers will use low-price guarantees, which of the multitude of guarantees should be used? This paper examines the nature of low-price guarantees from the perspective of how consumers make trade-offs in different low-price guarantee designs. Using conjoint analysis, buyers indicate their preference for different low-price guarantee designs. Not all consumers respond to low-price guarantees the same. There are several segments of consumers with regard to low-price guarantees. The study was done with young adults (MBA students) who may be more sophisticated than the population as a whole. Retailers choosing a low-price guarantee ought to understand the preferences among their customers in order to choose an optimal strategy

Confiabilidade da Avaliação da Orientação e Posição de Repouso da Escápula de Indivíduos Saudáveis e Sedentários com o Sistema Eletromagnético de Aquisição de Dados

Electromagnetic systems for motion analysis are claimed as a precise technique for tracking position and orientation of human body segments. To date, reliability electromagnetic tracking was described only for the dynamic assessment of the scapula motion, and no reliability studies on its resting posture or positioning were found. The aim of this study was to analyze intra- and inter-session reliabilities and absolute errors of the scapular orientation and position at habitual resting posture in healthy individuals. Twenty-two shoulder symptom-free individuals non participants in professional or recreational sports activities involving upper extremities were volunteers in this study. The equipment used was 3SPACE Liberty system (Polhemus Inc.). The same examiner collected the kinematic data from subjects in two different sessions, with an interval from seven to ten days. Intraclass Correlation Coefficient (ICC2,1 and ICC2, k) and Standard Error of Measurement (SEM) were calculated. Inter-session reliability ranged from good to excellent (ICC from 0.66 to 0.96) and intra-session reliability was excellent (ICC ≥ 0.97). SEM values found for linear distances were smaller than 0.02 cm and scapular rotations ranged from 0.72° to 5.48°. Results of this study demonstrated that electromagnetic data acquisition of scapula habitual posture is a reliable tool for defining scapular position and orientation in sedentary shoulder symptom-free individuals.Sistemas eletromagnéticos para análise de movimento são conhecidos como precisos para registrar a posição e orientação dos segmentos do corpo humano. Até o momento, a confiabilidade do registro eletromagnético foi descrita apenas para a dinâmica da escápula, não sendo encontrados estudos de confiabilidade da posição de repouso ou postura da mesma. O objetivo deste estudo foi a análise da confiabilidade intra- e inter-sessão e erros absolutos do registro eletromagnético da posição e orientação da escápula na postura habitual de repouso de indivíduos saudáveis. Foram voluntários no estudo 22 indivíduos sem sintomas no complexo articular do ombro e não-praticantes amadores ou profissionais de esporte e atividade física envolvendo os membros superiores. O equipamento utilizado foi o sistema 3SPACE Liberty (Polhemus Inc.). Um mesmo avaliador coletou os dados cinemáticos em duas sessões diferentes com um intervalo de sete a dez dias. O Coeficiente de Correlação Intraclasse (ICC2,1 e ICC2,k) e o Erro Padrão de Medida (EPM) foram calculados. A confiabilidade inter-sessão variou entre boa a excelente (ICC de 0,66 a 0,96) e a confiabilidade intra-sessão foi sempre excelente (ICC ≥ 0,97). Os valores de EPM encontrados para as distâncias lineares foram menores que 0,02 cm e para as rotações da escápula relativa ao tórax variaram entre 0,72 º e 5,48 º. Os resultados deste estudo demonstraram que o registro eletromagnético da posição habitual de repouso da escápula é confiável para determinar a posição e a orientação da mesma em um população sedentária e sem sintomas no complexo articular do ombro.University of São Paulo School of Medicine of Ribeirão Preto Department of PhysiotherapyFederal University of São Paulo Department of Human Movement ScienceUniversity of Washington Division of Physical Therapy School of MedicineUNIFESP, Department of Human Movement ScienceSciEL

Bilateral Distal Radius Fractures in a 12-Year-Old Boy after Household Electrical Shock: Case Report and Literature Summary

Background. Fracture resulting from household electric shock is uncommon. When it occurs, it is usually the result of a fall; however, electricity itself can cause sufficient tetany to produce a fracture. We present the case of bilateral fractures of the distal radii of a 12-year-old boy which were sustained after accidental shock. The literature regarding fractures after domestic electric shock is also reviewed. Methods. An Ovid-Medline search was conducted. The resultant articles and their bibliographies were surveyed for cases describing fractures resulting from a typical household-level voltage (110–220 V, 50–60 Hertz) and not a fall after the shock. Twenty-one articles describing 22 patients were identified. Results. Twenty-two cases were identified. Thirteen were unilateral injuries; 9 were bilateral. Proximal humerus fractures were most frequent (8 cases), followed by scapula fractures (7 cases), forearm fractures (4 cases), femoral neck fractures (2 cases), and vertebral body fracture (1 case). Eight of the 22 cases were diagnosed days to weeks after the injury. Conclusions. Fracture after electric shock is uncommon. It should be suspected in patients with persistent pain, particularly in the shoulder or forearm area. Distal radius fractures that occur during electrocution are likely due to tetany

Accretion of Planetary Material onto Host Stars

Accretion of planetary material onto host stars may occur throughout a star's life. Especially prone to accretion, extrasolar planets in short-period orbits, while relatively rare, constitute a significant fraction of the known population, and these planets are subject to dynamical and atmospheric influences that can drive significant mass loss. Theoretical models frame expectations regarding the rates and extent of this planetary accretion. For instance, tidal interactions between planets and stars may drive complete orbital decay during the main sequence. Many planets that survive their stars' main sequence lifetime will still be engulfed when the host stars become red giant stars. There is some observational evidence supporting these predictions, such as a dearth of close-in planets around fast stellar rotators, which is consistent with tidal spin-up and planet accretion. There remains no clear chemical evidence for pollution of the atmospheres of main sequence or red giant stars by planetary materials, but a wealth of evidence points to active accretion by white dwarfs. In this article, we review the current understanding of accretion of planetary material, from the pre- to the post-main sequence and beyond. The review begins with the astrophysical framework for that process and then considers accretion during various phases of a host star's life, during which the details of accretion vary, and the observational evidence for accretion during these phases.Comment: 18 pages, 5 figures (with some redacted), invited revie

A measurement of the millimetre emission and the Sunyaev-Zel'dovich effect associated with low-frequency radio sources

We present a statistical analysis of the millimetre-wavelength properties of 1.4GHz-selected sources and a detection of the Sunyaev–Zel’dovich (SZ) effect associated with the haloes that host them. We stack data at 148, 218 and 277GHz from the Atacama Cosmology Telescope at the positions of a large sample of radio AGN selected at 1.4GHz. The thermal SZ effect associated with the haloes that host the AGN is detected at the 5σ level through its spectral signature, representing a statistical detection of the SZ effect in some of the lowest mass haloes (average M 200 ≈ 10 13 M. h −1 70 ) studied to date. The relation between the SZ effect and mass (based on weak lensing measurements of radio galaxies) is consistent with that measured by Planck for local bright galaxies. In the context of galaxy evolution models, this study confirms that galaxies with radio AGN also typically support hot gaseous haloes. Adding Herschel observations allows us to show that the SZ signal is not significantly contaminated by dust emission. Finally, we analyse the contribution of radio sources to the angular power spectrum of the cosmic microwave background

Whole genome sequencing for the diagnosis of neurological repeat expansion disorders in the UK: a retrospective diagnostic accuracy and prospective clinical validation study

BACKGROUND: Repeat expansion disorders affect about 1 in 3000 individuals and are clinically heterogeneous diseases caused by expansions of short tandem DNA repeats. Genetic testing is often locus-specific, resulting in underdiagnosis of people who have atypical clinical presentations, especially in paediatric patients without a previous positive family history. Whole genome sequencing is increasingly used as a first-line test for other rare genetic disorders, and we aimed to assess its performance in the diagnosis of patients with neurological repeat expansion disorders. METHODS: We retrospectively assessed the diagnostic accuracy of whole genome sequencing to detect the most common repeat expansion loci associated with neurological outcomes (AR, ATN1, ATXN1, ATXN2, ATXN3, ATXN7, C9orf72, CACNA1A, DMPK, FMR1, FXN, HTT, and TBP) using samples obtained within the National Health Service in England from patients who were suspected of having neurological disorders; previous PCR test results were used as the reference standard. The clinical accuracy of whole genome sequencing to detect repeat expansions was prospectively examined in previously genetically tested and undiagnosed patients recruited in 2013-17 to the 100 000 Genomes Project in the UK, who were suspected of having a genetic neurological disorder (familial or early-onset forms of ataxia, neuropathy, spastic paraplegia, dementia, motor neuron disease, parkinsonian movement disorders, intellectual disability, or neuromuscular disorders). If a repeat expansion call was made using whole genome sequencing, PCR was used to confirm the result. FINDINGS: The diagnostic accuracy of whole genome sequencing to detect repeat expansions was evaluated against 793 PCR tests previously performed within the NHS from 404 patients. Whole genome sequencing correctly classified 215 of 221 expanded alleles and 1316 of 1321 non-expanded alleles, showing 97·3% sensitivity (95% CI 94·2-99·0) and 99·6% specificity (99·1-99·9) across the 13 disease-associated loci when compared with PCR test results. In samples from 11 631 patients in the 100 000 Genomes Project, whole genome sequencing identified 81 repeat expansions, which were also tested by PCR: 68 were confirmed as repeat expansions in the full pathogenic range, 11 were non-pathogenic intermediate expansions or premutations, and two were non-expanded repeats (16% false discovery rate). INTERPRETATION: In our study, whole genome sequencing for the detection of repeat expansions showed high sensitivity and specificity, and it led to identification of neurological repeat expansion disorders in previously undiagnosed patients. These findings support implementation of whole genome sequencing in clinical laboratories for diagnosis of patients who have a neurological presentation consistent with a repeat expansion disorder. FUNDING: Medical Research Council, Department of Health and Social Care, National Health Service England, National Institute for Health Research, and Illumina

Truncating mutations in SPAST patients are associated with a high rate of psychiatric comorbidities in hereditary spastic paraplegia.

BACKGROUND: The hereditary spastic paraplegias (HSPs) are a rare and heterogeneous group of neurodegenerative disorders that are clinically characterised by progressive lower limb spasticity. They are classified as either 'pure' or 'complex' where spastic paraplegia is complicated with additional neurological features. Mutations in the spastin gene (SPAST) are the most common cause of HSP and typically present with a pure form. METHODS: We assessed in detail the phenotypic and genetic spectrum of SPAST-related HSP focused on 118 patients carrying SPAST mutations. RESULTS: This study, one of the largest cohorts of genetically confirmed spastin patients to date, contributes with the discovery of a significant number of novel SPAST mutations. Our data reveal a high rate of complex cases (25%), with psychiatric disorders among the most common comorbidity (10% of all SPASTpatients). Further, we identify a genotype-phenotype correlation between patients carrying loss-of-function mutations in SPAST and the presence of psychiatric disorders