Constraints on Low-Mass WIMP Interactions on 19F from PICASSO

Recent results from the PICASSO dark matter search experiment at SNOLAB are reported. These results were obtained using a subset of 10 detectors with a total target mass of 0.72 kg of 19F and an exposure of 114 kgd. The low backgrounds in PICASSO allow recoil energy thresholds as low as 1.7 keV to be obtained which results in an increased sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs) with masses below 10 GeV/c^2. No dark matter signal was found. Best exclusion limits in the spin dependent sector were obtained for WIMP masses of 20 GeV/c^2 with a cross section on protons of sigma_p^SD = 0.032 pb (90% C.L.). In the spin independent sector close to the low mass region of 7 GeV/c2 favoured by CoGeNT and DAMA/LIBRA, cross sections larger than sigma_p^SI = 1.41x10^-4 pb (90% C.L.) are excluded.Comment: 23 pages, 7 figures, to be published in Phys. Lett.

Hydroxyurea is associated with lower prevalence of albuminuria in adults with sickle cell disease

Albuminuria is an early manifestation of sickle cell nephropathy. Prior small case series suggests benefit of hydroxyurea in reducing albuminuria, with a similar trend noted in pediatric studies. We aimed to comprehensively evaluate hydroxyurea use and prevalence of albuminuria in adult sickle cell patients

Serotonin and corticosterone rhythms in mice exposed to cigarette smoke and in patients with COPD:implication for COPD-associated neuropathogenesis

The circadian timing system controls daily rhythms of physiology and behavior, and disruption of clock function can trigger stressful life events. Daily exposure to cigarette smoke (CS) can lead to alteration in diverse biological and physiological processes. Smoking is associated with mood disorders, including depression and anxiety. Patients with chronic obstructive pulmonary disease (COPD) have abnormal circadian rhythms, reflected by daily changes in respiratory symptoms and lung function. Corticosterone (CORT) is an adrenal steroid that plays a considerable role in stress and anti-inflammatory responses. Serotonin (5-hydroxytryptamine; 5HT) is a neurohormone, which plays a role in sleep/wake regulation and affective disorders. Secretion of stress hormones (CORT and 5HT) is under the control of the circadian clock in the suprachiasmatic nucleus. Since smoking is a contributing factor in the development of COPD, we hypothesize that CS can affect circadian rhythms of CORT and 5HT secretion leading to sleep and mood disorders in smokers and patients with COPD. We measured the daily rhythms of plasma CORT and 5HT in mice following acute (3 d), sub-chronic (10 d) or chronic (6 mo) CS exposure and in plasma from non-smokers, smokers and patients with COPD. Acute and chronic CS exposure affected both the timing (peak phase) and amplitude of the daily rhythm of plasma CORT and 5HT in mice. Acute CS appeared to have subtle time-dependent effects on CORT levels but more pronounced effects on 5HT. As compared with CORT, plasma 5HT was slightly elevated in smokers but was reduced in patients with COPD. Thus, the effects of CS on plasma 5HT were consistent between mice and patients with COPD. Together, these data reveal a significant impact of CS exposure on rhythms of stress hormone secretion and subsequent detrimental effects on cognitive function, depression-like behavior, mood/anxiety and sleep quality in smokers and patients with COPD

Human MC4R variants affect endocytosis, trafficking and dimerization revealing multiple cellular mechanisms involved in weight regulation.

The Melanocortin-4 Receptor (MC4R) plays a pivotal role in energy homeostasis. We used human MC4R mutations associated with an increased or decreased risk of obesity to dissect mechanisms that regulate MC4R function. Most obesity-associated mutations impair trafficking to the plasma membrane (PM), whereas obesity-protecting mutations either accelerate recycling to the PM or decrease internalization, resulting in enhanced signaling. MC4R mutations that do not affect canonical Gαs protein-mediated signaling, previously considered to be non-pathogenic, nonetheless disrupt agonist-induced internalization, β-arrestin recruitment, and/or coupling to Gαs, establishing their causal role in severe obesity. Structural mapping reveals ligand-accessible sites by which MC4R couples to effectors and residues involved in the homodimerization of MC4R, which is disrupted by multiple obesity-associated mutations. Human genetic studies reveal that endocytosis, intracellular trafficking, and homodimerization regulate MC4R function to a level that is physiologically relevant, supporting the development of chaperones, agonists, and allosteric modulators of MC4R for weight loss therapy

Changes in Cognition and Mortality in Relation to Exercise in Late Life: A Population Based Study

BACKGROUND: On average, cognition declines with age but this average hides considerable variability, including the chance of improvement. Here, we investigate how exercise is associated with cognitive change and mortality in older people and, particularly, whether exercise might paradoxically increase the risk of dementia by allowing people to live longer. METHODS AND PRINCIPAL FINDINGS: In the Canadian Study of Health and Aging (CSHA), of 8403 people who had baseline cognition measured and exercise reported at CSHA-1, 2219 had died and 5376 were re-examined at CSHA-2. We used a parametric Markov chain model to estimate the probabilities of cognitive improvement, decline, and death, adjusted for age and education, from any cognitive state as measured by the Modified Mini-Mental State Examination. High exercisers (at least three times per week, at least as intense as walking, n = 3264) had more frequent stable or improved cognition (42.3%, 95% confidence interval: 40.6-44.0) over 5 years than did low/no exercisers (all other exercisers and non exercisers, n = 4331) (27.8% (95% CI 26.4-29.2)). The difference widened as baseline cognition worsened. The proportion whose cognition declined was higher amongst the high exercisers but was more similar between exercise groups (39.4% (95% CI 37.7-41.1) for high exercisers versus 34.8% (95% CI 33.4-36.2) otherwise). People who did not exercise were also more likely to die (37.5% (95% CI 36.0-39.0) versus 18.3% (95% CI 16.9-19.7)). Even so, exercise conferred its greatest mortality benefit to people with the highest baseline cognition. CONCLUSIONS: Exercise is strongly associated with improving cognition. As the majority of mortality benefit of exercise is at the highest level of cognition, and declines as cognition declines, the net effect of exercise should be to improve cognition at the population level, even with more people living longer

Determining the bubble nucleation efficiency of low-energy nuclear recoils in superheated C3_3F8_8 dark matter detectors

The bubble nucleation efficiency of low-energy nuclear recoils in superheated liquids plays a crucial role in interpreting results from direct searches for weakly interacting massive particle (WIMP) dark matter. The PICO Collaboration presents the results of the efficiencies for bubble nucleation from carbon and fluorine recoils in superheated C$_3$F$_8$ from calibration data taken with 5 distinct neutron spectra at various thermodynamic thresholds ranging from 2.1 keV to 3.9 keV. Instead of assuming any particular functional forms for the nuclear recoil efficiency, a generalized piecewise linear model is proposed with systematic errors included as nuisance parameters to minimize model-introduced uncertainties. A Markov-Chain Monte-Carlo (MCMC) routine is applied to sample the nuclear recoil efficiency for fluorine and carbon at 2.45 keV and 3.29 keV thermodynamic thresholds simultaneously. The nucleation efficiency for fluorine was found to be $\geq 50\, \%$ for nuclear recoils of 3.3 keV (3.7 keV) at a thermodynamic Seitz threshold of 2.45 keV (3.29 keV), and for carbon the efficiency was found to be $\geq 50\, \%$ for recoils of 10.6 keV (11.1 keV) at a threshold of 2.45 keV (3.29 keV). Simulated data sets are used to calculate a p-value for the fit, confirming that the model used is compatible with the data. The fit paradigm is also assessed for potential systematic biases, which although small, are corrected for. Additional steps are performed to calculate the expected interaction rates of WIMPs in the PICO-60 detector, a requirement for calculating WIMP exclusion limits.Comment: 17 pages, 22 figures, 5 table

Search for inelastic dark matter-nucleus scattering with the PICO-60 CF3_{3}I and C3_{3}F8_{8} bubble chambers

PICO bubble chambers have exceptional sensitivity to inelastic dark matter-nucleus interactions due to a combination of their extended nuclear recoil energy detection window from a few keV to $O$(100 keV) or more and the use of iodine as a heavy target. Inelastic dark matter-nucleus scattering is interesting for studying the properties of dark matter, where many theoretical scenarios have been developed. This study reports the results of a search for dark matter inelastic scattering with the PICO-60 bubble chambers. The analysis reported here comprises physics runs from PICO-60 bubble chambers using CF$_{3}$I and C$_{3}$F$_{8}$. The CF$_{3}$I run consisted of 36.8 kg of CF$_{3}$I reaching an exposure of 3415 kg-day operating at thermodynamic thresholds between 7 and 20 keV. The C$_{3}$F$_{8}$ runs consisted of 52 kg of C$_{3}$F$_{8}$ reaching exposures of 1404 kg-day and 1167 kg-day running at thermodynamic thresholds of 2.45 keV and 3.29 keV, respectively. The analysis disfavors various scenarios, in a wide region of parameter space, that provide a feasible explanation of the signal observed by DAMA, assuming an inelastic interaction, considering that the PICO CF$_{3}$I bubble chamber used iodine as the target material.Comment: 7 pages, 3 figure

Dark Matter Search Results from the PICO-60C(3)F(8) Bubble Chamber

[EN] New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C3F8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C3F8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month. A blind analysis of an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4 x 10(-41) cm(2) for a 30-GeVc(-2) WIMP, more than 1 order of magnitude improvement from previous PICO results.The PICO Collaboration wishes to thank SNOLAB and its staff for support through underground space, logistical, and technical services. SNOLAB operations are supported by the Canada Foundation for Innovation and the Province of Ontario Ministry of Research and Innovation, with underground access provided by Vale at the Creighton mine site. We are grateful to Kristian Hahn and Stanislava Sevova of Northwestern University and Bjorn Penning of the University of Bristol for their assistance and useful discussion. We wish to acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI) for funding. We acknowledge the support from National Science Foundation (NSF) (Grants No. 0919526, No. 1506337, No. 1242637, and No. 1205987). We acknowledge that this work is supported by the U.S. Department of Energy (DOE) Office of Science, Office of High Energy Physics (under Award No. DE-SC-0012161), by a DOE Office of Science Graduate Student Research (SCGSR) award, by Direccion General Asuntos del Personal Academico, Universidad Nacional Autonoma de Mexico (DGAPA-UNAM) through the grant Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) No. IA100316 and by Consejo Nacional de Ciencia y Tecnologia (CONACyT) (Mexico) through Grant No. 252167, by the Department of Atomic Energy (DAE), the Government of India, under the Center of AstroParticle Physics II project (CAPP-II) at Saha Institute of Nuclear Physics (SINP), by the Czech Ministry of Education, Youth and Sports (Grant No. LM2015072), and by the Spanish Ministerio de Economia y Competitividad, Consolider MultiDark (Grant No. CSD2009-00064). This work is partially supported by the Kavli Institute for Cosmological Physics at the University of Chicago through NSF Grant No. 1125897, and an endowment from the Kavli Foundation and its founder Fred Kavli. We also wish to acknowledge the support from Fermi National Accelerator Laboratory under Contract No. De-AC02-07CH11359, and Pacific Northwest National Laboratory, which is operated by Battelle for the U.S. Department of Energy under Contract No. DE-AC05-76RL01830. We also thank Compute Canada and the Center for Advanced Computing, ACENET, Calcul Quebec, Compute Ontario, and WestGrid for the computational support.Amole, C.; Ardid Ramírez, M.; Arnquist, I.; Asner, DM.; Baxter, D.; Behnke, E.; Bhattacharjee, P.... (2017). Dark Matter Search Results from the PICO-60C(3)F(8) Bubble Chamber. Physical Review Letters. 118(25). https://doi.org/10.1103/PhysRevLett.118.251301S11825Olive, K. A. (2014). Review of Particle Physics. Chinese Physics C, 38(9), 090001. doi:10.1088/1674-1137/38/9/090001Komatsu, E., Dunkley, J., Nolta, M. R., Bennett, C. L., Gold, B., Hinshaw, G., … Wright, E. L. (2009). FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: COSMOLOGICAL INTERPRETATION. The Astrophysical Journal Supplement Series, 180(2), 330-376. doi:10.1088/0067-0049/180/2/330Jungman, G., Kamionkowski, M., & Griest, K. (1996). Supersymmetric dark matter. Physics Reports, 267(5-6), 195-373. doi:10.1016/0370-1573(95)00058-5Goodman, M. W., & Witten, E. (1985). Detectability of certain dark-matter candidates. Physical Review D, 31(12), 3059-3063. doi:10.1103/physrevd.31.3059Bertone, G., Hooper, D., & Silk, J. (2005). Particle dark matter: evidence, candidates and constraints. Physics Reports, 405(5-6), 279-390. doi:10.1016/j.physrep.2004.08.031Feng, J. L. (2010). Dark Matter Candidates from Particle Physics and Methods of Detection. Annual Review of Astronomy and Astrophysics, 48(1), 495-545. doi:10.1146/annurev-astro-082708-101659Aubin, F., Auger, M., Genest, M.-H., Giroux, G., Gornea, R., Faust, R., … Storey, C. (2008). Discrimination of nuclear recoils from alpha particles with superheated liquids. New Journal of Physics, 10(10), 103017. doi:10.1088/1367-2630/10/10/103017Amole, C., Ardid, M., Asner, D. M., Baxter, D., Behnke, E., Bhattacharjee, P., … Broemmelsiek, D. (2015). Dark Matter Search Results from the PICO-2LC3F8Bubble Chamber. Physical Review Letters, 114(23). doi:10.1103/physrevlett.114.231302Amole, C., Ardid, M., Arnquist, I. J., Asner, D. M., Baxter, D., Behnke, E., … Brice, S. J. (2016). Improved dark matter search results from PICO-2L Run 2. Physical Review D, 93(6). doi:10.1103/physrevd.93.061101Amole, C., Ardid, M., Asner, D. M., Baxter, D., Behnke, E., Bhattacharjee, P., … Broemmelsiek, D. (2016). Dark matter search results from the PICO-60CF3Ibubble chamber. Physical Review D, 93(5). doi:10.1103/physrevd.93.052014Behnke, E., Behnke, J., Brice, S. J., Broemmelsiek, D., Collar, J. I., … Conner, A. (2012). First dark matter search results from a 4-kgCF3Ibubble chamber operated in a deep underground site. Physical Review D, 86(5). doi:10.1103/physrevd.86.052001Behnke, E., Behnke, J., Brice, S. J., Broemmelsiek, D., Collar, J. I., … Cooper, P. S. (2011). Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two LiterCF3IBubble Chamber. Physical Review Letters, 106(2). doi:10.1103/physrevlett.106.021303Archambault, S., Behnke, E., Bhattacharjee, P., Bhattacharya, S., Dai, X., Das, M., … Zacek, V. (2012). Constraints on low-mass WIMP interactions on 19F from PICASSO. Physics Letters B, 711(2), 153-161. doi:10.1016/j.physletb.2012.03.078Behnke, E., Besnier, M., Bhattacharjee, P., Dai, X., Das, M., Davour, A., … Zacek, V. (2017). Final results of the PICASSO dark matter search experiment. Astroparticle Physics, 90, 85-92. doi:10.1016/j.astropartphys.2017.02.005Felizardo, M., Girard, T. A., Morlat, T., Fernandes, A. C., Ramos, A. R., Marques, J. G., … Marques, R. (2014). The SIMPLE Phase II dark matter search. Physical Review D, 89(7). doi:10.1103/physrevd.89.072013Agostinelli, S., Allison, J., Amako, K., Apostolakis, J., Araujo, H., Arce, P., … Barrand, G. (2003). Geant4—a simulation toolkit. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 506(3), 250-303. doi:10.1016/s0168-9002(03)01368-8Allison, J., Amako, K., Apostolakis, J., Araujo, H., Arce Dubois, P., Asai, M., … Chytracek, R. (2006). Geant4 developments and applications. IEEE Transactions on Nuclear Science, 53(1), 270-278. doi:10.1109/tns.2006.869826Lewin, J. D., & Smith, P. F. (1996). Review of mathematics, numerical factors, and corrections for dark matter experiments based on elastic nuclear recoil. Astroparticle Physics, 6(1), 87-112. doi:10.1016/s0927-6505(96)00047-3Fitzpatrick, A. L., Haxton, W., Katz, E., Lubbers, N., & Xu, Y. (2013). The effective field theory of dark matter direct detection. Journal of Cosmology and Astroparticle Physics, 2013(02), 004-004. doi:10.1088/1475-7516/2013/02/004Anand, N., Fitzpatrick, A. L., & Haxton, W. C. (2014). Weakly interacting massive particle-nucleus elastic scattering response. Physical Review C, 89(6). doi:10.1103/physrevc.89.065501Gresham, M. I., & Zurek, K. M. (2014). Effect of nuclear response functions in dark matter direct detection. Physical Review D, 89(12). doi:10.1103/physrevd.89.123521Gluscevic, V., Gresham, M. I., McDermott, S. D., Peter, A. H. G., & Zurek, K. M. (2015). Identifying the theory of dark matter with direct detection. Journal of Cosmology and Astroparticle Physics, 2015(12), 057-057. doi:10.1088/1475-7516/2015/12/057Fu, C., Cui, X., Zhou, X., Chen, X., Chen, Y., … Fang, D. (2017). Spin-Dependent Weakly-Interacting-Massive-Particle–Nucleon Cross Section Limits from First Data of PandaX-II Experiment. Physical Review Letters, 118(7). doi:10.1103/physrevlett.118.071301Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., … Ansseau, I. (2017). Search for annihilating dark matter in the Sun with 3 years of IceCube data. The European Physical Journal C, 77(3). doi:10.1140/epjc/s10052-017-4689-9Tanaka, T., Abe, K., Hayato, Y., Iida, T., Kameda, J., Koshio, Y., … Nakahata, M. (2011). AN INDIRECT SEARCH FOR WEAKLY INTERACTING MASSIVE PARTICLES IN THE SUN USING 3109.6 DAYS OF UPWARD-GOING MUONS IN SUPER-KAMIOKANDE. The Astrophysical Journal, 742(2), 78. doi:10.1088/0004-637x/742/2/78Choi, K., Abe, K., Haga, Y., Hayato, Y., Iyogi, K., Kameda, J., … Nakahata, M. (2015). Search for Neutrinos from Annihilation of Captured Low-Mass Dark Matter Particles in the Sun by Super-Kamiokande. Physical Review Letters, 114(14). doi:10.1103/physrevlett.114.141301Roszkowski, L., Austri, R. R. de, & Trotta, R. (2007). Implications for the Constrained MSSM from a new prediction forb→sγ. Journal of High Energy Physics, 2007(07), 075-075. doi:10.1088/1126-6708/2007/07/075Akerib, D. S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., Beltrame, P., … Boulton, E. M. (2016). Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment. Physical Review Letters, 116(16). doi:10.1103/physrevlett.116.161302Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Amaro, F. D., Anthony, M., … Bauermeister, B. (2016). XENON100 dark matter results from a combination of 477 live days. Physical Review D, 94(12). doi:10.1103/physrevd.94.122001Adrián-Martínez, S., Albert, A., André, M., Anton, G., Ardid, M., Aubert, J.-J., … Basa, S. (2016). Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope. Physics Letters B, 759, 69-74. doi:10.1016/j.physletb.2016.05.019Adrián-Martínez, S., Albert, A., André, M., Anton, G., Ardid, M., Aubert, J.-J., … Basa, S. (2016). A search for Secluded Dark Matter in the Sun with the ANTARES neutrino telescope. Journal of Cosmology and Astroparticle Physics, 2016(05), 016-016. doi:10.1088/1475-7516/2016/05/016Akerib, D. S., Alsum, S., Araújo, H. M., Bai, X., Bailey, A. J., Balajthy, J., … Biesiadzinski, T. P. (2017). Results from a Search for Dark Matter in the Complete LUX Exposure. Physical Review Letters, 118(2). doi:10.1103/physrevlett.118.021303Tan, A., Xiao, M., Cui, X., Chen, X., Chen, Y., Fang, D., … Gong, H. (2016). Dark Matter Results from First 98.7 Days of Data from the PandaX-II Experiment. Physical Review Letters, 117(12). doi:10.1103/physrevlett.117.121303Angloher, G., Bento, A., Bucci, C., Canonica, L., Defay, X., Erb, A., … Zöller, A. (2016). Results on light dark matter particles with a low-threshold CRESST-II detector. The European Physical Journal C, 76(1). doi:10.1140/epjc/s10052-016-3877-3Agnese, R., Anderson, A. J., Aramaki, T., Asai, M., Baker, W., Balakishiyeva, D., … Billard, J. (2016). New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment. Physical Review Letters, 116(7). doi:10.1103/physrevlett.116.071301Agnes, P., Agostino, L., Albuquerque, I. F. M., Alexander, T., Alton, A. K., Arisaka, K., … Bonfini, G. (2016). Results from the first use of low radioactivity argon in a dark matter search. Physical Review D, 93(8). doi:10.1103/physrevd.93.081101Agnese, R., Anderson, A. J., Asai, M., Balakishiyeva, D., Basu Thakur, R., Bauer, D. A., … Bowles, M. A. (2014). Search for Low-Mass Weakly Interacting Massive Particles with SuperCDMS. Physical Review Letters, 112(24). doi:10.1103/physrevlett.112.241302Agnese, R., Anderson, A. J., Asai, M., Balakishiyeva, D., Barker, D., Basu Thakur, R., … Bowles, M. A. (2015). Improved WIMP-search reach of the CDMS II germanium data. Physical Review D, 92(7). doi:10.1103/physrevd.92.072003Hehn, L., Armengaud, E., Arnaud, Q., Augier, C., Benoît, A., Bergé, L., … Yakushev, E. (2016). Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach. The European Physical Journal C, 76(10). doi:10.1140/epjc/s10052-016-4388-yTovey, D. R., Gaitskell, R. J., Gondolo, P., Ramachers, Y., & Roszkowski, L. (2000). A new model-independent method for extracting spin-dependent cross section limits from dark matter searches. Physics Letters B, 488(1), 17-26. doi:10.1016/s0370-2693(00)00846-7Buchmueller, O., Dolan, M. J., Malik, S. A., & McCabe, C. (2015). Characterising dark matter searches at colliders and direct detection experiments: vector mediators. Journal of High Energy Physics, 2015(1). doi:10.1007/jhep01(2015)037Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., … Abramowicz, H. (2016). Search for new phenomena in final states with an energetic jet and large missing transverse momentum inppcollisions ats=13  TeVusing the ATLAS detector. Physical Review D, 94(3). doi:10.1103/physrevd.94.03200