Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 221
Filtrar
1.
J Frailty Aging ; 9(3): 134-138, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32588026

RESUMEN

BACKGROUND: High levels of intramuscular adipose tissue and low levels of capillarization are both predicative of low muscle and mobility function in older adults, however little is known about their relationship. OBJECTIVES: The purpose of this study was to examine the relationship of intramuscular adipose tissue and capillarization in older adults. SETTING: An outpatient medical center. PARTICIPANTS: Forty-seven sedentary adults (age 59.9 ± 1.0 years, BMI 32.0 ± 0.7 kg/m2, VO2max 22.4 ± 0.7 ml/kg/min); Measurements: All participants underwent CT scans to determine intramuscular adipose tissue and muscle biopsies to determine capillarization in the mid-thigh. A step-wise hierarchical linear regression analysis was used to examine the contributions of age, sex, race, body mass index, 2-hour postprandial glucose, VO2max, and muscle capillarization, to the variability in intramuscular adipose tissue. RESULTS: The predictors as a group accounted for 38.1% of the variance in intramuscular adipose tissue, with body mass index and capillarization each significantly contributing to the final model (P<0.001). The part correlation of body mass index with intramuscular adipose tissue was r = 0.47, and the part correlation of capillarization with intramuscular adipose tissue was r = 0.39, indicating that body mass index and capillarization explained 22.1%, and 15.2% of the variance in intramuscular adipose tissue. CONCLUSIONS: While increased muscle capillarization is typically thought of as a positive development, in some clinical conditions, such as tendinopathies, an increase in capillarization is part of the pathological process related to expansion of the extracellular matrix and fibrosis. This may also be an explanation for the surprising finding that high capillarization is related to high levels of intramuscular adipose tissue. Future studies are necessary to determine the relationship of changes in both capillarization and intramuscular adipose tissue after interventions, such as exercise.


Asunto(s)
Tejido Adiposo/metabolismo , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/metabolismo , Índice de Masa Corporal , Capilares/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Muslo/irrigación sanguínea
2.
AIDS Behav ; 24(3): 839-846, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30945030

RESUMEN

To assess the potential for decreased condom use as pre-exposure prophylaxis (PrEP) is scaled-up in Latin America, we examined HIV prevention method preferences (neither PrEP nor condoms, condoms only, PrEP only, or PrEP with condoms) within 1302 sexual partnerships reported by 397 HIV-negative men who have sex with men (MSM) and transgender women (TW) in Tijuana, Mexico. Using PrEP with condoms (56%) was preferred to using condoms only (24%), using PrEP only (17%), and using neither PrEP nor condoms (3%). Compared to using condoms only, using PrEP only was preferred within primary (adjusted odds ratio [AOR] = 4.13, 95% confidence interval [CI] 1.92, 8.90) and condomless sex practicing (AOR = 6.97, 95% CI 3.92, 12.40) partnerships, suggesting PrEP use may not displace condom use among MSM and TW in Tijuana and other similar settings.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Infecciones por VIH/prevención & control , Homosexualidad Masculina/psicología , Prioridad del Paciente , Profilaxis Pre-Exposición/métodos , Personas Transgénero/psicología , Adulto , Fármacos Anti-VIH/uso terapéutico , Condones , Femenino , Infecciones por VIH/epidemiología , Homosexualidad Masculina/estadística & datos numéricos , Humanos , Masculino , México , Persona de Mediana Edad , Sexo Seguro , Conducta Sexual , Parejas Sexuales , Personas Transgénero/estadística & datos numéricos
3.
Am J Transplant ; 18(3): 696-703, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29087035

RESUMEN

Preliminary evidence suggests that postoperative cognitive dysfunction (POCD) is common after lung transplantation. The impact of POCD on clinical outcomes has yet to be studied. The association between POCD and longer-term survival was therefore examined in a pilot study of posttransplantation survivors. Forty-nine participants from a prior randomized clinical trial underwent a neurocognitive assessment battery pretransplantation and 6 months posttransplantation, including assessments of the domains of Executive Function (Trail Making Test, Stroop, Digit Span), Processing Speed (Ruff 2 and 7 Test, Digit Symbol Substitution Test), and Verbal Memory (Verbal Paired Associates, Logical Memory, Animal Naming, and Controlled Oral Word Association Test). During a 13-year follow-up, 33 (67%) participants died. Greater neurocognition was associated with longer survival (hazard ratio [HR] = 0.49 [0.25-0.96], P = .039), and this association was strongest on tests assessing Processing Speed (HR = 0.58 [0.36-0.95], P = .03) and Executive Function (HR = 0.52 [0.28-0.97], P = .040). In addition, unadjusted analyses suggested an association between greater Memory performance and lower risk of CLAD (HR = 0.54 [0.29-1.00], P = .050). Declines in Executive Function tended to be predictive of worse survival. These preliminary findings suggest that postoperative neurocognition is predictive of subsequent mortality among lung transplant recipients. Further research is needed to confirm these findings in a larger sample and to examine mechanisms responsible for this relationship.


Asunto(s)
Trastornos del Conocimiento/mortalidad , Rechazo de Injerto/mortalidad , Trasplante de Pulmón/efectos adversos , Complicaciones Posoperatorias , Calidad de Vida , Trastornos del Conocimiento/etiología , Femenino , Estudios de Seguimiento , Rechazo de Injerto/etiología , Supervivencia de Injerto , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Proyectos Piloto , Pronóstico , Factores de Riesgo , Tasa de Supervivencia
4.
Conserv Biol ; 32(2): 390-400, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-28815792

RESUMEN

Unsustainable wildlife trade affects biodiversity and the livelihoods of communities dependent upon those resources. Wildlife farming has been proposed to promote sustainable trade, but characterizing markets and understanding consumer behavior remain neglected but essential steps in the design and evaluation of such operations. We used sea turtle trade in the Cayman Islands, where turtles have been farm raised for human consumption for almost 50 years, as a case study to explore consumer preferences toward wild-sourced (illegal) and farmed (legal) products and potential conservation implications. Combining methods innovatively (including indirect questioning and choice experiments), we conducted a nationwide trade assessment through in-person interviews from September to December 2014. Households were randomly selected using disproportionate stratified sampling, and responses were weighted based on district population size. We approached 597 individuals, of which 37 (6.2%) refused to participate. Although 30% of households had consumed turtle in the previous 12 months, the purchase and consumption of wild products was rare (e.g., 64-742 resident households consumed wild turtle meat [i.e., 0.3-3.5% of households] but represented a large threat to wild turtles in the area due to their reduced populations). Differences among groups of consumers were marked, as identified through choice experiments, and price and source of product played important roles in their decisions. Despite the long-term practice of farming turtles, 13.5% of consumers showed a strong preference for wild products, which demonstrates the limitations of wildlife farming as a single tool for sustainable wildlife trade. By using a combination of indirect questioning, choice experiments, and sales data to investigate demand for wildlife products, we obtained insights about consumer behavior that can be used to develop conservation-demand-focused initiatives. Lack of data from long-term social-ecological assessments hinders the evaluation of and learning from wildlife farming. This information is key to understanding under which conditions different interventions (e.g., bans, wildlife farming, social marketing) are likely to succeed.


Asunto(s)
Conservación de los Recursos Naturales , Comportamiento del Consumidor , Agricultura , Animales , Animales Salvajes , Comercio , Granjas , Humanos
5.
Osteoarthritis Cartilage ; 24(9): 1528-34, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27090577

RESUMEN

OBJECTIVE: To investigate the effects of pain coping skills training (PCST) and a lifestyle behavioral weight management (BWM) program on inflammatory markers and biomarker associations with pain and function in the OA LIFE study. METHOD: Serum samples were available from a subset (N = 169) of the overweight or obese knee OA participants in the OA LIFE study that evaluated: PCST, BWM, combined PCST + BWM, or standard care (SC). Inflammatory markers (hsCRP, IL-1ra, IL-1ß, IL-6, IL-8, TNF-α, TNFRI, TNFRII, and hyaluronic acid (HA)), and adipokines (leptin and adiponectin) were measured before and after the 24-week treatment period. Biomarkers were assessed for effects of treatment and for associations with change in weight, pain and disability (unadjusted and adjusted for age, race, sex, baseline body mass index (BMI), and baseline biomarker concentration). RESULTS: PCST + BWM was associated with significant reductions in hsCRP (P = 0.0014), IL-6 (P = 0.0075), and leptin (P = 0.0001). After adjustment, there was a significant effect of PCST + BWM on changes in leptin (b = -0.19, P = 0.01) and IL-6 (b = -0.25, P = 0.02) relative to SC. Reductions in leptin and IL-6 were significantly correlated with reductions in weight, BMI and Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain; reductions in IL-6 were correlated with improvements in WOMAC and Arthritis Impact Measurement Scales (AIMS) physical function. By mediation analyses, weight loss was responsible for 54% of the change in IL-6 and all of the change in leptin. CONCLUSIONS: OA-related inflammatory markers were reduced by a 24-week combined PCST + BWM intervention. This suggests that the inflammatory state can be successfully modified in the context of a readily instituted clinical intervention with a positive clinical outcome.


Asunto(s)
Osteoartritis de la Rodilla , Adipocitos , Biomarcadores , Cognición , Humanos , Inflamación , Ontario
7.
J Prev Alzheimers Dis ; 3(1): 53-64, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26900574

RESUMEN

Cognitive decline is an increasingly important public health problem, with more than 100 million adults worldwide projected to develop dementia by 2050. Accordingly, there has been an increased interest in preventive strategies that diminish this risk. It has been recognized that lifestyle factors including dietary patterns, may be important in the prevention of cognitive decline and dementia in later life. Several dietary components have been examined, including antioxidants, fatty acids, and B vitamins. In addition, whole dietary eating plans, including the Mediterranean diet (MeDi), and the Dietary Approaches to Stop Hypertension (DASH) diet, with and without weight loss, have become areas of increasing interest. Although prospective epidemiological studies have observed that antioxidants, fatty acids, and B vitamins are associated with better cognitive functioning, randomized clinical trials have generally failed to confirm the value of any specific dietary component in improving neurocognition. Several randomized trials have examined the impact of changing 'whole' diets on cognitive outcomes. The MeDi and DASH diets offer promising preliminary results, but data are limited and more research in this area is needed.

8.
Am J Transplant ; 16(1): 271-7, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26366639

RESUMEN

Lung transplantation has become an increasingly common treatment for patients with end-stage lung disease. Few studies have examined psychosocial risk factors for mortality in transplant recipients, despite evidence suggesting that elevated levels of negative affect are associated with greater mortality following major cardiac surgery. We therefore examined the relationship between negative affect early after lung transplantation and long-term survival in a sample of 132 lung transplant recipients (28 cystic fibrosis, 64 chronic obstructive pulmonary disease, 26 idiopathic pulmonary fibrosis, 14 other) followed for up to 13.5 years (median 7.4 years) following transplantation. Patients underwent both medical and psychosocial assessments 6 months following transplantation, which included the Beck Depression Inventory-II (BDI-II), Spielberger Anxiety Inventory, and General Health Questionnaire (GHQ). Over the course of follow-up, 80 (61%) participants died. Controlling for demographic factors, native lung disease, disease severity, family income, education level, social support, and frequency of posttransplant rejection, elevated symptoms of depression (BDI-II: HR = 1.31, p = 0.011) and distress (GHQ: HR = 1.28, p = 0.003) were associated with increased mortality. Higher levels of depression and general distress, but not anxiety, measured 6 months following lung transplantation are associated with increased mortality, independent of background characteristics and medical predictors.


Asunto(s)
Ansiedad/mortalidad , Trastorno Depresivo Mayor/mortalidad , Trasplante de Pulmón/psicología , Complicaciones Posoperatorias , Receptores de Trasplantes/psicología , Ansiedad/diagnóstico , Ansiedad/psicología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/psicología , Femenino , Estudios de Seguimiento , Rechazo de Injerto , Supervivencia de Injerto , Humanos , Trasplante de Pulmón/efectos adversos , Trasplante de Pulmón/mortalidad , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo
9.
Phys Rev Lett ; 115(8): 081102, 2015 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-26340177

RESUMEN

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19) GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100 TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

10.
Phys Rev Lett ; 114(17): 171102, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25978221

RESUMEN

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fµ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

11.
Eur Phys J C Part Fields ; 75(3): 116, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25995705

RESUMEN

We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.

12.
Occup Med (Lond) ; 65(2): 110-6, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25589707

RESUMEN

BACKGROUND: In the evolving work environment of global competition, the associations between work and home stress and psychological well-being are not well understood. AIMS: To examine the impact of psychosocial stress at work and at home on anxiety and depression. METHODS: In medically healthy employed men and women (aged 30-60), serial regression analyses were used to determine the independent association of psychosocial stress at work and at home with depression symptoms, measured using the Beck Depression Inventory-II (BDI-II), and anxiety symptoms, measured using the Spielberger Trait Anxiety Inventory (STAI). Psychosocial stress at work was measured using the Job Content Questionnaire to assess job psychological demands, job control, job social support and job insecurity. Psychosocial stress at home was assessed by 12 questions including stress at home, personal problems, family demands and feelings about home life. RESULTS: Serial regression analyses in 129 subjects revealed that job insecurity and home stress were most strongly associated with depression and anxiety symptoms. Job insecurity accounted for 9% of the variation both in BDI-II scores and in STAI scores. Home stress accounted for 13 and 17% of the variation in BDI-II scores and STAI scores, respectively. In addition, job social support was significantly and independently associated with STAI scores but not BDI-II scores. CONCLUSIONS: Work and home stress were associated with anxiety and depression symptoms in both men and women. Both work and home stress should be considered in studies evaluating anxiety and depression in working populations.


Asunto(s)
Ansiedad/etiología , Depresión/etiología , Enfermedades Profesionales/diagnóstico , Salud Laboral , Estrés Psicológico/diagnóstico , Lugar de Trabajo/psicología , Adulto , Ansiedad/diagnóstico , Ansiedad/epidemiología , Depresión/diagnóstico , Depresión/epidemiología , Empleo , Femenino , Humanos , Satisfacción en el Trabajo , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/epidemiología , Medio Social , Apoyo Social , Estrés Psicológico/epidemiología , Encuestas y Cuestionarios
13.
J Crit Care ; 30(1): 126-9, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25307975

RESUMEN

BACKGROUND: Delirium is relatively common after lung transplantation, although its prevalence and prognostic significance have not been systematically studied. The purpose of the present study was to examine pretransplant predictors of delirium and the short-term impact of delirium on clinical outcomes among lung transplant recipients. METHODS: Participants underwent pretransplant cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status and the Trail Making Test. After transplant, delirium was assessed using the Confusion Assessment Method until discharge. RESULTS: Sixty-three patients were transplanted between March and November 2013, of which 23 (37%) developed delirium. Among transplanted patients, 48 patients completed pretransplant cognitive testing. Better pretransplant cognitive function was associated with lower risk of delirium (odds ratio, 0.69 [95% confidence interval 0.48, 0.99], P = .043); and demographic and clinical features including native disease (P = .236), the Charlson comorbidity index (P = .581), and the lung allocation score (P = .871) were unrelated to risk of delirium, although there was a trend for women to experience delirium less frequently (P = .071). The presence (P = .006) and duration (P = .027) of delirium were both associated with longer hospital stays. CONCLUSION: Delirium occurs in more than one-third of patients after lung transplantation. Delirium was associated with poorer pretransplant cognitive functioning and longer hospital stays, after accounting for other medical and demographic factors.


Asunto(s)
Cognición , Delirio/etiología , Tiempo de Internación , Trasplante de Pulmón/efectos adversos , Adulto , Anciano , Confusión/diagnóstico , Delirio/diagnóstico , Delirio/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Oportunidad Relativa , Prevalencia , Pronóstico , Estudios Prospectivos , Prueba de Secuencia Alfanumérica
14.
Genes Brain Behav ; 13(8): 841-9, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25287572

RESUMEN

Trisomy X, the presence of an extra X chromosome in females (47,XXX), is a relatively common but under-recognized chromosomal disorder associated with characteristic cognitive and behavioral features of varying severity. The objective of this study was to determine whether there were neuroanatomical differences in girls with Trisomy X that could relate to cognitive and behavioral differences characteristic of the disorder during childhood and adolescence. MRI scans were obtained on 35 girls with Trisomy X (mean age 11.4, SD 5.5) and 70 age- and sex-matched healthy controls. Cognitive and behavioral testing was also performed. Trisomy X girls underwent a semi-structured psychiatric interview. Regional brain volumes and cortical thickness were compared between the two groups. Total brain volume was significantly decreased in subjects with Trisomy X, as were all regional volumes with the exception of parietal gray matter. Differences in cortical thickness had a mixed pattern. The subjects with Trisomy X had thicker cortex in bilateral medial prefrontal cortex and right medial temporal lobe, but decreased cortical thickness in both lateral temporal lobes. The most common psychiatric disorders present in this sample of Trisomy X girls included anxiety disorders (40%), attention-deficit disorder (17%) and depressive disorders (11%). The most strongly affected brain regions are consistent with phenotypic characteristics such as language delay, poor executive function and heightened anxiety previously described in population-based studies of Trisomy X and also found in our sample.


Asunto(s)
Trastornos de Ansiedad/patología , Trastorno por Déficit de Atención con Hiperactividad/patología , Encéfalo/patología , Trastorno Depresivo/patología , Trastornos de los Cromosomas Sexuales del Desarrollo Sexual/patología , Trisomía/patología , Adolescente , Trastornos de Ansiedad/complicaciones , Trastornos de Ansiedad/psicología , Trastorno por Déficit de Atención con Hiperactividad/complicaciones , Trastorno por Déficit de Atención con Hiperactividad/psicología , Estudios de Casos y Controles , Niño , Preescolar , Cromosomas Humanos X , Trastorno Depresivo/complicaciones , Trastorno Depresivo/psicología , Femenino , Humanos , Imagen por Resonancia Magnética , Aberraciones Cromosómicas Sexuales , Trastornos de los Cromosomas Sexuales del Desarrollo Sexual/complicaciones , Trastornos de los Cromosomas Sexuales del Desarrollo Sexual/psicología , Adulto Joven
15.
Phys Rev Lett ; 113(10): 101101, 2014 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-25238345

RESUMEN

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

16.
Science ; 342(6161): 1242856, 2013 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-24264993

RESUMEN

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4σ level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

17.
Phys Rev Lett ; 111(8): 081801, 2013 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-24010427

RESUMEN

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

18.
Phys Rev Lett ; 111(2): 021103, 2013 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-23889381

RESUMEN

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,µ,τ) (ν(e,µ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

19.
Obesity (Silver Spring) ; 21(7): 1350-6, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23687104

RESUMEN

OBJECTIVE: To determine whether aerobic exercise training + weight loss (AEX + WL) would affect the expression of myostatin and its relationship with insulin sensitivity in a longitudinal, clinical intervention study. DESIGN AND METHODS: Thirty-three obese sedentary postmenopausal women and men (n = 17 and 16, age: 61 ± 1 years, body mass index: 31 ± 1 kg/m(2) , VO2 max: 21.9 ± 1.0 mL/kg/min, X ± Standard error of the mean (SEM)) completed 6 months of 3 days/week AEX + WL. During an 80 mU m(-2) min(-1) hyperinsulinemic-euglycemic clamp, we measured glucose utilization (M), myostatin, myogenin, and MyoD gene expression by real-time RT-PCR in vastus lateralis muscle at baseline and 2 h. RESULTS: Body weight (-8%) and fat mass (-17%) decreased after AEX + WL (P < 0.001). Fat-free mass (FFM) and mid-thigh muscle area by computed tomography did not change but muscle attenuation increased (P < 0.05). VO2 max increased 14% (P < 0.001). AEX + WL increased M by 18% (P < 0.01). Myostatin gene expression decreased 19% after AEX + WL (P < 0.05). Basal mRNA myostatin levels were negatively associated with M before the intervention (r = -0.43, P < 0.05). Insulin infusion increased myoD and myogenin expression before and after AEX + WL (both P < 0.001) but basal levels did not change. The insulin effect on myostatin expression was associated with the change in M after AEX + WL (r = 0.56, P < 0.005). CONCLUSIONS: Exercise and weight loss results in a downregulation of myostatin mRNA and an improvement in insulin sensitivity in obese older men and women.


Asunto(s)
Ejercicio Físico/fisiología , Resistencia a la Insulina/fisiología , Músculo Esquelético/metabolismo , Miostatina/metabolismo , Pérdida de Peso , Anciano , Glucemia/metabolismo , Índice de Masa Corporal , Peso Corporal , Regulación hacia Abajo , Ayuno , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/sangre , Estilo de Vida , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Miostatina/genética , Obesidad/metabolismo , Obesidad/terapia , Posmenopausia , Análisis de Regresión , Conducta Sedentaria , Muslo/fisiología
20.
Phys Rev Lett ; 110(13): 131302, 2013 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-23581307

RESUMEN

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000 GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35 GeV/c2 for most WIMP models.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA