Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) ...experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.
BACKGROUND: Weight management interventions can be extended using mobile telephone technology to deliver support in real‐time, real‐world settings. The present study aimed to determine whether text ...messaging helped patients maintain or lose weight following a weight‐loss programme. METHODS: In this controlled study, overweight and obese body mass index (BMI) >30 kg m–² or >28 kg m–² with co‐morbidities adults who completed a weight‐loss programme participated in an additional 12‐week text message intervention Lifestyle, Eating and Activity Programme (LEAP) Beep. Patients were allocated goals for steps, fruit, vegetable and breakfast consumption. Patients regularly ‘texted’ their progress and received tailored practitioner feedback. Pre/post‐intervention body weight, waist circumference (WC), BMI, quality of life (QOL), anxiety and depression measurements were compared retrospectively with a control group offered weight checks only. RESULTS: Compared to control (n = 17), the intervention group's (n = 17) body weight, WC and BMI reduced significantly (−1.6 versus 0.7 kg, P = 0.006; −2.2 versus 1.5 cm, P = 0.0005; −0.6 versus 0.7 kg m–², P = 0.03, respectively). QOL and depression scores also improved (−6.8 versus 1 point, P = 0.134; −0.2 versus 0.2 points, P = 0.228). No difference was observed in anxiety scores between the groups. Intervention versus control group follow‐up attendance improved significantly (4.4 versus 1.7 attendances, P = 0.0005). CONCLUSIONS: LEAP Beep promoted losses in weight, WC and BMI, and improved QOL parameters and follow‐up attendance. Text messaging is a cheap, portable, convenient and innovative medium facilitating goal setting, self‐monitoring and information exchange. Further improvements to automation at the same time as maintaining individual support are necessary to ease practitioner burden. Text messaging offers cost‐efficient dietetic input, opening up possibilities for practitioner‐to‐patient support and yields positive weight outcomes following initial weight loss.
Background: National obesity guidance stipulates that weight management interventions provide ongoing support (National Institute for Health and Clinical Excellence, 2006). Weight management ...interventions can be extended using mobile telephone technology to deliver support in real‐time, real‐world settings (Heron, 2010). Regular exercise, a low‐fat diet, breakfast consumption, goal setting and self‐monitoring are behaviours of successful weight losers and maintainers (Wing et al., 2001). This study aimed to determine whether a text message‐based intervention helped participants maintain or lose weight after completion of a weight‐loss programme.
Methods: In this controlled study, overweight body mass index (BMI) >30 kg m−2 or >28 kg m−2 with co‐morbidities adults who completed a weight management programme participated in an additional 12‐week text message based intervention ‘LEAP Beep’ (Lifestyle, Eating and Activity Programme). Participants were allocated daily goals for steps, fruit, vegetable and breakfast consumption. Twice a week, participants ‘texted’ their progress and received practitioner feedback. Pre‐ and post‐intervention body mass, waist circumference (WC), BMI, quality of life (QOL), anxiety and depression measurements were compared retrospectively with a control group offered standard care (weight checks only). Paired t‐tests and Wilcoxon signed ranks tests evaluated the significance of differences between pre‐ and post‐intervention variables for normally and non‐normally distributed data, respectively. Statistical significance was measured at P ≤ 0.05 using SPSS, version 17 (SPSS Inc., Chicago, IL, USA). Patients’ satisfaction with the intervention was surveyed. Ethical approval was given by the Leicestershire, Northamptonshire and Rutland Research Ethics Committee.
Results: Compared to a control group n = 17; four males, 13 females; mean (SD) age 59.1 (9.5) years, the intervention group n = 17, seven males; 10 females; mean (SD) age 58.3 (12.1) years body mass, WC and BMI were reduced significantly (Table 1). QOL and depression scores improved, although not significantly. No difference was found between group anxiety scores. Satisfaction surveys showed 100% (n = 15) of participants were satisfied with the programme overall.
1
Health variable differences between intervention and control groups
Variable
Intervention group pre – post‐change
Control group pre – post‐change
Between group difference
Difference between groups (P)
Body mass (kg)
−1.6
+0.7
2.3
0.006
WC (cm)
−2.2
+1.5
3.7
0.0005
BMI (kg m−2)
−0.6
+0.7
1.5
0.03
QOL (points)
−6.8
+1
7.8
0.134
Depression (points)
−0.2
+0.2
0.4
0.228
Anxiety (points)
−0.1
−0.1
0
–
Discussion: This study showed that ‘LEAP Beep’ was highly acceptable to participants and successfully promoted weight, WC and BMI losses, as well as improved QOL parameters. This research is strengthened because it was carried out in a real‐world setting reflecting normal clinical practice. In the future, further improvements to automation at the same time as maintaining individual support are necessary to ease practitioner burden. Text messaging is a cheap, portable, convenient and innovative medium facilitating goal setting, self‐monitoring and information exchange.
Conclusions: Text messaging inclusive of practitioner feedback opens up increasing possibilities for practitioner to patient support and yields positive weight outcomes after initial weight loss.
References: Heron, K.E. & Smyth, J.M. (2010) Ecological momentary interventions: incorporating mobile technology into psychosocial and health behaviour treatments. Br. J. Health. Psychiatry 15, 1–39.
NICE (2006) Obesity: Guidance on the Prevention, Identification, Assessment and Management of Overweight and Obesity in Adults and Children. Clinical Guideline 43. London: NICE.
Wing, R.R. & Hill, J.O. (2001) Successful weight loss maintenance. Annu. Rev. Nutr. 21, 323–341.
SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass particles (with masses ≤10 GeV/c2) that may constitute dark matter by using cryogenic detectors of two types ...(HV and iZIP) and two target materials (germanium and silicon). The experiment is being designed with an initial sensitivity to nuclear recoil cross sections ∼1×10−43 cm2 for a dark matter particle mass of 1 GeV/c2, and with capacity to continue exploration to both smaller masses and better sensitivities. The phonon sensitivity of the HV detectors will be sufficient to detect nuclear recoils from sub-GeV dark matter. A detailed calibration of the detector response to low-energy recoils will be needed to optimize running conditions of the HV detectors and to interpret their data for dark matter searches. Low-activity shielding, and the depth of SNOLAB, will reduce most backgrounds, but cosmogenically produced H3 and naturally occurring Si32 will be present in the detectors at some level. Even if these backgrounds are 10 times higher than expected, the science reach of the HV detectors would be over 3 orders of magnitude beyond current results for a dark matter mass of 1 GeV/c2. The iZIP detectors are relatively insensitive to variations in detector response and backgrounds, and will provide better sensitivity for dark matter particles with masses ≳5 GeV/c2. The mix of detector types (HV and iZIP), and targets (germanium and silicon), planned for the experiment, as well as flexibility in how the detectors are operated, will allow us to maximize the low-mass reach, and understand the backgrounds that the experiment will encounter. Upgrades to the experiment, perhaps with a variety of ultra-low-background cryogenic detectors, will extend dark matter sensitivity down to the “neutrino floor,” where coherent scatters of solar neutrinos become a limiting background.
New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3I and located in the SNOLAB underground laboratory. PICO-60 is the largest ...bubble chamber to search for dark matter to date. With an analyzed exposure of 92.8 livedays, PICO-60 exhibits the same excellent background rejection observed in smaller bubble chambers. Alpha decays in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but not identical to that reported recently in a C3F8 bubble chamber. PICO-60 also observes a large population of unknown background events, exhibiting acoustic, spatial, and timing behaviors inconsistent with those expected from a dark matter signal. These behaviors allow for analysis cuts to remove all background events while retaining 48.2% of the exposure. Stringent limits on weakly interacting massive particles interacting via spin-dependent proton and spin-independent processes are set, and most interpretations of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei are ruled out.
New data are reported from a second run of the 2-liter PICO-2L C sub(3) F sub(8) bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show ...that measures taken to control particulate contamination in the superheated fluid resulted in the absence of the anomalous background events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering to date for WIMP masses <50GeV/c super(2).
Percolation model of excess electrical noise in transition-edge sensors Lindeman, M.A.; Anderson, M.B.; Bandler, S.R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2006, Letnik:
559, Številka:
2
Journal Article
Recenzirano
We present a geometrical model to describe excess electrical noise in transition-edge sensors (TESs). In this model, a network of fluctuating resistors represents the complex dynamics inside a TES. ...The fluctuations can cause several resistors in series to become superconducting. Such events short out part of the TES and generate noise because much of the current percolates through low resistance paths. The model predicts that excess white noise increases with decreasing TES bias resistance (
R/
R
N) and that perpendicular zebra stripes reduce noise and alpha of the TES by reducing percolation.
PDF
