The CONNIE Experiment (Coherent Neutrino Nucleus Interaction Experiment) is currently collecting reactor neutrino data to search for the undiscovered standard model process of coherent ...neutrino-nucleus scattering (CNNS). The detector is composed of a silicon target of thick, fully-depleted, low-noise CCD detectors. Results from data collected in 2015 indicate backgrounds are controlled, and allow an estimate of sensitivity to be presented for a larger scale detector. A 2016 upgrade, adding additional target mass, and reducing readout noise, has been performed, increasing the total yield of signal events by a factor of 30, and already yielding science-quality data. Low-energy nuclear calibrations have been performed, enabling calibration down to the device energy threshold. An estimate of the sensitivity expected for measuring the coherent neutrino process is presented. Future prospects with improved detector energy thresholds are estimated.
The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charge-coupled devices (CCDs) with the goal of measuring low-energy recoils from coherent elastic ...scattering (CEνNS) of reactor antineutrinos with silicon nuclei and testing nonstandard neutrino interactions (NSI). We report here the first results of the detector array deployed in 2016, considering an active mass 47.6 g (eight CCDs), which is operating at a distance of 30 m from the core of the Angra 2 nuclear reactor, with a thermal power of 3.8 GW. A search for neutrino events is performed by comparing data collected with the reactor on (2.1 kg-day) and reactor off (1.6 kg-day). The results show no excess in the reactor-on data, reaching the world record sensitivity down to recoil energies of about 1 keV (0.1 keV electron equivalent). A 95% confidence level limit for new physics is established at an event rate of 40 times the one expected from the standard model at this energy scale. The results presented here provide a new window to low-energy neutrino physics, allowing one to explore for the first time the energies accessible through the low threshold of CCDs. They will lead to new constraints on NSI from the CEνNS of antineutrinos from nuclear reactors.
DAMIC (Dark Matter in CCDs) is an experiment searching for dark matter particles employing fully-depleted charge-coupled devices. Using the bulk silicon which composes the detector as target, we ...expect to observe coherent WIMP-nucleus elastic scattering. Although located in the SNOLAB laboratory, 2 km below the surface, the CCDs are not completely free of radioactive contamination, in particular coming from radon daughters or from the detector itself. We present novel techniques for the measurement of the radioactive contamination in the bulk silicon and on the surface of DAMIC CCDs. Limits on the Uranium and Thorium contamination as well as on the cosmogenic isotope 32 Si, intrinsically present on the detector, were performed. We have obtained upper limits on the 238 TJ (232 Th) decay rate of 5 (15) kg_1 d_1 at 95% CL. Pairs of spatially correlated electron tracks expected from 32 Si-32 P and 210 Pb-210 Bi beta decays were also measured. We have found a decay rate of 80+l10 -65 kg_1 d_1 for 32 Si and an upper limit of - 35 kg-1 d-1 for 210 Pb, both at 95% CL.
Previous reports evaluating appendicitis in patients with human immunodeficiency virus/ acquired immunodeficiency syndrome have detailed unusual pathology, atypical clinical presentations, and poor ...outcomes. These reports have described small groups of patients and are inconsistent with larger surveys.
A retrospective design was used to evaluate patients diagnosed with human immunodeficiency virus or acquired immunodeficiency syndrome undergoing appendectomy from 1986 to 1995.
Fifty-five patients were evaluated (mean age 33.4 +/- 8.2 years, 98 percent male, 90 percent clinical acquired immunodeficiency syndrome, CD4 count 144.45 +/- 34 cells/mL3). Presenting symptoms included right lower quadrant pain (91 percent), nausea and vomiting (41 percent), diarrhea (22 percent), and generalized abdominal pain (24 percent). Significant findings on examination included right lower quadrant tenderness (91 percent), rebound (74 percent), fever (54 percent), abdominal distention (7 percent), and generalized abdominal tenderness (9.3 percent). Computed tomography was performed in 26 percent and findings were suggestive of appendicitis in 93 percent of cases. Operative findings included acute inflammation (83.3 percent), appendiceal rupture (24 percent), gangrene (29 percent), and normal-appearing appendices (5.5 percent). Unusual findings included Mycobacterium tuberculosis (1.8 percent), atypical mycobacterium (1.8 percent), and chronic appendicitis (3.7 percent). Thirty-day survival was 100 percent. Significant postoperative fevers were noted in 33 percent and lasted 4.63 +/- 1.2 days. The presence of prolonged postoperative fever was linked to lower CD4 counts (p = .05). Follow-up (mean time to follow-up, 1,656 +/- 970 days) was complete in 43 percent. Survival at follow-up was noted in 57.1 percent (mean length of survival after surgery, 837 +/- 155 days).
Appendectomy in patients with human immunodeficiency virus/acquired immunodeficiency syndrome is associated with little morbidity or mortality. Atypical pathology is rarely identified. A higher than expected rate of rupture may be linked to delays before hospitalization or to impaired immune status.
A retrospective study was conducted to determine the influence of the acquired immunodeficiency syndrome (AIDS) epidemic on the incidence, clinical presentation, and outcome of primary ...gastrointestinal lymphoma (stages I and II) over a 20-year period at a single institution. Between 1971 and 1981, there were seven cases. Fifty-eight patients were diagnosed between 1983 and 1993, and 81 per cent were AIDS-related. The mean age overall was 50 years; 81 per cent were male, and 35 per cent presented with acute complications. All tumors were high or intermediate grade B cell lymphomas, and 48 per cent had bulky or advanced disease at presentation. The overall actuarial 5-year survival was 9 per cent. Human immunodeficiency virus status and stage were significant independent prognostic factors. The AIDS-related subgroup had a mean age of 43 years, and 91 per cent were male. Tumor resection was performed in 38 per cent, and the 5-year survival was 2 per cent. The mean age for the non-AIDS-related subgroup was 71 years, and 55 per cent were male. Resection was performed in 39 per cent, and 5-year survival was 28 per cent. AIDS-related disease accounted for the dramatic increase in incidence of primary gastrointestinal lymphoma since 1983. The prognosis for these patients is poor and is dominated by the underlying immunocompromise.
We present a model of the ionization efficiency, or quenching factor, for low-energy nuclear recoils, based on a solution to Lindhard integral equation with binding energy and apply it to the ...calculation of the relative scintillation efficiency and charge yield for nuclear recoils in noble liquid detectors. The quenching model incorporates a constant average binding energy together with an electronic stopping power proportional to the ion velocity, and is an essential input in an analysis of charge recombination processes to predict the ionization and scintillation yields. Our results are comparable to NEST simulations of LXe and LAr and are in good agreement with available data. These studies are relevant to current and future experiments using noble liquids as targets for neutrino physics and the direct searches for dark matter.
Hepatobiliary disease is a common manifestation of acquired immunodeficiency syndrome, although the role of surgical intervention in the spectrum of therapy is unclear.
A retrospective review was ...designed to evaluate the characteristics of patients given a diagnosis of human immunodeficiency virus infection or acquired immunodeficiency syndrome and undergoing cholecystectomy between January 1, 1986, and November 1, 1995.
The study included 40 patients (35 men, 5 women; mean age, 42 +/- 9 years), 33 (82.5 percent) with acquired immunodeficiency syndrome; their mean preoperative T-helper (CD4) cell count was 163/mL3. Gross pathologic findings included acute (n = 9, 22.5 percent) and chronic (n = 31, 77.5 percent) cholecystitis. Gallbladder specimens were positive for cholelithiasis in 28 (70 percent), Cryptococcus organisms in 5 (12.5 percent), cytomegalovirus in 3 (7.5 percent), and lymphoma in 2 (5 percent). The median follow-up time was 48 months (range, 6 to 63 months). The percentage survival was 92.5 percent (n = 37) at 30 days, and 57.5 percent (n = 23), 37.5 percent (n = 15), and 25 percent (n = 10) at 12, 24, and 36 months, respectively. The mean survival time was 25.1 months. The likelihood of survival was directly linked to the CD4 cell count. The mean survival period was 25 months for patients with CD4 cell counts less than 200/mL3 compared with 48 months for those with CD4 cell counts greater than 200/mL3.
Although the pathologic changes identified in patients with acquired immunodeficiency syndrome may occasionally be atypical, the clinical presentation, indications for operation, and pathologic findings identified are quite common. Patients tolerate cholecystectomy well with good long-term outcome and minimal infectious complications. Even in patients with the most compromised immune status, a 2-year survival after operation is acceptable. Cholecystectomy has a clear role in the spectrum of treatment for biliary disease relative to acquired immunodeficiency syndrome.
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