Exotic Dark Matter Search with the Majorana Demonstrator.

With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the Majorana Demonstrator enable searches for several classes of exotic dark matter (DM) models. In this work, we report new experimental limits on keV-scale sterile neutrino DM via the transition magnetic moment from conversion to active neutrinos ν_{s}→ν_{a}. We report new limits on fermionic dark matter absorption (χ+A→ν+A) and sub-GeV DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). These searches utilize the (1-100)-keV low-energy region of a 37.5-kg y exposure collected by the Demonstrator between May 2016 and November 2019 using a set of ^{76}Ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation.

Final Result of the Majorana Demonstrator's Search for Neutrinoless Double-ß Decay in

The Majorana Demonstrator searched for neutrinoless double-ß decay (0νßß) of ^{76}Ge using modular arrays of high-purity Ge detectors operated in vacuum cryostats in a low-background shield. The arrays operated with up to 40.4 kg of detectors (27.2 kg enriched to ∼88% in ^{76}Ge). From these measurements, the Demonstrator has accumulated 64.5 kg yr of enriched active exposure. With a world-leading energy resolution of 2.52 keV FWHM at the 2039 keV Q_{ßß} (0.12%), we set a half-life limit of 0νßß in ^{76}Ge at T_{1/2}>8.3×10^{25} yr (90% C.L.). This provides a range of upper limits on m_{ßß} of (113-269) meV (90% C.L.), depending on the choice of nuclear matrix elements.

Constraints on the Decay of

^{180m}Ta is a rare nuclear isomer whose decay has never been observed. Its remarkably long lifetime surpasses the half-lives of all other known ß and electron capture decays due to the large K-spin differences and small energy differences between the isomeric and lower-energy states. Detecting its decay presents a significant experimental challenge but could shed light on neutrino-induced nucleosynthesis mechanisms, the nature of dark matter, and K-spin violation. For this study, we repurposed the Majorana Demonstrator, an experimental search for the neutrinoless double-beta decay of ^{76}Ge using an array of high-purity germanium detectors, to search for the decay of ^{180m}Ta. More than 17 kg, the largest amount of tantalum metal ever used for such a search, was installed within the ultralow-background detector array. In this Letter, we present results from the first year of Ta data taking and provide an updated limit for the ^{180m}Ta half-life on the different decay channels. With new limits up to 1.5×10^{19} yr, we improved existing limits by 1-2 orders of magnitude which are the most sensitive searches for a single ß and electron capture decay ever achieved. Over all channels, the decay can be excluded for T_{1/2}<0.29×10^{18} yr.

Erratum: Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator [Phys. Rev. Lett. 129, 080401 (2022)].

This corrects the article DOI: 10.1103/PhysRevLett.129.080401.

Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator.

The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in ^{76}Ge) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19-100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, λ, providing a factor of 40-100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Diòsi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit.

Search for Solar Axions via Axion-Photon Coupling with the Majorana Demonstrator.

Axions were originally proposed to explain the strong-CP problem in QCD. Through axion-photon coupling, the Sun could be a major source of axions, which could be measured in solid state detection experiments with enhancements due to coherent Primakoff-Bragg scattering. The Majorana Demonstrator experiment has searched for solar axions with a set of ^{76}Ge-enriched high purity germanium detectors using a 33 kg-yr exposure collected between January, 2017 and November, 2019. A temporal-energy analysis gives a new limit on the axion-photon coupling as g_{aγ}<1.45×10^{-9} GeV^{-1} (95% confidence level) for axions with mass up to 100 eV/c^{2}. This improves laboratory-based limits between about 1 eV/c^{2} and 100 eV/c^{2}.

Immune cell populations residing in mesenteric adipose depots and mesenteric lymph nodes of lean dairy cows.

Inconsistent evidence of inflammatory immune cell infiltrates in adipose tissues with extensive triglyceride mobilization raises the possibility that regulatory or anti-inflammatory immune cell populations reside within the mesenteric adipose tissue (MAT) and mesenteric lymph nodes (MLN). These resident immune cell populations may be involved in attenuating the inflammatory response. We explored the immune cell population of MAT and MLN collected from lean, lactating Holstein cows without apparent disease in an abattoir (n = 42). Lean cows had a body condition score of 2.6 ± 0.1 (mean ± SD) with a greater frequency of adipocyte area occurring in small rather than large adipocytes. Cells were labeled with monoclonal antibodies specific to bovine leukocyte antigens for enumeration by flow cytometry. Within both lymph node and adipose tissues, relatively large subpopulations of cells expressed the ß2 integrins CD11b and CD11c, class II major histocompatibility antigens (MHCII), and the SIIRP-1α receptor (CD172a) typical of dendritic cells and macrophages. Macrophage/dendritic cell heterogeneity was marked by ß2 integrin expression alone or in conjunction with CD172a or MHCII across subpopulations from both tissues; CD209, the DC-SIGN c-type lectin receptor of dendritic cells, was not detected by fluorescence-activated cell sorting in either tissue. Lymphocytes comprised 74.1 ± 3.7% and 13.7 ± 3.7% of the MLN and MAT cell populations, respectively, and CD3+CD4+ lymphocytes accounted for 49.8 ± 9.9% of the MLN and 6.13 ± 1.23% of the MAT cells. Fox P3+ regulatory lymphocytes comprised 15.3 ± 1.1% and 6.73 ± 0.52% of the MLN and MAT cells, whereas γδ+ lymphocytes accounted for 6.65 ± 0.74% and 3.91 ± 0.43% of the MLN and MAT cells, respectively. Subpopulations of CD3+CD8+ cytotoxic T cells and CD3+CD11c+ innate lymphocytes were present in MLN but not MAT. These results show that subpopulations of resident tissue macrophages, dendritic cells, T helper lymphocytes, regulatory T lymphocytes (Tregs), and γδ lymphocytes reside in mesenteric lymph nodes and adipose tissues. Balance in the innate and adaptive immune functions embedded in these tissues could support metabolic health.

Exposure to household air pollution from biomass-burning cookstoves and HbA1c and diabetic status among Honduran women.

Household air pollution from biomass cookstoves is estimated to be responsible for more than two and a half million premature deaths annually, primarily in low and middle-income countries where cardiometabolic disorders, such as Type II Diabetes, are increasing. Growing evidence supports a link between ambient air pollution and diabetes, but evidence for household air pollution is limited. This cross-sectional study of 142 women (72 with traditional stoves and 70 with cleaner-burning Justa stoves) in rural Honduras evaluated the association of exposure to household air pollution (stove type, 24-hour average kitchen and personal fine particulate matter [PM2.5 ] mass and black carbon) with glycated hemoglobin (HbA1c) levels and diabetic status based on HbA1c levels. The prevalence ratio (PR) per interquartile range increase in pollution concentration indicated higher prevalence of prediabetes/diabetes (vs normal HbA1c) for all pollutant measures (eg, PR per 84 µg/m3 increase in personal PM2.5 , 1.49; 95% confidence interval [CI], 1.11-2.01). Results for HbA1c as a continuous variable were generally in the hypothesized direction. These results provide some evidence linking household air pollution with the prevalence of prediabetes/diabetes, and, if confirmed, suggest that the global public health impact of household air pollution may be broader than currently estimated.

Trace aerosol detection and identification by dynamic photoacoustic spectroscopy.

Dynamic photoacoustic spectroscopy (DPAS) is a high sensitivity technique for standoff detection of trace vapors. A field-portable DPAS system has potential as an early warning provider for gaseous-based chemical threats. For the first time, we utilize DPAS to successfully detect the presence of trace aerosols. Aerosol identification via long-wavelength infrared (LWIR) spectra is demonstrated. We estimate the sensitivity of our DPAS system to aerosols comprised of silica particles is comparable to that of SF(6) gas based on a signal level per absorbance unit metric for the two materials. The implications of these measurements are discussed.

Impact of a cleaner-burning cookstove intervention on blood pressure in Nicaraguan women.

Few studies have evaluated the cardiovascular-related effects of indoor biomass burning or the role of characteristics such as age and obesity status, in this relationship. We examined the impact of a cleaner-burning cookstove intervention on blood pressure among Nicaraguan women using an open fire at baseline; we also evaluated heterogeneity of the impact by subgroups of the population. We evaluated changes in systolic and diastolic blood pressure from baseline to post-intervention (range: 273-383 days) among 74 female cooks. We measured indoor fine particulate matter (PM(2.5); N = 25), indoor carbon monoxide (CO; N = 32), and personal CO (N = 30) concentrations. Large mean reductions in pollutant concentrations were observed for all pollutants; for example, indoor PM(2.5) was reduced 77% following the intervention. However, pollution distributions (baseline and post-intervention) were wide and overlapping. Although substantial reductions in blood pressure were not observed among the entire population, a 5.9 mmHg reduction [95% confidence interval (CI): -11.3, -0.4] in systolic blood pressure was observed among women aged 40 or more years and a 4.6 mmHg reduction (95% CI: -10.0, 0.8) was observed among obese women. Results from this study provide an indication that certain subgroups may be more likely to experience improvements in blood pressure following a cookstove intervention.

α -event characterization and rejection in point-contact HPGe detectors.

P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector's response to α particles incident on the sensitive passivated and p + surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the Majorana Demonstrator experiment, a search for neutrinoless double-beta decay ( 0 ν ß ß ) in 76 Ge. α decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of α identification, reliably identifying α background events on the passivated surface of the detector. We demonstrate effective rejection of all surface α events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the 0 ν ß ß region of interest window by an order of magnitude in the Majorana Demonstrator  and will be used in the upcoming LEGEND-200 experiment.

Bile salt regulation of fatty acid absorption and esterification in rat everted jejunal sacs in vitro and into thoracic duct lymph in vivo.

This study was performed to investigate whether the malabsorption of fat in the blind loop syndrome is due to the presence of free bile acids or to a deficiency of conjugated bile salts produced by bacterial degradation of normal bile salts, as well as to learn something of the mechanisms by which bile salts might regulate fat absorption. In the everted gut sac of the rat in vitro, conjugated bile salts were necessary for maximal rates of fatty acid esterification to triglycerides, whereas free bile acids inhibited this process even in the presence of physiologically normal or higher concentrations of conjugated bile salts. In contrast, in the living animal the addition of similar or higher concentrations of free bile acids to infusions of fatty acids in taurocholate micellar solutions produced no reduction in the amount of fatty acid absorbed into lymph or the amount of fatty acid esterified into lymph triglyceride. Both in vitro and in the living animal, reduction in the conjugated bile salt concentration reduced both the rate of fatty acid uptake by the intestine and the esterification into triglycerides. It is concluded that the steatorrhea of the blind loop syndrome or other conditions in which upper intestinal stasis allows bacterial proliferation is not due to presence of increased gut luminal concentrations of free bile acids, but rather is a consequence of lowered concentrations of conjugated bile salts.

On the interconnectedness and prognostic value of visual and auditory hallucinations in first-episode psychosis.

BACKGROUND: Visual hallucinations (VH) are common symptoms in schizophrenia and other psychoses. An understanding of their cross-sectional and longitudinal patterns of association with auditory hallucinations (AH) is essential for developing accurate models of hallucinatory phenomena. OBJECTIVE: This study presents the most comprehensive examination of the association between VH and AH, and its change over time, in 1303 individuals with first-episode psychosis (FEP) and 469 individuals with chronic schizophrenia. METHOD: The samples included data from the WHO multicentre study on the Determinants of Outcome of Severe Mental Disorders and the Western Australian Family Study of Schizophrenia (WAFSS). Standardized assessment of symptoms and functioning were used to examine the clinical profile and symptom co-occurrence of hallucinations over time. RESULTS: VH were approximately half as frequent as AH, almost always co-occurred with AH, and tended to be linked to a more severe psychopathological profile. AH and VH at baseline also predicted higher disability, risk of relapse and duration of psychosis after 1 and 2 years, especially when occurring in combination. CONCLUSIONS: The findings point to three hallucination 'subtypes' with different symptom profile. The VH+AH combination signals greater psychopathology and a less favourable prognosis, than hallucinations occurring in isolation, and no hallucinations. This conclusion points to one common mechanism for all hallucinations, which can separate into distinct pathways and modalities. For a more complete clinical picture, clinicians should carefully probe for both auditory and VHs in presenting patients.

Chemical aerosol Raman detector.

A sensitive chemical aerosol Raman detector (CARD) has been developed for the trace detection and identification of chemical particles in the ambient atmosphere. CARD includes an improved aerosol concentrator with a concentration factor of about 40 and a CCD camera for improved detection sensitivity. Aerosolized isovanillin, which is relatively safe, has been used to characterize the performance of the CARD. The limit of detection (SNR = 10) for isovanillin in 15 s has been determined to be 1.6 pg/cm3, which corresponds to 6.3 × 109 molecules/cm3 or 0.26 ppb. While less sensitive, CARD can also detect gases. This paper provides a more detailed description of the CARD hardware and detection algorithm than has previously been published.

Effects of physiological hypercortisolemia on the regulation of lipolysis in subcutaneous adipose tissue.

Cortisol is known to increase whole body lipolysis, yet chronic hypercortisolemia results in increased fat mass. The main aim of the study was to explain these two apparently opposed observations by examining the acute effects of hypercortisolemia on lipolysis in subcutaneous adipose tissue and in the whole body. Six healthy subjects were studied on two occasions. On one occasion hydrocortisone sodium succinate was infused i.v. to induce hypercortisolemia (mean plasma cortisol concentrations, 1500 +/- 100 vs. 335 +/- 25 nmol/L; P < 0.001); on the other occasion (control study) no intervention was made. Lipolysis in the s.c. adipose tissue of the anterior abdominal wall was studied by measurement of arterio-venous differences, and lipolysis in the whole body was studied by constant infusion of [1,2,3-2H5]glycerol for measurement of the systemic glycerol appearance rate. Hypercortisolemia led to significantly increased arterialized plasma nonesterified fatty acid (NEFA; P < 0.01) and blood glycerol concentrations (P < 0.05), with an increase in systemic glycerol appearance (P < 0.05). However, in s.c. abdominal adipose tissue, hypercortisolemia decreased veno-arterialized differences for NEFA (P < 0.05) and reduced NEFA efflux (P < 0.05). This reduction was attributable to decreased intracellular lipolysis (P < 0.05), reflecting decreased hormone-sensitive lipase action in this adipose depot. Hypercortisolemia caused a reduction in arterialized plasma TAG concentrations (P < 0.05), but without a significant change in the local extraction of TAG (presumed to reflect the action of adipose tissue lipoprotein lipase). There was no significant difference in plasma insulin concentrations between the control and hypercortisolemia study. Site-specific regulation of the enzymes of intracellular lipolysis (hormone-sensitive lipase) and intravascular lipolysis (lipoprotein lipase) may explain the ability of acute cortisol treatment to increase systemic glycerol and NEFA appearance rates while chronically promoting net central fat deposition.

Self-induced water intoxication in schizophrenic patients.

The authors report on 21 cases of self-induced water intoxication and cite 25 others in the literature. Three of their patients demonstrated at least temporary inappropriate antidiuretic hormone secretion, 3 were receiving a diuretic, and the other 15 appeared to have "pure" water intoxication. Fifteen patients were receiving a psychotropic medication. Self-induced water intoxication appears to be more common in schizophrenic patients than is generally realized and should be suspected in any schizophrenic patient who develops convulsions or coma. Hyperdopaminergic CNS activity may be involved, and the authors suggest a possible mechanism similar to that for tardive dyskinesia.

Role of cigarette use in hyponatremia in schizophrenic patients.

Urine volume and osmolality were studied in two schizophrenic patients with hyponatremia and six normal subjects after they smoked or ingested cigarettes. The results suggest that cigarette use may contribute to the development of hyponatremia by impairing water excretion.

Immediate metabolic availability of dietary fat in combination with carbohydrate.

We tested the hypothesis that when fat is ingested in combination with carbohydrate, direct release of fatty acids into the plasma may occur. Eight normal subjects ingested two meals: high-fat (80 g fat, 80 g carbohydrate, and 18 g protein) and low-fat (< 1 g fat, otherwise closely matched). Over the subsequent 6 h, net fat oxidation was greater after the high-fat meal (20.7 vs 10.6 g, P < 0.01). Plasma nonesterified fatty acid (NEFA) concentrations were markedly suppressed after the low-fat meal, but relatively maintained after the high-fat meal (P < 0.01). The profile of plasma NEFAs changed after the high-fat meal, consistent with entry of meal-derived fatty acids into the NEFA pool. We suggest that after ingestion of combinations of carbohydrate and fat, the action of lipoprotein lipase on chylomicron-triacylglycerol leads to direct release of fatty acids into the plasma and increased fat oxidation.

A new model of human secretory diarrhoea using cholera toxin.

Secretory diarrhoea is a major cause of morbidity and mortality worldwide. However, there is no biologically relevant test system in man for assessing new anti-diarrhoeal therapies prior to clinical trial. We have used highly purified cholera toxin in combination with the triple lumen jejunal perfusion technique to establish a subclinical model of cholera in man. Cholera toxin was administered either by mouth with sodium bicarbonate or directly into a 30 cm 'open' or 'closed' (isolated between two inflated balloons) jejunal segment in healthy adult volunteers. Both oral dosing and direct delivery into an 'open' jejunal segment failed to produce consistent secretion of water and electrolytes. In contrast 15 micrograms or 25 micrograms of cholera toxin elicited secretion of water and sodium 3 h after instillation into the balloon occluded 'closed' jejunal segment (P less than 0.05 vs. controls). The rate of secretion was constant over the maximal period studied (4.5 h) and was similar to that reported in human cholera. None of the subjects experienced troublesome diarrhoea. We believe this model offers a relevant test system for assessing anti-diarrhoeal therapy in man.

Evidence that blockade of post-synaptic 5-HT1 receptors elicits feeding in satiated rats.

The effects of nine central 5-HT antagonists on food intake in free feeding male rats were examined. The 5-HT2 antagonists ritanserin and ketanserin and the selective 5-HT3 antagonists ICS 205-930 and MDL 72222 had no effect on food intake. In contrast, the non-selective 5-HT antagonists metergoline, methiothepin, mesulergine, mianserin and methysergide (all of which have high affinity for various 5-HT1 receptor subtypes), dose-dependently increased food intake during a 4-h daytime test. Furthermore, metergoline dose dependently increased food intake over a 24-h period. Surprisingly, mesulergine decreased food intake over a 24-h period at the same doses that increased daytime food intake. This may indicate that the increase in daytime feeding produced by mesulergine is a non-specific response. Although the antagonists used have varying degrees of selectivity for 5-HT receptor subtypes, the pattern of results suggests that postsynaptic 5-HT1 receptors (possibly of the 5-HT1C type) play an important role in the control of feeding in rats.