360 research outputs found
Constraining lepton number violating interactions in rare kaon decays
We investigate the possibility to probe lepton number violating (LNV) operators in the rare kaon decay K → πνν. Performing the analysis in the Standard Model effective field theory with only light active Majorana neutrinos, we determine the current limits
on the corresponding LNV physics scale from the past E949 experiment at BNL as well as
the currently operating experiments NA62 at CERN and KOTO at J-PARC. We focus on
the specific signature of scalar currents in K → πνν arising from the LNV nature of the
operators and study the effect on the experimental sensitivity, stressing the need for dedicated searches for beyond the SM currents. We find that the rare kaon decays probe high
operator scales ΛLNV ≈ 15 to 20 TeV in different quark and neutrino flavours compared to
neutrinoless double beta decay. Furthermore, we comment that the observation of LNV in
kaon decays can put high-scale leptogenesis under tension. Finally, we discuss the connection with small radiatively generated neutrino masses and show how the severe constraints
therefrom can be evaded in a minimal ultraviolet-complete scenario featuring leptoquarks
Implications of rare kaon decays on lepton number violating interactions
We explore the possibility of lepton number violation (LNV) manifesting in the rare kaon decay K→πνν, its consequences for radiative neutrino mass generation and the washout of lepton asymmetry in high-scale leptogenesis scenarios. We perform the analysis in a model-independent framework, the Standard Model effective field theory (SMEFT). Possibilities to detect the LNV nature of the rare kaon decay are discussed in the context of the currently operating NA62 experiment at CERN and the KOTO experiment at J-PARC. We find that LNV could be detectable, and that any such detection would put high-scale leptogenesis under tension but could account for small radiatively generated neutrino masses
Non-relativistic effective interactions of spin 1 Dark Matter
We investigate the non-relativistic reduction of simplified models for spin 1 dark matter (DM) with the aim of identifying features in the phenomenology of DM-quark interactions which are specific to vector DM. In the case of DM-quark interactions mediated by a spin 1 particle, we find two DM-nucleon interaction operators arising from the non-relativistic reduction of simplified models for spin 1 DM that are specific to spin 1 DM, and which were not considered in previous studies. They are quadratic in the momentum transfer, linear in a symmetric combination of polarisation vectors for the DM particle, and arise from simplified models which do not generate momentum transfer independent operators as leading interactions in the non-relativistic expansion of DM-nucleon scattering amplitudes. Within these simplified models, the new operators cannot be neglected when computing DM signals at direct detection experiments. For example, we find that nuclear recoil energy spectra computed by including or neglecting the new operators can differ by up to one order of magnitude for nuclear recoil energies larger than about 20 keV and DM masses below 50 GeV. Furthermore, the shape of the expected nuclear recoil spectra depends significantly on whether the new operators are taken into account or not. Finally, neglecting the contribution to DM direct detection signals from the new operators leads to inaccurate conclusions when assessing the compatibility of a future direct detection signal with CMB constraints on the DM relic density, especially when the number of signal events is small, e.g. O(1)
Distinguishing Dirac vs Majorana Neutrinos at CEνNS experiments
A transition magnetic moment between active and sterile neutrinos can induce the Primakoff upscattering process at the coherent elastic neutrino nucleus scattering experiments, leading to very stringent limits on the transition dipole coupling as a function of the sterile neutrino mass. Here we discuss how a novel radiative upscattering mode with an additional photon emitted in the final state can lead to exploration of new parameter space in the transition dipole coupling vs. sterile neutrino mass plane and provide distinguishable differential distributions for a Dirac vs Majorana sterile state mediating such a mode
Transition neutrino magnetic moments in CEνNS
Coherent Elastic Neutrino Nucleus Scattering (CEνNS) is a novel technique to look for new physics beyond the Standard Model. We study the prospects of probing a transition magnetic moment in CEνNS experiments. Showing the NUCLEUS experiment as an example, we demonstrate that properties of a potential sterile neutrino can be deduced
Broadened Allocation of Pancreas Transplants Across Compatible ABO Blood Types
Background
Current Organ Procurement and Transplantation Network (OPTN) policy restricts certain blood type-compatible simultaneous pancreas and kidney (SPK) transplants. Using the Kidney Pancreas Simulated Allocation Model, we examined the effects of 5 alternative allocation sequences that allowed all clinically compatible ABO transplants.
Methods
The study cohort included kidney (KI), SPK, and pancreas alone (PA) candidates waiting for transplant for at least 1 day between January 1, 2010, and December 31, 2010 (full cohort), and kidneys and pancreata recovered for transplant during the same period. Additionally, because the waiting list has shrunk since 2010, the study population was reduced by random sampling to match the volume of the 2015 waiting list (reduced cohort).
Results
Compared with the current allocation sequence, R4 and R5 both showed an increase in SPK transplants, a nearly corresponding decrease in KI transplants, and virtually no change in PA transplants. Life-years from transplant and median years of benefit also increased. The distribution of transplants by blood type changed, with more ABO:A, B, and AB transplants performed, and fewer ABO:O across all transplant types (KI, SPK, PA), with the relative percent changes largest for SPK.
Discussion
Broadened ABO compatibility allowances primarily benefitted SPK ABO:A and AB candidates. ABO:O candidates saw potentially reduced access to transplant. The simulation results suggest that modifying the current allocation sequence to incorporate broadened ABO compatibility can result in an increase in annual SPK transplants
Substance abuse and psychiatric co-morbidity as predictors of premature mortality in Swedish drug abusers a prospective longitudinal study 1970 - 2006
<p>Abstract</p> <p>Background</p> <p>Few longitudinal cohort studies have focused on the impact of substances abused and psychiatric disorders on premature mortality. The aim of the present study was to identify predictors of increased risk of drug related death and non drug related death in substance abusers of opiates, stimulants, cannabis, sedatives/hypnotics, hallucinogens and alcohol over several decades.</p> <p>Methods</p> <p>Follow-up study of a consecutive cohort of 561 substance abusers, admitted to a detoxification unit January 1970 to February 1978 in southern Sweden, and followed up in 2006. Demographic and clinical data, substance diagnoses and three groups of psychiatric diagnoses were identified at first admission. Causes of death were coded according to ICD-10 and classified as drug related deaths or non drug related deaths. To identify the incidence of some probable risk factors of drug related premature death, the data were subjected to a competing risks Cox regression analysis.</p> <p>Results</p> <p>Of 561 patients in the cohort, 11 individuals had either emigrated or could not be located, and 204/561 patients (36.4%) were deceased by 2006. The cumulative risk of drug related death increased more in the first 15 years and leveled out later on when non drug related causes of death had a similar incidence. In the final model, male gender, regular use of opiates or barbiturates at first admission, and neurosis were associated with an increased risk of drug related premature death, while cannabis use and psychosis were associated with a decreased risk. Neurosis, mainly depression and/or anxiety disorders, predicted drug related premature death while chronic psychosis and personality disorders did not. Chronic alcohol addiction was associated with increased risk of non drug related death.</p> <p>Conclusions</p> <p>The cohort of drug abusers had an increased risk of premature death to the age of 69. Drug related premature death was predicted by male gender, the use of opiates or barbiturates and depression and anxiety disorders at first admission. The predicted cumulative incidence of drug related death was significantly higher in opiate and barbiturate abusers over the observed period of 37 years, while stimulant abuse did not have any impact. Alcohol contributed to non drug related death.</p
Radiographers' involvement in research activities and opinions on radiography research: A Nordic survey
Introduction:Â Radiographers' engagement in research is important for the development of evidence-based practice in radiography; however, radiographers' interest in research has rarely been reported. This study sought to ascertain radiographers' opinions about radiography research and investigate their involvement in research activities in four Nordic countries.Methods:Â This study was conducted in Denmark, Finland, Norway and Sweden. A study-specific questionnaire was developed in English and adapted to each language of the study sample, and the content and face validity of the adaptations were evaluated. An online tool was used to collect the study data. The questionnaire link was distributed in September 2019 to radiographers working in clinical settings in four Nordic countries (n = 4572).Results:Â The overall response rate was 14% (n = 662/4572). Research involvement was reported by 33% of the respondents; data collection was the main type of contribution. Radiographers who contributed to research were more likely to be male, have longer work experience, hold a master's or doctoral degree, work as managers and be employed in university hospitals. Nearly all agreed that radiography research is needed to promote the radiography profession and provide the evidence base for radiographic practice. However, only 14% were aware of the current research evidence regarding their professional field of specialisation, and 19% indicated that they developed current practices based on research evidence.Conclusion:Â The findings indicate that, although radiographers had positive attitudes towards radiography research, their involvement in research and utilisation of research evidence in practice is low.</p
Poly-substance use and antisocial personality traits at admission predict cumulative retention in a buprenorphine programme with mandatory work and high compliance profile
Background: Continuous abstinence and retention in treatment for alcohol and drug use disorders are central challenges for the treatment providers. The literature has failed to show consistent, strong predictors of retention. Predictors and treatment structure may differ across treatment modalities. In this study the structure was reinforced by the addition of supervised urine samples three times a week and mandatory daily work/structured education activities as a prerequisite of inclusion in the program. Methods: Of 128 patients consecutively admitted to buprenorphine maintenance treatment five patients dropped out within the first week. Of the remaining 123 demographic data and psychiatric assessment were used to predict involuntary discharge from treatment and corresponding cumulative abstinence probability. All subjects were administered the Structured Clinical Interview for DSM-IV-TR, and the Symptom Checklist 90 (SCL-90), the Alcohol Use Disorder Identification Test (AUDIT), the Swedish universities Scales of Personality (SSP) and the Sense of Coherence Scale (SOC), all self-report measures. Some measures were repeated every third month in addition to interviews. Results: Of 123 patients admitted, 86 (70%) remained in treatment after six months and 61 (50%) remained in treatment after 12 months. Of those discharged involuntarily, 34/62 individuals were readmitted after a suspension period of three months. Younger age at intake, poly-substance abuse at intake (number of drugs in urine), and number of conduct disorder criteria on the SCID Screen were independently associated with an increased risk of involuntary discharge. There were no significant differences between dropouts and completers on SCL-90, SSP, SOC or AUDIT. Conclusion: Of the patients admitted to the programme 50% stayed for the first 12 months with continuous abstinence and daily work. Poly-substance use before intake into treatment, high levels of conduct disorder on SCID screen and younger age at intake had a negative impact on retention and abstinence
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