Measurement of the 2νββ Decay Rate and Spectral Shape of ^{100}Mo from the CUPID-Mo Experiment

Neutrinoless double beta decay (0νββ) is a yet unobserved nuclear process that would demonstrate Lepton number violation, a clear evidence of beyond standard model physics. The process two neutrino double beta decay (2νββ) is allowed by the standard model and has been measured in numerous experiments. In this Letter, we report a measurement of 2νββ decay half-life of ^{100}Mo to the ground state of ^{100}Ru of [7.07±0.02(stat)±0.11(syst)]×10^{18}  yr by the CUPID-Mo experiment. With a relative precision of ±1.6% this is the most precise measurement to date of a 2νββ decay rate in ^{100}Mo. In addition, we constrain higher-order corrections to the spectral shape, which provides complementary nuclear structure information. We report a novel measurement of the shape factor ξ_{3,1}=0.45±0.03(stat)±0.05(syst) based on a constraint on the ratio of higher-order terms from theory, which can be reliably calculated. This is compared to theoretical predictions for different nuclear models. We also extract the first value for the effective axial vector coupling constant obtained from a spectral shape study of 2νββ decay.

New Limit for Neutrinoless Double-Beta Decay of ^{100}Mo from the CUPID-Mo Experiment

The CUPID-Mo experiment at the Laboratoire Souterrain de Modane (France) is a demonstrator for CUPID, the next-generation ton-scale bolometric 0νββ experiment. It consists of a 4.2 kg array of 20 enriched Li_{2}^{100}MoO_{4} scintillating bolometers to search for the lepton-number-violating process of 0νββ decay in ^{100}Mo. With more than one year of operation (^{100}Mo exposure of 1.17  kg×yr for physics data), no event in the region of interest and, hence, no evidence for 0νββ is observed. We report a new limit on the half-life of 0νββ decay in ^{100}Mo of T_{1/2}>1.5×10^{24}  yr at 90% C.I. The limit corresponds to an effective Majorana neutrino mass ⟨m_{ββ}⟩<(0.31-0.54)  eV, dependent on the nuclear matrix element in the light Majorana neutrino exchange interpretation.

Maxillofacial fracture epidemiology and treatment plans in the Northeast of Iran: A retrospective study

Background

The epidemiology of facial injuries varies based on lifestyle, cultural background and socioeconomic status in different countries and geographic zones. This study evaluated the epidemiology of maxillofacial fractures and treatment plans in hospitalized patients in Northeast of Iran (2015-2016).

Material and Methods

In this retrospective study, the medical records of 502 hospitalized patients were evaluated in the Department of Maxillofacial Surgery in Kamyab Hospital in Mashhad, Iran. The type and cause of fractures and treatment plans were recorded in a checklist. Data were analyzed with Mann–Whitney test, chi-squared test and Fisher’s exact test, using SPSS 21.

Results

The majority of patients were male (80.3%). Most subjects were in 20-30-year age range (43.2%). The fractures were mostly caused by accidents, particularly motorcycle accidents (MCAs), and the most common site of involvement was the body of the mandible. There was a significant association between the type of treatment and age. In fact, the age range of 16-59 years underwent open reduction internal fixation (ORIF) more than other age ranges (P=0.001). Also, there was a significant association between gender and fractures (P=0.002).

Conclusions

It was concluded that patient age and gender and trauma significantly affected the prevalence of maxillofacial traumas, fracture types and treatment plans. This information would be useful for making better health policy strategies.

Key words:Epidemiology, treatment, facial injuries, maxillofacial fractures, trauma.

[Breech extraction of the second twin. 56 cases and review of the literature]

The best indication for breech extraction, and undoubtedly the last, is for delivery of the second twin with a non-cephalic presentation. At the Besançon University Hospital, we have used this technique routinely and without delay in case of non-cephalic presentation of the second twin. In order to evaluate the results of this approach, we studied 56 patients files retrospectively in a continuous series of case over a 7-year period. The following data were noted: birthweights, APGAR score at 5 minutes, requirement for paediatric intensive care, hospitalization in paediatric ward, and death. Gestational age and rate of prematurity were calculated. We also recorded the rate and type of antalgisia used, as well as the frequency of episiotomy. Both the obstetrical and neonatal results indicated that breech extraction of the second twin is a reliable effective technique in terms of mortality and morbidity for the second twin. Using this technique should not raise any legal problems since the other techniques for delivering the second twin have not been shown to give better results. When planned and performed under precise conditions by an experimented physician, this route does not give any poorer results than cesarean. Breech extraction should be an exceptional technique all obstetricians can use, together with cesarean, for delivering the second twin.