Scalar Dark Matter Models with Significant Internal Bremsstrahlung

There has been interest recently on particle physics models that may give rise to sharp gamma ray spectral features from dark matter annihilation. Because dark matter is supposed to be electrically neutral, it is challenging to build weakly interacting massive particle models that may accommodate both a large cross section into gamma rays at, say, the Galactic center, and the right dark matter abundance. In this work, we consider the gamma ray signatures of a class of scalar dark matter models that interact with Standard Model dominantly through heavy vector-like fermions (the vector-like portal). We focus on a real scalar singlet S annihilating into lepton-antilepton pairs. Because this two-body final-state annihilation channel is d-wave suppressed in the chiral limit, we show that virtual internal bremsstrahlung emission of a gamma ray gives a large correction, both today and at the time of freeze-out. For the sake of comparison, we confront this scenario to the familiar case of a Majorana singlet annihilating into light lepton-antilepton pairs, and show that the virtual internal bremsstrahlung signal may be enhanced by a factor of (up to) two orders of magnitude. We discuss the scope and possible generalizations of the model.Comment: 25 pages, 10 figures, typos corrected, added references, matching version accepted by JCA

Signatures from Scalar Dark Matter with a Vector-like Quark Mediator

We present a comprehensive study of a model where the dark matter is composed of a singlet real scalar that couples to the Standard Model predominantly via a Yukawa interaction with a light quark and a colored vector-like fermion. A distinctive feature of this scenario is that thermal freeze-out in the early universe may be driven by annihilation both into gluon pairs at one-loop ($gg$) and by virtual internal Bremsstrahlung of a gluon ($q \bar{q} g$). Such a dark matter candidate may also be tested through direct and indirect detection and at the LHC; viable candidates have either a mass nearly degenerate with that of the fermionic mediator or a mass above about 2 TeV.Comment: 30 pages, 10 figures. Matches published versio

Parylene-membrane piezoresistive pressure sensors with XeF_2-etched cavity

Pressure sensors have been fabricated based on a deformable parylene C membrane over a cavity etched in silicon. The cavity is obtained by XeF_2 etching, using a parylene mask composed of an array of holes. A subsequent parylene deposition fills the holes, thus sealing the cavity and completing the membrane. Gold piezoresistors are used to sense the membrane deformation. Compared to traditional pressure sensor designs, this process is more easily integrated into other processes, as no double-side machining or wet silicon etching is needed. The use of parylene is advantageous under certain points of view. First, it protects the piezoresistors and silicon, due to its well known barrier and chemical inertness properties. Second, contrary to other materials commonly used to fabricate pressure sensor membranes (e.g., polysilicon, silicon nitride), parylene is flexible, and thus more resistant to shocks. These two reasons make the sensor useful in chemically and physically harsh environments

Electrolysis-based parylene-balloon actuators

This work reports the design, fabrication, testing and modeling of electrolysis-based fully encapsulated parylene balloon actuators. The proposed actuators have the advantage of high force at low power and low voltage. The main issues are low actuation speed and limited number of actuation cycles due to loss of water by permeation through the balloon membrane. In our case, the actuators are targeted to move neuroprobes after implantation, where slow movement is acceptable but low power consumption is of demand

Maternal and neonatal complications following Kielland's rotational forceps delivery: A systematic review and meta‐analysis

Background There is conflicting evidence regarding the safety of Kielland's rotational forceps delivery (KRFD) in comparison with other modes of delivery for the management of persistent fetal malposition in the second stage of labour. Objectives To derive estimates of risks of maternal and neonatal complications following KRFD, compared with rotational ventouse delivery (RVD), non-rotational forceps delivery (NRFD) or a second-stage caesarean section (CS), from a systematic review and meta-analysis of the literature. Search Strategy Standard search methodology, as recommended by the Cochrane Handbook for Systematic Reviews of Interventions. Selection Criteria Case series, prospective or retrospective cohort studies and population-based studies. Data Collection and Analysis A meta-analysis using a random-effects model was used to derive weighted pooled estimates of maternal and neonatal complications. Main Results Thirteen studies were included. For postpartum haemorrhage there was no significant difference between Kielland's and ventouse delivery; the rate was lower in Kielland's delivery compared with non-rotational forceps (RR 0.79, 95% CI 0.65–0.95) and second-stage CS (RR 0.45, 95% CI 0.36–0.58). There were no differences in the rates of anal sphincter injuries or admission to neonatal intensive care. Rates of shoulder dystocia were higher with Kielland's delivery compared with ventouse delivery (RR 1.79, 95% CI 1.08–2.98), but rates of neonatal birth trauma were lower (RR 0.49, 95% CI 0.26–0.91). There were no differences seen in the rates of 5-min APGAR score < 7 between Kielland's delivery and other instrumental births, but they were lower when compared with second-stage CS (RR 0.47, 95% CI 0.23–0.97). Conclusions Kielland's rotational forceps delivery is a safe option for the management of fetal malposition in the second stage of labour

Top-philic Vector-Like Portal to Scalar Dark Matter

We investigate the phenomenology of scalar singlet dark matter candidates that couple dominantly to the Standard Model via a Yukawa interaction with the top quark and a colored vector-like fermion. We estimate the viability of this vector-like portal scenario with respect to the most recent bounds from dark matter direct and indirect detection, as well as to dark matter and vector-like mediator searches at colliders. Moreover, we take QCD radiative corrections into account in all our theoretical calculations. This work complements analyses related both to models featuring a scalar singlet coupled through a vector-like portal to light quarks, and to scenarios in which the dark matter is a Majorana singlet coupled to the Standard Model through scalar colored particles (akin to simplified models inspired by supersymmetry). Our study puts especially forward the complementarity of different search strategies from different contexts, and we show that current experiments allow for testing dark matter masses ranging up to 700 GeV and mediator masses ranging up to 6 TeV.Comment: 15 pages, 11 figures; version accepted by PR

The violated body, the released body: self-destruction and catharsis in La Muñeca menor by Rosario Ferré

The theory of self-recognition of the female universe elaborated by Hélène Cixous in the essay The laugh of the Medusa1975) together with the mechanisms of postcolonial alienation analyzed by Franz Fanon in The Damned of the Earth (1961) have, in my opinion, inspired Rosario Ferré in the elaboration of the literary strategies adopted in her short story La Muñeca menor. Ferré’s intention is to demystify and overturn the patriarchal system in force through an autobiographical, subversive, and angry writing. The rebellion of the female heroines is accomplished through catharsis and the consumption of their bodies. Their liberating self-destruction opens the way to a real decolonization of the soul. The Puerto Rican author aims to highlight in the short story the emotional repercussions generated by colonial processes. Rosario Ferré also theorizes a new cosmogony in which Puerto Rican women, doubly victims of the colonial and patriarchal system, can play a more active and participatory role.La teoria sull’auto-riconoscimento dell’universo femminile elaborata da Hélène Cixous nel saggio La Risa de la Medusa (1975) unitamente ai meccanismi di alienazione postcoloniale analizzati da Franz Fanon ne I Dannati della terra (1961) hanno, a mio avviso, ispirato Rosario Ferré nell’elaborazione delle strategie letterarie adottate nel racconto La Muñeca menor. L’intento di Ferré è quello di demistificare e rovesciare il sistema patriarcale vigente attraverso una scrittura autobiografica, sovversiva e iraconda. La ribellione che caratterizza le eroine femminili de La Muñeca menor si compie attraverso la catarsi e la consunzione dei loro corpi. La loro autodistruzione liberatoria apre la strada a una vera e propria decolonizzazione dell’anima. La scrittrice portoricana si prefigge di mettere in luce attraverso il racconto le ripercussioni emotive generate dai processi coloniali. Ferré teorizza inoltre una nuova cosmogonia in cui le donne portoricane, doppiamente vittime del sistema coloniale e patriarcale, possano rivestire un ruolo attivo e partecipativo

Il corpo violato, il corpo liberato: autodistruzione e catarsi in La Muñeca menor di Rosario Ferré

La teoria sull’auto-riconoscimento dell’universo femminile elaborata da Hélène Cixous nel saggio La Risa de la Medusa (1975) unitamente ai meccanismi di alienazione postcoloniale analizzati da Franz Fanon ne I Dannati della terra (1961) hanno, a mio avviso, ispirato Rosario Ferré nell’elaborazione delle strategie letterarie adottate nel racconto La Muñeca menor. L’intento di Ferré è quello di demistificare e rovesciare il sistema patriarcale vigente attraverso una scrittura autobiografica, sovversiva e iraconda. La ribellione che caratterizza le eroine femminili de La Muñeca menor si compie attraverso la catarsi e la consunzione dei loro corpi. La loro autodistruzione liberatoria apre la strada a una vera e propria decolonizzazione dell’anima. La scrittrice portoricana si prefigge di mettere in luce attraverso il racconto le ripercussioni emotive generate dai processi coloniali. Ferré teorizza inoltre una nuova cosmogonia in cui le donne portoricane, doppiamente vittime del sistema coloniale e patriarcale, possano rivestire un ruolo attivo e partecipativo.The theory of self-recognition of the female universe elaborated by Hélène Cixous in the essay The laugh of the Medusa1975) together with the mechanisms of postcolonial alienation analyzed by Franz Fanon in The Damned of the Earth (1961) have, in my opinion, inspired Rosario Ferré in the elaboration of the literary strategies adopted in her short story La Muñeca menor. Ferré’s intention is to demystify and overturn the patriarchal system in force through an autobiographical, subversive, and angry writing. The rebellion of the female heroines is accomplished through catharsis and the consumption of their bodies. Their liberating self-destruction opens the way to a real decolonization of the soul. The Puerto Rican author aims to highlight in the short story the emotional repercussions generated by colonial processes. Rosario Ferré also theorizes a new cosmogony in which Puerto Rican women, doubly victims of the colonial and patriarchal system, can play a more active and participatory role

Incidence of vasa praevia: a systematic review and meta-analysis.

Objectives To derive accurate estimates of the incidence of vasa praevia (VP) in a routine population of unselected pregnancies. Design Systematic review and meta-analysis. Data sources A search of MEDLINE, EMBASE, CINAHL and the Cochrane database was performed to review relevant citations reporting outcomes in pregnancies with VP from January 2000 until 5 April 2023. Eligibility criteria for selection of studies Prospective or retrospective cohort or population studies that provided data regarding VP cases in routine unselected pregnancies during the study period. We included studies published in the English language after the year 2000 to reflect contemporary obstetric and neonatal practice. Data extraction and synthesis Two reviewers independently screened the retrieved citations and extracted data. The methodological quality of studies was assessed using the Newcastle–Ottawa Scale, and Preferred Reporting Items for Systematic reviews and Meta-Analyses was used to ensure standardised reporting of studies. Results A total of 3847 citations were screened and 82 full-text manuscripts were retrieved for analysis. There were 24 studies that met the inclusion criteria, of which 12 studies reported prenatal diagnosis with a systematic protocol of screening. There were 1320 pregnancies with VP in a total population of 2 278 561 pregnancies; the weighted pooled incidence of VP was 0.79 (95% CI: 0.59 to 1.01) per 1000 pregnancies, corresponding to 1 case of VP per 1271 (95% CI: 990 to 1692) pregnancies. Nested subanalysis of studies reporting screening for VP based on a specific protocol identified 395 pregnancies with VP in a population of 732 654 pregnancies with weighted pooled incidence of 0.82 (95% CI: 0.53 to 1.18) per 1000 pregnancies (1 case of VP per 1218 (95% CI: 847 to 1901) pregnancies). Conclusion The incidence of VP in unselected pregnancies is 1 in 1218 pregnancies. This is higher than is previously reported and can be used as a basis to assess whether screening for this condition should be part of routine clinical practice. Incorporation of strategies to screen for VP in routine clinical practice is likely to prevent 5% of stillbirths