Dark Sector Physics with Belle II Corona, L
Journal of physics. Conference series,
04/2020, Letnik:
1526, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The Belle II experiment at the SuperKEKB energy-asymmetric e+e− collider is a substantial upgrade of the KEKB facility at the Japanese KEK laboratory. The design luminosity of the machine is 8 · 1035 ...cm−2s−1 and the Belle II experiment aims to record 50 ab−1 of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, where about 0.5 fb−1 of data have been collected. Regular operation of SuperKEKB has started in March 2019: the machine has achieved a peak luminosity of 1034 cm−2s−1, and Belle II has recorded a data sample of about 6.5 fb−1. Already this early data set with specifically designed triggers offers the possibility to search for a large variety of dark sector particles in the GeV mass range complementary to searches at LHC and dedicated low energy experiments. The Belle II dark matter analyses will benefit from more data in the process of being accumulated. This talk will review the state of the dark sector searches at Belle II with a focus on the discovery potential of the early data, and show the first results.
Proton–hydride tautomerism in hydrogen evolution catalysis Quintana, Luis M. Aguirre; Johnson, Samantha I.; Corona, Sydney L. ...
Proceedings of the National Academy of Sciences - PNAS,
06/2016, Letnik:
113, Številka:
23
Journal Article
Recenzirano
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Efficient generation of hydrogen from renewable resources requires development of catalysts that avoid deep wells and high barriers. Information about the energy landscape for H₂ production can be ...obtained by chemical characterization of catalytic intermediates, but few have been observed to date. We have isolated and characterized a key intermediate in 2e⁻ + 2H⁺ → H₂ catalysis. This intermediate, obtained by treatment of Cp*Rh(bpy) (Cp*, η⁵-pentamethylcyclopentadienyl; bpy, κ²-2,2′-bipyridyl) with acid, is not a hydride species but rather, bears η⁴-Cp*H as a ligand. Delivery of a second proton to this species leads to evolution of H₂ and reformation of η⁵-Cp* bound to rhodium(III). With suitable choices of acids and bases, the Cp*Rh(bpy) complex catalyzes facile and reversible interconversion of H⁺ and H₂.
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► The carbon cloth electrode adsorbs a significant quantity of hydrocarbons during the electrokinetic process. ► The Ti|IrO2–Ta2O5 electrode was a good material for electro-oxidate ...organic compounds. ► The electrodes in direct contact with the polluted soil were better than those separated by a physical barrier, because it increased the efficiency of the electrokinetic process.
There are diverse alternatives for treating polluted soil. However, one of the most promising and innovating technologies is the electrokinetic remediation process. In the electrokinetic process, pollutant removal is influenced by several factors such as the material used as electrodes and their arrangement in the electrokinetic system, among others.
This paper investigates the feasibility of removing hydrocarbon from a polluted soil, analyzing first some properties of different electrode materials by electrochemical techniques for the purpose of selecting the best to be used as an anode in the electrokinetic process. Also, two different cathode materials were tested during the electrokinetic remediation process – carbon cloth and titanium. However, results indicated the carbon cloth adsorbed the organic compounds; for that reason, it was discarded from the electrokinetic remediation process.
In addition, two electrode arrangements were evaluated in the electrokinetic system, those where the electrodes were in direct contact with the soil and those where the electrodes were separated from soil by a physical barrier. The first array showed less electrical resistance and more hydrocarbon removal than the second.
Families of young children with autism spectrum disorder (ASD) frequently experience barriers to accessing evidence-based early intervention services. Telemedicine presents an opportunity to increase ...access to these services, particularly for families in rural and under-resourced areas. The present article describes a brief behavioral intervention and support model for families of young children with concerns for ASD. In the context of the COVID-19 pandemic, this service model shifted to telemedicine-only service delivery, resulting in an opportunity to analyze intervention outcomes from services delivered either via traditional in-person visits, telemedicine-only sessions, or a hybrid model including both in-person and telemedicine sessions.
Data are presented for 115 families with toddlers 16-33 months of age who participated in a six-session behavioral intervention and support service model either in-person, through telemedicine, or through a hybrid service model. This intervention was available for families referred for ASD evaluation through the state Part C early intervention program. Intervention feasibility, fidelity of implementation, child outcomes, and stakeholder satisfaction are compared across service delivery models.
Caregivers, behavioral consultants, and Part C early intervention providers reported satisfaction with services, regardless of service delivery model. Caregivers and consultants also reported positive child outcomes. Statistically significant differences emerged for caregiver- and consultant-reported child outcomes in some domains, with stakeholders in the telemedicine-only group reporting slightly less improvement, compared to stakeholders in the in-person-only group. Caregivers and consultants in the telemedicine-only group also provided qualitative feedback on benefits and challenges related to telemedicine services.
Both caregivers and behavioral consultants reported positive outcomes following a brief behavioral intervention and support model targeted at families of young children with concern for ASD. Stakeholders reported improvement in child behavior and satisfaction with services across in-person, telemedicine-only, and hybrid models of service delivery. These results suggest that telemedicine presents a promising opportunity for increasing service access. Additional research is needed to continue optimizing the experience of telemedicine-based service delivery for both families and intervention providers.
The DMAPS upgrade of the Belle II vertex detector Babeluk, M.; Barbero, M.; Baudot, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2024, Letnik:
1064
Journal Article
Recenzirano
The Belle II experiment at KEK in Japan considers an upgrade for the vertex detector system in line with the accelerator upgrade for higher luminosity at long shutdown 2 planned for 2028.
One ...proposal for the upgrade of the vertex detector called VTX aims to improve background robustness and reduce occupancy using small and fast pixels. VTX accommodates the OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) on all five proposed layers. OBELIX is specifically developed for the VTX application and based on the TJ-Monopix2 chip initially developed to meet the requirements of the outer layers of the ATLAS inner tracker (ITk).
This paper will review recent tests of the TJ-Monopix2 chip as well as various design aspects of the OBELIX-1 chip currently under development.
This study evaluated the association between anorexia of aging and nutrients intake. It was a cross-sectional study with 130 individuals aged 60 years or older, undergoing outpatient care in the city ...of Campinas, São Paulo. Anorexia of Aging (AA) was assessed using the Simplified Nutrition Appetite Questionnaire (SNAQ), and food consumption was evaluated using the 24-hour recall (24HR). The prevalence of AA was 27.7%, in which 66.7% were women and 38.9% were older than 80 years. Elderly with AA presented lower intake of calories (1172.6 kcal vs 1477.9 kcal; p = 0.003), carbohydrates (158.5 g vs 194.1 g; p = 0.015), proteins (49.9 g vs 68.5 g; p = 0.004) and lipids (34.6 g vs 46.1 g; p = 0.006). They also had lower intake of fibers (12.6 g vs 19.4 g; p < 0.001), iron (6.4 mg vs 8.9 mg; p < 0.001) and zinc (6.0 mg vs 8.5 mg; p = 0.004). Our results show that intake of most nutrients is significantly lower in AA elderly, except carbohydrates, which may point to worse-quality diets. The diagnosis of AA, as well as the evaluation of elderly food intake, are essential to prevent undernutrition, vulnerabilities, and increased morbidity and mortality.
The OBELIX chip for the Belle II VTX upgrade Babeluk, M.; Auguste, D.; Barbero, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
October 2024, Letnik:
1067
Journal Article
Recenzirano
The OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) is currently developed for the upgrade of the vertex detector of the Belle II experiment located at Tsukuba/Japan. The pixel matrix of ...OBELIX is inherited from the TJ-Monopix2 chip, but the periphery includes additional features to improve performance and allow the integration into a larger detector system. The new features include a trigger unit to process trigger signals, a precision timing module and a possibility to transmit low granularity hit information with low latency to contribute to the Belle II trigger. Additionally, low dropout voltage regulators and an ADC to monitor power consumption and substrate temperature is developed. This paper will focus on the trigger contribution capabilities of the OBELIX chip.
The Belle II experiment searches for beyond-the-standard-model physics using the Belle II detector and SuperKEKB collider. The silicon vertex detector (SVD) is crucial for particle tracking. After ...the 1.5-year shutdown from June 2022, Run 2 began in January 2024; Run 2 operation shows stable noise levels, high signal-to-noise ratios, and hit efficiency over 99%. To manage higher beam background from increased luminosity, new techniques such as hit-time selection and cluster grouping are being developed. These methods increase the acceptable level of occupancy by distinguishing hits from triggered collisions and other sources.
A 3D print device using a cold metal transfer arc welding station to melt a metallic filler wire is developed to build aluminium part by optimising the process parameters. First tests achieved using ...standard pre-recorded process parameters allow to study the effect of the travel speed and the average welding power on the geometrical characteristics of mono-layer deposits and on walls built by layers superposition. Finally, a parametric study of the effect of each process parameter controlling the shape of the arc current or voltage and the filler wire feeding is carried out in order to try to improve the geometrical regularity of the deposits, and to better understand the effect of each parameter on the melting of the filler wire, its transfer on the support plate, and the geometry of the formed bead.
Pelvic floor muscle stretch injury during pregnancy and birth is associated with the incidence of stress urinary incontinence (SUI), a condition that affects 30-60% of the female population and is ...characterized by involuntary urine leakage during physical activity, further exacerbated by aging. Aging and multiparous rabbits suffer pelvic nerve and muscle damage, resulting in alterations in pelvic floor muscular contraction and low urethral pressure, resembling SUI. However, the extent of nerve injury is not fully understood. Here, we used electron microscopy analysis of pelvic and perineal nerves in multiparous rabbits to describe the extent of stretch nerve injury based on axon count, axon size, myelin-to-axon ratio, and elliptical ratio. Compared to young nulliparous controls, mid-age multiparous animals showed an increase in the density of unmyelinated axons and in myelin thickness in both nerves, albeit more significant in the bulbospongiosus nerve. This revealed a partial but sustained damage to these nerves, and the presence of some regenerated axons. Additionally, we tested whether electrical stimulation of the bulbospongiosus nerve would induce muscle contraction and urethral closure. Using a miniature wireless stimulator implanted on this perineal nerve in young nulliparous and middle age multiparous female rabbits, we confirmed that these partially damaged nerves can be acutely depolarized, either at low (2-5 Hz) or medium (10-20 Hz) frequencies, to induce a proportional increase in urethral pressure. Evaluation of micturition volume in the mid-age multiparous animals after perineal nerve stimulation, effectively reversed a baseline deficit, increasing it 2-fold (p = 0.02). These results support the notion that selective neuromodulation of pelvic floor muscles might serve as a potential treatment for SUI.
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