Highly Dispersive Electron Relaxation and Colossal Thermoelectricity in the Correlated Semiconductor FeSb2_2

We show that the colossal thermoelectric power, $S(T)$, observed in the correlated semiconductor FeSb$_2$ below 30\,K is accompanied by a huge Nernst coefficient $\nu(T)$ and magnetoresistance MR$(T)$. Markedly, the latter two quantities are enhanced in a strikingly similar manner. While in the same temperature range, $S(T)$ of the reference compound FeAs$_2$, which has a seven-times larger energy gap, amounts to nearly half of that of FeSb$_2$, its $\nu(T)$ and MR$(T)$ are intrinsically different to FeSb$_2$: they are smaller by two orders of magnitude and have no common features. With the charge transport of FeAs$_2$ successfully captured by the density functional theory, we emphasize a significantly dispersive electron-relaxation time $\tau(\epsilon_k)$ due to electron-electron correlations to be at the heart of the peculiar thermoelectricity and magnetoresistance of FeSb$_2$.Comment: 8 pages, 5 figure

Grindr Users Take More Risks, but Are More Open to Human Immunodeficiency Virus (HIV) Pre-exposure Prophylaxis: Could This Dating App Provide a Platform for HIV Prevention Outreach?

BackgroundTechnology has changed the way that men who have sex with men (MSM) seek sex. More than 60% of MSM in the United States use the internet and/or smartphone-based geospatial networking apps to find sex partners. We correlated use of the most popular app (Grindr) with sexual risk and prevention behavior among MSM.MethodsA nested cohort study was conducted between September 2018 and June 2019 among MSM receiving community-based human immunodeficiency virus (HIV) and sexually transmitted infection (STI) screening in central San Diego. During the testing encounter, participants were surveyed for demographics, substance use, risk behavior (previous 3 months), HIV pre-exposure prophylaxis (PrEP) use, and Grindr usage. Participants who tested negative for HIV and who were not on PrEP were offered immediate PrEP.ResultsThe study included 1256 MSM, 1090 of whom (86.8%) were not taking PrEP. Overall, 580 of 1256 (46%) participants indicated that they used Grindr in the previous 7 days. Grindr users reported significantly higher risk behavior (greater number of male partners and condomless sex) and were more likely to test positive for chlamydia or gonorrhea (8.6% vs 4.7% of nonusers; P = .005). Grindr users were also more likely to be on PrEP (18.7% vs 8.7% of nonusers; P < .001) and had fewer newly diagnosed HIV infections (9 vs 26 among nonusers; P = .014). Grindr users were also nearly twice as likely as nonusers to initiate PrEP (24.6% vs 14%; P < .001).ConclusionsGiven the higher risk behavior and greater acceptance of PrEP among MSM who used Grindr, Grindr may provide a useful platform to promote HIV and STI testing and increase PrEP uptake

A Parametrization for K+→π+π−e+νK^+\to \pi^+\pi^- e^+\nu

We discuss various models and Chiral Perturbation Theory results for the $K_{l4}$ form factors $F$ and $G$. We check in how much a simple parametrization with a few parameters can be used to extract information from experiment.Comment: 19 pages, 14 figure

Characterization of a Double Mesospheric Bore Over Europe

Observations of a pair of mesospheric bore disturbances that propagated through the nighttime mesosphere over Europe are presented. The observations were made at the Padua Observatory, Asiago (45.9\ub0N, 11.5\ub0E), by the Boston University all-sky imager on 11 March 2013. The bores appeared over the northwest horizon, approximately 30 min apart, and propagated toward the southeast. Using additional satellite and radar data, we present evidence indicating the bores originated in the mesosphere from a single, larger-scale mesospheric disturbance propagating through the mesopause region. Furthermore, the large-scale mesospheric disturbance appeared to be associated with an intense weather disturbance that moved southeastward over the United Kingdom and western Europe during 10 and 11 March

What do Eumerus Meigen larvae feed on? New immature stages of three species (Diptera: Syrphidae) breeding in different plants

The genus Eumerus Meigen 1822 (Diptera: Syrphidae) is widely distributed in the Old World, though recently introduced into America, and their larvae feed on decaying vegetal material and/or inside underground storage organs of many plants, sometimes generating economic losses as pests. However, little is known about Eumerus larval cycles and their interactions with host plants. Here, immatures of three Eumerus species from different continents are described, noting their feeding habits and host plants. Larvae of Eumerus figurans Walker 1859 were obtained from Hawaiian cultured ginger roots; puparium of Eumerus alpinus Rondani 1857 originated from larvae collected in Asphodelus ramosus L. in France; puparia of Eumerus superbus Shannon 1927 were reared from larvae found in two Zamiaceae species from Australia. Mitochondrial COI sequences served for diagnosing E. figurans larvae. Optical and scanning electron microscopy were used to describe body features, head skeletons, anterior spiracles, pupal spiracles, and posterior respiratory processes. Overall, E. alpinus resembles E. nudus Loew 1848 immatures. Eumerus superbus has a remarkable morphology among all described immatures of the genus, being the only Eumerus reported from gymnosperms. Head skeleton of E. figurans suggests this species is a filtering one. Present findings show that larvae of Eumerus can be separated at the species level and that this genus is polyphagous, feeding on a wide range of plant tissues and taxa, including commercial species. This study emphasizes immature stages and breeding sites as important means to understand species life cycles and the interactions with their host plants and ecosystems.This study is part of Gabriel J. Souba-Dols’ PhD thesis. His position at the University of Alicante (FPU-UA 2016), as well as that of Antonio Ricarte (Ref. UATAL05), are funded by the “Vicerrectorado de Investigación y Transferencia del Conocimiento.” Additionally, this research was partly funded by the Project PGC2018-095851-A-C65 of the Spanish Ministry of Science, Innovation and Universities

Studying the Transistor Using Wireless Epistemologies

The refinement of 802.11b is an essential prob- lem. Given the current status of autonomous theory, experts dubiously desire the simulation of the producer-consumer problem. We propose an approach for the visualization of sensor networks, which we call BREWIS

Shape of the spatial mode function of photons generated in noncollinear spontaneous parametric downconversion

We show experimentally how noncollinear geometries in spontaneous parametric downconversion induce ellipticity of the shape of the spatial mode function. The degree of ellipticity depends on the pump beam width, especially for highly focused beams. We also discuss the ellipticity induced by the spectrum of the pump beam

Soft tissue sarcomas at a glance: clinical, histological, and MR imaging features of malignant extremity soft tissue tumors

Soft tissue sarcomas comprise approximately 1% of malignant tumors. There are more than 50 subtypes, but pleomorphic sarcoma, liposarcoma, leiomyosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor account for 75%. Differentiation between these subtypes is difficult because they often present with a painless enlarging mass, and share many histological and MR imaging features. Nonetheless, subdifferentiation is important because the different subtypes have different prognoses and therapeutic strategies. In this manuscript we discuss the clinical, histological, and MR imaging features of soft tissue sarcomas according to the WHO classification. An overview is provided and differentiating features are discussed that can help to narrow down the differential diagnosis