Constraining pre Big-Bang-Nucleosynthesis Expansion using Cosmic Antiprotons

A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity tests, may nevertheless lead to enhancements of the Hubble rate up to many orders of magnitude. In this paper we show that strong bounds on the pre-BBN evolution of the Universe may be derived, under the assumption that dark matter is a thermal relic, by combining the dark matter relic density bound with constraints coming from the production of cosmic-ray antiprotons by dark matter annihilation in the Galaxy. The limits we derive can be sizable and apply to the Hubble rate around the temperature of dark matter decoupling. For dark matter masses lighter than 100 GeV, the bound on the Hubble-rate enhancement ranges from a factor of a few to a factor of 30, depending on the actual cosmological model, while for a mass of 500 GeV the bound falls in the range 50-500. Uncertainties in the derivation of the bounds and situations where the bounds become looser are discussed. We finally discuss how these limits apply to some specific realizations of non-standard cosmologies: a scalar-tensor gravity model, kination models and a Randall-Sundrum D-brane model.Comment: 19 pages, 15 figures, LaTex, uses revtex

Solanum malmeanum, a promising wild relative for potato breeding.

Solanum malmeanum (Solanum sect. Petota, Solanaceae) é um parente silvestre da batata (S. tuberosum), nativo do Cone Sul da América do Sul, com ocorrência na Argentina, Brasil, Paraguai e Uruguai. S. malmeanum foi historicamente confundida ou tradicionalmente considerada coespecífica com S. commersonii, tornando-a negligenciada quanto a estudos aplicados de uso no melhoramento. Com o objetivo de elucidar o potencial da espécie e fornecer bases para promover o use deste recurso genético no melhoramento, a dissertação está organizada em dois capítulos. O Capítulo 1 apresenta uma revisão de literatura, de espécimes de herbários e de bancos de germoplasma. As informações disponíveis foram atualizadas, de modo a facilitar o reconhecimento e dar apoio para a utilização desse parente silvestre nos programas de melhoramento. São apresentados dados sobre taxonomia, distribuição geográfica, ecologia, biologia reprodutiva, e informações de resistência aos estresses bióticos e abióticos. Além disso, são discutimos métodos para superar as barreiras reprodutivas e de hibridação, visando o uso aplicado nos programas de melhoramento de batata. O Capítulo 2 apresenta estudos de biologia reprodutiva e hibridações intra e interespecíficas controladas com base em acessos do Banco Ativo de Germoplasma de Batata da Embrapa Clima Temperado.Dissertação (Mestrado em Ciências) - Universidade Federal de Pelotas. Orientador: Gustavo Heiden (CPACT); Coorientadora: Caroline Marques Castro (CPACT)

Dynamics of systems with isotropic competing interactions in an external field: a Langevin approach

We study the Langevin dynamics of a ferromagnetic Ginzburg-Landau Hamiltonian with a competing long-range repulsive term in the presence of an external magnetic field. The model is analytically solved within the self consistent Hartree approximation for two different initial conditions: disordered or zero field cooled (ZFC), and fully magnetized or field cooled (FC). To test the predictions of the approximation we develop a suitable numerical scheme to ensure the isotropic nature of the interactions. Both the analytical approach and the numerical simulations of two-dimensional finite systems confirm a simple aging scenario at zero temperature and zero field. At zero temperature a critical field $h_c$ is found below which the initial conditions are relevant for the long time dynamics of the system. For $h < h_c$ a logarithmic growth of modulated domains is found in the numerical simulations but this behavior is not captured by the analytical approach which predicts a $t^1/2$ growth law at $T = 0$

Solanum malmeanum, a promising wild relative for potato breeding.

Crop wild relatives are gaining increasing attention. Their use in plant breeding is essential to broaden the genetic basis of crops as well as to meet industrial demands, for global food security and sustainable production. Solanum malmeanum (Solanum sect. Petota, Solanaceae) is a wild relative of potatoes (S. tuberosum) from Southern South America, occurring in Argentina, Brazil, Paraguay and Uruguay. This wild potato has been largely mistaken for or historically considered as conspecific with S. commersonii. Recently, it was reinstated at the species level. Retrieving information on its traits and applied uses is challenging, because the species name has not always been applied correctly and also because species circumscriptions and morphological criteria applied to recognize it have not been consistent. To overcome these difficulties, we performed a thorough literature reference survey, herbaria specimens? identification revision and genebank database queries to review and update the information available on this potato wild relative, contributing to an increase in research on it to fully understand and explore its potential for potato breeding. Scarce studies have been carried out concerning its reproductive biology, resistance against pests and diseases as well as tolerance to abiotic stresses and evaluation of quality traits. The scattered information available makes it less represented in genebanks and genetic studies are missing. We compile, update and present available information for S. malmeanum on taxonomy, geographical distribution, ecology, reproductive biology, relationship with its closest relatives, biotic and abiotic stresses resistance and quality traits and discuss ways to overcome sexual barriers of hybridization and future perspectives for its use in potato breeding. As a final remark, we highlight that this species? potential uses have been neglected and must be unlocked. Thus, further studies on morphological and genetic variability with molecular tools are fundamental for an efficient conservation and applied use of this promising genetic resource.Online first 20 February 2023

Modeling vaccination rollouts, SARS-CoV-2 variants and the requirement for non-pharmaceutical interventions in Italy

Despite progress in clinical care for patients with coronavirus disease 2019 (COVID-19)1, population-wide interventions are still crucial to manage the pandemic, which has been aggravated by the emergence of new, highly transmissible variants. In this study, we combined the SIDARTHE model2, which predicts the spread of SARS-CoV-2 infections, with a new data-based model that projects new cases onto casualties and healthcare system costs. Based on the Italian case study, we outline several scenarios: mass vaccination campaigns with different paces, different transmission rates due to new variants and different enforced countermeasures, including the alternation of opening and closure phases. Our results demonstrate that non-pharmaceutical interventions (NPIs) have a higher effect on the epidemic evolution than vaccination alone, advocating for the need to keep NPIs in place during the first phase of the vaccination campaign. Our model predicts that, from April 2021 to January 2022, in a scenario with no vaccine rollout and weak NPIs (R = 1.27), as many as 298,000 deaths associated with COVID-19 could occur. However, fast vaccination rollouts could reduce mortality to as few as 51,000 deaths. Implementation of restrictive NPIs (R = 0.9) could reduce COVID-19 deaths to 30,000 without vaccinating the population and to 18,000 with a fast rollout of vaccines. We also show that, if intermittent open\u2013close strategies are adopted, implementing a closing phase first could reduce deaths (from 47,000 to 27,000 with slow vaccine rollout) and healthcare system costs, without substantive aggravation of socioeconomic losses

Observability and nonlinear filtering

This paper develops a connection between the asymptotic stability of nonlinear filters and a notion of observability. We consider a general class of hidden Markov models in continuous time with compact signal state space, and call such a model observable if no two initial measures of the signal process give rise to the same law of the observation process. We demonstrate that observability implies stability of the filter, i.e., the filtered estimates become insensitive to the initial measure at large times. For the special case where the signal is a finite-state Markov process and the observations are of the white noise type, a complete (necessary and sufficient) characterization of filter stability is obtained in terms of a slightly weaker detectability condition. In addition to observability, the role of controllability in filter stability is explored. Finally, the results are partially extended to non-compact signal state spaces

Development and implementation of an herbal and natural product elective in undergraduate medical education

<p>Abstract</p> <p>Background</p> <p>Medical students have consistently expressed interest in learning about alternative healing modalities, especially herbal and natural products. To fill this void in medical education at our institution, a novel elective was developed and implemented for fourth year medical students. This herbal/natural product course uses guest lecturers, classroom presentations, and active learning mechanisms that include experiential rotations, case-based learning, and team-based learning to increase student knowledge of herbal/natural product safety and efficacy.</p> <p>Methods</p> <p>Knowledge outcomes were evaluated via administration of a pre- and post-course test (paired student <it>t</it>-test). End-of-course evaluations (Likert-type questions and narrative responses) were used to assess student opinion of knowledge and skills imparted by the elective and overall course content (mean, standard deviation).</p> <p>Results</p> <p>Over three academic years, 23 students have enrolled in this elective. More than 60% of participants have been female and nearly half of the students (43%) have pursued residencies in primary care. Completion of the course significantly increased student knowledge of common herbal/natural product mechanisms, uses, adverse effects, and drug-interactions as determined by a pre- and post-course knowledge assessment (45% ± 10% versus 78% ± 6%; p < 0.0001). The course was highly rated by enrollees (overall course quality, 4.6 of 5.0 ± 0.48) who appreciated the variety of activities to which they were exposed and the open classroom discussions that resulted. While students tended to view some alternative medical systems with skepticism, they still believed it was valuable to learn what these modalities encompass.</p> <p>Conclusions</p> <p>Development and implementation of a herbal/natural product elective that engages undergraduate medical students through active learning mechanisms and critical analysis of the literature has proven effective in increasing knowledge outcomes and is deemed to be a valuable curricular addition by student participants. In the future, it will be of interest to explore mechanisms for expanding the course to reach a larger number of students within the time, financial, and logistical constraints that currently exist.</p

Antideuterons as a Signature of Supersymmetric Dark Matter

Once the energy spectrum of the secondary component is well understood, measurements of the antiproton cosmic-ray flux at the Earth will be a powerful way to indirectly probe for the existence of supersymmetric relics in the galactic halo. Unfortunately, it is still spoilt by considerable theoretical uncertainties. As shown in this work, searches for low-energy antideuterons appear in the mean time as a plausible alternative, worth being explored. Above a few GeV/n, a dozen spallation antideuterons should be collected by the future AMS experiment on board ISSA. For energies less than about 3 GeV/n, the antideuteron spallation component becomes negligible and may be supplanted by a potential supersymmetric signal. If a few low-energy antideuterons are discovered, this should be seriously taken as a clue for the existence of massive neutralinos in the Milky Way.Comment: 16 pages, 9 figure