Statistical mixing and aggregation in Feller diffusion

We consider Feller mean-reverting square-root diffusion, which has been applied to model a wide variety of processes with linearly state-dependent diffusion, such as stochastic volatility and interest rates in finance, and neuronal and populations dynamics in natural sciences. We focus on the statistical mixing (or superstatistical) process in which the parameter related to the mean value can fluctuate - a plausible mechanism for the emergence of heavy-tailed distributions. We obtain analytical results for the associated probability density function (both stationary and time dependent), its correlation structure and aggregation properties. Our results are applied to explain the statistics of stock traded volume at different aggregation scales.Comment: 16 pages, 3 figures. To be published in Journal of Statistical Mechanics: Theory and Experimen

Bipolar HII regions - Morphology and star formation in their vicinity - I - G319.88++00.79 and G010.32−-00.15

Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII regions. We search for their exciting star(s) and estimate their distances using near-IR data. Dense clumps are detected using Herschel-SPIRE data. MALT90 observations allow us to ascertain their association with the central HII region. We identify Class 0/I YSOs using their Spitzer and Herschel-PACS emissions. These methods will be applied to the entire sample of candidate bipolar HII regions. This paper focuses on two bipolar HII regions, one interesting in terms of its morphology, G319.88$+$00.79, and one in terms of its star formation, G010.32$-$00.15. Their exciting clusters are identified and their photometric distances estimated to be 2.6 kpc and 1.75 kpc, respectively. We suggest that these regions formed in dense and flat structures that contain filaments. They have a central ionized region and ionized lobes perpendicular to the parental cloud. The remains of the parental cloud appear as dense (more than 10^4 per cm^3) and cold (14-17 K) condensations. The dust in the PDR is warm (19-25 K). Dense massive clumps are present around the central ionized region. G010.32-00.14 is especially remarkable because five clumps of several hundred solar masses surround the central HII region; their peak column density is a few 10^23 per cm^2, and the mean density in their central regions reaches several 10^5 per cm^3. Four of them contain at least one massive YSO; these clumps also contain extended green objects and Class II methanol masers. This morphology suggests that the formation of a second generation of massive stars has been triggered by the central bipolar HII region. It occurs in the compressed material of the parental cloud.Comment: 32 pages, 28 figures, to be published in A&

Levantamento sobre genótipos de mandioca utilizados pelos agricultores de pequena escala, na baixada cuiabana, MT

Foi realizado um levantamento sobre os genótipos de mandioca utilizados pelos agricultores na Baixada Cuiabana, região que compreende 14 municípios entorno de Cuiabá, composto de muitos agricultores tradicionais. O MT é um dos centros de origem e diversificação da Manihot esculenta, sendo essa região detentora de uma grande tradição de produção de farinha, devido ao alto consumo pela sua culinária regional. A agricultura familiar desempenha papel fundamental na diversidade de plantas, representando uma forma importante de conservação in situ. Foi aplicado um questionário para os técnicos da EMPAER (Empresa Extensão Rural do Mato Grosso) que atuam na região para identificar os genótipos de mandioca de mesa e de indústria. Foram citados 11, todos eles crioulos os quais foram: ?Igarapé Vermelha?, ?Liberata?, ?Sopão?, ?Juriti?, ?Broto branco?, ?Mansa?, ?Broto roxo?, ?Cacau?, ?Uva?, ?Galhadeira? e ?Olho junto?. Não foram mencionados genótipos melhorados, como da Embrapa ou IAC. Os genótipos ?Liberata? e ?Juriti? foram citados tanto para consumo em mesa, como para indústria na fabricação de farinha, indicando dupla aptidão. Porém, ?Liberata? foi o mais mencionado, sendo citados por técnicos de todos os municípios. Os agricultores tradicionais dessa região são mantenedores da diversidade local

Agricultural practices and ecosystem services provision to ensure the food, water and energy security.

Considering the importance of the agricultural sector in Brazil and the existence of areas in different stages of degradation, it becomes strategic for interventions that can generate socio-economic and environmental benefits and positive impacts to the tripod F-W-E. Thus, the present study is based on the Ribeirão das Lajes dam (RJ), a core area for the water supply of the second largest city in Brazil - Rio de Janeiro. A methodological approach will be developed that will generate an integrated assessment tool to evaluate the impact of agriculture practices and its potentiality to ecosystem services provision in the Nexus F-W-E approach

On stochastic sea of the standard map

Consider a generic one-parameter unfolding of a homoclinic tangency of an area preserving surface diffeomorphism. We show that for many parameters (residual subset in an open set approaching the critical value) the corresponding diffeomorphism has a transitive invariant set $\Omega$ of full Hausdorff dimension. The set $\Omega$ is a topological limit of hyperbolic sets and is accumulated by elliptic islands. As an application we prove that stochastic sea of the standard map has full Hausdorff dimension for sufficiently large topologically generic parameters.Comment: 36 pages, 5 figure

Sparsity and Incoherence in Compressive Sampling

We consider the problem of reconstructing a sparse signal $x^0\in\R^n$ from a limited number of linear measurements. Given $m$ randomly selected samples of $U x^0$, where $U$ is an orthonormal matrix, we show that $\ell_1$ minimization recovers $x^0$ exactly when the number of measurements exceeds $$m\geq \mathrm{Const}\cdot\mu^2(U)\cdot S\cdot\log n,$$ where $S$ is the number of nonzero components in $x^0$, and $\mu$ is the largest entry in $U$ properly normalized: $\mu(U) = \sqrt{n} \cdot \max_{k,j} |U_{k,j}|$. The smaller $\mu$, the fewer samples needed. The result holds for ``most'' sparse signals $x^0$ supported on a fixed (but arbitrary) set $T$. Given $T$, if the sign of $x^0$ for each nonzero entry on $T$ and the observed values of $Ux^0$ are drawn at random, the signal is recovered with overwhelming probability. Moreover, there is a sense in which this is nearly optimal since any method succeeding with the same probability would require just about this many samples

Telemedicine During COVID-19 and Beyond: A Practical Guide and Best Practices Multidisciplinary Approach for the Orthopedic and Neurologic Pain Physical Examination.

BACKGROUND:The COVID pandemic has impacted almost every aspect of human interaction, causing global changes in financial, health care, and social environments for the foreseeable future. More than 1.3 million of the 4 million cases of COVID-19 confirmed globally as of May 2020 have been identified in the United States, testing the capacity and resilience of our hospitals and health care workers. The impacts of the ongoing pandemic, caused by a novel strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have far-reaching implications for the future of our health care system and how we deliver routine care to patients. The adoption of social distancing during this pandemic has demonstrated efficacy in controlling the spread of this virus and has been the only proven means of infection control thus far. Social distancing has prompted hospital closures and the reduction of all non-COVID clinical visits, causing widespread financial despair to many outpatient centers. However, the need to treat patients for non-COVID problems remains important despite this pandemic, as care must continue to be delivered to patients despite their ability or desire to report to outpatient centers for their general care. Our national health care system has realized this need and has incentivized providers to adopt distance-based care in the form of telemedicine and video medicine visits. Many institutions have since incorporated these into their practices without financial penalty because of Medicare\u27s 1135 waiver, which currently reimburses telemedicine at the same rate as evaluation and management codes (E/M Codes). Although the financial burden has been alleviated by this policy, the practitioner remains accountable for providing proper assessment with this new modality of health care delivery. This is a challenge for most physicians, so our team of national experts has created a reference guide for musculoskeletal and neurologic examination selection to retrofit into the telemedicine experience. OBJECTIVES:To describe and illustrate musculoskeletal and neurologic examination techniques that can be used effectively in telemedicine. STUDY DESIGN:Consensus-based multispecialty guidelines. SETTING:Tertiary care center. METHODS:Literature review of the neck, shoulder, elbow, wrist, hand, lumbar, hip, and knee physical examinations were performed. A multidisciplinary team comprised of physical medicine and rehabilitation, orthopedics, rheumatology, neurology, and anesthesia experts evaluated each examination and provided consensus opinion to select the examinations most appropriate for telemedicine evaluation. The team also provided consensus opinion on how to modify some examinations to incorporate into a nonhealth care office setting. RESULTS:Sixty-nine examinations were selected by the consensus team. Household objects were identified that modified standard and validated examinations, which could facilitate the examinations.The consensus review team did not believe that the modified tests altered the validity of the standardized tests. LIMITATIONS:Examinations selected are not validated for telemedicine. Qualitative and quantitative analyses were not performed. CONCLUSIONS:The physical examination is an essential component for sound clinical judgment and patient care planning. The physical examinations described in this manuscript provide a comprehensive framework for the musculoskeletal and neurologic examination, which has been vetted by a committee of national experts for incorporation into the telemedicine evaluation

Some remarks on the geometry of the Standard Map

We define and compute hyperbolic coordinates and associated foliations which provide a new way to describe the geometry of the standard map. We also identify a uniformly hyperbolic region and a complementary 'critical' region containing a smooth curve of tangencies between certain canonical 'stable' foliations.Comment: 25 pages, 11 figure