Fractional Calculus: Historical Notes Apuntes Históricos del Cálculo Fraccionario

En este trabajo, presentamos algunos apuntes históricos del cálculo fraccionario Local, y destacamos algunas propiedades y aplicaciones de estas nuevas herramientas matemicasIn this paper, we present some historical notes to Generalized Calculus, sometimes called Local Fractional Calculus, and highlight some properties and applications of these new mathematical tool

Modeling of a Cable-Based Revolute Joint Using Biphasic Media Variable Stiffness Actuation

In recent times, safe interactions between humans and robots are required for innumerable tasks and environments. This safety can be achieved using compliance design and control of mechanisms. Cable-driven mechanisms are used when applications need to have light structures, meaning that their actuators must be relocated to ground and forces are transferred along tensioned cables. This paper presents a compliant cable-driven revolute joint using biphasic media variable stiffness actuators. Actuator's stiffness is controlled by changing pressure of control fluid into distribution lines. The used control fluid is biphasic, composed of separated gas and liquid fractions with predefined ratio. The mathematical model of the actuator is presented along with its position and stiffness model-based control, then, equations relating to the dynamics of the mechanism are provided with a joint stiffness and orientation controller. Results from simulations are discussed

Bosonic Field Propagators on Algebraic Curves

In this paper we investigate massless scalar field theory on non-degenerate algebraic curves. The propagator is written in terms of the parameters appearing in the polynomial defining the curve. This provides an alternative to the language of theta functions. The main result is a derivation of the third kind differential normalized in such a way that its periods around the homology cycles are purely imaginary. All the physical correlation functions of the scalar fields can be expressed in terms of this object. This paper contains a detailed analysis of the techniques necessary to study field theories on algebraic curves. A simple expression of the scalar field propagator is found in a particular case in which the algebraic curves have $Z_n$ internal symmetry and one of the fields is located at a branch point.Comment: 26 pages, TeX + harvma

Transfer Hydrogenation of Azo Compounds with Ammonia Borane Using a Simple Acyclic Phosphite Precatalyst

Tris(quinolin-8-yl)phosphite, P(Oquin)(3), promotes the dehydrogenation of H3N center dot BH3 (AB) and the transfer hydrogenation of azoarenes using ammonia borane (AB) as H-2 source. The metal-free reduction of azoarenes proceeds under mild reaction conditions upon which several diphenylhydrazine derivatives are obtained in high yields. The reactivity of P(Oquin)(3) toward AB was evaluated through NMR in situ tests. The rate of the reaction, activation parameters, deuterium kinetic isotope effect (DKIE) and linear-free energy relationship were investigated. Such mechanistic and kinetic studies suggest that P(Oquin)(3) is a precatalyst and that AB is likely involved in more than one stage of the reaction pathway. Furthermore, the kinetic data indicate that the reaction proceeds through an ordered transition state, possibly associative

Low temperature exposure induces browning of bone marrow stem cell derived adipocytes in vitro

Brown and beige adipocytes are characterised as expressing the unique mitochondrial uncoupling protein (UCP)1 for which the primary stimulus in vivo is cold exposure. The extent to which cold-induced UCP1 activation can also be achieved in vitro, and therefore perform a comparable cellular function, is unknown. We report an in vitro model to induce adipocyte browning using bone marrow (BM) derived mesenchymal stem cells (MSC), which relies on differentiation at 32 °C instead of 37 °C. The low temperature promoted browning in adipogenic cultures, with increased adipocyte differentiation and upregulation of adipogenic and thermogenic factors, especially UCP1. Cells exhibited enhanced uncoupled respiration and metabolic adaptation. Cold-exposed differentiated cells showed a marked translocation of leptin to adipocyte nuclei, suggesting a previously unknown role for leptin in the browning process. These results indicate that BM-MSC can be driven to forming beige-like adipocytes in vitro by exposure to a reduced temperature. This in vitro model will provide a powerful tool to elucidate the precise role of leptin and related hormones in hitherto functions in the browning process

Monopoles and Holography

We present a holographic theory in AdS_4 whose zero temperature ground state develops a crystal structure, spontaneously breaking translational symmetry. The crystal is induced by a background magnetic field, but requires no chemical potential. This lattice arises from the existence of 't Hooft-Polyakov monopole solitons in the bulk which condense to form a classical object known as a monopole wall. In the infra-red, the magnetic field is screened and there is an emergent SU(2) global symmetry.Comment: 33 pages, 16 figures; v2: ref adde

Loneliness and Frailty Among Middle-Aged and Aging Sexual Minority Men Living With or Without HIV: A Longitudinal Cross-Lagged Panel Analysis

Background and Objectives Loneliness is associated with frailty among older adults (60+), and there is evidence suggesting that this association may be bidirectional. However, there is limited evidence of this relationship over time among middle-aged and aging sexual minority men. We explored the bidirectional relationship between loneliness and frailty over 2 years among sexual minority men living with or without human immunodeficiency virus (HIV) from the Healthy Aging substudy of the Multicenter AIDS Cohort Study. Research Design and Methods We used data from 1 118 men (561 living with HIV; 557 living without HIV) aged 40 years or older with measurement of frailty or loneliness at Times 1 (September 2016 to March 2017) and 2 (September 2018 to March 2019). Descriptive statistics were generated. We used autoregressive cross-lagged panel analysis to examine the bidirectional association between frailty and loneliness at both time points while adjusting for time-stable and time-dependent covariates at Time 1. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were generated. Results The estimated prevalence of loneliness at both time points was 35.5%. The estimated prevalence of frailty at Times 1 and 2 were 7.8% and 12.1%, respectively. Participants reporting loneliness at Time 1 had greater odds of being frail at Time 2 (aOR = 2.14; 95% CI: 1.23–3.73). Frailty at Time 1 was not associated with loneliness at Time 2 (aOR = 1.00; 95% CI: .44–2.25). The autoregressive effects of frailty (aOR = 23.43; 95% CI: 11.94–46) and loneliness (aOR = 13.94; 95% CI: 9.42–20.61) were large. Discussion and Implications Men who felt lonely had higher odds of being frail 2 years later while the reciprocal association was not shown. This suggests that loneliness preceded frailty and not the other way around. Early and frequent assessments of loneliness may present opportunities for interventions that minimize the risk of frailty among sexual minority men living with and without HIV.This was supported by the National Institute on Minority Health and Health Disparities (grant number R01 MD010680; M.R.F. and M.P.) and the National Institute on Drug Abuse (grant number K01DA047912). The contents of this publication are solely the responsibility of the authors and do not represent the official views of the National Institutes of Health (NIH). MACS/WIHS Combined Cohort Study (MWCCS) (Principal Investigators): Atlanta Clinical Research Site (CRS) (Ighovwerha Ofotokun, Anandi Sheth, and Gina Wingood), U01-HL146241; Baltimore CRS (Todd Brown and Joseph Margolick), U01-HL146201; Bronx CRS (Kathryn Anastos and Anjali Sharma), U01-HL146204; Brooklyn CRS (Deborah Gustafson and Tracey Wilson), U01-HL146202; Data Analysis and Coordination Center (Gypsyamber D’Souza, Stephen Gange, and Elizabeth Golub), U01-HL146193; Chicago–Cook County CRS (Mardge Cohen and Audrey French), U01-HL146245; Chicago-Northwestern CRS (Steven Wolinsky), U01-HL146240; Connie Wofsy Women’s HIV Study, Northern California CRS (Bradley Aouizerat, Phyllis Tien, and Jennifer Price), U01-HL146242; Los Angeles CRS (Roger Detels), U01-HL146333; Metropolitan Washington CRS (Seble Kassaye and Daniel Merenstein), U01-HL146205; Miami CRS (Maria Alcaide, Margaret Fischl, and Deborah Jones), U01-HL146203; Pittsburgh CRS (Jeremy Martinson and Charles Rinaldo), U01-HL146208; UAB-MS CRS (Mirjam-Colette Kempf, Jodie Dionne-Odom, and Deborah Konkle-Parker), U01-HL146192; and UNC CRS (Adaora Adimora), U01-HL146194. The MWCCS is funded primarily by the National Heart, Lung, and Blood Institute, with additional co-funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute on Aging, National Institute of Dental and Craniofacial Research, National Institute of Allergy and Infectious Diseases, National Institute of Neurological Disorders and Stroke, National Institute of Mental Health, National Institute on Drug Abuse, National Institute of Nursing Research, National Cancer Institute, National Institute on Alcohol Abuse and Alcoholism, National Institute on Deafness and Other Communication Disorders, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute on Minority Health and Health Disparities, and in coordination and alignment with the research priorities of the NIH, Office of AIDS Research. MWCCS data collection is also supported by UL1-TR000004 (University of California, San Francisco Clinical and Translational Science Award), P30-AI-050409 (Atlanta Center for AIDS Research [CFAR]), P30-AI-050410 (UNC CFAR), and P30-AI-027767 (University of Alabama CFAR). This work was also supported by national funds through the FCT–Foundation for Science and Technology, I.P., within the scope of projects UIDB/04750/2020 and LA/P/0064/2020. This study was also supported by a Scientific Employment Stimulus contract to A.H. (CEECIND/01793/2017)

Analysis of a spatial Lotka-Volterra model with a finite range predator-prey interaction

We perform an analysis of a recent spatial version of the classical Lotka-Volterra model, where a finite scale controls individuals' interaction. We study the behavior of the predator-prey dynamics in physical spaces higher than one, showing how spatial patterns can emerge for some values of the interaction range and of the diffusion parameter.Comment: 7 pages, 7 figure

Dose-response relationship between cigarette smoking and site-specific cancer risk : protocol for a systematic review with an original design combining umbrella and traditional reviews

Introduction Only a limited number of meta-analyses providing risk curve functions of dose-response relationships between various smoking-related variables and cancer-specific risk are available. Methods and analysis To identify all relevant original publications on the issue, we will conduct a series of comprehensive systematic reviews based on three subsequent literature searches: (1) an umbrella review, to identify meta-analyses, pooled analyses and systematic reviews published before 28 April 2017 on the association between cigarette smoking and the risk of 28 (namely all) malignant neoplasms; (2) for each cancer site, an updated review of original publications on the association between cigarette smoking and cancer risk, starting from the last available comprehensive review identified through the umbrella review; and (3) a review of all original articles on the association between cigarette smoking and site-specific cancer risk included in the publications identified through the umbrella review and the updated reviews. The primary outcomes of interest will be (1) the excess incidence/mortality of various cancers for smokers compared with never smokers; and (2) the dose-response curves describing the association between smoking intensity, duration and time since stopping and incidence/mortality for various cancers. For each cancer site, we will perform a meta-analysis by pooling study-specific estimates for smoking status. We will also estimate the dose-response curves for other smoking-related variables through random-effects meta-regression models based on a non-linear dose-response relationship framework. Ethics and dissemination Ethics approval is not required for this study. Main results will be published in peer-reviewed journals and will also be included in a publicly available website. We will provide therefore the most complete and updated estimates on the association between various measures of cigarette smoking and site-specific cancer risk. This will allow us to obtain precise estimates on the cancer burden attributable to cigarette smoking. Trial registration number This protocol was registered in the International Prospective Register of Systematic Reviews (CRD42017063991)