Los elementos, las partes y el todo Reflexión sobre el papel de la “parte” en la composición formal de la arquitectura

La arquitectura se compone de una serie de elementos y son invariablemente los mismos desde sus orígenes: puertas, ventanas, columnas, muros, escaleras, cubiertas y pisos. Si bien el número es limitado, cada elemento constituye en sí mismo un mundo de variaciones y al agruparse, puede conformar partes de una totalidad o la totalidad misma: la forma arquitectónica. Veremos como la existencia o no existencia de una escala intermedia o mediadora entre los elementos y la totalidad –la parte–, determina en modo considerable el resultado final al interior del objeto arquitectónico

Role of astrocytes in manganese mediated neurotoxicity

Astrocytes are responsible for numerous aspects of metabolic support, nutrition, control of the ion and neurotransmitter environment in central nervous system (CNS). Failure by astrocytes to support essential neuronal metabolic requirements plays a fundamental role in the pathogenesis of brain injury and the ensuing neuronal death. Astrocyte-neuron interactions play a central role in brain homeostasis, in particular via neurotransmitter recycling functions. Disruption of the glutamine (Gln)/glutamate (Glu) -γ-aminobutyric acid (GABA) cycle (GGC) between astrocytes and neurons contributes to changes in Glu-ergic and/or GABA-ergic transmission, and is associated with several neuropathological conditions, including manganese (Mn) toxicity. In this review, we discuss recent advances in support of the important roles for astrocytes in normal as well as neuropathological conditions primarily those caused by exposure to Mn

The MST of symmetric disk graphs is light

AbstractSymmetric disk graphs are often used to model wireless communication networks. Given a set S of n points in Rd (representing n transceivers) and a transmission range assignment r:S→R, the symmetric disk graph of S (denoted SDG(S)) is the undirected graph over S whose set of edges is E={(u,v)|r(u)⩾|uv| and r(v)⩾|uv|}, where |uv| denotes the Euclidean distance between points u and v. We prove that the weight of the MST of any connected symmetric disk graph over a set S of n points in the plane, is only O(logn) times the weight of the MST of the complete Euclidean graph over S. We then show that this bound is tight, even for points on a line.Next, we prove that if the number of different ranges assigned to the points of S is only k, k≪n, then the weight of the MST of SDG(S) is at most 2k times the weight of the MST of the complete Euclidean graph. Moreover, in this case, the MST of SDG(S) can be computed efficiently in time O(knlogn).We also present two applications of our main theorem, including an alternative proof of the Gap Theorem, and a result concerning range assignment in wireless networks.Finally, we show that in the non-symmetric model (where E={(u,v)|r(u)⩾|uv|}), the weight of a minimum spanning subgraph might be as big as Ω(n) times the weight of the MST of the complete Euclidean graph

Bounded-Angle Spanning Tree: Modeling Networks with Angular Constraints

We introduce a new structure for a set of points in the plane and an angle $\alpha$, which is similar in flavor to a bounded-degree MST. We name this structure $\alpha$-MST. Let $P$ be a set of points in the plane and let $0 < \alpha \le 2\pi$ be an angle. An $\alpha$-ST of $P$ is a spanning tree of the complete Euclidean graph induced by $P$, with the additional property that for each point $p \in P$, the smallest angle around $p$ containing all the edges adjacent to $p$ is at most $\alpha$. An $\alpha$-MST of $P$ is then an $\alpha$-ST of $P$ of minimum weight. For $\alpha < \pi/3$, an $\alpha$-ST does not always exist, and, for $\alpha \ge \pi/3$, it always exists. In this paper, we study the problem of computing an $\alpha$-MST for several common values of $\alpha$. Motivated by wireless networks, we formulate the problem in terms of directional antennas. With each point $p \in P$, we associate a wedge $W_p$ of angle $\alpha$ and apex $p$. The goal is to assign an orientation and a radius $r_p$ to each wedge $W_p$, such that the resulting graph is connected and its MST is an $\alpha$-MST. (We draw an edge between $p$ and $q$ if $p \in W_q$, $q \in W_p$, and $|pq| \le r_p, r_q$.) Unsurprisingly, the problem of computing an $\alpha$-MST is NP-hard, at least for $\alpha=\pi$ and $\alpha=2\pi/3$. We present constant-factor approximation algorithms for $\alpha = \pi/2, 2\pi/3, \pi$. One of our major results is a surprising theorem for $\alpha = 2\pi/3$, which, besides being interesting from a geometric point of view, has important applications. For example, the theorem guarantees that given any set $P$ of $3n$ points in the plane and any partitioning of the points into $n$ triplets, one can orient the wedges of each triplet {\em independently}, such that the graph induced by $P$ is connected. We apply the theorem to the {\em antenna conversion} problem

Multifaceted Determinants for Achieving Glycemic Control the International Diabetes Management Practice Study (IDMPS)

OBJECTIVE - the International Diabetes Mellitus Practice Study is a 5-year survey documenting changes in diabetes treatment practice in developing regions.RESEARCH DESIGN and METHODS - Logistic regression analysis was used to identify factors for achieving A1C <7% in 11,799 patients (1,898 type 1 diabetic and 9,901 type 2 diabetic) recruited by 937 physicians from 1.7 countries in Eastern Europe (n = 3,519), Asia (n = 5,888), Latin America (n = 2,116), and Africa (n = 276).RESULTS - Twenty-two percent of type 1 diabetic and 36% of type 2 diabetic patients never had A1C measurements. in those with values for A1C, blood pressure, and LDL cholesterol, 7.5% of type 1 diabetic (n = 696) and 3.6% of type 2 diabetic (n = 3,896) patients attained all three recommended targets (blood pressure <130/80 mmHg, LDL cholesterol <100 mg/dl, and A1C <7%). Self-monitoring of blood glucose was the only predictor for achieving the A1C goal in type 1 diabetes (odds ratios: Asia 2.24, Latin America 3.55, and Eastern Europe 2.42). in type 2 diabetes, short disease duration (Asia 0.97, Latin America 0.97, and Eastern Europe 0.82) and treatment With few oral glucose-lowering drugs (Asia 0,64, Latin America 0.76, and Eastern Europe 0,62) were predictors, Other region-specific factors included lack of microvascular complications and old age in Latin America and Asia; health insurance coverage and specialist care in Latin America; lack of obesity and self-adjustment of insulin dosages in Asia; and training by a diabetes educator, self-monitoring of blood glucose in Patients who self-adjusted insulin, and lack of macrovascular complications in Eastern Europe.CONCLUSIONS - in developing countries, factors pertinent to Patients, doctors, and health care systems all impact on glycemic control.Chinese Univ Hong Kong, Prince Wales Hosp, Dept Med & Therapeut, Hong Kong, Hong Kong, Peoples R ChinaNatl Univ La Plata, Sch Med,Ctr Expt & Appl Endocrinol, Collaborating Ctr Diabet,Natl Sci & Tech Res Coun, WHO,Pan Amer Hlth Org, La Plata, Buenos Aires, ArgentinaKorea Univ, Guro Hosp, Dept Internal Med, Seoul, South KoreaDept Intercontinental Med Affairs, Paris, FranceUniversidade Federal de São Paulo, Dept Prevent Med, São Paulo, BrazilIuliu Hatieganu Univ Med, Diabet Ctr & Clin, Cluj Napoca, RomaniaIstanbul Univ, Cerrahpasa Med Fac, Dept Internal Med, Istanbul, TurkeyDr A Ramachandrans Diabet Hosp, India Diabet Res Fdn, Madras, Tamil Nadu, IndiaJaveriana Univ, Endocrinol Unit, Bogota, ColombiaUniversidade Federal de São Paulo, Dept Prevent Med, São Paulo, BrazilWeb of Scienc

Canagliflozin for the treatment of adults with Type 2 diabetes

AdultosCanagliflozin is a competitive, reversible and potent inhibitor of SGLT2 that lowers the renal threshold for glucose and consequently increases urinary glucose excretion in people with Type 2 diabetes with a blood glucose level above 70–90 mg/dl. Its oral administration in daily doses of 100 and 300 mg in onotherapy, dual therapy or triple therapy including insulin produces a mean HbA1c reduction of 0.7 and 0.85%, respectively, when compared with placebo, a similar reduction to sitagliptin and glimepiride. There is also a modest reduction in weight with both doses. The main adverse effects are genital fungal infections, particularly in women, and, less frequently, urinary tract infections.https://orcid.org/0000-0002-6860-3620N/

Association of exposure to manganese and iron with striatal and thalamic GABA and other neurometabolites - Neuroimaging results from the WELDOX II study

OBJECTIVE: Magnetic resonance spectroscopy (MRS) is a non-invasive method to quantify neurometabolite concentrations in the brain. Within the framework of the WELDOX II study, we investigated the association of exposure to manganese (Mn) and iron (Fe) with γ-aminobutyric acid (GABA) and other neurometabolites in the striatum and thalamus of 154 men. MATERIAL AND METHODS: GABA-edited and short echo-time MRS at 3T was used to assess brain levels of GABA, glutamate, total creatine (tCr) and other neurometabolites. Volumes of interest (VOIs) were placed into the striatum and thalamus of both hemispheres of 47 active welders, 20 former welders, 36 men with Parkinson's disease (PD), 12 men with hemochromatosis (HC), and 39 male controls. Linear mixed models were used to estimate the influence of Mn and Fe exposure on neurometabolites while simultaneously adjusting for cerebrospinal fluid (CSF) content, age and other factors. Exposure to Mn and Fe was assessed by study group, blood concentrations, relaxation rates R1 and R2* in the globus pallidus (GP), and airborne exposure (active welders only). RESULTS: The median shift exposure to respirable Mn and Fe in active welders was 23μg/m3 and 110μg/m3, respectively. Airborne exposure was not associated with any other neurometabolite concentration. Mn in blood and serum ferritin were highest in active and former welders. GABA concentrations were not associated with any measure of exposure to Mn or Fe. In comparison to controls, tCr in these VOIs was lower in welders and patients with PD or HC. Serum concentrations of ferritin and Fe were associated with N-acetylaspartate, but in opposed directions. Higher R1 values in the GP correlated with lower neurometabolite concentrations, in particular tCr (exp(β)=0.87, p<0.01) and choline (exp(β)=0.84, p=0.04). R2* was positively associated with glutamate-glutamine and negatively with myo-inositol. CONCLUSIONS: Our results do not provide evidence that striatal and thalamic GABA differ between Mn-exposed workers, PD or HC patients, and controls. This may be due to the low exposure levels of the Mn-exposed workers and the challenges to detect small changes in GABA. Whereas Mn in blood was not associated with any neurometabolite content in these VOIs, a higher metal accumulation in the GP assessed with R1 correlated with generally lower neurometabolite concentrations