Dynamic Modeling of Metal Columns with Open Thin-Walled Sections

High-height columns become more economically viable when designed with thin-walled open cross-sections. For such structural release, there is the occurrence of the flexion-torsion phenomenon and the evident loss of lateral stiffness, which can be reduced with the presence of bracing by lintels spaced at height. In the case of road bridges and overhead cranes, there is a low traffic speed, characterizing internal forces that allow the use of cross-sections folded into C and Z-shaped sheet metal, as well as double-T-shaped welded metal sections. In this sense, this paper is intended to contribute to the advancement of the Continuous Medium Technique (CMT) formulation through the Wall Panel Theory (WPT) applied to the thin-walled columns. Through the WPT applied to thin-walled sections, it is possible to express the system of differential equations of the static problem, characterizing the rigidity of the core column via matrix [J] and bracing by matrix [S]. In item 2.3, the inclusion of the dynamic portion in the WPT is performed, thus providing the determination and characterization of the first seven vibration modes of the abovementioned column. Finally, this paper provides the structural engineer with a manual verification tool (via CMT) of static or dynamic modeling for thin-walled columns using commercial software. In this paper we used software ANSYS 2019 R1 (student version) for such numerical checks and validations.

     

Functional characteristics and radiation tolerance of AToM, thefront-end chip of BaBar silicon vertex tracker

The readout chip designed to process the microstrip signals in the BaBar Silicon Vertex Tracker (SVT), after being realized twice in a radsoft technology has been transferred into the final radhard process. So far the circuit has gone through four different radhard submissions, one aiming at providing a preliminary insight into the characteristics of the radhard chip, the other ones constituting pre-production and production runs. Chips from these submissions have undergone a thorough set of tests addressing functional aspects, noise parameters and effects of radiation on signal and noise behavior. The present paper discusses the results of these tests and describes the final version of the circuit which has been proven to successfully meet the experiment requirements     

A meshless FPM model for solving nonlinear material problems with proportional loading based on deformation theory

In this work a methodology of meshless finite points method for the analysis of nonlinear material problems with proportional loading based on deformation theory is presented.In finite points method the approximation around each point is obtained by using weighted least square techniques. The discrete system of equation is constructed by means of a point collocation procedure. The non-dependence on a mesh or integration procedures is an important aspect which transforms the finite point method in a truly meshless technique.Hencky’s total deformation theory and an elastic approach is used on the determination of stress–strain fields. This approach introduces the concept of effective material properties which are considered as spatial field variables and to be functions of equilibrium stress state and material properties.The present results are in good agreement with those obtained by nonlinear finite element method and previous work in this meshless context. Nevertheless the present methodology is based on a strong formulation, keeping the meshless characteristics of FPM.     

Associative Memories in Infinite Dimensional Spaces

A generalization of the Little–Hopfield neural network model for associative memories is presented that considers the case of a continuum of processing units. The state space corresponds to an infinite dimensional euclidean space. A dynamics is proposed that minimizes an energy functional that is a natural extension of the discrete case. The case in which the synaptic weight operator is defined through the autocorrelation rule (Hebb rule) with orthogonal memories is analyzed. We also consider the case of memories that are not orthogonal. Finally, we discuss the generalization of the non deterministic, finite temperature dynamics.     

Understanding and characterizing nestedness in mutualistic bipartite networks

In this work we present a dynamical model that successfully describes the organization of mutualistic ecological systems. The main characteristic of these systems is the nested structure of the bipartite adjacency matrix describing their interactions. We introduce a nestedness coefficient, as an alternative to the Atmar and Patterson temperature, commonly used to measure the nestedness degree of the network. This coefficient has the advantage of being based on the robustness of the ecological system and it is not only describing the ordering of the bipartite matrix but it is also able to tell the difference, if any, between the degree of organization of each guild.     

Lipid changes in hepatic microsomes and its relationship to P-nitrophenol glucuronidation in an experimental model of portal hypertension

The liver is responsible for the most important metabolic pathway of non polar compounds. The aim of the present work was to study the p-nitrophenol glucuronidation and its relationship with lipidic composition of microsomal membrane in a model of hepatic portal hypertension and hepatocellular damage induced by monocrotaline. A global increment in liver microsomal phospholipids as well as changes in the phospholipid pattern (phosphatidylethanolamine and sphingomyelin increased up to 156 +/- 13 and 195 +/- 14% respectively) were detected in monocrotaline intoxicated rats when it were compared to control rats. The microsomal cholesterol content showed a decrease in monocrotaline intoxicated rats. (4.1 +/- 0.7 against 6.6 +/- 1.5 micrograms/mg of microsomal protein, in control rats). When p-nitrophenol activity was measured, Km from monocrotaline intoxicated rats was 0.137 mM, and Vmax was 2.9 nmol of p-nitrophenol/mg microsomal protein since in control group Km was 0.322 mM, and Vmax was 4.5 nmol of p-nitrophenol/mg microsomal protein. It is concluded that monocrotaline intoxicated rats showed a different behavior in the kinetics of p-nitrophenol UDP-glucuronyltransferase, as well as a different microsomal lipidic profile, when compared to control group.     

Biologically Plausible Associative Memory: Continuous Unit Response + Stochastic Dynamics

A neural network model of associative memory is presented which unifies the two historically more relevant enhancements to the basic Little-Hopfield discrete model: the graded response units approach and the stochastic, Glauber-inspired model with a random field representing thermal fluctuations. This is done by casting the retrieval process of the model with graded response neurons, into the framework of a diffusive process governed by the Fokker-Plank equation, which leads to a Langevin system describing the process at a microscopic level, while the time evolution of the probability density function is governed by a multivariate Fokker Planck equation operating over the space of all possible activation patterns. The present unified approach has two notable features: (i) greater biological plausibility and (ii) ability to escape local minima of energy (associated with spurious memories), which makes it a potential tool for those complex optimization problems for which the previous models failed.     

From self-organized criticality to first-order-like behavior: A new type of percolative transition

The number of silver stained nucleolar organiser regions (Ag-NORs) was enumerated in the biopsy specimens of 73 patients with human pancreatic adenocarcinoma. The number of Ag-NORs was related to histological features, S-phase fraction (SPF), DNA ploidy, morphometric nuclear features, clinical stage and survival. Grade I tumours had on average fewer Ag-NORs (mean +/- SD, 5.2 +/- 2.0) than grade II (mean +/- SD, 5.9 +/- 1.6) or grade III (mean +/- SD, 6.6 +/- 2.6) tumours. Patients with low SPF (0-7%) values had lower mean Ag-NORs counts (5.7 +/- 1.0) than patients with a high SPF (7%) (6.6 +/- 2.0) (p = 0.05) and the number of Ag-NORs was related almost significantly to mitotic index (p = 0.09). The Ag-NORs were not related significantly to DNA ploidy or to clinical stage. In survival analysis the number of Ag-NORs predicted prognosis significantly (p = 0.03). From the results we conclude that Ag-NORs are related to several malignant features in human pancreatic adenocarcinoma and that the number of Ag-NORs predicts survival.     

Urinary biomarkers of kidney diseases in HIV-infected children

A significant number of children infected with the human immunodeficiency virus 1 (HIV-1) virus all over the world are at risk of developing renal diseases that could have a significant impact on their treatment and quality of life. It is necessary to identify children undergoing the early stages of these renal diseases, as well as the potential renal toxicity that could be caused by antiretroviral drugs, in order to prevent the development of cardiovascular complications and chronic renal failure. This article describes the most common renal diseases seen in HIV-infected children, as well as the value and limitations of the clinical markers that are currently being used to monitor their renal function and histological damage in a noninvasive manner. In addition, we discuss the progress made during the last 10 years in the discovery and validation of new renal biomarkers for HIV-infected children and young adults. Although significant progress has been made during the early phases of the biomarkers discovery, more work remains to be done to validate the new biomarkers in a large number of patients. The future looks promising, however, the new knowledge needs to be integrated and validated in the context of the clinical environment where these children are living.