Suspension feeding in the enigmatic Ediacaran organism Tribrachidium demonstrates complexity of Neoproterozoic ecosystems

The first diverse and morphologically complex macroscopic communities appear in the late Ediacaran period, 575 to 541 million years ago (Ma). The enigmatic organisms that make up these communities are thought to have formed simple ecosystems characterized by a narrow range of feeding modes, with most restricted to the passive absorption of organic particles (osmotrophy). We test between competing feeding models for the iconic Ediacaran organism Tribrachidium heraldicum using computational fluid dynamics. We show that the external morphology of Tribrachidium passively directs water flow toward the apex of the organism and generates low-velocity eddies above apical “pits.” These patterns of fluid flow are inconsistent with osmotrophy and instead support the interpretation of Tribrachidium as a passive suspension feeder. This finding provides the oldest empirical evidence for suspension feeding at 555 to 550 Ma, ~10 million years before the Cambrian explosion, and demonstrates that Ediacaran organisms formed more complex ecosystems in the latest Precambrian, involving a larger number of ecological guilds, than currently appreciated.</p

Numerical Solutions of ideal two-fluid equations very closed to the event horizon of Schwarzschild black hole

The 3+1 formalism of Thorne, Price and Macdonald has been used to derive the linear two-fluid equations describing transverse and longitudinal waves propagating in the two-fluid ideal collisionless plasmas surrounding a Schwarzschild black hole. The plasma is assumed to be falling in radial direction toward the event horizon. The relativistic two-fluid equations have been reformulate, in analogy with the special relativistic formulation as explained in an earlier paper, to take account of relativistic effects due to the event horizon. Here a WKB approximation is used to derive the local dispersion relation for these waves and solved numerically for the wave number k.Comment: 16 pages, 15 figures. arXiv admin note: text overlap with arXiv:0902.3766, arXiv:0807.459

Validation of the Schizophrenia Quality of Life Scale Revision 4 among Chronic Schizophrenia Patients in Malaysia

Objectives: To explore the validity and reliability of a disease-specific health-related quality-of-life questionnaire-the Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4)-in patients with schizophrenia in Malaysia. Methods:A total of 222 outpatients with schizophrenia receiving treatment at the Universiti Kebangsaan Malaysia Medical Centre completed the SQLS-R4 in either the Malay or the English language. A generic self-report health-related quality-of-life measure-the EuroQoL group EuroQol five-dimensional questionnaire-and a measure of symptom severity-the Clinical Global Impression-Schizophrenia scale-were also administered to assess validity. Results: Good internal consistency reliability was found for both the psychosocial and vitality domains (Cronbach's ? = 0.95 and 0.85, respectively). Most items were also significantly correlated with their own scale score (r s ranging from 0.29 to 0.74). There was a moderate correlation between the SQLS-R4 "vitality" domain and the EuroQol five-dimensional questionnaire "usual activities" domain (r s = 0.44) and a large correlation between the SQLS-R4 "psychosocial" domain and the EuroQol five-dimensional questionnaire "anxiety/depression" domain (r s = 0.44-0.57). Most of the symptom dimensions of the Clinical Global Impression-Schizophrenia scale were also moderately correlated with the SQLS-R4 subscale scores. Conclusions:The SQLS-R4 is a valid and reliable health-related quality-of-life instrument for use in minimally ill patients with schizophrenia in Malaysia, but some of the items may be redundant and irrelevant. Validation of SQLS-R4 in different types of patients and various levels of illness severity is required to further verify its application.Scopu

Гендерная парадигма в образовании: от теории к практике

Computational fluid dynamics (CFD) simulations of water flow were performed in COMSOL. A model of Parvancorina sagitta from Russia with relief increased by 15% was oriented at 0° to the current and was fixed to the lower surface of a half-cylinder. Three-dimensional, incompressible flow of water was simulated with a normal inflow velocity inlet at the upstream end of the half-cylinder and a zero-pressure outlet at the downstream end. Slip boundary conditions were assigned to the top and sides of the half-cylinder, and no-slip boundary conditions were assigned to the Parvancorina model and the lower surface of the half-cylinder. The domain was meshed using free tetrahedral elements and the shear stress transport turbulence model was used to solve the Reynolds-averaged Navier–Stokes equations. A stationary solver was used to compute the steady-state flow patterns. Simulations were performed with an inlet velocity of 0.1, 0.2, and 0.5 m/s

Finite Element Simulation on Crack Analysis of a Thick-Tube

Most engineering failure began with cracks. Crack may caused by material defect, discontinuities in geometry or damage in service. Thus, Fracture Mechanics is introduced as a method for predicting failure of a surface containing a crack. This project is focusing on pre-existing crack with assumption that no microscopic defects are presents. Linear Elastic Fracture Mechanics (LEFM) is used to evaluate the Stress Intensity Factor (SIF) of the specimen. Further analysis is done by incorporating Elastic Plastic Fracture Mechanics (EPFM) to understand the crack growth over period of time. In this study, the important parameters in fracture mechanics such as Stress Intensity Factor (SIF), Crack Mouth Opening Displacement (CMOD), J Integral and stable crack growth are been investigated. A complex loading simulation of NKS-3 specimen is done using finite element modeling. The NKS-3 is a thick-tube used in Pressurized Water Reactor (PWR) which has a circumferential flaw on its inner surface. The cylinder is loaded with axial tensile load and internal pressure combined with thermal shock. A 2-Dimensional Axysimmetric-4 nodes element with focused mesh at the crack tip is employed in the simulation. Several analyses have been done using hardening data at different temperature. A comparison of solution is made for simulation with and without thermal load history. Further analysis showed that the stable crack growth is estimated to be around 3.0mm

Exact solution for linear and nonlinear systems of PDEs by Homotopy-Perturbation method.

In this paper, the homotopy-perturbation method (HPM) proposed by J.-H. He is adopted for solving linear and nonlinear systems of partial differential equations (PDEs). In this method, a homotopy parameter p, which takes the values from 0 to 1, is introduced. When p = 0, the system of equations usually reduces to a sufficiently simplified form, which normally admits a rather simple solution. As p gradually increases to 1, the system goes through a sequence of 'deformations', the solution of each of which is 'close' to that at the previous stage of 'deformation'. Eventually at p = 1, the system takes the original form of the equation and the final stage of 'deformation' gives the desired solution. Some examples are presented to demonstrate the efficiency and simplicity of the method

COPPER LAYER SHEET RESISTANCE EVOLUTION AS A FUNCTION OF POST-SEED PROCESS SELF-ANNEALING TIME

Copper layer metallization is one of the important processes in integrated circuit manufacturing.  One of the issues faced in this process is the proneness of Cu interface diffusion as well as surface oxidation which degrade some of the Cu thin film properties. Due to this concern, most integrated circuit manufacturing facility imposed 12 hours maximum delay time between the Cu seed deposition and   Cu electroplating step. However, there is lack of study and data to justify support this time restriction.  This study investigated the effect of self-annealing time between Cu seeding process and Cu electroplating process to the sheet resistance, reflectance, and stress of the deposited film. The data indicated that the there is no significant deterioration or fluctuation in sheet resistance, reflectance, and stress beyond 12 hours delay time.  This suggested that the imposed 12 hours maximum delay time between Cu seed and Cu electroplating process can be further extended, which will give greater flexibility for the manufacturing scheduling

Cost-effectiveness analysis of PET-CT guided management for locally advanced head and neck cancer

Background: A recent large UK clinical trial demonstrated that positron-emission tomography–computed tomography (PET-CT)- guided administration of neck dissection in patients with advanced head and neck cancer after primary chemo-radiotherapy treatment produces similar survival outcomes to planned neck dissection (standard care) and is cost-effective over a short-term horizon. Further assessment of long-term outcomes is required in order to inform a robust adoption decision. Here we present results of a lifetime cost-effectiveness analysis of PET-CT guided management from a UK secondary care perspective. Methods: Initial 6-month cost and health outcomes were derived from trial data; subsequent incidence of recurrence and mortality was simulated using a de novo Markov model. Health benefit was measured in quality adjusted life years (QALYs) and costs reported in 2015 British pounds. Model parameters were derived from trial data and published literature. Sensitivity analyses were conducted to assess the impact of uncertainty and broader NHS & personal social services (PSS) costs on the results. Results: PET-CT management produced an average per-person lifetime cost saving of £1,485 and an additional 0.13 QALYs. At a £20,000 willingness-to-pay per additional QALY threshold there was a 75% probability that PET-CT was cost-effective, and the results remained cost-effective over the majority of sensitivity analyses. When adopting a broader NHS & PSS perspective, PET-CT management produced an average saving of £700 and had an 81% probability of being cost-effective. Conclusions: This analysis indicates that PET-CT guided management is cost-effective in the long-term and supports the case for wide scale adoption

Trabajo de graduación realizado en la Secretaría Ejecutiva Del Consejo Nacional De Áreas Protegidas -CONAP-, en promoción y fortalecimiento a las actividades de administración forestal dentro de Áreas Protegidas desarrolladas en el Departamento de Manejo Forestal

La presente investigación se realizó en el Departamento de Manejo Forestal de la Secretaria Ejecutiva de CONAP, específicamente en los procesos técnico administrativo del departamento en mención. En el mismo se presenta un Diagnóstico, Investigación y Servicios. Con la coordinación de EPS de la FAUSAC y de la Dirección del Departamento de Manejo forestal se trabajó el diagnóstico interno de la los procesos técnicos administrativos el cual deja un panorama claro de debilidades, deficiencias y fortalezas en los mismos. La propuesta para el fortalecimiento es la elaboración del manual de funciones y atribuciones del departamento de manejo forestal en coordinación con la sección de Capacitaciones del departamento de Recurso Humanos, con el propósito de tener una idea más clara de la función y desempeño del técnico forestal de enlace, así como el apoyo brindado en el tema en el marco del convenio para el transporte comercio de especies amenazadas CITES, y las actividades de administración forestal dentro del SIGAP. Basados en el diagnóstico realizado, se identifican las principales actividades en apoyo al departamento de manejo forestal