bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Fracture Analysis of Individual Sand Particles at High Loading Rates
Authors: Druckrey Andrew M. , Alshibli Khalid , Casem Daniel T. , Huskins Emily 
Published: March 2018

AbstractHigh strain rate loading conditions such as blast, impact, or projectile penetration cause major damages to infrastructure and soils. Sand particles will likely fracture if they are exposed to such loading conditions. Modeling the constitutive behavior of sand deposits when they are subjected to dynamic loading requires a high-fidelity particle-scale analysis, calibration, and validation using experimental measurements. In this paper, natural sand particles with complex morphology, mineralogy, and grain size were randomly selected from the bulk material and were separated based on particle size and mineralogy. Intact particles were first imaged using a desktop X-ray computed tomography (CT) scanner to calculate morphology and provide further input to the mineralogy and internal structure. Each particle was placed between incident and transmitter bars of a Kolsky bar setup, and two optical images (side and top views) were collected to visualize the loading geometry and direction. Each particle was then dynamically loaded to failure, at which load and compressive displacement were measured. Some of recovered particle fragments were imaged using synchrotron microcomputed tomography (SMT) to determine the fracture mode and fracture surface. Weibull statistical analyses were performed and multivariable nonlinear regression was implemented, using particle characteristics as predictors. The paper discusses the influence of morphology, mineralogy, internal structure, and size of particles on dynamic particle failure strength.
Theta Oscillations Organize Spiking Activity in Higher-Order Visual Thalamus during Sustained Attention
Authors: Yu Chunxiu , Li Yuhui , Stitt Iain M. , Zhou Zhe Charles , Sellers Kristin K. , Frohlich Flavio 
Published: March 2018

AbstractHigher-order visual thalamus plays a fundamental but poorly understood role in attention-demanding tasks. To investigate how neuronal dynamics in higher-order visual thalamus are modulated by sustained attention, we performed multichannel electrophysiological recordings in the lateral posterior-pulvinar complex (LP/pulvinar) in the ferret (Mustela putorius furo). We recorded single unit activity and local field potential (LFP) during the performance of the five-choice serial reaction time task (5-CSRTT), which is used in both humans and animals as an assay of sustained attention. We found that half of the units exhibited an increasing firing rate during the delay period before stimulus onset (attention-modulated units). In contrast, the non-attention-modulated units responded to the stimulus, but not during the delay period. Spike-field coherence (SFC) of only the attention-modulated neurons significantly increased from the start of the delay period until screen touch, predominantly in the θ frequency band. In addition, θ power and θ/γ phase amplitude coupling (PAC) were elevated throughout the delay period. Our findings suggest that the θ oscillation plays a central role in orchestrating thalamic signaling during sustained attention.
The Limits to Parapatric Speciation II: Strengthening a Preexisting Genetic Barrier to Gene Flow in Parapatry
Authors: Blanckaert Alexandre , Hermisson Joachim 
Published: March 2018

Abstract
By encompassing the whole continuum between allopatric and sympatric scenarios, parapatric speciation includes many potential scenarios for the evolution of new species. Here, we investigate how a genetic barrier to gene flow, that relies on a single postzygotic genetic incompatibility, may further evolve under ongoing migration. We consider a continent island model with three loci involved in pairwise Dobzhansky–Muller incompatibilities (DMIs). Using an analytic approach, we derive the conditions for invasion of a new mutation and its consequences for the strength and stability of the initial genetic barrier. Our results show that the accumulation of genetic incompatibilities in the presence of gene flow is under strong selective constraints. In particular, preexisting incompatibilities do not always facilitate the invasion of further barrier genes. If new mutations do invade, they will often weaken or destroy the barrier rather than strengthening it. We conclude that migration is highly effective at disrupting the so-called “snowball effect”, the accelerated accumulation of DMIs that has been described for allopatric populations en route to reproductive isolation.
Mito-Nuclear Interactions Affecting Lifespan and Neurodegeneration in aDrosophilaModel of Leigh Syndrome
Authors: Loewen Carin A , Ganetzky Barry 
Published: March 2018

AbstractMitochondrial function requires coordinated activities of interacting proteins encoded in both the nuclear and mitochondrial genomes. Nuclear mutations cause human mitochondrial disorders that commonly exhibit unexplained clinical variability (e.g. age of onset and severity)...Proper mitochondrial activity depends upon proteins encoded by genes in the nuclear and mitochondrial genomes that must interact functionally and physically in a precisely coordinated manner. Consequently, mito-nuclear allelic interactions are thought to be of crucial importance on an evolutionary scale, as well as for manifestation of essential biological phenotypes, including those directly relevant to human disease. Nonetheless, detailed molecular understanding of mito-nuclear interactions is still lacking, and definitive examples of such interactions in vivo are sparse. Here we describe the characterization of a mutation in Drosophila ND23, a nuclear gene encoding a highly conserved subunit of mitochondrial complex 1. This characterization led to the discovery of a mito-nuclear interaction that affects the ND23 mutant phenotype. ND23 mutants exhibit reduced lifespan, neurodegeneration, abnormal mitochondrial morphology, and decreased ATP levels. These phenotypes are similar to those observed in patients with Leigh syndrome, which is caused by mutations in a number of nuclear genes that encode mitochondrial proteins, including the human ortholog of ND23. A key feature of Leigh syndrome, and other mitochondrial disorders, is unexpected and unexplained phenotypic variability. We discovered that the phenotypic severity of ND23 mutations varies depending on the maternally inherited mitochondrial background. Sequence analysis of the relevant mitochondrial genomes identified several variants that are likely candidates for the phenotypic interaction with mutant ND23, including a variant affecting a mitochondrially encoded component of complex I. Thus, our work provides an in vivo demonstration of the phenotypic importance of mito-nuclear interactions in the context of mitochondrial disease.
Associations Between Pediatric Palliative Care Consultation and End-of-Life Preparation at an Academic Medical Center: A Retrospective EHR Analysis
Authors: Stutz Matthew , Kao Roy L. , Huard Leanna , Grotts Jonathan , Sanz Javier , Ross Mindy K. 
Published: March 2018

OBJECTIVES:Our aim in this study was to understand usage patterns of pediatric palliative care (PPC) consultation and associations with end-of-life preparation among pediatric patients who are deceased.METHODS:We reviewed 233 pediatric mortalities. Data extraction from the electronic health record included determination of PPC consultation by using Current Procedural Terminology codes. Diagnoses were identified by International Classification of Disease codes and were classified into categories of life-threatening complex chronic conditions (LT-CCCs). Data analysis included Student’s t test, Wilcoxon rank test, Fisher’s exact test, χ2 test, and multivariable logistic regression.RESULTS:The overall PPC consultation rate for pediatric patients who subsequently died was 24%. A PPC consultation for patients admitted to the pediatric ward and PICU was more likely than for patients cared for in the NICU (31% vs 12%, P &lt; .01) and was more likely for those with an LT-CCC (40% vs 10%, P &lt; .01), particularly malignancy (65% vs 35%, P &lt; .01). Also noted were increased completion of Physician Orders for Life-Sustaining Treatment forms (8 vs 0, P &lt; .01) and increased documentation of mental health disorders (60% vs 40%, P = .02).CONCLUSIONS:Our findings suggest that PPC consultation for patients in the pediatric ward and PICU is more likely among patients with a greater number of LT-CCCs, and is associated with increased Physician Orders for Life-Sustaining Treatment preparation and documentation of mental health disorders. Patients at risk to not receive PPC consultation are those with acute illness and patients in the NICU.
Hypothyroidism and Iodine Deficiency in Children on Chronic Parenteral Nutrition
Authors: Ikomi Chijioke , Cole Conrad R. , Vale Emily , Golekoh Marjorie , Khoury Jane C. , Jones Nana-Hawa Yayah 
Published: March 2018

BACKGROUND AND OBJECTIVES:Iodine is an essential trace element for maintenance of normal thyroid function. Normal thyroid function is a prerequisite for neurocognitive development and growth in children. In the United States, iodine is not routinely added as a trace element in parenteral nutrition (PN). Our objective was to determine the prevalence of iodine deficiency and hypothyroidism in children on chronic PN.METHODS:This was a cross-sectional study of children &lt;17 years of age and using PN for &gt;6 months at a tertiary children’s hospital. Primary outcomes were spot urine iodine concentration (UIC), serum thyrotropin, and free thyroxine levels.RESULTS:Twenty-seven patients were identified (74% male). The median age at screening was 48 months (range: 7–213 months). The median duration on PN was 27 months (range: 11–77 months). Seventeen out of 20 patients (85%) were iodine deficient (spot UIC &lt;100 μg/L), whereas 11 out of 20 patients (55%) were severely iodine deficient (spot UIC &lt;20 μg/L). The prevalence of acquired hypothyroidism (elevated thyrotropin, low free thyroxine, and UIC &lt;100 μg/L) was 33% (n = 8). None of the children with hypothyroidism screened for autoimmune thyroiditis had positive test results. There was no statistically significant association between duration of PN use and development of iodine deficiency (P = .08) or hypothyroidism (P = .96).CONCLUSIONS:Children on chronic PN are at risk for developing iodine deficiency and resultant hypothyroidism; hence, these children should be screened for these outcomes. Further studies are needed to define the temporal onset of iodine deficiency and timing to thyroid dysfunction related to PN.
Encapsulation of metallic iron magnetic nanoparticles by polyacrylamide in water suspensions
Authors: Shankar A. , Safronov A. P. , Beketov I. 
Published: March 2018

Theoretical consideration of the factors of the stability of metallic iron magnetic nanoparticles (MNPs) in water suspensions was done using extended DLVO (Derjaguin-Landau-Verwey-Overbeek) approach based on the balance among Van der Waals, electrostatic, magnetic and steric interactions. Magnetic and steric interactions dominate over other in suspensions of Fe MNPs. To test the theory Fe MNPs with average diameter 84 nm were synthesized by electrical explosion of wire and encapsulated by polyacrylamide in water suspension to provide steric repulsion. It was shown that encapsulation resulted in the efficient diminishing of the aggregation of metallic iron MNPs in water.
Solubility and phase equilibria in the Na, Са || СО3, НСО3–H2O system at 0 °С
Authors: Soliev L. , Dzhumaev M. T. , Dzhabborov B. B. 
Published: March 2018

The information on phase equilibria in the Na, Ca || CO3, HCO3-H2O system at 0 °С, predicted earlier by the translation method, has been obtained experimentally. Dependences of the concentration parameters reflecting phase equilibria are presented in the form of geometric patterns on the solubility diagram for the system studied. The diagram of solubility of the investigated system at 0 °С is constructed for the first time, in which the contours of the crystallization fields of individual phases are outlined, the conditions for their сo-crystallization in the form of curves and points are determined.
Design Of Dry Cask Storage For Serpong Multipurpose Reactor Spent Nuclear Fuel
Authors: Rahayu Dyah Sulistyani , Purwanto Yuli , Salimin Zainus 
Published: March 2018

DESIGN OF DRY CASK STORAGE FOR SERPONG MULTI PURPOSE REACTOR SPENT NUCLEAR FUEL. The spent nuclear fuel (SNF) from Serpong Multipurpose Reactor, after 100 days storing in the reactor pond, is transferred to water pool interim storage for spent fuel (ISFSF). At present there are a remaining of 245 elements of SNF on the ISSF,198 element of which have been re-exported to the USA. The dry-cask storage allows the SNF, which has already been cooled in the ISSF, to lower its radiation exposure and heat decayat a very low level. Design of the dry cask storage for SNF has been done. Dual purpose of unventilated vertical dry cask was selected among other choices of metal cask, horizontal concrete modules, and modular vaults by taking into account of technical and economical advantages. The designed structure of cask consists of SNF rack canister, inner steel liner, concrete shielding of cask, and outer steel liner. To avoid bimetallic corrosion, the construction material for canister and inner steel liner follows the same material construction of fuel cladding, i.e. the alloy of AlMg2. The construction material of outer steel liner is copper to facilitate the heat transfer from the cask to the atmosphere. The total decay heat is transferred from SNF elements bundle to the atmosphere by a serial of heat transfer resistance for canister wall, inner steel liner, concrete shielding, and outer steel liner respectedly. The rack canister optimum capacity of 34 fuel elements was designed by geometric similarity method basedon SNF position arrangement of 7 x 6 triangular pitch array of fuel elements for prohibiting criticality by spontaneous neutron. The SNF elements are stored vertically on the rack canister. The thickness of concrete wall shielding was calculated by trial and error to give air temperature of 30 oC and radiation dose on the wall surface of outer liner of 200 mrem/h. The SNF elements bundles originate from the existing racks of wet storage, i.e. rack canister no 3, 8 and 10. The value of I0 from the rack no 3, 8 and 10 are 434.307; 446.344; and 442.375 mrem/h respectively. The total heat decay from rack canister no 3,8 and 10 are 179.640 ; 335.2; and 298.551 watts. The result of the trial and error calculation indicates that the rack canister no 3, 8 and 10 need the thickness of concrete shielding of 0.1912, 0.1954 and 0.1940 m respectively.Keywords: heat and radiation decay, spent fuel , storage cask.
Elaboración de Chocolate con Espirulina (Spirulina Máxima) Endulzado con Stevia y Frutas Deshidratadas
Authors: El Salous Ahmed , Cadena Nadia , Mosquera Corina , Martínez Tatiana 
Published: March 2018

The present research is based on elaborating a chocolate bar with spirulina sweetened with stevia and dehydrated fruits, generating an alternative of consumption for the people who like the innovation of the chocolate.The treatments were mainly based on concentrations of cocoa dough (Arriba), dehydrated fruits (pineapple, banana, orange) and esperulin, obtaining as a product of the major sensory acceptance that treatment based on 69% cocoa dough, 20% Dehydrated fruit (pineapple and banana) and 5% spirulina. The Tukey's test was applied to the five percent of the probability in which it was possible to differentiate from the others treatments for its excellent attributes in brightness, sweet taste, fruit flavor and residual sweetness that it possessed.Nutritional results were given as protein with 15.47 g, dietary fiber 11.91 g in 100 grams serving. This indicates that it has a high content of protein, fiber and low concentrations of sucrose; because sugar comes from dehydrated fruits. The microbiological parameters showed that the product complies with the Ecuadorian technical standard NTE INEN 621: 2010, giving evidence that it is fit for human consumption. Key words: Spirulina, dehydrated fruits, stevia, cocoa Arriba.
Análisis de variables para el Departamento del Meta - Colombia Respecto de Algunos de sus Municipios
Authors: Fonseca Luis Joaquin Ducon , Garcia Juan Alejandro Chica 
Published: March 2018

The present study corresponds to the analysis of a joint exercise between the Gobernación del Meta, COSMOS Corporation and the Autonomous University Corporation of Nariño, in which 1800 families were surveyed corresponding to 11 municipalities of the department and that focused on those whose lands were inferior to 3 ha, to ensure that a subsequent family agriculture program would be supported. The analysis corresponding to the application of the survey showed that some of the municipalities of the department have major economic deficiencies and that according to the commercial route of the same its economic characteristics are similar geometrically. Equally thanks to this exercise of analytical could find the municipality of greater economic prosperity.Keywords: food safety, state, economic prosperity.
Boussinesq Solitons as Propagators of Neural Signals
Authors: Vargas Edgar Villagran , C. Juan Ramón Collantes , Granados Máximo A. Agüero 
Published: March 2018

We consider certain approximation for determining the equation of motion for nerve signals by using the model of the lipid melting of membranes. The nerve pulses are found to display nonlinearity and dispersion during the melting transition. In this simplified model the nonlinear equation early proposed by Heimburg and coworkers transformed to the well known integrable Boussinesq non linear equation. Under specific values of the parametric space this system shows the existence of singular and regular soliton like structures. After their collisions the mutual creation and annihilation (each other) of nerve signals along the nerve, during their propagation, has been observed.Keywords: Boussinesq equation, singular solitons, single neurons, neural code.
A Comparative Study on Fatigue Damage using a Wave Load Sequence Model
Authors: De Gracia Luis , Osawa Naoki , Tamaru Hitoi , Fukasawa Toichi 
Published: March 2018

Despite that ships get the approval of classification societies and structural members are designed to survive random environmental conditions for twenty or twenty-five years, fatigue crack damage still occurs. Nowadays, the operation based on weather routing programs has become important, not only to avoid adverse sea conditions that can cause damage, time loss or significant speed reduction but also to improve the crew safety. In this paper, S-N based fatigue assessment of a welded joint in an ocean going is performed. It is assumed that the ship sails following a planned route and a route based on weather conditions. Short sea sequences are generated by a storm model called “4G Storm Model”, proposed by one of the co-authors (De Gracia et al., 2017). Stress histories are generated considering the stochastical nature of the wave direction variation. Cumulative fatigue damage is performed following a classification society rule. Based on these results, the effect of ship routing and headings model on the S-N fatigue assessment is discussed. Keywords: Weather routing, fatigue, cumulative damage, storm model, wave sequence model.
Implementación del Emprendimiento en la Universidad Tecnológica de Panamá, y el Perfil del Emprendedor Universitario
Authors: Canto Mariela Salgado , Herrera Vicente 
Published: March 2018

This paper describes the process of transformation formally implemented at the Universidad Tecnológica de Panamá (UTP), to create a platform for fostering and supporting entrepreneurship and the results of the research of the universities entrepreneurship research. The first part of the article presents the conceptual framework on the role that the University should play today, in the face of entrepreneurship. We focus this part of the development of the article on the contributions of author Burton Clark, in his model of Entrepreneurial University and as implemented in the UTP, the common elements of entrepreneurial universities, which were identified by Clark as "transformation paths", which we have adapted and presented their development in a public university. The second part of the article seeks to analyze the profile of the university entrepreneur, that is to say, one wants to know the entrepreneurial intention, so it is important to analyze the attitudes and perceptions of the students of public and private universities in Panama. The results of the study show that there is a greater proportion of positive responses to entrepreneurship in students of private universities, that is to say, a higher positive attitude towards entrepreneurship. This is because they come from private schools, where its treated or discussed more, the aspect of entrepreneurship than in public schools. Globally we can see that there is a great positive entrepreneurial attitude in students, since universities today have several courses of entrepreneurship in the various university careers, something that did not happen 15 years ago. Keywords: Entrepreneur, entrepreneurial university, enterprising attitude, students.
Predicción de la Resistencia de las Conexiones Tipo Canal en Estructuras Compuestas de Acero y Hormigón
Authors: Quevedo Rafael Larrúa , Vergara Ramiro Vargas , Louzado Jennifer Espino 
Published: March 2018

This article deals with channel connections in steel and concrete composite structures, with the main objective of obtaining a new formulation to determine the resistance of this widely used type of connection in the American region. Data from channel connections tests are collected from reliable experimental and numerical sources, and a valid database is created to make predictions by means of different combinations of artificial intelligence techniques, to obtain the most effective cases. Finally, a new formulation is proposed to calculate the resistance of channel connections in solid slab, applying statistical techniques to a database that incorporates experimental, numerical and artificial intelligence results, demonstrating its superiority with respect to the existing formulations in the international literature, by means of statistical measures appropriately applied to the studied case. The proposed methodology is novel and effective, and it can be expanded to other types of structural elements. Keywords: composite structures, connections, resistance, prediction.
Metal Biocorrosion of a Water Well: A Case Study
Authors: Calbo Vicente , Furlong Octavio Javier , Julián Silvia Viviana 
Published: March 2018

Recently, in the city of La Rioja, the Microbiologically-Induced Corrosion (MIC) phenomenon has been confirmed. The last studied case corresponds to the water well of the La Rioja Regional Faculty of the National Technological University (UTN), where the water well facilities showed signs of this phenomenon.These microorganisms catalyze the iron (and magnesium) oxidation reactions, solubilizing or solubilizing and precipitating the metal. Confirming the existence of the MIC phenomenon is essential to mitigate or solve the problem.The laboratory work consisted in processing pipe and pump samples extracted after the well ceased to be used, at three initial temperatures and with different culture media, trying to cultivate, reproduce, and isolate and identify the different species.Thus, through culture methodology, the existence of a mixed flora featuring iron bacteria and sulfate-reducing bacteria was confirmed.Complementary Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) spectroscopy scans allowed to visualize the bacteria, the damage to the analyzed material, and the morphology of the bioprecipitation.This little-known phenomenon causes significant economic losses and should therefore be taken into account in the execution as well as the maintenance of wells. Keywords: Metal Corrosion, Microbiologically Induced Corrosion, Water Well, Bacteria.