bluuebunny/crossref_metadata_2025 huggingface dataset:
E-training based on Determination of Education and Training Models of Early Childhood Teachers Education Programs
Authors: Siswanto Yudi , Sutarto Joko , Mulyono Sungkowo Edy
Published: September 2018

The success of education and training is determined from all components themselves. E-training as a medium of education and training is one of the aspects of achieving the goals of education and training effectively and efficiently. The purpose of this study is to analyze the e-training based on Determination of Education and Training Models of Early Childhood Teachers Education Programs. This research approach is a quantitative approach using Structural Equation Modeling (SEM). This research was carried out at the Center for Early Childhood Education and Society Education Education in Central Java. The respondents of this study were Early Childhood teachers who attended e-training based education and training which number were 183 respondents in total by using non-probability sampling techniques. Data collection technique used was questionnaire. Data analysis technique was using SEM AMOS software. The results of the study show that individual differences, job analysis and principles of learning indirectly have a positive and insignificant effect on the effectiveness of education and training through the use of e-training. Motivation, active participation, trainer competence, indirect training methods indirectly have a positive and significant effect on the effectiveness of training through the use of e-training. E-training has a positive and significant effect on the effectiveness of training
Identification of Non-Education Tutors Difficulty In Education Process Of Learning Study Groups
Authors: Nainggolan Elizon , Irwan Mahfuzi
Published: September 2018

This study aims to find out what are the difficulties of tutors who hold degrees non-educational in the learning process of study group in Binjai. This study used a descriptive qualitative research method with the research subjects were two tutors of learning groups holding non-education bachelor’s degrees in Binjai city which were determined purposively. Data collected by interview, observation and documentation techniques. Collected data is analyzed by steps: data reduction, data presentation, conclusion and verification. The results showed that in the package B learning group learning process in Binjai City, tutors with non-education degrees had many difficulties in the learning process. The conclusion that can be obtained in this study is the difficulties identified are located in: (1) the learning planning process, namely the difficulty in preparing RPP and syllabus. (2) the process of implementing learning, namely difficulties in preliminary activities, core activities (exploration, elaboration, confirmation), closing activities, and (3) assessment of learning outcomes.
Productive process improvement to elaborate cane train baskets, using Coloured Petri nets
Authors: Caratar-Chaux Jesús Filander , Cano-Buitrón Ruth Edmy , Garcia-Melo José Isidro
Published: September 2018

The search for improvements in production processes that serve a variant market with flexibility and profitability is a subject widely discussed in diverse sectors of the industry. The approach to this type of problem frequently requires a structured and detailed formal study of production systems using tools such as Coloured Petri Nets (CPN). This tool provides a method to propose and evaluate improvements in the system. Considering the production system as a system that evolves through discrete events, this article presents a procedure with a Top-Down approach to identify, simulate and evaluate the current state of a production system using CPN, this model is used to study improvements in order to analyze the impact on the performance of the production system.
Application of OpenFoam solver SettlingFoam to bedload sediment transport analysis
Authors: Carrillo-Serrano Veróníca Margarita , Pacheco-Tobar Esteban Alonso
Published: September 2018

El transporte de sedimento es un proceso importante para ríos naturales, su determinación es un proceso complejo debido a la variabilidad y a la naturaleza cambiante de los factores que intervienen. Como una contribución a la descripción de este fenómeno y para enfatizar los problemas, las necesidades y las potencialidades de los enfoques numéricos, el solucionador settingFoam (OpenFoam) es utilizado para simular el transporte de sedimentos en un canal rectangular. El modelo utilizado constituye una simplificación de basada en la aplicación de un solo parámetro (alpha) para determinar las características de la mezcla fluido-sedimento. Alta variabilidad se reporta en los resultados para diferentes valores de alpha, sin embargo, existe poca información para determinar los valores apropiados para éste parámetro. A pesar de que el procedimiento aplicado y los resultados obtenidos deben ser tomados como referencia, este estudio provee criterios valiosos para la futura investigación de este tema tan complejo.
Effect of fly ash and silica fume on rheology, compressive strength and self-compacting in cement mixtures
Authors: Correa-Yepes Jaime Arturo , Rojas-Reyes Néstor Ricardo , Tobón Jorge Iván
Published: September 2018

En esta investigación se evaluó el efecto de la adición de humo de sílice (SF) y cenizas volantes (FA) al cemento Portland ordinario (OPC) de manera individual y combinada, sobre la reología, resistencia a la compresión y capacidad de autocompactación en mezclas de cemento. Se realizó la caracterización fisicoquímica de las materias primas mediante FRX, SEM y DTP. Se hizo el análisis reológico para determinar el esfuerzo de fluencia y la viscosidad plástica. Se midió la resistencia a compresión a 7 y 28 días de curado normal. Por último, se realizó la medición de la capacidad de autocompactación por medio cono en V. Se encontró que la FA influye de manera positiva al reducir el esfuerzo de fluencia y los tiempos de prueba en la autocompactación, pero disminuye la resistencia a la compresión respecto a la muestra control. La adición de SF incrementa el esfuerzo de fluencia y los tiempos de autocompactación, pero influye de manera positiva en la resistencia a la compresión. Al analizar las combinaciones de adiciones de FA y SF los efectos de cada adición se mantienen permitiendo encontrar un rango de adición que entregó valores eficientes tanto para el desempeño en estado fresco como endurecido de las pastas.
Structural, thermal, rheological, morphological and mechanical properties of thermoplastic starch obtained by using hyperbranched polyester polyol as plasticizing agent
Authors: Guzmán Manuel , Murillo Edwin A.
Published: September 2018

En este trabajo, se evaluó el efecto de la proporción de un poliéster poliol altamente ramificado (HBP) de cuarta generación en las propiedades estructurales, térmicas, reológicas, morfológicas y mecánicas de mezclas de almidón de yuca/HBP (TPS). Para este propósito las relaciones de almidón:HBP empleadas para preparar los TPS fueron: 30:70 (TPS30), 40:60 (TPS40) and 50:50 (TPS50). Por análisis infrarrojo (IR) se observó que la presencia de HBP produjo un desplazamiento en las absorciones de los enlaces C-OH, C-O and C-O-C del TPS. El análisis de difracción de rayos X mostró que la cristalinidad del almidón es tipo A y B, las cuales incrementaron con la cantidad de HBP. La temperatura de transición vítrea (Tg) de los TPS, incrementó con el contenido de HBP, pero la estabilidad térmica y la viscosidad (a una frecuencia angular de 1 Hz) presentaron un comportamiento opuesto. El análisis de microscopia de barrido electrónica (SEM), reveló que la estructura granular del almidón no fue completamente desestructurada.
El análisis del discurso multimodal: una comparación de propuestas metodológicas
Authors: Cárcamo Morales Benjamín
Published: September 2018

El artículo propone la comparación de algunas de las propuestas más relevantes del análisis del discurso multimodal, con el fin de presentarlas y establecer contrastes en relación con la implementación de sus supuestos. En particular, la presente revisión teórica muestra tanto puntos de encuentro como diferencias entre las miradas de la propuesta de los artefactos multisemióticos, el enfoque composicional, la teoría socio-semiótica de multimodalidad y la metáfora multimodal. Los resultados del análisis comparativo permiten comprender la lógica detrás del análisis del discurso multimodal y los diversos caminos que pueden seguir los investigadores interesados en esta área. Además, estos hallazgos contribuyen a una mirada más pormenorizada de las maneras en las cuales el análisis del discurso modal ha sido implementado en los estudios empíricos de la disciplina.
Association between the polynoid Malmgreniella variegata (Polychaeta: Polynoidae) and Ophionereis reticulata (Ophiuroidea: Ophionereididae) first record to the Southeastern Caribbean
Authors: Gómez-Maduro María Cecilia , Díaz-Díaz Oscar
Published: September 2018

The worms Malmgreniella variegata has been found as commensal of Ophionereis reticulata in Florida and Belize.  Here we report the association in Playa Piscina (Arapo Islands), Venezuela. Rev. Biol. Trop. 65(Suppl. 1): S85-S91. Epub 2017 November 01.
A supplementary description of Brisaster iheringi (Spatangoida: Schizasteridae) from the Miocene of Patagonia Argentina
Authors: Martínez Sergio , Del Río Claudia J.
Published: September 2018

Neogene Argentinean echinoids are important biostratigraphic tools. New specimens of Schizaster iheringi (de Loriol, 1902) from Early Miocene sedimentites (Chenque Formation, Patagonia, Argentina) allowed us to improve its original description, providing for the first time details of the apical disc and the oral side of  test. The species is included into the genus Brisaster: the first unquestionable documented reference to the taxon from the Neogene of Argentina. All previously reported specimens of this species are evaluated, concluding that the stratigraphic range of the genus Brisaster in Patagonia must be restricted to the Early Miocene. Rev. Biol. Trop. 65(Suppl. 1): S137-S146. Epub 2017 November 01.
Reproductive cycle of the sea cucumber (Isostichopus fuscus) and its relationship with oceanographic variables at its northernmost distribution site
Authors: Pañola-Madrigal Abigail , Calderon-Aguilera Luis E. , Aguilar-Cruz Carlos A. , Reyes-Bonilla Héctor , Herrero-Pérezrul María Dinorah
Published: September 2018

The brown sea cucumber Isostichopus fuscus is highly prized and intensively fished, yet no studies of its reproductive cycle at its northernmost distribution site exist. To characterize its reproductive cycle, monthly surveys (Oct 2014-Dec 2016) that included gonad collection were conducted in 118 sites along the eastern coast of Baja California, including islands from Bahía San Luis Gonzaga (29o 49’ 14.18” N, 114 o 3’56.17” W) to the 28th parallel north. A total of 2 808 sea cucumber specimens were measured (mean length ± SD = 21.4 ± 6 cm) and weighed (375.6 ± 249 g). Seven hundred and seventeen organisms were dissected but only 553 gonads were suitable for processing through histological analysis to identify sex and developmental stage. Of these individuals, 224 were female, 162 were male, 157 were undifferentiated and 10 were hermaphrodites, resulting in a sex ratio that was significantly different from 1:1 (χ2 = 36.63, P = 0.03, df = 23). There was no statistical difference (p > 0.05) of either size or weight between males and females, but females were larger than males. The length-weight relationship observed was W = 0.18L2.4, r2 = 0.82, p <0.05 while the size-at-first-maturity was 16 cm. Five gonad stages were identified: 28% undifferentiated, 9% gametogenesis, 15% mature, 19% expulsion and 29% post-expulsion. The Oocyte Theoretical Diameter (OTD) was estimated by measuring the area of 10 291 oocytes, finding 2 307 individuals in oogenesis (mean ± SD of 65.3 ± 19.7 µm), 3 630 in maturity (66.0 ± 17.8 µm), 3 756 in spawning (73.8 ± 14.6 µm) and 868 in post-spawning (49.18 ± 20.7 µm). Modal progression analysis shows that oocytes increase 23% in size from oogenesis to maturity, and decrease 9%in size from maturity to spawning and, on average, oocytes are 72% smaller post-spawning that during spawning. Rev. Biol. Trop. 65(Suppl. 1): S180-S196. Epub 2017 November 01.
Reproductive biology and energetics of the brooding sea star Anasterias antarctica (Echinodermata: Asteroidea) in the Beagle Channel, Tierra del Fuego, Argentina
Authors: Pérez Analía F. , Fraysse Cintia , Boy Claudia C. , Epherra Lucia , Javier Calcagno
Published: September 2018

The brooding sea star Anasterias antarctica is distributed from the coast of Patagonia to the northern Peninsula of Antarctica. In the Beagle Channel, the females of A. antarctica brood their eggs for seven months and do not feed during this period. The endoparasite Dendrogaster argentinensis (Crustacea: Ascothoracica) causes castration in several species of Anasterias. We randomly collected four samplings of adults in May, August and October (brooding period) and January (non-brooding period). The gonad (GI) and pyloric caeca index (PCI) were calculated as organ wet weight (g) x 100/total wet weight (g). Each individual was sexed by microscopic examination of the gonads. Sex ratio, brooding females/non-brooding females and mature females/non-mature females ratios was 1:1. The male GI reached maximum values in January, when most individuals were sexually mature. The GI of non-brooding females reached its maximum during October when it was significantly higher than those from brooding females. The PCI was minimum in October, being lower in brooding females (August and October). During the non-brooding period, mature females had a significantly higher GI than non-mature females. The PCI did not vary neither between males, nor between mature and non mature females. By the end of the brooding period, non-brooding females showed a higher GI than the brooding females. This is explained by proliferation and increase of the oocytes size of non-brooding females. Mature females showed an incremented GI with presence of mature oocytes, while non-mature females exhibited more abundance of previtelogenic oocytes. Males showed synchronicity in reproductive condition. The females that have not brooded presented a process of active gametogenesis, reaching the summer with a high GI, therefore becoming mature females. Females that had brooded were probably lacking energy for new gonadal maturation. The pyloric caeca would be performing the role of a reserve organ in the brooding females, decreasing its size during the brooding period. Prevalence of D. argentinensis in A. antarctica was 11.06%. As this parasite was recorded in sea stars lacking gonads, these infected hosts could have been castrated. Rev. Biol. Trop. 65(Suppl. 1): S221-S232. Epub 2017 November 01.
New records of marine planktonic invertebrates from the Caribbean coast of Costa Rica
Authors: Carrillo-Baltodano Allan , Morales-Ramírez Álvaro V. , Sibaja-Cordero Jeffrey A. , Cortés Jorge
Published: September 2018

The coral reef at Cahuita National Park in the Caribbean coast of Costa Rica represents very diverse marine ecosystem. Most of this diversity knowledge has been the result of benthic surveys, while very little is known from pelagic studies. A zooplankton survey sampling was conducted monthly from September 2010 to August 2011, finding new records of marine invertebrates: 32 for the Caribbean coast of Costa Rica, seven for Costa Rican water and 16 for the Caribbean coast of Central America. These reports include the hoplitomella larva of the sponge Thoosa sp., larval stages of three lophophorates, seven families, five genera and six species of polychaetes, a juvenile of the lancet Branchiostoma (Phylum Chordata, Subphylum Cephalochordata) and four pelagic chordates. Analyzing the zooplankton of Cahuita, is an essential approach to studying not only the diversity, but also enhances the possibility of better understanding the ecological goods and services that the coral reef can provide.
Ammonium and phosphate removal using batch laboratory cultures by microalgae and cyanobacteria isolated from Costa Rica water bodies
Authors: Campos-Rudin Manuel , Silva-Benavides Ana Margarita
Published: September 2018

This research analyzed three green microalgae (Scenedesmus sp., Chlamydomonas sp., and Chlorella sp.) and two cyanobacteria (Synechocystis sp. as unicellular strain and Nostoc sp. as filamentous strain) native from Costa Rica to remove high concentrations of ammonium and phosphate. Cultures were exposed for 120 h to initial concentrations of 70 mgL-1 ammonium and 9 mgL-1 phosphate, under constant light intensity of 60 µmol m-2s-1. Chlorella sp. showed the highest growth rate, followed by Chlamydomonas sp. and the cyanobacteria Nostoc sp. In contrast, Scenedesmus sp. and Synechocystis sp. cultures grew less than the other ones. The highest percentage of ammonium removal was achieved with Chlorella sp. followed by Chlamydomonas sp. and Synechocystis sp., then Scenedesmus sp. and Nostoc sp. Microalgae removed totally the initial phosphate concentration within 72 h, while cyanobacteria Synechocystis sp. and Nostoc sp. removed phosphate partially. These microorganisms are promising for wastewater reclamation.
Fish assemblages and their ecological traits along an elevational gradient in the Río Pacuare, Costa Rica
Authors: Picado Barboza Jorge , Umaña Villalobos Gerardo
Published: September 2018

Between May 2004 and May 2005, we sampled fish in 19 sites, grouped in four elevations, ranging from the river mouth to 650 m.a.s.l. in the Río Pacuare, Caribbean versant of Costa Rica. Changes in the distribution and composition of the fish fauna, as well as patterns of alpha and beta diversity along an elevational gradient were assessed. Additional analyses of habitat preferences, trophic guilds, functional groups and general ecology for the most abundant species are included. All fish captured were classified into 22 families, 43 genera and 53 species. The most abundant family was Characidae, followed by Gobiidae, Mugilidae, Poeciliidae and Heptateridae, which together comprise 87.9 % of all sampled individuals. Elevation shows an inverse effect on species diversity, we observed a monotonic decrease in species richness with increasing elevation (p < 0.05), as reported in other tropical rivers. According to our results, in the Río Pacuare the total fish fauna diversity is found within the first 500 m.a.s.l. Species turnover increases with elevation, while nestedness decreases. Turnover was dominated by the loss of species rather than gain; the higher species loss was registered between the river mouth and the lower river reach (< 100 m.a.s.l.). Seven species can be classified as typical or core species (Astyanax aeneus, Sicydium altum, Agonostomus monticola, Poecilia gillii, Brycon costaricensis, Rhamdia laticauda and Joturus pichardi) along the elevation gradient. The habitat availability and the integration of ecomorphological, feeding and reproductive traits help to explain better the elevation distribution of the complete set of species observed. Although it is possible to identify groups of species characteristic of each reach of river, this does not mean that they are isolated from each other. Natural drift and movement along the river of some species during their life cycle, especially S. altum, A. monticola and J. pichardi, are key processes linking the whole watershed. The present study constitutes a first step in documenting and understanding the distribution and composition of fish assemblages in a watershed that is relatively intact and well-conserved in the Caribbean versant of Costa Rica.
Spatial distribution of macrofauna within a sandy beach on the Caribbean coast of Costa Rica
Authors: Sibaja-Cordero Jeffrey A.
Published: September 2018

Knowingthe spatial pattern and densities of individuals in apopulation is basic to understand ecology such as their response to environmental gradients.The main goal of the present study is to describe the abundances and distribution of thebenthicfauna in thelower intertidallevelof asandybeach at PacuareReserve, Caribbean Coast, Costa Rica. The count data of five taxa (in 29 cores) was analyzed to determine their spatial distribution. Two species of polychaetes were found: the first, Scolelepis (Scolelepis) squamata (O. F. Mueller, 1806) was common in the center of the beach in an aggregated pattern. The second, Pisionidens indica (Aiyar & Alikunhi, 1940) was present in low densities with a random distribution pattern. Moreover, two isopods were found: Excirolana braziliensis Richardson, 1912 was randomly distributed along the beach while Ancinus brasiliensis Lemos de Castro, 1959 appeared only in two stations. A meiofaunal nemerteanattached tograins of sand was the mostcommon organismin theintertidal zone, showing a clumped pattern. Thepatches ofabundancewithin the beachcould be duetoamorphologicchangethat imposes the influenceof thestrongsurf conditions. Moreover, food resource distribution, niche partitioning or competition within the same tide level could influence the different patterns of distribution found in the sediment among the species. In these unstable sediments, the fauna was limited to few opportunist taxa well adapted to withstand mechanical disturbances.
Estructura espacial y temporal de la ictiofauna del Estero de Tamarindo, Parque Nacional Marino Las Baulas, Costa Rica
Authors: Ortiz-Araya Scarleth , Chacón-Guzmán Jonathan , Víquez-Portugués Rigoberto , Sibaja-Cordero Jeffrey A.
Published: September 2018

Abstract: Spatial and temporal structure of the ichthyofauna of the Estuary of Tamarindo, Las Baulas National Marine Park, Costa Rica. Fish communities in mangrove areas have an ecological and socio-economic importance. The management in this kind of habitat is based on the data information about spatial and temporal patterns. The main goal of the study is determinate the spatial and temporal structure of the ichthic community from Tamarindo mangrove area. Six samplings trips were conducted from August 2009 to June 2010, at five mangrove stations using four different fishing gear. Also, environmental variates were recording (temperature, oxygen, salinity, pH, and water transparency). A total of 1357 individuals belonging to 59 species of 28 families were identified. Carangidae and Lutjanidae were more richness families, and the most abundant were Poecilidae, Mugilidae and Clupeidae. Poeciliopsis elongata was the most abundant species. Temporally, the diversity reached a minimum of 1.55 in December and a maximum of 1.96 in April. The richness presented a minimum of 22 species in February and a maximum of 25 in December. Spatially, the diversity reached a minimum of 1.96 in the mouth of the estuary and a maximum of 2.79 in mid estuary; the richness a minimum of 24 species inner the estuary and a maximum of 30 at mid estuary. Additionally, a temporal pattern of succession of species was determined. The fish community shows change in the similarity in their species composition from the mouth to the inner part of the estuary. At inner of the estuary the abundance was low, in contrast with the richness, diversity and equitability. Finally, nursery process for some key species for fisheries occurs in this estuary; made it fragile and susceptible to pollution and anthropogenic impacts, because their short mangrove area and shallow depth. Rev. Biol. Trop. 66(Suppl. 1): S255-S268. Epub 2018 April 01.
Desarrollo costero y ambientes marino-costeros en Bahía Culebra, Guanacaste, Costa Rica
Authors: Sánchez-Noguera Celeste , Jiménez Carlos , Cortés Jorge
Published: September 2018

Abstract: Coastal development and marine ecosystems in Culebra Bay, Guanacaste, Costa Rica. Culebra Bay (North Pacific, Costa Rica) is under an accelerated process of coastal development since the implementation of the large-scale tourism development Gulf of Papagayo Project. This study aims to identify changes in the health status of marine ecosystems within the bay, during a 18yr time period (1993-2011). The high sanitary and aesthetic quality of this bay has remained constant through time. However, coral reefs are degraded and dead coral accounts for more than 65 % of benthic coverage, likely due to a combination of natural and anthropogenic factors. During the study period, only one of the developers consortium has proved their commitment to accomplishing the goals of sustainable development, as established in the bay’s Master Plan, through the practice of social and environmental programs. Management of natural resources in Culebra Bay requires the implementation of specific actions to promote the ecosystems’ recovery, with inclusion of all stakeholders. It must consider the current use of natural resources and include water waste management and environmental education programs. Rev. Biol. Trop. 66(Suppl. 1): S309-S327. Epub 2018 April 01.
Crossover trial of an audience response system application for smartphone in undergraduate medical students
Authors: Lours Camille , Sujobert Pierre
Published: September 2018

This article was migrated. The article was marked as recommended. Objectives: Audience response systems (ARS) using dedicated devices have been shown to enhance interactivity, leading to an increase in knowledge acquisition. ARS applications for smartphones are easier to use, but the benefits of these applications might be negated by deleterious effects of smartphone usage on concentration. We investigated whether an ARS smartphone application (SocrativeTM) is feasible and increases student satisfaction and knowledge acquisition. Methods: We performed a crossover study in the setting of a hematology course for second-year medical students. Two hundred and forty nine students were included in the study and analyzed for their access to the ARS application through a smartphone. The same interactive lectures were proposed by the same teachers. The first group (n=119) was asked to answer questions with the ARS application during the first 3 lectures, and without the application during the last 3 lectures; and conversely for the second group (n=130). The analysis of the final results was restricted to 146 students having attended to at least 5 of the 6 lectures and having a smartphone enabling the use of the ARS application. Student opinion was measured through questions based on a Likert scale, and knowledge acquisition was measured at short and long-term through multiple choice questions assessing either the first three lectures or the last three lectures. Results: Most of the students (86%) had a smartphone enabling the use of the application. They were satisfied by the use of the application (93%), and found that it increased both interactivity (92%) and concentration (68%). There was no difference in knowledge scores at short or long term. Conclusion: The use of an ARS application for smartphone is feasible and increases the satisfaction of the students, their concentration and the interactivity of the lectures. However, this does not translate into a measurable increase in knowledge acquisition.
Sahil güvenlik yüzer unsurlarının arama ve kurtarma önceliklerinin tanımlanmasında analitik ağ süreci kullanımı
Authors: UZUN Günay , KABAK Mehmet
Published: September 2018

Denizde arama ve kurtarma (AK) sahil güvenliğin en yaygın ve oldukça önemli görevlerinden biridir. Sahil güvenlik, denizde tehlikede olduğu ihbar edilen vasıta ya da insanlar için derhal araç görevlendirebilecek imkana sahip olmalıdır. Sahil güvenlik yüzer unsurlarının tasarımı doğal olarak mühendislik değişikliklerini içerir ve AK görevi için ideal olan tek bir unsur tipi dizaynı mümkün değildir. Son dönemde Ege Denizini kullanan göçmen sayısındaki artış, Türk Sahil Güvenlik yüzer unsurlarının özellikle AK konusunda bilimsel yöntemlerden yararlanarak maksimum fayda sağlayacak şeklide görevlendirilmesi ihtiyacını ortaya çıkarmıştır. Bu çalışmanın amacı, Sahil Güvenlik Komutanlığında sahil güvenlik yüzer unsurlarının AK durumu ve önceliklerini tanımlamak için Analitik Ağ Süreci (ANP) ile Faydalar, Fırsatlar, Maliyetler ve Risklere (BOCR) dayalı bir model önermektir. Bu bütünleşik yaklaşım, AK görevlerine göre yüzer unsur tiplerinin ağırlık ya da öncelik olarak da adlandırılan boyutsuz ölçümlerini bulmamıza olanak vermektedir. Bu çalışma sahil güvenlikte AK görevlerine yönelik karar verme problemleri için temel girdiyi sağlamaktadır. Sonuç olarak KAAN 29/33, SAR 33/35 ve 80 sınıfı botların AK görevi için daha uygun oldukları tespit edilmiştir.Search and rescue (SAR) at sea is one of the most common and extraordinarily important missions for the coast guard. The coast guard must have the capability of assigning a vessel immediately for reported vessel or people in distress at sea. Coast guard surface vessel design inherently involves engineering trade-offs and there is not a single vessel type design, which is ideal for SAR mission. The significant increase in the number of immigrants crossing the Aegean Sea in recent years has revealed the fact that the Turkish Coast Guard assets should be assigned by utilizing scientific methods so as to provide maximum benefit. The purpose of this study is to propose a model based on Analytic Network Process (ANP) and Benefits, Opportunities, Costs and Risks (BOCR) to determine the SAR status and priorities of coast guard surface vessels in Turkish Coast Guard command. This integrated approach allows us to find dimensions, measurements called as weights or priorities of the surface vessel types according to SAR task. This study provides the basic input for decision making problems related to SAR mission. Consequently, KAAN 29/33, SAR 33/35 and 80 class of boats have found to be more suitable for SAR task.
OLED TV için yarım köprü LLC rezonans dönüştürücü güvenilirlik analizi
Authors: NİL Metin , ÖZTÜRK Yavuz , ÖZDEMİR Sadık , SÖZEN Hasan , NİL Mustafa
Published: September 2018

Bu çalışmada 65’’ ekran AMOLED TV için yarım köprü LLC rezonant DC-DC dönüştürücü tasarımı gerçekleştirilmiştir. Yapılan tasarımın ana amacı, optimum güvenilirlik düzeyinin elde edilerek uygun MTBF (Mean-time between failure – arıza yapana kadar ortalama ömür süresi) süresine ulaşabilmektir. Tasarlanan güç kartının ve kritik devre bileşenlerinin termal, EMC ve elektriksel testlerini kapsayan güvenilirlik testleri gerçekleştirilmiştir. Ayrıca farklı anahtarlama frekanslarında devrenin çalışma karakteristiğini incelemek amacıyla PSIM programı kullanılarak benzetim analizleri gerçekleştirilmiştir. Tüm bu benzetim ve deneysel çalışmalar sonucunda 120.215 saat MTBF değeri ile on yılın üzerinde üst düzey güvenilirlik elde edilmiştir.
The Role of Visuospatial Representation to Improve Student’s Conceptual Mastery based on Gender in Learning Human Urinary System
Authors: Atikah A , Sanjaya Yayan , Rustaman Nuryani
Published: September 2018

Study of this research investigates the role of visuospatial representation using Wimba model to improve student’s conceptual mastery based on gender in learning Human Urinary System. The method used in this research was experimental research with matching pretest-posttest comparison group design. The sample was taken based on gender classes consisting of boys class (n=21) and girls class (n=9) in one of Bilingual School in Bandung. The quantitative data of this research was investigated through the objective test, while the supportive qualitative data gathered through Likert-Scale. The conceptual mastery of both classes measured based on Bloom’s taxonomy cognitive domain through an objective test. Data processing was done by independent sample t-test. The result of this research shows that there are significant differences in conceptual mastery improvement between girl class and boy class by using visuospatial representation as a model. The research indicates that girl class is outperformed in conceptual mastery almost in each cognitive domain than boy class, and girl class also shows more positive responses toward learning using visuospatial representation than boy class.
Using Physics Education Technology as Virtual Laboratory in Learning Waves and Sounds
Authors: Maulidah Shopi Setiawati , Prima Eka Cahya
Published: September 2018

This research was intended to analyze the use of Physics Education Technology (PhET) as a virtual laboratory in learning waves and sounds. The analysis was in terms of the implementation of waves on a string student activity as a lesson plan, the profile of students’ cognitive, and the profile of science laboratory environment. The method which is used in this research was a descriptive method with methodological triangulation as the research design. The sample was taken on the convenient situation at grade 8 in an international school in Bandung. According to the analysis of the result, the waves on a string student activity can be adopted as the lesson plan with several recommendation to be improved such as in part A, changing some sentences in the data table, changing some settings in obtaining data activity, and adding clear example in determining the base and peak point in measuring the height of wave at start and at the end. Moreover in part B, adding clear instruction on how to use the ruler to measure the wavelength, and changing the picture to obtain the data of wavelength with the picture of simulation with the instructed setting are important. In part C, it needs to add the instruction to do the practice session together with the teacher and to add the instruction to make the starting point in counting the wave similar in each trial. The use of Physics Education Technology (PhET) as a virtual laboratory in learning waves and sounds shows the favorable result on both the cognitive aspect and science laboratory environment.
Dynamic diagnostic strategy based on reliability analysis and distance-based VIKOR with heterogeneous information
Authors: Li J. , Duan R.
Published: September 2018

This paper presents a dynamic diagnostic strategy based on reliability analysis and distance-based VIKOR with heterogeneous
information. Specifically, the proposed method uses a dynamic fault tree (DFT) to describe the dynamic fault characteristics and
evaluates the failure rate of components using interval numbers to deal with the epistemic uncertainty. Furthermore, DFT is
mapped into a dynamic evidential network (DEN) to calculate some reliability parameters and these parameters together with test
cost constitute a decision matrix. In addition, a dynamic diagnostic strategy is developed based on an improved VIKOR algorithm
and the previous diagnosis result. This diagnosis algorithm determines the weights of attributes based on the Entropy concept to
avoid experts’ subjectivity and obtains the optimal ranking directly on the original heterogeneous information without a transformation process, which can improve diagnosis efficiency and reduce information loss. Finally, the performance of the proposed
method is evaluated by applying it to a train-ground wireless communication system. The results of simulation analysis show the
feasibility and effectiveness of this methodology
Fault diagnosis and identification in the distribution network using the fuzzy expert system
Authors: Kaluđer S. , Fekete K. , Jozsa L. , Klaić Z.
Published: September 2018

In this paper, a fuzzy expert off-line system has been developed for fault diagnosis in the distribution network based on the structural and functional operation of the relay and circuit breakers. Functional operations (correct operation, false operation and
failure to operate) of the relays and circuit breakers are described by fuzzy logic. Input data for the proposed fuzzy expert fault diagnosis system (FDS) are status and time stamps of the alarms, associated with relays and circuit breakers. The diagnostic system
from a huge number of alarms sets, logically organizes and quantifies the diagnosis. FDS can diagnose correct operation, false
operation and failure to operate of the relays and circuit breakers. Also, it can identify and quantify fault location based on the
Hamacher’s operator of a fuzzy union. The additional contribution of this paper is in modeling unknown information using linear
fuzzy membership function. Statuses of certain components may be unknown due to telemetry failures or are simply unavailable to
the operator and proposed FDS can make diagnosis in such a situation. Developed fuzzy expert FDS is tested on the two examples
of faults in real life distribution network
The experimental tests on the friction coefficient between the leaves of the multi-leaf spring considering a condition of the friction surfaces
Authors: Hryciów Z. , Krasoń W. , Wysocki J.
Published: September 2018

In this study are presented the results of the simulation tests of the friction pairs occurring between the spring leaves while considering a condition of the mating surfaces and an impact of the velocity of their mutual dislocation on the values of the friction
coefficients. It has been proposed a methodology in respect of a determination of the coefficients of the static and kinetic friction.
Two kinds of the specimens have been prepared for the tests, which have been cut out from a spring leaf of the prototype spring –
they have created the model friction pairs. The condition of the specimen surface and their selected mechanical properties have
been evaluated. During the experimental tests have been considered: four sliding velocities, four variants of the surface conditions
and two values of the normal load. The tests of the friction pairs have been performed at the laboratory stand for measuring the
friction force. The results of the tests have been presented in a form of the time courses of friction force, graphs and tabular summaries of the friction coefficients. It has been conducted a comparative analysis of the results in order to determine an influence
of the test results on the values of the determined friction coefficients. The proposed research conditions are approximate to the
typical operating conditions of the road vehicles.
Model for forecasting the geometry of the floor panel of a passenger car during its operation
Authors: Gonera J. , Napiórkowski J.
Published: September 2018

A number of vehicle users pay attention to the impact of changes in the car body geometry during long-term use on the safety
level. However, this issue has not been properly dealt with in research studies. The aim of this study was to identify changes in the
floor panel, to develop a model to forecast the geometry during the car use and to identify the points which undergo the maximum
displacement. The paper presents the effect of the car mileage on the floor panel condition, taking into account variable environmental factors. In the course of the study, the position of points fixing the front suspension, front bench and rear suspension was
determined, as was the position of points situated on parts of the load bearing structure of the car body. The results were used to
develop a model for forecasting changes of the floor panel geometry during car use. The probability of changes in the floor panel
geometry was found to increase with the mileage. The probability of reaching the maximum permissible geometric changes (3
mm) in a floor panel is accurately described by the probabilistic model in the form of the Rayleigh distribution. Diverse models
of the floor panel geometry changes were obtained depending on the environmental conditions and type of the base points under
analysis.
Fault diagnosis for complex systems based on reliability analysis and sensors data considering epistemic uncertainty
Authors: Duan R. , Lin Y. , Zeng Y.
Published: September 2018

This paper presents an information fusion method to diagnose system fault based on dynamic fault tree (DFT) analysis and
dynamic evidential network (DEN). In the proposed method, firstly, it uses a DFT to describe the dynamic fault characteristics
and evaluates the failure rate of components using interval numbers to deal with the epistemic uncertainty. Secondly, qualitative
analysis of a DFT is to generate the characteristic function via a traditional zero-suppressed binary decision diagram, while
quantitative analysis is to calculate some importance measures by mapping a DFT into a DEN. Thirdly, these reliability results are
updated according to sensors data and used to design a novel diagnostic algorithm to optimize system diagnosis. Furthermore, a
diagnostic decision tree (DDT) is obtained to guide the maintenance workers to recover the system. Finally, the performance of the
proposed method is evaluated by applying it to a train-ground wireless communication system. The results of simulation analysis
show the feasibility and effectiveness of this methodology
Extended warranty of medical equipment subject to imperfect repairs: an approach based on generalized renewal process and Stackelberg game
Authors: de Santana J. , Santiago R. , Moura M , Lins I.
Published: September 2018

Due to its advanced technology, maintenance services of healthcare equipment have been commonly executed by the original
equipment manufacturer (OEM), which can be characterized as a monopolist. In this context, hospitals require high availability of
their equipment at a reasonable servicing cost, whereas OEM aims to maximize its profit by selling extended warranty (EW) services for multiple consumers. The issue of drawing a maintenance contract between OEM and hospitals has already been treated
by adopting a Stackelberg’s game. However, the “as good as new” and “as bad as old” assumptions are usually considered, which
are rather difficult to observe in practice, especially for healthcare institutions and their technology-intensive equipment. Thus,
we here adopt generalized renewal processes (GRP) for modelling imperfect repairs, and we develop a discrete event simulation
method for finding the best strategies of each player: OEM sets the prices for EW and on-demand maintenance that optimize its
profit, while hospitals choose which option they should hire. We also present an application example with real data gathered from
an angiography device, which is used for mapping blood vessels and diagnosing heart diseases.
Male Central Hypogonadism in Paediatrics – the Relevance of Follicle-stimulating Hormone and Sertoli Cell Markers
Authors: Grinspon Romina P , Urrutia Mariela , Rey Rodolfo A
Published: September 2018

The definition of male hypogonadism, used in adult endocrinology, is not fully applicable to paediatrics. A clear understanding of the developmental physiology of the hypothalamic-pituitary-testicular axis is essential for the comprehension of the pathogenesis of hypogonadal states in boys and for the establishment of adequate definitions and classifications in paediatric ages. This is particularly true for central hypogonadism, usually called hypogonadotropic in adults. Because childhood is a period characterised by a physiological state of low gonadotropin and testosterone production, these markers of hypogonadism, typically used in adult endocrinology, are uninformative in the child. This review is focused on the physiological importance of prepubertal Sertoli cell markers – anti-Müllerian hormone (AMH) and inhibin B – and of the intratesticular actions of follicle-stimulating hormone (FSH) and testosterone during early infancy and the first stages of pubertal development. We discuss the role of FSH in regulating the proliferation of Sertoli cells – the main determinant of prepubertal testicular volume – and the secretion of AMH and inhibin B. We also address how intratesticular testosterone concentrations have different effects on the seminiferous tubule function in early infancy and during pubertal development.
Salivary Leptin Level in Young Adult Males and its Association with Anthropometric Measurements, Fat Distribution and Muscle Mass
Authors: Abdalla Mona Mohamed Ibrahim , Choo Soon Siew
Published: September 2018

Aims:1) To assess salivary leptin levels in normal–underweight versus overweight and obese healthy adult males aged 18–25 years old. 2) The relative contribution of anthropometric measurements, fat percentage, fat distribution (visceral versus subcutaneous) and total as well as regional muscle mass in arms, trunk and legs respectively in predicting salivary leptin levels.Methods:A total of 92 adult males were classified into two groups based on their body mass index(BMI):normal–underweight, BMI ≤24.9 kg/m2(n=51); overweight–obese, BMI ≥25 kg/m2(n=41). Anthropometric measurements such as BMI, waist circumference (WC), hip circumference (HC) and waist–hip ratio (WHR) were measured through standardised methods. Fat percentage, visceral fat level, subcutaneous fat and muscle mass (total and regional) were measured using Karada scan bioelectrical impedance method. Fasting saliva samples were collected and used for assessing salivary leptin concentrations using enzyme-linked immunosorbent assay.Results:Statistical analysis of the data showed a significant difference between the two groups in all of the parameters measured except height and salivary leptin levels. Multiple regression analysis showed that HC, WC and WHR were good predictors for salivary leptin levels in normal–underweight group. However, in the overweight–obese group, height was the most important independent variable that could predict salivary leptin levels as a dependent variable.Conclusions:Predictors for salivary leptin levels in adult healthy males are different in normal–underweight subjects from overweight–obese subjects. The most important predictor for salivary leptin levels is HC in normal weight subjects, while it is height in overweight and obese healthy adult males.
Niveles de parathormona y eventos coronarios agudos en pacientes en hemodiálisis. Fresenius Medical Care Riomar. Barranquilla, 2013-2014
Authors: Cediel César , Luna Karen , Pertuz Adolfo , Pérez Lorenzo
Published: September 2018

Objetivo: Determinar los niveles de parathormona (PTH) y eventos coronarios en pacientes sometidos a hemodiálisis en la Institución Fresenius Medical Care Riomar de Barranquilla durante el periodo 2013-2014.

Materiales y Métodos: Se llevó a cabo un estudio descriptivo y retrospectivo, en el que se incluyeron 194 historias clínicas de pacientes atendidos en la Institución centro de estudio mediante muestreo no probabilístico. Se tuvieron en cuenta aspectos científicos y metodológicos que dieran cuenta de la conducta ética durante la investigación.

Resultados: El 60 % de los pacientes pertenecen al género masculino con una edad promedio de 59,8 años (DE+/-16,2). El 27,8 % presentó algún evento coronario y niveles de paratohormona significativamente superiores (p< 0,05) de manera independiente a la mayoría de posibles factores de confusión. Sin embargo, son más frecuentes los eventos coronarios agudos en pacientes con niveles de PTH ≥ a 300 pg/ml no hipertensos, no dislipidémicos y diabéticos, con edades comprendidas entre los 60-79 años y de género masculino.

Conclusión: Existe asociación estadística significativa entre los niveles elevados de parathormona y la incidencia de eventos coronarios, pero se requieren estudios prospectivos que permitan corroborar los hallazgos encontrados en la presente investigación.