bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison between Collocation Method and Chebyshev polynomial Method for Solving Abel Integral Equation
Authors: Mohammed Amina
Published: February 2020

In this paper will be compared between Collocation method and Chebyshev polynomial for solving Abel integral equation . Numerical examples are presented to illustrate the efficiency and accuracy of the proposed methods.
EVOLUCIÓN CLÍNICA Y PATRONES TERAPÉUTICOS EN PACIENTES MAYORES DE 64 AÑOS CON DIAGNÓSTICO DE CÁNCER. INSTITUTO ONCOLÓGICO DE PANAMÁ. AÑO 2012.
Authors: Botello González Clarissa
Published: February 2020

Debido al envejecimiento demográfico, el número de adultos mayores con cáncer ha incrementado enormemente. Existe escasez de información sobre las características demográficas, la evolución clínica, la supervivencia y los patrones terapéuticos establecidos en los pacientes adultos mayores con cáncer en Panamá. El objetivo de esta investigación era describir la evolución clínica y los patrones de tratamiento efectuados en los pacientes mayores de 64 años con diagnóstico de cáncer, admitidos al Instituto Oncológico Nacional de Panamá durante el año 2012. La información fue obtenida, previo muestreo no probabilístico por conveniencia, de los expedientes clínicos que reposaban en el Departamento de Registros Médicos de dicho hospital. Se trata de un estudio descriptivo longitudinal retrospectivo compuesto por un total de 343 pacientes, de los cuales el 51 % eran mujeres, el promedio de edad fue de 75.3 ± 7. El cáncer de próstata resultó ser el más común. La comorbilidad más frecuentemente observada fue hipertensión arterial y se evidenció poca comorbilidad asociada a cada caso. En la mayoría de los expedientes, no fue constatada ninguna escala de evaluación funcional inicial de los pacientes. Al 71 % del total de los pacientes se les ofrece inicialmente un tratamiento con intento curativo; y de éstos, el 5.7 % de los pacientes llegan a requerir, finalmente, manejo paliativo exclusivo. La evolución, en general, era subjetivamente buena, con poca toxicidad asociada y la mayoría completó tratamiento satisfactoriamente.
REPORTE DE UN CASO, ENFERMEDAD CELÍACA EN PACIENTE CON SÍNDROME DE DOWN
Authors: Bruderer González Elisabeth , Sánchez Juarez Noris , Marín Sánchez Michael
Published: February 2020

La enfermedad celíaca cursa con sintomatología variable, dificultando su diagnóstico clínico, reto que se agrava ante un paciente con Síndrome de Down. Un diagnóstico temprano y adherencia al tratamiento, permitirán mejorar la calidad de vida de estos pacientes, evitando complicaciones nutricionales, metabólicas y neoplásicas. 

Masculino de 47 años, con Síndrome de Down; presenta desde hace un año, dolor abdominal difuso y estreñimiento. Evidencia signos de desnutrición clínica; ante la sospecha de celiaquía se realizan pruebas serológicas, resultando positivas. Confirmamos el diagnóstico mediante endoscopia y biopsia. Se instauró dieta libre de gluten, con mejoría sintomática. 

La enfermedad celíaca posee un espectro de síntomas gastrointestinales, que van desde la diarrea crónica y síntomas de malabsorción, a constipación. Su epidemiología varía regionalmente, y la incidencia aumenta en pacientes con Trisomía XXI.  Dada la clínica inespecífica, las pruebas serológicas cobran importancia en el diagnóstico de esta patología.
POLITRAUMATISMO POR CAÍDA LIBRE, REPORTE DE UN CASO
Authors: Chen Tejada Alex
Published: February 2020

Las lesiones causadas por caída libre son una de las principales causas de trauma en todos los países y tienden a mostrar patrón único en comparaciones con otros accidentes. Los pacientes que sobreviven a la caída libre tienden a sufrir varias lesiones, aquello recibe el nombre de politraumatismo por caída libre. Yo presento un caso de un pintor que cayó desde un techo de 3 pisos de altura. El paciente sufrió varias lesiones secundario a la caída: hematoma epidural derecho pequeño, fractura lineal no deprimida del cráneo, hematoma periocular derecho, contusión pulmonar izquierda leve,  y un neumotórax menor del 5%. El paciente recibió manitol y fenitoína por 48 horas para tratar el trauma craneoencefálico y prevenir convulsiones respectivamente. El hematoma epidural derecho y fracturas faciales se manejaron de forma conservadora (no operativo). El hematoma periocular derecho disminuyó, permitiendo la apertura ocular derecha; el servicio de oftalmología evaluó al paciente y descartó déficits visuales en el  paciente secundario a la caída. Se le da egreso al paciente con resolución del dolor, y sin déficits neurológicos motor o sensitivo.
Tecnologias da informação e comunicação no processo ensino e aprendizagem
Authors: Oliveira Cássia Cristina de
Published: February 2020

O artigo tem o intuito de discorrer sobre o uso das novas tecnologias da informação e comunicação na prática docente. Para isso, foi realizado um levantamento bibliográfico sobre as tecnologias da informação e comunicação no processo de ensino aprendizagem no qual foi possível obter informações sobre o conhecimento, utilização e contribuição das tecnologias na prática pedagógica. A metodologia adotada nessa pesquisa é a revisão da literatura. A ação educativa, com o envolvimento das TIC’s, poderá ser desenvolvida na perspectiva de promover a experimentação, a descoberta e a construção de aprendizagem significativa. A mediação do processo de ensino aprendizagem com o uso dessas ferramentas requer uma avaliação tanto do processo quanto do resultado. A escola não está alheia à sociedade, mas  imersa nela e, assim, é influenciada  o tempo todo pelas modificações ocorridas em todas as esferas. As tecnologias de informação (TIC’s) são relevantes para o processo de ensino-aprendizagem, e seu uso de maneira crítica e criativa possibilita o desenvolvimento do estudante. Porém,  para que isso realmente aconteça são necessárias competências e habilidades tecnológicas e pedagógicas do docente para mediar a construção do conhecimento.
PERSPECTIVA TERAPÊUTICA DA PEDAGOGIA DO OPRIMIDO DE PAULO FREIRE: uma leitura fenomenológico-existencialista
Authors: Almeida Raisa Grasiele Rodrigues de , Rufino Emmanoel de Almeida
Published: February 2020

Neste estudo, acolhemos as leituras freirianas sobre o fenômeno educacional transpondo-as metaforicamente ao setting terapêutico, por considerarmos que há certa similaridade entre esses espaços de formação do ser: formal ou informalmente, ambos são ambientes de ensino-aprendizagem. As reflexões que Paulo Freire desenvolve na obra Pedagogia do oprimido nos apontam prismas provocadores e pertinentes à experiência terapêutica que floresce entre psicólogos(as) e clientes e, conforme pretendemos evidenciar neste estudo, dialogam coerentemente com uma abordagem – em especial – na área da psicologia: a abordagem centrada na pessoa (ACP) de viés fenomenológico-existencialista. Diante disso, a problemática que guia este estudo assim se revela: como a obra Pedagogia do oprimido pode nos ajudar a pensar experiências terapêuticas num viés fenomenológico-existencialistas? As discussões desenvolvidas nos levam a uma compreensão mais apurada a respeito do horizonte de ação/atuação dos profissionais da educação e da psicologia nos seus ambientes terapêuticos. Dentre as muitas conclusões a que nos apontam a presente investigação, destacamos a importância da construção intersubjetiva de interações dialógicas vertidas à promoção emancipatória de si e do outro, cenário que, dentre outras coisas, pretere relações de opressão por considerar que todos os envolvidos em settings terapêuticos e em salas de aula têm algo a aprender com o outro.
Learning is negatively associated with strength of left/right paw preference in wild grey squirrels (Sciurus carolinensis)
Authors: Leaver Lisa A. , Ford Steph , Miller Christopher W. , Yeo Matilda K. , Fawcett Tim W.
Published: February 2020

Cerebral laterality, via hemispheric specialisation, has been evidenced across the animal kingdom and linked to cognitive performance in a number of species. Previously it has been suggested that cognitive processing is more efficient in brains with stronger hemispheric differences in processing, which may be the key fitness benefit driving the evolution of laterality. However, evidence supporting a positive association between cognitive performance and lateralization is mixed: data from studies of fish and birds show a positive relationship whereas more limited data from studies of mammals suggest a weak or even negative relationship, suggesting the intriguing possibility of a mammal/non-mammal divide in the nature of this relationship. Here, we report an empirical test examining the relationship between lateralization and cognitive performance in wild grey squirrels (Sciurus carolinensis) by measuring left/right paw preference as a behavioural assay of cerebral lateralization and learning speed as an assay of cognitive efficiency. We carried out a motor-based laterality test using a reaching paradigm and measured learning speed on a problem-solving task. In accordance with the suggestion of a mammal/non-mammal divide, we found a negative relationship between strength of paw preference and performance on the learning task. We discuss this finding in light of niche-specific adaptations, task-specific demands and cognitive flexibility.
Tracking of unpredictable moving stimuli by pigeons
Authors: Wilkinson Anna , Kirkpatrick Kimberly
Published: February 2020

Despite being observed throughout the animal kingdom, catching a moving object is a complex task and little is known about the mechanisms that underlie this behavior in non-human animals. Three experiments examined the role of prediction in capture of a moving object by pigeons. In Experiment 1, a stimulus moved in a linear trajectory, but sometimes made an unexpected 90oturn. The sudden turn had only a modest effect on capture and error location, and the analyses suggested that the birds had adjusted their tracking to the novel motion. In Experiment 2, the role of visual input during a turn was tested by inserting disappearances (either 1.5 cm or 4.5 cm) on both the straight and turn trials. The addition of the disappearance had little effect on capture success, but delayed capture location with the larger disappearance leading to greater delay. Error analyses indicated that the birds adapted to the post-turn, post-disappearance motion. Experiment 3 tested the role of visual input when the motion disappeared behind an occluder and emerged in either a straight line or at a 90oangle. The occluder produced a disruption in capture success but did not delay capture. Error analyses indicated that the birds did not adjust their tracking to the new motion on turn trials following occlusion. The combined results indicate that pigeons can anticipate the future position of a stimulus, and can adapt to sudden, unpredictable changes in motion but do so better after a disappearance than after an occlusion.
An Extreme X-Ray Variability Event of a Weak-line Quasar
Authors: Ni Q. , Brandt W. N. , Yi W. , Luo B. , Timlin J. D. , Hall P. B. , Liu Hezhen , Plotkin R. M. , Shemmer O. , Vito F. , Wu Jianfeng
Published: February 2020

We report the discovery of an extreme X-ray flux rise (by a factor of ≳20) of the weak-line quasar Sloan Digital Sky Survey (SDSS) J153913.47+395423.4 (hereafter SDSS J1539+3954) at z = 1.935. SDSS J1539+3954 is the most-luminous object among radio-quiet type 1 active galactic nuclei (AGNs) where such dramatic X-ray variability has been observed. Before the X-ray flux rise, SDSS J1539+3954 appeared X-ray weak compared with the expectation from its ultraviolet (UV) flux; after the rise, the ratio of its X-ray flux and UV flux is consistent with the majority of the AGN population. We also present a contemporaneous HET spectrum of SDSS J1539+3954, which demonstrates that its UV continuum level remains generally unchanged despite the dramatic increase in the X-ray flux, and its C iv emission line remains weak. The dramatic change only observed in the X-ray flux is consistent with a shielding model, where a thick inner accretion disk can block our line of sight to the central X-ray source. This thick inner accretion disk can also block the nuclear ionizing photons from reaching the high-ionization broad emission-line region, so that weak high-ionization emission lines are observed. Under this scenario, the extreme X-ray variability event may be caused by slight variations in the thickness of the disk. This event might also be explained by gravitational light-bending effects in a reflection model.
Identification of QPO Frequency of GRS 1915+105 as the Relativistic Dynamic Frequency of a Truncated Accretion Disk
Authors: Misra Ranjeev , Rawat Divya , Yadav J S , Jain Pankaj
Published: February 2020

We have analyzed AstroSat observations of the galactic microquasar system GRS 1915+105, when the system exhibited C-type quasi-periodic oscillations (QPOs) in the frequency range of 3.4–5.4 Hz. The broadband spectra (1–50 keV) obtained simultaneously from the Large Area X-ray Proportional Counter and Soft X-ray Telescope can be well described by a dominant relativistic truncated accretion disk along with thermal Comptonization and reflection. We find that while the QPO frequency depends on the inner radii with a large scatter, a much tighter correlation is obtained when both the inner radii and accretion rate of the disk are taken into account. In fact, the frequency varies just as the dynamic frequency (i.e., the inverse of the sound crossing time) does as predicted decades ago by the relativistic standard accretion disk theory for a black hole with a spin parameter of ∼0.9. We show that this identification has been possible due to the simultaneous broadband spectral coverage with temporal information as obtained from AstroSat.
Cave morphology, microclimate and abundance of five cave predators from the Monte Albo (Sardinia, Italy)
Authors: Lunghi Enrico , Corti Claudia , Mulargia Manuela , Zhao Yahui , Manenti Raoul , Ficetola Gentile Francesco , Veith Michael
Published: February 2020

Systematic data collection on species and their exploited environments is of key importance for conservation studies. Within the less-known environments, the subterranean ones are neither easy to be studied, nor to be explored. Subterranean environments house a wide number of specialised organisms, many of which show high sensitivity to habitat alteration. Despite the undeniable importance to monitor the status of the subterranean biodiversity, standardised methodologies to record biotic and abiotic data in these environments are still not fully adopted, impeding therefore the creation of comparable datasets useful for monitoring the ecological condition in the subterranean environments and for conservation assessment of related species.

In this work we describe a methodology allowing the collection of standardised abiotic and biotic data in subterranean environments. To show this, we created a large dataset including information on environmental features (morphology and microclimate) and abundance of five predators (one salamander, three spiders and one snail) occurring in seven caves of the Monte Albo (Sardinia, Italy), an important biodiversity hotspot. We performed 77 surveys on 5,748 m2 of subterranean environments througout a year, recording 1,695 observations of the five cave predators. The fine-scale data collection adopted in our methodology allowed us to record detailed information related to both morphology and microclimate of the cave inner environment. Furthermore, this method allows us to account for species-imperfect detection when recording presence/abundance data.
Effect of anthropogenic pressure on grasshopper (Orthoptera: Acridomorpha) species diversity in three forests in southern Cameroon
Authors: Oumarou Ngoute Charly , Kekeunou Sévilor , Lecoq Michel , Nzoko Fiemapong Armand Richard , Um Nyobe Philène Corine Aude , Bilong Bilong Charles Félix
Published: February 2020

Grasshoppers are highly diversified in tropical rainforests and considered of both ecological and conservation importance. The population dynamics of central African grasshoppers, however, and the structure of their communities remain poorly studied. We report here on the impact of human activities on the diversity of grasshopper species from three localities in southern Cameroon: Ongot, more anthropized forest; Zamakoe, moderately anthropized forest; and Ngutadjap, less anthropized forest. Data were collected using sweep nets, quadrats, and pitfall traps. We analyzed how pressures from human activities affected the grasshopper species compositions using five statistical methods: (1) two non-parametric estimators for specific richness, (2) abundance, (3) abundance distribution model, (4) α diversity index, and (5) β diversity index. The results showed no significant differences in species richness between the sites (nine species at Zamakoe, seven each at Ongot and Ngutadjap). Among these species, one was specific to Ongot and Zamakoe, while one, two, and three species, respectively, were found only in Ongot, Ngutadjap, and Zamakoe. Abundance and species diversity of grasshoppers increased with anthropogenic pressure on the forests. We noticed a great similarity between the grasshopper communities of the two localities under the greatest anthropogenic pressure (Ongot and Zamakoe) compared to that of the less anthropized locality of Ngutadjap. The most common grasshopper species, Mazea granulosa, was most abundant where deforestation was highest. Species diversity was highest in the more and moderately anthropized forests, and the diversity index showed greater similarity between these two grasshopper communities compared with that of the less anthropized forest. This work enables us to better understand how the parameters of these insect communities reflect the degree of forest degradation in southern Cameroon.
Description of a new, unusual species of Diestostemma Amyot & Serville (Hemiptera, Cicadellidae) from Ecuador
Authors: McKamey Stuart H.
Published: February 2020

Diestostemma bicristatasp. nov., is described from Napo Province, Ecuador. It is unusual for the genus in lacking a visible white powdery covering, having raised, weakly reticulate veins on the forewing, a short metathoracic femur (half length of the metathoracic tibia), and is the only species with a double-crested pronotum.
Utilization of Component-Resolved Diagnosis in Precision Allergology
Authors: Lee Jae-Hyun
Published: February 2020

It is very important to identify the causal allergen of each patient in the diagnosis and treatment of allergic diseases. An experimental method of specific IgE testing for single clinically meaningful antigens is called component resolved diagnosis (CRD). Since the introduction of CRD, many single antigens with clinical significance from animal and plant allergenic source have become known. Bet v 1, the major allergen of white birch pollen, can be an indication marker for allergen-specific immunotherapy if the patient is sensitized. Phl p 1, the group I allergen of timothy grass pollen, is an important marker that suggests that patients are truly sensitized to grass pollen. The major allergen of ragweed pollen, Amb a 1 and Art v 1, which is the major allergen of mugwort pollen, are clinically important to distinguish true sensitization. House dust mites have several clinically useful component allergens. Der p 1 and Der p 2 are the initiation molecules in the molecular spreading of allergic diseases caused by house dust mites. Among food allergens, Ara h 2 from peanut, which is closely related to anaphylaxis among several clinical manifestation of peanut allergy. Tri a 19, well known to omega-5 gliadin is important in patients with wheat-dependent exercise-induced anaphylaxis. It is conceivable that the molecular biological concept of CRD methods should lead to ‘patient-customized treatment’ beyond ‘diagnosis’ in the future. Primary prevention of the allergic diseases will apply, which will conceptually be called ‘allergen immunprophylaxis’. This is the right direction of future precision allergology.
Endoscopic Transpapillary Gallbladder Stenting for Acute Cholecystitis in a Patient with Metastatic Pancreatic Cancer
Authors: Nam So Hye , Baek Seung-Ho , Yoo Dong Ryeol , Choi Su Jin , Lee Joune Seup , Oh Dongwook , Kim Myung-Hwan
Published: February 2020

Percutaneous transhepatic gallbladder drainage is an effective treatment for acute cholecystitis in poor surgical candidates. Endoscopic gallbladder drainage procedures, such as endoscopic ultrasound-guided gallbladder drainage, endoscopic gallbladder stenting, and endoscopic naso-gallbladder drainage, have been used as alternative treatments for acute cholecystitis. These procedures are associated with increased patient comfort and physiologic drainage. We report a case of endoscopic gallbladder stenting for acute cholecystitis in a 62-year-old male undergoing chemotherapy for metastatic pancreatic cancer. After endoscopic gallbladder stenting, the patient’s acute cholecystitis resolved and he was able to undergo scheduled chemotherapy. The inserted double-pigtail plastic stent will be left in situ permanently. The choice of drainage modality for acute cholecystitis will generally be based on resources, patient preferences, local expertise, and clinical context.
Paroxysmal Nocturnal Hemoglobinuria Presenting with Chronic Abdominal Pain and Iron Deficiency Anemia
Authors: Kwon Byung Jin , Kim Hyung Wook , Park Su Bum , Kang Dae Hwan , Choi Cheol Woong , Kim Hyeong Jin , Ko Ji Hwan
Published: February 2020

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disorder of hematopoietic stem cells characterized by chronic intravascular hemolysis, nocturnal hemoglobinuria, thromboembolic events and secondary bone marrow failure caused by uncontrolled complement activation. Generally, chronic abdominal pain and iron deficiency anemia are considered typical symptoms of gastrointestinal diseases, but are also common in PNH. We report a case of PNH presenting with chronic abdominal pain and iron deficiency anemia, along with a relevant literature review.
Pulmonary Disease Related to E-Cigarettes
Authors: Park So-Young
Published: February 2020

The potential role of E-cigarettes in smoking cessation is debatable, and whether they are harmful remains controversial worldwide. However, several cases of E-cigarette or vaping-associated lung injury (EVALI) have been reported in the United States. In this review, we discuss and summarize EVALI cases.
Piriformis Syndrome
Authors: Foster Mark R
Published: February 2020

Abstract

Seven patients underwent release of the piriformis from the femur. Patients with residual symptoms after conservative treatment had dramatic relief of sciatica and 70% resumed customary work after surgery. Minimum followup was 31 montiis (average: 51 months). Early diagnosis can avoid prolonging ineffective empiric treatment and disability with satisfactory results achieved in most patients by conservative treatment and relief of sciatica in selected surgical cases.
Sampling‐Based versus Design‐Based Uncertainty in Regression Analysis
Authors: Abadie Alberto , Athey Susan , Imbens Guido W. , Wooldridge Jeffrey M.
Published: February 2020

Consider a researcher estimating the parameters of a regression function based on data for all 50 states in the United States or on data for all visits to a website. What is the interpretation of the estimated parameters and the standard errors? In practice, researchers typically assume that the sample is randomly drawn from a large population of interest and report standard errors that are designed to capture sampling variation. This is common even in applications where it is difficult to articulate what that population of interest is, and how it differs from the sample. In this article, we explore an alternative approach to inference, which is partly design‐based. In a design‐based setting, the values of some of the regressors can be manipulated, perhaps through a policy intervention. Design‐based uncertainty emanates from lack of knowledge about the values that the regression outcome would have taken under alternative interventions. We derive standard errors that account for design‐based uncertainty instead of, or in addition to, sampling‐based uncertainty. We show that our standard errors in general are smaller than the usual infinite‐population sampling‐based standard errors and provide conditions under which they coincide.
Willpower and compromise effect
Authors: Masatlioglu Yusufcan , Nakajima Daisuke , Ozdenoren Emre
Published: February 2020

This paper provides a behavioral foundation for modeling willpower as a limited cognitive resource that bridges the standard utility maximization and Strotz models. Using the agent's ex ante preferences and ex post choices, we derive a representation that captures key behavioral traits of willpower‐constrained decision making. We use the model to study the pricing problem of a profit‐maximizing monopolist who faces consumers with limited willpower. We show that the optimal contract often consists of three alternatives and that the consumer's choices reflect a form of the “compromise effect,” which is induced endogenously.
Learning by matching
Authors: Chen Yi-Chun , Hu Gaoji
Published: February 2020

This paper studies a stability notion and matching processes in the job market with incomplete information on the workers' side. Each worker is associated with a type, and each firm cares about the type of her employee under a match. Moreover, firms' information structure is described by partitions over possible worker type profiles. With this firm‐specific information, we propose a stability notion which, in addition to requiring individual rationality and no blocking pairs, captures the idea that the absence of rematching conveys no further information. When an allocation is not stable under the status quo information structure, a new pair of an allocation and an information structure will be derived. We show that starting from an arbitrary allocation and an arbitrary information structure, the process of allowing randomly chosen blocking pairs to rematch, accompanied by information updating, will converge with probability one to an allocation that is stable under the updated information structure. Our results are robust with respect to various alternative learning patterns.
Efficient multiunit auctions for normal goods
Authors: Baisa Brian
Published: February 2020

I study multiunit auction design when bidders have private values, multiunit demands, and non‐quasilinear preferences. Without quasilinearity, the Vickrey auction loses its desired incentive and efficiency properties. I give conditions under which we can design a mechanism that retains the Vickrey auction's desirable incentive and efficiency properties: (1) individual rationality, (2) dominant strategy incentive compatibility, and (3) Pareto efficiency. I show that there is a mechanism that retains the desired properties of the Vickrey auction if there are two bidders who have single‐dimensional types. I also present an impossibility theorem that shows that there is no mechanism that satisfies Vickrey's desired properties and weak budget balance when bidders have multidimensional types.
Performance‐maximizing large contests
Authors: Olszewski Wojciech , Siegel Ron
Published: February 2020

Many sales, sports, and research contests are put in place to maximize contestants' performance. We investigate and provide a complete characterization of the prize structures that achieve this objective in settings with many contestants. The contestants may be ex ante asymmetric in their abilities and prize valuations, and there may be complete or incomplete information about these parameters. The prize valuations and performance costs may be linear, concave, or convex. A main novel takeaway is that awarding numerous different prizes whose values gradually decline with contestants' ranking is optimal in the typical case of contestants with convex performance costs and concave prize valuations. This suggests that many real‐world contests can be improved by increasing the number of prizes and making them more heterogeneous. The techniques we develop can also be used to formulate and solve other contest design questions that have so far proven intractable.
Factors Affecting Health Behaviors in Late School-aged Children from Multicultural Families
Authors: Lee Sangmi
Published: February 2020

Purpose: This study was conducted to investigate factors affecting health behaviors in late school-aged children from multicultural families.Methods: This study included 401 children (112 from multicultural families and 289 from non-multicultural backgrounds) in grades 4~6 in 11 elementary schools. Data on health behaviors and related factors (school adjustment, the mother-child relationship, self-efficacy, etc.) were collected from the children using self-reported questionnaires between May and June in 2019. The collected data were analyzed through a univariate analysis and multiple regression analysis.Results: The health behavior score of multicultural children was lower than that of non-multicultural children (t=3.32, p=.001). In multicultural children, school adjustment (β=.55, p<.001), mother-child relationship (β=.25, p=.001), and perceived health status (very healthy=1; β=.19, p=.011) were significant factors affecting their health behavior and explained 47.0% (F=30.93, p<.001) of the variance.Conclusion: Multicultural late school-aged children are at risk to engage in a lower level of health behaviors than their non-multicultural counterparts. More attention should be paid to ways of improving multicultural children’s perceptions of their health status, maternal relationships, and school adjustment in order to promote health behaviors.
Smartphone Use Patterns of Smartphone-dependent Children
Authors: Park Jeong Hye
Published: February 2020

Purpose: The purpose of this study was to identify the smartphone use patterns of smartphone-dependent children.Methods: The study design was a cross-sectional descriptive study. The data were derived from the 2017 survey on smartphone overdependence conducted by the Ministry of Science and ICT and the National Information Society Agency. The study sample was 595 elementary school students identified as being smartphone-dependent. The data were analyzed by frequency, percentage, mean, standard deviation, the independent t-test, the x2 test, the Pearson correlation coefficient, and multiple regression analysis.Results: The frequency of smartphone use was the factor strongly associated with more severe smartphone dependence in participants. Games were the most commonly used application type among participants, regardless of their degree of dependence. More severe smartphone dependence was associated with greater use of applications such as learning and television/video.Conclusion: As smartphone dependence becomes more severe, children tend to use their smartphones more frequently and to use applications that involve solitary play for the purposes of entertainment and pleasure. The findings suggest that the parents should attentively monitor their children’s smartphone use patterns and provide consistent discipline in a way that ensures appropriate smartphone use.
Study on the Effect of Casting Pressure on the Wear
Resistance of Al-Si Alloy Prepared by Squeeze Casting
Authors: Muna Khedier Abbass Muna Khedier Abbass
Published: February 2020

In this research the effect of applied casting pressure at
constant pouring and die preheating temperatures on the
microstructure and wear resistance of the squeeze cast Al-Si alloy was
investigated. The results showed a refinement in the microstructure
with increasing of the squeeze pressure. The results also showed that
the density of the specimens decreased with application of a 7.5 MPa
applied pressure, but it increased steadily for higher pressures up to 53
MPa. Increasing the squeeze pressure resulted in increasing the
hardness and decreasing the wear rate. These results were explained
based on the densification mechanism brought about by the
application of pressure during solidification.
Influence of Tread Width of the Brake Pedal Pads on the
Friction Coefficient Generated by Bare Foot and
Footwear Soles
Authors: Al-Osaimy A. S. Al-Osaimy A. S.
Published: February 2020

The present work discusses the effect of the treads width of
the rubber brake pedal pads on the friction coefficient. Measurement
of friction coefficient generated by bare foot and rubber footwear
soles sliding against the brake pedal pads of different treads width in
dry, sand contaminated, water and oil lubricated conditions is
discussed.
Experiments of the sliding of bare foot against the rubber
pedal pad showed that friction coefficient of dry sliding significantly
decreased with increasing tread width. The sliding direction has no
effect on the friction coefficient for the tested pads. In the presence of
sand particles separating the two contact surfaces, load had no
influence on friction coefficient. Friction coefficient slightly decreased
with increasing tread width. For water wetted pedal pad, friction
coefficient displayed higher values than that observed for the
condition of presence of sand particles. Friction values showed
consistent trend with increasing the tread width. Friction displayed by
oil lubricated pedal pads was the lowest and the sliding condition
could be considered as unsafe.
Physical Fitness and Psychological Wellness of Saudi
Engineering Students as Related to Academic Achievement
Authors: Abdullah O. Bafail Abdullah O. Bafail
Published: February 2020

The present study was conducted on a stratified random
sample of 100 students of the College of Engineering of King
Abdulaziz University (KAU), representing the Saudi university
students, with the objectives of: (a) studying the impact of students'
physical fitness and psychological wellness on their academic
achievement, (b) identifying effective related factors improving or
limiting students' achievement and, (c) presenting a practical model of
optimal physical fitness and psychological wellness for Saudi
students. Data of the study are needed by the planners in the Kingdom
of Saudi Arabia (KSA) to harmonize and optimize the presented
services related to the educational process, and to have utmost output
of them.
Each of the selected students was interviewed for his health
and psychological status, performed intelligence test and subjected to
fit-test measurements, followed by testing his academic records and
recording his Grade Points Average (GPA).
Analysis of variance for the effect of the tested students' 57
variables on their GPAs revealed highlighting 20 of them as the most
influential variables, and further testing the significance of their
effects indicated that the main academic effective factors on students’
academic achievement include: students' levels of intelligence and the
student's background education of the holy Quran, English language
and computer practices; meanwhile, the "relatively exceeding"
numbers of courses attended by students through the academic
semester have a negative impact on their GPAs. The need of the
students for the university stipend represents the main studied
economic factor which has impact on their academic achievement.
The main effective cultural, social and health factors include: the
students' involvements in community scientific,
تأثير إضافة الزركونيوم والكوبلت على سلوك التآكل والبلي الانزلاقي الجاف لسبيكة "نحاس ألومنيوم نيكل" التي تتذكر شكلها
Authors: عبد الرحيم كاظم عبد علي عبد الرحيم كاظم عبد علي
Published: February 2020

البحث الحالي يتضمن دراسة تأثير إضافة الزركونيوم والكوبلت في السلوك التآكلي والبلي الانزلاقي الجاف للسبيكة (Cu+13%Al+3.8%Ni) التي تتذكر شكلها. تمت دراسة اختبار التآكل باستخدام طريقة استكمال منحنى تافل ووسط التآكل المستخدم هو المحلول الملحي (3.5NaCl). وتمت دراسة اختبار البلي الانزلاقي الجاف باستخدام الترتيب المسماري إلى القرص. كما تمت دراسة السبيكة بحالات مختلفة: السبيكة بعد المعاملة المحلولية والإخماد، والسبيكة بعد إضافة الزركونيوم بنسب مختلفة (0.4,0.8 and 1.2wt% Zr)، والسبيكة بعد إضافة الكوبلت بنسب مختلفة (0.4,0.8 and 1.2wt% Co) تم تحضير جميع السبائك بنفس الأسلوب وباستخدام ميتالورجيا المساحيق.أظهرت نتائج التآكل أن زيادة نسبة الزركونيوم والكوبلت عملت على زيادة معدل التآكل في الوسط الملحي. كذلك أظهرت نتائج اختبار البلي الانزلاقي الجاف أن زيادة نسبة الزركونيوم والكوبلت المضافة عملت على زيادة مقاومة السبيكة للبلي الانزلاقي الجاف.
تتبع الحركة القلبية في صور الرنين المغنطيسي باستخدام طريقة تسجيل الصور اللاخطي
Authors: رنـا حـدّاد رنـا حـدّاد
Published: February 2020

إن عملية تتبع حركة القلب تساعد الطبيب على تحديد مكان الإصابة الفعلي في العضلة القلبية لمرض ما كالاحتشاء القلبي، وعلى درجة أو نسبة الخطورة الحاصلة للمنطقة المصابة من القلب. لذا فإنه في هذا البحث تم تجريب وتطبيق ثلاث تقنيات مختلفة للتسجيل اللاخطي على الصور القلبية المحصلة بطريقة الرنين المغنطيسي من أجل تتبع حركة القلب والتي تعتبر سريعة وذات سعة صغيرة. أولى هذه التقنيات يعتمد على تطبيق خوارزمية ديمون المرتكزة على مبدأ التمويه البصري، وثانيها تعتمد على تطبيق نقاط تحكم باستخدام طريقة العناصر المنتهية لتتبع مكان تغير إزاحة هذه النقاط، أما ثالث هذه التقنيات فيعتمد على طريقة سبلاين ب (شرائح ب) وحساب الإزاحة بواسطة تحريك الأشكال الحرة. ولقد اعتمدنا على حساب مجموع الفرق التربيعي كمعيار تشابه في طرق التسجيل المذكورة لحساب الإزاحات للحركة القلبية حيث يستخدم في حالات التسجيل لصور من نوع واحد وفي حال وجود ضجيج ضبابي، كما هو الحال في صور الرنين المغنطيسي. ولقد تبين أن التسجيل المعتمد على طريقة سبلاين ب أعطى أفضل النتائج في تتبع الحركة القلبية، ويمكن استخدامه بكفاءة لتسجيل صور الرنين المغنطيسي للقلب، وبالتالي احتساب حركة القلب.
Simulation of Cryptographic Algorithms in IPSec on Ad-Hoc Networks
Authors: A.A. Adas A.A. Adas
Published: February 2020

This paper focuses on secure data communication between nodes in Ad-Hoc networks by employing IPSec (Internet
Protocol Security). In wireless communication, Ad-Hoc network is a new paradigm since, which is used for highly sensitive and
emergency operations. Ad-Hoc network is considered a number of mobile nodes that are connected through wireless interfaces and
moves arbitrarily. Ensuring security is one of the main issues due to its infrastructure less solutions. This research aims for IPSec
protocol that provides security for an Ad-Hoc networking in a various applications. IPSec incorporates security model, i.e. AES
(Advanced Encryption Standard) into its framework. In this work, we consider the problem of incorporating security mechanisms to
securing data communication for Ad-Hoc networks. We look at AODV routing protocol (Ad-Hoc On-Demand Distance Vector) in
detail and it is used for secure routing. Simulation of IPSec protocol is simulated using NS-3 simulator. Results from NS-3 simulator
is compared with AH, ESP, and AES in terms of Quality of Service parameters throughput, average processing time and average
end-to-end delay.
التنبؤ بتأخيرات الحركة في شبكات المقاسم الهاتفية باستخدام نماذج مختلفة من الشبكات العصبونية
Authors: يحيى فريــد يحيى فريــد
Published: February 2020

. تعتبر التأخيرات مشكلة أساسية في شبكات المقاسم الهاتفية، وإحدى أهم العوامل التي تؤثر بشكل مباشر على جودة الخدمة، إذ إن ازدياد كميات الحركة المنقولة في هذه الشبكات نتيجة ازدياد الخدمات والتطبيقات أدى إلى ظهور التأخيرات بشكل متزايد. استهدف البحث بشكل رئيس عملية التنبؤ بحالات الذروة للتأخيرات الحاصلة في المقاسم الهاتفية باستخدام نماذج مختلفة من الشبكات العصبونية الاستاتيكية والديناميكية، حيث تم اختبار خوارزميات تعليم مختلفة. وأظهرت النتائج تفوق شبكات ناركس (NARX) الديناميكية بشكل واضح. كما أظهرت النتائج تفوقًا واضحًا لخوارزمية ليفنبرج-ماركوارت (LM) من أجل مختلف النماذج المستخدمة. تم اختيار مدينة حلب لتكون حالة دراسية لهذا البحث.
استخدام نظم المعلومات الجغرافية في تقييم مستويات الضوضاء المرورية في مدينة غزة - فلسطين
Authors: علاء الدين داود الجماصي علاء الدين داود الجماصي
Published: February 2020

إن ظاهرة التلوث البيئي من أهم المشكلات التي تهدد عالمنا نظرًا لعلاقته المباشرة بالنشاط البشري. ومن أهم هذه الملوثات هو ما يعرف بالتلوث الضوضائي الذي يعد من الملوثات التي أصبحت تزداد بشكل متسارع في قطاع غزة. وذلك ارتباطًا بعدة عوامل ومؤثرات مختلفة، ذات علاقة بالتلوث إما بشكل مباشر أو غير مباشر. حيث لوحظ أن من أهم هذه المؤثرات هو الازدحام المروري على الطرق. تركزت هذه الدراسة في أحد أجزاء مدينة غزة الأكثر ازدحاما بالمركبات في الشوارع الخمسة الرئيسة الداخلية (عمر المختار والوحدة وجمال عبد الناصر والجلاء والنصر)، علمًا أن الطرق في المدينة هي الوسيلة الوحيدة للمواصلات داخلها وخارجها، وهذا ما أدى إلى تفاقم المشكلة وانعكاس آثارها سلبًا على البيئة والمجتمع المحيط بها. هدفت الدراسة إلى استخدام تقنية نظم المعلومات الجغرافية ، في عمل دراسة تحليلية دقيقة لطبيعة انتشار ظاهرة الضوضاء المرورية ونمذجتها رقميا لتقدير آثارها على السكان والبيئة المحيطة بها، من خلال أهم أحد برمجيات نظم المعلومات الجغرافية (برنامج ArcGIS 9.3). كما ارتكزت منهجية البحث التطبيقية في الحصول على مستويات الضوضاء الحقيقية بالديسيبل dBA، من خلال جهاز Auto range Digital Multi meter بعد أن تم تحديد أماكنها جغرافيا، باستخدام جهاز GPS، وذلك خلال فترتي الذروة من اليوم (الصباح والظهيرة) في يوم عمل وكذلك في يوم إجازة، حيث تقل نسب هذه القيم ليلًا بمقدار 25? تقريبًا. كانت النتائج في المدينة تعكس تأثيرًا خطيرًا لهذه الظاهرة، حيث وصلت أعلى قيمة للضوضاء المرورية في النهار في أغلب الشوارع إلى 91dBA في ظهيرة يوم عمل، وأقل قيمة وصلت إلى 40dBA في صباح يوم إجازة. كما تم تصنيف الطرق الخمسة الرئيسة ومنطقة الدراسة على أساس انتشار الضوضاء فيها، فكان قرابة40? من مساحة المنطقة تتعرض إلى ضوضاء مرورية أكثر من 75dBA في أيام العمل، و9? من مساحة المنطقة تتعرض إلى درجة الضوضاء المرورية نفسها في أيام الإجازات، كما لوحظ أن هذه القيم انعكست سلبا على كل ما يحيط بها، حيث إن 98.6? من سكان منطقة الدراسة يتعرضون في النهار إلى ضوضاء أعلى من المعدل الطبيعي الذي توصي به منظمة الصحة العالمية (55dBA نهارا).
Entrepreneurship and Saudi Engineering Students: Intentions and
Competencies
Authors: Hemaid Alsulami Hemaid Alsulami
Published: February 2020

In recent years, entrepreneurship has opened many doors and opportunities for
individuals and societies alike. In the case of Saudi Arabia, it could reduce the reliance on oil and
contribute to the economy diversification. This research paper aims to investigating students’
entrepreneurial intentions such as their level of interest, the time preference of starting their
venture and preferences regarding a partnership. Further, it assesses the students' attainment level
of skills that are deemed necessary for an entrepreneur to be successful. The research is also
evaluating whether a university has any role in providing the students with the necessary skills
and in which ways it does that. A survey was used to find answers to the research questions and
was distributed to students in different regions of Saudi Arabia. The study found that about 80%
of engineering students are interested in having an entrepreneurial career and the primary
motivator behind this decision is to make more money than what is provide by a traditional job.
Additionally, the majority of students prefer working for a few years before venturing on their
own. The results show that skills and competencies such as decision making, effective
communication, strategic and analytical thinking, flexibility and leadership were acquired at a
better level than skills and competencies such as business acumen, risk taking, financial expertise
and time management. Moreover, only 47% of participants believe that higher education schools
have a role in equipping the students with the required skills, and the majority of those believe the
university has helped them in attaining skills, such as project management skills through business
administration courses.
Observationally constrained modeling of atmospheric oxidation capacity and photochemical reactivity in Shanghai, China
Authors: Zhu Jian , Wang Shanshan , Wang Hongli , Jing Shengao , Lou Shengrong , Saiz-Lopez Alfonso , Zhou Bin
Published: February 2020

Abstract. An observation-based model coupled to the Master Chemical Mechanism (V3.3.1)
and constrained by a full suite of observations was developed to study
atmospheric oxidation capacity (AOC), OH reactivity, OH chain length and
HOx (=OH+HO2) budget for three different ozone (O3)
concentration levels in Shanghai, China. Five months of observations from 1 May to 30 September 2018 showed that the air quality level is lightly
polluted or worse (Ambient Air Quality Index, AQI, of > 100) for
12 d, of which ozone is the primary pollutant for 10 d, indicating
ozone pollution was the main air quality challenge in Shanghai during
summer of 2018. The levels of ozone and its precursors, as well as
meteorological parameters, revealed the significant differences among
different ozone levels, indicating that the high level of precursors is the
precondition of ozone pollution, and strong radiation is an essential
driving force. By increasing the input JNO2 value by 40 %, the
simulated O3 level increased by 30 %–40 % correspondingly under the
same level of precursors. The simulation results show that AOC, dominated by
reactions involving OH radicals during the daytime, has a positive
correlation with ozone levels. The reactions with non-methane volatile
organic compounds (NMVOCs; 30 %–36 %), carbon monoxide (CO; 26 %–31 %) and nitrogen dioxide (NO2; 21 %–29 %) dominated
the OH reactivity under different ozone levels in Shanghai. Among the
NMVOCs, alkenes and oxygenated VOCs (OVOCs) played a key role in OH
reactivity, defined as the inverse of the OH lifetime. A longer OH chain
length was found in clean conditions primarily due to low NO2 in the
atmosphere. The high level of radical precursors (e.g., O3, HONO and
OVOCs) promotes the production and cycling of HOx, and the daytime
HOx primary source shifted from HONO photolysis in the morning to
O3 photolysis in the afternoon. For the sinks of radicals, the reaction
with NO2 dominated radical termination during the morning rush hour,
while the reactions of radical–radical also contributed to the sinks of
HOx in the afternoon. Furthermore, the top four species contributing to
ozone formation potential (OFP) were HCHO, toluene, ethylene and
m/p-xylene. The concentration ratio (∼23 %) of these four
species to total NMVOCs is not proportional to their contribution
(∼55 %) to OFP, implying that controlling key VOC species
emission is more effective than limiting the total concentration of VOC in
preventing and controlling ozone pollution.
Chemical loss processes of isocyanic acid, HNCO, in the atmosphere
Authors: Rosanka Simon , Vu Giang H. T. , Nguyen Hue M. T. , Pham Tien V. , Javed Umar , Taraborrelli Domenico , Vereecken Luc
Published: February 2020

Abstract. The impact of chemical loss processes of isocyanic acid was studied by a combined theoretical and modeling study. The potential energy surfaces of the reactions of HNCO with OH and NO3 radicals, Cl atoms, and ozone, were studied using high-level CCSD(T)/CBS(DTQ)//M06-2X/aug-cc-pVTZ quantum chemical methodologies, followed by TST theoretical kinetic predictions of the rate coefficients at temperatures of 200–3000 K. It was found that the reactions are all slow in atmospheric conditions, with k(300 K) ≤ 7 × 10−16 cm3 molecule−1 s−1; the predictions are in good agreement with earlier experimental work, where available. The reverse reactions of NCO radicals, of importance mostly in combustion, were also examined briefly. The global model confirms that gas phase chemical loss of HNCO is a negligible process, contributing less than 1 %. Removal of HNCO by clouds and precipitation is a larger sink, contributing for about 10 % of the total loss, while globally dry deposition is the main sink, accounting for ~ 90 %. The global simulation also shows that due to its long chemical lifetime in the free troposphere, HNCO can be efficiently transported into the UTLS by deep convection events. Average daily concentrations of HNCO are found to rarely exceed levels considered potentially toxic, though locally instantaneous toxic levels are expected.the free troposphere, HNCO can be efficiently transported into the UTLS by deep convection events. Average daily concentrations of HNCO are found to rarely exceed levels considered potentially toxic, though locally instantaneous toxic levels are expected.