bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Bacau City�s Antropic Activities on the Heavy Metals Concentration Measured on Bistrita and Siret River Sides
Authors: Chitimus Alexandra-Dana , Nedeff Florin-Marian , Sandu Ion , Radu Cristian , Mosnegutu Emilian , Sandu Ioan Gabriel
Published: February 2020

The main objective of the current research is to determine the content of heavy metals from the Bistrita and Siret River banks, respectively Siret River � in Bridge Holt area, Siret River � canal UHE and Siret River- downstream confluence Bistrita/Siret. The choice of sampling points took into consideration the areas where the pollution sources are located. Established maximum values were not exceeded in the case of mercury in the soil for all three sampling points Siret River � in Bridge Holt area, Siret River � canal UHE and Siret River- downstream confluence Bistrita/Siret. Exceeding values recorded in the sampling points Siret River � in Bridge Holt area, Siret River � canal UHE and Siret River- downstream confluence Bistrita/Siret (for cadmium, nickel and chrome) resulted from discharged residual waters, industrial platforms form Bacau city and the improper storage of municipal waste.
Five Years Retrospective Review of Colorectal Cancer Risk Factors in the Black Sea Coast Population
Authors: Micu Sergiu Ioan , Oraiopoulou Ismini , Manea Madalina Elena , Musat Marilena , Rogoveanu Anca , Dumitru Andrada , Preda Gabriel , Popoiag Roxana
Published: February 2020

Considering its increasing incidence, complications, comorbidities, mortality and last but not least the tendency to decrease the age of onset, colorectal cancer (CRC) represents one of the significant concerns related to oncology diseases becoming in the last decades a public health problem. Although the etiology is not yet completely known, colorectal cancer is considered a disease with multiple factors, an important place occupying the impact of the environmental factors on the genetically particularly predisposition of patients. In order to reduce the incidence of this disease, screening methods have been developed that are addressed primarily to the population at risk and which have contributed significantly to reducing the occurrence of this condition. The purpose of this paper is to evaluate the presence of specific risk factors for CRC in the Black Sea Coast population for a period of 5 years, and to contribute to the reinforcement of some notions already well known in the specialized literature. By publishing this work, the committee of authors hopes to strengthen the profile of the individual at risk of developing CRC in order to identify better those that are in danger of developing this disease and refer them to screenin
Effectiveness of Prevention of Clostridium difficile Infection by Chemical Methods
Authors: Lupu Mary-Nicoleta , Sandu Madalina Nina , Turcanu Roxana , Ariton Cristian
Published: February 2020

Medical assistance-related infections are acquired through medical care and are caused by germs resistant to several antibiotics, requiring specific antibiotherapy. One of these germs is Clostridium difficile, responsible for the occurrence of a large number of cases with diarrheal syndrome lately, increasing the cost of care per patient, morbidity and mortality. One of the methods of fighting is the use of disinfectants.
Primitive Gastric Lymphoma - a Series of 3 Cases
Authors: Voicu Dragos , Volovat Constantin , Volovat Simona Ruxandra , Beznea Adrian , Constantin Bianca , Rebegea Laura , Firescu Dorel , Ciubara Bogdan Alexandru , Mihailov Raul , Constantinescu Dan , Serban Cristina
Published: February 2020

The Primitive Gastric Lymphoma represents the extra-ganglionic non-Hodgkin lymphoma most frequently and comprises a large spectrum, ranging from the mucosa-associated lymphoid tissue (MALT) lymphoma to aggressive diffuse large B-cell lymphoma. The Primitive Gastric Lymphoma is a rare tumor, with an occurrence ranging from 4% to 20% of non-Hodgkin lymphomas and approximatively 5% of primary gastric neoplasms. The chronic gastritis secondary to the infection with Helicobacter pylori was considered a major predisposing factor for MALT lymphoma. The clinical evolution and the prognosis of this disease depend on the subtype and histopathological stage at the moment of the diagnosis. Due to its rarity, many aspects of this neoplasm remain still controversial.
Contribution of Pathology in Surgical Oncology in Malignant Tumors of the Salivary Glands
Authors: Sirbu Ioan , Budacu Cristian Constantin , Volovat Constantin , Danila Vlad , Stefanescu Ovidiu Mihail , Scutariu Mihaela Monica , Volovat Simona Ruxandra , Costan Victor
Published: February 2020

The practice of oncology continues to be an area of continuous renewal. The volume of knowledge in the field of cancer therapy is increasing rapidly compared to any other medical discipline, constraining the need for permanent information. The first data on malignancies are linked to the 11th century BC. The concerns of physicians were attracted to the cancerous disease, the observations and hypotheses regarding it being mentioned in different writings of the time. The increased frequency of cancer in the oro-maxillofacial region is favored by a number of factors: the great diversity of maxillofacial structures and the very important changes in the phylogenesis and ontogeny of these structures; the embryonic existence of the branchial arches, with the possibility of remaining residues in this stage; function of the intense quality of the face region and the oral region, as the first segment of the matter import apparatus; the multitude of irritant factors, which play an important role in the occurrence of cancer ( temperature, food hardness, dust, chemical noxiousness). The improvement of the methods and techniques of the surgical operations performed on the maxillofacial region had a decisive influence on the treatment of this region. In patients whose pathologic (bleeding diathesis, heart disease, liver disease, diabetes, etc.) can lead to various complications (local and general), interventions of oral and maxillofacial surgerycan perform as a preparation prior appropriate. The study includes a sample of 48 patients with malignant tumors of the salivary glands. The treatment of malignant tumors of the salivary gland have to be as wide early and surgically, with radiotherapy and / or multi-agent chemotherapy. Radiotherapy alone is insufficient, indicated only as palliative treatment.
Integration of Fuels Types and Chemical Properties with the Design of the Rocket Engine�s Bell Exhaust Nozzle and Combustion Chamber
Authors: Nae Catalin , Andrei Irina-Carmen , Stroe Gabriela-Liliana , Berbente Sorin
Published: February 2020

The chemical properties of the fuels are crucial for obtaining the numerical accuracy during the design and performance analysis in case of liquid fuel propelled rocket engines, as well as the trajectory optimization. In this paper, the research was primarly focused on optimizing the numerical accuracy for non-linear two-dimensional approximation the Fuel Combustion Charts; secondarily, the investigation was carried on the design of the bell-nozzle of a liquid propelled rocket engine, taking into account the variation of the coefficients which are significant for expressing the fuels chemical properties. From the Fuel Combustion Charts, the authors selected a the LOX - Kerosene combination for propelling the rocket engine, due to the most convenient matching with the technology and material specifications, safety and environmental friendly requirements; from the LOX-Kerosene Charts, the authors have originally developed a method to obtain the expression of a non-linear approximation function of two variables. The design of the bell shaped nozzle and combustion chamber for a liquid propelled rocket engine was included, in purpose to illustrate the link between the LPRE design and the fuels types and chemical properties.
Expression of PIGF and sFLT-1 Biomarkers in Pregnancy Toxaemia
Authors: Mihalceanu Elena , Scripcariu Ioana Sadyre , Lazar Ioan Tudor , Pangal Alexandra , Adam Ana Maria , Bulimar Virgil , Dimitriu Cristina Daniela , Negru Irina
Published: February 2020

Toxaemia is a pathological condition specific to the period of pregnancy which begins and is indissolubly related to the presence of placenta. Antiangiogenic factors, such as sFLT-1 (soluble tyrosine kinase receptor fms-like) and sEng (soluble endoglin) play an important role in the first part of pregnancy. They are linked to physiological vascular neoformation, and, in the second part of the pregnancy, grant the endothelial functionality and physiological vascular remodeling. The aim of the study is to try to establish the levels of the sFLT� 1/PIGF ratio, as a prognostic tool in the patient with pre-eclampsia, depending on the influence of the cumulative risk factors. The sFLT-1 / PIGF report is a potential prognostic parameter in monitoring preeclampsia. The results of our study confirm the importance of deterring these markers for the diagnosis and monitoring of hypertensive pregnancies and at the same time to emphasize that the sFLT-1/PIGF ratio is a good predictor of preeclampsia.
Update on Systemic Therapy for Advanced Soft Tissue Sarcoma
Authors: Smrke A. , Wang Y. , Simmons C.
Published: February 2020

Background: Soft tissue sarcoma (STS) is a rare group of mesenchymal neoplasms which contains over 50 heterogenous subtypes.  There have been great efforts to increase the understanding of treatment of advanced STS (unresectable or metastatic disease). We wished to determine if outcomes for patients with advanced STS have improved over time, and to assess the current evidence for systemic therapy. Methods: We performed a scoping review to evaluate the contemporary evidence for systemic treatment of advanced soft tissue in adults (>18 years old). Phase I, II, and III studies of systemic therapy for advanced STS published in the English language were included. After abstract and full text review of 77 studies, 62 trials met inclusion criteria.  Results: The number of clinical trials conducted and published in advanced STS has increased over the last 30 years. Although median OS has increased, attempts at improving first line therapy through dose intensification, doublet chemotherapy or alternative backbones have not been successful. The optimal therapy beyond anthracyclines remains a challenge, especially given the inherent heterogeneity of grouping multiple STS subtypes within clinical trials. However, increasing numbers of agents are being studied and several studies had shown isolated PFS or OS benefit.  Conclusions: First line anthracycline systemic therapy remains the standard of care for advanced STS.  However, choice of subsequent therapy beyond anthracyclines remains challenging. Novel systemic therapies, using molecular diagnostics to direct therapy, subtype specific trials and learning from real world retrospective data are all important in improving outcomes for patients with advanced STS.
Molecular targets and novel therapeutic avenues in soft tissue sarcoma
Authors: Elkrief A. , Alcindor T.
Published: February 2020

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Tomografía de Internet: Adquisición y Estudio de Parámetros Dinámicos de la Red
Authors: Anderson Ricci Mauricio
Published: February 2020

En este trabajo hemos realizado un estudio de la topología de Internet, mediante lo que se conoce en la bibliografía como Tomografía de Red. Nuestro objetivo estuvo focalizado en la adquisición y análisis de datos que nos permitiesen caracterizar a Internet, tanto a nivel IP como a nivel de router. Para esto hemos desarrollado Magallanes, un software de medición que opera sobre la plataforma PlanetLab y nos permite realizar exploraciones desde monitores distribuidos en todo el planeta.
Modelo de la tensión inducida por un rayo sobre líneas de distribución
Authors: Henao Céspedes Vladimir , Díaz Cadavid Luis Fernando , Fano Walter Gustavo , Cano Plata Eduardo Antonio
Published: February 2020

En este trabajo se han modelado las emisiones electromagnéticas ocasionadas por la descarga de un rayo, considerando al rayo como una antena monopolo corto sobre un plano de tierra perfectamente conductor. Mediante esta analogía se calculan los campos eléctricos y magnéticos radiados, y luego se calcula la tensión inducida en una línea de distribución considerada como un lazo corto. La expresión matemática utilizada para el cálculo de la tensión inducida ya fue propuesta en un trabajo previo y en el presente trabajo es validada mediante su confrontación en un escenario simulado con dos expresiones conocidas para el cálculo de la tensión inducida, una recomendada por la IEEE y desarrollada por S. Rusck y otra desarrollada por Barbosa.  Sobre la base de las consideraciones realizadas por Rusck para la obtención de su expresión para la tensión inducida, la geometría relacionada con la expresión propuesta es adaptada para hacerla comparable con el referente internacional de Rusck en la norma IEEE. Posteriormente se han analizado los comportamientos dV_ind/dy de las tres expresiones en la región de radiación de campo cercano del rayo, determinando que las tendencias (las cuales son de carácter hiperbólico) de la expresión propuesta y la desarrollada por Rusck (estandarizada a nivel internacional en la norma IEEE 1410) presentan una gran similitud cuando los campos radiados sobrepasan los 20 m, dando validez a la expresión propuesta.
Deformaciones de segundo orden en la transmisión de haces y pulsos gaussianos a través de una capa isótropa
Authors: Acosta Eduardo Omar , Álvarez Natalia Clara , Garea Maria Teresa , Perez Liliana , Sorichetti Patricio
Published: February 2020

Las ondas planas monocromáticas permiten describir adecuadamente muchas de las propiedades de la radiación propagada, reflejada y transmitida a través de medios de distintas propiedades ópticas. Sin embargo, algunas características solo aparecen considerando haces y/o pulsos limitados.  En este trabajo determinamos y analizamos algunas características de transmisión de haces (limitados en el espacio) o pulsos (limitados en el tiempo) con distribución gaussiana. Consideraremos que la transmisión se realiza a través de una placa plano-paralela de material isótropo lineal y haciendo una aproximación a segundo orden. En el caso de un haz limitado en el espacio, consideramos que la dirección de onda media es perpendicular a la placa. Si está limitado en el tiempo, consideramos que la incidencia de todas las ondas es normal a la placa. Comparamos los efectos no geométricos para ambos tipos de limitación para los casos en que la placa es absorbente, transparente o con ganancia en condiciones de linealidad.
Loop Antenna Characterization for ELF and SLF Measurements
Authors: Quintana Gonzalo Iñaki , Alonso Ramiro , Fano Walter Gustavo
Published: February 2020

Los campos electromagnéticos que se encuentran presentes en la Tierra, son debidos tanto a emisiones de la naturaleza como producidos por el ser humano. Los campos eléctricos y magnéticos que son generados por eventos naturales como erupciones volcánicas y terremotos, son aspectos de tectomagnetismo, volcanomagnetismo y tectoelectricidad, en el espectro electromagnetico desde las frecuencias de radio (RF) hasta las frecuencias de los submicrohertz. Este trabajo se dedica a la caracterización de antenas lazo para medir los precursores electromagnéticos de movimientos sı́smicos junto con otros efectos naturales en ELF (3-30 Hz) y SLF (30-300 Hz). El factor de antena, la impedancia, el factor de calidad Q y la sensibilidad de las antenas son medidos. Estas caracterı́sticas son de vital importancia para la elección de la antena lazo a utilizar en el marco del proyecto de investigación de UBACyT Estudio de Perturbaciones Electromagnéticas Producidas por Movimientos Sı́smicos.
Fragmentación y Mezcla de redes ad-hoc usando el protocolo ANTop
Authors: Torrado Pablo Damian
Published: February 2020

ANTop (Adjacent Network Topology) es un protocolo distribuido y descentralizado para redes ad-hoc. Está basado en un hipercubo para el espacio de direccionamiento, donde se asegura la adyacencia de las direcciones de los nodos, lo cual permite que protocolos de ruteo glutones encuentren la ruta óptima. Un mecanismo distribuido, que establece una analogı́a entre los nombres reales y las direcciones de red, es implementado usando tablas distribuidas de hash. En este trabajo nosotros estudiamos los problemas de partición y mezcla, con el fin de completar las funcionalidades de ANTop, y proveer una implementación en sistemas Linux.
Simple method to determine the resolution and sensitivity of systems for optoacoustic tomography
Authors: Gonzalez Martin German , Acosta Eduardo Omar , Santiago Guillermo
Published: February 2020

En este trabajo se presenta un método para determinar la resolución espacial y la sensibilidad de sistemas para tomografía optoacústica (TOA). Éste consiste en la obtención de la imagen de una muestra basada en una lámina transparente embebida en agarosa. La lámina posee un determinado patrón realizado con una impresora láser que permite determinar la resolución espacial del sistema. Por otro lado, como su umbral de daño es similar a del tejido vivo, también es posible establecer si el sistema posee la suficiente sensibilidad para ser usado en muestras biológicas. El método es directo, rápido y repetible, y fue probado en un sistema TOA para obtención de imágenes bidimensionales desarrollado en nuestro laboratorio.
Implementación de un Control Activo de Ruido en Configuración Feedback basado en un Microcontrolador
Authors: Bernadí Pablo Tomás , Gomez Pablo
Published: February 2020

Este trabajo describe la implementación de un sistema de control activo de ruido sobre la plataforma EDU-CIAA-NXP con hardware reducido y de bajo costo. Se hace una revisión del algoritmo filtered-X LMS en configuraciones feedforward y feedback, y se detalla el diseño de filtros anti-alias y de reconstrucción. Se describe el software que corre sobre la plataforma, y se muestran resultados de ensayos con la configuración feedback. Usando un tono puro como señal perturbadora se logró una atenuación de 30dB, que es adecuada según requerimientos de performance en aplicaciones de control activo de ruido.
Generación de frentes de onda acústicos cilíndricos a través de parlantes iónicos
Authors: Gomez Pablo , D'onofrio Enrque , Santiago Guillermo Daniel
Published: February 2020

Presentamos la generación de frentes de onda acústicos cilı́ndricos usando transductores iónicos. Estos transductores están basados en la transferencia de momentum lineal por colisiones entre iones generados en una descarga corona y moléculas neutras. Dado que la forma de los electrodos puede ser elegida con gran flexibilidad, es posible obtener un flujo de aire que, en las vecindades del emisor, tiene asociado un frente de onda que se aparta de los conseguidos habitualmente con pistones planos. Mostramos las caracterı́sticas acústicas de un transductor cilı́ndrico y, como aplicación, el uso en el estudio de un filtro pasabanda basado en un cristal sónico.
Modelado y Simulación de una Intersección de Calles en un Contexto Multi-Agente
Authors: Nacht Joaquín , Falco Mariana , Robiolo Gabriela
Published: February 2020

Las pérdidas de tiempo por congestión y embotellamientos de tráfico son sucesos corrientes en las ciudades por una configuración no óptima de los semáforos. Diversas ciencias y especialidades han intentado comprender el fenómeno e identificar las causas en pos de obtener una solución apropiada. El presente trabajo introduce la extensión de un sistema orientado a agentes cuyo fin es reducir el tiempo de espera de los conductores en una intersección de calles; modelando ahora vehículos (autos y taxis), peatones y un semáforo inteligente que evalúa los pesos de los flujos en dos direcciones (X e Y), giro a la izquierda y derecha.  Para lo cual, la validación fue llevada a cabo en seis escenarios posibles, definidos por medio de la variación del flujo de vehículos y peatones, de una frecuencia de giro en 20 y 80 y la aplicación de diferentes factores de ajustes para los semáforos inteligentes. El entorno de simulación se implementó en NetLogo, lo que permitió comparar el impacto del uso del semáforo inteligente versus un semáforo de tiempos fijos. Finalmente, presentaremos las conclusiones y el trabajo futuro.
Circuit Theory Analysis of Acoustically Coupled Rooms
Authors: Miyara Federico
Published: February 2020

Se propone un enfoque circuital basado en flujos de energía para el análisis de espacios acústicamente acoplados. En el mismo se establece una analogía similar a la que se utiliza en el estudio de sistemas térmicos dinámicos en el cual la potencia acústica es análoga a la corriente eléctrica y la densidad de energía acústica es análoga a la tensión. Los volú­menes son equivalentes a capacitores y la absorción sonora es asimilable a una resistencia. A partir de estas analogías se pue­den plantear ecuaciones diferenciales y modelos en transfor­mada de Laplace y obtener tanto soluciones estacionarias o de régimen permanente como transitorias.
Diseño de un autopiloto para pequeños vehículos no tripulados
Authors: Garberoglio Leonardo , Pose Claudio , Mas Ignacio , Giribet Juan Ignacio
Published: February 2020

En este trabajo se presenta el diseño de un autopiloto para pequeños vehículos autónomos. El trabajo está enfocado principalmente en la arquitectura del sistema, pero se presentan también algunos detalles del firmware desarrollado para el autopiloto. En particular, el firmware incluye el paquete rosserial, que permite una conexión simple con ROS (Robot Operating System), resultando beneficioso para diversas aplicaciones.El desarrollo se valida experimentalmente en un vehículo aéreo no tripulado (UAV 1) del tipo multi-rotor y en un vehículo acuático de superficie (ASV 2). Estos vehículos han sido desarrollados por nuestro grupo, y en este trabajo puede encontrarse información sobre estos proyectos, lo cual puede ser de utilidad para los interesados en el desarrollo de UAV o ASV.
Gradiente de retardo temporal y reflexiones en superficies corrugadas
Authors: Lizaso Georgina Alejandra , Dassie Nicolás Casais , Fernández Damián Andrés , Petrosino Jorge
Published: February 2020

Se analizan las reflexiones de ondas acústicas en superficies corrugadas. Para este trabajo se toma como base una propuesta de Yi-Fan Zhu sobre un modelo relativamente sencillo de metasuperficie. Cada ranura de una superficie corrugada puede considerarse análoga a una fuente de un arreglo lineal, mientras que la profundidad de sus hendiduras se relaciona con la fase de cada fuente.  La propuesta original de Zhu toma como parámetro de diseño al gradiente de fase del arreglo. En este trabajo se analizan las ventajas del diseño de superficies a partir del gradiente de retardos temporales. Se presenta además la posibilidad de incorporar breves retardos en todo el patrón de reflexiones de modo independiente al proceso general de diseño.
Individual differences of conflict monitoring and feedback processing during reinforcement learning in a mock forensic context
Authors: Leue Anja , Nieden Katharina , Scheuble Vera , Beauducel André
Published: February 2020

This study investigated individual differences of conflict monitoring (N2 component), feedback processing (feedback negativity component), and reinforcement learning in a discrimination learning task using a mock (fictitious) forensic scenario to set participants in a semantic task context. We investigated individual differences of anxiety-related, impulsivity-related traits and reasoning ability during trial-and-error learning of mock suspect and nonsuspect faces. Thereby, we asked how the differential investment of cognitive-motivational processes facilitates learning in a mock forensic context. As learning can be studied by means of time-on-task effects (i.e., variations of cognitive processes across task blocks), we investigated the differential investment of cognitive-motivational processes block-wise inN= 100 participants. By performing structural equation modeling, we demonstrate that conflict monitoring decreased across task blocks, whereas the percentage of correct responses increased across task blocks. Individuals with higher reasoning scores and higher impulsivity-related traits relied rather on feedback processing (i.e., external indicators) during reinforcement learning. Individuals with higher anxiety-related traits intensified their conflict monitoring throughout the task to learn successfully. Observation by relevant others intensified conflict monitoring more than nonobservation. Our data highlight that individual differences and social context modulate the intensity of information processing in a discrimination learning task using a mock forensic task scenario. We discuss our data with regard to recent cognitive-motivational approaches and in terms of reinforcement learning.
Efficiency and accuracy of visual search develop at different rates from early childhood through early adulthood
Authors: Gil-Gómez de Liaño Beatriz , Quirós-Godoy María , Pérez-Hernández Elena , Wolfe Jeremy M.
Published: February 2020

Most studies of visual search across the life span have focused on classic feature and conjunction searches in which observers search for a fixed, simple shape target among relatively homogeneous distractors over a block of multiple trials. In the present study, we examine a more realistic task in which participants (4 to 25 years-old) look for images of real objects, presented amongst a heterogeneous array of other objects. The target is unique on every trial, unlike in previous developmental studies of visual search. Our new touchscreen-based “Pirate-Treasure” search also allows the testing of younger children within a video-game-like task. With this method, we tested a large sample (n = 293) of typically developing children and young adults. We assessed the developmental course of different search metrics like search efficiency, motor response differences, and accuracy (misses and false-alarm errors). Results show the most rapid time courses in development for accuracy. Search slopes reach the young adult level most slowly. The intercepts of the Reaction Time (RT) × Set Size function are often attributed to nonsearch perceptual and motor components of the task. The intercept time course is intermediate between accuracy and slope. Interestingly, these developmental functions follow time courses proposed in neuropsychological models of executive function development. This suggests that a single, video-game-like search task could be useful in routine assessments of cognitive development.
An advanced structural characterization of templated meso-macroporous carbon monoliths by small- and wide-angle scattering techniques
Authors: Badaczewski Felix M , Loeh Marc O , Pfaff Torben , Wallacher Dirk , Clemens Daniel , Smarsly Bernd M
Published: February 2020

This study is dedicated to link the nanoscale pore space of carbon materials, prepared by hard-templating of meso-macroporous SiO2 monoliths, to the corresponding nanoscale polyaromatic microstructure using two different carbon precursors wthat generally exhibit markedly different carbonization properties, i.e., a graphitizable pitch and a non-graphitizable resin. The micro- and mesoporosity of these monolithic carbon materials was studied by the sorption behavior of a relatively large organic molecule (p-xylene) in comparison to typical gas adsorbates (Ar). In addition, to obtain a detailed view on the nanopore space small-angle neutron scattering (SANS) combined with in situ physisorption was applied, using deuterated p-xylene (DPX) as a contrast-matching agent in the neutron scattering process. The impact of the carbon precursor on the structural order on an atomic scale in terms of size and disorder of the carbon microstructure, on the nanopore structure, and on the template process is analyzed by special evaluation approaches for SANS and wide-angle X-ray scattering (WAXS). The WAXS analysis shows that the pitch-based monolithic material exhibits a more ordered microstructure consisting of larger graphene stacks and similar graphene layer sizes compared to the monolithic resin. Another major finding is the discrepancy in the accessible micro/mesoporosity between Ar and deuterated p-xylene that found for the two different carbon precursors, pitch and resin, which can be regarded as representative carbon precursors in general. These differences essentially indicate that physisorption using probe gases such as Ar or N2 can provide misleading parameters if to be used to appraise the accessibility of the nanoscale pore space.
Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds
Authors: Mzozoyana Vuyisa , van Heerden Fanie R , Grimmer Craig
Published: February 2020

4-(2-Fluorophenyl)-7-methoxycoumarin (6) was synthesized by Pechmann reaction under mild conditions via a three-step reaction. The solution-state 1H NMR spectra of 6 showed a strong intramolecular interaction between F and H5 (JFH = 2.6 Hz) and 13C NMR suggested that this C–F···H–C coupling is a through-space interaction. The 2D 19F-{1H} HOESY and 1H-{19F} 1D experiments were done to confirm this F···H interaction. The single crystal X-ray structure and the DFT-optimized structure showed that the fluorinated phenyl ring favors the orientation with the fluorine atom closer to H5 than H3. The X-ray structure also showed the existence of the intermolecular C–F···H–C interaction.
ENTREPRENEURIAL BUSINESS: GENETIC LOTTERY OR A CHOICE
Authors: Nikolić Slavka , Kovijanić Tijana , Mladenović Marijana , Ćelić Đorđe
Published: February 2020

Research dedicated to entrepreneurship has, from the very beginning, created a gender gap as it was mostly considered to be the masculine one.
Studies with the main focus on psychological characteristics of entrepreneurs are mostly based on a comparison with other professionals, rarely approaching gender
differences. Using the mixture of general personal and entrepreneurial traits, this study investigates entrepreneurial dilemma and answers the question whether
entrepreneurship can or cannot be gendered, using a sample of potential entrepreneurs. Based on the multivariate analysis of variance, this study empirically proves
that there are no statistically significant differences between the genders according to any criteria, except for the criterion of worry, which is more pronounced
in women than in men. This study offers a good basis for the implementation of the existing models in different areas of entrepreneurship research, extending its
understanding from the gender perspective. From the practical point of view, it provides a deeper understanding of entrepreneurial traits that might be critical for
designing support and educational programs for enhancing (female) entrepreneurship.
Open Cluster IC 1369 and Its Vicinity: Multicolor Photometry and Gaia DR2 Astrometry
Authors: Straižys V. , Boyle R. P. , Raudeliūnas S. , Zdanavičius J. , Janusz R. , Macijauskas M. , Lazauskaitė R. , Černis K. , Zdanavičius K. , Maskoliūnas M. , Čepas V. , Kazlauskas A.
Published: February 2020

The open cluster IC 1369, located in Cygnus close to the galactic equator at the 89.°6 longitude, and its vicinity are investigated by applying two-dimensional photometric classification of stars down to V = 19 mag measured in the Vilnius seven-color photometric system. Employing the Gaia DR2 coordinates, parallaxes, and proper motions, 143 cluster members are found having cluster membership probabilities ≥0.75. The hottest stars of the evolved main sequence are of spectral class B9. Distances to the cluster, determined by two methods based on the Gaia parallaxes, are 3280 and 3370 pc with an uncertainty of 400–500 pc. Employing the physical HR diagram with the coordinates

versus

and the Padova isochrones, the cluster age is found to be between 300 and 350 Myr. Among the cluster members we identified six red giants of spectral classes G5–G8 and luminosities II–III, 17 Am stars, one Ap star, and one B5 blue straggler. The extinction shows a steep rise up to ∼2.0 mag at 300–700 pc, caused by the extensions of the dust cloud LDN 970 and the Great Cygnus Rift, and up to ∼2.5 mag at the edge of the Perseus arm at 3.0 kpc. The extinction is almost constant between 0.9 and 2.5 kpc from the Sun. The average extinction of the cluster members is 2.54 mag. A systematic error of color excesses found in the Argonaut calculator results is discussed.
A Radio Molecular Line Search for Evidence of an O-rich Environment Around Binary in Silicate Carbon Stars
Authors: Zhao Zhang , Chen Xi , Ellingsen Simon P. , Sobolev Andrej M. , Xujia Ouyang
Published: February 2020

We report observations of oxygen-rich (O-rich) radio molecular line tracers, including H2CO, H2O, and HCO+ toward 28 silicate carbon stars (SCSs). SCSs are special evolved star systems that consist of a carbon star associated with peculiar O-rich circumstellar material. Absorption in the 6 cm

transition was detected from seven SCSs using the Shanghai 65 m Tianma radio telescope. In order to further investigate their O-rich material, several 3 mm molecular lines including HCO+ and CO were also observed with the Purple Mountain Observatory 13.7 m telescope. Double-peak profiles in some of these lines suggest the possible presence of a companion in the SCS system. A negative association between H2O masers and H2CO absorption was found in our sample of SCSs. The

maser sources may correspond to an earlier evolutionary stage when the circumstellar envelope (CSE) material is O-rich and limited to a compact and denser region. As the star evolves the CSE gradually expands and carbon abundance is enhanced, resulting in the

masers disappearing and H2CO absorption arising.
Multifrequency Study on the Mode Switching of PSR J0614+2229
Authors: Zhang Y. R. , Wang H. G. , Huang X. J. , Chen J. L.
Published: February 2020

The mode switching phenomenon of PSR J0614+2229 was studied using the archived observations at 686, 1369, and 3100 MHz with the Parkes radio telescope that have not been published before, and combining existing observations from the literature. Over a wide frequency range from 327 to 3100 MHz, the pulsar switches between one mode occurring earlier in pulse phase (mode A) and the other mode appearing later in phase (mode B), with a generally frequency-independent phase offset between their profile peaks. The two modes are found to be different in the following aspects. (1) Mode A has a flatter spectrum than mode B, with a difference in the spectral index of about 0.5. This accounts for the phenomenon that the flux ratio between the modes A and B increases with frequency, and mode A becomes stronger than mode B above ∼500 MHz. (2) For mode B, the flux density of the subintegrated profile is anticorrelated with the emission phase, indicating that the emission from earlier phases is relatively stronger than that from later phases; such an anticorrelation is not observed in mode A. (3) The frequency dependence of the FWHM of the two modes are opposite each other; namely, the FWHM of mode A increases with frequency, while that of mode B decreases with frequency. A possible interpretation is suggested: the longitudinal spectral variation across the two beams may be opposites of each other.
Multiphase Gas Flows in the Nearby Seyfert Galaxy ESO428–G014. Paper I
Authors: Feruglio C. , Fabbiano G. , Bischetti M. , Elvis M. , Travascio A. , Fiore F.
Published: February 2020

We present ALMA 230 GHz continuum and CO(2–1) observations of the nearby Compton-thick Seyfert galaxy ESO428–G14, with angular resolution 0.″7 (78 pc). CO(2–1) is distributed in clumpy spiral arms, a lopsided circumnuclear ring (CNR) with ∼200 pc radius, and a transverse gas lane with size <100 pc, which crosses the nucleus and connects the two portions of the CNR. The main CO velocity gradient is consistent with a rotating disk with dynamical mass M
dyn = 5 × 109
M
⊙ within ∼1 kpc. We detect off-plane gas motions with respect to the main disk plane which likely trace a molecular outflow with rate

, along a biconical structure with radius 700 pc. The CO outflow smoothly joins the warm molecular outflow detected in SINFONI/Very Large Telescope data in the central 170 pc, suggesting that the outflow may cool with increasing distance. Our dynamical modeling of the inner 100 pc region suggests a warped disk or bar, and of fast gas streams which may trace an inflow toward the AGN. The inner warped disk overlaps with the most obscured, CT region seen in X-rays. There, we derive a column density

, suggesting that molecular gas may contribute significantly to the AGN obscuration. Most of the hard X-ray emitting nuclear region is deprived of cold molecular gas and shows a CO-cavity. The CO-cavity is filled with warm molecular gas traced by H2, confirming that the 3–6 keV continuum and Fe Kα emission are due to scattering from dense ISM clouds.
Systematics and evolution of the African butterfly genus Mylothris (Lepidoptera, Pieridae)
Authors: Warren-Gash Haydon , Aduse-Poku Kwaku , Murillo-Ramos Leidys , Wahlberg Niklas
Published: February 2020

We study the systematics and evolutionary history of the Afrotropical butterfly genus Mylothris (Lepidoptera: Pieridae) based on six gene regions (COI, EF1a, GAPDH, MDH, RpS5 and wingless). We find that the genus can be placed into five species groups, termed the jacksoni, elodina, rhodope, agathina and hilara groups. Within these species groups, we find that many species show very little genetic differentiation based on the markers we sequenced, suggesting they have undergone rapid and recent speciation. Based on secondary calibrations, we estimate the age of the crown group of Mylothris to be about 16 million years old, but that many of the species level divergences have happened in the Pleistocene. We infer that the clade has its origin in the forests of the Eastern part of Central Africa, and has spread out from there to other regions of Africa.
Status of the burbot (Lota lota L.) in the Lower Danube (Bulgaria) – a species threatened by climate change
Authors: Pandakov Pencho G. , Teofilova Teodora M. , Kodzhabashev Nikolay D.
Published: February 2020

The study provides data on the catch composition, length-weight relationship, age structure, gender structure, growth, maturation, fecundity, distribution and conservation status of the burbot Lota lota (Linnaeus, 1758) in Bulgaria. During six consecutive winters (2008–2014) a total of 395 burbot specimens were caught. The total length and the weight of the specimens ranged from 16 to 51 cm and 29.8 to 1057 g, respectively. Seven age classes were represented (3- to 9-years-old), with 3-, 4-, and 5-years-old most abundant. The maximal life expectancy was estimated as 12 years. Male-female ratio was 1:1. Maturity happens at the age of four at the earliest, valid for both sexes. One-quarter of the fish, older than 5 years were determined as non-reproducing in the particular year. The absolute fecundity varied between 47 462 and 810 236 eggs for females ranging from 5 to 7 years old and from 25.7 to 41.5 cm in length. A dramatic decrease of burbot population was observed in the last two decades. Warming water temperatures of the Danube, together with fragmentation in its tributaries are considered as the major threats affecting the species. Therefore, the burbot in Bulgaria is classified as Endangered.
E-Learning for Society: A Great Potential to Implement Education for All (EFA) Movement in Indonesia
Authors: Abdul Majid Nuur Wachid , Fuada Syifaul
Published: February 2020

UNESCO has designed the education concept through the EFA movement; thus, the SDGs can be achieved optimally. This movement is expected to create quality education that can be reached by all people, mainly to whom live in villages far from big cities. The effort to equalize education must be supported by recent technology, especially since the penetration of technology into various fields had been introduced simultaneously. E-learning has many benefits, and it can support wide-scale learning. The e-learning concept in Indonesia has been adopted through a digital platform, namely Massive Open Online Courses (MOOCs). There are various publications related to e-learning application for formal education, while the discussion of e-learning for non-formal education is still limited and has not much explored. Following are the results of this literature study (1) e-learning is a digital-based learning tool that has been implemented in most of the universities and higher educations; (2) e-learning application for society cannot be realized because there are many problems (such as low technical skill of the society, so they have difficulty in accessing technology and the facilities support have not been distributed well. Hence it can not be reached massively by the society), resulting the technology utilization for training or counseling have not been implemented optimally yet; and (3) MOOCs are part of e-learning that can be employed by everyone, not only for academics but also for the general public, providing various features like formal education.
Reinforcing Public University Student’s Worship Education by Developing and Implementing Mobile-Learning Management System in the ADDIE Instructional Design Model
Authors: Hanafi Yusuf , Murtadho Nurul , Ikhsan M. Alifudin , Diyana Tsania Nur
Published: February 2020

This study aimed to develop and investigate the impact of the implementation of the Mobile-Learning Management System, which we call elektronik Bimbingan Baca al-Qur’an (e-BBQ, a word in the Indonesian Language), in fostering student’s worship. This research was conducted at Universitas Negeri Malang in the odd semester of the 2018-2019 academic year with ADDIE research design. The implementation stage was carried out with a one-group pretest-posttest design. As a result, the e-BBQ developed was in the form of applications and websites with some menus including Al-Qur'an learning, worship, training, and log in instructor. The evaluation by experts, as well as students and instructors showed that the products developed were suitable for use. e-BBQ has a positive effect; the quality of student’s worship increased significantly after participating in learning by utilizing e-BBQ. e-BBQ is considered to be an interesting medium for learning Islamic religion, able to make learning more enjoyable, and raise the student’s learning motivation
The Akeffa Tutor Application: A New Arabic Writing System
Authors: Jamal Amani Tariq , Aljojo Nahla , Al-Ghamdi Morooj Saleh , Hindi Bashayer Abdulhakeem , Al-Ghanmi Mashael Khaled , Al-Jahdali Shaima Yassin , Karam Baraa Mostafa , Abualnaja Talah Fahad
Published: February 2020

This paper shows an application for a new Arabic writing system, named Tala Arabic Writing System for people with visual impairments. As known, the Braille writing system is a way of communication for many people with visual impairment around the world. Among that, people who are using Arabic Braille faced many problems especially with the diacritical marks, which are written as same as the letters. That’s why a girl named Tala Abo-Alnaja invented a new Arabic writing system where letters and diacritical marks are written as geometrical shapes to make learning easier. Anyone who wants to learn and practice the Tala Arabic writing system can. Since this system is still new and an unknown system among people with visual impairments, there is lacking in learning resources. We proposed an application for teaching the Tala Arabic writing system using an external keyboard covered with plastic prominent shapes. This application was developed based on identified functional requirements and usability. The limitation of this application was center around the keyboard and the one platform it can work on (iOS), and some of the additional things like voiceOver, keyboard language, and the device sound, which added more constraints on the application. The satisfying results of the testing that gained from participants with visual impairments approved the success of this application. Akeffa Application is expected to be an effective way of learning due to the amazing feedback it had.
On Landis’ conjecture in the plane for some equations with sign-changing potentials
Authors: Davey Blair
Published: February 2020

In this article, we investigate the quantitative unique continuation properties of real-valued solutions to elliptic equations in the plane. Under a general set of assumptions on the operator, we establish quantitative forms of Landis’ conjecture. Of note, we prove a version of Landis’ conjecture for solutions to

−\Delta u + Vu = 0

, where

V

is a bounded function whose negative part exhibits polynomial decay at infinity. The main mechanism behind the proofs is an order of vanishing estimate in combination with an iteration scheme. To prove the order of vanishing result, we present a new idea for constructing positive multipliers and use it reduce the equation to a Beltrami system. The resulting first-order equation is analyzed using the similarity principle and the Hadamard three-quasi-circle theorem.
Operários e operárias da fábrica a vapor de chapéus de Antônio José Maia & Cia.: gênero, idade, qualificação profissional e nacionalidade. Recife, década de 1880.
Authors: Mac Cord Marcelo
Published: February 2020

Aberta oficialmente em meados de 1882, a fábrica a vapor de chapéus de Antônio José Maia & Cia. tinha proprietários portugueses. Eles foram obrigados por lei a contratar uma cota de aprendizes nacionais e garantir sua subsistência. No bojo dessa exigência, havia o problema da “transição” do trabalho escravo para o livre e os históricos conflitos entre nativos e estrangeiros no mercado de trabalho. No início da operação do empreendimento fabril, a maior parte da mão de obra especializada era portuguesa. Aos pernambucanos e às pernambucanas das mais variadas idades, foram destinados, de uma forma geral, os serviços mais simples e provisórios. Entre os anos de 1882 e 1886, os portugueses foram paulatinamente substituídos por nacionais formados na própria fábrica a vapor de chapéus, barateando custos de produção. Naquele mesmo espaço de tempo, meninas, meninos, moças, rapazes e mulheres adultas, brasileiros contratados como aprendizes, foram os que mais sofreram com a precarização e com a rotatividade nas oficinas da chapelaria. Nosso artigo analisa as complexidades do objeto de estudo por meio dos instrumentos da história social do trabalho.
Zootechnologies
Authors: Vehlken Sebastian ,   Diaphanes AG
Published: February 2020

Swarming has become a fundamental cultural technique related to dynamic processes and an effective metaphor for the collaborative efforts of society. This book examines the media history of swarm research and its significance to current socio-technological processes. It shows that the hype about collective intelligence is based on a reciprocal computerization of biology and biologization of computer science: After decades of painstaking biological observations in the ocean, experiments in aquariums, and mathematical model-making, it was swarms-inspired computer simulation which provided biological researchers with enduring knowledge about animal collectives. At the same time, a turn to biological principles of self-organization made it possible to adapt to unclearly delineated sets of problems and clarify the operation of opaque systems - from logistics to architecture, or from crowd control to robot collectives. As zootechnologies, swarms offer performative, synthetic, and approximate solutions in cases where analytical approaches are doomed to fail.
Visions of Electric Media
Authors: Roberts Ivy
Published: February 2020

Visions of Electric Media is an historical examination into the early history of television, as it was understood during the Victorian and Machine ages. How did the television that we use today develop into a functional technology? What did Victorians expect it to become? How did the 'vision' of television change once viewers could actually see pictures on a screen?

We will journey through the history of 'television': from the first indications of live communications in technology and culture in the late nineteenth century, to the development of electronic televisual systems in the early twentieth century. Along the way, we will investigate the philosophy, folklore, engineering practices, and satires that went into making television a useful medium.