bluuebunny/crossref_metadata_2025 huggingface dataset:
Características y elementos del fenómeno emprendedor en Villavicencio, Colombia
Authors: Pérez Paredes Alfredo , Torres-Flórez Dagoberto , Torralba Flores Amado , Salgado Cifuentes Wilson Fernando
Published: June 2020

El fenómeno emprendedor empresarial en la actualidad alrededor del mundo ha sido analizado por su gran importancia, al promover la creación de nuevas empresas, empleos y contribuyen a un bienestar de la sociedad al resolver una problemática o necesidad, así como a los emprendedores y colaboradores. En la presente investigación se consideró como objeto de estudio a los emprendedores de Villavicencio en Colombia, toda vez que se desea conocer sobre el tema, aunque en esta parte son resultados preliminares ya que se aplicó a una muestra pequeña y se pretende ampliar el número de encuestas. Se tiene como objetivo, indagar cuales son las principales características que tienen los emprendedores en esta ciudad para la generación de nuevas empresas. Para este trabajo se utilizó una encuesta que se aplicó a los emprendedores para identificar sus principales características, el instrumento utilizado se conformó de 12 ítems a 96 personas, encontrándose que en esta ciudad se perciben condiciones para crear empresas y otro aspecto relevante es la percepción del fracaso como parte del proceso emprendedor.
Los impactos de Bogotá sobre Soacha y su importancia frente a la conformación del Área Metropolitana
Authors: Duque-Duque Naidú , Trejos-Ballesteros Johanna Alexandra , Moreno-Obando José Wilmar
Published: June 2020

Por ser la capital de la República Bogotá se ha convertido en la entidad territorial más importante del país. Esto ha conducido a que ejerza una influencia importante sobre el resto de las entidades territoriales, pero en especial sobre los municipios que la rodean. Su influencia en términos sociales, económicos y geográficos ha conducido a fenómenos de conurbación desde la segunda mitad del siglo XX. En la actualidad esa influencia se mantiene y exige la conformación de un área metropolitana, que permita la articulación de la capital con sus vecinos y en particular con el municipio de Soacha. Si bien se trata de un municipio que enfrenta problemáticas de diverso tipo y que podrían constituir una desventaja muchos de estos problemas se derivan de su vecindad con Bogotá.
Para dimensionar el tamaño de estos problemas, en este documento se identificaron tres grandes ámbitos sobre los cuales se debe realizar una intervención coordinada entre Bogotá y Soacha, como son el crecimiento poblacional y las necesidades que se derivan del mismo. Asimismo, se debe lograr una articulación más estrecha en lo referente a la movilidad y los efectos derivados del traslado de empresas que antes se ubicaban en la capital.
Clinical Trial Design and Development Work Group Within the Quantitative Imaging Network
Authors: Jones Ella F. , Buatti John M. , Shu Hui-Kuo , Wahl Richard L. , Kurland Brenda F. , Linden Hannah M. , Mankoff David A. , Rubin Daniel L. , Tata Darrell , Nordstrom Robert J. , Hadjiyski Lubomir , Holdhoff Matthias , Schwartz Lawrence H.
Published: June 2020

The Clinical Trial Design and Development Working Group within the Quantitative Imaging Network focuses on providing support for the development, validation, and harmonization of quantitative imaging (QI) methods and tools for use in cancer clinical trials. In the past 10 years, the Group has been working in several areas to identify challenges and opportunities in clinical trials involving QI and radiation oncology. The Group has been working with Quantitative Imaging Network members and the Quantitative Imaging Biomarkers Alliance leadership to develop guidelines for standardizing the reporting of quantitative imaging. As a validation platform, the Group led a multireader study to test a semi-automated positron emission tomography quantification software. Clinical translation of QI tools cannot be possible without a continuing dialogue with clinical users. This article also highlights the outreach activities extended to cooperative groups and other organizations that promote the use of QI tools to support clinical decisions.
Quantitative Comparison of Prone and Supine PERCIST Measurements in Breast Cancer
Authors: Whisenant Jennifer G. , Williams Jason M. , Kang Hakmook , Arlinghaus Lori R. , Abramson Richard G. , Abramson Vandana G. , Fakhoury Kareem , Chakravarthy A. Bapsi , Yankeelov Thomas E.
Published: June 2020

Positron emission tomography (PET) is typically performed in the supine position. However, breast magnetic resonance imaging (MRI) is performed in prone, as this improves visibility of deep breast tissues. With the emergence of hybrid scanners that integrate molecular information from PET and functional information from MRI, it is of great interest to determine if the prognostic utility of prone PET is equivalent to supine. We compared PERCIST (PET Response Criteria in Solid Tumors) measurements between prone and supine FDG-PET in patients with breast cancer and the effect of orientation on predicting pathologic complete response (pCR). In total, 47 patients were enrolled and received up to 6 cycles of neoadjuvant therapy. Prone and supine FDG-PET were performed at baseline (t0; n = 46), after cycle 1 (t1; n = 1) or 2 (t2; n = 10), or after all neoadjuvant therapy (t3; n = 19). FDG uptake was quantified by maximum and peak standardized uptake value (SUV) with and without normalization to lean body mass; that is, SUVmax, SUVpeak, SULmax, and SULpeak. PERCIST measurements were performed for each paired baseline and post-treatment scan. Receiver operating characteristic analysis for the prediction of pCR was performed using logistic regression that included age and tumor size as covariates. SUV and SUL metrics were significantly different between orientation (P < .001), but were highly correlated (P > .98). Importantly, no differences were observed with the PERCIST measurements (P > .6). Overlapping 95% confidence intervals for the receiver operating characteristic analysis suggested no difference at predicting pCR. Therefore, prone and supine PERCIST in this data set were not statistically different.
Intraobserver Variability in Bladder Cancer Treatment Response Assessment With and Without Computerized Decision Support
Authors: Hadjiiski Lubomir M. , Cha Kenny H. , Cohan Richard H. , Chan Heang-Ping , Caoili Elaine M. , Davenport Matthew S. , Samala Ravi K. , Weizer Alon Z. , Alva Ajjai , Kirova-Nedyalkova Galina , Shampain Kimberly , Meyer Nathaniel , Barkmeier Daniel , A Woolen Sean , Shankar Prasad R. , Francis Isaac R. , Palmbos Phillip L.
Published: June 2020

We evaluated the intraobserver variability of physicians aided by a computerized decision-support system for treatment response assessment (CDSS-T) to identify patients who show complete response to neoadjuvant chemotherapy for bladder cancer, and the effects of the intraobserver variability on physicians' assessment accuracy. A CDSS-T tool was developed that uses a combination of deep learning neural network and radiomic features from computed tomography (CT) scans to detect bladder cancers that have fully responded to neoadjuvant treatment. Pre- and postchemotherapy CT scans of 157 bladder cancers from 123 patients were collected. In a multireader, multicase observer study, physician-observers estimated the likelihood of pathologic T0 disease by viewing paired pre/posttreatment CT scans placed side by side on an in-house-developed graphical user interface. Five abdominal radiologists, 4 diagnostic radiology residents, 2 oncologists, and 1 urologist participated as observers. They first provided an estimate without CDSS-T and then with CDSS-T. A subset of cases was evaluated twice to study the intraobserver variability and its effects on observer consistency. The mean areas under the curves for assessment of pathologic T0 disease were 0.85 for CDSS-T alone, 0.76 for physicians without CDSS-T and improved to 0.80 for physicians with CDSS-T (P = .001) in the original evaluation, and 0.78 for physicians without CDSS-T and improved to 0.81 for physicians with CDSS-T (P = .010) in the repeated evaluation. The intraobserver variability was significantly reduced with CDSS-T (P < .0001). The CDSS-T can significantly reduce physicians' variability and improve their accuracy for identifying complete response of muscle-invasive bladder cancer to neoadjuvant chemotherapy.
HUBUNGAN TINGKAT STRESS DENGAN SIKLUS MENSTRUASI PADA REMAJA PUTRI
Authors: Anjarsari Nurul , Sari Etika Purnama
Published: June 2020

Pendahuluan : Psikologis pada usia remaja dapat mempengaruhi emosi remaja yang dapat menyebabkan timbulnya stress. Stress pada remaja perempuan salah satunya dapat mengganggu siklus menstruasi. Tujuan penelitian untuk mengetahui hubungan tingkat stress dengan siklus menstruasi pada remaja.Metode : Penelitian ini menggunakan pendekatan cross sectional. Sampel dalam penelitian adalah 92 remaja putri kelas 2 SMA Wachid Hasyim 1 Surabaya yang diambil dengan teknik Simple Random Sampling. Instrumen pengumpulan data tingkat stres dengan menggunakan Kuesioner DASS 42 dan kuesioner siklus menstruasi, serta uji korelasi Chi-Square.Hasil : Hasil uji korelasi Chi-Square didapatkan nilai p=.016. Hal ini berarti terdapat hubungan antara tingkat stress dengan siklus menstruasi.Kesimpulan : Terdapat berbagai macam factor yang berkaitan dengan ketidakteraturan siklus menstruasi pada remaja dimana salah satunya adalah stress. Perlu dilakukan penelitian lagi terkait dampak stresss terhadap masalah menstruasi yang lain seperti durasi, dismenore dan lainnya untuk memahami lebih jauh dampak stress terhadap masalah menstruasi pada remaja. ABSTRACTIntroduction: Psychological changes in adolescence can affect adolescent emotions that can cause stress. Stress in adolescent one of which can disrupt the menstrual cycle. The purpose of this study was to determine the relationship of stress levels with the menstrual cycle in adolescents.Method: his study uses a cross sectional approach. The sample in this study was 92 adolescents of Wachid Hasyim 1 Surabaya High School who were taken by using Simple Random Sampling technique. Instrument for collecting stress levels using the DASS 42 Questionnaire and menstrual cycle questionnaire.Results: . This study tested using Chi-Square correlation test. Chi-Square correlation test results obtained p-value = .016. This means that there is a relationship between stress levels and the menstrual cycle.Conclusion: There are various factors related to irregular menstrual cycles in adolescents where one of them is stress. Further study needs to be conducted related to the impact of stress on other menstrual problems such as duration, dysmenorrhea and others to further understand the impact of stress on menstrual problems in adolescents.
Conséquences du stress sur la fonction immunitaire chez les animaux d’élevage
Authors: MERLOT E.
Published: June 2020

Cet article présente comment des situations de stress aigu (un transport, un regroupement) ou chronique (conditions de logement contraignantes) affectent la fonction immunitaire chez les animaux d’élevage. La réponse de stress est caractérisée par l’activation de l’axe corticotrope, dont les hormones inhibent l’activité des leucocytes, et la libération de nombreuses autres hormones et neuromédiateurs immunoactifs et immunosuppresseurs (hormone de croissance, prolactine, enképhalines…). Ainsi, l’augmentation transitoire du ratio neutrophiles / lymphocytes dans le sang et l’inhibition de la capacité des lymphocytes sanguins à proliférer sont des indicateurs d’une réponse de stress. D’autres tests sont plus informatifs car ils mesurent les effets du stress sur des fonctions immunitaires précises. Des fonctions relevant de l’immunité innée, première ligne de défense de l’organisme, sont sensibles au stress. Ainsi, la cytotoxicité des cellules tueuses naturelles sanguines est inhibée et des données chez les rongeurs montrent que la réponse inflammatoire peut être fortement déréglée. Certains facteurs de stress favorisent la production de cytokines inflammatoires et augmentent la sensibilité de l’organisme aux chocs septiques, tandis que d’autres inhibent la migration des polynucléaires vers un site d’infection, limitant ainsi la réponse inflammatoire et retardant le phénomène de cicatrisation. Les lymphocytes, vecteurs de l’immunité acquise, constituent la seconde ligne de défense. Le stress peut inhiber le développement de la réponse lymphocytaire à un antigène, par exemple une réponse vaccinale. Il inhibe les réponses de type cellulaire mais affecte peu, voire même parfois stimule, la production d’anticorps. L’altération des réponses innées et acquises diminue la résistance des animaux aux infections virales ou bactériennes.
Intérêts du pâturage hivernal sur parcours pour les exploitations ovines : exemple des Préalpes du sud
Authors: GAUTIER D. , MOULIN C.H.
Published: June 2020

Les objectifs de l’étude sont, d’une part, de proposer des recommandations techniques pour faire pâturer des brebis en hiver sur des parcours des Préalpes du sud, et d’autre part, de faire une analyse technico-économique de deux scénarios d’intégration du pâturage hivernal dans le fonctionnement d’une exploitation ovine. Lorsque l’accès foncier à des parcours de proximité bien exposés est possible, le pâturage hivernal peut être envisagé pour des brebis à l’entretien, avant la lutte de printemps, ou pour des brebis gravides. Les mêmes performances zootechniques que celles obtenues par une alimentation intégrale en bergerie peuvent être espérées. Le pâturage hivernal, qui substitue un stock d’herbe séchée sur pied à des fourrages conservés, permet une réduction des charges d’alimentation : les besoins en foin pour l’hiver sont diminués de 40 à 60 %. Les surfaces de parcours nécessaires sont importantes, 35 à 58 ares par brebis, avec une valorisation possible de 200 journées x brebis par hectare. Les simulations économiques prévoient ainsi une augmentation de l’excédent brut d’exploitation de 13 à 20 % : le pâturage hivernal sur parcours présente un réel intérêt économique pour les exploitations ovines. A l’échelle d’un territoire, il peut ainsi contribuer au redéploiement de l’élevage ovin sur les surfaces pastorales, permettant à celui-ci de remplir les fonctions environnementales attendues dans le cadre du second pilier de la politique agricole commune.
Sex-ratio chez les oiseaux sauvages et domestiques
Authors: BATELLIER F. , GOVOROUN M. , BRILLARD J.P.
Published: June 2020

Les chromosomes sexuels déterminent le sexe des embryons chez les oiseaux comme chez tous les vertébrés supérieurs. Le sex-ratio de la descendance d’une population est donc, d’après la théorie mendélienne, équilibré, méiose oblige. On rencontre pourtant des contre-exemples à la fois dans les espèces d’oiseaux sauvages et domestiques. La femelle oiseau pourrait ainsi soit contrôler la répartition des chromosomes sexuels dans ses ovocytes, soit favoriser le développement des embryons d’un sexe donné. L’objet de cette revue est de préciser les conditions d’apparition de ce contrôle. Enfin, si ce déséquilibre est confirmé, la connaissance des mécanismes qui le régulent pourrait permettre à terme un contrôle du sexe des populations d’oiseaux. En production avicole, un tel contrôle fait l’objet d’un vieux rêve : orienter les lignées de poules pondeuses vers la production de femelles alors que les lignées de poulets de chairs ou les canards mulards seraient orientées vers la production de mâles.
The Complexity of Mathematics
Authors: Vega Frank
Published: June 2020

In mathematics, the Riemann hypothesis is a conjecture that the Riemann zeta function has its zeros only at the negative even integers and complex numbers with real part 1/2. Many consider it to be the most important unsolved problem in pure mathematics. It is one of the seven Millennium Prize Problems selected by the Clay Mathematics Institute to carry a US 1,000,000 prize for the first correct solution. We prove the Riemann hypothesis using the Complexity Theory. Number theory is a branch of pure mathematics devoted primarily to the study of the integers and integer-valued functions. The Goldbach's conjecture is one of the most important and unsolved problems in number theory. Nowadays, it is one of the open problems of Hilbert and Landau. We show the Goldbach's conjecture is true using the Complexity Theory as well. An important complexity class is 1NSPACE(S(n)) for some S(n). These mathematical proofs are based on if some unary language belongs to 1NSPACE(S(log n)), then the binary version of that language belongs to 1NSPACE(S(n)) and vice versa.
Seasonal Variations and Immune Responses: Any Succor for COVID-19 Pandemic in Nigeria
Authors: Adeshakin Adeleye , Ayanshina Oluwamuyiwa , Afolabi Lukman , Adeshakin Funmilayo , Alli-Balogun Ganiyu , Essien-Baidoo Samuel , Wan Xiaochun
Published: June 2020

There is a global rise in the emergence of infectious diseases and the enigmatic coronavirus disease 2019 (COVID-19) being the most recent one. It is ravaging the world with little understanding of its etiology and factors affecting its transmission dynamics. Meanwhile, seasonal variations in weather are major factors impacting infectious disease transmission patterns. Developing countries are likely to be most affected by weather changes, largely because of challenges such as inadequate drainage and sewage management systems, healthcare facilities, education, and funding to efficiently mitigate infectious diseases. In Nigeria, weather conditions alternate between rainy and dry seasons. Conditions such as rainfall, flood, and humidity have been reported to influence infectious disease transmission. Thus, understanding the impact of weather changes in transmission dynamics and immune response to COVID 19 will help in preventive measures and policy making to curtail its spread most especially in Nigeria as the rainy season fully sets in.
Emergence of RBD and D614G Mutations in Spike Protein: An Insight from Indian SARS-CoV-2 Genome Analysis
Authors: SAMYUKTHA VINAYAGAM , NAVEEN KUMAR VENKATESAN
Published: June 2020

Currently, entire world is crumbled due to COVID-19 caused by novel SARS-CoV-2. Globally, over 5 million people are infected by SARS-CoV-2 with 6% fatality rate. The surface spike (S) protein plays a key role in the pathogenesis of SARS-CoV-2 by mediating viral entry through human angiotensin converting enzyme 2 (hACE2) receptors on the host cell and there is a big global race to find viral neutralizing antibodies and vaccine against S protein of SARS-CoV-2. Since SARS-CoV-2 evolved into 10 different clades in a very short span, a study on sipke protein mutation is essential to have effective vaccine coverage globally. Based on the mutation analysis of S protein from 166 Indian SARS-CoV-2 genome, a total of 40 different SNPs comprising of 14 synonymous and 26 non-synonymous mutations were observed, and notably, Indian S protein diverged into two major clusters, D614 and G614, with 11 different types. Majority of Indian strains fall in A2a and O clusters. Alarmingly, we have observed six SNPs at RBD and notably two of them at RBM (S438F and S494P). S494P SNP, similar to Bat–SARS like-CoV, may indicate a low ACE2 binding affinity. Interestingly 38% of Indian strains harbor a characteristic D614G SNP which was found predominantly in A2a cluster, mostly comprising USA and European strains with high disease severity. The association of disease severity with D614G SNP is well-correlated in states with high death rate except Maharashtra. Notably, more than 50% of D614G mutation were observed in Northern part of India and 14% in Southern part but not in Kerala and Tamil Nadu strains. Highly conserved motif, D614 (608-VAVLYQDVNCT-618) in upstream and also few downstream, of S1/S2 furin cleavage site may indicate specific key role in efficient interaction with host proteases in pathogenesis. Further studies are warranted to clarify the impact of SD614G SNP association to disease severity . Interestingly, C2367T (Y789Y) synonymous SNP is observed in 37% of Indian strains and notably similar SNPs with degeneracy bases were observed which is a key indication for the possibility of misdiagnosis by Real-Time PCR and revised strategies are needed for the precise diagnosis. Circulation of high number of signature SNPs [D614G and C2367T (Y789Y)] in certain states may be an early indication of emergence of community transmission in India. Further large genome sequence data from India will aid in deep understanding on the diversity of circulating SASR-Cov-2 and its impact on disease severity, origin of imported cases to India, community spread, effect on diagnosis and vaccine coverage.
The Influence Dose of Nicotine Exposure on H520 Smoking-related Non-Small-Cell Lung Carcinoma Cell Growth and Toxicity
Authors: Wu Jia-Ping , Peng Ching-Yi
Published: June 2020

Nicotine exposure may affect NSCLC is associated with lung cancer in humans. Whether nicotine exhibits carcinogenesis promoted activities in tumor growth still unknown. Nicotine is known to have dichotomous effects on cancer biology, acting like a pro- or anti-carcinogenesis agent. There are different functions between adenocarcinoma and squamous NSCLC cancer cells. Excess generation of nicotine may inhibit mitochondrial metabolism, protein modification, and DNA cleavage. Materials and Methods: We used the H520 NSCLC line obtained from human lung epithelial cells to detected nicotine growth and toxicity using MTT assay and western blotting. The concentration of nicotine stimulated cell growth to correspond to low concentration, while high concentration was cytotoxic. Results: According to MTT assay results, at 1.0 μM nicotine has significantly enhanced the H520 cell viability (%). Nicotine induced lung cancer carcinogenesis through mechanisms of α7nAchR, EGFR, HDAC2/4/5, Cyclin D/Cyclin E, Bcl-2, p-Akt, and inflammatory proteins of NF-KappaB and COX2 increases at 1.0 μM. Apoptosis proteins were decreases at 1.0 μM nicotine by p21, p27, c-jun, and p38α using western blotting. Nicotine stimulates tumor growth is mediated through α7nicotinic-acetylcholine receptors (α7nAChR), possibly involving inflammation. On the other hand, at high nicotine concentrations (> 1.0 μM) with consistent cytotoxic effects and appeared to be due to direct cell kill. Nicotine can prevent apoptosis induced by NSCLC. Conclusion: Therefore, the effects on chemotherapeutics by NSCLC malignant cell lines, nicotine in concentrations as low as 1.0 μM decreased. These mechanisms are responsible for the genotoxic effects caused by nicotine. This leads to downstream effects on decreased apoptosis, increased cell proliferation and transformation. The malignant NSCLC cells respond to the treatment with nicotine in lung cancer, the nicotine-mediated induction of growth may provide one of its links to α7nAchR or EGFR.
Robust Haebara Linking for Many Groups in the Case of Partial Invariance
Authors: Robitzsch Alexander
Published: June 2020

The comparison of group means in item response models constitutes an important issue in empirical research. The present article discusses an extension of Haebara linking by proposing a flexible class of robust linking functions for comparisons of many groups. These robust linking functions are particularly suited to item response data that are generated under partial invariance. In a simulation study, it is shown that the newly proposed robust Haebara linking approach outperforms existing approaches of Haebara linking. In an empirical application using PISA data, it is illustrated that country means can be sensitive to the choice of linking functions.
As alterações da LINDB e a ponderação dos atos administrativos
Authors: Marcondes Martins Ricardo
Published: June 2020

Examina-se neste estudo o impacto das alterações da Lei de introdução às normas do direito brasileiro (Decreto-lei 4.657/42), empreendidas pela Lei Federal 13.655/18, sobre a teoria dos atos administrativos. Fez-se um breve panorama das principais alterações que essa teoria sofrera nos últimos anos: primeiro, em decorrência da aplicação a ela da teoria dos três planos jurídicos, e, pois, da percepção de que atos inválidos, quando eficazes, geram efeitos no mundo jurídico; segundo, da consequente reformulação da teoria da extinção dos atos e do desenvolvimento da teoria da modificação; terceiro, em razão da teoria da ponderação e, por conseguinte, da revisão da edição e da correção normativas. Concluiu-se que as alterações legais resultaram do fato de que a comunidade jurídica não vem atentando para a evolução científica do tema no cotidiano da administração pública brasileira. Procurou-se, pela edição da lei, levar os órgãos de controle a atentarem para esses avanços.
Geração distribuída e desenvolvimento sustentável
Authors: Campigotto Soethe Ghabriel , Blanchet Luiz Alberto
Published: June 2020

Por meio de revisão bibliográfica, consulta na legislação e acesso a sítios eletrônicos mantidos pelo poder público, busca-se uma solução concreta que torne a energia elétrica importante pressuposto material do Desenvolvimento Sustentável. Em 2004, o instituto da Geração Distribuída foi introduzido no ordenamento jurídico brasileiro, mas apenas em 2012, o acesso aos sistemas foi viabilizado. O número de conexões tem crescido exponencialmente nos últimos anos, mas seu potencial ainda é latente. Diante de sua complexidade enquanto subsistema do Setor Elétrico Brasileiro, a Geração Distribuída tem apresentado peculiaridades favoráveis ao Desenvolvimento Sustentável, mas que só foram possíveis de constatação em função do uso da metodologia científica hipotético-dedutiva.
Methods for Prevention of Winter Slippery
Authors: Pshembaev M. K. , Kovalev Ya. N. , Yaglov V. N. , Girinsky V. V.
Published: June 2020

There are several methods for prevention of winter slippery on the roads – frictional, thermal, chemical, combined and structural. The friction method of combating slippery has found quite wide application. The method is based on increasing a wheel grip with iced road. Sand, slag, screening of stone materials and friction materials subjected to heating are used as a friction raw material. A thermal method is divided in conductive and convective according to a surface heating type in which a pavement is heated from below (electric heating) or from above (with a heat stream). Disadvantages of this method are its high cost when using thermal jets and harmful effects of high temperatures on a road surface. Nowadays a chemical method is considered as the most popular one to combat winter slippery. Treatment with solid or liquid reagents is provided in order to prevent slipping on the road surface or removing ice from it. The principle of their action is to lower a freezing temperature of the solution on the surface of the roadway. The fight against winter slippage is mainly carried out in a combined way by sprinkling roads with a sand and salt mixture. Currently, there is a need to completely or partially abandon the use of chlorides in the fight against winter slippery. In this case, the most promising direction is to prevent icing by creating coatings for roads with anti-icing properties that is introduction of anti-icing reagents in the composition of the road surface (construction method). This method makes it possible to increase cost of a finished road surface.
Autonomous Valve Controls Excess Water, Gas Production To Increase Oil Recovery
Authors: Mathiesen Vidar , Brough Brent
Published: June 2020

Increasing sensitivity to oil price fluctuation requires operators to reduce costs of operation. A key component is collaborative management by operators and suppliers to reduce cost over the full life cycle of the operation. Much of the focus is on the equipment-purchasing strategy; nonetheless, effective technology such as an autonomous inflow control valve could also benefit the operating expenditure (OPEX) savings by enhancing oil recovery and reducing processing costs of excessive unwanted water and gas in surface facilities.

OPEX comprises labor, chemicals, consumables, infrastructure maintenance, transportation, disposal, and other utilities. Capital expenditure (CAPEX) may also be reduced for long-term projects, which generally comprise infrastructure such as pipelines, pumps, disposal wells, ponds/storage treatment facilities, and other associated utilities infrastructure.

The average cost for handling produced water starts from about $1.50/bbl, depending on the geographical location of the operation. Such costs may justify an assessment of an autonomous inflow control valve (AICV) to reduce unwanted water and gas to achieve OPEX savings.

Horizontal wells are a proven option to maximize reservoir contact in certain situations. A challenge is often early water breakthrough in less than 6 months from starting production, and then progressively producing very-high water cuts, often 95%, for long periods of times thereafter. Inflow control device (ICD) technology has demonstrated potential in improving recovery in horizontal oil wells by delaying the gas and/or water breakthrough. However, ICDs cannot restrict water effluents once breakthrough occurs. A new generation of inflow control technology known as an AICV can balance the production flow and choke and shut the water-effluent zones once breakthrough occurs.

Basis of Design

The design is based on the Hagen-Poiseuille equation and Bernoulli’s principle. It uses the difference in fluid-flow behavior in the laminar- and the turbulent-flow restrictor to differentiate the pressure drop using the mobility ratio between oil, water, and gas. Light-viscosity fluids such as water and gas have high mobility and allow the AICV to detect the mobility difference, then choke and shut the main inflow area in the valve autonomously. Fig. 1 illustrates the construction of the valve in open positions, showing the direction of flow with arrows and the P1, P2, and P3 pressure locations. The inlet pressure is represented by P1: 2-5% of the main flow will move through the laminar-flow element (LFE) that will reduce the pressure to P2. Further pressure reduction occurs in the turbulent-flow element (TFE) to P3 as the tubing pressure. The differential pressure in LFE reacts to the piston’s effective area, resulting in a force balance around the piston to control the valve’s function (e.g., to open, choke, or close the main flow).
Technology Focus: Stimulation (June 2020)
Authors: Chang Frank
Published: June 2020

The economic condition of the oil and gas industry is tighter than ever. Optimizing well productivity to maintain cost effectiveness is on every operator’s mind. Enhancing well productivity requires more-detailed analysis, more measurements, and even-more-advanced products and technologies, which all cost more money. Doing more and reducing cost can be a dilemma. This is the time when properly choosing sound technologies is critical to improve efficiency and increase success rates. Several well-stimulation products and techniques have been seen to benefit well productivity from recent field trials and implementations in carbonate reservoirs, including simpler acid fluid systems, integrated work flows, and coiled-tubing bottomhole assemblies.

Emulsified acid has been a preferred carbonate-stimulation fluid for 30 years. Clearly, mass transfer can be retarded significantly by the emulsion form for deeper live-acid penetration in matrix- and fracture-acidizing applications. The quality of the emulsified acid is sensitive to how it is mixed. In the laboratory, slowly adding acid into oil, mostly diesel, containing surfactant while blending is required to achieve good emulsion stability. Field practice is another story. The large amount of emulsified acid is normally batch-mixed in the service company yard or at the wellsite by circulation pumps and tanks. The mixing energy used in the laboratory is difficult to match in the field. Consequently, the consistency of the final emulsified acid pumped can vary from well to well. Recently, single-phased-acid systems have been developed to simplify the fluid preparation and to make the product performance more robust. Various single-phased acids are provided by service companies or even operators themselves using different formulations to achieve the effect of retardation.

Another important technology for successful acidizing, especially in horizontal wells or highly heterogeneous reservoirs, is diversion. Many diverters have been used. Evaluation of diversion during the treatment remains rudimentary. Pressure humps are used to infer diversion without good confirmation of how effective the diversion actually is. More-accurate information about fluid rheological and friction characteristics is needed to evaluate the downhole-pressure behavior and, hence, quantified diversion results. The term “diversion” is often used interchangeably with “placement.” Proper placement can be achieved by means other than diverting materials. Jetting is believed to place acid effectively in matrix stimulation without chemical diverters.

Each technology costs additional money at the early stage. When they are routinely used, fully integrated in work flows, and eventually linked with automation, true cost effectiveness of the stimulation treatments can be realized. The investment made today, therefore, will bear fruits in the future.
Technology Focus: Hydraulic Fracturing (June 2020)
Authors: Rahim Zillur
Published: June 2020

A good design of a multistage-fracture (MSF) treatment must be implemented effectively to ensure expected production from a fracture treatment. Knowing that downhole tools are correctly deployed and function as planned in MSF, therefore, is important. The setting of packers, opening and closing of frac ports, shifting of frac sleeves, and isolating with ball drops in openhole assemblies are some of the many major events that need to be monitored closely to ensure smooth operations. As such, wellbore pressure is monitored at surface and is the primary method for deter-mining if tools are functioning properly and if the stimulation program is being executed correctly. As wellbores become longer, numerous fracturing stages are conducted on a single wellbore, and multiple service companies are involved on site to support a successful stimulation program, pinpointing issues or challenges when they arise becomes more difficult - particularly if the pressure signature is unclear, hard to interpret, or not present at all. These ambiguities can lead to treatment uncertainty, costly delays, or huge remedial efforts. Being uncertain and missing out on a few stages in the treatment can have major effects on production, ultimate recovery, and the overall field-development plan.

A new real-time-visualization (RTV) technology combined with high-resolution pressure reading and acoustic sensors is being used to overcome operational difficulties and to optimize stimulation efforts by reducing uncertainty. The RTV technology has a minimal surface footprint, can be deployed rapidly, is self-contained, and does not interfere with concurrent on-site operations. The use of this technology significantly improves the entire fracturing process, thereby optimizing well production.

RTV has been used in more than 10 countries, proving to be an effective tool for confirming successful operations or expediting the troubleshooting of operational issues. In one case, an operator was facing challenges in establishing connectivity with the reservoir when a toe sleeve failed to open. The RTV and acoustic system provided the operator valuable insight; the problematic sleeve was identified and opened with a coiled-tubing-deployed ball-seat activator immediately, preventing a remedial operation of milling out the entire completion system, which would have been very costly.

RTV has also been used offshore. Monitoring an openhole multistage stimulation system that was using ball-activated sliding sleeves, the RTV system confirmed all critical events, such as ball launches, landings, and sleeve shifts. The system prevented unnecessary use of extra balls or coiled tubing in cases where the pressure signature of sleeve shifts was not present.

Although many technologies and approaches are available to help with real-time monitoring and troubleshooting, incorporating this RTV system provides critical data to correct issues effectively and improves operational efficiency, giving operators greater confidence in decisions relating to downhole events.
Overcoming Challenges in Chemical EOR During Polymer Breakthrough
Authors: Carpenter Chris
Published: June 2020

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 194689, “Challenges in Selection and Use of Production Chemicals With Chemical EOR Operations During Polymer Breakthrough Phase,” by Robert Zagitov, Panneer Selvam Venkat, and Ravindranthan Kothandan, Cairn Oil and Gas, et al., prepared for the 2019 SPE Oil and Gas India Conference and Exhibition, Mumbai, 9-11 April. The paper has not been peer reviewed.

In chemical enhanced oil recovery (EOR), challenges are expected regarding production chemistry and production-facilities operations. Partially hydrolyzed polyacrylamide (HPAM) is used widely for controlling mobility ratios. Complex in water chemistry and rich in positively charged divalent ions, flooded polymer, having a negative charge, interacts with divalent ions of produced water (PW). The complete paper discusses the importance of adequate preparation and the approaches used to overcome challenges of EOR operations, including handling back-produced polymer.

Introduction

The Mangala field in northwest India, discovered in January 2004, is part of the Barmer Basin. The primary reservoir unit in this field is the Fatehgarh group, a high-quality quartzose sandstone reservoir having high net-to-gross ratio, high porosity (21-28%), and multidarcy permeability (200 millidarcy to 20 darcy) with an average permeability of approximately 5 darcy. The reservoir contains waxy crude with gravity ranging from 20 to 28 °API. A primary recovery efficiency of less than 10% stock-tank oil initially in place is estimated on the basis of simple depletion; thus, the base field-development plan envisaged implementation of waterflooding from the start of production to maintain reservoir pressure and sweep reserves. Detailed laboratory studies have established that aqueous-based chemical EOR processes are best suited for these viscous oil fields.

Full-field polymer flooding has been implemented in the Mangala field, with an injection at the time of writing of nearly 400,000 B/D of polymerized injection water (IW) with average polymer concentration of approximately 2,500 ppm. HPAM is mixed with source water to create a mother solution of 15,000-ppm concentration at a central polymer facility and is distributed through a pipeline network to 15 well pads, where it is diluted with IW to achieve a viscosity of approximately 30 cp for injection. Artificial lift is achieved either by jet pump or electrical submersible pump. Average water cut is 80% at the time of writing.
Predictive factors of selective mineralocorticoid receptor antagonist treatment in chronic central serous chorioretinopathy
Authors: Gergely Róbert , Kovács Illés , Récsán Zsuzsanna , Sándor Gábor László , Czakó Cecília , Nagy Zoltán Zsolt , Ecsedy Mónika
Published: June 2020

Purpose: To compare the macular morphology of good and poor responders to eplerenone treatment in chronic central serous chorioretinopathy (CSCR) patients. Methods: 30 eyes of 29 patients with chronic CSCR were treated with 50 mg/day oral eplerenone and followed up for one year. The integrity of outer retinal layers at baseline was assessed using optical coherence tomography. Patients who showed complete resolution of subretinal fluid at one year were assigned to the good responder group (Group 1), whilst those who showed moderate or no resolution were classified as poor responders (Group 2). Results: Ellipsoid zone interruption, ELM interruption and hyperreflective foci in outer segment (OS) and outer nuclear layer (ONL) was significantly more frequent in Group 2 than in Group 1 (p<0.05 for all parameteres). Outer segment elongation was significantly more frequently seen in Group 1 than in Group 2 (p<0.05) Multivariable regression analysis showed that intact ellipsoid zone at baseline is an independent predictor of good therapeutic response, with an odds ratio of 26.00 (95% CI: 3.69–183.45; p=0.001) after controlling for the effect of hyperreflective foci and ELM integrity.Conclusion: There is higher chance of the resolution of subretinal fluid after eplerenone treatment in CSCR patients with intact outer retinal layers at baseline. Baseline morphologic evaluation of the outer retinal layers on OCT scans can be useful in predicting the response to mineralocorticoid receptor antagonist therapy in these patients.
Pertussis outbreak in Southern Ethiopia: challenges of detection, management and response
Authors: Mitiku Aychiluhim Damtew , Argaw Mesele Damte , Desta Binyam Fekadu , Tsegaye Zergu Taffesse , Atsa Afework Ayele , Tefera Bekele Belayihun , Teferi Ephreme , Rogers Deirdre , Ali Ismael , Gebeyehu Asrat , Anjulo Desta , Abate Derebe Tadesse , Sendeku Agegnehu Gebru , Mulowa Rudzani
Published: June 2020

Background: Despite the availability of effective vaccines, pertussis remains endemic with high fatality rates in low and middle-income countries (LMIC).This study aims to describe an outbreak of pertussis in a health district of Ethiopia. The study highlights the challenges faced by the health system in identifying pertussis cases and appropriately responding to the outbreak at the district level. Methods: a descriptive cross-sectional study was conducted using data sourced from the District Public Health Emergency and Management (PHEM) surveillance service and outbreak management field reports. Stratified attack rates and fatality rates for pertussis are described. Systemic problems leading to the outbreak are explored and narrated. A modified CDC pertussis case definition was employed with a polymerase chain reaction used to confirm cases. Results: From September 2018 to January 2019, 1840 suspected, probable, and confirmed pertussis cases and six deaths were identified. Pertussis cases ranged from 1 month to 51 years in age and an outbreak occurred in 14 out of the 24 villages of Dara Malo district. The overall attack rate was 1708 per 100,000 population with a fatality rate of 3.3 per 1,000 pertussis cases. The highest attack rate of 12,689/100,000 was seen in infants. Among confirmed, probable and suspected pertussis cases, only 41.1% had completed the three-dose pertussis vaccine's primary schedule. The household survey revealed the population coverage of 73.4% and 40.8% for Pentavalent vaccine dose one and three respectively. Investigations suggested the existence of a poor cold chain management system in the study area. Conclusions: There is an urgent need to build capacity to strengthen routine vaccination services and improving the maintenance of the vaccine cold chain. Other Low-and Middle -Income Countries (LMICs), are urged to take lessons learned from this outbreak and strengthen their own vaccination programs and capacitate health workers to manage local outbreaks.
IgG anti-hinge antibodies against IgG4 F(ab’)2 fragments generated using pepsin are useful diagnostic markers for rheumatoid arthritis: implications of the possible roles of metalloproteinases and IgG subclasses in generating of immunogenic hinge epitopes.
Authors: Ota Toshiyuki , Ota Shun-ichiro , Uchino Ayumi , Nagano Shuji
Published: June 2020

Background. Pepsin agglutinators, discovered over 50 years ago, have been recently referred to as anti-hinge antibodies (AHAs) because of their reaction with the IgG hinge epitope. AHAs have different reactivity for each hinge epitope generated by each protease that cleaves the hinge region at different sites. Moreover, AHAs have different reactivity against different hinge epitopes derived from each IgG subclass even when the same protease is used. Since the expression of matrix metalloproteinase-3 (MMP-3) is enhanced in rheumatoid arthritis (RA), AHA production could also be increased. The purpose of this study was to determine whether the levels of AHAs against IgG hinge epitopes produced by MMP-3 are elevated in RA.Methods. The serum levels of IgG or IgA AHAs against the IgG1/IgG4 F(ab’)2 fragments, generated by either MMP-3 or pepsin, was measured using ELISA in 111 patients with RA and 81 healthy controls (HC). Receiver operating characteristic (ROC) analysis was used for obtaining optimal cutoff values and cutoff values indicating high specificity (>95%) of the AHA. The targeted epitope of a specific AHA was investigated through inhibition ELISA. Results. Seven AHAs were statistically higher in RA patients than HC, except IgG AHA against IgG1 F(ab’)2, which was generated by MMP-3 proteolytic cleavage. The areas under the ROC curve were of 0.66--0.80, although the sensitivities at high specificity were low (5.4--24.3%). The cumulative number of positive AHAs in each individual was statistically higher in RA patients than HC, suggesting the extreme extent of AHA repertoires in RA. Inhibition studies revealed that IgG AHAs against IgG4 F(ab’)2 fragments generated by pepsin cross-reacted with IgG1 F(ab’)2 fragments generated by pepsin. Multivariate logistic regression analysis identified the IgG AHA against IgG4 F(ab’)2 fragments generated by pepsin as an independent variable for RA diagnosis, even in RA patients who were negative for both RF and ACPA (odds ratio 1.18, 95% CI: 1.06−1.32; P=0.003). Additional experiments using non-RA patients finally strengthened the diagnostic utility.Conclusion. In RA patients, we observed diversification and amplification of AHA repertoires and diagnostic utility of the specific AHA against IgG4 F(ab’)2 fragments generated by pepsin but not MMP-3.
Early exposure to environmental sounds and the development of cortical auditory evoked potentials of preterm infants during the first three months of life
Authors: Cavalcanti Hannalice Gottschalck , Nunes Aryelly Dayane da Silva , Cunha Brenda Karla Silva da , Alvarenga Kátia de Freitas , Balen Sheila Andreoli , Pereira Antonio
Published: June 2020

Objective: Preterm infants are exposed earlier than their term counterparts to unattenuated sounds from the external environment during the sensitive period of the organization of the auditory cortical circuitry. In the current study, we investigate the effect of preterm birth on the course of development of auditory cortical areas by evaluating how gestational age (GA) correlates with the latency of the P1 component of the cortical auditory evoked potential (CAEP) of two experimental groups measured at one or three months of age. Results: Our sample consisted of 23 infants delivered at GA ranging from 31.28-41.42 weeks and separated into two groups evaluated transversally at one or three months of corrected age (CA). In the group evaluated at one-month CA, the latency of the component P1 was similar in both terms and infants classified as late-preterm (GA>32 weeks). However, in the group evaluated at three months CA, P1 latency was significantly smaller in preterms. These preliminary results suggest an acceleration of the development of auditory cortical pathways in preterms, probably due to their early exposure to socially relevant auditory stimuli from the external environment.