bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribuições metodológicas para os estudos sobre indicações geográficas: valorizar os recursos territoriais segundo as chaves de ação do Guia da EPAGRI, 2020, e do Guía Uniendo Personas, Territorios y Productos para Fomentar la Calidad Vinculada al Origen y las Indicaciones Geográficas Sostenibles, da FAO, 2011
Authors: Sampaio Giovanna Martins , Caldas Alcides dos Santos , Pinto Betina Americano Costa , Santos João Antonio Belmino dos
Published: August 2024

O presente trabalho objetiva traçar os principais pontos constantes na cartilha Metodológica da EPAGRI, Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina, como referencial no campo das indicações geográficas, num olhar em relação à proposta do Círculo Virtuoso da FAO, Agência de Alimentação e Agricultura da ONU. São estudos que podem contribuir para os processos de elaboração dos relatórios de solicitação de registro de indicações geográficas junto ao Instituto Nacional da Propriedade Industrial (INPI). Assim, o estudo consistiu numa revisão de bibliografia sistemática, de caráter descritivo e abordagem qualiquanti, com cunho empírico e com o uso de estudos e documentos secundários interdisciplinares e epistemológicos em torno do tema, bem como artigos e dissertações, livros e materiais digitais. Os resultados parciais encontrados nesses estudos metodológicos apontam que a valorização e o desenvolvimento territorial local são frutos de conhecimentos locais, tácitos e implícitos, que foram construídos e adquiridos com o passar dos anos em determinada região e comunidade, consistindo em verdadeiros bens e ativos intangíveis e passíveis de exploração via ecoturismo, por exemplo, primordialmente considerando o método da FAO do círculo virtuoso que permite articular os diferentes fatores territoriais, locais, culturais, sociais, econômicos, políticos e jurídicos em prol do desenvolvimento de certa localidade.
Agricultura familiar em Nova Friburgo: caracterização da gestão social e promoção da transição agroecológica
Authors: Antonio Gerson José Yunes , Assis Renato Linhares de
Published: August 2024

A importância da agricultura familiar em Nova Friburgo decorre da relevância da produção de hortaliças e flores, da manutenção de fragmentos florestais, da organização social e política para manutenção das conquistas e atendimento de anseios, como as estratégias agroecológicas a partir de evento climático extremo ocorrido em 2011. O objetivo foi caracterizar o município de Nova Friburgo nos aspectos territorial, ambiental, histórico, produtivo e organizacional, assim como destacar a presença de dinâmicas camponesas e empresariais nos sistemas de produção locais. Foram realizadas 47 entrevistas com agricultores e 4 com atores-chave in loco, utilizando de questionário semiestruturado com 57 perguntas, associado à aplicação de ferramenta participativa inovadora em que se diagnosticaram aspectos sociais, produtivos, ambientais e da dinâmica local da transição agroecológica. Ressalta-se a importância de fortalecer a ação de agentes de desenvolvimento rural sustentável, representados pela pesquisa participativa, extensão rural coletiva e assistência técnica continuada em agroecologia, aproximando grupos de agricultura orgânica e agricultura convencional. Conclui-se, a partir da caracterização do município, que a busca da sustentabilidade da agricultura familiar do município deve se apoiar em um processo de gestão social, integrado à ação de agentes externos, representados pela pesquisa participativa, extensão rural coletiva e assistência técnica em agroecologia e de valorização da riqueza histórica e diversidade de cultivos dessa produção, proveniente de agricultores familiares, organizados socialmente de forma associativa, visando ao desenvolvimento rural sustentável.
Oficinas estéticas no Morro da Queimada: memórias em processo
Authors: Nardi Rafaela Carolina , Zanella Andréa Vieira , Strappazzon André Luiz , Severino Larissa Franco
Published: August 2024

Investigar as memórias de oficinas de arte oferecidas em um território periférico de Florianópolis, Santa Catarina, é o objetivo desta pesquisa. A aproximação da equipe de pesquisa com o território iniciou em 2017, através de oficinas estéticas oferecidas na Cooperativa no Morro da Queimada. A maioria dessas oficinas não teve continuidade, porém permanecem no local rastros do que ali acontecia. A partir das perspectivas Benjaminiana e Vigotskiana, considera-se a importância do trabalho com os restos, com aquilo que é jogado fora, rejeitado, esquecido. Importam esses restos à investigação em psicologia pois, embora considerados minúcias insignificantes, são vestígios de outros possíveis não concretizados que, uma vez perscrutados e visibilizados, podem vir a contribuir para a compreensão e transformação do presente. Foram realizadas 10 entrevistas com mulheres participantes das oficinas. A metodologia de análise dos dados foi a análise do discurso, a qual nos permitiu compreender o que motivou e o processo de construção das oficinas, a participação comunitária, as eventuais repercussões, os motivos para descontinuidades e o que ficou como memória para as participantes. Como resultados, constatou-se que, apesar do fim das oficinas, algumas aprendizagens persistiram e foram transmitidas de geração em geração, principalmente aquelas em que havia um sentido mais amplo como, por exemplo, a tradição do fazer chocolate para entregar na páscoa às crianças da comunidade. Outro resultado obtido foi a compreensão da importância dada às oficinas como locais de concretização de encontros e de compartilhar experiências de vida.
Desenvolvimento local e possibilidades de uma economia circular a partir de uma cooperativa de catadores de materiais recicláveis
Authors: Silva Christian Luiz da , Sauka Jean Elizeu
Published: August 2024

O desenvolvimento da sociedade moderna nos grandes centros urbanos encontra-se atrelado a um sistema de consumo que vem carregado de problemas territoriais, políticos e socioambientais. Sendo o Brasil considerado o quarto maior gerador de resíduos sólidos do mundo, fica evidente a importância de ações estratégicas vindas de esferas públicas, privadas e sociedade civil que visem a melhores condições na gestão e à valorização desses resíduos. Diante disso, famílias e cooperativas atuam na catação e triagem de materiais recicláveis e podem ser conceituados como agentes de práticas sustentáveis. O presente artigo tem como objetivo investigar a interface entre a organização territorial e o desenvolvimento local juntamente com uma cooperativa de reciclagem. Para compreender as dinâmicas socioambientais desta pesquisa, construiu-se um portfólio bibliométrico que propiciou conhecimentos acerca de práticas da Economia Circular e catadores de materiais recicláveis. Para a coleta de dados, buscou a sustentação por meio da observação não participante e entrevistas estruturadas e semiestruturadas. Os resultados mostraram que o fortalecimento da cooperativa se desenvolve a partir de relações sociais instituídas nos entornos da cadeia de reciclagem. Conclui-se que, da viabilidade de relações dentro do território, podem surgir cenários que garantam a circularidade e transformação do resíduo, englobando aspectos voltados para sustentabilidade social, ambiental e econômica.
Transcriptomic analysis of plasma-derived small extracellular vesicles reveals the pathological characteristics of normal tension glaucoma
Authors: Xu Sheng-Lan , Li Jun-Hua , Zhang Wen-Meng , Fu Meng-Jun , Xing Hui-Min , Ma Hua , Gong Xian-Hui , Wu Rong-Han , Liang Yuan-Bo , Cui Ren-Zhe , Chi Zai-Long
Published: August 2024

Aim: Normal tension glaucoma (NTG) is a common optic neuropathy that can be challenging to diagnose due to the intraocular pressure remaining within the normal range. Early diagnosis and intervention are crucial for the effective lifelong management of patients.

Methods: This study recruited a total of 225 participants. Small extracellular vesicles (sEVs) RNA from circulating plasma was analyzed via transcriptomic sequencing, and its expression levels were verified by quantitative real-time polymerase chain reaction (qRT-PCR). Logistic regression, linear regression, and receiver operating characteristic (ROC) curve analyses were performed to examine the association of biomarkers with clinicopathological characteristics.

Results: Analysis of sEVs mRNAs in NTG patients revealed mitochondrial dysfunction and enrichment of central nervous system degenerative pathways, reflecting the pathological features of NTG. Compared with those in the controls, the expression levels of sEVs let-7b-5p in the plasma of NTG patients were significantly lower, with an area under the curve (AUC) of 0.870 (95%CI: 0.797-0.943) (P < 0.0001), and the AUC combined with age was 0.923 (95%CI: 0.851-0.996) (P < 0.0001). In addition, we found that let-7b-5p levels were significantly correlated with the severity and visual field defects of NTG patients and had good specificity compared with other ophthalmic diseases.

Conclusion: The sEVs RNA signatures in circulating plasma from NTG revealed mitochondrial dysfunction and that sEVs let-7b-5p can be a useful noninvasive biomarker for NTG.
Elementary Particles and Their Interaction with Space-Time Curvature
Authors: Lavi Eran Magshim
Published: August 2024

This article investigates the fundamental principles that establish universal limits in physical phenomena, such as the uniformity of physical laws and Energy conservation, leading to the concepts of maximum speed, locality, and maximum density. These principles guide me to explore Quantum Black Holes—relativistically rotating, miniature charged black holes with a singular core at the highest possible density. Uniquely, these Quantum Black Holes maintain all quantized charges, including gravitational ones. The study further demonstrates that quarks and leptons are composed of these Quantum Black Holes, redefining them as the actual elementary particles.Exploring these particles reveals that they emit Energy outward, modifying the curvature of nearby space-time. This discovery provides new insights into local space-time dynamics, characterized by a single equation that includes the influence of all charges and hidden Energy. By the conclusion of this article, I show that Quantum Black Holes offer explanations for several Standard Model deficiencies: the nature of luminous, dark, and anti-Matter; the mass, size, and quantized charges of all elementary particles (including gravitational); the nature of neutrino oscillations; and the mechanism by which electric charges remain bound even though the same type of electric charge components must repeal each other.
Deep Learning in Finance: Time Series Prediction
Authors: Muhammed Abdulkabir , Olaosun Korede Samuel , Popoola Seyi James , Byers Joe Wayne
Published: August 2024

The purpose of this project is to explore the potential of Long Short-Term Memory (LSTM), a type of recurrent neural network (RNN), as a tool for making directional predictions for assets. The focus will be on using LSTM for classifying up/down moves in stock indices, stocks, and FX rates (EUR/USD). Various financial ratios, advanced technical indicators, and volatility estimators will be used as features to enhance the predictive power of the model. Incorporating credit spreads and news indicators can also improve the model. The advantage of LSTM is its ability to handle sequences of arbitrary length, which means that longer time frames such as 5-day, 10-day, or 1-week returns can be used for prediction. Before using RNNs, exploratory data analysis (EDA) will be performed to understand the underlying patterns in the data. This may include dimensionality reduction techniques such as autoencoding, self-organizing maps, or decision tree regression. The results of the EDA will be used to guide the selection of features for the LSTM model. It is important to note that long memory and stationarity are common characteristics of time series data, such as interest rates or economic indicators. Power-law autocorrection, Hurst exponent fractional, or Markov processes may be used to model these data. Predicting 5-day, 10-day returns for equities or 1-week, 1-month returns for financial factors presents two challenges. First, a large amount of data is required, typically 7–10 years of data. Second, positive autocorrelation in the 5-day or 10-day returns in equity time series must be isolated.
The Use of Academic Library and Information Seeking Behavior of Students at Lusaka Apex Medical University
Authors: Mvula Dalitso
Published: August 2024

The study surveyed the use of academic libraries and information seeking behaviour of students at Lusaka Apex Medical University. The objectives of the study were to determine how often LAMU students used the libraries, to ascertain the purpose for which students used the library and to determine the challenges faced in accessing library services. Using a survey research design, 230 students selected using simple random sampling participated. Findings revealed that there were more male (51.1%) students who participated. The study also found that the majority of students (54.7%) were occasionally using the library. Results on the purpose for using the library showed that the majority (39.6%) were using it to read in order to improve personal competence. In relation to the challenges, majority students (42.6%) stressed the inadequacy of relevant materials. The need for librarians to make themselves available to aid students that seek information for different purposes was recommended. This was seen as a way through which many would have access to the available information in their field. There is a need for proper orientation and sensitization to students on how to access both physical and online materials. This would increase the library use as well as improve the performance of students. Lastly, it was recommended that a study on the digital literacy of students be done in order to ascertain their competence and search skills in sourcing for information.
Pneumatic Plantar Stimulation Device Replicating Manual Therapy Improves Lateral Stability in Standing Posture
Authors: An Qi , Hamada Hiroyuki , Maruta Shigeki , Abe Yuki , Takada Kenichi , Kikuchi Ken , Yamakawa Hiroshi , Asama Hajime , Yamashita Atsushi
Published: August 2024

Strokes are a widespread condition characterized by motor paralysis and sensory impairment, and they significantly hinder daily activities. Hence, rehabilitation aimed at improving motor function is crucial for post-stroke patients. Manual therapy, which involves the manual stimulation of the limbs to provide sensory input and enhance motor function, is commonly employed for rehabilitation. However, the limited duration of inpatient rehabilitation highlights the need for devices that can provide similar rehabilitation interventions at home. Here we elucidate the skills employed by physical therapists during intervention through interviews and measurements of the force applied to the plantar surface of the foot. Subsequently, we develop a device capable of replicating these intervention skills. The investigation of physical-therapist skills revealed the importance of stimulating the muscles involved in forming the longitudinal and transverse arches and the flexor muscles of the toes during manual therapy. The required force for stimulation was also noted. Using our device, which utilized pneumatic actuation to replicate therapist skills, intervention on the plantar surface of the feet of healthy adults demonstrated improved stability in their standing posture, particularly in the lateral direction. These devices can enhance the sensory-motor connection from the plantar surface, thereby improving motor abilities, such as preventing falls.
Augmented Bodily Self in Performing a Button-Touching Task with Soft Supernumerary Robotic Arms
Authors: Niiyama Ryuma , Yoshida Honoka , Kawamata Ryogo , Higo Katsuki , Shimada Sotaro
Published: August 2024

Extra or supernumerary robotic limbs are actively exploited in the field of body augmentation. The science of self-recognition of additional body parts is an interesting subject. Although the field is primarily led by psychological studies in virtual reality, which facilitate flexible experimental designs, we believe that assessments employing real robots are also essential. In this study, we investigated the sense of body ownership and agency of a dual-arm wearable robotic arm using an inexpensive and safe inflatable structure. We report the results of functional near-infrared spectroscopy (fNIRS) analysis of brain activity during the use of the robotic arm. The questionnaire results from the experiment, which involved a button-touching task, revealed that both the sense of ownership and sense of agency were significantly higher in the goal-oriented collaborative experience compared to the non-goal-oriented condition. This indicates that humans feel ownership of and agency toward an autonomous robot or a remote-controlled robotic arm operated by another person. The analysis of the fNIRS data included a two-factor analysis of variance for the learning and trial phases. While there was no main effect for the conditions within each phase, a significant interaction was observed between the two brain regions of the right angular gyrus and right postcentral gyrus.
Overturn Recovery of Working Six-Legged Robots on a Flat Slope with Preparatory Body Rotation
Authors: Honda Yuto , Kawaguchi Toshifumi , Inoue Kenji
Published: August 2024

A method for working six-legged robots to recover from an overturned state on a flat slope is proposed. The robot rotates around its roll axis, which is parallel to the slope, from an overturned state to a normal state. During this process, the robot supports its body using six legs and maintains as much static balance as possible. This enables a stable overturn recovery. Before recovery, the robot may rotate in the overturned state around its yaw axis, which is vertical to the slope, until the recovery direction becomes lateral to the slope. This reduces the risk of tumbling down the slope. Consequently, the robot can recover from the overturned state on the flat slope of 40° when it recovers almost in the lateral direction.
Adaptation of Motor Control Through Transferring Mirror-Image Kinematics Between Dual Arms
Authors: Nakamura Sota , Kobayashi Yuichi
Published: August 2024

Developing a learning model that adapts to changes in the body is critical for improving the flexibility of machine intelligence. During recovery from a controller malfunction, humans use the information obtained from previous experiences. One possible explanation for the recovery process is that information from the remaining controller was transformed and used. Modeling this mechanism will aid in the development of an adaptive motor-learning model capable of quickly recovering from controller malfunctions. We proposed a learning model for explaining the reused information of the remaining controllers in a pair of controllers. Simulations of a pair of upper limbs validated that the learning model could find a simple transformation, such as a reflection between the left and right arms, using optimization.
Homenajes filosóficos: entre la apatía y el reconocimiento (el caso Pallares Ronquillo-Rico Bovio, comentario historiográfico)
Authors: Ordóñez Burgos Jorge
Published: August 2024

En este trabajo se revisa el contenido de dos libros de homenaje acerca de dos profesores chihuahuenses de Filosofía: Enrique Pallares Ronquillo y Arturo Rico Bovio. Ambos reconocidos por su labor pedagógica y sus ideas. Sin embargo, existen varios cuestionamientos historiográficos que quedan sin resolver a lo largo de la mayor parte de los capítulos. ¿Cómo ha de describirse y comprenderse el trabajo filosófico de ambos?, ¿cuál es el medio político, social, intelectual y cultural en el que surgieron y se desarrollaron sus filosofías?, ¿qué vínculo tiene cada autor, que participó en los libros de homenaje, con Rico y Pallares?, ¿de qué manera contribuyen ambos textos con la flaca memoria de la filosofía local?
Intra-Articular Corrective Osteotomy for Distal Radial Intra-Articular Malunion Using Patient-Matched Instruments
Authors: Oka Kunihiro , Miyamura Satoshi , Shiode Ryoya , Tanaka Hiroyuki , Iwasaki Norimasa , Kawamura Daisuke , Sato Kazuki , Iwamoto Takuji , Yamamoto Michiro , Nishida Keiichiro , Shimamura Yasunori , Yamada Tomomi , Okada Seiji , Murase Tsuyoshi
Published: August 2024

Background:

Corrective osteotomy for intra-articular malunion is a challenging procedure. However, recent advancements, including patient-matched instruments created on the basis of preoperative computer simulation, enable accurate intra-articular correction. We hypothesized that intra-articular corrective osteotomy using patient-matched instruments for the treatment of distal radial intra-articular malunion would reduce intra-articular deformity and restore wrist function at 12 months of follow-up.

Methods:

This prospective study included 12 patients with distal radial intra-articular malunion who underwent intra-articular corrective osteotomy external to the joint using patient-matched instruments. The primary end point was the maximum step-off on the articular surface of the distal radius, measured with use of computed tomography (CT), with an expected postoperative value of ≤1.5 mm. The secondary end points included the gap of the articular surface; range of motion; grip strength; pain evaluated using a visual analog scale (VAS); patient satisfaction; Disabilities of the Arm, Shoulder and Hand (DASH) score; and Patient-Rated Wrist Evaluation (PRWE) score. A mean postoperative step-off of ≤1.5 mm for the primary end point was assessed with use of the 1-sample t test. The secondary end points were assessed with use of the Dunnett multiple comparison test.

Results:

The average step-off significantly improved from 3.75 ± 1.04 mm preoperatively to 0.51 ± 0.40 mm at the 52-week postoperative follow-up and was maintained within 1.5 mm. The average wrist and forearm range of motion, VAS score, grip strength, DASH score, and PRWE score significantly improved. Eleven patients were either very satisfied or satisfied with their outcomes.

Conclusions:

The use of patient-matched instruments could contribute to improving postoperative outcomes of intra-articular corrective osteotomy procedures involving the distal radius.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Analysis of Prey, Predator and Top Predator Model Involving Various Functional Responses
Authors: B. Divya , K. Kavitha
Published: August 2024

يقترح هذا البحث نموذجا رياضيا لدراسة السلوك الديناميكي لنظام ثلاثة أنواع، وهي الفريسة والمفترس والمفترس العلوي. يعد سلوك التغذية لكل حيوان مفترس بمثابة استجابة وظيفية. يتم التفاعل بين الأنواع عن طريق الاستجابة الوظيفية. يتم دمج الاستجابة الوظيفية لكراولي مارتن بين الفريسة والمفترس بينما تحدث الاستجابة الوظيفية من النوع الثالث هولينج بين المفترس والمفترس الأعلى. تم فحص وجود إيجابية وحدود النظام. يتم تحديد نقاط التوازن للنظام. لقد تم جعل النظام خطيا من خلال تطبيق المصفوفة اليعقوبية. المنظور الرئيسي المستخدم لمناقشة ديناميكيات النظام هو الديمومة والاستقرار. يتم إجراء مزيد من تحليل استقرار النظام عند كل نقطة توازن. لفهم ديناميكيات النظام النموذجي، تم دراسة الاستقرار المقارب للعديد من حلول التوازن، المحلية والعالمية. تُستخدم معايير روث هورويتز لتحليل الاستقرار المحلي عند كل نقطة توازن. باستخدام وظيفة Lyapunov المناسبة، تم إنشاء الاستقرار المقارب العالمي لحل التوازن الداخلي الإيجابي. من منظور بيولوجي، يعتبر النظام دائمًا إذا استمرت جميع سكانه في الوجود في المستقبل. تم تحديد وجود شروط دوام النظام. لدعم النتائج التحليلية، تم إجراء العديد من عمليات المحاكاة العددية باستخدام برنامج MATLAB. وأخيراً وبالاعتماد على نتائج المحاكاة التحليلية والعددية تمت مناقشة تأثير الاستجابة الوظيفية بين الفريسة والمفترس والمفترس العلوي..
New Approximating Results by Weak Convergence of Forked Sequences
Authors: Salman Bareq Baqi , Abed Salwa Salman
Published: August 2024

تعتبر الفضاءات المعيارية هي تعميم طبيعي لبعض الفضاءات مثل فضاء  Lebesgueو فضاءOrlicz  و فضاء Lorentz P وفضاء Orlicz-Lorentz و فضاء Musielak- Orlicz وغيرها . الدوال المعيارية تفتقر الى الخصائص الأساسية والمرنة التي يمتلكها دوال المعيار. لأنها دوال تفتقر الى التجانس والترابط الفرعي وبالتالي قد يكون من المدهش ان نكون قادرون على استخدام تقنيات تتضمن مراكز التقارب, الهيكل الطبيعي والتحدب المنتظم للحصول على نظريات النقطه الصامده. الغرض من هذه الورقة هو اعطاء خوارزميه تكراريه جديده مسرعة للتطبيق متعددة القيم- ذات القيمة الواحدة في فضاءات مودلر واثبات بعض النتائج حول تقاربها (ضعيف-قوي) مع نقطه صامده (او نقطه صامده مشتركه) من خلال العمل فضاءات مودلر تحقق (UUC1) وكذلك شرط  و في بعض الاحيان يتطلب العمل خاصيه أوبيل وشبه الانغلاق. الهدف من هذا البحث هو اثبات الوجود والوحدانية للنقاط الصامدة الناتجة عن التقارب الضعيف لمخطط تكراري متشعب. تم انشاء هذا المخطط من خلال خمسه خطوات تكراريه ل - دوال غير ممتدة (متعددة و احاديه) بقوه في فضاء مودلر. و  تحقق((UUC1 و شرط -. للحصول على هذه النتائج والحقائق الاخرى, نقوم بأجراء تنسيقات بين التعاريف هي التقارب الضعيف, شبه القرب, و شرط اوبيل لحاله المتتابعات المزدوجة. لاحظ أن المؤلفين قدموا دراسة سابقة حول التقارب القوي لمتتابعات مزدوجة متشعبة متضمنة نتائج مهمة, راجع المصادر
Hopf and Zero-Hopf Bifurcation of the Four-Dimensional Lotka-Volterra Systems
Authors: Mustafa Sirwan A. , Hussen Niazy H.
Published: August 2024

في هذا العمل، تم النظر في نموذج لوتكا-فولتيرا رباعي الأبعاد (4DLV) الذي يتضمن أربعة أنواع في بيئة ثابتة. ويهدف هذا البحث الى دراسة التشعبات المحلية (local bifurcations) في النظام. يحتوي هذا النظام على ست عشرة نقطة من التوازن (equilibrium point) على الأكثر. تم أخذ إحدى نقاط التوازن في الاعتبار من أجل دراسة الحلول الدورية (periodic solutions)  التي تتشعب من نقطتي توازن هوبف (Hopf) وصفر هوبف (zero-Hopf)   على التوالي. توجد خمس عائلات ذات شروط كافية على معلمات النظام التي تحتوي فيها المصفوفة الجاكوبية عند نقطة التوازن على زوج من القيم الوهمية البحتة  وقيمتين ذاتيتين (eigenvalues) غير موجبتين. إضافة الى ذلك توجد ثماني عائلات ذات شروط كافية على المعلمات التي تحتوي فيها المصفوفة الجاكوبية عند نقطة التوازن على زوج من القيم الذاتية الخيالية البحتة  وعلى الأقل احدى من القيم الذاتية الأخرى تكون صفرا. بعد ذلك، يكشف هذا البحث أن بعض أنظمة Lotka-Volterra الفرعية رباعية الأبعاد تظهر حلاً دوريًا متشعبًا من نقطة توازن هوبف وثلاثة حلول دورية متشعبة من نقطة توازن هوبف صفرية بشكل استقبالي.  تتكون طريقة حساب المتوسط بأي ترتيب لحساب الحلول الدورية من توفير الظروف الكافية لوجود الحلول الدورية في الأنظمة التفاضلية متعددة الحدود من خلال دراسة نقاط التوازن للأنظمة المتوسطة المرتبطة بها. ثم، والأداة الرئيسية المستخدمة هي نظرية المتوسط من الدرجة الأولى لحساب الحلول الدورية التي تتشعب من نقاط  هوبف  وصفر هوبف  المفردة في4DLVS . وفي النهاية تدعم النتائج النظرية التي تم الحصول عليها والتحقق منها من خلال الأمثلة العددية.
Can we Estimate a Fatigue Life for Sucker Rod Materials?
Authors: Bühler M. , Lopez E. , Pereyra M. , Oliva E.
Published: August 2024

This paper aims to discuss the behavior, focused on data distribution of fatigue life for different sucker rod grades in pure fatigue and corrosion fatigue mechanisms. Analysis of the impact from several variables and the accuracy to estimate a fatigue life.

Fatigue - and more frequently - corrosion-fatigue is a major cause of premature failures in the oil and gas industry. Various technical conditions affect fatigue life and fatigue crack growth such as the material surface condition, residual stress, bulk material properties, stress conditions (multi axial, amplitude constant or variable) and environmental influence. All these conditions lead to a stochastic (not deterministic) behavior of the component. I.e., the fatigue lives of similar components under the same conditions (loads, environment) can be significantly different.

Scatter in fatigue is an inherent characteristic of materials. The performance of a sucker rod under fatigue and corrosion fatigue conditions depends on many factors, including the environment characteristics, the material properties, and the applied stresses, giving as result a stochastic behavior.

Literature available to date on this matter suggest that statistical aspects of fatigue of material are well recognized. The sources of this scatter can be essentially different for the crack initiation period and crack growth period.

Tenaris performed extensive and abundant corrosion fatigue tests at the same stress conditions to obtain the distribution function of the fatigue life. Tests were performed in fatigue tensile testing machines equipped with enclosed chambers covering the whole surface of full-scale rod samples (1" diameter × 2 ft length).

Results of corrosion fatigue testing for particular sets of samples were analyzed under Weibull density function. Even at Lab conditions with all the testing parameters as much controlled as possible, there is a dispersion of results.

The fatigue behavior of a material, mainly in its early stages, i.e. crack initiation and growth, is governed by stochastic factors giving a particular probability distribution of failure occurrence under this phenomenon. Understanding these features provides a good tool to analyze the performance of sucker rod strings and design solutions to improve the fatigue life of components.
Innovative Electric Submersible Plunger Pump System Driven by Linear Permanent Magnet Motor as A Technological Alternative for Conventional Rod Pumps in San Joaquin Basin Wells
Authors: Ocando Jairo , Seczon Luis , Erskine Travis , Patino Ivan , Sviridov Pavel , Alvidrez Joshua , Mastro Matthew
Published: August 2024

New technology has been successfully deployed to reduce the numbers of repetitive failures in conventional rod pump systems and down production associated with failures by using an Electric Submersible Plunger Pump system (ESPP) with a Linear Permanent Magnet Motor (LPMM) in vertical and deviated wells. With this new technology, production efficiency is improved compared to conventional rod pump systems. In addition, wellsite aesthetics are enhanced, which is an important feature of this technology for urban areas. A downhole reciprocating pump is driven by LPMM which replaces a long stroke rod pump that has lower reliability based on frequent failures. The ESPP with LPMM was situated in the well to avoid free gas. The ESPP with LPMM system has achieved steady production due to a unique algorithm that controls the LPMM speed and assists with difficult operational conditions resulting from sand or gas interference. The variable speed drive (VSD) is adapted from a conventional electric submersible pump controller. The motor operating temperature is low due to intermittent loading on the motor and the idle time between each stroke. The power consumption was lower than previous rod pump systems while producing similar production rates. These power measurements show a reduction in power usage of over 50% compared to traditional rod pump systems. Currently, the ESPP with LPMM unit is operating under the initial projected parameters with no failure to date, and a second unit was recently installed in the field. Furthermore, this technology maintains high energy efficiency while eliminating potential leaks from the wellhead stuffing box with a rod string. Thus, there are no methane emissions, very low noise and low surface visual clutter during production activity. Lower cost is derived from the reduction in the number of workover interventions compared to other conventional and unconventional pumping systems.
Optimization of Oil Production Through Advanced Gas Lift Technology
Authors: Ramos M. , Khalifah M. , Almilad R. , Mishkhes A.
Published: August 2024

The paper presents a methodology for optimizing Gas lift wells, aimed at enhancing the gas injection pressure and consequently deepening the gas injection point to improve the gas lift performance.

An in-depth evaluation is performed to optimize the gas lift method, employing both simulation software and in-house developed gas lift tools. The process involves the strategic installation of Side Pocket Mandrels (SPMs) equipped with Injection Pressure Operated (IPO) valves and Venturi valves at specific depths to optimize gas injection points. The analysis also looked the impact of installation of Pressure Control Valves (PCVs) in the Gas lift pipe line networks, which in computer simulations showed potential to increase gas injection pressure. The increase in pressure enables the optimization of the gas lift wells, thereby improving well performance. The comprehensive nodal analysis and calibration pressures were applied to fine-tune the gas lift designs, considering the individual characteristics of expected targeted wells.

In the simulated scenarios, the newly evaluated methodology improves gas lift wells’ efficiency by 18%. The PCV installation and subsequent adjustments in injection pressure enables the targeting of deeper gas lift injection point, optimizing the gas lift performance and enhancing drawdown and overall well productivity. The custom-developed real-time gas lift monitoring system was pivotal in continuous performance evaluation, allowing for immediate detection and resolution of issues such as gas re-circulation and valve leaks.

This paper introduces innovative techniques and methodologies in gas lift optimization, particularly emphasizing the development and utilization of a proprietary real-time monitoring system for gas lift operations. This system represents a significant advancement in the field, enabling real-time diagnostics, troubleshooting and optimization across multiple wells. The integration of gas lift rig-less technologies is also proposed to enhance the economic viability and operational efficiency of gas lift systems. This innovation marks a significant advancement in artificial lift methods, presenting a more efficient and integrated approach to Gas Lift performance monitoring.
Design, Development and First Operation of a New Redirected Gas Lift Mandrel
Authors: Fraga R. S. , Barrionuevo D. C. , Perovano T. G. , Guerra L. A. O. , Almeida A. R. , Rodrigues H. T.
Published: August 2024

Traditionally in oil production wells that employ gas lift as an artificial lift method, the injection of lift gas is commonly performed from the annular space to the interior of the production tubing string, at a downward oriented angle (in the opposite direction to the fluid flow delivered by the reservoir). The downward gas jet causes turbulence in the flow due to the sudden changes in flow direction, precisely at the location of the gas lift mandrel, which results in a localized additional pressure drop. Optimization of the geometry responsible for the gas injection into the production tubing string consisting of changing the lift gas injection angle is a strategy aimed at achieving production gains by reducing the localized pressure drop. Theoretical mathematical analysis applied to this fluid flow problem, along with computational simulations and experimental execution, showed that, for high gas injection flow rates and/or the adoption of small diameters of the injected gas jet, it is possible to obtain a production gain at a relatively low cost by reversing the direction of lift gas injection. This paper briefly explains the process of conception, development, qualification and prototype operation of the redirected gas lift mandrel.
Observing Dynamic Well Behaviour During Gas Lift with Slickline Deployed Distributed Fiber Optic Sensing Helps Diagnose Well Performance Issues in the White Tiger Field Vietnam
Authors: Webster M. J. , Ferguson N. J. , Nguyen D. Q. , Hoang M. V. , Tran N. T. , Pham T. C. , Vu T. H.
Published: August 2024

Surveillance of dynamic well performance is problematic using conventional sensors as only one location can be observed. But during gas lift, multiple points of gas entry may be active over large distances in a well. This paper presents a case study using a Distributed Fiber Optic Sensing (DFOS) enabled Slickline to monitor the entire length of the well over the whole duration of the survey to enhance well performance diagnostics.

Conventional logs measure events local to the sensor as its pulled uphole. Many dynamic events affect the entire wellbore and can be intermittent in nature. The diameter of conventional logging tools may disturb what they try to measure or are recorded over restricted rates for safety reasons. A DFOS Slickline system was deployed in a gas lifted well to diagnose well performance. Data was recorded over the entire well for the duration of the survey flowing at conventional production rates. This data was processed at wellsite and a quicklook provided within hours of survey.

This is a case study from a gas lifted well in the White Tiger field in Vietnam. Results show the behaviour during both an annulus bleed phase and gas lift injection phase over all 7 side pocket mandrels simultaneously providing evidence showing which mandrel was faulty. The results provided clear evidence of an inefficient gas lift system with a significant reduction in drawdown with consequential loss of production. An intervention to resolve the issue resulted in a significant enhancement of the wells production. The survey provided critical information to help plan remediation and restoration of stable production resulting in an over 300% increase in oil production.

The use of slickline DFOS allowed for the continual monitoring over all gas lift valves simultaneously during kickoff and production of the well. This increased confidence in the diagnosis and remediation needed to restore production.
Successful Application of All-Metal PCP in CSS and Steam Flood to Unlock Hard-To-Recover Oil Resources
Authors: Skoczylas Paul , Sawafi Mohammed , Salem Basem Ahmed , Al Jabri Sulaiman , Zadjali Ahmed , Ponomarenko Roman
Published: August 2024

Petroleum Development Oman (PDO) operates diverse fields in Oman, facing challenges in recovering hard-to-recover oil resources characterized by high viscosity and low reservoir temperature in one of the developing fields. Despite implementing Cyclic Steam Stimulation (CSS), the wells exhibit suboptimal responsiveness to steam cycles, rendering conventional Artificial Lift Systems (ALS) ineffective due to high viscosity impact.

Following unsuccessful attempts with other ALS, the decision was made to explore All Metal Progressing Cavity Pumps (AMPCP). AMPCPs were chosen for their capability to seamlessly transition to injection of 350°C Steam through the Stator without requiring extensive workovers. Notably, AMPCP demonstrated resilience against high overloads in cold conditions, enhancing production cycles and reducing reservoir pressure, thereby improving the efficiency of steam injection cycles. The main objective of the project is to enhance the effectiveness of steam support, potentially leading to a shift from CSS to steam flood improving overall production.

Addressing these issues, All- Metal PCP Technology appears to be a reliable solution due to its durable design and ability to withstand high loads when fluid viscosity significantly increases at low temperatures. A field trial has been done to test the performance of AMPCPs in PDO's field in Oman. Out of the 15 installations conducted so far, four are operational, three are awaiting commissioning and six pulled AMPCPs have been re-qualified for re-run. The longest run life so far is 1037 days. It is worth noting that two wells have successfully transitioned to steam flood, improving efficiency of extraction method. Although there were some challenges related to scale and solids plugging, the resilience of AMPCPs has allowed for their re-installation after being operational on a test bench following rotor extraction. The PCM Metal to Metal technology has demonstrated exceptional performance within the low temperature range of 30°C – 60°C, handling viscosities up to 30000 cP in addition to high temperature application. Its ability to withstand high overloads, reaching up to 130% on PCP head loading, confirms its suitability for high-viscosity scenarios

High viscosities cause challenges such as high friction losses, overloading ALS systems and leading to infant failures and significant workover costs. The AMPCP application for unconventional oil recovery, is a proven method to produce the unconventional reservoir, when the conventional ALS methods fail.
Successful Field Trial of Well Completion with Suitable Artificial Lift in Cbm Horizontal Wells of India
Authors: Sharan S. K. , Keswani V. H.
Published: August 2024

Horizontal wells are drilled within Reliance Coalbed Methane (CBM) in India to increase productivity. This can be facilitated by reducing FBHP to a minimum. The commingled flow of gas and water causes high Gas Volume Fraction (GVF) at pump intake. Gas separators with suitable lifting systems were critical to reduce GVF. Well completion was designed with Progressive Cavity Pumps to handle the production of coal fines whilst catering to the chances of high rod-tubing wear.

(GAS HANDLER PCP) were expected to provide improved run-life in these conditions. Software simulation was used to optimize the placement of rod guides and centralizers on the rod string to minimize tubing integrity problems. The process of evaluation and optimization involved the deployment of different Well completion of AL and Gas separators with a provision for metering free gas from tubing to determine GVF. Well, operation and monitoring were optimized with the use of RPM, flow rate, and GVF. Minimum pump submergence was respected to avoid pump failure. Both PCPs and GAS HANDLER PCPs were installed to provide a run-life comparison

The results of the trial have been positive to date, and The GAS HANDLER PCP along with the designed well completion has allowed run times of the pump to increase significantly. The rod string design through Software simulation supplemented the increased run times achieved. Remarkable improvement in reducing GVF was accomplished by proper selection of gas separator. The combination of a gas separator and GAS HANDLER PCP has achieved a very low Flowing Bottom Hole Pressure (FBHP – 20 to 25 psi) for an acceptable period. After successful results from the completion of the trial, Reliance CBM has scaled up the implementation of this technology in multi-lateral CBM Horizontal wells. It has proven to be the most cost-effective method to complete and produce from a CBM horizontal well. With the substantial increase in productivity from CBM wells this technology is set to change the course of how CBM field can be developed more productively.

Work is continuing to improve the well production lifespan with the addition of a Tubing Rotator and close monitoring of tubing wear analysis. It will eliminate the cumbersome and costly hydraulic fracturing (HF) operations in coal seams with or without contrasting boundaries (shale boundary). Significant reduction in environmental hazards due to HF is an advantage, that will encourage more operators to adopt this technology. Horizontal wells in CBM will enhance the gas production output of India.
Gas Lift Optimization in the Permian Using Machine Learning and Artificial Intelligence
Authors: Movahed P. , Burmaster D. , Karantinos E. , Villarreal A. L. , Memarzadeh M. , Vela S. G. , Tapley S. C. , Newlin C. , Banes T. A.
Published: August 2024

Gas lift is among the most prevalent artificial lift methods in the Permian Basin, accounting for over 50% of total oil production. Despite that, gas lift optimization has historically been a time-consuming process, which limited optimization efforts to cases with the most significant potential for improvement. Automated gas lift optimization can add incremental volumes without the need for major OPEX/CAPEX expenditures. In this paper, we present a closed-loop iterative well-by-well Gas Lift Optimization Workflow deployed to more than 1300 ExxonMobil wells in the Permian Basin. The workflow conducts multi-rate tests via remote control of gas lift injection rate setpoints in combination with automated well data acquisition. Optimal injection rate setpoints are determined by quantifying the relationship between gas injection rate and downhole pressure, and automatically maximizing drawdown/production. This is achieved with minimal disturbance to the surface facilities network. A machine learning model provides optimization recommendations for wells without a downhole pressure gauge. Production data undergoes a rigorous quality control process to ensure that measurements are accurate and representative of current well conditions. Incremental uplift is tracked using a model-based approach based on well productivity and steady-state well tests. The optimization workflow has been applied to more than 1300 wells, with an average oil production uplift of approximately 2.0%.
Dancing above the abyss : environmental effects and dark matter signatures in inspirals into massive black holes
Authors:   , Becker Niklas
Published: August 2024

In this dissertation, we look at environmental effects in extreme and intermediate mass ratio inspirals into massive black holes. In these systems, stellar mass compact objects orbit massive black holes and lose orbital energy due to gravitational wave emission and other dissipative forces. We explore environmental interactions with dark matter spikes, stellar distributions, accretion disks, and combine and compare them. We discuss the existence and properties of dark matter spikes in the presence of these environmental effects. The signatures of the environmental effects, such as the phase space flow, dephasing, deshifting of the periapse, and alignment with accretion disks, are examined. These signatures are quantified in isolated spike systems, in dry, and in wet inspirals. We generally find dark matter effects to be subdominant to the other environmental effects, but their impact on the waveform is still observable and identifiable. Lastly, the rates of inspirals and the impact of spikes are estimated. All of these results are obtained with the help of a code imripy that is published alongside. If dark matter spikes exist, they should be observable with space-based gravitational wave observatories.
Information-theoretical analysis of EEG microstate sequences in wakefulness and sleep
Authors:   , Wiemers Milena Constanze
Published: August 2024

Microstates are short, recurring electric field topographies over the cortex. The majority of the electroencephalogram (EEG) signal variance is explained by four representative topographies, canonically known as maps A-D. Similar maps have been found in wakefulness and sleep. Microstates have been examined thoroughly during wakeful rest, but our understanding of microstates in other vigilance states is limited. Different vigilance states are usually distinguished by the EEG frequency spectrum and graphoelements, while the microstate approach focuses on the spatial distribution of the electric field at each time point. The aim of this study was to analyze the temporal structure of microstate sequences in wakefulness and sleep. Using information-theoretic methods, a direct comparison between microstate sequences and classic frequency-based EEG analysis is made possible. We present an EEG analysis of 32 healthy subjects in wakefulness and sleep in which we found an increase of the mean microstate duration and the transition matrix relaxation time with deepening sleep stages, pointing towards slower microstate dynamics in sleep. Interestingly, more than half of the sequences in deep sleep could not be distinguished from simple Markov models which can be interpreted as a decrease in sequence complexity. The entropy rate of the sequences decreased with deepening sleep stage, indicating a less random, i.e. more predictable sequence structure. Furthermore, we found that microstates occur periodically whenever the underlying EEG has a dominant frequency. This shows that oscillatory brain activity can be tracked at the microstate level, making it possible to distinguish different vigilance states quantitatively. Interpreting microstates as correlates of functional brain networks, we conclude that the same or very similar networks are activated in sleep and wakefulness, but their activation is slowed down and less complex.