bluuebunny/crossref_metadata_2025 huggingface dataset:
The Health-Economic Impact of a Prospectively Validated Severity of Illness Predictor for Adult Critical Care
Authors: Kramer Andrew , Kane-Gill Sandra , Dasta Joseph , Maurer Paula
Published: September 2024

Background: The ViSIG system, a clinical decision support system for adult intensive care units, was previously shown to be associated with significant reductions in length of stay, readmissions, and duration of mechanical ventilation. However, the health-economic benefits of ViSIG have yet to be fully understood. Infections and acute kidney injury are two measures of clinical significance with key financial implications, and their reduction could further strengthen the published association of ViSIG use with improved outcomes. Further, it is important to demonstrate the economic benefit of ViSIG for its widespread adoption by ICUs. Objective: To investigate the potential health-economic benefits associated with using a previously validated clinical decision support system, ViSIG. Study Design and Methods: In this study, we analyzed data from a previous analysis of ViSIG. The study cohort consisted of six ICUs at two hospitals, with a total of 2,256 admissions in the 'Blinded' Phase and 1,890 admissions in the 'Visible' Phase. We compared the frequency of new infections and Acute Kidney Injury (AKI) between the two phases and used multivariable mixed models to adjust for each patient’s severity of illness. To estimate the economic benefit of ViSIG, we calculated the mean total charges per patient for each phase and the change in patient throughput to arrive at a net gain/loss annual total charges per bed. Results: In the Visible Phase, infections declined by 40.5% (p<0.001). When adjusted for patient severity of illness, the Visible Phase had an odds ratio of 0.52 (95% confidence interval = 0.43, 0.62). There was a 24.5% relative decrease in the occurrence of AKI (p<0.001) and a 35% adjusted decrease from Blinded to Visible Phase (p<0.001). The mean total charges were $59,886 and $55,821 for the Blinded and Visible Phases, respectively. However, due to a reduced ICULOS in the Visible Phase, there was a 14.2% increase in admissions during the 90-day period. This resulted in an estimated mean increased revenue of $3,872 per patient at ICUs using ViSIG. Conclusion: ViSIG was associated with a reduction in two major clinical events: new infections and progression to AKI. This lessened clinical burden may be associated with reduced ICULOS, which resulted in increased patient throughput and, thus, increased revenues. Future studies need to measure specific clinician actions to characterize a cause-and-effect relationship.
What Do Suicides, Heart Attacks and COVID-19 Deaths Have in Common?
Authors: Gandal Keith , Gandal Neil
Published: September 2024

In this paper, we examine U.S. COVID-19 deaths by day of the week during the first few months of the pandemic. Using data from the two large US. States (Florida and Texas) that report deaths by “day of actual death,” and controlling for time trends, we show that deaths during the Monday to Friday period (the week) were 7-8 percent higher than the weekend (Saturday and Sunday) in these states. The weekend effect does not obtain in New York City, which also reports deaths by “day of actual death.” We provide some preliminary thoughts as to why this “weekend” effect obtains for COVID-19 deaths in Florida and Texas, but not in New York City. We then compare the strength of the weekend effect for COVID-19 with suicides and heart attacks since both of these have a social component and exhibit a “day of the week” effect.
Primary health reforms in China since the New Healthcare Reform: Policy, Practice, and Progress
Authors: Xiao Yue , Zhang Yanchun , Zhang Lifang , Morton Alec , Qin Jiangmei , Lin Chunmei
Published: September 2024

In 2009, China launched a new round of radical healthcare system reforms, with primary health as a key area. Great progress and good outcomes have been made in promoting primary health which have helped to form the typical model and experience of primary health in China in its current development stage. Based on literature analysis and case study, this paper reviewed the history of primary health care in China since the latest round of healthcare system reforms, summarized the practices and outcomes of initiating institutional reforms, enhancing health capacity, improving care delivery, and building the system, so as to provide some experiences for the international comparison. In the face of the new situation of population aging and changes in the spectrum of diseases, China's primary health care is still facing problems and challenges such as unbalanced development, weak service capacity, weak talent team, and the lack of a hierarchical diagnosis and treatment system. Considering the actual situation of primary health in China and looking ahead, next step five areas need be reinforced.
Measuring Dementia Symptoms: Using the Mini-Mental State Examination as a Surrogate for the Clinical Dementia Rating Scale when Evaluating Dementia Interventions
Authors: Brent Brent
Published: September 2024

Abstract Background: Recently, a number of non-pharmacological interventions for dementia symptoms were evaluated using Cost-Benefit Analysis and found to be both effective and socially worthwhile. In these studies, dementia symptoms were measured by the Clinical Dementia Rating (CDR) scale. Although the CDR is the most comprehensive and reliable instrument for measuring dementia symptoms, common practice is to use the Mini-Mental State Examination (MMSE) as a substitute. The objective of this paper is to examine the relationship between the two measures, using a large national data set, in order that one can meaningfully convert evaluations using the MMSE into the more comprehensive CDR version. Methods: The main analysis involves using regression models to estimate the relationship between the two dementia symptom methods in a large, national, panel data set. Four regression specifications are presented according to which controls are selected. The subsequent analysis entails looking at a case study of a particular dementia intervention, that of vision correction, to see whether in practice the MMSE and CDR give similar CBA decisions results when data on both measures were actually available. Results: We find that multiplying a MMSE outcome measure by 0.4 will provide a valid approximation for the CDR when the latter measure is not available. This approximation was reasonably robust to a whole range of controls that were included. The case study of vision correction provided further corroborative evidence that the MMSE can be a practical surrogate for the CDR. Conclusions: The CDR can be approximated by the MMSE when carrying out a CBA of any dementia symptoms intervention. Benefits estimated using the CDR can readily be transferable to become the benefits using the MMSE.
A Comparative Analysis of Hypofractionated and Conventional Radiotherapy for Breast Cancer Patients: A Retrospective Cohort Study
Authors: Mallum Abba , Tendwa Maureen , Balogun Onyinye , Akudugu John , Ngwa Wilfred , Vorster Mariza
Published: September 2024

Breast cancer presents a substantial health challenge in Africa and marked by a continuous rise in its incidence and prevalence. The complexities of managing breast cancer on the continent are exacerbated by limited access to healthcare resources and high rates of late-stage disease at initial diagnosis. Recent studies comparing hypofractionated radiotherapy (HFRT), considered cost-effective and non-inferior to conventional fractionated radiotherapy (CFRT), have shown no significant differences in outcomes. This underscores the potential significance of HFRT in breast cancer treatment. Despite encouraging findings from researchers in developing countries, there is a noticeable lack of data on HFRT outcomes, particularly in Sub-Saharan Africa. This retrospective study analyzed individuals diagnosed with early, locally advanced or oligometastatic cancer, and who underwent treatment between January 2010 and December 2020 at Inkosi Albert Luthuli Central Hospital in the KwaZulu Natal Province of South Africa. Relevant clinical treatment details and follow-up information were retrieved from the patients' medical electronic records. This retrospective study included 645 breast cancer patients, categorized into early (37.7%), locally advanced (59.9%), and oligometastatic (2.4%) stages. Treatment modalities included surgery (100%), chemotherapy (77.8%), endocrine therapy (38.8%), and targeted therapy (4.8%). All patients received radiotherapy, with a predominant utilization of HFRT (83.7%) over CFRT (16.3%). Notably, there was no statistically significant difference (p=0.91) observed in survival probability between patients who received HFRT and CFRT. The findings of this study suggest that, in a low-income setting, HFRT does not exhibit a significant variance in survival outcomes compared to CFRT for breast cancer patients. However, to validate this conclusion, additional large-scale randomized clinical trials are imperative.
What do you get? Transmission of pneumococcal pneumonia.
Authors: Boom Tom , Budinská Anna , Šeligová Júlia , Rijkers Ger
Published: September 2024

Streptococcus pneumoniae is a polysaccharide encapsulated bacterium responsible for the majority of cases of community acquired pneumonia. The upper respiratory tract of children becomes colonized with pneumococci early in life, from the first weeks of life up to 18 months. Factors which influence timing of colonization include geographical localization, socio-economic circumstances, and household conditions. Pneumococcal pneumonia to a degree is a seasonal disease, peaking in the winter months. One of the epidemiological determinants is that viral infections (in particular influenza) predispose for pneumococcal pneumonia. The infectious nature of pneumococcal pneumonia was underscored during the COVID-19 pandemic. Due to societal restrictions imposed (face masks, social distancing) the incidence of invasive pneumococcal disease (IPD) dropped, and returned to pre-COVID-19 numbers after lifting of the restrictions. There are 100 different S. pneumoniae serotypes, based on differences in the capsular polysaccharide. Introduction of protein conjugated polysaccharide vaccines (PCV) has reduced the incidence of IPD in children. Because children are the reservoir for other risk groups, in particular the elderly, introduction of PCV has indirectly also reduced the burden of IPD in latter risk group. The first generation of PCV consisted of the seven most prevalent pneumococcal serotypes. After implementation, replacement colonization of the upper respiratory tract with non-vaccine serotypes was observed and also replacement disease. Upcoming 24-valent PCVs will have a much broader coverage, but whether replacement disease now has been eliminated remains to be seen.
Pretibial Myxedema in a Hypothyroid Patient with Grave’s Disease: A Case Report
Authors: Tserendorj Munkhtsetseg , Bavuu Oyunbileg , Boldbaatar Ankhlan , Tumenbayar Bayasgalan , Sonomtseren Sainbileg
Published: September 2024

Pretibial myxedema, a rare dermatological manifestation primarily associated with Graves' disease, presents as nonpitting edema, nodular, or plaque-like lesions on the lower legs due to accumulation of hyaluronic acid. We present the case of a 42-year-old woman with a history of Graves' disease who developed dark plaques and indurated skin lesions on her shins, extending to the dorsal feet. Diagnosed with Grave’s disease 20 years prior, she underwent subtotal thyroidectomy following antithyroid treatment. Pretibial myxedema developed one-year post-thyroidectomy and was managed with systemic glucocorticoids. She later received iodine-131 therapy, which led to hypothyroidism, and started to admit thyroid hormone replacement. The thyroid function test revealed normal TSH levels and increased TRAbs. Histopathology of skin lesions showed mucopolysaccharide deposition and increased collagen confirming myxedema. This case highlights the rare elephantiasis form of pretibial myxedema and underscores the importance of recognizing characteristic skin lesions in patients with hypothyroidism.
No hubo cortes en Toledo en tiempos del "Lazarillo"
Authors: Cáseda Teresa Jesús Fernando
Published: September 2024

A lo largo de este estudio se intenta dar una solución a los dos principales “problemas” para la comprensión del Lazarillo. En primer lugar, la datación. El autor emplea una vieja estrategia de ocultación y sitúa en el pasado –mediante la mención a las cortes de Carlos V en Toledo– hechos que, sin embargo, son posteriores. Y, en segundo lugar, esta investigación identifica la causa de la escritura de la obra: la aprobación del Estatuto de limpieza de sangre de la catedral de Toledo de su arzobispo Juan Martínez Silíceo en 1547. De este modo ni las cortes de 1525 ni las de trece años después –1538-1539– sirven para establecer su cronología porque ambas son anteriores a los hechos novelados. Asimismo, el autor oculta bajo la máscara de personajes a individuos reales relacionados en todos los casos con Silíceo, el verdadero “Lázaro de Tormes” o protagonista de la novela.
Effect of ethical leadership and performance evaluation on transfer price prediction: A social learning experiment
Authors: Wiharsianti Ervilia Agustine , Nisa' Fitria Sarifatun
Published: September 2024

Research aims: This paper investigates two control mechanisms that firms can use to avoid negotiation conflicts in negotiated transfer pricing decisions.Design/Methodology/Approach: This experimental research used a 2x2 factorial design between subjects. This study involved 77 undergraduate economics and business students as participants. Research findings: This result revealed that divisions evaluated with systems that value high ethical leadership and competitive performance evaluation schemes would set transfer prices close to equal profit transfer prices. These results suggest that companies with individual performance evaluations in a decentralized corporate structure can use informal controls such as ethical leadership to manage negotiation conflicts.Theoretical contribution/ Originality: This study provides further knowledge to the ethical leadership literature by examining the influence of ethical leadership and performance evaluation schemes on transfer pricing. Previous research on leadership and transfer pricing prediction is limited and primarily focuses on tone leadership. This research, therefore, develops previous research by focusing on another leadership style, namely ethical leadership, with an experimental design.Practitioner/Policy implication: This research provides an easy and low-cost alternative control mechanism to reduce conflicts that can occur in the transfer price negotiation process.Research limitation/Implication: This research is limited to ethical leadership styles and limited transfer pricing mechanisms. Future research, thus, can use other leadership styles and other transfer pricing mechanisms, such as two-step pricing. Different mechanisms used can produce different decisions as well.
Los objetos de metal de Tamtoc y Rancho Aserradero: Un análisis morfológico y de composición
Authors: Schulze Niklas , Ruvalcaba Sil José Luis
Published: September 2024

Se presenta un primer estudio de un conjunto de 52 piezas metálicas de cobre y oro procedentes de los sitios arqueológicos de Tamtoc y de Rancho Aserradero, ambos ubicados en la Huasteca Potosina. Los objetos son utilitarios (agujas, anzuelos y hachas) y ornamentales (anillos, cuentas y cascabeles). El objetivo de este artículo es describir los objetos, presentar el análisis de composición realizado con un equipo de fluorescencia de rayos X de manera no invasiva in situ, reconstruir los procesos de elaboración y llevar a cabo una comparación con objetos de otras regiones Mesoamericanas contemporáneas. Lo anterior con el fin de profundizar en el conocimiento sobre el uso de metales y sus aleaciones en la región Huasteca, conocer sobre las decisiones culturales que pudieron influenciar su manufactura y obtener información sobre las redes de intercambio de este tipo de artefactos. El resultado del examen de 52 piezas analizadas señala una gran heterogeneidad (morfológica y de composición elemental), lo que limita las interpretaciones culturales por el tamaño de la muestra. No obstante, se infiere que estos sitios tenían acceso a una extensa red de intercambio al contar con objetos procedentes del centro y occidente de México, así como de la región de Oaxaca y/o de Centroamérica.
Análisis de residuos orgánicos en botijas coloniales recuperadas durante las excavaciones del Proyecto Templo Mayor en el Centro Histórico de la Ciudad de México
Authors: Pecci Alessandra , Mileto Simona , Islas Orozco Mirsa , López Luján Leonardo
Published: September 2024

Esta investigación parte del interés por definir el contenido de recipientes cerámicos españoles usados por siglos como envases de productos agrícolas que eran exportados de España a sus colonias americanas. Para ello hemos analizado una serie de fragmentos de botijas que se encontraron en los niveles estratigráficos coloniales del Centro Histórico de la Ciudad de México. Se trata de 10 muestras recuperadas en el marco de las excavaciones arqueológicas del Proyecto Templo Mayor del Instituto Nacional de Antropología e Historia. Los resultados obtenidos nos han permitido establecer que el contenido de estas botijas no siempre fue el mismo. Identificamos la presencia, muchas veces combinada, de productos de origen vegetal (probablemente aceites y vinos principalmente), aunque en ciertos casos también había productos de origen animal. Por el momento, no hemos podido definir cuál era el contenido preferente de cada uno de estos recipientes y cuál fue la secuencia en los productos envasados. Destaca el hecho que logramos corroborar que es posible analizar cerámicas vidriadas, obteniendo de ellas información clave que servirá a futuro para definir el uso de los recipientes del periodo colonial novohispano.
Cocina e identidad de un grupo doméstico de estrato intermedio en Sihó, Yucatán. Análisis químicos semicuantitativos y extracción de gránulos de almidón en cerámica y obsidiana
Authors: Novelo Pérez María J. , Fernández Souza Lilia , Herrera Parra E. Moisés
Published: September 2024

La alimentación y la cocina se encuentran íntimamente ligadas a la vida cotidiana y a la identidad de las sociedades. En este artículo se explora las prácticas culinarias de un grupo doméstico de estrato intermedio en el asentamiento maya prehispánico de Sihó, Yucatán. Se llevó a cabo análisis químicos semicuantitativos de fragmentos cerámicos, así como la recuperación y análisis de gránulos de almidón en cerámica y en navajillas prismáticas de obsidiana de un contexto de cocina del conjunto habitacional 5D72. Entre los resultados destacan la identificación de gránulos de almidón de camote (Ipomea batatas), chile (Capsicum sp.), maíz (Zea mays) y probablemente cacao (c.f. Theobroma cacao), los cuales fueron extraídos de ollas, cuencos y vasos. Algunos gránulos de almidón presentaron daños por procesos culinarios como molienda y cocción. Con base a lo anterior se plantean los posibles alimentos preparados, servidos y consumidos en el conjunto residencial. Se analiza el acceso a bienes alimentarios del grupo doméstico y se comparan estos mismos tópicos en los conjuntos elitarios del asentamiento. De esta manera, se discuten algunos aspectos identitarios de los habitantes del conjunto 5D72 y su relación con otros grupos domésticos de Sihó.
Espectrometría infrarroja y datación arqueomagnética de un horno de cal en la periferia de Dzibilchaltún, Mérida, Yucatán
Authors: Ortiz-Ruiz Soledad , García-Ruiz Rafael , Goguitchaichvili Avto , de Lucio Oscar G. , Murguía Salazar Jaziel Aldair , Vernet Tarragó Eva , Góngora Salas Ángel , Bautista-Zuñiga Francisco , Morales-Contreras Juan Julio
Published: September 2024

En años recientes la exploración de los hornos para cal en la península de Yucatán ha sido parte recurrente en los trabajos arqueológicos; durante el Salvamento Arqueológico, cerca de Chaactun, se halla un horno que presentaba abundante concreción de un material blanco que se denominó cal, durante las excavaciones se llevó a cabo el muestreo arqueométrico y arqueomagnético con la finalidad de corroborar los hallazgos arqueológicos. La conjunción de los resultados permitió estudiar desde todos los ángulos esta estructura y definir el momento de quema de cal, el momento de abandono y su afectación durante la reutilización del predio como rancho ganadero. Estos resultados nos indican la importancia de realizar ambos muestreos con la finalidad de integrar los resultados a la discusión teórica y metodológica del uso de estructuras de combustión en el área Maya.
Análisis de residuos orgánicos aplicados a metates y pocitos del sitio Presa de la Luz, Jalisco
Authors: Fienco Cuadrado Francisco Aníbal , Esparza López Juan Rodrigo , Coria Téllez Ana V. , May Crespo José Fernando , Novillo Verdugo Miguel
Published: September 2024

El presente artículo tiene como espacio de estudio el sitio arqueológico Presa de la Luz (600 d.C.-1000 d.C.). Ubicado en Jalisco, México. Este sitio se caracteriza por la presencia de una diversidad de manifestaciones gráfico-rupestres (MGR), tanto en superficie como debajo de ella. Aquí, las actividades antrópicas han sido constantes y evidentes, lo que ha generado una modificación significativa de los vestigios arqueológicos. Este escenario es propicio para realizar estudios arqueológicos que permitan comprender las dinámicas sociales y culturales en la región. Se han llevado a cabo estudios previos principalmente registros y descripciones, sin embargo, no se ha profundizado en la interpretación sobre el uso y la funcionalidad que cumplían estas manifestaciones en el pasado. En este sentido, el objetivo de investigación fue analizar las MGR del sitio arqueológico como indicadores de apropiación espacial y determinar el uso y la funcionalidad de estos dispositivos, utilizando una metodología de carácter multidisciplinar, con la incorporación de datos provenientes del registro material, de los elementos naturales y del análisis químico de materialidades. Como resultados se obtuvo la identificación de gránulos de almidones en metates y pocitos (presentan características de fijeza), de forma particular, gránulos de maíz y frijol. Palabras clave: molienda, paisaje, residuos orgánicos, rupestre.
¿Qué contenían las vasijas Capacha? Un análisis exploratorio por medio de residuos químicos
Authors: Zacarías Salcedo Héctor Mizraim , Ortiz Butrón Agustín , Hernández Grajales Meztli , Padilla Gutiérrez Eliseo Francisco
Published: September 2024

El desarrollo cultural Capacha se ubicó en el Valle de Colima a finales del Preclásico Temprano y principios del Preclásico Medio. Este es uno de los grupos humanos más enigmáticos del Occidente de México a consecuencia de que no conocemos contextos más allá de sus ofrendas funerarias, ricas en materiales cerámicos. Es por ello que para este trabajo se realizó el análisis de residuos químicos mediante spot tests de 50 vasijas Capacha de 11 formas distintas, todas ellas recuperadas por Kelly en las décadas de 1960 y 1970, y resguardadas en el Museo Nacional de Antropología de la Ciudad de México. Los resultados mostraron que posiblemente en gran parte de los recipientes se ofrendaron alimentos ricos en proteínas correspondientes a una variedad de caldos, bebidas y guisos. La forma, tamaño y residuos en algunas vasijas indicaron que pudieron servir para ofrendar sangre.
La producción de cerámica después del proceso de abandono de Monte Albán, Oaxaca: el caso del sector Atzompa
Authors: Cervantes-Solano Miguel A. , Robles García Nelly M. , Cejudo Rubén , Goguitchaichvili Avto , Martínez Martínez Yazmín Janeth , Galván Benítez Miguel Ángel , Morales Juan
Published: September 2024

Durante la temporada 2010 del Proyecto Arqueológico Conjunto Monumental de Atzompa, componente urbano de Monte Albán, fue encontrado un horno en un área de producción de cerámica dentro de un contexto doméstico auxiliar o de servicios en la residencia llamada Casa de los Altares. En el año 2019 fue descubierto otro horno con características similares en las inmediaciones de la Casa de Sur. Estos hornos tienen características y dimensiones muy similares a los de la tradición etnográfica de Atzompa y, de acuerdo con el contexto arqueológico, se interpreta que fueron utilizados durante su última etapa para la elaboración de grandes ollas de cerámica gris. Al tratarse de estructuras de combustión encontradas in situ, los hornos cumplían con las condiciones para ser estudiados con fines de datación arqueomagnética. En este trabajo se reportan los resultados del estudio arqueomagnético realizado en el horno localizado en la Casa del Sur del sitio de Atzompa. La temporalidad encontrada sitúa el momento del último uso del horno en una época posterior a la que comúnmente se acepta como la edad de abandono de Monte Albán y de sus conjuntos monumentales. Este nuevo resultado plantea la hipótesis hasta ahora poco explorada de que los habitantes de Atzompa habrían continuado realizando quemas rituales reutilizando el antiguo horno, o bien que regresaron al sitio después del colapso para hacer uso de la infraestructura para fabricar cerámica con fines comerciales.
STUDY OF THE DYNAMICS OF SPINDLE SHAFT ON GAS-STATIC BEARINGS
Authors: Breshev Oleksii , Nosko Pavlo , Bashta Oleksandr , Bashta Alla , Radko Maksym
Published: September 2024

This study delves into the complex dynamics of spindle shafts mounted on gas-static bearings, employing computational experiments and analysis to reveal crucial insights for optimizing high-precision machining processes. We identify natural frequencies and resonant tendencies of spindle vibrations through advanced Finite Element Method (FEM) simulations, highlighting their impact on operational stability and machining quality. Deliberately introduced imbalances further illuminate the dynamic behavior, displaying the detrimental effects of resonance on spindle performance. To mitigate these effects, we explore various technical solutions, including reducing rotor imbalances and intensifying acceleration through critical regions. Ultimately, this investigation provides a comprehensive understanding of spindle dynamics on gas-static bearings, guiding the development of robust and high-precision spindles for a range of industrial applications beyond just machining, such as precision robotics and microfabrication.
ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ ТЕХНОЛОГІЧНИХ ПРОЦЕСІВ ВОЛОЧІННЯ І ПРОКАТКИ В УМОВАХ РАЦІОНАЛЬНОГО ВИКОРИСТАННЯ СИЛ СУХОГО І НАПІВРІДИННОГО ТЕРТЯ ПІД ВПЛИВОМ ЗОВНІШНІХ ВІБРАЦІЙ
Authors: Маліновський  Юрій , Даниліна Галина , Власенков Дмитро , Рибак Дмитро , Олійник  Світлана
Published: September 2024

У сучасних технологічних процесах з обробки металів тиском, таких як холодна прокатка, накатка і волочіння, значна частка енергії, що підводиться до прокатного пристрою, безповоротно втрачається на тертя та зношування, а також надання заготівлі заданої форми (або розмірів) у результаті пластичної деформації.
Для оцінки характеру тертя в таких машинах визначено види фрикційної взаємодії матеріалу оброблюваної заготовки з інструментом, з урахуванням впливу мастильних матеріалів. Як було встановлено, під час обробки металів тиском, має місце як «сухе», так і «напіврідинне» тертя. Навіть за наявності мастила в кінематичній парі: волока-дротяна заготовки переважає сухе тертя. Як показує практика – виникнення значних сил тертя і сил натягу заготовки зумовлено наявністю множинних деформаційних мікронерівностей у приймальній частині волоки, під час її взаємодії з рухомою заготовкою. Ці мікронерівності (на заготівлі) зрізаються і пластично деформуються під час взаємодії контактної пари. Причому цей деформаційний процес супроводжується безперервним хвильовим фоном у звуковому діапазоні.
Для інтенсифікації процесів прокатування і волочіння рекомендовано використовувати, за аналогією з вібраційною обробкою металів різанням, вібраційне прокатування і волочіння, шляхом встановлення на застосовуваних волоках додаткових вібраторів, які діють у напрямі прокатки або волочіння. Пропоновані вібратори працюють, як правило, в ультразонах. Оптимізація роботи прокатної (волочильної) установки здійснюється шляхом підбору амплітуди і частоти додаткової вібрації, що забезпечують необхідний режим роботи машини, який реалізує перехід від «сухого» тертя між дротом і фільєрою до «напіврідинного» тертя.
Впровадження заходів зі створення додаткових пристроїв для ультразвукового волочіння і прокатки дає змогу знизити енергетичні витрати на виконання операції прокатки і волочіння, а також підвищити зносостійкість інструменту.
СТАДІЇ НАГРІВАННЯ І ОХОЛОДЖЕННЯ ПАР ТЕРТЯ ГАЛЬМІВНИХ ПРИСТРОЇВ
Authors: Вольченко  Дмитро , Кіндрачук Мирослав , Дем'янчук Ярослав , Возний  Андрій , Бурава  Олександр , Присяжний Андрій , Ніщук Віктор
Published: September 2024

Теоретичні та експериментальні дослідження енергонавантаженості різних типів фрикційних вузлів гальм при імпульсному і тривалому режимах гальмування дозволили визначити поверхневий і глибинний градієнти температури, а також темпи нагрівання і вимушеного повітряного охолодження фрикційних елементів і при цьому встановлено: найбільш поширеним при локальному контакті виникаючих полях ліній струмів є термодинамічний потенціал, що включає в себе зовнішні і внутрішні параметри в їх робочих шарах; термо-динамічний потенціал визначається умовами термодинамічної рівноваги трибосистеми і критеріями її стійкості в багатьох процесах, що супроводжуються зміною енергії; локальна ділянка фактичного контакту мікровиступів, утворена одночасною дією нормальних і тангенціальних імпульсних навантажень, що викликають електричні та теплові струми, що не повністю зникають при знятті імпульсних питомих навантажень, формуючи фрикційні зв'язки мікровиступів; величини поверхневих і глибинних температурних градієнтів та їх обмеження для металічних фрикційних елементів, а також темпи нагрівання та охолодження, знання яких дозволяють перейти до закономірностей зміни теплофізичних параметрів матеріалів пар тертя.
The nonlinear phenomena in vacuum microelectronic structures
Authors:   Moscow Insitute of Electronics and Mathematics of National Research University ", Solntsev Viktor ,   Higher School of Economics"
Published: September 2024

The results of researches of physical processes in vacuum microelectronics structures with matrixes field emission of cathodes (FEA) are given. A number of theory methods, nonlinear phenomena and structures known earlier and offered recently are considered: calculation of harmonics of a current and decision of the equations of a electrons movements in structures with modulation of emission, microwave diode with FEA, high-frequency field emission contact, BWO with auto modulation of emission (carcinotrode), fractal fieid emission the cathode. The general approaches to construction of the analytical and numerical theory of devices with modulation of emission are developed. The classification of modes of operations of the diode with FEA is given and the complete picture of behavior of efficiency and electronic conductivity of the diode with FEA in modes without cutoff and with the current cutoff is received; the limiting efficiency makes 30-40 %. The influence of heterogeneity of а field at the cathode is considered. The opportunity of existence of the high-frequency field emission contact between two conductors is shown with absence of а static field, the characteristic distinguished from the F-N law is found. The nonlinear theory of BWO with automodulation of emission by a field of a return wave is offered and the opportunity of essential increase of efficiency from 15 % in usual BWO up to 35 % in carcinotrode is shown with the conservation of electronic tuning of the frequency. The opportunity of the further increase of efficiency in the isophase carcinotrode up to 60-70% is аlso shown. For getting of the limiting characteristics of considered structures fractal field emission cathodes with the special form of а surface are offered, the possibility of essential gain of an electrical field on tips and increase of а current for the limited voltage from such cathodes is shown.
Dynamics of an off-axis gaussian beam with astigmatism and twist in a transparent nonlinear waveguide medium
Authors:   Yuri Gagarin State Technical University of Saratov, Melnikov Leonid , Derbov Vladimir ,   Saratov State University, Bychenkov Alexei ,   Saratov State University
Published: September 2024

Using the modified generalized moments method the equations of motion are derived for the parameters of а misaligned astigmatic twisted Gaussian beam in an axially symmetric nonlinear medium. Nontrivial features of the beam dynamics (e.g., phase locking, cycle generation, nonlinear symmetry change) in a parabolic waveguide with Kerr nonlinearity are revealed.
Arnold’s cat map: quantum chaos and operator dynamics in Heisenberg representation
Authors:   Saratov Branch of Kotel`nikov Institute of Radiophysics and Electronics of Russian Academy of Sciences, Kuznetsov Sergey
Published: September 2024

The quantum model system is considered for which the classic analog is the known Arnold’s саг map. Due to periodicity conditions for the phase space, quantum states are represented by vectors of finite dimension N, and operators by NxN matrices. The integer parameter N characterizes a relative value of quantum effects; classic limit corresponds to N—>∞. Operator тар is suggested which governs discrete time evolution in Heisenberg representation for operators of finite shifts for position and momentum. Explicit form of evolution operator is stated in Schrodinger representation. Solution for non—stationary problem is presented and discussed for initial conditions taken as localized state, two delta—spikes, Gaussian wave packet. Quantum dynamics in terms of Husimi distribution and Wigner function, quasi—cnergy spectrum and eigenvector structure are discussed on а basis of dynamics of Heisenberg operators.
Information transport in active electronic fibers. Part II. the fiber as «reaction-diffusion» system
Authors:   Institute of Applied Physics of the Russian Academy of Sciences, Kazantsev Viktor , Nekorkin Vladimir ,   Institute of Applied Physics of the Russian Academy of Sciences
Published: September 2024

In this part we consider the active electronic fiber composed of resisiively coupled Chua's circuits as а discrete three-species «reaction-diffusion» systern. The dynamics of instabilities of the travelling pulses and effects of their inferactions and studied. It is shown that the fiber can display both typical for «reaction-diffusion» sysiem and quite new dynamical characteristics.
For the sake of «mankind’s education»: to the history of the university foundation in Saratov
Authors:   Saratov State University, Solomonov Vladimir
Published: September 2024

The article is devoted to the period, preceding official opening of the university in Saratov. Chronologically it ranges from the end of the 50s (19th Century), when the idea of foundation a university arose among progressively thinking intellectuals of Saratov, closely connected with N.G.Tchernishevsky, till the elaboration and final approval of the bill about its foundation in the highest governmental departments in 1909.
Via computer screen into the world of nonlinear dynamics
Authors:   Saratov Branch of Kotel`nikov Institute of Radiophysics and Electronics of Russian Academy of Sciences, Kuznetsov Aleksandr
Published: September 2024

A series of computer problems is presented covering the course «Dynamical systems and bifurcations» for students specialized in Nonlinear Dynamics. Examples of computer illustrations are given.
The conceptual basis of Japanese modern political economy: “Flying Wild Geese” paradigm
Authors:   Saratov State University, Cheremisinov Georgy A.
Published: September 2024

Introduction. The successful historical experience of modernizing Japanese economy, which managed to become one of the world economy leaders, found theoretical and methodological justification in the “Flying Wild Geese” paradigm formulated by K. Akamatsu. Scientific review. The introduction of a wide range of readers to the concept of uneven economic growth in advanced and developing countries occurred after the publication of K. Akamatsu’s articles in English in the 1960s. The methodology of the Japanese scientist was influenced by his studying German philosophic and economic thought. The “Flying Wild Geese” paradigm was built on the basis of the long wave of economic conjuncture theory by the Russian economist N. D. Kondratiev and included three models. The first model described the following sequence: import – domestic production – export. The second model explained the transition of production from consumer goods to capital goods and from simple and unprocessed products to complex and processed products. The third model showed the hierarchy of countries in the world economy in accordance with the stages of economic growth. Economic development is encouraged by contradictions and takes place in the form of the alternating emergence and resolution of contradictions of supply and demand. Industrial innovations create a contradiction in the comparative cost structure of national economies and stimulate the growth of international trade. The spread of innovations eliminates the resulting contradiction and slows down economic development. The main contradictions of development, cyclical dynamics and structural shifts correspond to the policy of progressive development, cyclical stabilization policy and structural coordination policy. Conclusion. The conducted research has shown the theoretical and methodological origins and foundations of modern economic thought in Japan.
Methods for diagnostics and forecasting SMEs creditworthiness using artificial intelligence
Authors:   Peoples’ Friendship University of Russia named after Patrice Lumumba, Kuban State University, Zabolotskaya Victoria V.
Published: September 2024

Introduction. The impact of multidirectional external macroeconomic and regional factors of the economic environment in conditions of uncertainty and increased risks causes significant difficulties in diagnosing, assessing and forecasting the creditworthiness of financial and credit support recipients and borrowers (micro, small and medium-sized enterprises) in the Russian Federation. Theoretical analysis. The author systematized the basic mathematical methods and models for assessing and forecasting the level of creditworthiness of micro, small and medium-sized businesses in foreign and Russian practice, using modern systems and technologies of artificial intelligence and machine learning methods. Empirical analysis. The author proposed the results of approbation of methodological approach for express diagnostics of the financial and economic condition and forecasting the creditworthiness of SMEs in the Krasnodar krai for the period of 2014–2017, based on expert assessment methods, economic analysis and fuzzy logic systems, which form the credit rating of SMEs considering their industry affiliation. Results. In this study, the author has determined the advantages and disadvantages of methods and models for diagnosing creditworthiness and credit scoring from the perspective of their application for various categories of SMEs. As it is shown that the most promising and mathematically reliable models for credit scoring and risk assessment of financial support and lending to various enterprises in the SME sector at different stages of their life cycle both in Russia and abroad are computerized models and expert systems, based on such methods and technologies of Artificial Intelligence, as fuzzy logic systems, artificial neural networks, support vector machines, ensemble methods (random forest method), as well as intelligent information systems, hybrid models and hybrid systems. The study reveals that their combination with each other will allow to achieve synergistic and system effects in the interaction between lenders and borrowers (SMEs) and timely avoid their bankruptcy.
Genetic Characteristics of Echinococcus granulosus from Fixed Paraffin-Embedded Tissue Samples in Human Isolates Based on the High-Resolution Melting Point Analysis in Sabzevar, Northeast Iran
Authors: Elyasi Hossein , Farbodnia Tahmine , Javaheri Ehsan
Published: September 2024

Background: There are ten genotypes of Echinococcus granulosus with different intermediate and final hosts affecting the parasite's life cycle and its transmission to humans. Therefore, this study was conducted to determine the genotype of isolated hydatid cysts using the simple and fast high-resolution melting point analysis (HRM) method.
Methods: The paraffin tissue samples of patients who underwent surgery were obtained from the pathology sample bank of Vasei and Emdad Hospitals in Sabzevar, Iran during 2010-2020. The DNA content of the samples was extracted after collecting and determining the characteristics using the DNA extraction kit. PCR was performed on the samples and the presence of the hydatid cyst genome was confirmed using the special Master Kit. Mix PCR of Solis Biodyne Company and Real-Time device (Bio-Rad) were used, and the genetic identity of hydatid cysts were determined.
Results: Out of 33 paraffin samples, 21 samples contained hydatid cyst DNA, two of which were from the brain and 19 from the liver tissues; 12 samples did not contain hydatid cyst DNAs. All liver samples were from sheep species (G1), and the brain samples were from buffalo species (G3). Therefore, 9.53% of the Echinococcus species collected were buffalo (G3), and 90.47% were sheep (G1) strain.
Conclusion: Based on previous patterns, HRM methods can be used for easy and quick identification of Echinococcus strains. The G1 strain was the dominant strain causing hydatid cyst in different human organs, including the liver and brain.
Effectiveness of Miltefosine Nanoemulsion Concerning the Treatment of Acute and Chronic Toxoplasmosis: In Vivo Study
Authors: Valizadeh Gholam Reza , Mahboubian Mohammad Mahdi , Maghsoud Amir Hossein , Mirzaei Fatemeh , Motavalli Haghi Seyedmousa , Foroughi Parvar Faezeh , Fallah Mohammad
Published: September 2024

Background: Toxoplasma gondii is one of the most common parasites worldwide. It is of great importance to identify new potential drugs that are effective and less harmful in pregnant women and newborns. We investigated nanoemulsion miltefosine (NEM) in treating experimental acute and chronic toxoplasmosis.
Methods: A combination of triacetin, Tween 80, and ethanol (1:2) was used for the development of NEM formulations. The size of NEM was calculated to be 17.463 nm by DLS and TEM. To investigate the performance of miltefosine (MLF), NEM, sulfadiazine (SDZ), and pyrimethamine (PYR) (positive control) in vivo, acute toxoplasmosis was induced in mice by an intraperitoneal injection of RH strain tachyzoites. After five days, the mice were examined for the number and condition of tachyzoites and histopathological changes in the liver and spleen. Chronic toxoplasmosis was investigated in rats and the number and size of brain cysts along with histopathological changes were assessed in different groups.
Results: The results of the in vivo assessment of drugs in acute toxoplasmosis showed the following order regarding a decrease in the number of tachyzoites and an increase in survival rate: SDZ&PYR > NEM > MLF. The effects of drugs on chronic toxoplasmosis showed a significant effect of NEM (50%) on reducing the number of cysts compared to SDZ&PYR (10%) and MLF (12%) and reducing the size of NEM brain cysts (21%) compared to SDZ&PYR (5 %) and MLF (8%).
Conclusion: Increasing the penetration of NEM through the blood-brain barrier (BBB) and subsequently reducing the number and size of T. gondii tissue cysts is a promising new drug in treating chronic toxoplasmosis.
Challenges in Supervised and Unsupervised Learning: A Comprehensive Overview
Authors: Almuqati Mohammed Tuays , Sidi Fatimah , Rum Siti Nurulain Mohd , Zolkepli Maslina , Ishak Iskandar
Published: September 2024

Data science and machine learning are at the forefront of modern technological advancements, promising automated insights, predictions, and decision-making. Supervised and unsupervised learning are pivotal paradigms within this dynamic landscape, each presenting its unique challenges. This article provides a comprehensive overview of the multifaceted challenges inherent to both supervised and unsupervised learning. This article reviews research studies published between 2019 and 2023. This article discusses the challenges of supervised and unsupervised learning. In supervised learning, challenges include data labeling, overfitting, limited generalization, and balancing mistake equivalence and decision-making goals. In unsupervised learning, difficulties encompass issues like overfitting, choosing the appropriate algorithm, and interpreting results. This includes evaluating the quality of clustering, deciding the optimal number of clusters, and managing noise and outliers. The article aims to provide insights into these challenges, enhancing the understanding of machine learning for both novices and experts. Researchers and practitioners constantly evolve their methods and tools to overcome these complexities. This article is a valuable reference for researchers and experts in the field, empowering them to navigate these challenges confidently. As technology advances, a thorough understanding of these challenges is essential for unlocking the full potential of these powerful tools. Finally, several recommendations were given to guide future researchers in applying machine learning in the journey of data-driven discovery and automation, offering challenges and opportunities for those who embark on it.
Komplementarna eksploatacja ciepła geotermalnego i gazu ziemnego ze złóż w schyłkowej fazie produkcji
Authors:   Instytut Nafty i Gazu – Państwowy Instytut Badawczy, Falkowicz Sławomir , Urbaniec Andrzej ,   Instytut Nafty i Gazu – Państwowy Instytut Badawczy
Published: September 2024

Wzrastające w ostatnich latach zainteresowanie odnawialnymi źródłami energii sprawia, że pozyskanie ciepła geotermalnego jest obecnie jednym z bardziej istotnych celów, uwzględnionych w politykach surowcowych wielu krajów Europy. Energia geotermalna uznawana jest za najbardziej stabilną pod względem parametrów energetycznych w długim okresie, a jednocześnie za najbardziej bezpieczną dla środowiska. Eksploatacja ciepła geotermalnego w reżimie dubletu wymaga znacznych nakładów inwestycyjnych na wykonanie i uzbrojenie odwiertów. Wykorzystanie do tego celu złóż gazu ziemnego będących w schyłkowej fazie eksploatacji stanowi optymalne rozwiązanie, pozwalające uniknąć znacznych nakładów ponoszonych na wykonanie prac przygotowawczych oraz odwiercenie i uzbrojenie nowych odwiertów, ale również z uwagi na często duży potencjał geotermalny poziomów skał zbiornikowych nasyconych solankami, które podścielają złoża gazu ziemnego. Generalnie zakłada się wykorzystanie zastanej sytuacji złożowej i infrastrukturalnej, jak też opracowanie najbardziej optymalnego w tej sytuacji sposobu eksploatacji ciepła, przy założeniu jednoczesnego wzrostu współczynnika sczerpania złoża gazu. W ramach tej pracy obliczono potencjał energetyczny (tj. moc geotermalną i produkcję gazu) dla pięciu wybranych horyzontów złożowych w przykładowych odwiertach gazowych. Następnie wykonano szacunkowe obliczenia przychodów możliwych do uzyskania w analizowanych przykładach odwiertów, zakładając prowadzenie jednoczesnej produkcji gazu i energii geotermalnej. Wyniki analizy danych geologicznych i złożowych wskazują, że właściwie w każdym przypadku konieczne jest wykonanie dodatkowej perforacji wytypowanych interwałów nasyconych wodami złożowymi oraz cechujących się najbardziej korzystnymi parametrami eksploatacyjnymi. Ponadto przedstawiono kryteria preselekcji odwiertów do eksploatacji gazu i energii geotermalnej na podstawie analizy mechanizmu dopływu wody do odwiertu. W pierwszej kolejności powinny być rozpatrywane odwierty, w których mechanizm dopływu wody określono jako stożek 3D. Wstępna kalkulacja parametrów eksploatacyjnych dla wybranych odwiertów wskazuje na ich potencjał komercyjny, zwłaszcza w przypadku wykorzystania do dystrybucji ciepła magazynów mobilnych.