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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Classifying Previous Covid-19 Infection : Advanced Logistic Regression Approach / Klassifiering av tidigare Covid-19 infektion : Avancerad logistisk regressionsmetodik

Westerholm, Daniel January 2023 (has links)
The study aimed to developed a logistic model based on antibody proteins, vaccinations and demographic factors that predicts previous infection in Covid-19. The data set comprised of 2750 individuals from eldercare homes in Sweden, with four test dates executed between October of 2021 and August of 2022.  Exploratory data analysis revealed bimodal patterns in the antibodies against nucleocapsid protein within the non-infected group, raising suspicions of false negatives in the data. Due to the binary nature of the response and to be interpretable for further research, logistic regressions were used to model the relation between predictors and the logit of the response. Because of low performance scores and high probability for the presence of false negatives, K-means clustering algorithm was performed on the data. As a clustering variable, the logarithm of base 2 of the nucleocapsid protein was used, because of its theoretical relationship with previous infection in Covid-19.  Observations were reclassified using the clustering technique, and two new logistic models were fitted to the data. The final model contained polynomial terms to handle the non-linear relationship between the logit of the response and the predictors. We found a significant relationship between the logarithm of 2 of nucleocapsid protein and previous Covid-19 infection in the final model, with high prediction results. We reached an F1-score of 0.94, indicating a well-performing model.  Additionally, an algorithm was created to predict the days since infection, involving the change in nucleocapsid protein from one test date to the next, and a GAM model for fitting a smooth line to the data between nucleocapsid protein as response against the days since infection. Using this algorithm, we reached an absolute mean error between predicted results and actual days since infection of 23 days. This algorithm was later applied to observations reclassified in the clustering process.  In conclusion, the study successfully reclassified false negative observations with previous Covid-19 infection, and fitted a logistic model with high prediction score with F1-score of 0.94. Finally, an algorithm was created that estimated the days since infection with an absolute mean error of 23 days. / Syftet med studien var att utveckla en logistisk modell baserad på antikroppsproteiner, vaccinationer och demografiska faktorer som förutsäger tidigare infektion i Covid-19. Datamängden bestod av 2750 individer från äldreboenden i Sverige, med fyra testdatum utförda mellan oktober 2021 och augusti 2022.  Utforskande dataanalys visade på bimodala mönster i antikroppar mot nukleokapsidprotein inom den icke- infekterade gruppen, vilket gav upphov till misstankar om falskt negativa resultat i datamaterialet. På grund av svarets binära karaktär och för att vara tolkningsbara för vidare forskning användes logistiska regressioner för att modellera förhållandet mellan prediktorer och responsvariabeln. På grund av låga prediktionsresultat och hög sannolikhet av förekomsten av falskt negativa svar utfördes K-means-klusteralgoritmen på datat. Som klustervariabel användes logaritmen av bas 2 för nukleokapsidproteinet, på grund av dess teoretiska samband med tidigare infektion i Covid-19.  Observationerna omklassificerades med hjälp av klustertekniken, och två nya logistiska modeller anpassades till datat. Den slutliga modellen innehöll polynomiala termer för att hantera det icke-linjära förhållandet mellan responsens logit och prediktorerna. Vi fann ett signifikant samband mellan logaritmen av 2 av nuk- leokapsidprotein och tidigare Covid-19-infektion i den slutliga modellen, med ett högt prediktionsresultat. Vi nådde en F1-score på 0.94.  Dessutom skapades en algoritm som predicerade dagar sedan infektion med hjälp av förändringen i nukleokap- sidprotein från ett testdatum till nästa, och en GAM-modell för att anpassa ett glidande medelvärdeslinje till datat mellan nukleokapsidprotein som response mot dagarna sedan infektionen. Med hjälp av denna algoritm nåddes ett absolut medelfel på 23 dagar mellan prediktion och faktiskt tid sedan infektionen. Denna algoritm tillämpades senare på observationer som omklassificerats i klusterprocessen.  Sammanfattningsvis lyckades studien framgångsrikt omklassificera falskt negativa observationer med tidigare Covid-19-infektion och anpassade en logistisk modell med hög prediktionspoäng med en F1-score på 0.94. Slutligen skapades en algoritm som uppskattade dagarna sedan infektionen med ett absolut medelfel på 23 dagar.
182

Effect of the COVID-19 Pandemic on Dental Anxiety and Oral Health Related Quality of Life

Weyman, Alissa January 2023 (has links)
Objective- To determine the impact of the COVID-19 pandemic on dental anxiety (DA) and oral health related quality of life (OHRQoL) proxy measures using electronic dental records from Temple University Kornberg School of Dentistry (TUKSoD). Methods- A cross-sectional study comparing data before the COVID-19 Pandemic (G1) (N=4,516) and before (G2) (N=3,995) and after the vaccine was available (G3) (N=3,891) was analyzed for patients 18 and older. The independent variables are age, sex, race, diabetic status, hypertension status, and DA. The dependent variable – OHRQoL – has four components (trouble while chewing, speaking, embarrassment due to dental problems, and pain/ sensitivity) which were converted to a composite score for analysis. OHRQoL, were coded as good, fair, and poor. Mann-Whitney U tests were used to assess outcome differences across the three groups. Statistical significance was set at p<0.05. Results- The proportion of individuals with poor DA in G1, G2, and G3 were about 5%, 3%, and 4% respectively. The proportion of individuals with poor OHRQoL were 8%, 5%, and 4% in G1, G2, and G3, respectively. About 26%, 21%, 19% reported poor social interactions in G1, G2, and G3, respectively. About 1% of individuals in G1, G2, and G3 reported poor speaking. About 8%, 3%, and 5% reported poor chewing in G1, G2, and G3, respectively. About 4% of individuals in G1 and 3% in both G2 and G3 reported poor comfort. Significant differences in DA were observed between G1 vs G2 (p=<0.01) and G1 vs G3 (p=<0.01). Also, significant differences in OHRQoL between G1 vs G2 (p=<0.01), G2 vs G3 (p=0.01), and G1 vs G3 (p-value=<0.01). Associations between DA and OHRQoL were seen across G1, G2, and G3. Hypertension and diabetic status also seemed to be associated with OHRQoL at multiple points in this study. Conclusion- Overall, OHRQoL and dental anxiety improved post COVID-19 vaccine availability compared to the pre-COVID-19 vaccine availability and the pre-COVID-19 pandemic. This could be attributed to increased health consciousness triggered by the COVID-19 events. / Oral Biology
183

Inskränkningar i fri-och rättigheter under covid-19 pandemin : - är grundlagen ändamålsenlig för att hantera fredstida kriser? / Restrictions on freedoms and rights during the covid-19 pandemic : - is the Swedish constitution fit for purpose to handle crises in peacetime?

Pavlos, Cavelier Bizas January 2022 (has links)
No description available.
184

Examining the associations of physical activity, resiliency, mental health, and heart rate variability in graduate students during a pandemic / Physical activity, resiliency, mental health, and heart rate variability in graduate students during a pandemic

Marashi, Maryam January 2021 (has links)
Introduction: The COVID-19 pandemic has resulted in higher-than-normal levels of anxiety and depression, especially among graduate students whose academic trajectory was disrupted. Physical activity and trait resiliency have both been shown to protect against stress-induced anxiety and depression during the pandemic. However, it remains unknown whether the same was true for graduate students and what biological mechanism, such as heart rate variability (HRV) might underpin these relationships. Method: We examined change in stress, current physical activity, and trait resiliency to identify key factors associated with better mental health outcomes in a national sample of graduate students (N = 61) who were recruited during the COVID-19 pandemic. We evaluated the unique contributions of change in graduate-school-related stress, physical activity (moderate, vigorous, and fitness), and trait resiliency to both anxiety and depression. We conducted moderation analyses to explore the processes through which these variables interact and mediation analyses to examine whether HRV was part of the underlying mechanism. Questionnaire were used to assess graduate-school-related stress, physical activity (moderate, vigorous), and trait resiliency. We estimated physical fitness using the six-minute walk test and captured resting HRV using a validated mobile application. Results: Graduate students reporting greater change in school-related stress were more anxious and depressed; however, those who engaged in more moderate physical activity were less anxious and those with higher trait resiliency were less anxious and depressed. Moderation analyses revealed a “stress threshold” for moderate physical activity whereby students who were more physically active were more protected from anxiety symptoms than their lower active peers; but this was only true for people whose stress levels increased a little or moderately but not for people whose stress levels increased a lot. In contrast, trait resiliency was shown to buffer against depression regardless of change in stress level. HRV did not mediate these relationships. Conclusion: Graduate students experienced significant mental strain during the COVID-19 pandemic, but physical activity and trait resiliency may be promising protective factors. / Thesis / Master of Science in Kinesiology
185

Valor predictivo de la hipocalcemia en el diagnóstico de la insuficiencia respiratoria aguda en COVID-19 en un hospital de segundo nivel de atención / Predictive value of hypocalcemia in the diagnosis of acute respiratory failure in COVID-19 in a second-level care hospital

Santana-Téllez, Tomás Noel, Rojas- García, Milton, Del Águila-Grández, Angie Yohana 10 December 2021 (has links)
Objetivo. Demostrar la validez de la hipocalcemia para predecir la gravedad de la insuficiencia respiratoria en pacientes con COVID-19. Materiales y métodos. Estudio tipo cohorte prospectivo, en 267 pacientes hospitalizados en la Unidad de Cuidados Intermedios del Hospital II EsSalud Pucallpa, entre enero y junio de 2021. Se extrajeron datos demográficos, clínicos y laboratoriales de las historias clínicas individuales. Se utilizó análisis multivariado para identificar las variables asociadas a la insuficiencia respiratoria aguda. Resultados. De los 267 pacientes, el 61 % tuvo hipocalcemia al ingreso. En este grupo predominaron la tos seca, fatiga y dolor torácico; la fiebre y la disnea en la totalidad de los pacientes. La principal comorbilidad fue la obesidad.Tanto la frecuencia respiratoria  30 rpm como la SaO2  93 % fueron más frecuentes en este grupo. Hubo relación inversa entre la hipocalcemia y la elevación de ciertos parámetros considerados marcadores inflamatorios; además de una mayor tasa de PaFiO2 anormal. Se constató una buena concordancia entre la hipocalcemia y los resultados de la PaFiO2 (índice Kappa de Cohen = 0,63). Conclusiones. La hipocalcemia puede considerarse un factor predictor de insuficiencia respiratoria grave en pacientes con COVID-19.
186

Características morfológicas de las médulas óseas en pacientes con infección por Sars-Cov2 del Hospital 2 de Mayo, Perú / Morphological characteristics of bone marrows in patients with SARS-CoV-2 infection from Hospital 2 de Mayo, Peru

Pichardo-Rodríguez, Rafael, Peña-Oscuvilca, Willy, Diaz-Robles, David, Mendoza-Sánchez, Dennise, Carrasco-Vergaray, Carlos, García-Perdomo, Herney Andrés, Ruiz-Franco, Oscar 14 December 2021 (has links)
Introducción: A nivel medular, el SARS-COV2 puede comprometer la hematopoyesis, manifestándose con citopenias y solo se cuenta con estudios realizados en autopsias. Objetivo: describir las características morfológicas de las médulas óseas de los pacientes hospitalizados por neumonía por COVID-19 en el Hospital Nacional “Dos de Mayo”. El estudio: Estudio transversal retrospectivo llevado a cabo en pacientes con diagnóstico de COVID-19. Las lecturas de las médulas óseas fueron confirmadas por un hematólogo entrenado. Se utilizó estadística descriptiva para las variables cuantitativa y cualitativas. Hallazgos: Se incluyeron 30 pacientes. Los hallazgos más frecuentes fueron: macrófagos con citofagocitosis (87%), hiperplasia con detención en la maduración de los progenitores mieloides en el (70%). El 87% de las muestras presentó eosinofilia. En el 57% de las muestras se observó ninguna o poca evidencia de formación plaquetaria. En el 40% se encontró 6% de células plasmáticas. Conclusión: La infección por SARS-COV2 puede generar alteraciones medulares.
187

Síntomas gastrointestinales como manifestaciones extrapulmonares en pacientes con COVID-19. Una revisión narrativa / Gastrointestinal symptoms as extrapulmonary manifestations in patients with COVID-19. A narrative review

Sánchez-Toro, Vivian, Vásquez-Tirado, Gustavo Adolfo, Meregildo-Rodríguez, Edinson Dante, Segura-Plasencia, Niler Manuel, Arbaiza-Avalos, Yessenia Katherin, Serna-Alarcón, Víctor 22 December 2021 (has links)
Introducción: La infección por SARS-CoV-2 afecta principalmente el sistema respiratorio; pero, también se han observado múltiples manifestaciones extrapulmonares en diversos sistemas y órganos. Las células epiteliales del tubo digestivo y árbol hepatobiliar expresan ECA2 y TMPRSS2 necesarios para el ingreso viral, por otro lado, el ARN viral ha sido detectado en muestras de heces, incluso después de haberse negativizado en muestras respiratorias. La presencia de manifestaciones clínicas digestivas se asocia a mayor carga viral y en ocasiones pueden ser las únicas manifestaciones de COVID-19, incluso en ausencia de síntomas respiratorios. Los síntomas más comunes son anorexia y diarrea, náuseas, vómitos y dolor abdominal, siendo este último característico de pacientes gravemente enfermos. Es muy poco frecuente la presencia de hemorragia gastrointestinal, colitis hemorrágica o hepatitis aguda. Ante un paciente con manifestaciones gastrointestinales debe considerarse a COVID-19 dentro del diagnóstico diferencial.
188

Is there any role of intermittent fasting in the prevention and improving clinical outcomes of COVID-19?: intersection between inflammation, mTOR pathway, autophagy and calorie restriction

Gnoni, Martin, Beas, Renato, Vásquez-Garagatti, Raúl 01 December 2021 (has links)
The coronavirus disease 2019 (COVID-19) pandemic is provoking a global public health crisis. Even though the academic world is intensively pursuing new therapies, there is still no “game changer” in the management of COVID 19. The Mammalian Target of Rapamycin (mTOR) is an ancient signaling system that has been proposed as a molecular tool used by coronaviruses and other RNA and DNA viruses in order to replicate and persist in the host cell. In recent years, Intermittent Fasting (IF), a practice consisting on a strict calorie restriction during a prolonged period of time during the day, has gained popularity due to its potential benefits in multiple health systems and in regulating inflammation. IF inhibits the mTOR pathway which is similar to the effects of Rapamycin in some animal models. mTOR inhibition and promotion of autophagy could potentially be the link between the possible direct benefits of IF in COVID-19 due to the interruption of the viral cycle (protein synthesis). Besides, IF has shown to be a strong anti-inflammatory in multiple prior studies, and may play a role in attenuating COVID -19 severity. This review hypothesizes the possible intersection between viral, immunological, and metabolic pathways related to mTOR and the potential mechanisms through which IF may improve clinical outcomes. Future prospective randomized controlled clinical trials to evaluate intermittent fasting (IF) regimens in order to prevent and treat moderate to severe forms of COVID-19 in humans are needed. / Revisión por pares
189

Intention to vaccinate against COVID-19 in Peruvian older adults

Caycho-Rodríguez, Tomás, Carbajal-León, Carlos, Vivanco-Vidal, Andrea, Saroli-Araníbar, Daniela 01 July 2021 (has links)
Con los recientes acuerdos del gobierno peruano con los laboratorios Sinopharm, Pfizer y Astrazeneca para la adquisición de vacunas contra la COVID-19, surge la pregunta de si un número suficiente de personas estarían dispuestas a ser inmunizadas para controlar la pandemia y la manera de garantizar que la población esté adecuadamente informada sobre la vacuna1.
190

Is a greater extent of nature visits associated with better well-being during the Covid-19 pandemic?

Brorsson, Ieva January 2022 (has links)
The Coronavirus disease-2019 (COVID-19) pandemic has affected countries all over the world and impacted many areas of our lives. Research studying psychosocial issues caused by Covid-19 addressed that during the pandemic well-being was lower. Well-being integrates mental health, clinical and developmental theories to provide a better understanding of positive psychological functioning. An abundance of studies demonstrated that natural environments, both wild and managed, have a positive effect on people’s being. In the present study, the changes in people’s nature visits as well as the links between nature visits and well-being has been investigated. The current sample (1902 participants) was from the corona survey, a subsample of the SLOSH. During the Covid-19 pandemic, some people started visiting nature more, while others reduced their visits. Well-being was lower than before. The observed directions of the associations were: nature visits were positively linked with the quality of life, while depressive moods from 2020 and 2021 were linked negatively. Change in forest visits (&lt;65 female group) was the best well-being predictor from all types of nature exposure.

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