The Topos-theoretical Approach to Quantum Physics

I oppgaven tas det sikte på å anvende begreper og metoder fra kategoriteori og især toposteori innen kvantefysikken. I den resulterende teorien, "toposfysikk", brukes toposteori (teorien om generaliserte mengdeuniverser og generaliserte rom) som et verktøy for å konstruere kvantefysikken ved å "lime sammen" klassiske perspektiver eller "snapshots". Første kapitel gir den nødvendige bakgrunn for å forstå den fysiske motivasjonen bak konstruksjonene i de påfølgende kapitler, med særlig oppmerksomhet viet emnene logikk, kvantisering og rom. I kapitel 2 presenteres først elementær teori om kategorier og topoi. Det gis deretter en gjennomgang av toposfysikkens sentrale trekk: konstruksjonen av et tilstandsrom for kvantemekanikken ved hjelp av (kovariante eller kontravariante) funktorer over en kategori av kommutative operatoralgebraer. To ulike tilnærmingsmåter, Andreas Döring og Chris Ishams "neorealisme" og Chris Heunen, Nicolas P. Landsmaan og Bas Spitters "Bohrifikasjon" presenteres i detalj. I kapitel 3 anvendes den sistnevnte tilnærmingen på teorien om "loop quantum gravity" (LQG). Kapitelet har derfor en kort oppsummering av hovedresultatene innen LQG. Det undersøkes hvordan LQG kan interpreteres innen toposfysikk ved å ta i bruk Christian Fleischhacks formulering av LQG som en Weylalgebra. De topologiske egenskapene til tilstandsrommet i LQG innen toposmodellen undersøkes, og det vises hvordan kravene til gauge- og diffeomorfiinvarians kan interpreteres i teorien. Endelig, ved hjelp av Ishams teknikk for å kvantisere generelle strukturer, utvides den toposfysiske modellen til å inkludere et bredere kategoriteoretisk rammeverk. Vi definerer en målteori for kategorier og undersøker teoriens byggesteiner, pilfeltene over en kategori, i kategorien av deres representasjoner. Vi antyder hvordan modellen kan anvendes innen Sorkins teori om kausale mengder, og som basis for en teori om kvantisert logikk

Associations between Mental Health, Lifestyle Factors and Worries about Climate Change in Norwegian Adolescents

Climate change is a serious global health threat that has an impact on young people’s lives and may influence their mental health. Since the global climate strike movement, many adolescents have expressed worries about climate change. Thus, the aim of this study is to examine the prevalence of worries about climate change, and factors associated with worries about climate change, in a representative sample of Norwegian adolescents. Data were retrieved from Ungdata, an annual nationwide online youth survey. Adolescents (n = 128,484) from lower and upper secondary school participated in the study. Data were analyzed descriptively and with logistic regression. Most of the adolescents were not worried or a little worried about climate change. Girls, pupils who had at least one parent with higher education and pupils from urban areas were more inclined to worry about the climate. Adolescents who worried about the climate had more symptoms of depression than those who were less worried. While worry about climate change may constitute an additional burden for adolescents experiencing depressive symptoms, such worry can also be seen to reflect climate-friendly values.publishedVersio

Associations between exposure to sexual abuse, substance use, adverse health outcomes, and use of youth health services among Norwegian adolescents

Background A strong association between sexual abuse and adverse health outcomes has been reported among adolescents. The present study aimed to provide more information about adverse health outcomes associated with sexual abuse and substance use, and to examine the use of youth health services among Norwegian adolescents. Methods National representative cross-sectional study among 16–19-year-old Norwegian adolescents (n = 9784). Multivariable regression analyses, adjusted for socioeconomic status and age, were used to examine the association between exposure to sexual abuse, substance use and health risk factors, and the use of youth health services. Results Adolescents exposed to sexual abuse had higher odds of depressive symptoms (males: OR:3.8; 95% CI:2.5–5.8, females: 2.9;2.4–3.5), daily headache (males: 5.3;2.8–10.1, females:1.9; 1.5–2.4), high medication use (males: 3.2;1.7-6.0, females: 2.0;1.6–2.6), self-harm (males: 3.8;2.4-6.0, females:3.2; 2.6–3.9), suicidal thoughts (males: 3.3; 2.2-5.0, females:3.0; 2.5–3.6) and suicide attempts (males: 9.5;5.6–16.0, females:3.6;2.7–4.9). Furthermore, exposure to sexual abuse was associated with higher odds of using school health services (males: 3.9;2.6–5.9, females: 1.6;1.3–1.9) and health services for youth (males: 4.8;3.1–7.6, females: 2.1;1.7–2.5). In general, substance use was associated with increased odds of adverse health related outcomes and use of youth health services, but the strength of the relationships varied according to sex. Finally, results indicated a significant interaction between sexual abuse and smoking that was associated with increased odds of having suicidal thoughts for males (2.6;1.1–6.5) but a decreased odds of having suicidal thoughts and have conducted suicide attempts once or more for females (0.6;0.4-1.0 and 0.5;0.3–0.9, respectively). Conclusions The present study confirmed a strong relationship between exposure to sexual abuse and health risks, especially among males. Moreover, males exposed to sexual abuse were much more likely to use youth health services compared to sexually abused females. Substance use was also associated with adverse health outcomes and use of youth health services, and interactions between sexual abuse and smoking seemed to influence risk of suicidal thoughts and attempts differently according to sex. Results from this study increase knowledge about possible health related effects of sexual abuse which should be used to identify victims and provide targeted treatment by youth health services.publishedVersio

Sexual harassment exposure among junior high school students in Norway: prevalence and associated factors

BackgroundSexual harassment is common in most countries and cultures. Less is known about sexual harassment, its risk factors, and psychosocial outcomes among young adolescents. The aim of the study was to examine the 12-month prevalence of sexual harassment exposure, and sociodemographic and psychosocial factors associated with exposure among junior high school students in Norway.MethodsA comprehensive cross-sectional study was completed by 83,297 Norwegian adolescents in junior high school in 2021. Data on exposure to sexual harassment were used in combination with sociodemographic measures and psychosocial outcomes: depressive symptoms, loneliness, self-esteem, and well-being. Group differences were analyzed with Chi Square tests, and sociodemographic risk factors were analyzed with logistic regression. Psychosocial outcomes were assessed with multivariate and univariate ANOVAs, and dose–response relationships were assessed with linear regression.ResultsAmong the adolescents, 32.6% had experienced sexual harassment during the past year. Girls had higher odds of exposure (OR: 1.90, 95% CI: 1.84–1.96), whereas adolescents whose parents had higher education had lower odds (OR: 0.95, 95% CI: 0.90–0.99). Exposure was associated with higher levels of depressive symptoms (partial η2 [ES] = 0.11) and loneliness (ES = 0.07), and with lower self-esteem (ES = 0.06) and well-being (ES = 0.06). Among exposed adolescents, more frequent exposure was associated with poorer outcomes.ConclusionExposure to sexual harassment affects one third of junior high school students in Norway. Those who are exposed have poorer psychosocial outcomes, and there is a dose–response relationship between exposure and outcomes. Awareness of sexual harassment among young adolescents, and interventions to prevent and reduce it, are needed

A Topos Model for Loop Quantum Gravity 1. The Topos-theoretical Approach to Quantum Physics 1.1. The Neo-realism of Döring and Isham

Abstract One of the main motivations behind so-called topos physics, as developed by Chris Isham and Andreas Döring July 30th, 2011 1. The Topos-theoretical Approach to Quantum Physics The Neo-realism of Döring and Isham In a series of articles The physically meaningful (real) value r is not a value of the physical quantity before the measurement is made. The interpretation breaks down for closed systems where no "outside" observer is to be found, such as quantum cosmology. In the topos scheme suggested by Isham and Döring, physical quantities does have a value independent of an

Associations between Mental Health, Lifestyle Factors and Worries about Climate Change in Norwegian Adolescents

Climate change is a serious global health threat that has an impact on young people’s lives and may influence their mental health. Since the global climate strike movement, many adolescents have expressed worries about climate change. Thus, the aim of this study is to examine the prevalence of worries about climate change, and factors associated with worries about climate change, in a representative sample of Norwegian adolescents. Data were retrieved from Ungdata, an annual nationwide online youth survey. Adolescents (n = 128,484) from lower and upper secondary school participated in the study. Data were analyzed descriptively and with logistic regression. Most of the adolescents were not worried or a little worried about climate change. Girls, pupils who had at least one parent with higher education and pupils from urban areas were more inclined to worry about the climate. Adolescents who worried about the climate had more symptoms of depression than those who were less worried. While worry about climate change may constitute an additional burden for adolescents experiencing depressive symptoms, such worry can also be seen to reflect climate-friendly values

Data_Sheet_1_Sexual harassment exposure among junior high school students in Norway: prevalence and associated factors.PDF

BackgroundSexual harassment is common in most countries and cultures. Less is known about sexual harassment, its risk factors, and psychosocial outcomes among young adolescents. The aim of the study was to examine the 12-month prevalence of sexual harassment exposure, and sociodemographic and psychosocial factors associated with exposure among junior high school students in Norway.MethodsA comprehensive cross-sectional study was completed by 83,297 Norwegian adolescents in junior high school in 2021. Data on exposure to sexual harassment were used in combination with sociodemographic measures and psychosocial outcomes: depressive symptoms, loneliness, self-esteem, and well-being. Group differences were analyzed with Chi Square tests, and sociodemographic risk factors were analyzed with logistic regression. Psychosocial outcomes were assessed with multivariate and univariate ANOVAs, and dose–response relationships were assessed with linear regression.ResultsAmong the adolescents, 32.6% had experienced sexual harassment during the past year. Girls had higher odds of exposure (OR: 1.90, 95% CI: 1.84–1.96), whereas adolescents whose parents had higher education had lower odds (OR: 0.95, 95% CI: 0.90–0.99). Exposure was associated with higher levels of depressive symptoms (partial η2 [ES] = 0.11) and loneliness (ES = 0.07), and with lower self-esteem (ES = 0.06) and well-being (ES = 0.06). Among exposed adolescents, more frequent exposure was associated with poorer outcomes.ConclusionExposure to sexual harassment affects one third of junior high school students in Norway. Those who are exposed have poorer psychosocial outcomes, and there is a dose–response relationship between exposure and outcomes. Awareness of sexual harassment among young adolescents, and interventions to prevent and reduce it, are needed.</p