Student Gestures During Shifts from Descriptions to Explanations of Gas Pressure

The Next Generation Science Standards emphasize engaging students in the practice of constructing explanations using disciplinary core ideas such as the structure of matter. Research has identified that students have difficulty both with constructing explanations and with constructing particulate views of matter, and therefore there is a need to research additional ways to support students in these areas. The present study investigated how students used gestures as they shifted from descriptions to explanations of phenomena involving gas pressure. Using case studies based on student interviews, we found that students used gestures differently when they provided descriptions and when they provided explanations. While giving descriptions, students used gestures to represent observable aspects of the phenomena. While giving explanations, students used gestures to simultaneously represent observable aspects of the phenomena and unseen mechanisms. We conclude that prompting students to use gestures while explaining phenomena may help improve the quality of their explanations by helping them link observable phenomena with underlying mechanisms.National Science Foundation under Grant No. DUE-1432424Ope

Hylleraas Variational Perturbation Theory: Application to Correlation Problems in Molecular Systems

Hylleraas variational perturbation theory is applied through second order in energy to estimate the correlation energy in several molecular systems. The specific choices for H0 and V which are made lead to equations nearly identical to the multireference linearized coupled‐cluster method of Laidig and Bartlett. The results obtained are in virtually exact agreement where comparisons have been made. Results from test calculations are presented for BeH2, CH2, and C2H4. In addition, the utility of perturbation theory for selecting correlating configurations is examined. This procedure is found to be quite accurate while significantly reducing the size of the system of linear equations to be solved

Jämförelse av skatterättsliga holdingbolagsregler - Casestudie avseende Sverige, Danmark och Nederländerna

Alla företag har en rad utgifter i sin verksamhet och företagen strävar efter att hålla kostnaderna nere. Skatter är en kostnad för företagen och man vill därför minimera dessa så mycket som möjligt. Multinationella företag har därför ett intresse av att analysera skattereglerna i olika länder innan man fattar beslut om olika strukturer för sin verksamhet. Många företag använder sig idag av så kallade holdingbolag för att göra skattebesparingar på sitt ägande. Landet som huvudkontoret är etablerat i kanske inte lämpar sig för ägande på grund av mindre förmånliga skatteregler. Därför kan det vara ett lämpligt alternativ att placera ägandet i ett holdingbolag i en skattevänlig jurisdiktion. Därtill är även andra faktorer viktiga i beslutsmaterialet vid en etablering. Bland annat är det vid holdingbolagsetablerandet intressant med låga bolagskatter, hur underkapitaliseringsreglerna ser ut, om staten i fråga har sådana samt om staten har många dubbelbeskattningsavtal. Uppsatsens syfte är att utifrån ett amerikanskt bolag stationerat i New York välja ett av tre länder där det från det amerikanska bolagets synvinkel kan vara skattemässigt mest intressant att placera ett holdingbolag utifrån ett ägande i tredje stat. Som tredje stat används Estland i denna uppsats. Vid en sådan etablering kan det även vara intressant att ta hänsyn till ländernas underkapitaliseringsregler, eftersom ett utnyttjande av förmånliga sådana regler kan innebära stora skattevinster. Förutom att utreda vilket land som totalt erbjuder de förmånligaste reglerna finns det även andra intressanta aspekter som skall belysas. Uppsatsen kommer till exempel att visa hur Sverige står sig internationellt i konkurrensen med att locka till sig koncernbolags etableringar av holdingbolag. Med det menar jag att den komparativa genomgången av ländernas regler för näringsbetingade andelar kommer att visa på vissa skillnader som kan vara viktiga i konkurrenshänseende. Vidare är även andra faktorer viktiga, till exempel till ländernas (Sverige, Danmark, Nederländerna) dubbelbeskattningsavtal med ifrågavarande lands moderbolag särskilt ifråga om regler för utdelning och källskatter. Vidare måste man även ta hänsyn till vilket tredje land holdingbolaget skall utöva ägandet i samt de beskattningsförhållanden som råder där samt eventuella källskatter som kan träffa transaktionerna från Estland till holdingbolagslandet bland annat. Sverige, Danmark och Nederländerna har alla skatteregler för näringsbetingade andelar. Av dessa följer att alla tre länderna har skattelättnader för andelar som bolag i dessa länder innehar i bolag även i andra länder. Dock är det endast Sverige som inte har några krav på ägandet ifråga om kortaste innehavstid. I övrigt finns även andra skillnader i reglerna om innehav. Eftersom Nederländerna har varit populärt val av holdingbolagsland kan det vara intressant att se hur två skandinaviska länder står sig i konkurrensen, särskilt som både Danmark och Sverige gjort sig mer konkurrenskraftiga i holdingbolagshänseende. Dubbelbeskattningsavtal träffas mellan stater av flera anledningar. Det mest betydelsefulla syftet är att de avser att förhindra att en viss inkomst beskattas två gånger. Man kan se reglerna som allokeringsregler. De allokerar inkomster till en kontraktsslutande stat. Vidare innehåller avtalen regler om maximinivåer för olika typer av inhemska skatter. Uppsatsen tar upp skatteavtalen som länderna i studien har med USA och de poster som är intressanta. I kapitel fem presenteras skatteberäkningar för utdelning som skickas från en tredje stat till vart och ett av holdingbolagsjurisdiktionerna för att sedan slussas vidare till det amerikanska moderbolaget

Toxoplasma gondii infection and common mental disorders in the Finnish general population

Objective: We investigated whether T. gondii seropositivity is associated with 12-month depressive, anxiety and alcohol use disorders and current depressive symptoms and whether inflammation, measured by C-reactive protein (CRP) level, explains these associations. Method: Health 2000 study (BRIF8901), conducted in years 2000-2001, is based on a nationally representative sample of Finns aged 30 and above, with 7112 participants and 88.6% response rate. DSM-IV depressive, anxiety and alcohol use disorders were assessed with the Composite International Diagnostic Interview and depressive symptoms with the Beck Depressive Inventory (BDI-21). We used logistic regression to investigate the association of T. gondii seropositivity with mental disorders and linear regression with BDI-21 scores. Results: T. gondii seroprevalence was significantly associated with 12-month generalized anxiety disorder but not with other anxiety, depressive or alcohol use disorders. T. gondii seropositivity was associated with higher BDI-21 scores (beta 0.56, 95% CI 0.12-1.00, P = 0.013) and with having a comorbid depressive and anxiety disorder (OR 1.86, 95% CI 1.16-2.97, P = 0.010). Higher CRP levels were associated with these outcomes and with T. gondii seropositivity, but adjusting for CRP did not change the effect of T. gondii seropositivity. Limitations: Cross-sectional study design with no information on the timing of T. gondii infection. Conclusion: T. gondii seropositivity is associated with generalized anxiety disorder, depressive symptoms and comorbid depressive and anxiety disorders, which is not mediated by inflammation.Peer reviewe

The association between toxoplasma and the psychosis continuum in a general population setting

Toxoplasma gondii infection is associated with increased risk for psychosis. However, the possible association between T. gondii and psychotic-like symptoms in the general adult population is unknown. We investigated whether T. gondii is associated with psychotic-like symptoms and psychosis diagnoses using data from Health 2000, a large cross-sectional health survey of the Finnish general population aged 30 and above. Seropositivity to toxoplasma was defined as a cutoff of 50 IU/ml of IgG antibodies. Lifetime psychotic-like symptoms were identified with section G of the Composite International Diagnostic Interview, Munich version (M-CIDI). Symptoms were considered clinically relevant if they caused distress or help-seeking or there were at least three of them. Lifetime psychotic disorders were screened from the sample and were diagnosed with DSM-IV using SCID-I interview and information from medical records. All data were available for 5906 participants. We adjusted for variables related to T. gondii seropositivity (age, gender, education, region of residence, cat ownership, and C-reactive protein measuring inflammation) in regression models. We found that T. gondii seropositivity was significantly associated with clinically relevant psychotic-like symptoms (OR 1.77, p = 0.001) and with the number of psychotic-like symptoms (IRR = 1.55, p = 0.001). The association between toxoplasma and diagnosed psychotic disorders did not reach statistical significance (OR 1.45 for schizophrenia). In a large sample representing the whole Finnish adult population, we found that serological evidence of toxoplasma infection predicted psychotic-like symptoms, independent of demographic factors and levels of C-reactive protein. Toxoplasma infection may be a risk factor for manifestation of psychotic-like symptoms. (c) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Association of cytomegalovirus and Epstein-Barr virus with cognitive functioning and risk of dementia in the general population : 11-year follow-up study

Background: Earlier studies have documented an association between cytomegalovirus and cognitive impairment, but results have been inconsistent. Few studies have investigated the association of cytomegalovirus and Epstein-Barr virus with cognitive decline longitudinally. Our aim was to examine whether cytomegalovirus and Epstein-Barr virus are associated with cognitive decline, in adults. Method: The study sample is from the Finnish Health 2000 Survey (BRIF8901, n = 7112), which is representative of the Finnish adult population. The sample was followed up after 11 years in the Health 2011 Survey. In addition, persons with dementia were identified from healthcare registers. Results: In the Finnish population aged 30 and over, the seroprevalence of cytomegalovirus was estimated to be 84% and the seroprevalence of Epstein-Barr virus 98%. Seropositivity of the viruses and antibody levels were mostly not associated with cognitive performance. In the middle-aged adult group, cytomegalovirus serointensity was associated with impaired performance in verbal learning. However, the association disappeared when corrected for multiple testing. No interactions between infection and time or between the two infections were significant when corrected for multiple testing. Seropositivity did not predict dementia diagnosis. Conclusions: The results suggest that adult levels of antibodies to cytomegalovirus and Epstein-Barr virus may not be associated with a significant decline in cognitive function or with dementia at population level. (C) 2018 Published by Elsevier Inc.Peer reviewe

Exposure to common infections and risk of suicide and self-harm : a longitudinal general population study

Common infectious agents, such as Toxoplasma gondii (T. gondii) and several human herpes viruses, have been linked to increased risk of self-harm. The aim of this study was to investigate the associations between self-harm and seropositivity to T. gondii, Epstein-Barr virus (EBV), Herpes Simplex virus Type 1 (HSV-1), and Cytomegalovirus (CMV). IgM and IgG antibodies to these infections were measured in the Health 2000 project nationally representative of the whole Finnish adult population, and 6250 participants, age 30 and over, were followed for 15 years via registers. In addition, lifetime suicidal ideation and suicide attempts based on medical records and interview were assessed within a subsample of 694 participants screened to a substudy for possible psychotic symptoms or as controls. Among the 6250 participants, 14 individuals died of suicide and an additional 4 individuals had a diagnosis of intentional self-harm during follow-up. Serological evidence of lifetime or acute infections was not found to be associated with these suicidal outcomes. However, in the subsample, those seropositive for CMV had fewer suicide attempts compared to those seronegative, adjusting for gender, age, educational level, childhood family size, regional residence, CRP, and screen status (OR for multiple attempts = 0.40, 95% confidence interval 0.20-0.83, p = 0.014). To conclude, common infections were not associated with risk of death by suicide or with self-harm diagnoses at a 15-year follow-up in the general population sample. Our finding of an increased number of suicide attempts among persons seronegative for CMV calls for further research.Peer reviewe