Aerodynamics and motor control of ultrasonic vocalizations for social communication in mice and rats.

BACKGROUND: Rodent ultrasonic vocalizations (USVs) are crucial to their social communication and a widely used translational tool for linking gene mutations to behavior. To maximize the causal interpretation of experimental treatments, we need to understand how neural control affects USV production. However, both the aerodynamics of USV production and its neural control remain poorly understood. RESULTS: Here, we test three intralaryngeal whistle mechanisms-the wall and alar edge impingement, and shallow cavity tone-by combining in vitro larynx physiology and individual-based 3D airway reconstructions with fluid dynamics simulations. Our results show that in the mouse and rat larynx, USVs are produced by a glottal jet impinging on the thyroid inner wall. Furthermore, we implemented an empirically based motor control model that predicts motor gesture trajectories of USV call types. CONCLUSIONS: Our results identify wall impingement as the aerodynamic mechanism of USV production in rats and mice. Furthermore, our empirically based motor control model shows that both neural and anatomical components contribute to USV production, which suggests that changes in strain specific USVs or USV changes in disease models can result from both altered motor programs and laryngeal geometry. Our work provides a quantitative neuromechanical framework to evaluate the contributions of brain and body in shaping USVs and a first step in linking descending motor control to USV production

Adherence to a Mediterranean diet is associated with a lower risk of later-onset Crohn's disease:Results from two large prospective cohort studies

Objective: To examine the relationship between Mediterranean diet and risk of later-onset Crohn's disease (CD) or ulcerative colitis (UC). Design: We conducted a prospective cohort study of 83 147 participants (age range: 45-79 years) enrolled in the Cohort of Swedish Men and Swedish Mammography Cohort. A validated food frequency questionnaire was used to calculate an adherence score to a modified Mediterranean diet (mMED) at baseline in 1997. Incident diagnoses of CD and UC were ascertained from the Swedish Patient Register. We used Cox proportional hazards modelling to calculate HRs and 95% CI. Results: Through December of 2017, we confirmed 164 incident cases of CD and 395 incident cases of UC with an average follow-up of 17 years. Higher mMED score was associated with a lower risk of CD (Ptrend=0.03) but not UC (Ptrend=0.61). Compared with participants in the lowest category of mMED score (0-2), there was a statistically significant lower risk of CD (HR=0.42, 95% CI 0.22 to 0.80) but not UC (HR=1.08, 95% CI 0.74 to 1.58). These associations were not modified by age, sex, education level, body mass index or smoking (all Pinteraction >0.30). The prevalence of poor adherence to a Mediterranean diet (mMED score=0-2) was 27% in our cohorts, conferring a population attributable risk of 12% for later-onset CD. Conclusion: In two prospective studies, greater adherence to a Mediterranean diet was associated with a significantly lower risk of later-onset CD

Lifestyle factors for the prevention of inflammatory bowel disease

Objective To estimate the proportion of cases of Crohn's disease (CD) and ulcerative colitis (UC) that could be prevented by modifiable lifestyle factors. Design In a prospective cohort study of US adults from the Nurses' Health Study (NHS; n=72 290), NHSII (n=93 909) and Health Professionals Follow-up Study (HPFS; n=41 871), we created modifiable risk scores (MRS; 0-6) for CD and UC based on established lifestyle risk factors, and healthy lifestyle scores (HLS; 0-9) derived from American healthy lifestyle recommendations. We calculated the population attributable risk by comparing the incidence of CD and UC between low-risk (CD-MRS≤1, UC-MRS≤2, HLS≥7) and high-risk groups. We externally validated our findings in three European cohorts: the Swedish Mammography Cohort (n=37 275), Cohort of Swedish Men (n=40 810) and European Prospective Investigation into Cancer and Nutrition (n=404 144). Results Over 5 117 021 person-years of follow-up (NHS, HPFS: 1986-2016; NHSII: 1991-2017), we documented 346 CD and 456 UC cases. Adherence to a low MRS could have prevented 42.9% (95% CI 12.2% to 66.1%) of CD and 44.4% (95% CI 9.0% to 69.8%) of UC cases. Similarly, adherence to a healthy lifestyle could have prevented 61.1% (95% CI 16.8% to 84.9%) of CD and 42.2% (95% CI 1.7% to 70.9%) of UC cases. In our validation cohorts, adherence to a low MRS and healthy lifestyle could have, respectively, prevented 43.9%-51.2% and 48.8%-60.4% of CD cases and 20.6%-27.8% and 46.8%-56.3% of UC cases. Conclusions Across six US and European cohorts, a substantial burden of inflammatory bowel diseases risk may be preventable through lifestyle modification

Skuldkvotens regionala skillnader - En ekonometrisk panelstudie för Sveriges kommunala skillnader i hushållens skuldkvot under perioden 2010-2015.

Since the mid-1990’s, citizens of Sweden have nearly doubled their income-debt ratio and international institutions such as IMF and OECD consider the indebtedness to be of considerable risk for Sweden’s economy. In 2013, Riksbanken started to gather credit-information from the largest operative banks in purpose of acquiring a better perception of household debt risk. Municipals of Sweden exhibit great regional differences, regarding income-debt ratio as well as population, housing prices and levels of education. This study aims to examine the regional differences in income-debt ratios between Sweden’s municipals. Furthermore, it aims to identify the causing factors of increasing household indebtedness. Based on earlier research, ten independent variables have been chosen. Secondary data is used from all of Sweden’s 290 municipals, over the period 2010 to 2015. Our method of choice resulted in a panel-data study which captures the specific municipal differences. Our result presented five variables with similar signs as predicted, based on earlier research. One variable presented the opposite effect, and for three variables no statistical significance was identified. According to previous research, the causality of the independent variables can be hard to determine. Recognizing causality is complex and arguments are presented for the plausibility of each direction. This study does not offer in-depth explanation of the causality for the variables but encouragement is given for further research in the subject. True effect could be of great importance to policymakers in efforts to halt a potential over-indebtedness in Swedish households

Aerodynamic performance in bat flight

Bats are the only mammals capable of flight, and they are the only animal flyers that are mammals. This thesis focuses on the latter of those facts, and investigates how bats fly, from an aerodynamic perspective. The data on which this thesis is based were generated by examining the airflows beneath and behind bats flying in a wind tunnel, and by examining their wing kinematics manually and automatically, using high-speed cameras. We analysed the data by writing computer scripts and interfaces that calculated forces, powers, efficiencies, and kinematical and morphological parameters. Among other things, we found hovering bats to have asymmetrical wingbeats with regard to up- and downstroke, discovered new levels of complexity in the wakes of large-eared bats, quantified the aerodynamic consequences of large ears in bat flight, and we devised a new method for automatically reconstructing the wing shapes of flying animals

Angular Distribution of Light in the Habitat of Cuttlefish

This work presents a way of analysing photographs stored in Canon’s CR2-format in order to analyse the light intensity profile of the area where the photographs were taken. A set of underwater photographs of the habitat of the Cuttlefish, Sepia officinalis, were provided for this thesis. The light intensity profile of the habitat of the cuttlefish is of interest because of the unusual shape of its pupils. Programs were developed for obtaining data from the provided photographs. The results show that the light conditions do vary greatly with angle