Fast Simulation of Vehicles with Non-deformable Tracks

This paper presents a novel technique that allows for both computationally fast and sufficiently plausible simulation of vehicles with non-deformable tracks. The method is based on an effect we have called Contact Surface Motion. A comparison with several other methods for simulation of tracked vehicle dynamics is presented with the aim to evaluate methods that are available off-the-shelf or with minimum effort in general-purpose robotics simulators. The proposed method is implemented as a plugin for the open-source physics-based simulator Gazebo using the Open Dynamics Engine.Comment: Submitted to IROS 201

Interaural time difference processing in the mammalian medial superior olive

The dominant cue for localization of low-frequency sounds are microsecond differences in the time-of-arrival of sounds at the two ears [interaural time difference (ITD)]. In mammals, ITD sensitivity is established in the medial superior olive (MSO) by coincidence detection of excitatory inputs from both ears. Hence the relative delay of the binaural inputs is crucial for adjusting ITD sensitivity in MSO cells. How these delays are constructed is, however, still unknown. Specifically, the question of whether inhibitory inputs are involved in timing the net excitation in MSO cells, and if so how, is controversial. These inhibitory inputs derive from the nuclei of the trapezoid body, which have physiological and structural specializations for high-fidelity temporal transmission, raising the possibility that well timed inhibition is involved in tuning ITD sensitivity. Here, we present physiological and pharmacological data from in vivo extracellular MSO recordings in anesthetized gerbils. Reversible blockade of synaptic inhibition by iontophoretic application of the glycine antagonist strychnine increased firing rates and significantly shifted ITD sensitivity of MSO neurons. This indicates that glycinergic inhibition plays a major role in tuning the delays of binaural excitation. We also tonically applied glycine, which lowered firing rates but also shifted ITD sensitivity in a way analogous to strychnine. Hence tonic glycine application experimentally decoupled the effect of inhibition from the timing of its inputs. We conclude that, for proper ITD processing, not only is inhibition necessary, but it must also be precisely timed

Clemens Götze: Geschichte, Politik und Medien im dramatischen Spätwerk Thomas Bernhards, Edith Kovács: Richter und Zeuge

Rezension zu Clemens Götze: Geschichte, Politik und Medien im dramatischen Spätwerk Thomas Bernhards. Marburg: Tectum, 2009 Edith Kovács: Richter und Zeuge. Figuren des Autors in Thomas Bernhards Prosa. Wien: Praesens, 200

Modeling of population dynamics

Cílem této práce je popsat základní modely dynamiky populací. V první části jsou uvedeny modely dynamiky jedné populace, v druhé modely zabývající se koexistencí dvou biologických druhů. Vždy začínáme s popisem modelů jednodušších a postupně jsou vytvářeny modely realističtější. V poslední části jsou naznačeny další možnosti zpřesnění modelů, kterými se naše úvahy při modelování dynamiky populací mohou dále ubírat.The aim of this thesis is to describe the basic models of the population dynamics. In the first part of the thesis, the models which describe the dynamic of one population are mentioned, in the second part there are models of the coexistence of two biological kinds. We always begin with the description of the basic models and we try gradually to create models that are more realistic. In the last section further possibilities of pecification for the models, which can also be taken into account, are indicated.

STUDENTS WITH MENTAL HEALTH ISSUES IN HIGHER EDUCATION: A SURVEY OF PREVALENCE AND FALL-TO-SPRING PERSISTENCE RATES IN A COMMUNITY COLLEGE ENVIRONMENT

Among the multitude of challenges and adversities students face during their first year of higher education, many experience deterioration of their emotional or mental health. Current research focuses on the perceived rise in the breadth and complexity of student mental health concerns at four-year colleges and universities. Even though community college students encompass the majority of individuals enrolled in the United States higher education system, no research specifically examines the mental health prevalence of these students and whether these difficulties negatively impact persistence. This study explored the relationship between evidence of mental health problems and fall-to-spring persistence for first-year students at a small size Midwestern community college. Quantitative data were collected from a voluntary survey administered to students enrolled in the Fall term freshman orientation courses. The survey identified psychological symptoms and distress as measured by eight distinct Counseling Center Assessment of Psychological Symptoms (CCAPS-62) subscales, prior mental health treatment, gender, age, financial aid status, and employment status as possible predictor variables of student persistence. Persistence was evaluated by successful completion of the fall semester and enrollment in spring semester classes. Descriptive statistics, bivariate correlation data, and logistic regression analysis were used in this study. The findings provided evidence of the presence of mental health concerns among first-year community college students. Social anxiety and academic distress were the most commonly reported difficulties. Counseling services and the use of psychotropic medication were the most frequently sought after types of mental health treatment. Students who reported higher levels of academic distress also reported more depression and generalized anxiety symptoms. However, the logistic regression analyses failed to confirm that students’ mental health concerns or treatment were predictive of fall semester completion or spring semester reenrollment status

The natural history of sound localization in mammals story of neuronal inhibition

Our concepts of sound localization in the vertebrate brain are widely based on the general assumption that both the ability to detect air-borne sounds and the neuronal processing are homologous in archosaurs (present day crocodiles and birds) and mammals. Yet studies repeatedly report conflicting results on the neuronal circuits and mechanisms, in particular the role of inhibition, as well as the coding strategies between avian and mammalian model systems. Here we argue that mammalian and avian phylogeny of spatial hearing is characterized by a convergent evolution of hearing air-borne sounds rather than by homology. In particular, the different evolutionary origins of tympanic ears and the different availability of binaural cues in early mammals and archosaurs imposed distinct constraints on the respective binaural processing mechanisms. The role of synaptic inhibition in generating binaural spatial sensitivity in mammals is highlighted, as it reveals a unifying principle of mammalian circuit design for encoding sound position. Together, we combine evolutionary, anatomical and physiological arguments for making a clear distinction between mammalian processing mechanisms and coding strategies and those of archosaurs. We emphasize that a consideration of the convergent nature of neuronal mechanisms will significantly increase the explanatory power of studies of spatial processing in both mammals and birds

Abandoned brickyards and significant loess sections on the Brno-North map sheet

In total 22 abandoned brickyards on the territory of the 24-324 Brno-sever (Brno-North) map sheet were revisited and accessibility of their loess sections for sedimentological, paleontological and geohazard studies was checked. Brickyards along the Úvoz Street, between Lidická and Veveří streets, in Královo Pole and Černá Pole neighbourhoods are overbuilt with residential houses and inaccessible any more. Only the Růženin dvůr brickyard at Židenice has loess section available for a research. Better preserved loess sections were encountered in Brno vicinity, like the Jinačovice ravine, Bílovice brickyard, and ravine at Kníničky.In total 22 abandoned brickyards on the territory of the 24-324 Brno-sever (Brno-North) map sheet were revisited and accessibility of their loess sections for sedimentological, paleontological and geohazard studies was checked. Brickyards along the Úvoz Street, between Lidická and Veveří streets, in Královo Pole and Černá Pole neighbourhoods are overbuilt with residential houses and inaccessible any more. Only the Růženin dvůr brickyard at Židenice has loess section available for a research. Better preserved loess sections were encountered in Brno vicinity, like the Jinačovice ravine, Bílovice brickyard, and ravine at Kníničky

Evaluation of passive cooling system in plywood enclosure for agricultural robot prototype

Received: February 1st, 2021 ; Accepted: March 27th, 2021 ; Published: April 29th, 2021 ; Correspondence: [email protected] use of autonomous robots in agriculture has been increasing rapidly in recent years, but is hampered by the complexity of data recording and processing. The prototyping process involves many changes to the housing design during development. Using laser cutting to make a housing is more convenient, faster and cheaper than milling or casting if only one body needs to be made. To speed up the production of autonomous robot prototypes, the body was made of birch plywood using laser-cut parts. The study analyses the efficiency of passive cooling to make sure that birch wood plywood is suitable for the production of a robotic body for outdoor use in agriculture. Under laboratory conditions, temperature measurements were made inside and outside the housing to determine how the heat released by the electronic components dissipates into the environment. An exponential model with a static coefficient and a time constant can be used to determine the recommended operating time at different ambient temperatures when the allowable operating temperature of the component is known. Air flow and heat transfer simulations were performed to represent heat dissipation. Birch plywood can be used for the production of prototype enclosures for agricultural robots, but the design must provide technological solutions for heat dissipation to prevent overheating of electronic components