Interaction of a point charge with the surface of a uniaxial dielectric

We analyze the force on a point charge moving at relativistic speeds parallel to the surface of a uniaxial dielectric. Two cases are examined: a lossless dielectric with no dispersion and a dielectric with a plasma type response. The treatment focuses on the peculiarities of the strength and direction of the interaction force as compared to the isotropic case. We show that a plasma type dielectric can, under specific conditions, repel the point charge.Comment: 7 pages, 5 figure

Relationship between unilateral and bilateral countermovement jump performance and force-velocity-power outcome variables

The main objective of the present study was to check the relationship between commonly used unilateral and bilateral countermovement jump (CMJ) performance variables (jump heights, unilateral CMJ jump/bilateral CMJ jump height index, reactive strength index modified and bilateral deficit) and Force-velocity- Power (F-v-P) outcomes from loaded CMJs. Seventeen physical education students performed unilateral CMJ jumps, bilateral CMJ jumps and two-load (20 and 70% of the participant’s body mass) F-v-P tests. The results show that bilateral CMJ jump, unilateral CMJ jump height and the reactive strength index modified calculated from the bilateral CMJ jump are moderately correlated (r = 0.567-0.633, p<.05) to F0. No statistically significant correlations were found between F-v-P outcomes and unilateral CMJ jump height to bilateral CMJ jump index, reactive strength index modified calculated from the unilateral CMJ jump and bilateral deficit. Multiple linear stepwise regressions between F-v-P outcomes and performance variables revealed that only F0 can be statistically significantly predicted by CMJ height (R2 = 40 %). Although the unilateral and bilateral CMJ tests are less time-consuming and less fatiguing than the progressive loaded CMJ jump test, the results of our study show that the mechanical properties of the lower extremities obtained by unilateral CMJ jump and bilateral CMJ jump cannot be generalized to those measured by F-v-P profiling

USPOREĐIVANJE BIHEVIORISTIČKOG I KONSTRUKTIVISTIČKOG UČENJA I PODUČAVANJA

The difference between the behaviouristic and constructivist approach to learning and teaching originates from different notions of knowledge. Currently in Slovenia the behaviouristic approach dominates as it is present in the whole educational system and teachers are more familiar with it. Those teachers who have different notions of knowledge are introducing a changed approach to learning and teaching that follows from the constructivist paradigm. Both are facing dilemmas that concern teachers in practice more than they do initiators of changes who do not work directly in practice. The consequences of the introduction of changes include different notions of evaluation, examination and assessment. From a didactic point of view the role of feedback changes as it is transferred from assessment to examination. From a student’s perspective, it is not the role of feedback that is essential but its meaning.Razlika između biheviorističkog i konstruktivističkog pristupa učenju i podučavanju proizlazi iz različitog poimanja znanja. U Sloveniji trenutno prevladava bihevioristički pristup učenju i podučavanju, jer ga učitelji najbolje poznaju, a bio je prisutan i u cijelom obrazovnom sustavu. Oni učitelji koji drugačije vrednuju znanje, uvode promijenjen pristup učenju i podučavanju koji proizlazi iz konstruktivističke paradigme. Oba pristupa se suočavaju s nekoliko dilema koje su više prisutne među učiteljima u praksi, nego kod predlagatelja promjena koji ne rade neposredno u praksi. Posljedice uvođenja promjena uključuju različita tumačenja vrednovanja, provjeravanja i ocjenjivanja. S didaktičnog pogleda uloga povratne informacije se mijenja. Njeno težište se prenosi s ocjenjivanja na provjeravanje. Za učenika nije bitna uloga povratne informacije već njeno značenje

Analysis of tourism flows in the city based on tourists' online posts

Tourist web applications like TripAdvisor are collecting and displaying posts and comments from tourists on various locations. With today's technologies, we can easily scrap this information from the web. The goal or problem of the thesis is the identification and analysis of tourism flows based on the above mentioned posts, and comments of tourists in the area of the city size. As a solution to this problem, we created a web application prototype, which enables us to analyse tourism flows, to visualize them and to interpret them more easily. The tourism flow is a repeatable movement of tourists in the geographical area. For the analysis we collected and analysed the data for the cities of Ljubljana and Vienna. We analysed the individual city with the help of the prototype and in the end the results we obtained were presented in detail

Volume frequency analysis using HEC-SSP software

In recent decades we are increasingly facing with many hydrological problems that pose a great challenge and test for humanity. Today, there is a significant need for tools that perform complex analysis of the hydrological regime. On the possible extreme events can be partially prepared and we can effectively implement measures to protect only through adequate studying, predicting and forecasting them.\ud Knowing the interdependence of flow – duration – frequency allows more complex frequency analysis, which comprehensively defines the occurrence and impact of different interventions on the phenomena. Volume frequency analysis involves classic frequency analysis of maximum (minimum) flow within each of a set of specified durations. Average flow rates are first calculated based on different fixed durations. Then, for each duration frequency analysis of maximum (minimum) flow is performed with selected theoretical distribution.\ud In the thesis we performed volume frequency analysis with HEC – SSP software for gauging stations in Slovenia. The entire course of volume frequency analysis is shown for gauging station Jesenice on the river Sava Dolinka. The results were used for the case of the reservoir HPP Moste, where we tried to show how the containment of flood flows with different durations influence on reducing the flow downstream of the barrier. We also determined the necessary containment volume of the reservoir for a given maximum inflow volume and the operational installed flow of the HPP Moste

Erosive injury and prosthetic supply

Uvod: Obraba trdih zobnih tkiv je posledica več različnih dejavnikov, ki se med seboj prepletajo. Kisline, ki povzročajo zobno erozijo, delimo na zunanje (kisle pijače, kisla hrana) in notranje (bruhanje, gastroezofagealna refluksna bolezen). Z razvojem kompozitnih materialov in adhezivov je zobno erozijo mogoče oskrbeti konservativno. Še vedno pa je tudi uporaba keramičnih lusk, onlejev, prevlek in indirektnih dolgotrajnih provizorijev ustrezna oskrba pri zelo napredovali erozivni obrabi trdih zobnih tkiv. Namen: Namen diplomskega dela je predstaviti erozijske poškodbe zob, različne vrste erozijskih poškodb ter njihov vpliv na zobe in obzobna tkiva ter oskrbo zob s fiksno protetiko. S pregledom strokovne in znanstvene literature želimo raziskati pogostost teh bolezni in vzroke za nastanek, oblike in simptome bolezni ter posledice bolezni na zdravje zob. Metode: Uporabljena je bila deskriptivna metoda dela s kritičnim pregledom strokovne literature. Literaturo smo iskali po ključnih besedah v internetnih bazah podatkov z oddaljenim dostopom do informacijskih virov prek spletne strani Zdravstvene fakultete na PubMed, MEDLINE, Europe PubMed Central, BioMed Central in Google učenjak ter v internetnih bazah z oddaljenim dostopom Mestne knjižnice Kranj na EBSCO host. Literaturo smo iskali tudi v fizični obliki v knjižnici Zdravstvene fakultete Ljubljana in Mestni knjižnici Kranj s pregledom knjig izdanih po letu 1999. Razprava in zaključek: Ker je vedno bolje preprečiti kot zdraviti, bi moral biti v sodobnem zdravstvu večji poudarek na preventivi kot kurativi. Današnja zdravstvena obravnava bolnikov z erozivnimi poškodbami zob zahteva zelo specifičen pristop. Če zobozdravnik sumi, da je vzrok za nastanek zobne erozije bulimija nervoza, mora do pacienta pristopiti prijazno in brez obsojanja ter ga usmeriti v ustrezno obravnavo. Tak bolnik potrebuje multidisciplinarni pristop.Introduction: The wear of hard dental tissues is due to several different factors that intertwine. Acids that cause tooth erosion are divided into external (acidic beverages, acidic foods) and internal (vomiting, gastroesophageal reflux disease). With the development of composite materials and adhesives, dental erosion can be supplied conservatively. However, the use of ceramic scales, onlays, overdrafts, and indirect long-term provenances is still an appropriate supply in the highly advanced erosive wear of hard dental tissues. Purpose: The purpose of the diploma work is to present erosion damage to teeth, various types of erosion injuries and their influence on teeth and tumors and tooth care with fixed prosthetics. By reviewing professional and scientific literature, we want to explore the frequency of these diseases and the causes of the formation, the forms and symptoms of the disease, and the consequences of the disease on the health of teeth. Methods: A descriptive method of work was used with a critical review of professional literature. We searched literature for key words in Internet databases with remote access to information resources through the website of the Faculty of Medicine at PubMed, MEDLINE, Europe PubMed Central, BioMed Central and Google Scholar, and in the online databases with the remote access of the Kranj City Library at EBSCO host. We also searched for literature in a physical form in the library of the Ljubljana Faculty of Medicine and in the Kranj City Library with an overview of books published after 1999. Discussion and conclusion: Since it is always better to avoid being trained, modern health care should focus more on prevention than on curative. Today\u27s medical treatment of patients with erosive tooth damage requires a very specific approach. In the event that the dentist suspects that the cause of dental erosion is nervousness, the patient must approach the patient kindly and without condemnation and direct him to appropriate treatment. Such a patient needs a multidisciplinary approach

Influence of alignment on ear recognition

Ear as a biometric modality presents a viable source for automatic human recognition especially in surveillance scenarios where face is not seen frontally. In recent years local description methods have been gaining on popularity due to their invariance to illumination and occlusion. However, these methods require that images are well aligned and preprocessed as good as possible. This causes one of the greatest challenges of ear recognition: sensitivity to pose variations. In this paper we test the influence of alignment on recognition performance on images from recently presented Annotated Web Ears dataset with alignment methods Random sample consensus (RANSAC) and Cascaded Pose Regression (CPR). We prove that alignment improves recognition rate but only on images with small angle on roll and yaw axis. On other pictures RANSAC and CPR fails to align ears and recognition rate is therefore lower versus unaligned pictures. Those pictures should be addressed with more advanced alignment methods in order to improve recognition rate

Finding planar regions

Preiskovali smo problem iskanja ravnin na trianguliranem terenu. Za množico točk v prostoru zgradimo Delaunayjevo triangulacijo in z dvema različnima metodama poiščemo ravnino na terenu. V prvi metodi uporabimo algoritem za iskanje največjega konveksnega poligona. Algoritem se dobro obnese na manjši množici točk, na večji množici točk, pa zaradi svoje kvadratične časovne zahtevnosti ne pride v poštev. V drugi metodi uporabimo aproksimacijski algoritem. Ta se bolje obnese tudi na večji množici podatkov, kot tudi na realnih geografskih podatkih, ki jih lahko dobimo na spletnem portalu LIDAR. Implementiran vmesnik nam pomaga, da na enostaven način testiramo obe metodi in vizualiziramo rezultate.We studied the problem of finding planar regions in a triangulated terrain. For a set of points in 3-space, we construct the Delaunay triangulation. Then, with two different methods we look for a region which is flat. The first method uses an algorithm to find the largest convex polygon. The algorithm works well on smaller sets of points, but on larger sets of points it performs poorly due to its quadratic time complexity. In the second method, we use an approximation algorithm. It performs better on larger data sets, as well as on real geographical data, which can be obtained on the web portal LIDAR. The implemented interface helps us to test both methods in an easy way and visualize the results