52 research outputs found

    Effect of Noise on the Standard Mapping

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    The effect of a small amount of noise on the standard mapping is considered. Whenever the standard mapping possesses accelerator modes (where the action increases approximately linearly with time), the diffusion coefficient contains a term proportional to the reciprocal of the variance of the noise term. At large values of the stochasticity parameter, the accelerator modes exhibit a universal behavior. As a result the dependence of the diffusion coefficient on the stochasticity parameter also shows some universal behavior.Comment: Plain TeX, 18 pages, 4 figure

    Imaging Cool Giant Planets in Reflected Light: Science Investigations and Synergy with Habitable Planets

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    Planned astronomical observatories of the 2020s will be capable of obtaining reflected light photometry and spectroscopy of cool extrasolar giant planets. Here we explain that such data are valuable both for understanding the origin and evolution of giant planets as a whole and for preparing for the interpretation of similar datasets from potentially habitable extrasolar terrestrial planets in the decades to follow.Comment: Science white paper submitted to the Astro 2020 Decadal Survey on Astronomy and Astrophysics. Replace version to fix typo in co-signer name and add figure credit

    Suppression of CD4+ T-Cells in the Spleen of Mice Infected with Toxoplasma gondii KI-1 Tachyzoites

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    Toxoplasma gondii KI-1, a recent new isolate from Korea, shows similar pathogenicity and infectivity to mice compared to the virulent RH strain. To understand characteristics of host immunity, including immune enhancement or suppression, we investigated proliferative responses and phenotypes of spleen cells. In addition, kinetics of IFN-γ, a Th1 cytokine, was examined in BALB/c mice up to day 6 post-infection (PI). Intraperitoneal injection of mice with 103 KI-1 tachyzoites induced significant decreases (P < 0.05) in proliferative responses of spleen cells. This occurred at days 2-6 PI even when concanavalin A (con A) was added and when stimulated with KI-1 antigen, suggesting suppression of the immunity. CD4+ T-cells decreased markedly at day 2 PI (P < 0.05), whereas CD8+ T-cells, NK cells, and macrophages did not show significant changes, except a slight, but significant, increase of CD8+ T-cells at day 6 PI. The capacity of splenocytes to produce IFN-γ by con A stimulation dropped significantly at days 2-6 PI. These results demonstrate that intraperitoneal injection of KI-1 tachyzoites can induce immunosuppression during the early stage of infection, as revealed by the decrease of CD4+ T-cells and IFN-γ

    A critique of teaching approach on the higher education level

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    Na visokoškolskim institucijama u Hrvatskoj nastavnom se radu nažalost ne pridaje značenje kakvo mu pripada. Ukorak s rehabilitacijom vrednovanja nastavnog rada na fakultetima treba razvijati svijest o potrebi sustavne izobrazbe nastavnika na fakultetima za rad u nastavi s ciljem podizanja kvalitete nastave. Danas smo suočeni i s izazovom permanentne motivacije studenata; od motivacije za upis, pa nadalje. Zadaća je fakulteta koncipirati i provoditi politiku usmjerenu ponajprije na studente, od potencijalnih studenata pa do upisanih, dakle i prije upisa, tijekom čitavog studija, ali i poslije, u okviru cjeloživotnog učenja. Aktualni i zanimljivi programi bez kvalitetnih nastavnika nisu dostatni. Uspješnijem studiranju ne pridonosi samo razvijenost strategija i vještina učenja studenata nego i način poučavanja nastavnika. Od čitavog spektra načina poučavanjai nastavnih metoda uglavnom se koriste frontalni rad i metoda usmenog izlaganja. Opisivanje je pretežito znanstveno, nedostatno se provjerava razumijevanje tijekom samoga nastavnog procesa, needucirani nastavnici nisu dorasli didaktičkom vođenju studenata... To su samo neke od slabosti koje bitno umanjuju kvalitetu visokoškolskog obrazovanja. Rješavanje mnogih problema s kojima se susreću nastavnici i njihovi studenti zahtijeva od nastavnika i znanja iz područja didaktike, psihologije i metodike. Stoga je prijeko potrebno u tom smjeru uvesti značajne promjene na razini visokoškolskog obrazovanja. U radu su korišteni i neki rezultati istraživanja provedenog nad studentima prve godine Kemijsko-tehnološkog fakulteta u Splitu s ciljem ispitivanja učinkovitosti strategija učenja.In higher educational institutions class activities unfortunately do not have the importance they deserve. Following the rehabilitation of higher education class evaluation, the level of consciousness about the necessity of college teachers’ systematic education should be increased in order to improve the quality of education. Today, we face the challenge of students’ permanent motivation; from enrollment onwards. The task of college is to draft and apply an agenda that is primarily student oriented, towards both potential and registered ones; which is to be realized before enrolment, during the entire study, and later in the context of lifelong learning. Current interesting programs, without competent teachers are not suffi cient. Not only that the development of certain strategies and students learning skills contributes to successful studying, but also the teaching methods are crucial. From a wide range of teaching and educational methods, frontal work and the method of speech presentation are mostly used. Description is predominantly scholarly, comprehension is rarely questioned during class, uneducated teachers are not competent enough to didactically direct students; and these are only a few weaknesses which signifi cantly reduce the quality of higher education institutions. Solving many problems that teachers and their students encounter demands teachers’ knowledge in didactics, psychology and methodic. Therefore it is highly necessary to introduce certain changes on the level of higher education. This work incorporates results from survey conducted on students of Faculty of Chemistry and Technology in Split due to exploring the learning strategy effectiveness

    Imaging Cool Giant Planets in Reflected Light: Science Investigations and Synergy with Habitable Planets

    Get PDF
    Planned astronomical observatories of the 2020s will be capable of obtaining reflected light photometry and spectroscopy of cool extrasolar giant planets. Here we explain that such data are valuable both for understanding the origin and evolution of giant planets as a whole and for preparing for the interpretation of similar datasets from potentially habitable extrasolar terrestrial planets in the decades to follow
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