Position-dependent mass models and their nonlinear characterization

We consider the specific models of Zhu-Kroemer and BenDaniel-Duke in a sech$^{2}$-mass background and point out interesting correspondences with the stationary 1-soliton and 2-soliton solutions of the KdV equation in a supersymmetric framework.Comment: 8 Pages, Latex version, Two new references are added, To appear in J.Phys.A (Fast Track Communication

New approach to (quasi)-exactly solvable Schrodinger equations with a position-dependent effective mass

By using the point canonical transformation approach in a manner distinct from previous ones, we generate some new exactly solvable or quasi-exactly solvable potentials for the one-dimensional Schr\"odinger equation with a position-dependent effective mass. In the latter case, SUSYQM techniques provide us with some additional new potentials.Comment: 11 pages, no figur

N-fold Supersymmetry in Quantum Systems with Position-dependent Mass

We formulate the framework of N-fold supersymmetry in one-body quantum mechanical systems with position-dependent mass (PDM). We show that some of the significant properties in the constant-mass case such as the equivalence to weak quasi-solvability also hold in the PDM case. We develop a systematic algorithm for constructing an N-fold supersymmetric PDM system. We apply it to obtain type A N-fold supersymmetry in the case of PDM, which is characterized by the so-called type A monomial space. The complete classification and general form of effective potentials for type A N-fold supersymmetry in the PDM case are given.Comment: 18 pages, no figures; Refs. updated, typos correcte

Morfološka ispitivanja mozga kanadske lasice (Mustela vison)

The mink is a strict carnivore and a seasonal breeder, which may be used as an experimental model for other carnivores. Using anatomical methods, 32 brains of the N. American mink were examined. It was found that the brain consists of four ventricles. Also, it was noted that the posterior horn was missing and that the olfactory recess was present in the lateral ventricle, a large-size interthalamic connection was present in the third ventricle, and a flat, necklace like bottom in the fourth ventricle. Only recently, the ins and outs of the mink’s anatomical structure have begun to absorb the attention of anatomists. Apparently, it is related to the fact that fury animals, among them the mink, are being domesticated. For this reason and because of easy access to the material, the purpose of brain dissection is to familiarize with the three dimensional structure of the brain and teach one of the great methods of studying the brain: looking at its structure.Kanadska lasica je karnivor, koji jednom godišnje daje 4-5 mladunaca, koji se koriste kao eksperimentalni model. Za anatomska ispitivanja, koristili smo 32 mozga oba pola kanadske lasice. Utvrdili smo da se u mozgu nalaze 4 komore, kao i kod ostalih sisara. Ustanovili smo da posteriorni rog bočne komore nedostaje, kao i da postoji olfaktorni izdanak bočne komore. Šira površina između talamusa je takodje ustanovljena u trećoj moždanoj komori, kao i udubljenje četvrte moždane komore. U poslednje vreme kao eksperimentalna životinja, kanadska lasica postaje predmet interesovanja anatoma kao i naučnih istraživača u velikom broju laboratorija. Takođe, divlje životinje postaju sve više domestifikovane, a među njima je i kanadska lasica

Rheological properties of hydroxypropylmethyl cellulose/sodium dodecylsulfate mixtures

Rheological properties of mixtures of hydroxypropylmethyl cellulose (HPMC), a nonionic associative cellulose ether, and sodium dodecylsulfate (SDS), an anionic surfactant, were investigated by viscosity measurements performed at different shear rates (0.1-6000 s-1). HPMC/SDS mixtures containing different concentrations of SDS (CSDS=0.00-3.50 % w/w) and HPMC concentrations which corresponded to the overlap parameter c/c*=3, 6, and 12 were prepared. All HPMC/SDS mixtures were found to be shear-thinning when examined in a low-end-to mid-range of the applied shear rates. The degree of shear-thinning, n, and viscosity of the mixtures were influenced by composition of HPMC/SDS mixtures and HPMC-SDS complex formation. The changes in n ranged from values typical for highly shear thinning to almost perfectly Newtonian liquids, and were more pronounced as c/c* was increased from 3 to 6 and 12. A change in flow profile and a buildup of the first normal stress difference (N1) was observed in HPMC/SDS mixtures with c/c*=6 and 12 and CSDS 0.55-1.00 % and 0.55-2.50 %, respectively, when a critical shear rate, crit. was exceeded, suggesting that a shear-induced structure formation in the mixtures took place. [Projekat Ministartsva nauke Republike Srbije, br. Grant III 46010

Spectrum generating algebras for position-dependent mass oscillator Schrodinger equations

The interest of quadratic algebras for position-dependent mass Schr\"odinger equations is highlighted by constructing spectrum generating algebras for a class of d-dimensional radial harmonic oscillators with $d \ge 2$ and a specific mass choice depending on some positive parameter $\alpha$. Via some minor changes, the one-dimensional oscillator on the line with the same kind of mass is included in this class. The existence of a single unitary irreducible representation belonging to the positive-discrete series type for $d \ge 2$ and of two of them for d=1 is proved. The transition to the constant-mass limit $\alpha \to 0$ is studied and deformed su(1,1) generators are constructed. These operators are finally used to generate all the bound-state wavefunctions by an algebraic procedure.Comment: 21 pages, no figure, 2 misprints corrected; published versio

A mechanism for the non-Fermi-liquid behavior in CeCu_{6-x}Au_x

We propose an explanation for the recently observed non-Fermi-liquid behavior of metallic alloys CeCu_{6-x}Au_x: near x=0.1, the specific heat c is proportional to T \ln (T_0/T) and the resistivity increases linearly with temperature T over a wide range of T. These features follow from a model in which three-dimensional conduction electrons are coupled to two-dimensional critical ferromagnetic fluctuations near the quantum critical point, x_{c}=0.1. This picture is motivated by the neutron scattering data in the ordered phase (x=0.2) and is consistent with the observed phase diagram.Comment: 4 pages, LaTeX, 3 figure

The influence of selenium and deiodinases blockers on juvenile rats body weight

In this work there was investigated the influence of selenium and deodinases blockers on juvenile rats body weight during three months. The experiment was carried out on 64 rats divided into eight groups with eight individual animals per group. Following groups were formed: 1. Se+PTU-IA- (control group), 2. Se+PTU+IA+, 3. Se+PTU+IA-, 4. Se+PTU- IA+, 5. Se-PTU-IA-, 6. Se-PTU+IA+, 7. Se-PTU+IA- and 8. Se-PTU-IA+. The groups labeled (Se+) were selenium adequate and they were fed with food that contained 0.334 mg Se/kg. The groups labeled (Se-) were selenium deficient and obtained food with 0.031 mg Se/kg. As deiodinases blockers there were used propylthiouracil (PTU+) in a dose of 150 mg/L of drinking water and iopanoic acid (IA+) in a dose of 6 mg/100 g TM intraperitoneally. Body weight of experimental rats was measured every seven days. After three weeks of treatment there were taken blood samples of animals from all experimental groups and following parameters were determined: selenium concentration in blood, thyroxine (T4), triiodothyronine (T3) and thyroidstimulating hormone (TSH) in blood plasma. Analysis of the samples showed that the animals from the groups treated with PTU had lower body weight in regard to the control group, as well as lower concentration of T3 and T4 in plasma. Selenium deficient rats had lower average body weight compared to the selenium adequate ones after three weeks, but there were no differences in thyroid hormones concentration. The lowest average body weight was noticed in selenium deficient rats groups treated with PTU. [Projekat Ministartsva nauke Republike Srbije, br. TR31050 i br. TR31003

Shape-invariant quantum Hamiltonian with position-dependent effective mass through second order supersymmetry

Second order supersymmetric approach is taken to the system describing motion of a quantum particle in a potential endowed with position-dependent effective mass. It is shown that the intertwining relations between second order partner Hamiltonians may be exploited to obtain a simple shape-invariant condition. Indeed a novel relation between potential and mass functions is derived, which leads to a class of exactly solvable model. As an illustration of our procedure, two examples are given for which one obtains whole spectra algebraically. Both shape-invariant potentials exhibit harmonic-oscillator-like or singular-oscillator-like spectra depending on the values of the shape-invariant parameter.Comment: 16 pages, 5 figs; Present e-mail of AG: [email protected]

Вплив трьох спортивних ігор з фізичного виховання на фізичну підготовленість студентів чоловічої статі

Background and Study Aim. Few controlled studies have been conducted on the effect of sports games as a physical education (PE) course on the health-related fitness of university students. The aim of the study was to determine whether three sports in a PE course will help improve the health-related fitness of male university students. Material and Methods. Students from two universities participated in the study, with one university acting as a control group. There were two PE courses which students registered for: a football and volleyball (FVG, n=169) course and a badminton (BG, n=97) course. The students received basic training drills and competed with one another. The duration of the activities was 50 minutes sessions for eight weeks. The following tests were taken before and after eight weeks: Cooper test, sit-and-reach test, 60-s curl test, standing long jump test, and body mass index. Paired t-tests were used to compare the baseline and post data of each group. The Welch t-test, ANCOVA, and analysis of gains scores were used to compare each of the PE groups to the control group. ANCOVA was used to account for baseline differences, while analysis of gains scores was used whenever ANCOVA could not be used. The Vargha-Delaney Effect Size (VD) and the Common Language Effect Size (CLES) were used to determine the effect sizes for the Welch t-tests and ANCOVA, respectively. Significant changes were set at p ≤ 0.05 and VD ≤ 42% or VD ≥ 58%, or if p ≤ 0.05 and CLES ≥ 58 %. Results.  Both PE groups showed significant improvements in all the measured fitness parameters except body composition. Moreover, the measured parameters of the control group reduced after eight weeks. Conclusion. The study shows evidence that PE courses can serve male universities in improving their health-related fitness. Moreover, students who do not participate in a PE course may be at risk of losing their fitness.Предпосылки и цель исследования. Было проведено мало контролируемых исследований о влиянии спортивных игр в качестве курса по физическому воспитанию (PE) на состояние здоровья студентов университетов. Цель исследования состояла в том, чтобы определить, помогут ли три вида спорта на курсе физического воспитания улучшить состояние здоровья студентов мужского пола.Материал и методы. В исследовании приняли участие студенты из двух университетов, один из которых выступал в качестве контрольной группы. Были два курса физическоого воспитания, на которые зарегистрировались студенты: курс по футболу и волейболу (FVG, n = 169) и курс по бадминтону (BG, n = 97). Студенты проходили базовые тренировки и соревновались друг с другом. Продолжительность занятий составляла 50 минут сеансов по восемь недель. Следующие тесты были взяты до и после восьми недель: тест Купера, тест гибкости, 60-секундный тест сгибания, тест прыжка в длину с места и индекс массы тела. Парные t-тесты использовались для сравнения базовых и пост-данных каждой группы. Для сравнения каждой из групп PE с контрольной группой использовались t-критерий Уэлча, ANCOVA и анализ результатов. ANCOVA использовалась для учета базовых различий, в то время как анализ показателей выигрышей использовался всякий раз, когда ANCOVA нельзя было использовать. Размер эффекта Варга-Делани (VD) и Размер эффекта общего языка (CLES) использовались для определения размеров эффекта для t-тестов Уэлча и ANCOVA, соответственно. Значительные изменения были установлены при p ≤ 0,05 и VD ≤ 42% или VD ≥ 58%, или если p ≤ 0,05 и CLES ≥ 58%.Результаты. Обе группы PE показали значительное улучшение всех измеренных параметров физической формы, кроме состава тела. Более того, измеренные параметры контрольной группы снизились через восемь недель.Выводы. Исследование показывает, что курсы PE могут помочь студентам улучшить свою физическую форму. Кроме того, студенты, которые не участвуют в курсе PE, могут подвергаться риску потерять свою физическую форму.Передумови та мета дослідження. Було проведено мало контрольованих досліджень про вплив спортивних ігор в якості курсу з фізичного виховання (PE) на стан здоров'я студентів університетів. Мета дослідження полягала в тому, щоб визначити, чи допоможуть три види спорту на курсі фізічного виховання поліпшити стан здоров'я студентів чоловічої статі.Матеріал і методи. У дослідженні взяли участь студенти з двох університетів, один з яких виступав в якості контрольної групи. Були два курси фізічного виховання, на які зареєструвалися студенти: курс по футболу і волейболу (FVG, n = 169) і курс з бадмінтону (BG, n = 97). Студенти проходили базові тренування і змагалися один з одним. Тривалість занять складала 50 хвилин сеансів по вісім тижнів. Наступні тести були взяті до і після восьми тижнів: тест Купера, тест гнучкості, 60-секундний тест згинання, тест стрибка в довжину з місця та індекс маси тіла. Парні t-тести використовувалися для порівняння базових і пост-даних кожної групи. Для порівняння кожної з груп PE з контрольною групою використовувалися t-критерій Уелча, ANCOVA і аналіз результатів. ANCOVA використовувалася для обліку базових відмінностей, в той час як аналіз показників виграшів використовувався щоразу, коли ANCOVA не можна було використовувати. Розмір ефекту Варга-Делані (VD) і розмір ефекту спільної мови (CLES) використовувалися для визначення розмірів ефекту для t-тестів Уелча і ANCOVA, відповідно. Значні зміни були встановлені при p ≤ 0,05 і VD ≤ 42% або VD ≥ 58%, або якщо p ≤ 0,05 і CLES ≥ 58%.Результати. Обидві групи PE показали значне поліпшення всіх виміряних параметрів фізичної форми, крім складу тіла. Більш того, виміряні параметри контрольної групи знизилися через вісім тижнів.Висновки. Дослідження показує, що курси PE можуть допомогти студентам покращити свою фізичну форму. Крім того, студенти, які не беруть участі в курсі PE, можуть піддаватися ризику втратити свою фізичну форму