Invisibility in billiards

The question of invisibility for bodies with mirror surface is studied in the framework of geometrical optics. We construct bodies that are invisible/have zero resistance in two mutually orthogonal directions, and prove that there do not exist bodies which are invisible/have zero resistance in all possible directions of incidence

Modeling tourists' personality in recommender systems: how does personality influence preferences for tourist attractions?

Personalization is increasingly being perceived as an important factor for the effectiveness of Recommender Systems (RS). This is especially true in the tourism domain, where travelling comprises emotionally charged experiences, and therefore, the more about the tourist is known, better recommendations can be made. The inclusion of psychological aspects to generate recommendations, such as personality, is a growing trend in RS and they are being studied to provide more personalized approaches. However, although many studies on the psychology of tourism exist, studies on the prediction of tourist preferences based on their personality are limited. Therefore, we undertook a large-scale study in order to determine how the Big Five personality dimensions influence tourists' preferences for tourist attractions, gathering data from an online questionnaire, sent to Portuguese individuals from the academic sector and their respective relatives/friends (n=508). Using Exploratory and Confirmatory Factor Analysis, we extracted 11 main categories of tourist attractions and analyzed which personality dimensions were predictors (or not) of preferences for those tourist attractions. As a result, we propose the first model that relates the five personality dimensions with preferences for tourist attractions, which intends to offer a base for researchers of RS for tourism to automatically model tourist preferences based on their personality.GrouPlanner Project under the European Regional Development Fund POCI-01-0145-FEDER29178 and by National Funds through the FCT – Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within the Projects UIDB/00319/2020 and UIDB/00760/202

Особенности мозговой активности при алкогольной зависимости в задаче на ингибиторный контроль

Objective. To study neurophysiological correlates of inhibitory control to determine the features of inhibitionprocesses in alcohol dependence.Materials and methods. 77 patients with alcohol dependence were examined (42 men and 35 women) (F10.2 according to ICD-10). Patients were examined using a test to assess inhibitory control – Go/No – go. According to the task performance, patients were divided into two groups: group 1 – without inhibitory control impairments, group 2 – with impaired inhibitory control. During execution of test, electroencephalogram recordings were made according to the 10–20 system. The values of spectral power and coherence of θ-, α- and β-rhythms were analyzed. Statistical processing was carried out using nonparametric Mann–Whitney U-test and Wilcoxon W-test.Results. In patients with impaired inhibitory control, there was a decrease in the spectral power of the α-rhythm in the frontal cortex (p = 0.003), whereas in patients without inhibitory control disorders – in the Central cortex (p = 0.036). Patients with impaired inhibitory control responded by increasing β-power to cognitive stimulus in the occipital (p = 0.014), left temporal (p = 0.009) and right temporal (p = 0.008) cortex, while patients without inhibitory control disorders showed an increase in β-power only in the occipital (p = 0.007) and left temporal (p = 0.002) cortex. According to coherence data, patients with impaired inhibitory control have greater involvement of brain structures during the “Go/No – go” test in all frequency ranges.Conclusions. Patients with and without impaired inhibitory control have regional differences in changes in brain bioelectric activity during the “Go/No – go” test.Цель. Изучить нейрофизиологические корреляты ингибиторного контроля для определения особенностей процессов торможения при алкогольной зависимости.Материалы и методы. Обследованы 77 пациентов (42 мужчины и 35 женщин) с  алкогольной зависимостью (F10.2 по МКБ-10). Пациенты обследованы с помощью теста  для оценки ингибиторного контроля – Go/No – go. По результатам этого теста пациенты были разделены на две группы: группа 1 – без нарушения ингибиторного контроля, группа 2 – с нарушением ингибиторного контроля. Во время выполнения теста проводилась запись электроэнцефалограммы по системе «10–20». Анализировались значения спектральной мощности и когерентности θ-, α- и β-ритмов.  Статистическая обработка проводилась с применением непараметрического U-критерия Манна – Уитни и W-критерия Вилкоксона.Результаты. У пациентов с нарушенным ингибиторным контролем происходило снижение спектральной мощности α-ритма во фронтальной коре головного мозга (р = 0,003), тогда как у пациентов без нарушений ингибиторного контроля – в центральной  коре (р = 0,036). Пациенты с нарушенным ингибиторным контролем реагировали повышением β-мощности на когнитивный стимул в затылочной (р = 0,014), левой височной (р = 0,009) и правой височной (р = 0,008) коре, при этом у пациентов без нарушений ингибиторного контроля наблюдалось повышение β-мощности только в  затылочной (р = 0,007) и левой височной (р = 0,002) коре. По данным когерентности, у пациентов с нарушением ингибиторного контроля наблюдается большая вовлеченность  мозговых структур во время выполнения теста Go/No – go во всех частотных диапазонах.Заключение. Пациенты с нарушением и без нарушения ингибиторного контроля имеют региональные различия в изменениях биоэлектрической активности головного мозга в процессе выполнения теста Go/No – go

A new design for a green calcium indicator with a smaller size and a reduced number of calcium-binding sites

Genetically encoded calcium indicators (GECIs) are mainly represented by two- or one-fluorophore-based sensors. One type of two-fluorophore-based sensor, carrying Opsanus troponin C (TnC) as the Ca2+-binding moiety, has two binding sites for calcium ions, providing a linear response to calcium ions. One-fluorophore-based sensors have four Ca2+-binding sites but are better suited for in vivo experiments. Herein, we describe a novel design for a one-fluorophore-based GECI with two Ca2+-binding sites. The engineered sensor, called NTnC, uses TnC as the Ca2+-binding moiety, inserted in the mNeonGreen fluorescent protein. Monomeric NTnC has higher brightness and pH-stability in vitro compared with the standard GECI GCaMP6s. In addition, NTnC shows an inverted fluorescence response to Ca2+. Using NTnC, we have visualized Ca2+ dynamics during spontaneous activity of neuronal cultures as confirmed by control NTnC and its mutant, in which the affinity to Ca2+ is eliminated. Using whole-cell patch clamp, we have demonstrated that NTnC dynamics in neurons are similar to those of GCaMP6s and allow robust detection of single action potentials. Finally, we have used NTnC to visualize Ca2+ neuronal activity in vivo in the V1 cortical area in awake and freely moving mice using two-photon microscopy or an nVista miniaturized microscope

Окислительная деструкция ибупрофена в присутствии Фентон-катализатора на основе наночастиц MgFe2O4

Catalytic properties of MgFe2O4 nanoparticles during oxidative destruction of non-steroidal anti-inflammatory drug ibuprofen were studied. The influence of the conditions of the catalytic process on the efficiency of ibuprofen decomposition was established. It was shown that at the catalyst content of 0.5 g/L, H2O2 concentration of 20.0 mmol/L and pH of 6.0 for 40 min, a decrease in the ibuprofen concentration from 10.0 mg/L to less than detected limit is achieved. It was found that in the process of catalytic destruction the degree of ibuprofen mineralization reached 100 %. The conducted research shows the prospects of practical application of the developed Fenton-like heterogeneous catalyst for wastewater treatment from pharmaceutically active compounds.Изучены каталитические свойства наночастиц MgFe2O4 в процессе окислительной деструкции нестероидного противовоспалительного препарата ибупрофена. Установлено влияние условий проведения каталитического процесса на эффективность разложения ибупрофена. Показано, что при содержании катализатора 0,5 г/л, концентрации H2O2 20,0 ммоль/л и рН 6,0 в течение 40 мин достигается снижение концентрации ибупрофена с 10,0 мг/л до концентрации ниже предела обнаружения. Выявлено, что в процессе каталитической деструкции степень минерализации ибупрофена достигает 100 %. Проведенные исследования свидетельствуют о перспективности практического применения разработанного Фентон-подобного гетерогенного катализатора для очистки сточных вод от фармацевтически активных соединений

Web Based Postgraduate Thesis/Dessertation System - A Prototype

With the advancement of information communication technology in Malaysia, education field should take advantage to upgrade their learning and management techniques. Students should be allowed to learn anytime, anywhere and at their own place. However administration and lecture should be able to manage their work more effective and flexible. The web-based system is effective way to learning and managing education works. This report outlines the development of a web-based postgraduate thesis/dissertation management system (WPTS), which aimed to assist thesis/dissertation administration, supervisor and students in the better integration during students doing the thesis/dissertation works. This prototype system base on case study with a group of MSC(IT), administration, lecturer and students who participate in thesis/dissertation management activities. This report also presenting the tests conducted with users, it also contributed some perspective regarding benefits that gain by administration, supervisor and students, and recommends future application of the approach

Eco-friendly Synthesis of Gold Nanoparticles Using Camellia sinensis Phytoextracts

Biosynthesis of metal nanoparticles using plant materials involves a fairly rapid reduction of metallic materials. The reduction potential of phytochemicals in a tea extract to reduce gold salt (NaAuCl4) to the highly homogenous gold nanoparticles is presented. Phytoextracts were derived from the mixture of Camellia sinensis var. sinensis and Camellia sinensis var. assamica (green tea) leaves. The appearance of the phytoextract's sloping absorption peak with Au salt at the wavelength range 530-550 nm corresponded to the absorption of gold nanoparticles. Obtained nanoparticles were purified from phytoextract excess by centrifugation. Then they were studied by Raman and FTIR spectroscopy and AFM. It was found that the size of produced gold nanoparticles was in the range from 3 nm to 10 n

Клиническое значение коморбидности аффективных расстройств и алкогольной зависимости

The aim was to study the clinical-psychopathological, clinical-follow-up, clinical-dynamic features of mood disorders (MD) and alcohol use disorder (AUD) with their comorbidity combinations.Materials and methods. The study included 88 people with AUD and MD: 33 women (37.5%) and 55 (62.5%) men. The first group was 31 patients (35,0%) with AUD without comorbid affective symptoms, the second was 29 patients (33.0%) with MD without alcohol dependence, and the third was 28 patients (32.0%) with comorbid AUD and MD. There were no statistically significant differences between the groups by age and sex composition, by the level of statistical significance of differences (p = 0.115 – by sex, ð = 0.248 – by age). The study used clinical, psychopathological, clinical and follow-up, clinical, dynamic and statistical methods. Statistical processing was performed using Pearson’s χ2, Mann – Whitney U-test for comparing independent samples and Spearman’s correlation analysis (r).Results. Patients of the second and third groups were diagnosed with dysthymia more rarely in statistically significant values by the level of statistical significance of differences (10.4% and 32.1% respectively, p = 0.023) and this testifies to MD taking chronic course in patients with AUD. The average duration of bout of heavy-drinking in the first group was longer than in the third group – 7 (4; 17) and 5,5 (3.5; 9.5) days accordingly (p = 0.043). Duration of the disease in the first and third groups was 10 (6; 18.5) and 14 (10; 19.75) years, respectively (p = 0.036). It confirms the negative impact of comorbidity on the clinicaldynamic features in the case of co-existing of AUD and MD.Conclusion. The coexistence of alcohol dependence and affective pathology enhances the suicidal risk of certain diseases. A tendency to the early appearance of symptoms of AUD and their rapid dynamics, a shorter duration of light intervals of MD and AUC, a relatively low tolerance to alcohol and pronounced depressogenic effect of alcohol in the case of comorbidity were found. Цель исследования – изучение клинико-психопатологических, клинико-катамнестических, клинико-динамических особенностей аффективных расстройств (АР) и алкогольной зависимости (АЗ) приих коморбидных сочетаниях.Материалы и методы. Обследованы 88 человек с АР и АЗ – 33 женщины (37,5%) и 55 (62,5%)мужчин. Первая группа – 31 пациент (35,0%) с АЗ без коморбидной аффективной симптоматики,вторая – 29 больных (33,0%) с расстройством настроения без зависимости от алкоголя, третья – 28пациентов (32,0%) с коморбидным течением АЗ и АР. Между группами по половозрастному составупо уровню статистической значимости различий не выявлено (p = 0,115 – по половому составу, р= 0,248 – по возрастному составу). В исследовании использовался клинико-психопатологический,клинико-катамнестический, клинико-динамический и статистические методы. Статистическую обработку проводили с использованием χ2 Пирсона, U-критерия Манна – Уитни для сравнения независимых выборок и корреляционного анализа Спирмена (r).Результаты. У пациентов второй и третьей групп по уровню статистической значимости различийреже диагностировалась дистимия (10,4 и 32,1% соответственно, p = 0,023), что свидетельствует охроническом варианте течения аффективной патологии в группе пациентов, страдающих АЗ. Средняя продолжительность псевдозапоев в первой группе пациентов была выше – 7 (4; 17) сут, чем втретьей группе – 5,5 (3,5; 9,5) (p = 0,043). Давность заболевания в первой и третьей группах составила 10 (6; 18,5) и 14 (10; 19,75) лет соответственно (p = 0,036), что подтверждает негативное влияниекоморбидности на клинико-динамические особенности при сочетании АЗ и АР.Заключение. Сосуществование АЗ и аффективной патологии усиливает суицидальный риск отдельных заболеваний; в случае коморбидного течения АЗ и аффективной патологии отмечена тенденцияк раннему появлению симптомов АЗ и быстрой их динамике, меньшая продолжительность светлыхпромежутков АР и АЗ, относительно низкая толерантность к спиртному, более выражен депрессогенный эффект этилового спирта

Клиническая характеристика и эффективность антидепрессивной терапии аффективных расстройств при коморбидности с алкогольной зависимостью

 Aim. To determine the nosological and clinical features of mood disorders (MD) with comorbid alcohol use disorder (AUD) and efficiency of antidepressant therapy.Materials and methods. We examined 88 patients with MD and comorbid AUD – 33 females (37.5%) and 55 males (62.5%). The first group included 31 patients with AUD without comorbid affective symptoms, the second group contained 29 patients with MD without AUD, the third group included 28 patients with AUD and MD. In the study, we applied clinical-psychopathologic, clinical-dynamic, and statistical methods with Pearson’s χ2 test, Mann – Whitney U-test (for comparison of independent samples), Kruskal – Wallis test (for more than two independent samples), and Wilcoxon test (for comparison of dependent samples). At the level of statistical  significance, no differences between the groups according to the gender – age composition were revealed (p = 0.115 – according to gender composition, р = 0.248 – according to age composition, Pearson’s χ2 test).Results. The patients with the diagnosis of AUD with comorbid MD showed worse dynamics of the reduction of depressive [from 24.0 (18.3; 33.0) to 9.0 (4.3; 12.0) points according to the Structured Interview Guide for the Hamilton Depression Rating Scale – Seasonal Affective Disorder (SIGH-SAD)  (р = 0.001, Wilcoxon test)] and anxiety [from 20.5 (12.5; 25.0) to 5.5 (3.3; 8.0) points according to the Hamilton Anxiety Rating Scale (HARS) (р = 0.001, Wilcoxon test)] symptoms against the background of the therapy with initially lower indices compared to the group with MD alone [from 27.0 (21.0; 36.0) to 6.0 (5.0; 11.0) points according to SIGH-SAD (р = 0.001, Wilcoxon test) (intergroup differences upon admission р = 0.046; upon  discharge р = 0.683, Mann – Whitney U-test) and from 21.0 (14.0; 29.0) to 5.0 (3; 10.5) points according to HARS (р = 0.001, Wilcoxon test) (intergroup differences upon admission р = 0.082; upon discharge р = 0.825, Mann –  Whitney U-test)]. The course of AUD is characterized by a larger extent of malignancy in the group with a comorbidity: decrease in pathological  alcohol craving from 31.5 (16.3; 43.5) points to 8 (2.3; 14.8) (р = 0.001, Wilcoxon test) in the group with a comorbidity and from 29.5 (21.8; 37.0) to 7 (3.0; 11.3) points with AUD alone (р = 0.001, Wilcoxon test) (intergroup  differences upon admission р = 0.058; upon discharge р = 0.04, Mann – Whitney U-test on the Obsessive Compulsive Drinking Scale (OCDS).Conclusion. Clinical-dynamic characteristics of MD with comorbid AUD  result in therapeutic difficulties associated with comparatively worse dynamics of reduction of the symptoms of both diseases.   Цель исследования – определение нозологической структуры, клинических особенностей аффективных расстройств (АР) при коморбидности с алкогольной  зависимостью (АЗ) и эффективности антидепрессивной  терапии.Материалы и методы. Обследованы 88 человек с АР и АЗ – 33 женщины (37,5%) и 55 (62,5%) мужчин. Первая группа – 31 пациент с АЗ без коморбидной аффективной  симптоматики, вторая – 29 больных с расстройством настроения без зависимости от алкоголя, третья – 28  пациентов с коморбидным течением АЗ и АР. В исследовании применялись клинико-психопатологический,  клинико-динамический и статистический методы с  использованием критериев χ2 Пирсона, Манна – Уитни (для  сравнения независимых выборок), Краскела – Уоллиса (для более двух независимых выборок), Вилкоксона (для  сравнения зависимых выборок). По уровню статистической значимости различий между группами по половозрастному составу не выявлено (p = 0,115 – по половому составу, р = 0,248 – по возрастному составу, критерий χ2).Результаты. Пациенты с коморбидным диагнозом АЗ и АР демонстрируют худшую динамику редукции депрессивной (с 24,0 (18,3; 33,0) до 9,0 (4,3; 12,0) баллов по шкале SIGH-SAD (р = 0,001, критерий Вилкоксона)) и тревожной (с 20,5 (12,5; 25,0) до 5,5 (3,3; 8,0) баллов по шкале HARS (р = 0,001, критерий Вилкоксона)) симптоматики на фоне лечения, при изначально более низких показателях, в сравнении с группой с «чистыми» АР (с 27,0 (21,0; 36,0) до 6,0 (5,0; 11,0) баллов по SIGH-SAD (р = 0,001, критерий Вилкоксона) (межгрупповые различия при поступлении р = 0,046; при  выписке р = 0,683, критерий Манна – Уитни) и с 21,0 (14,0; 29,0) до 5,0 (3; 10,5) баллов по HARS (р = 0,001, критерий  Вилкоксона) (межгрупповые различия при поступлении р =  0,082; при выписке р = 0,825, критерий Манна – Уитни)).  Течение АЗ отличается большей злокачественностью в группе с коморбидностью: снижение патологического влечения к алкоголю с 31,5 (16,3; 43,5) балла до 8 (2,3; 14,8) (р = 0,001, критерий Вилкоксона) в группе с коморбидностью и с 29,5 (21,8; 37,0) до 7 (3,0; 11,3) баллов  при «чистой» АЗ (р = 0,001, критерий Вилкоксона) (межгрупповые различия при поступлении р = 0,058; при  выписке р = 0,04, критерий Манна – Уитни по обсессивно-компульсивной шкале употребления алкоголя). Заключение. Клинико-динамические характеристики  коморбидного сочетания АР и АЗ ведут к терапевтическим  затруднениям, сопряженным со сравнительно худшей  динамикой редуцирования симптомов каждого из заболеваний.

Alleviating the new user problem in collaborative filtering by exploiting personality information

The final publication is available at Springer via http://dx.doi.org/10.1007/s11257-016-9172-zThe new user problem in recommender systems is still challenging, and there is not yet a unique solution that can be applied in any domain or situation. In this paper we analyze viable solutions to the new user problem in collaborative filtering (CF) that are based on the exploitation of user personality information: (a) personality-based CF, which directly improves the recommendation prediction model by incorporating user personality information, (b) personality-based active learning, which utilizes personality information for identifying additional useful preference data in the target recommendation domain to be elicited from the user, and (c) personality-based cross-domain recommendation, which exploits personality information to better use user preference data from auxiliary domains which can be used to compensate the lack of user preference data in the target domain. We benchmark the effectiveness of these methods on large datasets that span several domains, namely movies, music and books. Our results show that personality-aware methods achieve performance improvements that range from 6 to 94 % for users completely new to the system, while increasing the novelty of the recommended items by 3-40 % with respect to the non-personalized popularity baseline. We also discuss the limitations of our approach and the situations in which the proposed methods can be better applied, hence providing guidelines for researchers and practitioners in the field.This work was supported by the Spanish Ministry of Economy and Competitiveness (TIN2013-47090-C3). We thank Michal Kosinski and David Stillwell for their attention regarding the dataset