Nuclear star cluster formation in energy-space

In a virialized stellar system, the mean-square velocity is a direct tracer of the energy per unit mass of the system. Here, we exploit this to estimate and compare root-mean-square velocities for a large sample of nuclear star clusters and their host (late- or early-type) galaxies. Traditional observables, such as the radial surface brightness and second-order velocity moment profiles, are subject to short-term variations due to individual episodes of matter infall and/or star formation. The total mass, energy and angular momentum, on the other hand, are approximately conserved. Thus, the total energy and angular momentum more directly probe the formation of galaxies and their nuclear star clusters, by offering access to more fundamental properties of the nuclear cluster-galaxy system than traditional observables. We find that there is a strong correlation, in fact a near equality, between the root-mean-square velocity of a nuclear star cluster and that of its host. Thus, the energy per unit mass of a nuclear star cluster is always comparable to that of its host galaxy. We interpret this as evidence that nuclear star clusters do not form independently of their host galaxies, but rather that their formation and subsequent evolution are coupled. We discuss how our results can potentially be used to offer a clear and observationally testable prediction to distinguish between the different nuclear star cluster formation scenarios, and/or quantify their relative contributions.Comment: 12 pages, 3 figures, 4 tables; accepted for publication in MNRA

Learning processes of students in competence based pre-vocational secondary education

The purpose of this study was to validate a causal and hierarchical model to elaborate on the relation between goal orientations, information processing strategies and development of conceptual knowledge of pre-vocational secondary education-students. This model can be used to describe students' learning processes in competence-based education. Preferences of students (n=719) for certain types of goals and information processing strategies were examined using questionnaires. The development of conceptual knowledge was investigated by having students create concept maps before and after a learning situation (e.g. project). Results of causal and hierarchical analyses showed that students' preferences for mastery and performance goals positively affected their preferences for using deep processing strategies. Performance of surface processing strategies had a negative effect on the development of conceptual knowledge

Сучасні тенденції розвитку міжнародних торговельно-економічних відносин

У статті визначено і обґрунтовано сучасні тенденції розвитку міжнародних торгівельно-економічних відносин. Проаналізовано основні макроекономічні показники США, Японії, країн-членів ЄС, країн, що розвиваються, їх зміну в процесі глобалізації і в період економічної кризи. Ключові слова: торгівля, економічні відносини, макроекономічні показники, США, Японія, ЄС, економічна криза.В статье определены и обоснованы современные тенденции развития международных торгово-экономических отношений. Проанализированы основные макроэкономические показатели США, Японии, стран-членов ЕС, развивающихся стран, их изменения в процес се глобализации и в период экономического кризиса. Ключевые слова: торговля, экономические отношения, макроэкономические показатели, США, Япония, ЕС, экономический кризис.The article specifies and substantiates current trends of developing international trade and economic relations. Basic macroeconomic indices of the USA, Japan, members EU, developed countries, their transformations in the process of globalization, as well as in the period of economic crisis are analyzed. Key word: trade, economic relations, macroeconomic indices, USA, Japan, EU, economic crisis

Oppervlakte en urine-afvoer van de dichte vloer in relatie tot hokbevuiling bij vleesvarkens

Hokbevuiling bij vleesvarkens vormt geen probleem bij een hoeveelheid dichte vloer tot maximaal 0,3 m2 per dier. Er moet dan wel aan een aantal voorwaarden worden voldaan

Грошово-кредитна система Сполучених Штатів Америки

У статті розглядаються проблеми функціонування грошово-кредитної системи Сполучених Штатів Америки — однієї з найбільш розвинених країн світу. Ключові слова: центральний банк, комерційні банки, небанківські кредитні установи, грошова одиниця, грошово-кредитна система.В статье рассматриваются проблемы функционирования денежно-кредитной системы Соединенных Штатов Америки, одной из наиболее развитых стран мира. Ключевые слова: центральный банк, коммерческие банки, небанковские кредитные учреждения, денежная единица, денежно-кредитная система.The problems of functioning of the money-andcredit United States of America are examined in the article, one of the most prosperous countries world. Key words: Central bank, commercial banken, nonbanken of credit institution, money unit, gold-credit system

Probing the AGN Unification Model at redshift z ∼\sim 3 with MUSE observations of giant Lyα\alpha nebulae

A prediction of the classic active galactic nuclei (AGN) unification model is the presence of ionisation cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly$\alpha$ nebulae around AGNs at redshift z$\sim$3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of 4 Ly$\alpha$ nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances $r>30$~physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionising geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r$\lesssim$30 pkpc) and the associated high values of the HeII to Ly$\alpha$ ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly$\alpha$ nebulae can be used to understand and study the geometry of high redshift AGNs on circum-nuclear scales and it lays the foundation for future studies using much larger statistical samples.Comment: 15 pages, 13 figures, accepted for publication in MNRA

Using Megamaser Disks to Probe Black Hole Accretion

We examine the alignment between H_2O megamaser disks on sub-pc scales with circumnuclear disks and bars on <500 pc scales observed with HST/WFC3. The HST imaging reveals young stars, indicating the presence of gas. The megamaser disks are not well aligned with the circumnuclear bars or disks as traced by stars in the HST images. We speculate on the implications of the observed misalignments for fueling supermassive black holes in gas-rich spiral galaxies. In contrast, we find a strong preference for the rotation axes of the megamaser disks to align with radio continuum jets observed on >50 pc scales, in those galaxies for which radio continuum detections are available. Sub-arcsecond observations of molecular gas with ALMA will enable a more complete understanding of the interplay between circumnuclear structures.Comment: Error in Figure 4 corrected, references added. 7 pages, 4 figures, to be published in the Astrophysical Journa