Are Some Milky Way Globular Clusters Hosted by Undiscovered Galaxies?

The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass - halo mass relation, the one GC in this galaxy supports extending the relationship between the number of GCs hosted by a galaxy and the galaxy's total mass about two orders of magnitude in stellar mass below the previous limit. For this empirically determined specific frequency of between 0.06 and 0.39 globular clusters per 10$^9$ $M_\odot$ of total mass, the surviving Milky Way (MW) subhalos with masses smaller than $10^{10} M_\odot$ could host as many as 5 to 31 GCs, broadly consistent with the actual population of outer halo MW GCs, although matching the radial distribution in detail remains a challenge. Using a subhalo mass function from published high resolution numerical simulations and a Poissonian model for populating those halos with the aforementioned empirically constrained frequency, we find that about 90$\%$ of these GCs lie in lower-mass subhalos than that of Eri II. From what we know about the stellar mass-halo mass function, the subhalo mass function, and the mass-normalized GC specific frequency, we conclude that some of the MW's outer halo GCs are likely to be hosted by undetected subhalos with extremely modest stellar populations.Comment: 5 pages, 4 figures; ApJL in pres

Children's musical events and ecological education in the kindergarten

Predmet ovog rada jest ukazati na dobrobit i važnost dramske i glazbene umjetnosti s temom ekološkog odgoja u dječjim vrtićima te potaknuti odgojitelje na podizanje dječje eko svijesti kroz priredbe s ekološkom tematikom kao jednostavan, djeci zanimljiv, koristan i poučan način. Pretražujući literaturu možemo primjetiti kako je, na žalost, jako malo stručnih i znanstvenih radova o dječjim priredbama. Također, bilo bi dobro da dječjih igrokaza s ekološkom tematikom, kao i igrokaza općenito ima više. U radu je kratki pregled literature o ekologiji općenito, ekološkom odgoju u dječjim vrtićima te o dječjim priredbama, a u drugom dijelu rada prikaz vlastitog iskustva sudjelovanja u organizaciji (uvježbavanju i izradi kostima) i provedbi dječjeg igrokaza s ekološkom tematikom te prijedlozi još nekih varijacija izvedbi istih.The subject of this paper is to point to the benefits and importance of dramatic and musical art with the theme of ecological education in kindergartens and to encourage educators to raise eco-consciousness through ecological events as a simple, interesting, useful and educational way for children. Looking at the literature, we can notice how unfortunately there are very few professional and scientific papers on children's shows and performances. In addition, it would be good to have more of children's plays with ecological theme as well as game plays in general. The paper presents a brief overview of ecology literature in general, ecological education in kindergartens and children's shows, and the second part of the paper presents my own experience of participating in organization (training and making costumes) and implementation of children's play with ecological theme and suggestions of some variations

THE INFLUENCE OF COPPER SOURCE IN DIET OF GROWING-FATTENING PIGS ON QUALITY OF BELLY FAT

This article reports on an investigation which was carried out to determine the influence of different copper source in diet of growing- fattening pigs on iodine number and fatty acid composition of belly fat. The experimental pigs were fed the same basic ration supplemented with 250 ppm Cu as follows: Group I CUSO₄, Group II CuCO₃, Group III CuO, Group IV CuCl₂. From the results of the investigation the following conclusion could be drawn: 1) Different sources of copper in diet of growing- fattening pigs have not had significant effect on iodine number of belly fat and sum of the saturated and unsaturated fatty acids respectively (P>0.05). The content of the single fatty acids was not identical in samples of the belly fat. 2) In relation ,to the iodine number acid the sum of the saturated and the unsaturated fatty acids respectively of the backfat samples of the same pigs (Crnojević and collaborators, 1975) the belly fat samples have had very significantly different results (P<0.01)

Deep imaging of Eridanus II and its lone star cluster

We present deep imaging of the most distant dwarf discovered by the Dark Energy Survey, Eridanus II (Eri II). Our Magellan/Megacam stellar photometry reaches $\sim$$3$ mag deeper than previous work, and allows us to confirm the presence of a stellar cluster whose position is consistent with Eri II's center. This makes Eri II, at $M_V=-7.1$, the least luminous galaxy known to host a (possibly central) cluster. The cluster is partially resolved, and at $M_V=-3.5$ it accounts for $\sim$$4\%$ of Eri II's luminosity. We derive updated structural parameters for Eri II, which has a half-light radius of $\sim$$280$ pc and is elongated ($\epsilon$$\sim$$0.48$), at a measured distance of $D$$\sim$$370$ kpc. The color-magnitude diagram displays a blue, extended horizontal branch, as well as a less populated red horizontal branch. A central concentration of stars brighter than the old main sequence turnoff hints at a possible intermediate-age ($\sim$$3$ Gyr) population; alternatively, these sources could be blue straggler stars. A deep Green Bank Telescope observation of Eri II reveals no associated atomic gas.Comment: 7 pages, 4 figures; ApJL accepte

Dwarf galaxies beyond our doorstep: the Centaurus A group

The study of dwarf galaxies in groups is a powerful tool for investigating galaxy evolution, chemical enrichment and environmental effects on these objects. Here we present results obtained for dwarf galaxies in the Centaurus A complex, a dense nearby (~4 Mpc) group that contains two giant galaxies and about 30 dwarf companions of different morphologies and stellar contents. We use archival optical (HST/ACS) and near-infrared (VLT/ISAAC) data to derive physical properties and evolutionary histories from the resolved stellar populations of these dwarf galaxies. In particular, for early-type dwarfs we are able to construct metallicity distribution functions, find population gradients and quantify the intermediate-age star formation episodes. For late-type dwarfs, we compute recent (~1 Gyr) star formation histories and study their stellar distribution. We then compare these results with properties of the dwarfs in our Milky Way and in other groups. Our work will ultimately lead to a better understanding of the evolution of dwarf galaxies.Comment: 6 pages, 5 figures; to appear in the proceedings of the conference "A Universe of dwarf galaxies" (Lyon, June 14-18, 2010

Soil moisture sensors based on metamaterials

In this paper novel miniature metamaterial-based soil moisture sensors are presented. The sensors are based on resonant-type metamaterials and employ split-ring resonators (SRR), spiral resonators and fractal SRRs to achieve small dimensions, high sensitivity, and compatibility with standard planar fabrication technologies. All these features make the proposedsensors suitable for deployment in agriculture for precise mapping of soil humidity

A close look at the Centaurus A group of galaxies IV. Recent star formation histories of late-type dwarfs around CenA

We study a sample of 5 dwarf irregular galaxies in the CenA/M83 group, which are companions to the giant elliptical CenA. We aim at deriving their physical properties over their lifetime and compare them to those of dwarfs located in different environments. We use archival HST/ACS data and apply synthetic color-magnitude diagram fitting in order to reconstruct the past star formation activity of the target galaxies. The average star formation rate for the studied galaxies ranges from 10^{-3} up to \sim 7x10^{-2} M_odot/yr, and their mean metallicities correlate with their luminosities (from [Fe/H]\sim -1.4 up to \sim -1.0). The form of the star formation histories varies across the sample, with quiescent periods alternating with intermittent enhancements in the star formation (from a few up to several times the average lifetime value). The dwarfs in this sample formed ~35% to ~60% of their stellar content prior to ~5 Gyr ago. The resulting star formation histories for the CenA companions are similar to those found for comparable Local Group and M81 group dwarfs. We consider this sample of dwarfs together with 5 previously studied M83 dwarf irregular companions. We find no trend of the average star formation rate with tidal index or distance from the main galaxy of the group. However, dwarfs with higher baryonic masses do show higher average star formation rates, underlining the importance of intrinsic properties in governing the evolution of these galaxies. On the other hand, there is also a clear trend when looking at the recent (~0.5-1 Gyr) level of activity. Namely, dwarfs within a denser region of the group appear to have had their star formation quenched while dwarfs located in the group outskirts show a wide range of possible star formation rates, thus indicating that external processes play a fundamental role, complementary to mass, in shaping the star formation histories of dwarf galaxies.Comment: 16 pages, 10 figures; A&A accepte

Antlia B: A faint dwarf galaxy member of the NGC 3109 association

We report the discovery of Antlia B, a faint dwarf galaxy at a projected distance of $\sim$72 kpc from NGC 3109 ($M_{V}$$\sim$$-$15 mag), the primary galaxy of the NGC 3109 dwarf association at the edge of the Local Group. The tip of the red giant branch distance to Antlia B is $D$=1.29$\pm$0.10 Mpc, which is consistent with the distance to NGC 3109. A qualitative analysis indicates the new dwarf's stellar population has both an old, metal poor red giant branch ($\gtrsim$10 Gyr, [Fe/H]$\sim$$-$2), and a younger blue population with an age of $\sim$200-400 Myr, analogous to the original Antlia dwarf, another likely satellite of NGC 3109. Antlia B has \ion{H}{1} gas at a velocity of $v_{helio,HI}$=376 km s$^{-1}$, confirming the association with NGC 3109 ($v_{helio}$=403 km s$^{-1}$). The HI gas mass (M$_{HI}$=2.8$\pm$0.2$\times$10$^{5}$ M$_{\odot}$), stellar luminosity ($M_{V}$=$-$9.7$\pm$0.6 mag) and half light radius ($r_{h}$=273$\pm$29 pc) are all consistent with the properties of dwarf irregular and dwarf spheroidal galaxies in the Local Volume, and is most similar to the Leo P dwarf galaxy. The discovery of Antlia B is the initial result from a Dark Energy Camera survey for halo substructure and faint dwarf companions to NGC 3109 with the goal of comparing observed substructure with expectations from the $\Lambda$+Cold Dark Matter model in the sub-Milky Way regime.Comment: 7 pages, 3 figures. Submitted to ApJ

Measuring the world - project in classroom teaching

Cilj novih načina odgoja i obrazovanja nije sličan principima tradicionalne nastave, već se okreće pripremanju učenika za sadržaje iz stvarnoga života kroz različite praktične načine. Projektna nastava se uvelike razlikuje od tradicionalnoga oblika nastave. Definira se kao oblik aktivnog učenja u kojemu učenici prema predloženome projektu samostalno dolaze do novih spoznaja. Temelj projektne nastave je istraživanje problema koji je prethodno postavljen od strane učitelja. Projektna nastava je uistinu usmjerena na učenika jer se često učenici u njoj otkrivaju. Otkrivanje je vidljivo kroz potrebe učenika i njihove mogućnosti koje pokazuju tijekom provedbe projekta. Nastavnici u hrvatskim školama su svjesni koristi koje sa sobom nosi primjena projekta u nastavi, ali rijetko se odlučuju na ovaj oblik organizacije podučavanja jer se uz to vežu organizacijski problemi.The aim of the new ways of education is not similar to the principles of traditional teaching but is turning to preparing students for real life content through various practical ways. Project teaching is largely different from the traditional form of learning. It is defined as the form of active learning in which pupils, according to the proposed project, come up to new knowledge independently. The subject of project teaching was explored a problem that was previously set by the teacher. Project teaching is really focused on students because it is often the pupils in it that disclose it. The discovery is visible through the needs of the pupil and their potentialities during the implementation of the project. Teachers in Croatian schools are aware of the benefits that enable it to apply the project to teaching, but they rarely decide on this form of association organization because they are sputaneous organizational problems. Today, the application of project mathematical learning in Croatia in most cases is related to the application of mathematics, as well as free activities or work beyond the expected teaching time