Are the nearby groups of galaxies gravitationally bound objects?

We have compared numerical simulations to observations for the nearby (< 40 Mpc) groups of galaxies (Huchra & Geller 1982 and Ramella et al. 2002). The group identification is carried out using a group-finding algorithm developed by Huchra and Geller (1982). Using cosmological N-body simulation code with the LambdaCDM cosmology, we show that the dynamical properties of groups of galaxies identified from the simulation data are, in general, in a moderate, within 2sigma, agreement with the observational catalogues of groups of galaxies. As simulations offer more dynamical information than observations, we used the N-body simulation data to calculate whether the nearby groups of galaxies are gravitationally bound objects by using their virial ratio. We show that in a LambdaCDM cosmology about 20 per cent of nearby groups of galaxies, identified by the same algorithm as in the case of observations, are not bound, but merely groups in a visual sense. This is quite significant, specifically because estimations of group masses in observations are often based on an assumption that groups of galaxies found by the friends-of-friends algorithm are gravitationally bound objects. Simulations with different resolutions show the same results. We also show how the fraction of gravitationally unbound groups varies when the apparent magnitude limit of the sample and the value of the cosmological constant is changed. In general, a larger value of the Omega_Lambda generates slightly more unbound groups.Comment: 13 figures and 7 tables, Accepted 2007 September 19. Received 2007 September 19; in original form 2007 April

Addressing climate vulnerability : promoting the participatory rights of indigenous peoples and women through Finnish foreign policy

Julkaistu versi

Aktivoiko ryhmävalmennus koulupudokkaita? -Potkua Päivään -ryhmävalmennus

Opinnäytetyön tavoitteena oli tutkia aktivoiko ryhmävalmennus koulupudokkaita. Kvalitatiivisessa tutkimuksessa teemahaastateltiin neljää 18–20 -vuotiasta nuorta, jotka osallistuivat yhdeksän viikon ajan Potkua Päivään -osahankkeen ryhmävalmennukseen. Tampereen Silta-Valmennusyhdistyksellä toteutettu Potkua Päivään -ryhmävalmennus oli valtakunnallisen Startti parempaan elämään -hankkeen osahanke. Ryhmävalmennuksen tavoitteena oli saada nuori aktivoitumaan oman elämänsä suunnitteluun ja miettimään opiskeluvaihtoehtoja. Ryhmävalmennuksen aloitti viisi nuorta, joilla kaikilla oli keskeytyneet ammatilliset opinnot ja siten olivat vailla ammatillista tutkintoa. Ryhmävalmennuksen lopetti yksi nuori, josta kerättyä aineistoa emme huomioi opinnäytetyössämme. Aineistona olivat alkukyselykaavakkeet, havaintoaineisto, teema- ja puhelinhaastattelut. Aineistojen avulla tutkittiin miten nuoret saavuttivat ryhmävalmennuksen alussa asettamansa tavoitteet, miten he sitoutuivat ryhmätoimintaan ja toteutuivatko syksylle 2010 tekemänsä suunnitelmat. Opinnäyte-työssä tuodaan esiin millaista toimintaa on tällä hetkellä koulutuksen ulkopuolella, vailla ammattitutkintoa, oleville nuorille. Tulokset osoittivat nuorten aktivoituneen oman elämänsä suunnitteluun. Kaikki neljä nuorta saavuttivat tavoitteensa: saivat selville haluamansa opiskelualan ja tekivät kevään 2010 yhteishaun. Toinen nuorten asettama tavoite, päivärytmin palauttaminen ei toteutunut. Tulosten mukaan sitoutuminen ryhmävalmennukseen osoittautui heikoksi. Syksyllä 2010 kaksi neljästä nuoresta aloitti opiskelut haluamassaan koulutuksessa. Kaksi nuorista ei saanut opiskelupaikkaa, heistä toinen aloitti toisen ryhmävalmennuksen ja toinen suunnitteli jatkavansa keskeytynyttä koulutustaan. Tulosten perusteella oli pääteltävissä erilaisten toimintojen auttavan koulupudokkaita aktivoitumaan oman elämänsä suunnitteluun.The purpose of this thesis was to examine whether group coaching activates school drop-outs. In a qualitative study four 18–20-year-old young adults were interviewed. These young adults participated in group coaching arranged by the Potkua Päivään (A Kick-Start for the Day) subproject for nine weeks. The Potkua Päivään group coaching implemented at Tampere Silta-Valmennusyhdistys (Tampere Bridge-Coaching Association) was a subproject of the national Startti Parempaan Elämään (A Start for a Better Life) project. The essential objective of the group coaching project was to activate the young people into planning their own lives and into considering study options. The group coaching project was entered by five young adults who had dropped out of their studies and were thereby without any vocational degree. One of the participants left the coaching group, and thus the data concerning him was not taken into account. Questionnaires, observational data, thematic and phone interviews were the primary means of data collection. The data analysis focused on examining how the participants reached the goals set at the beginning of the group coaching project, how they engaged in the group activities and how their plans made for the autumn 2010 materialized. The thesis also attempted to shed light onto the present situation of the availability of activities for young people without any vocational degrees. The results indicated that the participants had become activated in planning their own lives. All of the four participants reached their goals. They were able to determine their preferred fields of study and applied for schools via the joint application system in the spring 2010. The second goal of restoring the daily rhythm was not realized. The participants’ engagement in group coaching proved to be poor. In the autumn 2010 two out of the four participants started studying in the school of their preference. The rest were left without a study place. One of them entered another coaching group, and the other one planned to proceed with the old studies. In conclusion it could be claimed that a variety of group activities aid school drop-outs in becoming activated in making plans about their lives

A graph of dark energy significance on different spatial and mass scales

The current cosmological paradigm sees the formation and evolution of the cosmic large-scale structure as governed by the gravitational attraction of the Dark Matter (DM) and the repulsion of the Dark Energy (DE). We characterize the relative importance of uniform and constant dark energy, as given by the Lambda term in the standard LCDM cosmology, in galaxy systems of different scales, from groups to superclusters. An instructive "Lambda significance graph" is introduced where the matter-DE density ratio /rho_Lambda for different galaxy systems is plotted against the radius R. This presents gravitation and DE dominated regions and shows directly the zero velocity radius, the zero-gravity radius, and the Einstein-Straus radius for any fixed value of mass. Example galaxy groups and clusters from the local universe illustrate the use of the Lambda significance graph. These are generally located deep in the gravity-dominated region /rho_Lambda > 2, being virialized. Extended clusters and main bodies of superclusters can reach down near the border line between gravity-dominated and DE dominated regions /rho_Lambda = 2. The scale--mass relation from the standard 2-point correlation function intersects this balance line near the correlation lenght. The log /rho_Lambda vs. log R diagram is a useful and versatile way to characterize the dynamical state of systems of galaxies within the Lambda dominated expanding universe.Comment: 4 pages, 2 figure

Development and optimization of a novel sustained-release dextran tablet formulation for propranolol hydrochloride

A novel oral controlled delivery system for propranolol hydrochloride (PPL) was developed and optimized. The in vitro dissolution profiles of sustained-release matrix tablets of racemic PPL were determined and compared with the United States Pharmacopeia (USP) tolerance specifications for Propranolol Hydrochloride Extended-Release Capsules. The influence of matrix forming agents (native dextran, hydroxypropyl methylcellulose (HPMC), cetyl alcohol) and binary mixtures of them on PPL release in vitro was investigated. A central composite design was applied to the optimization of a sustained-release tablet formulation. The sustained-release matrix tablets with good physical, mechanical and technological properties were obtained with a matrix excipient:PPL ratio of 60:40 (w/w), with a dextran:HPMC ratio of 4:1 (w/w) and with a cetyl alcohol amount of 15% (w/w). A comparative kinetic study of the present matrix tablets and commercial SUMIAL RETARD capsules (Spain) was established. The value for the similarity factor (f2 = 69.6) suggested that the dissolution profile of the present two sustained-release oral dosage forms are similar. Higuchi (diffusion) and Hixon–Crowell (erosion) kinetic profiles were achieved and this codependent mechanism of drug release was established

Mapping the three-body system - decay time and reversibility

In this paper we carry out a quantitative analysis of the three-body systems and map them as a function of decaying time and intial conguration, look at this problem as an example of a simple deterministic system, and ask to what extent the orbits are really predictable. We have investigated the behavior of about 200 000 general Newtonian three body systems using the simplest initial conditions. Within our resolution these cover all the possible states where the objects are initially at rest and have no angular momentum. We have determined the decay time-scales of the triple systems and show that the distribution of this parameter is fractal in appearance. Some areas that appear stable on large scales exhibit very narrow strips of instability and the overall pattern, dominated by resonances, reminds us of a traditional Maasai warrior shield. Also an attempt is made to recover the original starting conguration of the three bodies by backward integration. We find there are instances where the evolution to the future and to the past lead to different orbits, in spite of time symmetric initial conditions. This implies that even in simple deterministic systems there exists an Arrow of Time.Comment: 8 pages, 9 figures. Accepted for publication in MNRAS. Includes low-resolution figures. High-resolution figures are available as PNG