3,125 research outputs found
An empirical approach to the extragalactic background light from AEGIS galaxy SED-type fractions
The extragalactic background light (EBL) is of fundamental importance both
for understanding the entire process of galaxy evolution and for gamma-ray
astronomy. However, the overall spectrum of the EBL between 0.1 and 1000
microns has never been determined directly neither from observed luminosity
functions (LFs), over a wide redshift range, nor from any multiwavelength
observation of galaxy spectral energy distributions (SEDs). The evolving,
overall spectrum of the EBL is derived here utilizing a novel method based on
observations only. It is emphasized that the local EBL seems already well
constrained from the UV up to the mid-IR. Since different independent
methodologies such as direct measurement, galaxy counts, gamma-ray attenuation
and realistic EBL modelings point towards the same EBL intensity level. A
relevant contribution from Pop III stars to the local EBL seems unlikely.Comment: Contributed talk at the IAU 284 SED2011 Symposium, Preston, UK,
September 5-9, 2011; 4 pages, 1 figure. Online material available at
http://side.iaa.es/EB
Work Organisation and Innovation - Case Study: Company X, Slovenia
[Excerpt] Company X is one of the largest and most successful commercial grocery retailing chains in south-eastern Europe (Euromonitor, 2011). It was established over 60 years ago in Ljubljana, Slovenia. Company X is the largest Slovenian retailer with 24,000 employees and approximately a third of the market share for its sector (Gvin.com, 2012). Company X also operates in six other countries in the region: Serbia (9% market share), Croatia (9% market share), Bosnia and Herzegovina (5% market share), Montenegro (19% market share), Bulgaria (0.5% market share) and Albania (1% market share) (Company X, 2011). Company Xās main activity is retail and wholesaling of fast moving consumer goods (FMCG). The chain has been expanding its core activity by selling clothing, furniture and household appliances as well. Company X has 1,581 outlets including hypermarkets, supermarkets, convenience stores, specialised stores, etc. (Company X, 2011)
Kinetics of Deposition of Oriented Superdisks
We use numerical Monte Carlo simulation to study kinetics of deposition of
oriented superdisks, bounded by the Lame curves of the form
, on regular planar substrate. It was recently shown that
the maximum packing density, as well as jamming density , exhibit
discontinuous derivative at , when the shape changes from convex to
concave form. By careful examination of the late-stage approach to the jamming
limit, we find that the leading term in temporal development is also
nonanalytic at , and offer heuristic excluded-area arguments for this
behavior
Kultura masovne potroŔnje kao "filozofija života"
Rasprostranjeno miÅ”ljenje koje je vladalo tokom dvadesetih godina proÅ”loga veka, bilo je da su zemlje poput Sjedinjenih Država uÅ”le u doba stalnog izobilja i da masovna proizvodnja, zajedno sa unapreÄenim graÄevinarstvom ukida siromaÅ”tvo i obezbeÄuje, prvi put u istoriji, visoki životni standard svakog pojedinca. Kultura masovne potroÅ”nje koja se tada formirala ne može se lako opistati, jer napor da se opiÅ”e bilo koji period istorije ameriÄkog druÅ”tva mora da ukljuÄi u razmatranje ideje, vrednosti i ukuse koji su u to vreme bili posebno izraženi i unapreÄivani. Osvetljavanje njene snage i prave prirode može da pomogne u pružanju odgovora na jedno od osnovnih pitanja ovog rada a to je naÄin na koji se u ameriÄkom druÅ”tvu ta masovna kultura prenosila
Uloga i znaÄaj stranog kapitala u industrijalizaciji predratne Srbije
U kapitalistickoj privredi Srbije sve do Drugog svetskog rata strane investicije su najveÄim delom iÅ”le preko privatnog bankraskog sektora od nosno stvaranjem bankarsko-industrijskih koncerna. Rezultati istrazivanja ukazuju da ove investicije nisu mogle da pokrenu ubrzaniji industrijski razvoj zemlje, jer država nije bila u stanju da (usled razliÄitih druÅ”tveno-politi Äkih i ekonomskih faktora) zakonima i drugim aktivnostima zaÅ”titi i uskladi sopstvene int erese sa interesima stranih ulagaÄa. Ovaj rad posebnu pažnju posve Äuje naÄinima na koje su banke sa stranim kapitalom plasirale finansijska sredstva u razliÄite industrijske grane ali ukazuje i na pozitivne efekte koje su strane investicije imale u razvoju modernizacijskih procesa u Srbiji ovog istorijskog razdoblja
Strukturne promene u privatnom bankarskom sektoru Srbije - istorijske opomene i preporuke
Rad obuhvata važan deo istorije srpskog bankarstva u uslovima kapitalistiÄkog privrednog sistema i ukazuje na kljuÄne strukturne promene koje su uvoÄene tokom vremena - na njihov karakter, kvalitet, važnost, kao i na nedostatke; on nastoji da odgovori na pitanje Å”ta je to Å”to je posmatrano kroz delovanje ovog segmenta srpske privrede predstavljalo pa i danas predstavlja kljuÄnu koÄnicu za ubrzaniji i kvalitetniji privredni napredak druÅ”tva
Dopaminergic modulation of phenotypical and functional characteristics of human T lymphocytes: perspectives for nonconventional immunomodulation.
Dopamine (DA) besides its action in the nervous system, plays an important role in immune cells interactions. Emerging role of DA as a regulator of CD4+ T cells physiology is important since dysregulation of different T cell subsets, showing abnormal cell numbers, functions, expression of dopamine receptors (DR) and/or response to DA, could contribute to the onset and development of some immune-related disorders. Thus, directly and indirectly acting dopaminergic therapeutics, currently used in approved clinical indications, could represent an attractive source of non-conventional agents for the modulation of CD4+ T cell functions.
The aim of the present work was to develop in vitro methods to investigate the effects of dopaminergic agents, currently used in the pharmacotherapy, on the functional responses of CD4+ T cells, namely: (i) CD4+ T na\uefve (Tn), T central memory (TCM) and T effector memory (TEM) cells, and their responses to recall antigen (Ag); (ii) CD4+ T regulatory cells (Treg), and their suppressive effects on T effector cells (Teff) and (iii) CD4+ T na\uefve cells, and their ability to differentiate towards different T helper (Th) lineages (Th1/Th2/Th17).
In cultured CD4+ T cells, our results have shown higher expression of DR in apoptotic cells in comparison to viable cells and stimulation-induced DR upregulation of all DR on viable cells. Addition of high concentrations of DA and L-DOPA (100 \u3bcM) have shown profound effect on survival of CD4+ T cells. Interestingly, based on preliminary experiments, our ex vivo data have shown trend of proliferating cells expressing DR in higher percentages that still need to be validated in subsequent studies on more subjects. So far, in vitro tested concentrations of dopaminergic agonists have not shown any major effects on proliferation of CD4+ T cells.
In addition, through the use of flow cytometric analysis, expression of DR was examined on human: CD4+ na\uefve T lymphocytes (CD3+CD4+CD45RA+CCR7+), TCM (CD3+CD4+CD45RA-CCR7+), TEM (CD3+CD4+CD45RA-CCR7-), Treg cells (CD4+CD25highCD127low), and also frequency of different Th subsets: Th1 (CD4+CXCR3+CCR4-CCR6-), Th2 (CD4+CXCR3-CCR4+CCR6-), Th17 (CD4+CXCR3-CCR4-CCR6+) and Th1/Th17 (CD4+CXCR3+CCR4-CCR6+) were analysed. DR expression of all five DR was confirmed on each subset, present in a different extension potentially represents an opportunity to develop targeted immunomodulating strategies.
Validated and developed in vitro method to test functional response of memory CD4+ T cells towards recall Ag have potential relevance for a wide range of different fields of T cell biology research in health and disease. Additionally, obtained preliminary results have confirmed in vitro experimental conditions likely appropriate to study commitment of na\uefve CD4+ T cells and factors mimicking specific polarisation routes (Th1/Th2/Th17), which are T subsets important in onset and development of some dopamine-related disorders.
Further, in vitro methods have shown CD4+CD25high T cell-dependent inhibition of CD4+ T effector lymphocyte proliferation. Treg cells also suppressed production of IFN-\u3b3 and TNF-\u3b1 from Teff cells. In addition, effects of DA and L-DOPA treatments seems to suppress Treg suppressive capacity in healthy subjects and in the group of Parkinson\u2019s disease (PD) patients who had never been treated (PD-dn), but not in PD patients that were on dopaminergic therapy (PD-dt).
Available evidence supports the possibility to repurpose dopaminergic agents as modulators of dopaminergic pathways, shifting the balance towards beneficial outcomes in some pathological conditions, such as PD. Over the last decades, an impressive number of studies in the animal model of immune diseases and in the clinical setting supported this evidence, and strongly required futher testing. The development of therapeutic protocols needs to take into account that DR exists in multiple subtypes and their patterns of expression, and that fuctional relevance differs among immune cells - and may even depend on the functional status (e.g. resting/activated) of specific cells.
Proposed in vitro methods examined and characterised the various CD4+ T cell lineages, providing both the conceptual as well as the experimental framework for more in-depth investigation of dopaminergic pathways modulating CD4+ T cell function
- ā¦