The Dark Matter equation of state through cosmic history

Cold Dark Matter (CDM) is a crucial constituent of the current concordance cosmological model. Having a vanishing equation of state (EoS), its energy density scales with the inverse cosmic volume and is thus uniquely described by a single number, its present abundance. We test the inverse cosmic volume law for Dark Matter (DM) by allowing its EoS to vary independently in eight redshift bins in the range $z=10^5$ and $z=0$. We use the latest measurements of the Cosmic Microwave Background radiation from the Planck satellite and supplement them with Baryon Acoustic Oscillation (BAO) data from the 6dF and SDSS-III BOSS surveys, and with the Hubble Space Telescope (HST) key project data. We find no evidence for nonzero EoS in any of the eight redshift bins. With Planck data alone, the DM abundance is most strongly constrained around matter-radiation equality $\omega^{\rm eq}_g = 0.1193^{+0.0036}_{-0.0035}$ (95% c.l.), whereas its present day value is more weakly constrained $\omega^{(0)}_g = 0.16^{+0.12}_{-0.10}$ (95% c.l.). Adding BAO or HST data does not significantly change the $\omega^{\rm eq}_g$ constraint, while $\omega^{(0)}_g$ tightens to $0.160^{+0.069}_{-0.065}$ (95% c.l.) and $0.124^{+0.081}_{-0.067}$ (95% c.l.) respectively. Our results constrain for the first time the level of "coldness" required of the DM across various cosmological epochs and show that the DM abundance is strictly positive at all times.Comment: 6 pages, 4 figures, changed color scheme for figure

Revealing the nature of central emission nebulae in the dwarf galaxy NGC 185

In this paper we present new optical observations of the galaxy NGC 185 intended to reveal the status of supernova remnants (SNRs) in this dwarf companion of the Andromeda galaxy. Previously, it was reported that this galaxy hosts one SNR. Our deep photometric study with the 2m telescope at Rozhen National Astronomical Observatory using narrow-band H$\alpha$ and [SII] filters revealed complex structure of the interstellar medium in the center of the galaxy. To confirm the classification and to study the kinematics of the detected nebulae, we carried out spectroscopic observations using the SCORPIO multi-mode spectrograph at the 6m telescope at the Special Astrophysical Observatory of the Russian Academy of Science, both in low- and high-resolution modes. We also searched the archival X-ray and radio data for counterparts of the candidate SNRs identified by our optical observations. Our observations imply the presence of one more SNR, one possible HII region previously cataloged as part of an SNR, and the presence of an additional source of shock ionization in one low-brightness PN. We detected enhanced [SII]/H_alpha and [NII]/H_alpha line ratios, as well as relatively high (up to 90 km s$^{-1}$) expansion velocities of the two observed nebulae, motivating their classification as SNRs (with diameters of 45 pc and 50 pc), confirmed by both photometric and spectral observations. The estimated electron density of emission nebulae is 30 - 200 cm$^{-3}$. Archival XMM-Newton observations indicate the presence of an extended, low-brightness, soft source in projection of one of the optical SNRs, whereas the archival VLA radio image shows weak, unresolved emission in the center of NGC 185.Comment: 15 pages, 14 figures, accepted for publication in A&

Serum Fas/FasL levels in dependence on clinical presentations of coronary disease and their relationship with risk factors

Background/Aim. Ischemic heart disease is mostly a consequence of atherosclerosis. Besides the inflammation, the Fas/Fas ligand (FasL)/caspase death pathway is documented to be activated in atherosclerotic lesions. The aim of this study was to compare the values of soluble forms of Fas and FasL in patients with different presentations of coronary disease and to correlate Fas/FasL with risk factors. Methods. We studied 30 patients with chronic stable angina pectoris (SAP), 27 with non-stable angina pectoris (NSAP), and 39 with acute ST-elevation myocardial infarction (STEMI) and 27 age-matched healthy volunteers (the control group). Serum Fas/APO1 and FasL concentrations were determined using a commercially available enzymelinked immunoassays (ELISA). Results. Fas/APO-1 levels in the STEMI patients (6.981 ± 2.689 ng/mL) were significantly higher than Fas levels in the controls (5.092 ± 1.252 ng/mL, p < 0.01), but not significantly higher than Fas values in the SAP (5.952 ± 2.069 ng/mL) and the USAP patients (5.627±2.270 ng/ml). Levels of FasL did not show any significant difference among the studied groups. In the SAP patients Fas/APO1 showed a significant positive correlation with high sensitivity C-reactive protein (hsCRP) (p < 0.05) and a negative correlation with high-density lipoprotein cholesterol (HDL-C) (p < 0.05), while FasL showed a significant positive correlation with low-density lipoprotein cholesterol (LDL-C) (p < 0.05). Fas levels between the patients having cholesterol within normal range and those whose cholesterol was above the normal range showed a significant difference (p < 0.05) only in the NSAP patients. Fas and FasL levels between the patients with hsCRP lower than 3.0 mg/L and those with hsCRP higher than 3.0 mg/L of the SAP group showed a significant differences (p < 0.001, p < 0.05, respectively). Strong correlation between Fas concentration and diabetes mellitus (p < 0.05) and FasL concentrations and both cholesterol (p < 0.01) and triglycerides (p < 0.01) in the NSAP patients was observed. The patients in the SAP group showed no strong correlation between Fas and FasL concentration and risk factors. Conclusions. The obtained results showed that apoptotic process is dysregulated in the patients with ischemic heart disease. Interdependence between Fas and FasL and inflammatory and lipid markers as well as with cardiovascular risk factors was established

Roncus ivansticae (Neobisiidae, Pseudoscorpiones): A new epigean species from eastern Serbia

A single species of Roncus L. Koch, 1873, which was collected in eastern Serbia and is new to science (R. ivansticae n. sp.) is described herein; the diagnostic characters are illustrated and their distribution is provided. The possible establishment of two species (or supraspecific?) groups of Roncus is presented briefly in view of the importance of some diagnostic characters

The physics of the B Factories

“The Physics of the B Factories” describes a decade long effort of physicists in the quest for the precise determination of asymmetry — broken symmetry — between particles and anti-particles. We now recognize that the matter we see around us is the residue — one part in a billion — of the matter and antimatter that existed in the early universe, most of which annihilated into the cosmic background radiation that bathes us. But the question remains: how did the baryonic matter-antimatter asymmetry arise? This book describes the work done by some 1000 physicists and engineers from around the globe on two experimental facilities built to test our understanding of this phenomenon, one at the SLAC National Accelerator Laboratory in California, USA, and a second at the KEK Laboratory, Tsukuba, Japan, and what we have learned from them in broadening our understanding of nature. Why is our universe dominated by the matter of which we are made rather than equal parts of matter and antimatter? This question has puzzled physicists for decades. However, this was not the question we addressed when we wrote the paper on CP violation in 1972. Our question was whether we can explain the CP violation observed in the K meson decay within the framework of the renormalizable gauge theory. At that time, Sakharov’s seminal paper was already published, but it did not attract our attention. If we were aware of the paper, we would have been misled into seeking a model satisfying Sakharov’s conditions and our paper might not have appeared. In our paper, we discussed that we need new particles in order to accommodate CP violation into the renormalizable electroweak theory, and proposed the six-quark scheme as one of the possible ways introducing new particles. We thought that the six-quark scheme is very interesting, but it was just a possibility. The situation changed when the tau-lepton was found and it was followed by the discovery of the Upsilon particle. The existence of the third generation became reality. However, it was still uncertain whether the mixing of the six quarks is a real origin of the observed CP violation. Theoretical calculation of CP asymmetries in the neutral K meson system contains uncertainty from strong interaction effects. What settled this problem were the B Factories built at SLAC and KEK. These B Factories are extraordinary in many ways. In order to fulfill the requirements of special experiments, the beam energies of the colliding electron and positron are asymmetric, and the luminosity is unprecedentedly high. It is also remarkable that severe competition between the two laboratories boosted their performance. One of us (M. Kobayashi) has been watching the development at KEK very closely as the director of the Institute of Particle and Nuclear Studies of KEK for a period of time. As witnesses, we appreciate the amazing achievement of those who participated in these projects at both laboratories. The B Factories have contributed a great deal to our understanding of particle physics, as documented in this book. In particular, thanks to the high luminosity far exceeding the design value, experimental groups measured mixing angles precisely and verified that the dominant source of CP violation observed in the laboratory experiments is flavor mixing among the three generations of quarks. Obviously we owe our Nobel Prize to this result. Now we are awaiting the operation of the next generation Super B Factories. In spite of its great success, the Standard Model is not an ultimate theory. For example, it is not thought to be possible for the matter dominance of the universe to be explained by the Standard Model. This means that there will still be unknown particles and unknown interactions. We have a lot of theoretical speculations but experimental means are rather limited. There are great expectations for the Super B Factories to reveal a clue to the world beyond the Standard Model

2D simulation and analysis of fluid flow between two sinusoidal parallel plates using lattice Bolzmann method

In order to obtain a better heat transfer, it is important to enhance fluid mixing in heat exchangers. Since there are negative effects when heat exchangers are operating in turbulent regime (like significant pressure drop, increased size of the pump) it is necessary to apply the techniques which would provide better fluid mixing when heat exchangers are operating in laminar regime. Investigations have shown that use of sinusoidal instead of flat plates results in this effect. This study is a result of two dimensional simulation of fluid flow between two parallel sinusoidal plates. Simulation was done with the use of modified Openlb code, based on lattice Boltzmann method. Reynolds number was varied from 200 to 1000, and space between the plates was varied from 3cm to 5 cm. Results showed that sinusoidal plates enhance fluid mixing, especially with greater values of Re and smaller space between the plates, which is in agreement with previous investigations

Jet Energy Density in Hadron-Hadron Collisions at High Energies

The average particle multiplicity density dN/deta is the dynamical quantity which reflects some regularities of particle production in low-pT range. The quantity is an important ingredient of z-scaling. Experimental results on charged particle density are available for pp, pA and AA collisions while experimental properties of the jet density are still an open question. The goal of this work is to find the variable which will reflect the main features of the jet production in low transverse energy range and play the role of the scale factor for the scaling function psi(z) and variable z in data z-presentation. The appropriate candidate is the variable we called "scaled jet energy density". Scaled jet energy density is the probability to have a jet with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of scaled jet energy density in proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and at eta = 0. The properties of the new variable are discussed and sensitivity to "physical scenarios" applied in the standard Monte Carlo generator is noted. The results of scaled jet energy density at LHC energies are presented and compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics & Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200

Graphene-based waveguide resonators for submillimeter-wave applications

Utilization of graphene covered waveguide inserts to form tunable waveguide resonators is theoretically explained and rigorously investigated by means of full-wave numerical electromagnetic simulations. Instead of using graphene-based switching elements, the concept we propose incorporates graphene sheets as parts of a resonator. Electrostatic tuning of the graphene surface conductivity leads to changes in the electromagnetic field boundary conditions at the resonator edges and surfaces, thus producing an effect similar to varying the electrical length of a resonator. The presented outline of the theoretical background serves to give phenomenological insight into the resonator behavior, but it can also be used to develop customized software tools for design and optimization of graphene-based resonators and filters. Due to the linear dependence of the imaginary part of the graphene surface impedance on frequency, the proposed concept was expected to become effective for frequencies above 100 GHz, which is confirmed by the numerical simulations. A frequency range from 100 GHz up to 1100 GHz, where the rectangular waveguides are used, is considered. Simple, all-graphene-based resonators are analyzed first, to assess the achievable tunability and to check the performance throughout the considered frequency range. Graphene–metal combined waveguide resonators are proposed in order to preserve the excellent quality factors typical for the type of waveguide discontinuities used. Dependence of resonator properties on key design parameters is studied in detail. Dependence of resonator properties throughout the frequency range of interest is studied using eight different waveguide sections appropriate for different frequency intervals. Proposed resonators are aimed at applications in the submillimeter-wave spectral region, serving as the compact tunable components for the design of bandpass filters and other devices

Znanje i stavovi beogradskih studenata medicine i stomatologije o upravljanju medicinskim otpadom

Introduction/Objective Knowledge and practical skills in medical waste (MW) management are of equal importance for medical and dental doctors. The first comparative study on the knowledge and skills in the field of MW management among Belgrade students was conducted with the goal of examining whether students of medicine and dentistry are equally familiar with this extremely important field. Methods a cross-sectional study included 558 students of the sixth year of studies (430 medical and 128 dental students) who completed an anonymous semi-structured questionnaire to determine attitudes and knowledge on MW management. Results the majority of medical and dental students had no training in MW management (79.5% and 74.6%, respectively). Dental students use protective equipment more frequently than medical students (94.5% vs. 42%, p lt 0.001). However, full vaccinal protection against hepatitis B is better among medical students compared to dental students (57.7% vs. 39.1%, p lt 0.001). Complete knowledge on postexposal prophylaxis is better among medical students compared to dental students (44.5% vs. 13.3%, p lt 0.001). However, dental students are more disciplined in reporting injuries (63.1% vs. 52.4%, p = 0.038). The students' knowledge on primary separation of infectious waste (93% vs. 77.8%, p lt 0.001) and used needles (80.3% vs. 70.4%, p = 0.007) is better among dental students compared to medical students' correct answers. Conclusion Dental students show better knowledge on MW management and are more disciplined in using personal infection protection compared to medical students. The students support continued training on MW management and investigations on this topic.Uvod/Cilj Znanje i praktične veštine upravljanja medicinskim otpadom su od posebnog značaja za doktore medicine i stomatologije. Komparativna studija o znanju i veštinama iz oblasti upravljanja medicinskim otpadom sprovedena je među beogradskim studentima prvi put, u cilju ispitivanja da li ovom izuzetno važnom oblašću studenti medicine i stomatologije vladaju podjednako dobro. Metode Ova studija preseka obuhvatila je 558 studenata šeste godine studija na Beogradskom univerzitetu (430 studenata medicine i 128 studenata stomatologije), koji su popunili anonimni upitnik o znanju i stavovima o upravljanju medicinskim otpadom. Rezultati Većina studenata stomatologije i medicine nisu imali nikakvu posebnu obuku iz upravljanja medicinskim otpadom (79,5% i 74,6%). Studenti stomatologije su češće koristili zaštitnu opremu (94,5% prema 42%, p lt 0,001). Vakcinalna zaštita od hepatitisa B je kompletnija među studentima medicine u odnosu na studente stomatologije (57,7% prema 39,1%, p lt 0,001). Znanje o profilaksi posle izloženosti bolja je među studentima medicine (44,5% prema 13,3%, p lt 0,001). Međutim, studenti stomatologije su ažurniji u pogledu prijavljivanja povreda na radnom mestu (63,1% prema 52,4%, p = 0,038). Znanje studenata o primarnoj separaciji infektivnog otpada i korišćenih igala je bolje među budućim stomatolozima (tačni odgovori 93% nasuprot 77,8%; p lt 0,001 i 80,3% prema 70,4%; p = 0,007). Zaključak Studenti stomatologije imaju bolje znanje o upravljanju medicinskim otpadom i disciplinovaniji su u pogledu korišćenja zaštitne opreme na radu u odnosu na studente medicine. Studenti podržavaju kontinuiranu edukaciju o upravljanju medicinskim otpadom i dalja istraživanja o ovoj temi