On the limited amplitude resolution of multipixel Geiger-mode APDs

The limited number of active pixels in a Geiger-mode Avalanche Photodiode (G-APD) results not only in a non-linearity but also in an additional fluctuation of its response. Both these effects are taken into account to calculate the amplitude resolution of an ideal G-APD, which is shown to be finite. As one of the consequences, the energy resolution of a scintillation detector based on a G-APD is shown to be limited to some minimum value defined by the number of pixels in the G-APD.Comment: 5 pages, 3 figure

Участие антиоксидантной защитной системы базилика в кросс-адаптации при комплексном действии УФ-В и засоления

The 10 min UV-B irradiation (12 dj/m2) and 100mM NaCl action on medical plants Ocimum basilicum L., grown in water culture, was studying. The plants treated by UV-B irradiation were more resistent to salinity. There were two groups of compounds. One - proline, carotinoids, phenols are accumulated under salinity conditions. Second group - pigments - antocyans and flavones. Its biosynthesis is stimulated by UV-B irradiation. Under complex stressor action pigments were increased and this increasing helped plants to overcome the high salinity. The antioxidant enzyme superoxid dismutase did not play essential role in adaptive response. The low molecular weight antioxidants were more effective for formation of adaptation response. The peroxidase activity had not correlation with superoxid dismutase activity and we supposed that H2O2 could be result of other process and served as signal molecul.На основании полученных данных можно сделать главный вывод о том, что обработка УФ-В в течение 10 мин. способствовала адаптации растений базилика к действию 100 мМ NaCl. Улучшение адаптационной способности базилика при совместном действии УФ-В и засоления и связано со стимулированием биосинтеза пигментов и низкомолекулярных антиоксидантов УФ-В облучением

Оценка антиоксидантного потенциала лекарственных растений при действии Уф-B-облучения

The UV-B irradiation action (6 -36,9 dg/m2) on medical plants Artemisia lerchiana L., Nigella sativa L., Ocimum basilicum L., grown in water culture, was studying. In plant leaves and roots the content of malondialdehyde, pigments, phenols, flavonoids, proline, and activities of antioxidant enzymes were determined. Investigated plants were able to resist to action of UV-B-irradiation (low and middle dose) without any power input for increasing of biosynthesis of low and high molecular component of antioxidant defense system. The damage level under stress conditions was low. At first hours plants used the constitutive level of antioxidants and after 24 h it was needed the antioxidant pool refilling. Carotinoids, flavonoids and proline were used by plants in 4 h after irradiation, the antocian synthesis increased after 12 h.В статье рассматривается методика изучения действия УФ-B-облучения (6,0, 12,3 и 36,9 Дж/кв. м) на лекарственные растения: полынь Artemisia lerchiana L., чернушку Nigella sativa L., базилик Ocimum basilicum L., выращенные в водной культуре в условиях фитотрона. Исследованные растения способны адаптироваться к действию низкой и средней доз УФ-B-радиации без значительных энергозатрат на усиление биосинтеза как низкомолекулярных компонентов антиоксидантной защиты, так и высокомолекулярных. Степень повреждения растений при действии данного стрессора незначительна. В первые часы растения в основном использовали конститутивный уровень антиоксидантов, и лишь через 24 часа требовалось пополнение их пула. Каротиноиды, флавоноиды и пролин используются растениями уже через 4 часа после облучения, синтез антоцианов усиливается через 12 ч

Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

We present first measurements of the $\phi$-meson elliptic flow ($v_{2}(p_{T})$) and high statistics $p_{T}$ distributions for different centralities from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the $v_{2}$ of the $\phi$ meson is consistent with the trend observed for mesons. The ratio of the yields of the $\Omega$ to those of the $\phi$ as a function of transverse momentum is consistent with a model based on the recombination of thermal $s$ quarks up to $p_{T}\sim 4$ GeV/$c$, but disagrees at higher momenta. The nuclear modification factor ($R_{CP}$) of $\phi$ follows the trend observed in the $K^{0}_{S}$ mesons rather than in $\Lambda$ baryons, supporting baryon-meson scaling. Since $\phi$-mesons are made via coalescence of seemingly thermalized $s$ quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

Measurement of Transverse Single-Spin Asymmetries for Di-Jet Production in Proton-Proton Collisions at s=200\sqrt{s} = 200 GeV

We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity ($-1 \leq \eta \leq +2$) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering (SIDIS). We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in SIDIS and forward hadron production in pp collisions.Comment: 6 pages total, 1 Latex file, 3 PS files with figure

Energy dependence of charged pion, proton and anti-proton transverse momentum spectra for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV. Data are presented at mid-rapidity (|y| < 0.5) for 0.2 < pT < 12 GeV/c. In the intermediate pT region (2 < pT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT >7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at \sqrt{s_NN} = 62.4 GeV peak at pT ~ 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT > 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.Comment: 19 pages and 6 figure

The origins and spread of domestic horses from the Western Eurasian steppes

Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region.Domestication of horses fundamentally transformed long-range mobility and warfare(1). However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling(2-4) at Botai, Central Asia around 3500 bc(3). Other longstanding candidate regions for horse domestication, such as Iberia(5) and Anatolia(6), have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association(7) between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc(8,9) driving the spread of Indo-European languages(10). This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture(11,12).Descriptive and Comparative Linguistic

The origins and spread of domestic horses from the Western Eurasian steppes

Domestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 bc. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture

Exogenous proline modifies differential expression of superoxide dismutase genes in UV-B-irradiated Salvia officinalis plants

Grown in water culture 6-week-old Salvia officinalis plants with 4-5 true leaves were exposed to irradiation with UV-B (10 min, 12. 3 kJ/m2), subjected to 5 mM exogenous proline in the nutrient solution, and treated with a combination of both factors. The plants responded to short UV-B irradiation by the appearance of oxidative stress, which was manifested in elevated content of malondialdehyde in leaves. Exogenous proline added 24 h before the irradiation inhibited lipid peroxidation. The total activity of superoxide dismutase (SOD) was analyzed in plant leaves, and three SOD isoforms-Mn-SOD, Fe-SOD, and Cu/Zn-SOD-were identified. Activities of these isoforms were measured over time, and the expression of their respective genes was analyzed by reverse transcription polymerase chain reaction (RT-PCR). It is shown that the addition of proline, UV-B irradiation, or combination of both treatments regulated in a differential manner the activities of SOD isoforms localized in various cell compartments. The activity of the cytosolic Cu/Zn-SOD isoform was limited by the presence of its mRNA, the content of which was regulated by mRNA synthesis or decay rate. By contrast, the activity of plastidic Fe-SOD isoform was regulated on the substrate (allosteric) level, not on the level of FSD gene expression. The activity of mitochondrial Mn-SOD isoform was insensitive to UV-B irradiation, addition of proline, or combination of both treatments, even though the level of MSD gene transcripts increased significantly after UV-B irradiation. The results indicate that MSD gene transcripts induced by UV-B were not completely processed to produce mature mRNA or mature mRNA was not capable of translation. It cannot be excluded that the synthesized macromolecule, the Mn-SOD precursor did not undergo posttranslational maturation to produce biologically active enzyme molecules. It appears that proline is involved in the differentially regulated complex expression of various SOD isoforms. This regulation is largely based on various extents of oxidative stress in different cell compartments. © 2011 Pleiades Publishing, Ltd