STAR results and perspectives on transverse spin asymmetries

The STAR collaboration reported precision measurements on the transverse single spin asymmetries for the production of forward $\pi^0$ mesons from polarized proton collisions at $\sqrt{s}=$ 200 GeV. To disentangle contributions to measured forward asymmetries one has to look beyond inclusive $\pi^0$ production to the production of forward jets or direct photons. In 2006, STAR with the Forward Pion Detector++ (FPD++) in place, collected 6.8 pb$^{-1}$ of forward data with an average polarization of 60%. FPD++ had sufficient acceptance for "jet-like" objects, which are clustered responses of an electromagnetic calorimeter primarily sensitive to incident photons, electrons and positrons. For these objects, the angle of the outgoing leading $\pi^0$ with respect to the fragmenting parton was reconstructed, thus enabling us to disentangle the contributions to the forward $\pi^0$ asymmetries. The simulated data set shows that on average there are approximately 2.5 fragmenting mesons per one "jet-like" object, making them reasonably "jetty". Preliminary results provide no evidence of measured contributions to the asymmetry from jet fragmentation, implying the Sivers distribution functions play a substantial role in producing the large inclusive forward $\pi^0$ asymmetries. A similar effort was made in the mid-rapidity $(|\eta|<1)$ region of the STAR detector, where 2.2 pb$^{-1}$ of data was collected. We present progress made by making measurements of the azimuthal asymmetry of leading charged pions in jets produced by transversely polarized proton collisions.Comment: 6 pages, 4 figures, proceedings of the Transversity 2011 worksho

Improved FPT algorithms for weighted independent set in bull-free graphs

Very recently, Thomass\'e, Trotignon and Vuskovic [WG 2014] have given an FPT algorithm for Weighted Independent Set in bull-free graphs parameterized by the weight of the solution, running in time $2^{O(k^5)} \cdot n^9$. In this article we improve this running time to $2^{O(k^2)} \cdot n^7$. As a byproduct, we also improve the previous Turing-kernel for this problem from $O(k^5)$ to $O(k^2)$. Furthermore, for the subclass of bull-free graphs without holes of length at most $2p-1$ for $p \geq 3$, we speed up the running time to $2^{O(k \cdot k^{\frac{1}{p-1}})} \cdot n^7$. As $p$ grows, this running time is asymptotically tight in terms of $k$, since we prove that for each integer $p \geq 3$, Weighted Independent Set cannot be solved in time $2^{o(k)} \cdot n^{O(1)}$ in the class of $\{bull,C_4,\ldots,C_{2p-1}\}$-free graphs unless the ETH fails.Comment: 15 page

Causes of lawn and ornamental plants degradation at the Patriotic War Memorial Cemetery in Vukovar

Provedena istraživanja imala su za cilj utvrditi razloge propadanja travnjaka i ukrasnog bilja na Memorijalnom groblju žrtava Domovinskog rata u Vukovaru. U tu svrhu otvorena su tri reprezentativna pedološka profila iz kojih su uzeti uzorci tla za fizikalne i kemijske analize te sedam prosječnih uzoraka tla u kojima su određena kemijska svojstva tla te biljno hranidbeni kapacitet tla. Određivanje fizikalnih i kemijskih svojstava tla obavljeno je u Zavodu za ishranu bilja Agronomskog fakulteta Sveučilišta u Zagrebu standardnim analitičkim metodama. Na temelju provedenih istraživanja fizikalno-kemijskih svojstava tla utvrđeni su značajni propusti u pripremi tla i uzgojnog supstrata za biljke. To se prvenstveno odnosi na slabu dreniranost tla što uzrokuje površinsko stagniranje oborinskih i drugih voda, zbog pojave nepropusnog sloja tla i zbijenost tla u vrijeme sušnog razdoblja. Također su utvrđena vrlo nepovoljna fizikalna i kemijska svojstva tla (visoka pH vrijednost), a relativno niski biljno-hranidbeni kapacitet tla. Zbog vrlo slabe propusnosti tla, potrebno je postaviti sustav cijevne drenaže koji će omogućiti odvođenje suvišne vode u pojedinim razdobljima godine. Unošenjem većih količina organske tvari (treseta cca 4-5 L/m2 i zrelog stajskog gnojiva cca 4-5 kg/m2) i pijeska te dobrim miješanjem s postojećim tlom, povećat će se propusnost, kapacitet tla za zrak i vodu i stabilnost strukture, a umanjit će se specifična masa tla volumna i zbijenost tla. Povoljna pH reakcija tla za određenu kulturu može se postići unošenjem različitih količina treseta odgo-varajuće pH vrijednosti. Osnovnom gnojidbom s većim količinama mineralnih gnojiva, poglavito fosfornih, povećava se fond pristupačnih hraniva u tlu.The aim of the research was to find the reasons for lawn and ornamental plants degradation at the Patriotic War Memorial Cemetery in Vukovar. For this purpose, three representative pedological profiles were opened, from which soil samples were taken for physical and chemical analyses. Seven average soil samples were also taken for determining soil chemical properties and the plant nutrition capacity. Physical and chemical properties of the soil were analyzed in the Department of Plant Nutrition, Faculty of Agriculture, University of Zagreb, by standard analytical methods. Analyses of the soil physical and chemical properties revealed considerable oversights in the soil and substrate preparation for cultivation. This primarily applies to poor soil drainage, which caused surface retention of precipitation and other waters because of the formation of a soil layer impervious to water and compactness during the dry period. Excessively high soil reaction (pH value) was also recorded as well as a relatively low plant nutrition capacity. Due to very poor soil permeability, a pipe drainage system should be installed to enable draining of surplus water that appears in some parts of the year. Higher amounts of organic matter (cca 4-5 L/m2 peat and ca 4-5 kg/m2 ripe manure) and sand well mixed with the existing soil will increase the soil permeability, air capacity and structure stability. Specific soil volume and compactness will also be reduced. Acid Lithuanian peat will lower the pH value, while higher mineral fertilizer (mainly phosphorus) rates will raise the levels of available nutrients in soil

Investigating biosecurity risks associated with the delivery of feed to swine farms

Introduction Biosecurity protocols reduce the introduction and spread of pathogens among swine farms. For pigs, biosecurity ensures market stability, maintains export opportunities, and controls spread of production and public health diseases. Salmonella, the second most common cause of bacterial foodborne illness, causes gastrointestinal illness. Pigs can be asymptomatic carriers of the bacteria and pork products are a known source of salmonellosis in humans. Salmonella have been isolated from pigs, boots, flies, rodents, bird feces, feed, feed-ingredients, and feed trucks. The objective was to identify management factors to reduce the risk of disease spread among swine farms through feed trucks. Materials and Methods The study was conducted in two phases - the first phase included a series of focus groups and key-informant interviews; discussions held with swine producers and feed company personnel explored the protocols currently in place that reduce the risk of disease spread through the delivery of feed. Participants were asked to identify possible management changes that could further reduce the risk, and to rate these ideas in terms of their effect on disease control, and feasibility based on implementation and economics. This information was used to structure the second phase of the study – a pilot study. The pilot study was conducted over 6 weeks in the winter of 2013, and included 40 feed truck drivers from 3 Ontario feed companies. Truck drivers filled out log sheets as they delivered feed to swine farms, and provided information about the prevalence of the identified biosecurity risks during the day-to-day delivery of feed. Drivers were randomly assigned to be in either the treatment or control groups. Drivers in the control group delivered feed as they normally do. Drivers in the treatment group were: i) asked not to enter the barn unless absolutely necessary, and ii) were provided with re-usable, washable rubber over-shoes and were asked to wear a clean pair at each farm when they felt safe doing so. Chisquared tests were used to compare the usage of clean boots between drivers in the treatment and control groups. In total, 40 drivers from 3 companies, delivering feed to 2202 farms over 6 weeks (in the winter) collected descriptive data on the factors and compared use of different boots. Results The factors followed by the proportion of farms and drivers where the factor was found were found as follows: Most farms were: keeping areas (driveway, feed bin and barnyard) clean of mud and manure (82%), and dead-stock (91%) was appropriately disposed of and not visible to the driver. Some farms had an outbuilding to deliver bagged feed (24%). Other factors that were identified that producers should work on were to provide farm boots and coveralls for the driver if the driver needed to go into the barn, ordering the correct amount of feed to decrease the numbers of deliveries (or frequencies of deliveries) of feed, and notifying feed mill of a disease outbreak on the farm. Feed truck driver factors included wearing a separate pair of clean, disinfected, dried boots (25%) and gloves (50%) at each farm that is visited (even if the driver does not go into the barn, remaining outside the barn (92%); washing the steering wheel (49%), floor mat (77%) and outside of the truck (32%) every 24 hours. From these results, it may be advisable to increase the frequency of washing the truck. Another factor identified was for the driver to know and follow the farm biosecurity protocols. Half of the time, the driver left the feed bill outside barn (54%). Drivers given disinfected rubber boots were more likely to wear these on farms (42%) than plastic disposable boots (4%) (P<0.05). These drivers were also more likely to wear disinfected rubber boots than the control drivers (11%) (P<0.001). Conclusions and Discussion Biosecurity is a responsibility that is shared among all members of the industry. Feed personnel were encouraged to know more about disease transmission. Acknowledgments Canadian Swine Health Board for funding, feed company personnel and producers for participation

Measurement of prompt D0, D+, D*+, and D+S production in p–Pb collisions at √sNN = 5.02 TeV

The measurement of the production of prompt D0, D+, D*+, and D+S mesons in proton–lead (p–Pb) collisions at the centre-of-mass energy per nucleon pair of √sNN = 5.02 TeV, with an integrated luminosity of 292 ± 11 μb−1, are reported. Differential production cross sections are measured at mid-rapidity (−0.96 &lt; ycms&lt; 0.04) as a function of transverse momentum (pT) in the intervals 0 &lt; pT&lt; 36 GeV/c for D0, 1 &lt; pT&lt; 36 GeV/c for D+ and D*+, and 2 &lt; pT&lt; 24 GeV/c for D+ mesons. For each species, the nuclear modification factor RpPb is calculated as a function of pT using a proton-proton (pp) ref- erence measured at the same collision energy. The results are compatible with unity in the whole pT range. The average of the non-strange D mesons RpPb is compared with theoretical model predictions that include initial-state effects and parton transport model predictions. The pT dependence of the D0, D+, and D*+ nuclear modification factors is also reported in the interval 1 &lt; pT&lt; 36 GeV/c as a function of the collision centrality, and the central-to-peripheral ratios are computed from the D-meson yields measured in different centrality classes. The results are further compared with charged-particle measurements and a similar trend is observed in all the centrality classes. The ratios of the pT-differential cross sections of D0, D+, D*+, and D+S mesons are also reported. The D+S and D+ yields are compared as a function of the charged-particle multiplicity for several pT intervals. No modification in the relative abundances of the four species is observed with respect to pp collisions within the statistical and systematic uncertainties

Multiplicity dependence of (anti-)deuteron production in pp collisions at √s=7 TeV

In this letter, the production of deuterons and anti-deuterons in pp collisions at √s=7 TeV is studied as a function of the charged-particle multiplicity density at mid-rapidity with the ALICE detector at the LHC. Production yields are measured at mid-rapidity in five multiplicity classes and as a function of the deuteron transverse momentum (pT). The measurements are discussed in the context of hadron-coalescence models. The coalescence parameter B2, extracted from the measured spectra of (anti-)deuterons and primary (anti-)protons, exhibits no significant pT-dependence for pT &lt; 3 GeV/c, in agreement with the expectations of a simple coalescence picture. At fixed transverse momentum per nucleon, the B2 parameter is found to decrease smoothly from low multiplicity pp Pb-Pb collisions, in qualitative agreement with more elaborate coalescence models. The measured mean transverse momentum of (anti-)deuterons in pp is not reproduced by the Blast-Wave model calculations that simultaneously describe pion, kaon and proton spectra, in contrast to central Pb-Pb collisions. The ratio between the pT-integrated yield of deuterons to protons, d/p, is found to increase with the charged-particle multiplicity, as observed in inelastic pp collisions at different centre-of-mass energies. The d/p ratios are reported in a wide range, from the lowest to the highest multiplicity values measured in pp collisions at the LHC

Scattering Studies with Low-Energy Kaon-Proton Femtoscopy in Proton-Proton Collisions at the LHC

The study of the strength and behavior of the antikaon-nucleon (¯KN) interaction constitutes one of the key focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of (K+p⊕K−¯p) and (K−p⊕K+¯p) pairs measured in pp collisions at √s=5, 7, and 13 TeV are reported. A structure observed around a relative momentum of 58 MeV/c in the measured correlation function of (K−p⊕K+¯p) with a significance of 4.4σ constitutes the first experimental evidence for the opening of the (¯K0n⊕K0¯n) isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to Jülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the ¯KN threshold for low-energy QCD chiral models