Observation of the Ωb- baryon and measurement of the properties of the Ξb- and Ωb- baryons

We report the observation of the bottom, doubly-strange baryon Omega^-_b through the decay chain Omega^-_b -> J/psi Omega^-, where J/psi -> mu^+ mu^-, Omega^- -> Lambda K^-, and Lambda -> p pi^-, using 4.2 fb^{-1} of data from p\bar p collisions at sqrt{s}=1.96 TeV, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is 4.0 * 10^{-8}, or 5.5 Gaussian standard deviations. The Omega^-_b mass is measured to be 6054.4 +/- 6.8 (stat.) +/- 0.9 (syst.) MeV/c^2. The lifetime of the Omega^-_b baryon is measured to be 1.13^{+0.53}_{-0.40}(stat.) +/- 0.02(syst.)$ ps. In addition, for the \Xi^-_b baryon we measure a mass of 5790.9 +/- 2.6(stat.) +/- 0.8(syst.) MeV/c^2 and a lifetime of 1.56^{+0.27}_{-0.25}(stat.) +/-0.02(syst.) ps. Under the assumption that the \Xi_b^- and \Omega_b^- are produced with similar kinematic distributions to the \Lambda^0_b baryon, we find sigma(Xi_b^-) B(Xi_b^- -> J/psi Xi^-)}/ sigma(Lambda^0_b) B(Lambda^0_b -> J/psi Lambda)} = 0.167^{+0.037}_{-0.025}(stat.) +/-0.012(syst.) and sigma(Omega_b^-) B(Omega_b^- -> J/psi Omega^-)/ sigma(Lambda^0_b) B(Lambda^0_b -> J/psi Lambda)} = 0.045^{+0.017}_{-0.012}(stat.) +/- 0.004(syst.) for baryons produced with transverse momentum in the range of 6-20 GeV/c.

Microbially induced separation of quartz from hematite using sulfate reducing bacteria

Cells and metabolic products of Desulfovibrio desulfuricans were successfully used to separate quartz from hematite through environmentally benign microbially induced flotation. Bacterial metabolic products such as extracellular proteins and polysaccharides were isolated from both unadapted and mineral-adapted bacterial metabolite and their basic characteristics were studied in order to get insight into the changes brought about on bioreagents during adaptation. Interaction between bacterial cells and metabolites with minerals like hematite and quartz brought about significant surface-chemical changes on both the minerals. Quartz was rendered more hydrophobic, while hematite became more hydrophilic after biotreatment.The predominance of bacterial polysaccharides on interacted hematite and of proteins on quartz was responsible for the above surface-chemical changes, as attested through adsorption studies. Surface-chemical changes were also observed on bacterial cells after adaptation to the above minerals. Selective separation of quartz from hematite was achieved through interaction with quartz-adapted bacterial cells and metabolite. Mineral-specific proteins secreted by quartz-adapted cells were responsible for conferment of hydrophobicity on quartz resulting in enhanced separation from hematite through flotation. (C) 2010 Elsevier B.V. All rights reserved.

An electron diffraction investigation of the molecular structure of trichloroacetonitrile

The molecular structure of trichloroacetonitrile has been studied by electron diffraction by the visual interpretation of sectored photographs. These parameters were obtained: C-N = 1.165 ± 0.025, C-C = 1.465 ± 0.025, C-Cl = 1.765 ± 0.01 A., and < CCCl = 109.5 ± 1°.

Crystallographic Evolution, Dielectric, and Piezoelectric Properties of Bi4Ti3O12:W/Cr Ceramics

W/Cr codoped Bi4Ti3O12 ceramics, Bi4Ti3-xWxO12+x+0.2 wt%Cr2O3 (BITWC, x=0-0.15), were prepared using a solid-state reaction method. The crystallographic evolution and phase analysis were distinctly determined focusing on the X-ray diffraction peak changes in (020)/(200) and (220)/(1115) diffraction planes, by which the lattice parameters, a, b, and c can be refined. The thermal variations of permittivity, dielectric loss (tan delta), impedance, and electrical conductivity properties were characterized. A decrease in the values of Curie temperature from 675 degrees to 640 degrees C and an increase in the values of the dielectric constant due to an increase of W6+/Cr3+ content were observed. The highest piezoelectric constant, d(33) of 22 pC/N, was achieved with the composition of Bi4Ti2.975W0.025O12.025+0.2 wt% Cr2O3. Also, this composition had a lower electrical conductivity than the other investigated compositions.

Information Technology in Construction – Domain Definition and Research Issues

This article discusses the scope of research on the application of information technology in construction (ITC). A model of the information and material activities which together constitute the construction process is presented, using the IDEF0 activity modelling methodology. Information technology is defined to include all kinds of technology used for the storage, transfer and manipulation of information, thus also including devices such as copying machines, faxes and mobile phones. Using the model the domain of ITC research is defined as the use of information technology to facilitate and re-engineer the information process component of construction. Developments during the last decades in IT use in construction is discussed against a background of a simplified model of generic information processing tasks. The scope of ITC is compared with the scopes of research in related areas such as design methodology, construction management and facilities management. Health care is proposed as an interesting alternative (to the often used car manufacturing industry), as an IT application domain to compare with. Some of the key areas of ITC research in recent years; expert systems, company IT strategies, and product modelling are shortly discussed. The article finishes with a short discussion of the problems of applying standard scientific methodology in ITC research, in particular in product model research.

Two-agent cooperative search using game models with endurance-time constraints

In this article, the problem of two Unmanned Aerial Vehicles (UAVs) cooperatively searching an unknown region is addressed. The search region is discretized into hexagonal cells and each cell is assumed to possess an uncertainty value. The UAVs have to cooperatively search these cells taking limited endurance, sensor and communication range constraints into account. Due to limited endurance, the UAVs need to return to the base station for refuelling and also need to select a base station when multiple base stations are present. This article proposes a route planning algorithm that takes endurance time constraints into account and uses game theoretical strategies to reduce the uncertainty. The route planning algorithm selects only those cells that ensure the agent will return to any one of the available bases. A set of paths are formed using these cells which the game theoretical strategies use to select a path that yields maximum uncertainty reduction. We explore non-cooperative Nash, cooperative and security strategies from game theory to enhance the search effectiveness. Monte-Carlo simulations are carried out which show the superiority of the game theoretical strategies over greedy strategy for different look ahead step length paths. Within the game theoretical strategies, non-cooperative Nash and cooperative strategy perform similarly in an ideal case, but Nash strategy performs better than the cooperative strategy when the perceived information is different. We also propose a heuristic based on partitioning of the search space into sectors to reduce computational overhead without performance degradation.

On superconducting Y-Ba-Cu-O films prepared by printing on lumina substrates

This Letter attempts to examine the impact of the chemical interaction of the alumina substrate on the Y-Ba-Cu-O film deposited on it.

Search for new transparent conductors: Effect of Ge doping on the conductivity of Ga2O3, In2O3 and Ga1.4In0.6O3

Only a small amount (<= 3.5 mol%) of Ge can be doped in Ga2O3, Ga1.4In0.6O3 and In2O3 by means of solid state reactions at 1400 degrees C. All these samples are optically transparent in the visible range, but Ge-doped Ga2O3 and Ga1.4In0.6O3 are insulating. Only Ge-doped In2O3 exhibits a significant decrease in resistivity, the resistivity decreasing further on thermal quenching and H-2 reduction.The resistivity of 2.7% Ge-doped In2O3 after H-2 reduction shows a metallic behavior, and a resistivity of similar to 1 m Omega cm at room temperature, comparable to that of Sn-doped In2O3. (C) 2010 Elsevier Ltd. All rights reserved.

Hormones andCuscuta development: interaction of cytokinin and indole-3-acetic acid in the growth and curvature of subapical stem segments

Cuscuta stem (vines) exhibits two modes of growth—longitudinal elongation forming free-hanging vines, or coiling growth to twine around the host. The elongation zone of free-hanging vine extended up to 160 mm from the stem apex and in vivo growth rate (during 8 h of growth) was maximal in the 20-to-40-mm region. While gibberellic acid (GA3) or fusicoccin (FC) could maintain (GA3) or enhance (FC) the growth rate of apical (10 or 25 mm) segments, indole-3-acetic acid (IAA) (10 mgrM) induced growth only in subapical (5–160 mm) segments. In vitro growth rate induced by IAA (10 mgrM) was similar to the in vivo growth rate up to 40 mm. Thereafter, up to 100 mm, IAA induced growth rate exceeded in vivo growth. p ]Subapical segments (sim13 mm) from 5- to 40-mm regions responded to a cytokinin (BA, Z, or iP) or to low IAA (0.1 mgrM) with curved growth, whereas the segments grew straight in the presence of high IAA (10 mgrM). Curvature (measured as the angle subtended at the center of the circle of which the segment formed an arc) induced by BA and low (0.1 mgrM) IAA was greater than either added separately. Besides, segments induced to curve in BA + low-IAA solution could be made to straighten out by transferring to a solution containing high IAA (10 mgrM) with or without BA. Thus in vivo patterns of straight and coiling growth could be mimicked reversibly in vitro by adjusting the relative concentrations of cytokinin and auxin; low auxin and cytokinin induced coiling growth, whereas high auxin and cytokinin induced straight growth. p ]Beyond 40 mm, BA had no growth-promoting or curvative-inducing effect.Cuscuta vine segments thus showed sequential sensitivity to applied hormones, the apical region (0–25 mm) to GA3, the subapical (5–40 mm) region to BA and IAA and the region beyond (40–160 mm) to IAA alone.

A lock-type cell for NMR studies at high hydrostatic pressures and low temperatures

Details of a simple and convenient high-pressure cell for continuous-wave, wide-line nuclear magnetic resonance investigation at high pressures and low temperatures are described. Experimental results obtained with the cell at 14*108 Pa and 77K for ammonium iodide are presented briefly.

Improved growth of GaN layers on ultra thin silicon nitride/Si (111) by RF-MBE

High-quality GaN epilayers were grown on Si (1 1 1) substrates by molecular beam epitaxy using a new growth process sequence which involved a substrate nitridation at low temperatures, annealing at high temperatures, followed by nitridation at high temperatures, deposition of a low-temperature buffer layer, and a high-temperature overgrowth. The material quality of the GaN films was also investigated as a function of nitridation time and temperature. Crystallinity and surface roughness of GaN was found to improve when the Si substrate was treated under the new growth process sequence. Micro-Raman and photoluminescence (PL) measurement results indicate that the GaN film grown by the new process sequence has less tensile stress and optically good. The surface and interface structures of an ultra thin silicon nitride film grown on the Si surface are investigated by core-level photoelectron spectroscopy and it clearly indicates that the quality of silicon nitride notably affects the properties of GaN growth. (C) 2010 Elsevier Ltd. All rights reserved.

Characterization, electrical percolation and magnetization studies of polystyrene/multiwall carbon nanotube composite films

Polystyrene/multiwall carbon nanotube composite films are prepared with loading up to 7 weight percent (wt%) of multiwall carbon nanotubes by solution processing and casting technique. In the formation of these composite films, iron filled carbon nanotubes with high aspect ratio (similar to 4000) were used. Scanning electron microscopy study shows that the nanotubes are uniformly dispersed within the polymer matrix. At high magnification, bending of carbon nanotubes is noticed which can be attributed to their elastic properties. The electrical conductivity measurements show that the percolation threshold is rather low at 0.21 wt%. Hysteresis loop measurements on the bulk multiwall carbon nanotube and composite samples are done at 10, 150 and 300 K and the coercivity values are found to be largest at all the temperatures, for 1 wt% composite sample. (C) 2010 Elsevier B.V. All rights reserved.

Heraproteiinivalmisteen vaikutus laihdutukseen ja laihdutustuloksen pysyvyyteen ylipainoisilla aikuisilla

Johdanto: Lihavuus on maailmalaajuisesti merkittävä kansanterveydellinen ja –taloudellinen ongelma. Lihavuuden ehkäisemiseksi ja epidemian leviämisen hillitsemiseksi on tärkeää tuntea lihavuuteen vaikuttavat tekijät. Yksittäisistä ruoka-aineista maidon käytön on havaittu monissa epidemiologisissa ja kokeellisissa tutkimuksissa olevan yhteydessä alhaisempaan painoon, ehkäisevän lihomista ja edistävän laihtumista. Maidon sisältämistä yhdisteistä kalsiumin vaikutuksia on tutkittu eniten. Myös heraproteiinin on esitetty olevan yksi mahdollinen painoon vaikuttava komponentti, ja näyttöä tästä on saatu eläinkokeista. Tavoitteet: Tutkimuksessa tavoitteena oli selvittää, vaikuttaako päivittäin nautittu heraproteiinia sisältävä välipalajuoma laihtumiseen tai saavutetun laihdutustuloksen pysyvyyteen ylipainoisilla aikuisilla. Aineisto ja menetelmät: Tutkimus toteutettiin osana Valio Oy:n OMPPU2-tutkimusta, joka oli satunnaistettu, lumekontrolloitu ja kaksoissokkoutettu kahden rinnakkaisen ryhmän tutkimus. Tutkimus alkoi rekrytoinneilla alkuvuodesta 2010, joissa tutkimukseen valittiin 105 ylipainoista (BMI 27–35), tervettä, 20–50-vuotiasta naista ja miestä. Tutkimushenkilöt satunnaistettiin tutkimus- ja verrokkiryhmiin, ja molemmat ryhmät nauttivat tutkimusvalmisteensa päivittäin hedelmätäysmehuun sekoitettuna (tutkimusryhmä heraproteiinijauheen ja verrokkiryhmä maltodekstriinijauheen). Tutkimus koostui kahdesta jaksosta: viiden kuukauden laihdutusjaksosta ja tätä seuranneesta kolmen kuukauden painonhallintajaksosta. Tutkimuskäynneillä tutkimuksen alussa, laihdutusjakson lopussa ja painonhallintajakson lopussa mitattiin tutkimushenkilöiden paino ja vyötärönympärys sekä määritettiin kehonkoostumus bioimpedanssilaitteella. Tutkimushenkilöiden ruoankäyttö ja ravinnonsaanti laskettiin samoissa aikapisteissä kerättyjen kolmen päivän ruokapäiväkirjojen perusteella. Tutkimushenkilöitä, joilla tutkimusvalmisteen käyttö oli alle 50 %, ei otettu huomioon tilastoanalyyseissä. Tilastollinen analyysi tehtiin käyttäen kahden riippumattoman otoksen t-testiä ja kaksisuuntaista parittaista t-testiä normaalijakautuneilla muuttujilla, ja Mann-Whitneyn U-testiä ja Wilcoxonin ttestiä ei-normaalijakautuneilla muuttujilla. Tutkimusvalmisteen ja painonmuutosten välinen korrelaatio laskettiin käyttäen Pearsonin korrelaatiokertoimia. Tulokset on ilmaistu keskiarvoina (keskihajonta). Tulokset: Molemmat ryhmät laihtuivat laihdutusjakson aikana. Heraproteiiniryhmässä painonpudotus oli 2,4 (3,8) kg (p=0,002) ja verrokkiryhmässä 3,4 (4,1) kg (p<0,001). Ryhmien välinen ero ei ollut merkitsevä. Rasvamassa väheni verrokkiryhmässä 2,4 (3,8) kg (p<0,001), mikä oli viiteellisesti enemmän (p=0,054) kuin heraproteiiniryhmässä 1,1 (3,1) kg (p=0,129). Rasvaprosentti ja viskeraalirasvan määrä pienenivät verrokkiryhmässä heraproteiiniryhmää enemmän (p<0,025). Vyötärönympärys pieneni heraproteiiniryhmässä 1,9 (3,0) cm (p=0,001) ja verrokkiryhmässä 3,8 (3,8) cm (p<0,001) ryhmien välisen eron ollessa merkitsevä (p=0,017). Maltodekstriinin käyttö korreloi käänteisesti painonmuutosten kanssa laihdutusjaksolla (r=-0,389, p=0,013). Painonhallintajaksolla painossa ei tapahtunut merkitseviä muutoksia kummassakaan ryhmässä. Heraproteiinin käytön ja painonmuutosten välisestä negatiivisesta korrelaatiosta oli viitteitä tällä jaksolla (r=-0,344, p=0,063). Kun tarkasteltiin koko tutkimuksen aikana tapahtuneita muutoksia (laihdutusjakson alusta painonhallintajakson loppuun), ei ryhmien välillä ollut merkitseviä eroja painon tai kehonkoostumuksen muutoksissa. Energiansaanti väheni molemmissa ryhmissä merkitsevästi laihdutusjakson aikana (p<0,01), mutta muutos ei eronnut ryhmien välillä. Ravintoaineista rasvan saanti väheni (p<0,001) ja C-vitamiinin saanti lisääntyi (p<0,001) molemmissa ryhmissä laihdutusjaksolla. Alkoholin saanti väheni verrokkiryhmässä (p=0,017). Proteiinin saanti lisääntyi heraproteiiniryhmässä merkitsevästi enemmän kuin verrokkiryhmässä (p=0,002). Painonhallintajaksolla energiansaanti ei muuttunut kummassakaan ryhmässä laihdutusjakson loppuun verrattuna. Fyysisessä aktiivisuudessa tutkimuksen aikana ei ollut eroa ryhmien välillä. Johtopäätökset: Heraproteiinin ei havaittu tehostavan laihdutusta maltodekstriiniin verrattuna tässä tutkimuksessa. Sen sijaan maltodekstriiniä nauttineessa ryhmässä rasvaprosentti ja erityisesti vatsan alueen rasva pienenivät heraproteiiniryhmää enemmän laihdutusjaksolla. Tulos oli lähes täysin vastakkainen tutkimushypoteesin kanssa, eikä vaikuttaisi selittyvän eroilla energiansaannissa tai fyysisessä aktiivisuudessa. Tämä tutkimus ei siis tue olettamusta, että heraproteiini osana laihdutusruokavaliota auttaisi laihdutuksessa. Painonhallintajaksolla heraproteiinin ja painonmuutosten välinen lähes merkitsevä käänteinen korrelaatio saattaa viitata heraproteiinin merkitykseen painonhallinnassa. Vapaasti elävien ihmisten kohdalla sekoittavia tekijöitä on kuitenkin vaikea vakioida, mikä vaikeuttaa johtopäätösten tekemistä.