4,705 research outputs found

    Tests and final integration of the ATLAS semiconductor tracker

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    The Silicon Tracker (SCT) is part of the Inner Detector at the ATLAS experiment at CERN. Its basic building blocks are 5 different types of silicon strip modules. In total more than 15000 p-on-n single-sided silicon strip sensors of an area of about 61 m2 were used to produce 4088 SCT modules. An overall module production yield of 92% could be achieved, where the silicon modules comply with the tight electrical, thermal and mechanical specifications. The macro-assembly of 2112 barrel modules to the four barrel support cylinders was successfully carried out. The nine disks of one endcap are fully populated with 988 modules, and for the second endcap more than 50% of the modules are already mounted. Test results operating complete barrels will be presented as well as a description of the test setup. The different integration steps of the SCT with the surrounding Transition Radiation Tracker (TRT) will be explained. The installation of SCT and TRT into the ATLAS pit will happen during 2006

    Kaj transformirati? Izobra┼żevanje odraslih, trajnostni razvoj in okoljska gibanja

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    This thematic issue of Studies in Adult Education and Learning comprises six thematic articles, whose authors reflect on the challenges of sustainable development, environmental and sustainability education, environmental movements, transformations, and examine the role of adult education in these areas from various theoretical perspectives and by applying diverse methodological approaches.V tokratni tematski ┼ítevilki Andrago┼íkih spoznanj, ki zajema ┼íest tematskih ─Źlankov, avtorice in avtorji razmi┼íljajo o izzivih trajnostnega razvoja, okoljskega in trajnostnega izobra┼żevanja, okoljskih gibanjih, transformaciji in izobra┼żevanju odraslih z vidika razli─Źnih teoretskih perspektiv in metodolo┼íkih pristopov

    New inhibitory pathways in CD8 T cell function

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    An adaptive immune response is initiated upon recognition of antigen presented on the surface of antigen-presenting cell (APC) by T cells. CD8 T cells primed in the liver by antigen-presenting liver sinusoidal endothelial cells (LSECs) develop into nonresponsive cells with a memory-phenotype. Liver-primed CD8 T cells are not terminally committed to this unique differentiation state but develop into effector cells upon infection. The adaptive immune response is balanced by co-stimulatory and co-inhibitory signals. LSEC-primed CD8 T cells require co-inhibitory PD-L1 signals delivered by LSECs to develop into a nonresponsive/memory state. In this study we investigated the relation between PD-L1/PD-1 signaling at early time-points and formation of an immune synapse, which may play a role in further development of effector function in T cells. Upon antigen-specific interaction of APC and T cell, an immunological synapse is formed at their interface that is required for signaling exchanged between these cells. In this study, we demonstrate that LSEC-CD8 T cell interaction results in multifocal immune synapse formation. Furthermore, although the development of nonresponsive state of liver-primed CD8 T cells requires co-inhibitory PD-L1/PD-1 signaling, the formation and phenotype of the immune synapse did not. Not only the absence of PD-L1 signaling, but also delivery of CD28 co-stimulatory signals can prevent differentiation of CD8 T cells into nonresponsiveness after priming by LSEC. Interestingly, we found that co-stimulation via CD28 was able to overcome this unique differentiation program when introduced between 0 and 36 hours of LSEC-CD8 T cell coculture, indicating that co-inhibitory PD-1 signaling is required to be integrated during this time to induce typical liver-primed non-responsive memory like T cells. Gene expression analysis identified the small GTPase ADP-ribosylation factor 4D (Arl4d) to be overexpressed in LSEC-primed CD8 T cells, compared to DC-primed CD8 T cells. More interestingly, Arl4d expression in CD8 T cells during LSEC-priming is dependent on PD-L1/PD-1 signaling. Similar to T cells activated in the presence of co-inhibitory PD-1 signaling, in the presence of Arl4d expression IL-2 production by CD8 T cells is attenuated in vitro and in vivo. In addition, Arl4d restricts effector CD8 T cell development and expansion on viral infection. Taken together, this study reveals a new as-yet undiscovered inhibitory function of Arl4d in modulating T cell immunity most likely via the regulation of IL-2 availability. Therefore, Arl4d might act downstream of co-inhibitory PD-1 signaling and thus play role in the regulation of CD8 T cell immunity

    CATALYST-ASSISTED CONVERSION OF PYROLYSIS BIO-OIL INTO FUELS

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    The aldol condensation of model compounds furfural and acetone on the selected base catalysts have been performed. The activity of MgO was compared with industrially produced hydrotalcite and the series laboratory prepared hydrotalcites. Si├ŚMAl2O4 hydrotalcites (M = Mg, Zn, Ni, Co, Cu, and Fe) were prepared by the sol-gel method at low calcination temperature of 300┬░C. The properties of the catalysts were evaluated by XRD and BET technique and they had a mesoporous structure. The aldol condensation was performed in the liquid phase preferably in N2 atmosphere, the temperature range of 25-140┬░C and at elevated pressure. The main condensation products were C8 FAc monomer and C13 F2Ac dimer. The first intermediate FAcol was readily dehydrated and higher temperatures favoured the reaction. The furfural (F) conversion into the C8 product (FAc) from 55.9 up to 94.5% with the selectivity 41.0- 79.5% was reached. In the comparative tests of MHT hydrotalcites performed at 140┬░ C, the best results were obtained in the case of Zn and Mg hydrotalcites despite their low specific surface. High selectivity to F2Ac was observed with Ni and Co hydrotalcites as catalysts with the specific surface area of 178 and 246 m2/g, respectively. As the key parameter for the high conversions the ratio catalyst/furfural close to 0.3 was notified

    U─Źinak ┼żivih stanica kvasca (Saccharomyces cerevisiae) na proizvodne rezultate pa┼íno dr┼żanih, mlije─Źnih ovaca tijekom kasne laktacije

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    A feeding trial was conducted in order to evaluate the influence of live yeast cells (Saccharomyces cerevisiae) on milk production and composition, and on blood parameters in late lactation. The experiment was performed on forty Croatian crossbred dairy sheep divided into a control group without live yeast cells (CD = control diet) and the experimental group with live yeast cells in the diet (YC = diet with Saccharomyces cerevisiae). The diet was based on pasture and concentrate containing corn (66.3%), soybean meal (18.7%), bran (6%) and alfalfa meal (4%). Supplementation with live yeast cells significantly increased the total milk yield in the 23rd week (P<0.5) and in the 27th week (P<0.5). Morning milk yield was also significantly increased in that period. All other values concerning milk yield did not differ significantly between treatment groups. The average amount of milk during the experimental period was higher in the YC group than in the CD group (604.60 ┬▒ 83.21 and 630.28 ┬▒ 92.34, for control and yeast-supplemented group, respectively) but without any significant difference (P>0.5). The chemical composition of the milk was not influenced by the treatments with the exception of milk fat that was significantly higher in YC group. Blood parameters were not affected by the treatment. We conclude that supplementation with live yeast cells, under the conditions of our experiment, had no statistically significant beneficial effects on the performance of dairy ewes during late lactation. High concentrate diet, the stage of lactation and high temperatures may have decreased the response to live yeast cells.Proveden je hranidbeni pokus kako bi se procijenio u─Źinak ┼żivih stanica kvasca (Saccharomyces cerevisiae) na proizvodnju i sastav mlijeka te krvne pokazatelje u kasnoj laktaciji. Pokus je proveden na 40 ovaca hrvatske oplemenjene mlije─Źne pasmine koje su bile podijeljene u kontrolnu skupinu bez ┼żivih stanica kvasca (CD = kontrolna hrana) i pokusnu sa ┼żivim stanicama kvasca u hrani (YC = hrana sa Saccharomyces cerevisiae). Obrok je zasnovan na pa┼íi i koncentratnom dodatku koji se sastojao od kukuruza (66,3%), sojine sa─Źme (18,7%), sto─Źnog bra┼ína (6%) i bra┼ína lucerne (4%). Dodatak ┼żivih stanica kvasca zna─Źajno je pove─çao dnevnu koli─Źinu mlijeka u 23. tjednu (P<0,5) i 27. tjednu (P<0,5). Jutarnja koli─Źina mlijeka tako─Ĺer je bila zna─Źajno vi┼ía u tom razdoblju. Sve ostale vrijednosti vezane uz koli─Źinu mlijeka nisu se zna─Źajno razlikovale. Prosje─Źna koli─Źina mlijeka tijekom pokusnog razdoblja bila je vi┼ía u YC skupini nego u CD skupini (604,60 ┬▒ 83,21 i 630,28 ┬▒ 92,34, za kontrolnu i pokusnu skupinu), ali razlika nije bila statisti─Źki zna─Źajna (P>0,5). Postupci nisu utjecali na kemijski sastav mlijeka s izuzetkom mlije─Źne masti koja je bila zna─Źajno vi┼ía u pokusnoj skupini. Krvni se pokazatelji nisu razlikovali izme─Ĺu skupina. Zaklju─Źili smo da, u uvjetima na┼íeg pokusa, dodavanje ┼żivih stanica kvasca nije imalo statisti─Źki zna─Źajan utjecaj na proizvodne rezultate mlije─Źnih ovaca tijekom kasne laktacije. U─Źinak je vjerojatno bio smanjen zbog ve─çe koli─Źine koncentrata u obroku, stadija laktacije i visokih temperatura

    Verification and validation of CFD simulations with full-scale ship speed/power trial data

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    Verification and validation of Computational Fluid Dynamics (CFD) simulations of a full-scale ship trial are presented in this study. Speed/power trials were carried out according to industry standards for three different power settings. Measured data was corrected for environmental effects to obtain ideal trial runs. Ship-scale unsteady RANS CFD simulations were conducted. Grid refinement sensitivity was evaluated for each power setting. Furthermore, time-step sensitivity was assessed for the selected grids. Finally, assumptions regarding symmetry condition and turbulence model were verified. Simulated results were in good agreement with the test data, thus illustrating the capabilities of numerical methods to determine ship performance at full scale
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