Fractionation of N isotopes occurs in many metabolic reactions which causes tissue proteins to become enriched in 15N while urea (urine) is depleted in 15N relative to the diet. We investigated 15N ...enrichment of whole plasma and its relationship with feed conversion efficiency (FCE) in growing beef heifers (n 84) offered 2 kg/d of concentrates with grass silage ad libitum. Heifers were on average 299 (sd 48·3) d old and weighed 311 (sd 48·8) kg. Plasma was obtained on day 79 (n 84) of the experiment and from a subset of animals (n 20) on four occasions between days 16 and 79. Silage DM intake (DMI) averaged 4·1 (sd 0·74) kg/d and concentrate DMI was 1·72 kg/d. Mean mid-test live weight was 333 (sd 47·6) kg, daily gain was 0·53 (sd 0·183) kg, FCE (g live-weight gain/g DMI) was 0·09 (sd 0·028) and residual feed intake (RFI) was 0 (sd 0·428). N isotopic fractionation (Δ15N; plasma δ15N − diet δ15N) averaged 3·58 ‰ on day 79 (n 84) and 3·90 ‰ for the subset of heifers. There was no relationship between Δ15N and RFI. Plasma δ15N and Δ15N were related to both FCE (negative) and animal weight (positive) for the whole population, and repeatable for the subset of animals over four time points. These relationships of Δ15N with FCE and animal weight are consistent with the anticipated negative relationship with N-use efficiency. There is potential to use Δ15N to provide rapid, low-cost estimates of FCE in cattle.
The experiment BESIII, running at the accelerator BEPCII in Beijing (P.R.C.), is going to be updated with the replacement of the Inner Drift Chamber with a Cylindrical triple-GEM Inner Tracker ...(CGEM-IT). In the R&D stage, two standalone C++ codes were implemented: GTS (Garfield-based Triple-GEM Simulator), for digitization and tuning of simulated data to the experimental ones, and GRAAL (GEM Reconstruction And Analysis Library), for the reconstruction and analysis of the experimental events collected in testbeams. GTS simulates the triple-GEM response to the particle passage, treating each stage separately: ionization, GEM properties, gas mixture, magnetic field and finally the induction of the signal on the anode. The necessary information was extracted by GARFIELD++ simulations, parametrized and used as input in GTS. This speeds up the simulation, since GTS performs only samplings instead of the full digitization chain. The simulated events were reconstructed with the same procedure used for experimental data and tuning factors were evaluated to obtain a satisfactory match. GRAAL is used in the analysis of the testbeam experimental data. It provides several levels of reconstruction: from the cluster formation, gathering contiguous firing strips, to the spatial position and the signal time reconstruciton. Two algorithms are used: the charge centroid and the micro-TPC, which exploit the charge deposition on the strips and the time information. Also a merging of the two algorithms is available to efficiently weight the two outcomes and obtain the best estimate of the spatial coordinate. Moreover, GRAAL performs tracking and alignment. Both codes are going to be made available also for other MPGDs simulation and reconstruction.
Triple-GEM detectors are a well known technology in high energy physics. In order to have a complete understanding of their behavior, in parallel with on beam testing, a Monte Carlo code has to be ...developed to simulate their response to the passage of particles. The software must take into account all the physical processes involved from the primary ionization up to the signal formation, e.g. the avalanche multiplication and the effect of the diffusion on the electrons. In the case of gas detectors, existing software such as Garfield already perform a very detailed simulation but are CPU time consuming. A description of a reliable but faster simulation is presented here: it uses a parametric description of the variables of interest obtained by suitable preliminary Garfield simulations and tuned to the test beam data. It can reproduce the real values of the charge measured by the strip, needed to reconstruct the position with the Charge Centroid method. In addition, particular attention was put to the simulation of the timing information, which permits to apply also the micro-Time Projection Chamber position reconstruction, for the first time on a triple-GEM. A comparison between simulation and experimental values of some sentinel variables in different conditions of magnetic field, high voltage settings and incident angle will be shown.
Abstract
Aria is a plant hosting a
$${350}\,\hbox {m}$$
350
m
cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., ...Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of
$${^{39}\hbox {Ar}}$$
39
Ar
in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed,
$${^{39}\hbox {Ar}}$$
39
Ar
is a
$$\beta $$
β
-emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.
Neutrinoless double beta decay (0vββ) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own ...anti-particles (Majorana particles). Presently, this physics case is one of the most important research "beyond Standard Model" and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0vββ decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract information on the 0vββ Nuclear Matrix Elements. In DCE reactions and ββ decay indeed the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute cross-sections can give crucial information on ββ matrix elements. In a wider view, the NUMEN international collaboration plans a major upgrade of the INFN-LNS facilities in the next years in order to increase the experimental production of nuclei of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest as candidates for 0vββ.
The maintenance of murine embryonic stem (ES) cell self-renewal is regulated by leukemia inhibitory factor (LIF)-dependent
activation of signal transducer and activator of transcription 3 (STAT3) and ...LIF-independent mechanisms including Nanog, BMP2/4,
and Wnt signaling. Here we demonstrate a previously undescribed role for phosphoinositide 3-kinases (PI3Ks) in regulation
of murine ES cell self-renewal. Treatment with the reversible PI3K inhibitor, LY294002, or more specific inhibition of class
I A PI3K via regulated expression of dominant negative Îp85, led to a reduction in the ability of LIF to maintain self-renewal,
with cells concomitantly adopting a differentiated morphology. Inhibition of PI3Ks reduced basal and LIF-stimulated phosphorylation
of PKB/Akt, GSK3α/β, and S6 proteins. Importantly, LY294002 and Îp85 expression had no effect on LIF-induced phosphorylation
of STAT3 at Tyr 705 , but did augment LIF-induced phosphorylation of ERKs in both short and long term incubations. Subsequently, we demonstrate
that inhibition of MAP-Erk kinases (MEKs) reverses the effects of PI3K inhibition on self-renewal in a time- and dose-dependent
manner, suggesting that the elevated ERK activity observed upon PI3K inhibition contributes to the functional response we
observe. Surprisingly, upon long term inhibition of PI3Ks we observed a reduction in phosphorylation of β-catenin, the target
of GSK-3 action in the canonical Wnt pathway, although no consistent alterations in cytosolic levels of β-catenin were observed,
indicating this pathway is not playing a major role downstream of PI3Ks. Our studies support a role for PI3Ks in regulation
of self-renewal and increase our understanding of the molecular signaling components involved in regulation of stem cell fate.
Micro Pattern Gas Detectors (MPGD) are the new frontier in gas trackers. Among this kind of devices, the Gas Electron Multiplier (GEM) chambers are widely used. The experimental signals acquired with ...the detector must obviously be reconstructed and analysed. In this contribution, a new offline software to perform reconstruction, alignment and analysis on the data collected with APV-25 and TIGER ASICs will be presented. GRAAL (Gem Reconstruction And Analysis Library) is able to measure the performance of a MPGD detector with a strip segmented anode (presently). The code is divided in three parts: reconstruction, where the hits are digitized and clusterized; tracking, where a procedure fits the points from the tracking system and uses that information to align the chamber with rotations and shifts; analysis, where the performance is evaluated (e.g. efficiency, spatial resolution,etc.). The user must set the geometry of the setup and then the program returns automatically the analysis results, taking care of different conditions of gas mixture, electric field, magnetic field, geometries, strip orientation, dead strip, misalignment and many others.
Objective proteomic analysis offers opportunities for hypothesis generation on molecular events associated with pathogenesis in stem cells. Relative quantification mass spectrometry was employed to ...identify pathways affected by Tel/PDGFRβ, an oncogene associated with myeloproliferative neoplasia (MPN). Its effects on over 1800 proteins were quantified with high confidence. Of those up-regulated by Tel/PDGFRβ several were involved in the interferon gamma (IFNγ) response. To validate these observations we employed embryonic and myeloid stem cells models which revealed Tel/PDGFRβ-induced STAT1 up-regulation and activation was responsible for modulating the interferon response. A STAT1 target highly up-regulated was ICSBP, a transcriptional regulator of myeloid and eosinophilic differentiation. ICSBP interacts with CBP/p300 and Ets transcription factors, to promote transcription of additional genes, including the Egr family, key regulators of myelopoiesis. These interferon responses were recapitulated using IFNγ stimulation of stem cells. Thus Tel/PDGFRβ induces aberrant IFN signaling and downstream targets, which may ultimately impact the hematopoietic transcriptional factor network to bias myelomonocytic differentiation in this MPN.
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