3,371 research outputs found
Status of the 80Mbit/s Receiver for the CMS digital optical link
The first prototype of the 80Mbit/s optical receiver ASIC for the CMS digital optical link has been manufactured in a 0.25µm commercial CMOS process. The circuit design has been made using radiation tolerant layout techniques. Its performance satisfies the low power, wide dynamic range, sensitivity and speed specifications. The radiation hardness of the receiver has been verified irradiating the diode with 6 MeV neutrons (up to 6.5·1014 n/cm2) and the receiver circuit with 10KeV X-rays (up to 20 Mrad). A second prototype has been submitted for fabrication in the same commercial CMOS process. I
Optical links for the CMS tracker
The development phase of the optical data transfer system for the CMS tracker is nearing completion. This paper focuses on three types of validation tests carried out by CERN on Commercial-Off-The-Shelf electro-optic devices: functionality tests, environmental tests and reliability tests. The project status and the preparation for production are also reviewed. 1
Disrupted Glutamate Signaling in Drosophila Generates Locomotor Rhythms in Constant Light
We have used the Cambridge Protein Trap resource (CPTI) to screen for flies whose
locomotor rhythms are rhythmic in constant light (LL) as a means of identifying circadian
photoreception genes. From the screen of ∼150 CPTI lines, we obtained seven
hits, two of which targeted the glutamate pathway, Got1 (Glutamate oxaloacetate
transaminase 1) and Gs2 (Glutamine synthetase 2). We focused on these by employing
available mutants and observed that variants of these genes also showed high
levels of LL rhythmicity compared with controls. It was also clear that the genetic
background was important with a strong interaction observed with the common and
naturally occurring timeless (tim) polymorphisms, ls-tim and s-tim. The less circadian
photosensitive ls-tim allele generated high levels of LL rhythmicity in combination with
Got1 or Gs2, even though ls-tim and s-tim alleles do not, by themselves, generate the
LL phenotype. The use of dsRNAi for both genes as well as for Gad (Glutamic acid
decarboxylase) and the metabotropic glutamate receptor DmGluRA driven by clock
gene promoters also revealed high levels of LL rhythmicity compared to controls. It
is clear that the glutamate pathway is heavily implicated in circadian photoreception.
TIM levels in Got1 and Gs2 mutants cycled and were more abundant than in controls
under LL. Got1 but not Gs2 mutants showed diminished phase shifts to 10 min light
pulses. Neurogenetic dissection of the LL rhythmic phenotype using the gal4/gal80 UAS
bipartite system suggested that the more dorsal CRY-negative clock neurons, DNs and
LNds were responsible for the LL phenotype. Immunocytochemistry using the CPTI YFP
tagged insertions for the two genes revealed that the DN1s but not the DN2 and DN3s
expressed Got1 and Gs2, but expression was also observed in the lateral neurons, the
LNds and s-LNvs. Expression of both genes was also found in neuroglia. However,
downregulation of glial Gs2 and Got1 using repo-gal4 did not generate high levels
of LL rhythmicity, so it is unlikely that this phenotype is mediated by glial expression.
Our results suggest a model whereby the DN1s and possibly CRY-negative LNds use
glutamate signaling to supress the pacemaker s-LNvs in LL
Genomic selection for productive traits in biparental cassava breeding populations.
Cassava improvement using traditional breeding strategies is slow due to the species? long breeding cycle. However, the use of genomic selection can lead to a shorter breeding cycle. This study aimed to estimate genetic parameters for productive traits based on pedigree (pedigree and phenotypic information) and genomic (markers and phenotypic information) analyses using biparental crosses at different stages of selection. A total of 290 clones were genotyped and phenotyped for fresh root yield (FRY), dry matter content (DMC), dry yield (DY), fresh shoot yield (FSY) and harvest index (HI). The clones were evaluated in clonal evaluation trials (CET), preliminary yield trials (PYT), advanced yield trials (AYT) and uniform yield trials (UYT), from 2013 to 2018 in ten locations. The breeding stages were analyzed as follows: one stage (CET), two stages (CET and PYT), three stages (CET, PYT and AYT) and four stages (CET, PYT, AYT and UYT). The genomic predictions were analyzed via k-fold cross-validation based on the genomic best linear unbiased prediction (GBLUP) considering a model with genetic additive effects and genotype × location interactions. Genomic and pedigree accuracies were moderate to high (0.56?0.72 and 0.62?0.78, respectively) for important starch-related traits such as DY and FRY; when considering one breeding stage (CET) with the aim of early selection, the genomic accuracies ranged from 0.60 (DMC) to 0.71 (HI). Moreover, the correlations between the genomic estimation breeding values of one-stage genomic analysis and the estimated breeding values of the four-stage (full data set) pedigree analysis were high for all traits as well as for a selection index including all traits. The results indicate great possibilities for genomic selection in cassava, especially for selection early in the breeding cycle (saving time and effort)
Comparing seed production and regeneration of Carapa guianensis (Aublet.) in two forest types in Acre, Brazil from 2004 to 2007.
Carapa guianensis is a tropical tree valuable for its seed oil and timber. This study compared Carapa seed production and regeneration density in two forest types: upland and occasionally inundated
THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation
We report on the results of an extensive R&D program aimed at the evaluation
of Thick-Gas Electron Multipliers (THGEM) as potential active elements for
Digital Hadron Calorimetry (DHCAL). Results are presented on efficiency, pad
multiplicity and discharge probability of a 10x10 cm2 prototype detector with 1
cm2 readout pads. The detector is comprised of single- or double-THGEM
multipliers coupled to the pad electrode either directly or via a resistive
anode. Investigations employing standard discrete electronics and the KPiX
readout system have been carried out both under laboratory conditions and with
muons and pions at the CERN RD51 test beam. For detectors having a
charge-induction gap, it has been shown that even a ~6 mm thick single-THGEM
detector reached detection efficiencies above 95%, with pad-hit multiplicity of
1.1-1.2 per event; discharge probabilities were of the order of 1e-6 - 1e-5
sparks/trigger, depending on the detector structure and gain. Preliminary beam
tests with a WELL hole-structure, closed by a resistive anode, yielded
discharge probabilities of <2e-6 for an efficiency of ~95%. Methods are
presented to reduce charge-spread and pad multiplicity with resistive anodes.
The new method showed good prospects for further evaluation of very thin
THGEM-based detectors as potential active elements for DHCAL, with competitive
performances, simplicity and robustness. Further developments are in course.Comment: 15 pages, 11 figures, MPGD2011 conference proceedin
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