352 research outputs found
On-chip Phase Locked Loop (PLL) design for clock multiplier in CMOS Monolithic Active Pixel Sensors (MAPS)
In a detector system, clock distribution to sensors must be controlled at a level allowing proper synchronisation. In order to reach theses requirements for the HFT (Heavy Flavor Tracker) upgrade at STAR (Solenoidal Tracker at RHIC), we have proposed to distribute a low frequency clock at 10 MHz which will be multiplied to 160 MHz in each sensor by a PLL. A PLL has been designed for period jitter less than 20 ps rms, low power consumption and manufactured in a 0.35 μm CMOS process
Radiation Tolerance of CMOS Monolithic Active Pixel Sensors with Self-Biased Pixels
CMOS Monolithic Active Pixel Sensors (MAPS) are proposed as a technology for
various vertex detectors in nuclear and particle physics. We discuss the
mechanisms of ionizing radiation damage on MAPS hosting the the dead time free,
so-called self bias pixel. Moreover, we discuss radiation hardened sensor
designs which allow operating detectors after exposing them to irradiation
doses above 1 Mra
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Food fortification and biofortification as potential strategies for prevention of vitamin D deficiency
Hypovitaminosis D (vitamin D deficiency) is widespread throughout the world.
The cutaneous production of vitamin D through sunlight can be limited by
several factors (e.g. skin pigmentation, sunscreen usage and, increasingly, indoor
lifestyle). Thus, diet has become an important strategy to increase vitamin D
intake and status {blood 25-hydroxyvitamin D [25(OH)D]}. However, there are a
limited number of foods that naturally contain vitamin D, and concentrations
can vary significantly between and within species. The need for vitamin Dfortified
foods (including via direct fortification and biofortification) to support
the adequacy of vitamin D status is a corollary of several limitations to
synthesise vitamin D from sunlight. Ergocalciferol (vitamin D2) and
cholecalciferol (vitamin D3) can be found in some mushrooms and animalderived
foods, respectively. Evidence has shown vitamin D3 is more effective than
vitamin D2 at raising 25(OH)D blood concentrations. The vitamin D metabolite,
25(OH)D3, is present in animal-derived foods (e.g. meat, eggs and fish), and
several intervention trials have shown 25(OH)D3 to be more effective at raising
blood 25(OH)D concentrations than vitamin D3. In addition, 25(OH)D3
supplements may prove to be preferable to vitamin D3 for patients with certain
clinical conditions. However, there is limited evidence on the effects of 25(OH)
D3-fortified foods on human vitamin D status and health, both in the general
population and patients with certain conditions, and long-term randomised
controlled trials are needed in this area
Lifetime antipsychotic medication and cognitive performance in schizophrenia at age 43 years in a general population birth cohort
This naturalistic study analysed the association between cumulative lifetime antipsychotic dose and cognition in schizophrenia after an average of 16.5 years of illness. Sixty participants with schizophrenia and 191 controls from the Northern Finland Birth Cohort 1966 were assessed at age 43 years with a neurocognitive test battery. Cumulative lifetime antipsychotic dose-years were collected from medical records and interviews. The association between antipsychotic dose-years and a cognitive composite score based on principal component analysis was analysed using linear regression. Higher lifetime antipsychotic dose-years were significantly associated with poorer cognitive composite score, when adjusted for gender, onset age and lifetime hospital treatment days. The effects of typical and atypical antipsychotics did not differ. This is the first report of an association between cumulative lifetime antipsychotic dose and global cognition in midlife schizophrenia. Based on these data, higher lifetime antipsychotic dose-years may be associated with poorer cognitive performance at age 43 years. Potential biases related to the naturalistic design may partly explain the results; nonetheless, it is possible that large antipsychotic doses harm cognition in schizophrenia in the long-term.Peer reviewe
Long-term antipsychotic and benzodiazepine use. and brain volume changes in schizophrenia : The Northern Finland Birth Cohort 1966 study
High doses of antipsychotics have been associated with loss in cortical and total gray matter in schizophrenia. However, previous imaging studies have not taken benzodiazepine use into account, in spite of evidence suggesting adverse effects such as cognitive impairment and increased mortality. In this Northern Finland Birth Cohort 1966 study, 69 controls and 38 individuals with schizophrenia underwent brain MRI at the ages of 34 and 43 years. At baseline, the average illness duration was over 10 years. Brain structures were delineated using an automated volumetry system, volBrain, and medication data on cumulative antipsychotic and benzodiazepine doses were collected using medical records and interviews. We used linear regression with intracranial volume and sex as covariates; illness severity was also taken into account. Though both medication doses associated to volumetric changes in subcortical structures, after adjusting for each other and the average PANSS total score, higher scan-interval antipsychotic dose associated only to volume increase in lateral ventricles and higher benzodiazepine dose associated with volume decrease in the caudate nucleus. To our knowledge, there are no previous studies reporting associations between benzodiazepine dose and brain structural changes. Further studies should focus on how these observations correspond to cognition and functioning.Peer reviewe
A vertex detector for the International Linear Collider based on CMOS sensors
The physics programme at the International Linear Collider (ILC) calls for a vertex detector (VD) providing unprecedented flavour tagging performances, especially for c-quarks and τ leptons. This requirement makes a very granular, thin and multi-layer VD installed very close to the interaction region mandatory. Additional constraints, mainly on read-out speed and radiation tolerance, originate from the beam background, which governs the occupancy and the radiation level the detector should be able to cope with. CMOS sensors are being developed to fulfil these requirements. This report addresses the ILC requirements (highly related to beamstrahlung), the main advantages and features of CMOS sensors, the demonstrated performances and the specific aspects of a VD based on this technology. The status of the main R&D directions (radiation tolerance, thinning procedure and read-out speed) are also presented
CMOS pixel sensor development: a fast read-out architecture with integrated zero suppression
International audienceCMOS Monolithic Active Pixel Sensors (MAPS) have demonstrated their strong potential for tracking devices, particularly for flavour tagging. They are foreseen to equip several vertex detectors and beam telescopes. Most applications require high read-out speed, which imposes sensors to feature digital output with integrated zero suppression. The most recent development of MAPS at IPHC and IRFU addressing this issue will be reviewed. The design architecture, combining pixel array, column-level discriminators and zero suppression circuits, will be presented. Each pixel features a preamplifier and a correlated double sampling (CDS) micro-circuit reducing the temporal and fixed pattern noises. The sensor is fully programmable and can be monitored. It will equip experimental apparatus starting data taking in 2009/2010
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