The electronic response of a telescope under direct illumination by a point-like light source is based on photon counting. With the data obtained using the SNDICE light source and the Megacam camera ...on the CFHT telescope, we show that the ultimate precision is only limited by the photon statistical fluctuation, which is below 1 ppm. A key feature of the analysis is the incorporation of diffuse light that interfers with specularly reflected light in the transmission model to explain the observed diffraction patterns. The effect of diffuse light, usually hidden conveniently in the Strehl ratio for an object at infinity, is characterized with a precision of 10 ppm. In particular, the spatial frequency representation provides some strong physical constraints and a practical monitoring of the roughness of various optical surfaces.
Summary
Reason for performing study: The development of clinical illness in foals is usually predetermined by perinatal history, management or stressful environmental conditions.
Objectives: To ...determine potential risk factors for an increased incidence of infectious diseases during the first 30 days post partum.
Methods: The population consisted of Thoroughbred foals born on stud farms in the Newmarket (UK) area in 2005 (n = 1031). They were followed for their first 30 days. Factors suspected to influence the incidence of infectious neonatal diseases were examined in a logistic regression approach for each of the 3 outcomes (total infectious diseases, systemic disease with diarrhoea and total infectious diseases excluding diarrhoea). All 28 factors were either foal or mare or stud farm related.
Results: Several significant risk factors for a higher disease incidence, such as birth complications, colostrum intake by stomach tube and leucocytosis 12–48 h post partum were identified. The factor ‘boarding stud’ seemed to be protective against disease.
Conclusion: Some factors, such as the mare's time at stud before foaling, the mare's rotavirus vaccination schedule and fibrinogen‐values that empirically had been linked to the outcome previously were not confirmed as relevant. This included the reported useful prophylactic treatment with antimicrobial drugs.
Potential relevance: Factors to be considered when evaluating newborn foals include: stud management, the birth process, route of colostrum intake, white and red blood cells, and the date of birth. These may help to detect foals at risk to develop an infection so that targeted prophylactic measures can be initiated.
Abstract Early pregnancy loss occurs in 6–10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of ...viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14–65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in AmnioChrome™ Plus. Genomic DNA of a suitable quality for molecular assays was also isolated from 29/30 of these cases. This method will enable future investigations determining pathologies causing EPL.
Cross sections for elastic and proton-dissociative photoproduction of
J
/
ψ
mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at
ep
...centre-of-mass energies
and
, corresponding to integrated luminosities of
and
, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25<
W
γp
<110 GeV. Differential cross sections d
σ
/d
t
, where
t
is the squared four-momentum transfer at the proton vertex, are measured in the range |
t
|<1.2 GeV
2
for the elastic process and |
t
|<8 GeV
2
for proton dissociation. The results are compared to other measurements. The
W
γp
and
t
-dependences are parametrised using phenomenological fits.
Measurements of open charm production cross sections in deep-inelastic
ep
scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections
for charm production are obtained ...in the kinematic range of photon virtuality 2.5≤
Q
2
≤2000 GeV
2
and Bjorken scaling variable 3⋅10
−5
≤
x
≤5⋅10
−2
. The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for
W
±
and
Z
production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.
Recent progresses of electronics, essentially due to its miniaturization, are opening new fields that were just dreamed of, notably in astronomy. At start in paragraph 3, we introduce the time ...variation of images expressing the dual nature of the optical signal (ZO) and we expose several useful applications where the optical signal variations are not faster than CCD. However we prefered to initiate the article with a deeper question posed inadvertently in paragraph 2: what causes the rapid, well timed and regular variation of the signals induced in our test setup, which we see in Fig. 1. The answer proposed are two causes: one is a light photon acting indirectly through the induction of a large number of secondary electrons (paragraph 2), the other are the RF photons (subliminal, but acting directly) as detailed in paragraph 4. For both light and RF, using a sum of induced currents instead of a single photon quadri-vector transform the case.
The H1 lead/scintillating-fibre calorimeter Appuhn, R.-D.; Arndt, C.; Barrelet, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1997, Letnik:
386, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The backward region of the H1 detector has been upgraded in order to provide improved measurement of the scattered electron in deep inelastic scattering events. The centerpiece of the upgrade is a ...high-resolution lead/scintillating-fibre calorimeter. The main design goals of the calorimeter are: good coverage of the region close to the beam pipe, high angular resolution and energy resolution of better than 2% for 30 GeV electrons. The calorimeter should be capable of providing coarse hadronic energy measurement and precise time information to suppress out-of-time background events at the first trigger level. It must be compact due to space restrictions. These requirements were fulfilled by constructing two separate calorimeter sections. The inner electromagnetic section is made of 0.5 mm scintillating plastic fibres embedded in a lead matrix. Its lead-to-fibre ratio is 2.3:1 by volume. The outer hadronic section consists of 1.0 mm diameter fibres with a lead-to-fibre ratio of 3.4:1. The mechanical construction of the new calorimeter and its assembly in the H1 detector are described.
Direct illumination LED calibration for telescope photometry Barrelet, E.; Juramy, C.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2008, Letnik:
585, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A calibration method for telescope photometry, based on the direct illumination of a telescope with a calibrated light source regrouping multiple LEDs, is proposed. Its purpose is to calibrate the ...instrument response. The main emphasis of the proposed method is the traceability of the calibration process and a continuous monitoring of the instrument in order to maintain a 0.2% accuracy over a period of years. Its specificity is to map finely the response of the telescope and its camera as a function of all light ray parameters. This feature is essential to implement a computer model of the instrument representing the variation of the overall light collection efficiency of each pixel for various filter configurations. We report on hardware developments done for SNDICE, the first application of this direct illumination calibration system which will be installed in Canada France Hawaii telescope (CFHT) for its leading supernova experiment (SNLS).
Aims. We describe the design, operation, and first results of a photometric calibration project, called DICE (Direct Illumination Calibration Experiment), aiming at achieving precise instrumental ...calibration of optical telescopes. The heart of DICE is an illumination device composed of 24 narrow-spectrum, high-intensity, light-emitting diodes (LED) chosen to cover the ultraviolet-to-near-infrared spectral range. It implements a point-like source placed at a finite distance from the telescope entrance pupil, yielding a flat field illumination that covers the entire field of view of the imager. The purpose of this system is to perform a lightweight routine monitoring of the imager passbands with a precision better than 5 per-mil on the relative passband normalisations and about 3 Å on the filter cutoff positions. Methods. Prior to installation, the light source is calibrated on a spectrophotometric bench. As our fundamental metrology standard, we use a photodiode calibrated at the National Institute of Standards and Technology (NIST). The radiant intensity of each beam is mapped, and spectra are measured for each LED. All measurements are conducted at temperatures ranging from 0 °C to 25 °C in order to study the temperature dependence of the system. The photometric and spectroscopic measurements are combined into a model that predicts the spectral intensity of the source as a function of temperature. Results. We find that the calibration beams are stable at the 10-4 level – after taking the slight temperature dependence of the LED emission properties into account. We show that the spectral intensity of the source can be characterised with a precision of 3 Å in wavelength, depending on how accurately we are able to calibrate the wavelength response of the mononochromator. In flux, we reach an accuracy of about 0.2 − 0.5% depending on how we understand the off-diagonal terms of the error budget affecting the calibration of the NIST photodiode. We describe how with a routine ≲ 60-mn calibration program, the apparatus is able to constrain the imager passbands at the targeted precision levels.
Summary
Reasons for performing study: Neonatal diseases have been grouped and analysed but up‐to‐date statistically significant information about the incidence and prevalence of diseases in foals is ...limited. Since the 1950s it has been a common management practice to administer a 3 day course of antimicrobial drugs to neonatal foals. This was shown to significantly reduce the incidence of infections (Platt 1977). Since then management practices have improved and it is widely believed that prophylactic antimicrobial drugs are no longer necessary in foal rearing.
Objectives: To determine the 30 day incidences or prevalences (depending on case definition) of various diseases and conditions in the neonatal foal and ascertain the influence of a prophylactic 3 day treatment on the frequency of infections.
Methods: The population consisted of Thoroughbred foals born on stud farms in the Newmarket (UK) area in 2005 (n = 1031). Depending on the stud farm's practice in the use of prophylactic antimicrobial drugs, 2 groups of newborn foals (treated and untreated) were identified and followed for 30 days.
Results: The 30 day incidences of infectious diseases under study were between 0.2% (osteomyelitis) and 5.85% (systemic disease with diarrhoea). The overall incidence for ‘total infectious diseases’ was 8.27%. The most commonly observed noninfectious condition was limb deformities (12.11% of all foals). There was no significant difference in the incidence of infectious diseases between the 2 groups.
Conclusion: Infectious diseases are still an important problem in neonatal foals requiring further investigation as to which factors other than antimicrobial prophylaxis are relevant for disease prevention.
Potential relevance: The results provide an up‐to‐date overview about the frequencies of various neonatal foal diseases. They do not support the traditional prophylactic use of antimicrobials to prevent infectious diseases in healthy newborn foals. However, it should be noted that this study was not a randomised controlled trial and therefore does not provide the strongest possible evidence for this conclusion.
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