Comments about birefringence dispersion, with group and phase birefringence measurements in polarization-maintaining fibers

A recent JEOS-RP publication proposed Comments about Dispersion of Light Waves, and we present here complementary comments for birefringence dispersion in polarization-maintaining (PM) fibers, and for its measurement techniques based on channeled spectrum analysis. We start by a study of early seminal papers, and we propose additional explanations to get a simpler understanding of the subject. A geometrical construction is described to relate phase birefringence to group birefringence, and it is applied to the measurement of several kinds of PM fibers using stress-induced photo-elasticity, or shape birefringence. These measurements confirm clearly that the difference between group birefringence and phase birefringence is limited to 15–20% in stress-induced PM fibers (bow-tie, panda, or tiger-eye), but that it can get up to a 3-fold factor with an elliptical-core (E-core) fiber. There are also surprising results with solid-core micro-structured PM fibers, that are based on shape birefringence, as E-core fibers

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Comments about birefringence dispersion, with group and phase birefringence measurements in polarization-maintaining fibers

A recent JEOS-RP publication proposed Comments about Dispersion of Light Waves , and we present here complementary comments for birefringence dispersion in polarization-maintaining (PM) fibers, and for its measurement techniques based on channeled spectrum analysis. We start by a study of early seminal papers, and we propose additional explanations to get a simpler understanding of the subject. A geometrical construction is described to relate phase birefringence to group birefringence, and it is applied to the measurement of several kinds of PM fibers using stress-induced photo-elasticity, or shape birefringence. These measurements confirm clearly that the difference between group birefringence and phase birefringence is limited to 15–20% in stress-induced PM fibers (bow-tie, panda, or tiger-eye), but that it can get up to a 3-fold factor with an elliptical-core (E-core) fiber. There are also surprising results with solid-core micro-structured PM fibers, that are based on shape birefringence, as E-core fibers

613 cases of splenic rupture without risk factors or previously diagnosed disease: a systematic review

Background Rupture of the spleen in the absence of trauma or previously diagnosed disease is largely ignored in the emergency literature and is often not documented as such in journals from other fields. We have conducted a systematic review of the literature to highlight the surprisingly frequent occurrence of this phenomenon and to document the diversity of diseases that can present in this fashion. Methods Systematic review of English and French language publications catalogued in Pubmed, Embase and CINAHL between 1950 and 2011. Results We found 613 cases of splenic rupture meeting the criteria above, 327 of which occurred as the presenting complaint of an underlying disease and 112 of which occurred following a medical procedure. Rupture appeared to occur spontaneously in histologically normal (but not necessarily normal size) spleens in 35 cases and after minor trauma in 23 cases. Medications were implicated in 47 cases, a splenic or adjacent anatomical abnormality in 31 cases and pregnancy or its complications in 38 cases. The most common associated diseases were infectious (n = 143), haematologic (n = 84) and non-haematologic neoplasms (n = 48). Amyloidosis (n = 24), internal trauma such as cough or vomiting (n = 17) and rheumatologic diseases (n = 10) are less frequently reported. Colonoscopy (n = 87) was the procedure reported most frequently as a cause of rupture. The anatomic abnormalities associated with rupture include splenic cysts (n = 6), infarction (n = 6) and hamartomata (n = 5). Medications associated with rupture include anticoagulants (n = 21), thrombolytics (n = 13) and recombinant G-CSF (n = 10). Other causes or associations reported very infrequently include other endoscopy, pulmonary, cardiac or abdominal surgery, hysterectomy, peliosis, empyema, remote pancreato-renal transplant, thrombosed splenic vein, hemangiomata, pancreatic pseudocysts, splenic artery aneurysm, cholesterol embolism, splenic granuloma, congenital diaphragmatic hernia, rib exostosis, pancreatitis, Gaucher's disease, Wilson's disease, pheochromocytoma, afibrinogenemia and ruptured ectopic pregnancy. Conclusions Emergency physicians should be attuned to the fact that rupture of the spleen can occur in the absence of major trauma or previously diagnosed splenic disease. The occurrence of such a rupture is likely to be the manifesting complaint of an underlying disease. Furthermore, colonoscopy should be more widely documented as a cause of splenic rupture

Discrimination à l’embauche des personnes d’origine supposée maghrébine : quels enseignements d’une grande étude par testing ?

Note IPP, n° 76, novembre 2021De nombreuses études montrent que les Français issus de l’immigration maghrébine se heurtent à des difficultés importantes sur le marché du travail, et ce dès la première étape de recrutement. Les résultats d’un testing récent et de grande ampleur le confirment. La discrimination à l’embauche selon l’origine supposée reste élevée et un élément majeur du marché du travail en France. En moyenne, à qualité comparable, les candidatures dont l’identité suggère une origine maghrébine ont 31,5 % de chances de moins d’être contactées par les recruteurs que celles portant un prénom et nom d’origine française. Si les discriminations liées à l’origine supposée sont fortes et persistantes, elles sont plus faibles, sans s’effacer, parmi les salariés les plus qualifiés. Ces résultats ne varient pas sensiblement entre les femmes et les hommes

Discrimination à l’embauche des personnes d’origine supposée maghrébine : quels enseignements d’une grande étude par testing ?

Note IPP, n° 76, novembre 2021De nombreuses études montrent que les Français issus de l’immigration maghrébine se heurtent à des difficultés importantes sur le marché du travail, et ce dès la première étape de recrutement. Les résultats d’un testing récent et de grande ampleur le confirment. La discrimination à l’embauche selon l’origine supposée reste élevée et un élément majeur du marché du travail en France. En moyenne, à qualité comparable, les candidatures dont l’identité suggère une origine maghrébine ont 31,5 % de chances de moins d’être contactées par les recruteurs que celles portant un prénom et nom d’origine française. Si les discriminations liées à l’origine supposée sont fortes et persistantes, elles sont plus faibles, sans s’effacer, parmi les salariés les plus qualifiés. Ces résultats ne varient pas sensiblement entre les femmes et les hommes

Discrimination in hiring people of supposedly North African origin: What lessons from a large-scale correspondence test?

IPP Policy Brief n°76This study is the result of a collaboration between the Direction de l’Animation de la Recherche, des Études et des Statistiques – Mission d’Animation de la Recherche (Dares-MAR), the Institut des Politiques Publiques (IPP) and the Inter Service Migrants – Centre d’Observation et de Recherche sur l’Urbain et ses Mutation (ISM CORUM). This study benefited from financial support provided by the Dares