A new experimental procedure for characterizing quantum effects in small magnetic particle systems

A new experimental procedure is discussed, which aims at separating thermal from quantum behavior independently of the energy barrier distribution in small particle systems. Magnetization relaxation data measured between 60 mK and 5 K on a sample of nanoparticles is presented. The comparison between experimental data and numerical calculations shows a clear departure from thermal dynamics for our sample, which was not obvious without using the new procedure presented here.Comment: LaTeX source, 6 pages, 5 PostScript figure

Aspects et évaluation post-thérapeutiques des lésions du foie après traitement non chirurgical

The main non-surgical treatments for liver lesions include chemotherapy, targeted treatments, chemoembolization and radiofrequency ablation. The post-treatment imaging features are variable and depend on the initial appearance of the lesion, the type of treatment and the imaging modality. Evaluation of tumour response to treatment is important. RECIST criteria based on unidimensional lesion measurements may not always be appropriate. Other evaluation criteria (Choi for GIST, EASL for HCC or Chun criteria.) may be more relevant

Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 mas remain mostly unknown due to intrinsic observational limitations. [...] The Southern MAssive Stars at High angular resolution survey (SMASH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/SAM, respectively probing the separation ranges 1-45 and 30-250mas and brightness contrasts of Delta H < 4 and Delta H < 5. Taking advantage of NACO's field-of-view, we further uniformly searched for visual companions in an 8''-radius down to Delta H = 8. This paper describes the observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1mas to 8'' and presents the catalog of detections, including the first resolved measurements of over a dozen known long-period spectroscopic binaries. Excluding known runaway stars for which no companions are detected, 96 objects in our main sample (DEC < 0 deg; H<7.5) were observed both with PIONIER and NACO/SAM. The fraction of these stars with at least one resolved companion within 200mas is 0.53. Accounting for known but unresolved spectroscopic or eclipsing companions, the multiplicity fraction at separation < 8'' increases to f_m = 0.91 +/- 0.03. The fraction of luminosity class V stars that have a bound companion reaches 100% at 30mas while their average number of physically connected companions within 8'' is f_c = 2.2 +/- 0.3. This demonstrates that massive stars form nearly exclusively in multiple systems. Additionally, the nine non-thermal (NT) radio emitters observed by SMASH+ are all resolved [...]Comment: 57 pages, 20 figures, 7 tables; accepted for publication in ApJ

Physical occupational exposures and health expectancies in a French occupational cohort.

OBJECTIVES: To examine the relationships of strenuous and hazardous working conditions and rotating shifts that involve night working with life expectancy in good perceived health and life expectancy without chronic disease. METHODS: The sample contained male gas and electricity workers from the French GAZEL cohort (n=13 393). Six measures of physical working conditions were examined: Self-reports from 1989 and 1990 of ergonomic strain, physical danger, rotating shifts that involve night working and perceived physical strain; company records of workplace injuries and a job-exposure matrix of chemical exposures. Partial healthy life expectancies (age 50-75) relating to (1) self-rated health and (2) chronic health conditions, obtained from annual questionnaires (1989-2014) and company records, were estimated using multistate life tables. The analyses were adjusted for social class and occupational grade. RESULTS: Participants with physically strenuous jobs and who had experienced industrial injuries had shorter partial life expectancy. More physically demanding and dangerous work was associated with fewer years of life spent in good self-rated health and without chronic conditions, with the exception of shift work including nights, where the gradient was reversed. CONCLUSIONS: Strenuous and hazardous work may contribute to lost years of good health in later life, which has implications for individuals' quality of life as well as healthcare use and labour market participation

Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor. II. Concept validation with ZELDA on VLT/SPHERE

Warm or massive gas giant planets, brown dwarfs, and debris disks around nearby stars are now routinely observed by dedicated high-contrast imaging instruments on large, ground-based observatories. These facilities include extreme adaptive optics (ExAO) and state-of-the-art coronagraphy to achieve unprecedented sensitivities for exoplanet detection and spectral characterization. However, differential aberrations between the ExAO sensing path and the science path represent a critical limitation for the detection of giant planets with a contrast lower than a few $10^{-6}$ at very small separations (<0.3\as) from their host star. In our previous work, we proposed a wavefront sensor based on Zernike phase contrast methods to circumvent this issue and measure these quasi-static aberrations at a nanometric level. We present the design, manufacturing and testing of ZELDA, a prototype that was installed on VLT/SPHERE during its reintegration in Chile. Using the internal light source of the instrument, we performed measurements in the presence of Zernike or Fourier modes introduced with the deformable mirror. Our experimental and simulation results are consistent, confirming the ability of our sensor to measure small aberrations (<50 nm rms) with nanometric accuracy. We then corrected the long-lived non-common path aberrations in SPHERE based on ZELDA measurements. We estimated a contrast gain of 10 in the coronagraphic image at 0.2\as, reaching the raw contrast limit set by the coronagraph in the instrument. The simplicity of the design and its phase reconstruction algorithm makes ZELDA an excellent candidate for the on-line measurements of quasi-static aberrations during the observations. The implementation of a ZELDA-based sensing path on the current and future facilities (ELTs, future space missions) could ease the observation of the cold gaseous or massive rocky planets around nearby stars.Comment: 13 pages, 12 figures, A&A accepted on June 3rd, 2016. v2 after language editin

Benefit of the Vittel criteria to determine the need for whole body scanning in a severe trauma patient.

OBJECTIVE: To evaluate the use of the Vittel criteria in addition to a clinical examination to determine the need for a whole body scan (WBS) in a severe trauma patient. MATERIALS AND METHODS: Between December 2008 and November 2009, 339 severe trauma patients with at least one Vittel criterion were prospectively evaluated with a WBS. The following data were collected: the Vittel criteria present, circumstances of the accident, traumatic injury on the WBS, and irradiation. The original intent to prescribe a computed tomography (CT) scan (whole body or a targeted region), based solely on clinical signs, was specified. RESULTS: Injuries were diagnosed in 55.75% of the WBS (n=189). The most common Vittel criteria were "global assessment" (n=266), "thrown, run over" (n=116), and "ejected from vehicle" (n=94). The multivariate analysis used the following as independent criteria for predicting severe traumatic injury on the WBS: Glasgow score less than 13, penetrating trauma, and colloid resuscitation greater than 11. Based solely on clinical factors, 164 patients would not have had any scan or (only) a targeted scan. In that case, 15% of the severe injuries would have been missed. CONCLUSION: Using the Vittel criteria to determine the need for a WBS in a severe trauma patient makes it possible to find serious injuries not suspected on the clinical examination, but at the cost of an increased number of normal scans

Portosystemic collateral vessels in liver cirrhosis: a three-dimensional MDCT pictorial review

PURPOSE: Portosystemic collateral vessels (PSCV) are a consequence of the portal hypertension that occurs in chronic liver diseases. Their prognosis is strongly marked by the risk of digestive hemorrhage and hepatic encephalopathy. MATERIALS AND METHODS: CT was performed with a 16-MDCT scanner. Maximum intensity projection and volume rendering were systematically performed on a workstation to analyze PSCV. RESULTS: We describe the PSCV according to their drainage into either the superior or the inferior vena cava. In the superior vena cave group, we found gastric veins, gastric varices, esophageal, and para-esophageal varices. In the inferior vena cava group, the possible PSCV are numerous, with different sub groups: gastro and spleno renal shunts, paraumbilical and abdominal wall veins, retroperitoneal shunts, mesenteric varices, gallbladder varices, and omental collateral vessels. Regarding clinical consequences esophageal and gastric varices are most frequently involved in digestive bleeding; splenorenal shunts often lead to hepatic encephalopathy; the paraumbilical vein is an acceptable derivation pathway for natural decompression of the portal system. CONCLUSION: Knowledge of precise cartography of PSCV is essential to therapeutic decisions. MDCT is the best way to understand and describe the different types of PSCV

Non-monotonic field-dependence of the ZFC magnetization peak in some systems of magnetic nanoparticles

We have performed magnetic measurements on a diluted system of gamma-Fe2O3 nanoparticles (~7nm), and on a ferritin sample. In both cases, the ZFC-peak presents a non-monotonic field dependence, as has already been reported in some experiments,and discussed as a possible evidence of resonant tunneling. Within simple assumptions, we derive expressions for the magnetization obtained in the usual ZFC, FC, TRM procedures. We point out that the ZFC-peak position is extremely sensitive to the width of the particle size distribution, and give some numerical estimates of this effect. We propose to combine the FC magnetization with a modified TRM measurement, a procedure which allows a more direct access to the barrier distribution in a field. The typical barrier values which are obtained with this method show a monotonic decrease for increasing fields, as expected from the simple effect of anisotropy barrier lowering, in contrast with the ZFC results. From our measurements on gamma-Fe2O3 particles, we show that the width of the effective barrier distribution is slightly increasing with the field, an effect which is sufficient for causing the observed initial increase of the ZFC-peak temperatures.Comment: LaTeX file 19 pages, 9 postscript figures. To appear in Phys. Rev. B (tentative schedule: Dec.97

Sigmoid stricture associated with diverticular disease should be an indication for elective surgery with lymph node clearance

BACKGROUND: The literature concerning stricture secondary to diverticulitis is poor. Stricture in this setting should be an indication for surgery because (a) of the potential risk of cancer and (b) morbidity is not increased compared to other indications for colectomy. The goal of this report is to study the post-surgical morbidity and the quality of life in patients after sigmoidectomy for sigmoid stricture associated with diverticular disease. METHOD: This is a monocenter retrospective observational study including patients with a preoperative diagnosis of sigmoid stricture associated with diverticular disease undergoing operation between Jan 1, 2007 and Dec 31, 2013. The GastroIntestinal Quality of Life Index was used to assess patient satisfaction. RESULTS: Sixteen patients were included of which nine were female. Median age was 69.5 (46-84) and the median body mass index was 23.55kg/m(2) (17.2-28.4). Elective sigmoidectomy was performed in all 16 patients. Overall, complications occurred in five patients (31.2%) (4 minor complications and 1 major complication according to the Dindo and Clavien Classification); none resulted in death. Pathology identified two adenocarcinomas (12.5%). The mean GastroIntestinal Quality of Life Index was 122 (67-144) and 10/11 patients were satisfied with their surgical intervention. CONCLUSION: Sigmoid stricture prevents endoscopic exploration of the entire colon and thus it may prove difficult to rule out a malignancy. Surgery does not impair the quality of life since morbidity is similar to other indications for sigmoidectomy. For these reasons, we recommend that stricture associated with diverticular disease should be an indication for sigmoidectomy including lymph node clearance