Hubble Space Telescope Imaging of Lyman Alpha Emission at z=4.4

We present the highest redshift detections of resolved Lyman alpha emission, using Hubble Space Telescope/ACS F658N narrowband-imaging data taken in parallel with the Wide Field Camera 3 Early Release Science program in the GOODS CDF-S. We detect Lyman alpha emission from three spectroscopically confirmed z = 4.4 Lyman alpha emitting galaxies (LAEs), more than doubling the sample of LAEs with resolved Lyman alpha emission. Comparing the light distribution between the rest-frame ultraviolet continuum and narrowband images, we investigate the escape of Lyman alpha photons at high redshift. While our data do not support a positional offset between the Lyman alpha and rest-frame ultraviolet (UV) continuum emission, the half-light radii in two out of the three galaxies are significantly larger in Lyman alpha than in the rest-frame UV continuum. This result is confirmed when comparing object sizes in a stack of all objects in both bands. Additionally, the narrowband flux detected with HST is significantly less than observed in similar filters from the ground. These results together imply that the Lyman alpha emission is not strictly confined to its indigenous star-forming regions. Rather, the Lyman alpha emission is more extended, with the missing HST flux likely existing in a diffuse outer halo. This suggests that the radiative transfer of Lyman alpha photons in high-redshift LAEs is complicated, with the interstellar-medium geometry and/or outflows playing a significant role in galaxies at these redshifts.Comment: Submitted to the Astrophysical Journal. 11 pages, 10 figure

Human plague: An old scourge that needs new answers

Yersinia pestis, the bacterial causative agent of plague, remains an important threat to human health. Plague is a rodent-borne disease that has historically shown an outstanding ability to colonize and persist across different species, habitats, and environments while provoking sporadic cases, outbreaks, and deadly global epidemics among humans. Between September and November 2017, an outbreak of urban pneumonic plague was declared in Madagascar, which refocused the attention of the scientific community on this ancient human scourge. Given recent trends and plague’s resilience to control in the wild, its high fatality rate in humans without early treatment, and its capacity to disrupt social and healthcare systems, human plague should be considered as a neglected threat. A workshop was held in Paris in July 2018 to review current knowledge about plague and to identify the scientific research priorities to eradicate plague as a human threat. It was concluded that an urgent commitment is needed to develop and fund a strong research agenda aiming to fill the current knowledge gaps structured around 4 main axes: (i) an improved understanding of the ecological interactions among the reservoir, vector, pathogen, and environment; (ii) human and societal responses; (iii) improved diagnostic tools and case management; and (iv) vaccine development. These axes should be cross-cutting, translational, and focused on delivering context-specific strategies. Results of this research should feed a global control and prevention strategy within a “One Health” approach

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

An embedded probabilistic test instrument for built-in self-test methods

As circuits become increasingly complex and testing time continues to increase, it is becoming more and more important to use built-in self-test techniques to ensure that the circuit is working according to its data sheet specifications. This thesis presents an embedded probabilistic test instrument in an IBM 130 nm CMOS technology, which allows for quick and easy probabilistic test evaluation of the bit-error ratio of a device-under-test. The proposed probabilistic test instrument can be used to inject a multitude of test signals into a device under test including clock signals, AC signals, and signals with jitter modulated onto the clock edges.The device under test's performance is evaluated by extracting the output signal's edge locations. Using statistical methods, the probability distributions associated with the edge locations can be used to calculate the bit error-ratio that can be expected for the device under test. At the core of this work is the use of Sigma-Delta modulation techniques in combination with delay-locked loops to create a timing strobe that is finely and accurately controllable in order to be able to sample the eye-diagram of the device under test in various locations to extract the edge-location data. All of the timing strobes and stimulation signals as programmable in software in order to simplify the hardware design, as well as the work of the test engineer. The probabilistic test instrument was fabricated using IBM CMOS 130 nm technology and, in conjunction with a custom-designed PCB, the design was tested to ensure proper operation. The performance of the test instrument was evaluated by comparing the simulations to the measured results, as well as using external measurement devices to confirm on-chip measurements.De nos jours, les circuits deviennent de plus en plus complexes et le temps pour les tester continu d'augmenter. De ce fait, il devient de plus en plus primordial d'utiliser un mécanisme d’autotest qui sera intégré dans les circuits, afin que ceux-ci soient capables de s’assurer que leur fonctionnement est conforme à leurs fiches de données. Cette thèse introduit un instrument de probabilité qui utilise la technologie IBM CMOS 130 nm. Cet équipement permet une évaluation probabiliste en utilisant la fréquence d’erreurs binaires de l’appareil qui est sous test et ce, rapidement et facilement. L'instrument proposé ci-dessus peut être utilisée afin d’injecter une multitude de signaux tests dans l’appareil sous test. Ces signaux comprennent des signaux d'horloge, des signaux alternatifs, et des signaux gigues qui sont modulés avec les bords d'horloge.L’appareil testé pour sa performance, est ensuite évalué par extraction de l’emplacement du bord du signal de sortie. En utilisant des méthodes statistiques, les distributions de probabilités associées aux emplacements des bords du signal peuvent être utilisées afin de prédire la fréquence d'erreurs. Le cœur de ce travail est l'utilisation des techniques de modulation Sigma-Delta en combinaison avec une "delay-locked loop" pour créer un signal de synchronisation qui est précisément contrôlable afin d'être capable de prendre des échantillons dans différents endroits. L'instrument de test probabiliste a été fabriqué en utilisant la technologie IBM CMOS 130 nm en conjonction avec un circuit PCB fait sur mesure. La performance de l'instrument a été évaluée en comparant les résultats de mesure avec les simulations initiales ainsi qu’avec l'utilisation de dispositifs de mesure externes