Observation of sub-Poisson photon statistics in the cavity-QED microlaser

We have measured the second-order correlation function of the cavity-QED microlaser output and observed a transition from photon bunching to antibunching with increasing average number of intracavity atoms. The observed correlation times and the transition from super- to sub-Poisson photon statistics can be well described by gain-loss feedback or enhanced/reduced restoring action against fluctuations in photon number in the context of a quantum microlaser theory and a photon rate equation picture. However, the theory predicts a degree of antibunching several times larger than that observed, which may indicate the inadequacy of its treatment of atomic velocity distributions.Comment: 4 pages, 4 figure

A first principles investigation of cubic BaRuO3_3: A Hund's metal

A first-principles investigation of cubic-BaRuO$_3$, by combining density functional theory with dynamical mean-field theory and a hybridization expansion continuous time quantum Monte-Carlo solver, has been carried out. Non-magnetic calculations with appropriately chosen on-site Coulomb repulsion, $U$ and Hund's exchange, $J$, for single-particle dynamics and static susceptibility show that cubic-BaRuO$_3$ is in a spin-frozen state at temperatures above the ferromagnetic transition point. A strong red shift with increasing $J$ of the peak in the real frequency dynamical susceptibility indicates a dramatic suppression of the Fermi liquid coherence scale as compared to the bare parameters in cubic-BaRuO$_3$. The self-energy also shows clear deviation from Fermi liquid behaviour that manifests in the single-particle spectrum. Such a clean separation of energy scales in this system provides scope for an incoherent spin-frozen (SF) phase, that extends over a wide temperature range, to manifest in non-Fermi liquid behaviour and to be the precursor for the magnetically ordered ground state.Comment: 10 pages, 12 figures, 1 tabl

Is routine hepaticojejunostomy at the time of unplanned surgical bypass required in the era of self-expanding metal stents?

Background: Hepaticojejunostomy is routinely performed in patients when inoperable disease is found at planned pancreatoduodenectomy; however, in the presence of self-expanding metal stent (SEMS) hepaticojejunostomy may not be required. The aim of this study was to assess biliary complications and outcomes in patients with unresectable disease at time of planned pancreaticoduodenectomy stratified by the management of the biliary tract.Material and methods: Retrospective analysis of patients undergoing surgery in January 2010-December 2015. Complications were measured using the Clavien-Dindo scale.Results: Of 149 patients, 111 (75%) received gastrojejunostomy and hepaticojejunostomy (double bypass group) and 38 (26%) received a single bypass in the presence of SEMS (single bypass group). Post-operative non-biliary [7 (18%) vs 43 (38%), (p = 0.028)] and biliary [0% vs 12 (11%), (p = 0.037)] complications were lower in the single bypass group. Hospital readmissions were significantly higher in the double bypass group (p = 0.021). Overall survival and the time to start chemotherapy were equivalent (p = n.s.).Conclusions: Complications are more common following double bypass compared to single bypass with SEMS suggesting that gastric bypass is adequate surgical palliation in presence of SEMS. This study adds further evidence that preoperative SEMS should be used in preference to plastic stents for suspected periampullary malignancy

Performance Evaluation Of Composite Sandwich Structures With Additively Manufactured Aluminum Honeycomb Cores With Increased Bonding Surface Area

Modern aerostructures, including wings and fuselages, increasingly feature sandwich structures due to their high-energy absorption, low weight, and high flexural stiffness. The face sheet of these sandwich structures are typically thin composite laminates with interior honeycombs made of Nomex or aluminum. Standard cores are structurally efficient, but their design cannot be varied throughout the structure. With additive manufacturing (AM) technology, these core geometries can be altered to meet the design requirements that are not met in standard honeycomb cores. This study used a modified aluminum honeycomb core, with increased surface area on the top and bottom, as the core material in sandwich panels. The modified honeycomb core was produced through the laser powder bed fusion method. The behavior of the modified sandwich composite panels was evaluated through three-point bend, edgewise compression, and impact tests, and their performance was compared to that of a conventional honeycomb core sandwich panel. The three-point bend test results indicated that the sandwich structure\u27s ultimate shear strength improved by 12.6% with the modified honeycomb core. Additionally, the displacement at the failure of the structure increased by 11%. The edgewise compression tests showed that the ultimate edgewise compressive strength improved by 19.1% when using the modified core. The impact test results revealed that the peak force increased by 8% and the energy-absorbing capacity of the sandwich structure increased by 20% with the use of the modified honeycomb core

Creation of 3D Digital Anthropomorphic Phantoms which Model Actual Patient Non-rigid Body Motion as Determined from MRI and Position Tracking Studies of Volunteers

Background: Patient motion during emission imaging can create artifacts in the reconstructed emission distributions, which may mislead the diagnosis. For example, in myocardial-perfusion imaging, these artifacts can be mistaken for defects. Various software and hardware approaches have been developed to detect and compensate for motion. There are various ways of testing the effectiveness of motion correction methods applied in emission tomography, including the use of realistic digital anthropomorphic phantoms. Purpose: The purpose of this study was to create 3D digital anthropomorphic phantoms based on MRI data of volunteers undergoing a series of clinically relevant motions. These phantoms with combined position tracking were used to investigate both imaging-data-driven and motion tracking strategies to estimate and correct for patient motion. Methods: MRI scans were obtained of volunteers undergoing a series of clinically relevant movements. During the MRI, the motions were recorded by near-infra-red cameras tracking using external markers on the chest and abdomen. Individual-specific extended cardiac-torso (XCAT) phantoms were created fit to our volunteer MRI imaging data representing pre- and post-motion states. These XCAT phantoms were then used to generate activity and attenuation distributions. Monte Carlo methods will then be performed to simulate SPECT acquisitions, which will be used to evaluate various motion estimation and correction strategies. Results: Three volunteers were scanned in the MRI with concurrent external motion tracking. Each volunteer performed five separate motions including an axial slide, roll, shoulder twist, spine bend, and arm motion. These MRI scans were then manually digitalized into 3D anthropomorphic XCAT phantoms. Activity and attenuation distributions were created for each XCAT phantom, representing fifteen individual-specific motions. Conclusions: Our results will be combined with the external motion tracking data to determine if external motion tracking accurately reflects heart position in patients undergoing cardiac SPECT imaging. This data will also be used to evaluate other motion correction methods in the future

Pancreas exocrine replacement therapy is associated with increased survival following pancreatoduodenectomy for periampullary malignancy

Background: Although many patients undergoing pancreatoduodenectomy (PD) for cancer have pancreatic exocrine insufficiency, pancreatic enzyme replacement therapy (PERT) is not routinely used, and effects upon post-operative survival are unclear.Methods: This review of patients undergoing PD for periampullary malignancy sought to test for an association between PERT and overall survival, with post-hoc subgroup analysis performed after stratifying patients by the year of surgery, pancreatic duct width and tumour type.Results: Some 202/469 (43.1%) patients received PERT. After accounting for pathological variables and chemotherapy, PERT use was found to be independently associated with improved survival on multivariable analysis [HR 0.72 (95% CI: 0.52-0.99), p = 0.044] and on propensity matched analysis (p = 0.009). The effect of PERT upon improved survival was predominantly observed amongst patients with a dilated pancreatic duct (>= 3 mm).Discussion: PERT use was independently associated with improved survival following PD for cancer. The validity of this observation is supported by an effect largely confined to those patients with a dilated pancreatic duct. The nutritional status of patients undergoing PD for cancer needs further investigation and the effects of PERT require verification in further clinical studies

Transrectal drainage of a diverticular abscess using a pigtail catheter without radiological guidance: a case report

<p>Abstract</p> <p>Introduction</p> <p>Percutaneous or endocavitory drainage of a diverticular abscess under radiological guidance often enables one to perform a one-staged resection and anastomosis (without stoma formation) instead of a two-staged procedure. It reduces the significant postoperative morbidity and mortality associated with the conventional emergency surgical management. However, radiological guidance is not always available due to limited resources during out-of-hours.</p> <p>Case presentation</p> <p>A 78-year-old Caucasian woman underwent transrectal drainage of a diverticular abscess performed with a pigtail catheter without radiological guidance. Technical details of the procedure are described and alternative options discussed.</p> <p>Conclusion</p> <p>In carefully selected patients, per-rectal drainage using a pigtail catheter can be performed without radiological guidance and the procedure offers a simple and effective way of controlling sepsis.</p