Dichroic atomic vapor laser lock with multi-gigahertz stabilization range

A dichroic atomic vapor laser lock (DAVLL) system exploiting buffer-gas-filled millimeter-scale vapor cells is presented. This system offers similar stability as achievable with conventional DAVLL system using bulk vapor cells, but has several important advantages. In addition to its compactness, it may provide continuous stabilization in a multi-gigahertz range around the optical transition. This range may be controlled either by changing the temperature of the vapor or by application of a buffer gas under an appropriate pressure. In particular, we experimentally demonstrate the ability of the system to lock the laser frequency between two hyperfine components of the $^{85}$Rb ground state or as far as 16 GHz away from the closest optical transition.Comment: 11 pages, 7 figures. Published in Review of Scientific Instruments 201

Gatekeeping, fast and slow: an empirical study of referral errors in the emergency department

Using data from over 300,000 visits to an emergency department (ED), we study the accuracy of gatekeeping decisions - the choices that physicians make regarding patient discharge or admission to the hospital. In our study context, we focus specifically on the effectiveness of a second gatekeeping stage in the ED - a clinical decision unit (CDU). While only 9.9% of patients in our sample are routed through the CDU, we find that had the unit not been in place during the observation period, the rates of unnecessary hospitalization and wrongful patient discharge from the ED would have increased by 14.3% and 29.6%, respectively. We also find that the CDU is especially beneficial for patients with a high ex ante risk of experiencing unnecessary hospitalization, with the rate for the most high-risk patients reduced from 14.0% without the CDU to just 4.8% had all such patients been routed through the CDU. The appropriateness of referrals is therefore a key contributor to the CDU's effectiveness: We estimate that random allocation of patients in our study hospital to the CDU would have reduced the unit's effectiveness by more than half. Finally, we investigate a critical trade-off in designing a two-stage gatekeeping system: Resources must be split between the two stages, increasing congestion in the first stage when the second stage is enlarged. We demonstrate that in the study hospital, the combination of an ED and CDU performs better than a pooled system that combines the capacity of both stages to enlarge the ED but does not have a designated CDU. In fact, we estimate that in this specific case, reducing the size of the first-stage ED in order to expand CDU capacity from the current 9.9% of ED patients to 25% would further reduce unnecessary hospitalizations by up to 33%. We discuss the insights that these results provide as to the circumstances under which it may be advantageous to add a second stage to a gatekeeping system

Economies of scale and scope in hospitals: an empirical study of volume spillovers

General hospitals across the world are becoming larger (i.e. admitting more patients each year) and more complex (i.e. offering a wider range of services to patients with more diverse care needs). Prior work suggests that an increase in patient volume in a hospital service is associated with reduced costs per patient in that service. However, it is unclear how volume changes in one service affect the costs of the other services in the same hospital. This paper investigates such volume-cost spillover effects between elective and emergency admissions and across specialties, using condition-level panel data comprising all acute hospital trusts in England over a period of ten years. We provide evidence that increased elective volume at a hospital is associated with an increase in the cost of emergency care (a negative spillover). Furthermore, for emergency admissions, we find evidence that increased emergency activity in one specialty is associated with lower costs of emergency care in other specialties (a positive spillover). By contrast, we find no evidence of spillover effects across specialties for elective admissions. We discuss the implications of these findings for individual hospital growth strategies and for the regional organization of hospital systems

Predicting semantic labels of text regions in heterogeneous document images

Contains fulltext : 214639.pdf (publisher's version ) (Open Access)KONVENS 2019: 15th Conference on Natural Language Processing, Erlangen, Germany, October 9-11, 201

Low-Frequency Noise Characterization of Ultra-shallow Gate N-channel Junction Field Effect Transistors

A recently developed technique for ultra shallow pn junction formation has been applied for the fabrication of ring-gate n-channel junction field effect devices (JFET) devices. Several different geometries, gate formation parameters and channel doping profiles have been realized and characterized with respect to I-V and C-V characteristics both on wafer and after packaging. Low-frequency noise measurements have been performed on packaged devices by mean of a cross-correlation scheme. Data have been compared both with that of similar devices fabricated in a standard process and with simulations results. The devices show good DC performance, and the transconductance values achieved, with respect of the channel dimensions, are notably high. No G-R noise was detected, but the devices yielded a high flicker noise component. This phenomenon is shown to be neither correlated to the device area nor to incidental trapping levels at the junction interface. It is therefore assumed that perimeter effects are decisive for the enhancement of the 1/f spectrum

Las órdenes militares en la cruzada granadina de Alfonso el Benigno (1329-1334)

A la memoria de la Dra. Regina Sainz de la MazaEn este estudio se recupera la investigación las Órdenes militares catalanoaragonesas durante el siglo XIV. El interés del trabajo radica en el hecho de que en él se considera, de manera conjunta, la actuación en la cruzada de las cuatro Órdenes militares enclavadas en territorio catalanoaragonés, lo cual permite observar tanto su distinto grado de participación como la diferente actitud del monarca hacia cada una de ellas.Peer reviewe

Gatekeepers at work: an empirical analysis of a maternity unit

We use a detailed operational and clinical data set from a maternity hospital to investigate how workload affects decisions in gatekeeper-provider systems, where the servers act as gatekeepers to specialists but may also attempt to serve customers themselves, albeit with a probability of success that is decreasing in the complexity of the customers’ needs. We study the effect of workload during a service episode on gatekeepers’ service configuration decisions and the rate at which gatekeepers refer customers to a specialist. We find that gatekeeper-providers (midwives in our context) make substantial use of two levers to manage their workload (measured as patients per midwife): they ration resource-intensive discretionary services (epidural analgesia) for customers with noncomplex service needs (mothers with spontaneous onset of labor) and, at the same time, increase the rate of specialist referral (physician-led delivery) for customers with complex needs (mothers with pharmacologically induced labor). The workload effect in the study unit is surprisingly large and comparable in size to those for leading clinical risk factors: when workload increases from two standard deviations below to two standard deviations above the mean, noncomplex cases are 28.8% less likely to receive an epidural, leading to a cost reduction of 8.7%, while complex cases are 14.2% more likely to be referred for a physician-led delivery, leading to a cost increase of 2.6%. These observations are consistent with overtreatment at both high and low workload levels, albeit for different types of patients, and suggest that smoothing gatekeeper workload would reduce variability in customer service experience

Combining the regularization strategy and the SQP to solve MPCC - A MATLAB implementation

Mathematical Program with Complementarity Constraints (MPCC) plays a very important role in many fields such as engineering design, economic equilibrium, multilevel game, and mathematical programming theory itself. In theory its constraints fail to satisfy a standard constraint qualification such as the linear independence constraint qualification (LICQ) or the Mangasarian-Fromovitz constraint qualification (MFCQ) at any feasible point. As a result, the developed nonlinear programming theory may not be applied to MPCC class directly. Nowadays, a natural and popular approach is try to find some suitable approximations of an MPCC so that it can be solved by solving a sequence of nonlinear programs. This work aims to solve the MPCC using nonlinear programming techniques, namely the SQP and the regularization scheme. Some algorithms with two iterative processes, the inner and the external, were developed. A set of AMPL problems from MacMPEC database [7] were tested. The algorithms performance comparative analysis was carried out

Immunosurveillance of lung melanoma metastasis in EBI-3-deficient mice mediated by CD8+ T cells.

EBV-induced gene 3 (EBI-3) codes for a soluble type I receptor homologous to the p40 subunit of IL-12 that is expressed by APCs following activation. In this study, we assessed the role of EBI-3 in a model of lung melanoma metastasis. Intravenous injection of the B16-F10 cell line resulted in a significant reduction of lung tumor metastasis in EBI-3(-/-) recipient mice compared with wild-type mice. The immunological finding accompanying this effect was the expansion of a newly described cell subset called IFN-gamma producing killer dendritic cells associated with CD8(+) T cell responses in the lung of EBI-3(-/-) mice including IFN-gamma release and TNF-alpha-induced programmed tumor cell death. Depletion of CD8(+) T cells as well as targeting T-bet abrogated the protective effects of EBI-3 deficiency on lung melanoma metastases. Finally, adoptive transfer of EBI-3(-/-) CD8(+) T cells into tumor bearing wild-type mice inhibited lung metastasis in recipient mice. Taken together, these data demonstrate that targeting EBI-3 leads to a T-bet-mediated antitumor CD8(+) T cell responses in the lung