Designing Minimum Cost Nonblocking Communication Networks

This paper addresses the problem of topological design of ATM (and similar) communication networks. We formulate the problem from a worst-case point of view, seeking network desings that, subject to specified traffic constraints, are nonblocking for point-to-point and multicast virtual circuits. Within this model we give various conditions under which star networks are optimal or near-optimal. These conditions are approximately satisfied in many common situations making the results of practical significance. An important consequence of these results is that, where they apply, there is no added cost for nonblocking multicast communication, relative to networks that are nonblocking for point-to-point traffic only

Laparoscopic Cholecystectomy in the Cirrhotic: Review of Literature on Indications and Technique

Cholelithiasis is twice more common in patients suffering from liver cirrhosis compared to overall population and in those patients, acute cholecystitis occurs significantly more often. Our goal was to review the literature and to overview the indications, contra-indications, and alternatives in the cirrhotic with biliary stones. We conducted a systematic review of the literature using the key words "Cirrhosis", "cholecystectomy", "laparoscopy"and "indications". Selected articles were reviewed for information specific to indications, contra-indications, and alternatives to laparoscopic cholecystectomy in cirrhotics. Results showed that laparoscopic cholecystectomy might offer several advantages in cirrhotic population, however cholecystectomy can be challenging: specific indications and alternatives to surgery must be discussed case by case. Laparoscopic cholecystectomy can be performed safely in selected patients with cirrhosis; special precautions are warranted regarding pneumoperitoneum pressure, trocar placement and increased safety with Indocyanine-green (ICG) fluorescence cholangiography. Nevertheless, in high-risk cirrhotic patients (Child C) and/or in common bile duct lithiasis endoscopic and non-surgical conservative treatments are preferable

Healthcare Stereotype Threat in Older Adults in the Health and Retirement Study

Introduction Healthcare stereotype threat is the threat of being personally reduced to group stereotypes that commonly operate within the healthcare domain, including stereotypes regarding unhealthy lifestyles and inferior intelligence. The objective of this study was to assess the extent to which people fear being judged in healthcare contexts on several characteristics, including race/ethnicity and age, and to test predictions that experience of such threats would be connected with poorer health and negative perceptions of health care. Methods Data were collected as part of the 2012 Health and Retirement Study (HRS). A module on healthcare stereotype threat, designed by the research team, was administered to a random subset (n=2,048 of the total 20,555) of HRS participants. The final sample for the present healthcare stereotype threat experiment consists of 1,479 individuals. Logistic regression was used to test whether healthcare stereotype threat was associated with self-rated health, reported hypertension, and depressive symptoms, as well as with healthcare-related outcomes, including physician distrust, dissatisfaction with health care, and preventative care use. Results Seventeen percent of respondents reported healthcare stereotype threat with respect to one or more aspects of their identities. As predicted, healthcare stereotype threat was associated with higher physician distrust and dissatisfaction with health care, poorer mental and physical health (i.e., self-rated health, hypertension, and depressive symptoms), and lower odds of receiving the influenza vaccine. Conclusions The first of its kind, this study demonstrates that people can experience healthcare stereotype threat on the basis of various stigmatized aspects of social identity, and that these experiences can be linked with larger health and healthcare-related outcomes, thereby contributing to disparities among minority groups

LA-ICP-MS/MS improves limits of detection in elemental bioimaging of gadolinium deposition originating from MRI contrast agents in skin and brain tissues

© 2018 Elsevier GmbH A novel analytical method to detect the retention of gadolinium from contrast agents for magnetic resonance imaging (MRI) in tissue samples of patients is presented. It is based on laser ablation - inductively coupled plasma - triple quadrupole - mass spectrometry (LA-ICP-MS/MS). Both Gd and P were monitored with a mass shift of +16, corresponding to mono-oxygenated species, as well as Zn, Ca, and Fe on-mass. This method resulted in a significantly reduced background and improved limits of detection not only for phosphorus, but also for gadolinium. These improvements were essential to perform elemental bioimaging with improved resolution of 5 μm x 5 μm, allowing the detection of small Gd deposits in fibrotic skin and brain tumour tissue with diameters of approximately 50 μm. Detailed analyses of these regions revealed that most Gd was accompanied with P and Ca, indicating co-precipitation

Manipulation of two-photon fluorescence spectra of chromophore aggregates with entangled photons: A simulation study

The non-classical spectral and temporal features of entangled photons offer new possibilities to investigate the interactions of excitons in photosynthetic complexes, and to target the excitation of specific states. Simulations of fluorescence in the bacterial reaction center induced by entangled light demonstrate a selectivity of double-exciton states which is not possible using classical stochastic light with the same power spectrum.Comment: 11 pages, 13 figures, published versio

Testing a model of minority identity achievement, identity affirmation, and psychological well-being among ethnic minority and sexual minority individuals

How is social identity related to psychological well-being among minority individuals? Drawing on developmental models of identity formation (e.g., Erikson, 1968) and on Social Identity Theory (Tajfel & Turner, 1979), we tested a conceptual model examining links between two key aspects of social identity and psychological well-being. We proposed that the association between identity achievement (exploring and understanding the meaning of one\u27s identity) and psychological well-being is mediated by identity affirmation (developing positive feelings and a sense of belonging to one\u27s social group). Across three studies, including ethnic minority high school students (Study 1), ethnic minority college students (Study 2) and lesbian and gay male adults (Study 3), we found strong support for the model. Results suggest that the process of exploring and understanding one\u27s minority identity can serve as an important basis for developing positive feelings toward and an enhanced sense of attachment to the group, which can in turn confer psychological benefits for minority individuals. Implications and directions for future research are discussed

Cost-effectiveness of alternative methods of surgical repair of inguinal hernia

Objectives: To assess the relative cost-effectiveness of laparoscopic methods of inguinal hernia repair compared with open flat mesh and open non-mesh repair. Methods: Data on the effectiveness of these alternatives came from three systematic reviews comparing: (i) laparoscopic methods with open flat mesh or non-mesh methods; (ii) open flat mesh with open non-mesh repair; and (iii) methods that used synthetic mesh to repair the hernia defect with those that did not. Data on costs were obtained from the authors of economic evaluations previously conducted alongside trials included in the reviews. A Markov model was used to model cost-effectiveness for a five-year period after the initial operation. The outcomes of the model were presented using a balance sheet approach and as cost per hernia recurrence avoided and cost per extra day at usual activities. Results: Open flat mesh was the most cost-effective method of preventing recurrences. Laparoscopic repair provided a shorter period of convalescence and less long-term pain compared with open flat mesh but was more costly. The mean incremental cost per additional day back at usual activities compared with open flat mesh was €38 and €80 for totally extraperitoneal and transabdominal preperitoneal repair, respectively. Conclusions: Laparoscopic repair is not cost-effective compared with open flat mesh repair in terms of cost per recurrence avoided. Decisions about the use of laparoscopic repair depend on whether the benefits (reduced pain and earlier return to usual activities) outweigh the extra costs and intraoperative risks. On the evidence presented here, these extra costs are unlikely to be offset by the short-term benefits of laparoscopic repair.Luke Vale, Adrian Grant, Kirsty McCormack, Neil W. Scott and the EU Hernia Trialists Collaboratio

Nonlinear spectroscopy of chromophore aggregates with entangled photon pulses

Abstract. The response of the bacterial reaction center to entangled photons is com pared with stochastic and chirped pulses. Nonlinear optical signals reveal how distribu tions of exciton states may be controlled by quantum light. Nonlinear spectroscopy with quantum light Quantum light provides novel possibilities for nonlinear spectroscopy by tuning parameters of the pho ton wavefunction. Frequency-entangled photons possess various attractive features for spectroscopic applications. The coherent interaction of pairs of photons scales linearly in the pump intensity, thus allowing for much lower light intensities for nonlinear signal

Steric Hindrance of NH3 Diffusion on Pt(111) by Co-Adsorbed O-Atoms

A detailed velocity-resolved kinetics study of NH3 thermal desorption rates from p(2 × 2) O/Pt(111) is presented. We find a large reduction in the NH3 desorption rate due to adsorption of O-atoms on Pt(111). A physical model describing the interactions between adsorbed NH3 and O-atoms explains these observations. By fitting the model to the derived desorption rate constants, we find an NH3 stabilization on p(2 × 2) O/Pt(111) of 0.147–0.014+0.023 eV compared to Pt(111) and a rotational barrier of 0.084–0.022+0.049 eV, which is not present on Pt(111). The model also quantitatively predicts the steric hindrance of NH3 diffusion on Pt(111) due to co-adsorbed O-atoms. The derived diffusion barrier of NH3 on p(2 × 2) O/Pt(111) is 1.10–0.13+0.22 eV, which is 0.39–0.14+0.22 eV higher than that on pristine Pt(111). We find that Perdew Burke Ernzerhof (PBE) and revised Perdew Burke Ernzerhof (RPBE) exchange–correlation functionals are unable to reproduce the experimentally observed NH3–O adsorbate–adsorbate interactions and NH3 binding energies at Pt(111) and p(2 × 2) O/Pt(111), which indicates the importance of dispersion interactions for both systems

Laparoscopic peritoneal lavage: A definitive treatment for diverticular peritonitis or a "bridge" to elective laparoscopic sigmoidectomy?

To this day, the treatment of generalized peritonitis secondary to diverticular perforation is still controversial. Recently, in patients with acute sigmoid diverticulitis, laparoscopic lavage and drainage has gained a wide interest as an alternative to resection. Based on this backdrop, we decided to perform a systematic review of the literature to evaluate the safety, feasibility, and efficacy of peritoneal lavage in perforated diverticular disease. A bibliographic search was performed in PubMed for case series and comparative studies published between January 1992 and February 2014 describing laparoscopic peritoneal lavage in patients with perforated diverticulitis. A total of 19 articles consisting of 10 cohort studies, 8 case series, and 1 controlled clinical trial met the inclusion criteria and were reviewed. In total these studies analyzed data from 871 patients. The mean follow-up time ranged from 1.5 to 96 months when reported. In 11 studies, the success rate of laparoscopic peritoneal lavage, defined as patients alive without surgical treatment for a recurrent episode of diverticulitis, was 24.3%. In patients with Hinchey stage III diverticulitis, the incidence of laparotomy conversion was 1%, whereas in patients with stage IV it was 45%. The 30-day postoperative mortality rate was 2.9%. The 30-day postoperative reintervention rate was 4.9%, whereas 2% of patients required a percutaneous drainage. Readmission rate after the first hospitalization for recurrent diverticulitis was 6%. Most patients who were readmitted (69%) required redo surgery. A 2-stage laparoscopic intervention was performed in 18.3% of patients. Laparoscopic peritoneal lavage should be considered an effective and safe option for the treatment of patients with sigmoid diverticulitis with Hinchey stage III peritonitis; it can also be consider as a “bridge” surgical step combined with a delayed and elective laparoscopic sigmoidectomy in order to avoid a Hartmann procedure. This minimally invasive staged approach should be considered for patients without systemic toxicity and in centers experienced in minimally invasive surgery techniques. Further evidence is needed, and the ongoing RCTs will better define the role of the laparoscopic peritoneal lavage/drainage in the treatment of patients with complicated diverticulitis