311 research outputs found

    Adaptive polarization separation

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    A broadband adaptively controlled polarization separation network is discussed. Two transmitted signals vertically and horizontally polarized are received as elliptically polarized signals. If there is any vertical polarization on the other signal the separation network provides two signals. The separation is done automatically by the use of two sets of crosscouplers which couple a single line to the other line to complete the polarization decoupling operation

    Shifts in Attack Behavior of an Important Kelp Forest Predator Within Marine Reserves

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    Marine reserves have become increasingly valuable tools with which to manage ecosystems. These reserves consistently restore populations of top predators, often reducing availability of their favored prey. We hypothesized that such prey reduction in reserves causes protected predators to alter their attack behavior to include less palatable prey, potentially amplifying top-down effects on community structure. To test this hypothesis, we presented the relatively unpalatable sea hare Aplysia californica to freely foraging spiny lobsters Panulirus interruptus in 4 marine no-take reserves, each paired with an adjacent fished area. We found that lobsters only attacked sea hares inside reserves, where lobster density was significantly greater than that of the adjacent fished areas. Attacks on otherwise unpalatable prey exclusively in no-take reserves was likely caused by increased hunger, since in the laboratory only food-deprived lobsters attacked sea hares. These findings are the first to suggest that management involving no-take reserves may have unintended consequences on community structure that result from behavioral changes in key predators in the face of increased competition for food. We suspect that these effects may become more widely detected as reserves across the globe grow older and are researched further

    New multiport robotic surgical systems: a comprehensive literature review of clinical outcomes in urology

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    Over the past 20 years, the field of robotic surgery has largely been dominated by the da Vinci robotic platform. Nevertheless, numerous novel multiport robotic surgical systems have been developed over the past decade, and some have recently been introduced into clinical practice. This nonsystematic review aims to describe novel surgical robotic systems, their individual designs, and their reported uses and clinical outcomes within the field of urologic surgery. Specifically, we performed a comprehensive review of the literature regarding the use of the Senhance robotic system, the CMR-Versius robotic system, and the Hugo RAS in urologic procedures. Systems with fewer published uses are also described, including the Avatera, Hintori, and Dexter. Notable features of each system are compared, with a particular emphasis on factors differentiating each system from the da Vinci robotic system

    Contemporary urologic minilaparoscopy : indications, techniques, and surgical outcomes in a multi-institutional European cohort

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    OBJECTIVES: To provide an analytical overview of contemporary indications, techniques, and outcomes of urologic minilaparoscopy (ML) in multiple European centers. METHODS: Data of patients who had undergone a minilaparoscopic urologic procedure at nine European institutions between 2009 and 2012 were retrospectively gathered. Surgical procedures were classified as upper or lower urinary tract and as ablative or extirpative and reconstructive. The main surgical outcome parameters were analyzed and relevant operative data related to the surgical technique were recorded. RESULTS: Overall, 192 patients (mean age 45.25±17.8 years) were included in the analysis. Most of them were nonobese (mean body mass index [BMI] 24.7±3.6?kg/m(2)) at low estimated surgical risk (mean American Society of Anesthesiologists [ASA] 1.69±0.68). Indications for surgery were mostly nononcologic (132 cases, 68.8%). Most of the procedures were done in the upper urinary tract (133 cases, 69.2%) and were mostly with a reconstructive intent (109 cases, 56.7%). Overall operative time was 132.7±52.3 minutes with an estimated blood loss of 60.9±47.6?mL while the mean hospital stay was 5±2.1 days. Most of the postoperative complications were low Clavien grade (1 and 2), with only one (0.5%) grade 3 and one (0.5%) grade 4 complications recorded. CONCLUSIONS: A broad range of common procedures can be safely and effectively performed with ML techniques. By duplicating the principles of standard laparoscopy, but potentially offering less surgical scar and trauma, ML can be regarded as a viable option when looking for a virtually "scarless" surgery

    Laparoscopic Radical Prostatectomy in Patients with High-Risk Prostate Cancer: Feasibility and Safety. Results of a Multicentric Study

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    Introduction: In Western countries about 25% of prostate cancer (PCa) are high-risk tumors at presentation and its treatment is still a matter of debate among urologists. When a surgical approach is preferred the use of a mininvasive tecnique is still difficult due to the lack of data supporting it in literature. The aim of this study is to evaluate feasibility and safety of laparoscopic radical prostatectomy (LRP) for high-risk PCa. Materials and Methods: The study included 1114 patients with high-risk PCa submitted to LRP between 1998 and 2014. High-risk patients were defined according to D'Amico classification. We collected functional and oncological long-term outcomes and evaluated with univariate and multivariate analyses the role of predictive factors for survival and biochemical recurrence (BR). Results: Mean age at treatment was 628 years; mean follow-up was 74 +/- 50 months. We obtained an overall survival (OS) of 96.6% at a mean follow-up of 74 months (1076 patients) and a disease-free survival of 66.2% (737 patients). Age (p=0.0006), pT (p<0.0001), pN (p=0.0018), and surgical margins (p=0.0076) resulted as independent predictors for BR in multivariate analysis. pN (p=0.0025) and Gs (p=0.0003) are independent predictors for OS and cancer-specific survival in a univariate analysis; just the Gs results significant in the multivariate model. Conclusions: According to our encouraging data about oncological and functional outcomes we believe that radical prostatectomy represents an effective treatment for patients with high-risk PCa and that laparoscopy is a safe approach offering a mini-invasive alternative to open surgery
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