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Random convex programs are convex optimization problems that are robust with respect to a finite number of randomly sampled instances of an uncertain variable δ. This paper studies random convex programs in which there is uncertainty in the objective function. Specifically, let L(x, δ) be a loss function that is convex in x, the optimization variable, while it has an arbitrary dependence on the random variable d representing uncertainty in the optimization problem. After sampling N instances δ(1), δ(N) of the random variable δ, the random convex program can be written as follows: minx maxi L(x, δ(i)). The fundamental feature of this program is that its value LN* = maxi L(xN*,δ(i)), where xN* is the solution, remains guaranteed when xN* is applied to the vast majority of the other unseen instances of δ; that is, L(xN*, δ) ≤ LN* holds with high probability with respect to the uncertain variable δ. This generalization property has justified a systematic and rigorous use of randomization in robust optimization. In this paper, we introduce L1-regularization in random convex programs and show that L1-regularization boosts the above generalization property so that generalization is achieved with significantly fewer samples than in the standard convex program given above. Explicit bounds are derived that allow a rigorous and easy implementation of the method. [ABSTRACT FROM AUTHOR]

Many engineering problems can be cast as optimization problems subject to convex constraints that are parameterized by an uncertainty or ‘instance’ parameter. Two main approaches are generally available to tackle constrained optimization problems in presence of uncertainty: robust optimization and chance-constrained optimization. Robust optimization is a deterministic paradigm where one seeks a solution which simultaneously satisfies all possible constraint instances. In chance-constrained optimization a probability distribution is instead assumed on the uncertain parameters, and the constraints are enforced up to a pre-specified level of probability. Unfortunately however, both approaches lead to computationally intractable problem formulations.In this paper, we consider an alternative ‘randomized’ or ‘scenario’ approach for dealing with uncertainty in optimization, based on constraint sampling. In particular, we study the constrained optimization problem resulting by taking into account only a finite set ofNconstraints, chosen at random among the possible constraint instances of the uncertain problem. We show that the resulting randomized solution fails to satisfy only a small portion of the original constraints, provided that a sufficient number of samples is drawn. Our key result is to provide an efficient and explicit bound on the measure (probability or volume) of the original constraints that are possibly violated by the randomized solution. This volume rapidly decreases to zero asNis increased. [ABSTRACT FROM AUTHOR]

The purpose of the article is to show how the location of new firms differs according to the life cycle stages of their industry in Spanish cities. In the initial stages of the product life cycle, the products are not totally defined and the innovative activity of firms is high. After that, when the product design is standardized, specific equipment goods appear, the profit margin of firms is reduced and the capacity to innovate also diminishes. The theory of the product life cycle is a suitable instrument for analyzing why new manufacturing plants tend to start up in a small number of places, and why the decisions of new firms as to where to locate change with this life cycle.

Sialoadenectomy for sialolithiasis is necessary when the stone cannot be removed through the salivary duct. In addition, extracorporeal. shock-wave lithotripsy has recently become available for this purpose. The safety and efficacy of this method was assessed in 52 outpatients bearing stones with an average diameter of 6.76 mm in the submandibular or parotid gland. Anesthetics, sedatives, and analgesics were not required. Twenty-four of the 36 patients with submandibular gland calculi and all 16 with parotid sialolithiasis had complete stone disintegration or fragmentation of the calculi, with possible spontaneous clearance. Untoward effects were observed in 15 patients, namely localized skin petecchiae, transitory swelling of the gland, and self-limiting bleeding from the duct. No persistent damage of the salivary glands or adjacent structures was noted during a mean follow-up period of 10 months. [ABSTRACT FROM AUTHOR]

Abstract Background Under normal solar fluence, UV-B damages macromolecules, but it also elicits physiological acclimation and developmental changes in plants. Excess UV-B decreases crop yield. Using a treatment twice solar fluence, we focus on discovering signals produced in UV-B-irradiated maize leaves that translate to systemic changes in shielded leaves and immature ears. Results Using transcriptome and proteomic profiling, we tracked the kinetics of transcript and protein alterations in exposed and shielded organs over 6 h. In parallel, metabolic profiling identified candidate signaling molecules based on rapid increase in irradiated leaves and increased levels in shielded organs; pathways associated with the synthesis, sequestration, or degradation of some of these potential signal molecules were UV-B-responsive. Exposure of just the top leaf substantially alters the transcriptomes of both irradiated and shielded organs, with greater changes as additional leaves are irradiated. Some phenylpropanoid pathway genes are expressed only in irradiated leaves, reflected in accumulation of pathway sunscreen molecules. Most protein changes detected occur quickly: approximately 92% of the proteins in leaves and 73% in immature ears changed after 4 h UV-B were altered by a 1 h UV-B treatment. Conclusions There were significant transcriptome, proteomic, and metabolomic changes under all conditions studied in both shielded and irradiated organs. A dramatic decrease in transcript diversity in irradiated and shielded leaves occurs between 0 h and 1 h, demonstrating the susceptibility of plants to short term UV-B spikes as during ozone depletion. Immature maize ears are highly responsive to canopy leaf exposure to UV-B.

Abstract Background In order to identify relevant targets for change, it is essential to know the reliability of incident staff reporting. The aim of this study is to compare the incidence and type of unintended events (UE) reported by facilitated Intensive Care Unit (ICU) staff with those recorded concurrently by an observer. Methods The study is a prospective data collection performed in two 4-bed multidisciplinary ICUs of a teaching hospital. The format of the UE reporting system was voluntary, facilitated and not necessarily anonymous, and used a structured form with a predetermined list of items. UEs were reported by ICU staff over a period of 4 weeks. The reporting incidence during the first fourteen days was compared with that during the second fourteen. During morning shifts in the second fourteen days, one observer in each ICU recorded any UE seen. The staff was not aware of the observers' study. The incidence of UEs reported by staff was compared with that recorded by the observers. Results The staff reported 36 UEs in the first fourteen days and 31 in the second.. The incidence of UE detection during morning shifts was significantly higher than during afternoon or night shifts (p < 0.001). Considering only working day morning shifts, the rate of UE reporting by the staff per 100 patient days was 26.9 (CI 95% 16.9–37.0) in the first fourteen day period and 20.3 (CI 95% 10.3–30.4) in the second. The rate of UE detection by the observers was 53.1 per 100 patient days (CI 95% 40.6–65.6), significantly higher (p < 0.001) than that reported concurrently by the staff. There was excellent agreement between staff and observers about the severity of the UEs recorded (Intraclass Correlation Coefficient 0.869). The observers recorded mainly UEs involving Airway/mechanical ventilation and Patient management, and the staff Catheter/Drain/Probe and Medication errors (p = 0.025). Conclusion UE incidence is strongly underreported by staff in comparison with observers. Also the types of UEs reported are different. Invaluable information about incidents in ICU can be obtained in a few days by observer monitoring.

The article focuses on the aspects of genetic, clinical, and treatment of colorectal polyposis disorders such as familial adenomatous polyposis (FAP) and multiple colorectal adenomas (MCRAs) syndromes. Among the clinical aspects discussed are genetic cause, physiological manifestation, and pathological characteristics. Also discussed several surgical methods including total colectomy with ileo-rectal anastomosis (IRA), laparoscopic approach, and protocolectomy.