Theory of orientational ordering in colloidal molecular crystals

Freezing of charged colloids on square or triangular two-dimensional periodic substrates has been recently shown to realize a rich variety of orientational orders. We propose a theoretical framework to analyze the corresponding structures. A fundamental ingredient is that a non spherical charged object in an electrolyte creates a screened electrostatic potential that is anisotropic at any distance. Our approach is in excellent agreement with the known experimental and numerical results, and explains in simple terms the reentrant orientational melting observed in these so called colloidal molecular crystals. We also investigate the case of a rectangular periodic substrate and predict an unusual phase transition between orientationnaly ordered states, as the aspect ratio of the unit cell is changed.Comment: 4 pages, to appear in Phys. Rev. Let

Lagrangian relaxation bounds for a production-inventory-routing problem

We consider a single item Production-Inventory-Routing problem with a single producer/supplier and multiple retailers. Inventory management constraints are considered both at the producer and at the retailers, following a vendor managed inventory approach, where the supplier monitors the inventory at retailers and decides on the replenishment policy for each retailer. We assume a constant production capacity. Based on the mathematical formulation we discuss a classical Lagrangian relaxation which allows to decompose the problem into four subproblems, and a new Lagrangian decomposition which decomposes the problem into just a production-inventory subproblem and a routing subproblem. The new decomposition is enhanced with valid inequalities. A computational study is reported to compare the bounds from the two approaches

Variations in platelet proteins associated with st-elevation myocardial infarction: Novel clues on pathways underlying platelet activation in acute coronary syndromes

OBJECTIVE: Our aim in this study was to provide novel information on the molecular mechanisms playing a major role in the unwanted platelet activation associated with ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: We compared the platelet proteome of 11 STEMI patients to a matched control group of 15 stable chronic ischemic cardiopathy patients. In addition, we did a prospective study to follow the STEMI patients over time. Proteins were separated by high-resolution 2D gel electrophoresis, identified by mass spectrometry, and validated by Western blotting. Platelets from STEMI patients on admission displayed 56 protein spot differences (corresponding to 42 unique genes) compared with the control group. The number of differences decreased with time during the patients' follow-up. Interestingly, the adapter protein CrkL and the active form of Src (phosphorylated in Tyr418) were found to be upregulated in platelets from STEMI patients. Major signaling pathways related to the proteins identified include integrin, integrin-linked kinase, and glycoprotein VI (GPVI) signaling. Interestingly, a study on an independent cohort of patients showed a higher degree of activation of GPVI signaling in STEMI patients. CONCLUSIONS: CrkL, the active form of Src, and GPVI signaling are upregulated in platelets from STEMI patients

Prevention of ventilator-associated pneumonia: the multimodal approach of the spanish ICU pneumonia zero program.

Objectives: The “Pneumonia Zero” project is a nationwide multimodal intervention based on the simultaneous implementation of a comprehensive evidence-based bundle measures to prevent ventilator-associated pneumonia in critically ill patients admitted to the ICU. Design: Prospective, interventional, and multicenter study. Setting: A total of 181 ICUs throughout Spain. Patients: All patients admitted for more than 24 hours to the participating ICUs between April 1, 2011, and December 31, 2012. Intervention: Ten ventilator-associated pneumonia prevention measures were implemented (seven were mandatory and three highly recommended). The database of the National ICU-Acquired Infections Surveillance Study (Estudio Nacional de Vigilancia de Infecciones Nosocomiales [ENVIN]) was used for data collection. Ventilator-associated pneumonia rate was expressed as incidence density per 1,000 ventilator days. Ventilator-associated pneumonia rates from the incorporation of the ICUs to the project, every 3 months, were compared with data of the ENVIN registry (April–June 2010) as the baseline period. Ventilator-associated pneumonia rates were adjusted by characteristics of the hospital, including size, type (public or private), and teaching (postgraduate) or university-affiliated (undergraduate) status. Measurements and Main Results: The 181 participating ICUs accounted for 75% of all ICUs in Spain. In a total of 171,237 ICU admissions, an artificial airway was present on 505,802 days (50.0% of days of stay in the ICU). A total of 3,474 ventilator-associated pneumonia episodes were diagnosed in 3,186 patients. The adjusted ventilator-associated pneumonia incidence density rate decreased from 9.83 (95% CI, 8.42–11.48) per 1,000 ventilator days in the baseline period to 4.34 (95% CI, 3.22–5.84) after 19–21 months of participation. Conclusions: Implementation of the bundle measures included in the “Pneumonia Zero” project resulted in a significant reduction of more than 50% of the incidence of ventilator-associated pneumonia in Spanish ICUs. This reduction was sustained 21 months after implementation

Constituents of Ipomoea horrida Humber ex ducke: spectroscopic identification of the flavonoids

As part of a systematic investigation of the Ipomoea species of Northeastern Brazil, a mixture of 7,4'-di­O-methylkaempferol and 7,3',4'-tri-O­methylquercetin were identified in extracts obtained from the aerial parts of Ipomoea horrida

Combined ship routing and inventory management in the salmon farming industry

We consider a maritime inventory routing problem for Norway's largest salmon farmer both producing the feed at a production factory and being responsible for fish farms located along the Norwegian coast. The company has bought two new ships to transport the feed from the factory to the fish farms and is responsible for the routing and scheduling of the ships. In addition, the company has to ensure that the feed at the production factory as well as at the fish farms is within the inventory limits. A mathematical model of the problem is presented, and this model is reformulated to improve the efficiency of the branch-and-bound algorithm and tightened with valid inequalities. To derive good solutions quickly, several practical aspects of the problem are utilized and two matheuristics developed. Computational results are reported for instances based on the real problem of the salmon farmer

Algorithm Engineering in Robust Optimization

Robust optimization is a young and emerging field of research having received a considerable increase of interest over the last decade. In this paper, we argue that the the algorithm engineering methodology fits very well to the field of robust optimization and yields a rewarding new perspective on both the current state of research and open research directions. To this end we go through the algorithm engineering cycle of design and analysis of concepts, development and implementation of algorithms, and theoretical and experimental evaluation. We show that many ideas of algorithm engineering have already been applied in publications on robust optimization. Most work on robust optimization is devoted to analysis of the concepts and the development of algorithms, some papers deal with the evaluation of a particular concept in case studies, and work on comparison of concepts just starts. What is still a drawback in many papers on robustness is the missing link to include the results of the experiments again in the design