Tabu search for scheduling on identical parallel machines to minimize mean tardiness

This paper presents a tabu search approach for scheduling jobs on identical parallel machines with the objective of minimizing the mean tardiness. Initially, we consider a basic tabu search that uses short term memory only. Local search is performed on a neighborhood defined by two types of moves. Insert moves consist of transferring each job from one machine to another and swap moves are those obtained by exchanging each pair of jobs between two machines. Next, we analyze the incorporation of two diversification strategies with the aim of exploring unvisited regions of the solution space. The first strategy uses long term memory to store the frequency of the moves executed throughout the search and the second makes use of influential moves. Computational tests are performed on problems with up to 10 machines and 150 jobs. The heuristic performance is evaluated through a lower bound given by Lagrangean relaxation. A comparison is also made with respect to the best constructive heuristic reported in the literature.     

Mutuality and Reciprocity in the Psychological Contracts of Employees and Employers.

The authors assessed the joint perceptions of the employee and his or her employer to examine mutuality and reciprocity in the employment relationship. Paired psychological contract reports were obtained from 80 employee-employer dyads in 16 university-based research centers. On the basis of in-depth study of the research setting, research directors were identified as primary agents for the university (employer) in shaping the terms of employment of staff scientists (employees). By assessing the extent of consistency between employee and employer beliefs regarding their exchange agreement, the present study mapped the variation and consequences of mutuality and reciprocity in psychological contracts. Results indicate that both mutuality and reciprocity are positively related to archival indicators of research productivity and career advancement, in addition to self-reported measures of Met Expectations and intention to continue working with the employer. Implications for psychological contract theory are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hope-focused practices during early psychotherapy sessions: Part I: Implicit approaches.

Hope is recognized as one of four key factors contributing to psychotherapeutic change across a variety theoretical approaches (Hubble, Duncan, & Miller, 1999), especially early in the psychotherapeutic sequence. To date little research has looked at how hope is translated into specific practices by psychotherapists during psychotherapy sessions. This case study employed basic interpretive inquiry (Merriam, 1998) to explore the hope-focused practices of five hope-educated psychotherapists with 11 clients early in the therapy sequence. Two categories characterize the overall findings, that is, implicit and explicit hope-focused practices. This first paper in a two-part research report focuses on implicit hope-focused interventions. Implicit hope-focused interventions were those practices identified by therapists as addressing client hope without employing the word hope explicitly. Implicit hope practices addressed two key aspects of therapy, (a) attending to therapeutic relationship, and (b) fostering client perspective change. The second paper in this series examines findings regarding explicit hope-focused interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous reconstruction of evolutionary history and epidemiological dynamics from viral sequences with the birth–death SIR model

The evolution of RNA viruses, such as human immunodeficiency virus (HIV), hepatitis C virus and influenza virus, occurs so rapidly that the viruses'' genomes contain information on past ecological dynamics. Hence, we develop a phylodynamic method that enables the joint estimation of epidemiological parameters and phylogenetic history. Based on a compartmental susceptible–infected–removed (SIR) model, this method provides separate information on incidence and prevalence of infections. Detailed information on the interaction of host population dynamics and evolutionary history can inform decisions on how to contain or entirely avoid disease outbreaks. We apply our birth–death SIR method to two viral datasets. First, five HIV type 1 clusters sampled in the UK between 1999 and 2003 are analysed. The estimated basic reproduction ratios range from 1.9 to 3.2 among the clusters. All clusters show a decline in the growth rate of the local epidemic in the middle or end of the 1990s. The analysis of a hepatitis C virus genotype 2c dataset shows that the local epidemic in the Córdoban city Cruz del Eje originated around 1906 (median), coinciding with an immigration wave from Europe to central Argentina that dates from 1880 to 1920. The estimated time of epidemic peak is around 1970.     

Using Twitter® as source of information for dietary market research: a study on veganism and plant-based diets

Social media has experienced rapid growth in recent years and has been subjected of discussions on a wide range of topics including new lifestyles and eating habits, providing a great opportunity to obtain spontaneous consumer information. In this sense, the present work aimed to understand the perception of Twitter^® users about themes of veganism and plant-based diets. The social networking data mining methodology was applied to measure the relationship between both terms. The significant differences found were analysed using the global chi-square (χ²) test, and their sources of variation were investigated by the chi-square per cell. The results indicate that the vegan group's posts are more related to the categories of recipes, trends, criticism and negative comments about veganism, being more often citing sources when compared to the other group. The results of the plant-based diet group are more significantly related to the impacts of nutrition, physical activity and consumer health. In conclusion, Twitter^® has proved to be an interesting tool for obtaining data on (re) produced food publications on social media and their results can guide the market and the academic environment in creating new products, services and marketing strategies to answer the needs of specific consumers.     

Influence of mesostasis in volcanic rocks on the alkali-aggregate reaction

Mesostasis material present in the interstices of volcanic rocks is the main cause of the alkali-aggregate reaction (AAR) in concretes made with these rock aggregates. Mesostasis often is referred to as volcanic glass, because it has amorphous features when analyzed by optical microscopy. However, this study demonstrates that mesostasis in the interstitials of volcanic rocks most often consists of micro to cryptocrystalline mineral phases of quartz, feldspars, and clays. Mesostasis has been identified as having different characteristics, and, thus, this new characterization calls for a re-evaluation of their influence on the reactivity of the volcanic rocks. The main purpose of this study is to correlate the characteristics of mesostasis with the AAR in mortar bars containing basalts and rhyolites.     

Inactivation of Neosartorya fischeri and Paecilomyces variotii on paperboard packaging material by hydrogen peroxide and heat

This study reports on the influence of heat and hydrogen peroxide combination on the inactivation kinetics of two heat resistant molds: Neosartorya fischeri and Paecilomyces variotii. Spores of different ages (1 and 4 months) of these molds were prepared and D-values (the time required at certain temperature/hydrogen peroxide combination to inactivate 90% of the mold ascospores) were determined using thermal death tubes. D-values found for P. variotii ranged from 1.2 to 25.1 s after exposure to different combinations of heat (40 or 60 °C) and hydrogen peroxide (35 or 40% w/w) while for N. fischeri they varied from 2.7 to 14.3 s after exposure to the same hydrogen peroxide concentrations and higher temperatures (60 or 70 °C). The influence of temperature and hydrogen peroxide concentration on the d-values varied with the genus of mold and their ages. A synergistic effect of heat and hydrogen peroxide in reducing D-values of Paecilomyces variotti and N. fischeri has been observed. In addition to strict control of temperature, time and hydrogen concentration, hygienic storage and handling of laminated paperboard material must be considered to reduce the probability of package’s contamination. All these measures together will ensure package’s sterility that is imperative for the effectiveness of aseptic processing and consequently to ensure the microbiological stability of processed foods during shelf-life.     

The Effect of Relationship Characteristics and Relational Communication on Experiences of Hurt From Romantic Partners

This study expands the relational turbulence model (RTM; Solomon & Knobloch,) by theorizing about how characteristics of relationships and relational judgments influence people's experiences of hurtful messages. Previous applications of RTM to hurt have uncovered associations among relational characteristics that influence people's hurtful experiences; however, the process by which these characteristics influence experiences of hurt remains unclear. We propose that relational communication (specifically, perceptions of dominance, and disaffiliation) is the mechanism linking relational qualities to hurt. A multigroup SEM was conducted to test for the possibility of sex differences. Results showed that people's experiences of hurt vary as a function of both relationship characteristics and relational inferences. Results also indicated a difference in path coefficients for males and females.     

Zinc supplementation of Friesian cows: Effect on chemical-nutritional composition and aromatic profile of dairy products

Zinc represents an essential microelement for several biochemical mechanisms. The body's inability to store zinc necessarily requires a constant dietary supply to avoid alteration of physiological functions. The aim of the present study was to investigate the effect of dietary enrichment with zinc on chemical-nutritional and aromatic properties of milk and cheese. Thirty commercial dairy cows, balanced for parity, milk production, and days in milk, were randomly assigned to 2 groups. The control group was fed with a conventional complete diet (22 kg of dry matter/animal per day), whereas the experimental group received a daily zinc supplementation of 60 mg per kg of dry complete feed. During the experimental period, the milk yield was monitored and samples of milk and caciotta cheese were collected to obtain information about the chemical-nutritional composition and aromatic profile. Dietary zinc integration did not influence milk yield and composition, but induced a marked reduction of somatic cell count and improved the oxidative stability of ripened caciotta cheese. In both milk and cheese, the experimental group samples were characterized by a lower concentration of saturated fatty acids and an increase in oleic acid, vaccenic acid, and rumenic acid. The aromatic profile of dairy products was also positively affected by dietary zinc intake, with an increase in concentration of carboxylic acids, aldehydes, and esters. The present results suggest a positive role of zinc in improving animal health and nutraceutical properties of milk and corresponding cheese. Taking into account the analysis of volatile compounds, zinc dietary supplementation of dairy cows should contribute to the production of cheeses with interesting organoleptic properties, although more studies are necessary to confirm the consumer acceptability of these changes.     

Deployment of fuel cell vehicles in China: Greenhouse gas emission reductions from converting the heavy-duty truck fleet from diesel and natural gas to hydrogen

Hydrogen fuel cells, as an energy source for heavy duty vehicles, are gaining attention as a potential carbon mitigation strategy. Here we calculate the greenhouse gas (GHG) emissions of the Chinese heavy-duty truck fleet under four hydrogen fuel cell heavy-duty truck penetration scenarios from 2020 through 2050. We introduce Aggressive, Moderate, Conservative and No Fuel Cell Vehicle (No FCV) scenarios. Under these four scenarios, the market share of heavy-duty trucks powered by fuel cells will reach 100%, 50%, 20% and 0%, respectively, in 2050. We go beyond previous studies which compared differences in GHG emissions from different hydrogen production pathways. We now combine an analysis of the carbon intensity of various hydrogen production pathways with predictions of the future hydrogen supply structure in China along with various penetration rates of heavy-duty fuel cell vehicles. We calculate the associated carbon intensity per vehicle kilometer travelled of the hydrogen used in heavy-duty trucks in each scenario, providing a practical application of our research. Our results indicate that if China relies only on fuel economy improvements, with the projected increase in vehicle miles travelled, the GHG emissions of the heavy-duty truck fleet will continue to increase and will remain almost unchanged after 2025. The Aggressive, Moderate and Conservative FCV Scenarios will achieve 63%, 30% and 12% reductions, respectively, in GHG emissions in 2050 from the heavy duty truck fleet compared to the No FCV Scenario. Additional reductions are possible if the current source of hydrogen from fossil fuels was displaced with increased use of hydrogen from water electrolysis using non-fossil generated electricity.