Emergent network structure and initial group performance: The moderating role of pre‐existing relationships

Organization restructurings often put groups of employees into new teams and roles, and it is not unusual for some of these new teammates to have pre‐existing work and friendship relationships. While there has been much theorizing on the impact of existing social network structures on group performance, there has been less research on how pre‐existing relationships help or hinder initial group performance, especially in teams with interdependent roles and tasks. We explore several hypotheses in a competitive management simulation involving 42 teams and find that (1) the density of pre‐existing work and friendship relationships are directly associated with higher initial group performance, and (2) pre‐existing work network density moderates the relationship between emergent work network density and initial group performance. In other words, the degree to which emergent work ties are based on pre‐existing work relationships (i.e., former co‐workers actually work together in their new roles) also contributes to higher initial group productivity. Copyright © 2009 John Wiley & Sons, Ltd.     

Insecticidal activity of different extracts from Scrophularia canina L. against Culex pipiens molestus Forskal (Diptera, Culicidae)

The insecticidal activity of different extracts (aqueous, methyl alcohol, hexane and petroleum ether) of the aerial part of Scrophularia canina against the second and fourth-instar larvae and adult females of Culex pipiens molestus was investigated. The larvicidal activity of all the extracts was tested in the dose range from 7.8 to 1000 ppm. The highest toxicity was exhibited by the petroleum ether extract against second-instar larvae (48 h LC?? = 23.5 ppm) and by the hexane extract against fourth-instar larvae (48 h LC?? = 23.6 ppm). Methyl alcohol and aqueous extracts did not show any larvicidal activity. Sub-lethal doses of petroleum ether and hexane extracts induced increasing mortalities during 13 days after treatment but did not affect the duration of larval and pupal stages. In persistence tests, the hexane extract retained a satisfactory larvicidal activity after a 10-day period of test solutions incubation. Topical treatment of adult females with doses from 0.25 to 8 μg per mg of female body weight of different extracts showed a similar toxicity for the hexane (24 h LD?? = 1.7 μg mg?1) and petroleum ether (24 h LD?? = 1.8 μg mg?1) extracts which were significantly more toxic than methyl alcohol extract (4.2 μg mg?1). Aqueous extract did not induce adult mortality. The marked mosquitocidal activity of petroleum ether and hexane extracts of the aerial part of S. canina against different life stages of C. pipiens molestus is promising to develop effective alternatives to synthetic insecticides.     

Investigation of volatile organic compounds and phthalates present in the cabin air of used private cars

The presence of selected volatile organic compounds (VOCs) including aromatic, aliphatic compounds and low molecular weight carbonyls, and a target set of phthalates were investigated in the interior of 23 used private cars during the summer and winter. VOC concentrations often exceeded levels typically found in residential indoor air, e.g. benzene concentrations reached values of up to 149.1 µg m^− 3. Overall concentrations were 40% higher in summer, with temperatures inside the cars reaching up to 70 °C. The most frequently detected phthalates were di-n-butyl-phthalate and bis-(2-ethylhexyl) phthalate in concentrations ranging from 196 to 3656 ng m^− 3.     

VTOL aircraft in emergency planning and management: a model for a helipad network

The scientific literature regarding HEMS (Helicopter Emergency Medical Service) planning lacks a method for defining optimal sites for helipads that takes into account risk distribution and hospital location. Such a method could minimise overall rescue time in emergency situations. In this paper a method that supports the decisions taken by disaster planners and managers is developed, focusing on the quantification of necessary air resources for the management of some probable calamities. Given a region characterised by a natural and non-natural disaster risk map, along with a comprehensive transport system (also characterised by a risk map), a set of emergency destinations (hospitals), a set of heliports/helipads dislocated on the territory and a number of available HEMS rotorcraft, the aim of the paper is to assess the adequacy of the VTOL/FATO (Vertical Take-Off and Landing/Final Take-Off and Landing Area) system in order to deal with a set of possible emergencies.     

Mechanochemistry of ibuprofen pharmaceutical

In this paper mechanochemistry has been studied in view of possible application to detoxification of expired pharmaceuticals. The experiments have been carried out with a commercial medication containing ibuprofen ((RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid) which has been submitted to prolonged milling up to 40 h. When Al(OH)₃ is used as co-reagent, the first degradation step induced by the mechanochemical treatment is an acid-base reaction with the ibuprofen carboxylic acid group. The subsequent degradation follows a complex pathway leading to 1-(4-isobutylphenyl)ethanone, 1-isobutyl-4-vinylbenzene and 2-(4-(3-methylbutan-2-yl)phenyl)propan-1-ol after 10 h milling and, in addition, 1-(4-acetylphenyl)-2-methylpropan-1-one, 1-(4-(1-hydroxy-2-methylpropyl)phenyl)ethanone and 1-(4-(2-hydroxy-2-methylpropyl)phenyl)ethanone after 40 h milling. The degradation reaction path and products have been identified by means of FT-IR spectroscopy, thin layer chromatography, NMR spectroscopy, mass spectroscopy and elemental analysis. The observed ibuprofen decarboxylation makes the drug simultaneously lose both its pharmaceutical activity and toxicity.     

Transport infrastructures,environment impacts and tourists' welfare: a choice experiment to elicit tourist preferences in Siena–Italy

Transport infrastructures have been investigated as drivers of tourist demand. Specific attention has been devoted to air transport infrastructure and services. However, the literature on this issue is scanty. Moreover, few studies focus on ex-ante valuation of tourists' preferences for mobility systems. This study contributes to this literature by presenting a case study on the re-organization of the mobility system to access the city of Siena, Italy. A choice experiment is carried out to elicit tourists' preferences for distance, time, cost, travel mode, along with the environmental impact of infrastructure. The latter factor turns out to be particularly relevant in explaining tourists' choices and welfare. Furthermore, the results appear to be robust and not significantly dependent on design settings (specifically the number of alternatives). While these results only refer to a single case study, they seem to suggest that new transportation facilities do not necessarily cause an increase in tourism flows.     

TENORM employed as inert material for house building: a model for evaluating the radon activity enhancement

Environmental Science and Pollution Research - Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when...