The contexts of knowing: natural history of a globally distributed team

The focus of this paper is cognitive convergence in a globally distributed team (GDT), defined as the process by which cognitive structures of distributed team members gradually become more similar over time. To explore the convergence process, we employed a longitudinal, ethnographic research strategy that allowed us to follow a naturally occurring GDT over a 14‐month period, producing a rich case study portraying factors and processes that influence convergence. Confirming previous studies, we find that increases in shared cognition alone are not sufficient to account for performance gains on a GDT. Rather, it may be necessary not only to increase the sharing of cognition, but also to reverse a pattern of increasing divergence that can result from rejection of key knowledge domains. We also found that several factors influence the process of cognitive convergence beyond direct knowledge sharing. These include: separate but parallel or similar learning experiences in a common context; the surfacing of hidden knowledge at remote sites by third‐party mediators or knowledge brokers; and shifts in agent self‐interest that motivate collaboration and trigger the negotiation of task interdependence. Also relevant to cognitive convergence on a GDT is the geographical distribution pattern of people and resources on the ground, and the different ways in which leaders exploit the historical, cultural and linguistic dimensions of such distribution to further their own political agendas. Several propositions related to these observations are suggested. We conclude that GDTs can be effective in bringing together divergent points of view to yield new organizational capabilities, but such benefits require that leaders and members recognize early and explicitly the existence and validity of their differences. Copyright © 2004 John Wiley & Sons, Ltd.     

The perceived compatibility of safety and production expectations in hazardous occupations

INTRODUCTION: Safety hazards are unavoidable in many work environments. Employees must be both productive and safe, however, conflicting safety and production demands can negatively affect safety, production, or both. The employee's perception of the compatibility of management's safety and production expectations is a possible predictor of such consequences. This paper defines "safety-production compatibility" and describes how measures of safety-production compatibility, as well as safety pressure and production pressure, were developed. METHOD: We used LISREL structural equation modeling to test the influences of safety-production compatibility, safety pressure, and production pressure on safe work behavior and interference with performing other work tasks. The 239 study participants were workers employed in diverse but hazardous occupations. RESULTS: Pressure to work safely was positively associated with safe work behavior. The perceived compatibility of safety and production demands positively influenced safe work behavior and reduced the interference of safety hazards performing other tasks. Safety-production compatibility was also found to mediate the relationship between trust in management and safe work behavior. CONCLUSIONS: The results of this field study suggest increased compatibility, and thus less conflict, between safety and production demands influences safe work behavior and the interference of safety hazards with performing other work tasks. More broadly, the worker's reaction to multiple work demands is a safety and performance influence. IMPACT ON INDUSTRY: Safety management efforts that focus only on the hazards fail to eliminate many accidents because accidents arise from many factors including technology, safety climate, social influences, production, and safety demands. This study suggests that workers differ in their perception of the compatibility of safety and production demands. These differences will show up in safe work behavior, influencing the effectiveness of safety management efforts and the trust workers have in management's concern for safety.     

Distribution of foraging habitats of male loggerhead turtles (Caretta caretta) as revealed by stable isotopes and satellite telemetry

Most studies on the foraging ecology of loggerhead turtles (Caretta caretta) have focused on adult females and juveniles. Little is known about the foraging patterns of adult male loggerheads. We analyzed tissues for carbon and nitrogen stable isotopes (δ¹³C and δ¹⁵N) from 29 adult male loggerheads tracked with satellite transmitters from one breeding area in Florida, USA, to evaluate their foraging habitats in the Northwest Atlantic (NWA). Our study revealed large variations in δ¹³C and δ¹⁵N and a correlation between both δ¹³C and δ¹⁵N and the latitude to which the loggerheads traveled after the mating season, thus reflecting a geographic pattern in the isotopic signatures. Variation in δ¹³C and δ¹⁵N can be explained by differences in food web baseline isotopic signatures rather than differences in loggerhead trophic levels. Stable isotope analysis may help elucidate residency and migration patterns and identify foraging sea turtle subpopulations in the NWA due to the isotopically distinct habitats used by these highly migratory organisms.     

Molecular phylogenies help resolve taxonomic confusion with Asian <Emphasis Type="Italic">Crassostrea</Emphasis> oyster species

Identification of oyster species is still largely based on phenotypic characters that are highly plastic. Prompted by the proposed introduction of the Asian oyster species Crassostrea ariakensis into the Chesapeake Bay region of the U.S.A., this study uses molecular genetic information to understand the taxonomic framework surrounding C. ariakensis and to confidently distinguish among various sympatric oyster species. Putative samples of C. ariakensis and other species of cupped oysters from across Asia were collected and phylogenetic analyses were conducted on DNA sequences of both nuclear (ITS-1) and mitochondrial (COI) regions. Trees generated based on the two independent molecular datasets were highly congruent, and indicate that many oysters collected for this study as C. ariakensis were originally misidentified. Results also indicate that C. ariakensis, C. hongkongensis and C. nippona are distinct, but closely related species. There is strong support in both analyses for a close relationship between C. gigas and C. sikamea, as well as between C. belcheri and C. gryphoides, and between C. iredalei and C. madrasensis. The parsimony analyses based on these DNA markers, however, did not provide evidence to support C. angulata as a distinct species from C. gigas. Overall, the results emphasize the need for rigorous species identification, and additional extensive and intensive sampling to more accurately determine relationships among Crassostrea species, define their geographic distributions, and establish existing sympatry patterns.     

Effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the affected area. The chemical changes caused by the red mud leachate and the effects of these changes on living organisms were assessed. Ecotoxicological tests were performed with Vibrio fischeri, Sinapis alba and Folsomia candida and the number of aerobic heterotrophic microorganisms was determined. The total, plant-available, exchangeable and water-soluble fractions of Na, Mo, Cu and Cr increased in the soil, mostly owing to their leaching from the red mud layer, but partly to the increase in the pH and DOC concentration. The chemical changes only had significant effects on the test organisms in the 0–30 cm soil layer, except for F. candida, which also had a lower survival rate in the 30–50 cm soil layer. No severe toxic effects were detected in the test organisms; in fact a stimulating effect was revealed for the aerobic heterotrophic cell number and for S. alba germination. However, the red mud itself was toxic, so the ecotoxicological tests justified the removal of red mud from the soil surface after the disaster.     

Network structure and prevalence of Cryptosporidium in Belding’s ground squirrels

Although pathogen transmission dynamics are profoundly affected by population social and spatial structure, few studies have empirically demonstrated the population-level implications of such structure in wildlife. In particular, epidemiological models predict that the extent to which contact patterns are clustered decreases a pathogen’s ability to spread throughout an entire population, but this effect has yet to be demonstrated in a natural population. Here, we use network analysis to examine patterns of transmission of an environmentally transmitted parasite, Cryptosporidium spp., in Belding’s ground squirrels (Spermophilus beldingi). We found that the prevalence of Cryptosporidium was negatively correlated with transitivity, a measure of network clustering, and positively correlated with the percentage of juvenile males. Additionally, network transitivity decreased when there were higher percentages of juvenile males; the exploratory behavior demonstrated by juvenile males may have altered the structure of the network by reducing clustering, and low clustering was associated with high prevalence. We suggest that juvenile males are critical in mediating the ability of Cryptosporidium to spread through colonies, and thus may function as “super-spreaders.” Our results demonstrate the utility of a network approach in quantifying mechanistically how differences in contact patterns may lead to system-level differences in infection patterns.     

Salmonella survival in manure-treated soils during simulated seasonal temperature exposure

Addition of animal manure to soil can provide opportunity for Salmonella contamination of soil, water, and food. This study examined how exposure of hog manure-treated loamy sand and clay soils to different simulated seasonal temperature sequences influenced the length of Salmonella survival. A six-strain cocktail of Salmonella serovars (Agona, Hadar, Heidelberg, Montevideo, Oranienburg, and Typhimurium) was added to yield 5 log cfu/g directly to about 5 kg of the two soils and moisture adjusted to 60 or 80% of field capacity (FC). Similarly, the Salmonella cocktail was mixed with fresh manure slurry from a hog nursery barn and the latter added to the two soils at 25 g/kg to achieve 5 log cfu/g Salmonella. Manure was mixed either throughout the soil or with the top kilogram of soil and the entire soil volume was adjusted to 60 or 80% FC. Soil treatments were stored 180 d at temperature sequences representing winter to summer (-18, 4, 10, 25 degrees C), spring to summer (4, 10, 25, 30 degrees C), or summer to winter (25, 10, 4, -18 degrees C) seasonal periods with each temperature step lasting 45 d. Samples for Salmonella recovery by direct plating or enrichment were taken at 0, 7, and 15 d post-inoculation and thereafter at 15-d intervals to 180 d. Salmonella numbers decreased during application to soil and the largest decreases occurred within the first week. Higher soil moisture, manure addition, and storage in the clay soil increased Salmonella survival. Salmonella survived longest (> or = 180 d) in both soils during summer-winter exposure but was not isolated after 160 d from loamy sand soil exposed to other seasonal treatments. For all but one treatment decimal reduction time (DRT45d) values calculated from the first 45 d after application were < or = 30 d and suggested that a 30-d delay between field application of manure in the spring or fall and use of the land would provide reasonable assurance that crop and animal contamination by Salmonella would be minimized.     

Urban Streamflow Response to Imported Water and Water Conservation Policies in Los Angeles,California

Los Angeles has a long history of importing water; however, drought, climate change, and environmental mitigation have forced the City to focus on developing more local water sources (target of 50% local supply by 2035). This study aims to improve understanding of water cycling in Los Angeles, including the impacts of imported water and water conservation policies. We evaluate the influence of local water restrictions on discharge records for 12 years in the Ballona Creek (urban) and Topanga Creek (natural) watersheds. Results show imported water has significantly altered the timing and volume of streamflow in the urban Ballona watershed, resulting in runoff ratios above one (more streamflow than precipitation). Further analysis comparing pre‐ vs. during‐mandatory water conservation periods shows there is a significant decrease in dry season streamflow during‐conservation in Ballona, indicating that prior to conservation efforts, heavy irrigation and other outdoor water use practices were contributing to streamflow. The difference between summer streamflow pre‐ vs. during‐conservation is enough to serve 160,000 customers in Los Angeles. If Los Angeles returns to more watering days, educating the public on proper irrigation rates is critical for ensuring efficient irrigation and conserving water; however, if water restrictions remain in place, the City must take the new flow volumes into account for complying with water quality standards in the region.     

Determination of cytotoxicity of nephrotoxins on murine and human kidney cell lines

The present study investigates renal inner medullary collecting duct (mIMCD3) cells and human embryonic kidney cells (HEK293) for evaluation of cytotoxicity of nephrotoxic compounds. The 24 h LC(50) values for cisplatin, paraquat and ibuprofen in mIMCD3 cells were 135, 155 and 3600 microM, respectively. The 24 h LC(50) values for paraquat and ibuprofen in HEK293 cells were 180 and 1000 microM, respectively. Effects of hyperosmolality on cytotoxicity of paraquat were additive in mIMCD3 cells. These data demonstrate that renal hyperosmolality has an additive effect on cytoxicity of paraquat.     

Fog Chemistry at an Urban Midwestern Site

This work investigates the oxidative aging of preformed secondary organic aerosol (SOA) derived from α-pinene ozonolysis (～100 ppb_v hydrocarbon [HC_x] with excess of O₃) within the University of California–Riverside Center for Environmental Research and Technology environmental chamber that occurs after introduction of additional hydroxyl (OH) and nitrate (NO₃) radicals. Simultaneous measurements of SOA volume concentration, hygroscopicity, particle density, and elemental chemical composition (C:O:H) reveal increased particle wall-loss-corrected SOA formation (1.5%, 7.5%, and 15.1%), increase in oxygen-to-carbon ratio (O/C; 15.6%, 8.7%, and 8.7%), and hydrophilicity (4.2%, 7.4%, and 1.4%) after addition of NO (ultraviolet [UV] on), H₂O₂ (UV on), and N₂O₅ (dark), respectively. The processing observed as an increase in O/C and hydrophilicity is attributed to OH and NO₃ reactions with first-generation vapor products and UV photolysis. The rate of increase in O/C appears to be only sufficient to achieve semivolatile oxygenated organic aerosol (SV-OOA) on a day time scale even at the raised chamber radical concentrations. The additional processing with UV irradiation without addition of NO, H₂O₂, or N₂O₅ is observed, adding 5.5% wall-loss-corrected volume. The photolysis-only processing is attributed to additional OH generated from photolysis of the nitrous acid (HONO) offgasing from chamber walls. This finding indicates that OH and NO₃ radicals can further alter the chemical composition of SOA from α-pinene ozonolysis, which is proved to consist of first-generation products.

Implications: Secondary organic aerosol (SOA) may undergo aging processes once formed in the atmosphere, thereby altering the physicochemical and toxic properties of aerosol. This study discusses SOA aging of a major biogenic volatile organic compound (VOC; α-pinene) after it initially forms SOA. Aging of the α-pinene ozonolysis system by OH (through NO or H₂O₂ injection), NO₃ (through N₂O₅ injection), and photolysis is observed. Although the reaction rate appears to be only sufficient to achieve semivolatile oxygenated organic aerosol (SV-OOA) level of oxygenation on a 1-day scale, it is important that SOA aging be considered in ambient air quality models. Aging in this study is attributed to further oxidation of gas-phase oxidation products of α-pinene ozonolysis.

Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air &; Waste Management Association for information on the referenced α-pinene ozonolysis reaction and chamber reactor temperature.