Characterization of the archaeal community fouling a membrane bioreactor

Biofilmformation, one of the primary causes of biofouling, results in reducedmembrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor (MBR) technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilmthan the sludge during the establishment of biofilms at low transmembrane pressure (TMP). Clustering of the communities based on the Bray-Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata, Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP.     

Work—nonwork conflict and the perceived quality of life

From additive models of overall quality of life, two hypotheses were derived about the relationships among work—family conflict, work—leisure conflict, job satisfaction, family satisfaction, leisure satisfaction and global life satisfaction. In supporting these two hypotheses, path analyses of survey data from a national probability sample of United States workers (n = 823) showed: (1) the direct paths between work—nonwork conflict and global life satisfaction were nonsignificant; and (2) the indirect paths between work—nonwork conflict and global life satisfaction, which are mediated by job satisfaction and nonwork satisfaction, were all significant. Further analyses indicated that, in general, the magnitude of these path coefficients was not significantly moderated by sociodemographic variables. Discussion considered the role of additive models as conceptual frameworks for studies concerned with the effects of work experiences on the overall quality of life.     

Management Implications of Snowpack Sensitivity to Temperature and Atmospheric Moisture Changes in Yosemite National Park,CA

In order to investigate snowpack sensitivity to temperature increases and end‐member atmospheric moisture conditions, we applied a well‐constrained energy‐ and mass‐balance snow model across the full elevation range of seasonal snowpack using forcing data from recent wet and dry years. Humidity scenarios examined were constant relative humidity (high) and constant vapor pressure between storms (low). With minimum calibration, model results captured the observed magnitude and timing of snowmelt. April 1 snow water equivalent (SWE) losses of 38%, 73%, and 90% with temperature increases of 2, 4, and 6°C in a dry year centered on areas of greatest SWE accumulation. Each 2°C increment of warming also resulted in seasonal snowline moving upslope by 300 m. The zone of maximum melt was compressed upward 100–500 m with 6°C warming, with the range reflecting differences in basin hypsometry. Melt contribution by elevations below 2,000 m disappeared with 4°C warming. The constant‐relative‐humidity scenario resulted in 0–100 mm less snowpack in late spring vs. the constant‐vapor‐pressure scenario in a wet year, a difference driven by increased thermal radiation (+1.2 W/m²) and turbulent energy fluxes (+1.2 W/m²) to the snowpack for the constant‐relative‐humidity case. Loss of snowpack storage and potential increases in forest evapotranspiration due to warming will result in a substantial shift in forest water balance and present major challenges to land management in this mountainous region.     

A new approach to propellant formulation: minimizing life-cycle costs through science-based design

The traditional approach to developing propellants for specific gun applications relies heavily on trial and error. Candidate formulations must be made in small quantities and subjected to burning-rate measurements and small-scale vulnerability assessments. If the properties of these candidates fail to meet expectations, the process must be repeated. This approach, while historically unavoidable, is obviously inefficient in time and expense, but it also can generate considerable waste streams associated with unsuccessful formulations. With added considerations of life-cycle costs including environmental impact at all stages of development, use, and disposal, this traditional approach becomes increasingly unworkable. In this report a new approach is proposed which makes maximal use of scientific understanding embodied in models during the early phases of the propellant-development cycle. Through simple simulations, it is shown that this strategy can have a significant impact on the overall costs of the development process. In analogy to the DOE program to convert the nuclear-weapon stewardship from testing-based to science-based, we term the new approach "science-based design." It is argued that the modeling contribution to the propellant-development process is most efficiently implemented by subjecting candidate formulations to a hierarchy of models of different sophistication and input-data requirements, reserving the most rigorous models (usually the most data-intensive and least robust) for the most promising candidates. This new approach will require concentration and leveraging of resources toward the most critical early-phase development steps, but it may be the only credible strategy to reconcile the need for higher-performance weapons with the reality of declining resources.     

Science and Decision Making: Water Management and Tree‐Ring Data in the Western United States1

Abstract: Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prompting some water managers to seek out and utilize new forms of climate data in their planning efforts. One source of information that is now being considered by water resource management is extended hydrologic records from tree‐ring data. Scientists with the Western Water Assessment (WWA) have been providing reconstructions of streamflow (i.e., paleoclimate data) to water managers in Colorado and other western states (Arizona, New Mexico, and Wyoming), and presenting technical workshops explaining the applications of tree‐ring data for water management for the past eight years. Little is known, however, about what has resulted from these engagements between scientists and water managers. Using in‐depth interviews and a survey questionnaire, we attempt to address this lack of information by examining the outcomes of the interactions between WWA scientists and western water managers to better understand how paleoclimate data has been translated to water resource management. This assessment includes an analysis of what prompts water managers to seek out tree‐ring data, how paleoclimate data are utilized by water managers in both quantitative and qualitative ways, and how tree‐ring data are interpreted in the context of organization mandates and histories. We situate this study within a framework that examines the coproduction of science and policy, where scientists and resource managers collectively define and examine research and planning needs, the activities of which are embedded within wider social and political contexts. These findings have broader applications for understanding science‐policy interactions related to climate and climate change in resource management, and point to the potential benefits of reflexive interactions of scientists and decision makers.     

水稻重金属污染研究进展

从水稻植株和籽实对重金属的吸收富集规律、重金属的分析方法、重金属的赋存形态、受重金属污染后水稻的生理生化效应等四个方面，介绍了水稻中重金属污染的研究进展，并对今后控制水稻受重金属污染的方向提了一些建议。     

Significance of active and passive depuration in the clearance of naphthalene from the tissues of Hemigrapsus nudus (Crustacea: Decapoda)

Photosynthate incorporation into lipids, low molecular weight compounds, polysaccharides and proteins by individual phytoplankton species isolated from natural populations is described. This sensitive method uses serial solvent extraction and liquid scintillation counting and gives results indentical to those obtained from filtering large numbers of cells from suspension. The time course of incorporation of ¹⁴C into these polymers for algae isolated from estuarine and coastal populations shows (i) considerable differences in the carbon metabolism among species, (ii) the pattern of incorporation by any individual species may not reflect that of the phytoplankton community and (iii) significant reallocation of cell carbon among carbon pools and net protein synthesis at night. This technique permits the in-situ carbon metabolism of individual species to be examined.     

Biocultural diversity in traditional rice-based agroecosystems: indigenous research and conservation of mavo (Oryza sativa L.) upland rice landraces of eastern Indonesia

Traditional crop landraces play dynamic roles in the expression of native biological and cultural diversity via their central position in the genetic resource base, agroecosystems and social heritage of indigenous peoples. Farmer varieties provide farmers with an “agricultural survival kit” for household welfare and for adaptation to changing conditions. These varieties meet local cultural practices and environmental constraints, and play an intrinsic role in cultural survival by constituting a living repository of ancestral customs including cultivar-specific recipes, songs, handicrafts, stories of origin, and unique planting, harvesting, processing, and storage rituals and techniques. The centrality of rice in Southeast Asian agricultural and social systems, contrasted with the significant erosion of rice-based biological and cultural diversity in native communities, calls for increased attention to the links between traditional rice varieties and indigenous rice-based customs. This study represents the research efforts of rice farmers pertaining to the Tado clan, a Kempo Manggarai community on Flores␣Island, in association with USA academicians. Research results demonstrate: (i) a complex suite of upland rice-based ethnobotanical traditions; (ii) significant and␣dynamic regional flux and dissemination of “old” and “new” landraces; (iii)␣community-level maintenance of distinct genotypes across a range of microenvironments; (iv) localized “extinctions” of ancestral landraces within 1–2 generations and a concomitant loss of related traditions; and (v) the contributions of a collaborative (indigenous and academic) approach to ethnographic and agronomic research.     

Effects of the California graduated driver licensing program

PROBLEM: On July 1, 1998, in an effort to ameliorate the problem of high teenage driver crash rates, California implemented a graduated driver licensing system (GDLS). METHOD: Data on injury crashes of 16- and 17-year-old drivers from a pre-GDLS year were compared with data from two post-GDLS years. Per-capita crash rate ratios were adjusted for changes in crash rates of 25- to 34-year-old drivers, who were unaffected by the GDLS. Prevented numbers and 95% confidence intervals were estimated. RESULTS: Fatal or severe injury crash rates were significantly lower during each of the two post-GDLS years (adjusted rate ratios (RR)=0.72 and 0.83, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Significant rate reductions were observed for all crash types, particularly for struck object (RR=0.71 and 0.80, for 2000 vs. 1997 and 2001 vs. 1997, respectively) and non-collision (RR=0.63 and 0.72, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Minor injury crash rates were also lower during post-GDLS years (RR=0.87 and 0.90, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Percent reductions were notably larger during the hours of the late night driving restriction (midnight-5 a.m.) (RR=0.79 and 0.87, for 2000 vs. 1997 and 2001 vs. 1997, respectively). SUMMARY: The implementation of the California GDLS was followed by large reductions in the rate of injury-producing motor-vehicle crashes. IMPACT ON INDUSTRY: This evaluation supports previous evidence that GDLS is an effective countermeasure to adolescent motor-vehicle crashes and their associated injuries. States with a traditional licensing system may prevent adolescent driver crashes by adopting a GDLS. Future studies should examine factors that influence teenager compliance with GDLS provisions and identify approaches to improving compliance.     

Influence of simulated tidal cycles on aromatic hydrocarbon uptake and elimination by the shore crab Hemigrapsus nudus

Specimens of the intertidal crab Hemigrapsus nudus (Dana, 1851) were collected near Sitka, Alaska, in 1983, and were used in laboratory experiments to determine the influence of periodic exposure to air on the toxicity, uptake, and elimination of two aromatic hydrocarbons, toluene and naphthalene. Three tidal cycles were simulated; i.e., crabs spent 0, 33, or 66% of the time in air and the remainder of the time in toxicant or seawater solutions. Naphthalene was 10 to 20 times more toxic than toluene: naphthalene caused locomotory impairment or killed the crabs more rapidly and at concentrations lower than those of toluene. In tissues, naphthalene was accumulated faster and to higher concentrations than was toluene. Exposure to air 66% of the time reduced mortality as well as the rate at which toluene and naphthalene were accumulated and lost. Crabs exposed to air had significantly higher respiration rates than those submerged in seawater; thus, reduced rates of accumulation and loss of hydrocarbons were not caused by general metabolic quiescence. Exposure to air reduced the time the crabs were in contact with water-borne hydrocarbons and, therefore, reduced toxicity of the hydrocarbons. Once crabs had accumulated the toxicants, however, elimination was hindered by exposure to air, even for the somewhat volatile compound toluene.