HPLC determination of chlorate metabolism in bovine ruminal fluid

Salmonella and Escherichia coli are two bacteria that are important causes of human and animal disease worldwide. Chlorate is converted in the cell to chlorite, which is lethal to these bacteria. An HPLC procedure was developed for the rapid analysis of chlorate (ClO(3)(-)), nitrate (NO(3)(-)), and nitrite (NO(2)(-)) ions in bovine ruminal fluid samples. Standard curves for chlorite, nitrite, nitrate, and chlorate were well defined linear curves with R(2) values of 0.99846, 0.99106, 0.99854, and 0.99138, respectively. Concentrations of chlorite could not be accurately determined in bovine ruminal fluid because chlorite reacts with or binds a component(s) or is reduced to chloride in bovine ruminal fluid resulting in low chlorite measurements. A standard curve ranging from 25 to 150 ppm ClO(3)(-) ion was used to measure chlorate fortified into ruminal fluid. The concentration of chlorate was more rapidly lowered (P < 0.01) under anaerobic compared to aerobic incubation conditions. Chlorate alone or chlorate supplemented with the reductants sodium lactate or glycerol were bactericidal in anaerobic incubations. In anaerobic culture, the addition of sodium formate to chlorate-fortified ruminal fluid appeared to decrease chlorate concentrations; however, formate also appeared to moderate the bactericidal effect of chlorate against E. coli. Addition of the reductants, glycerol or lactate, to chlorate-fortified ruminal fluid did not increase the killing of E. coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production.     

Undue concentration of research and education: multi-criteria decision approach to assess jurisdiction eligibility for NSF funding

Research and education tend to concentrate in specific geographical areas, while many jurisdictions receive limited federal research funding. This has resulted in reduced opportunity for students as well as limited ability of science to influence solving problems at the jurisdiction level. The National Science Foundation’s Experimental Program to Stimulate Competitive Research (EPSCoR) was intended to address the “undue concentration of research and education” by providing direct funding to improve research infrastructure, hire researchers, develop outreach, and to enhance local research capacity. Despite many successful outcomes attributed to EPSCoR, the aim and the execution of the program have generated controversy. Decision analytic tools can provide a systematic approach to EPSCoR prioritization that improves transparency and addresses the program’s intent. The wording of NSF’s mission and EPSCoR legislation suggest the intent of maximizing NSF’s benefit to the nation by directly supporting scientific research product across all jurisdictions and by supporting development of competitive scientific capabilities within particular jurisdictions. These components may be quantified via data-driven metrics producing indicators of ultimate benefit. Using illustrative scenarios within a multi-criteria decision model, we explore how such decision models may generate insights and how their guidance compares with current eligibility determinations.     

Interspecific attractiveness of structures built by courting male fiddler crabs: experimental evidence of a sensory trap

Male fiddler crabs Uca musica sometimes build sand hoods and male Uca beebei sometimes build mud pillars next to their burrows to which they attract females for mating. Mate-searching females preferentially approach these structures and subsequently mate with structure builders. Here we show that the preference for structures is not species-specific and argue that it may not have evolved for mate choice. When not near burrows, many species of fiddler crabs approach and temporarily hide near objects, suggesting that hoods and pillars may attract females because they elicit this general predator-avoidance behavior. To test this sensory trap hypothesis we individually released female U. musica, U. beebei and Uca stenodactylus, a non-builder, in the center of a circular array of empty burrows to which we added hoods and pillars and then moved a model predator toward the females. All species ran to structures to escape the predator and the two builders preferred hoods. Next, we put hood replicas on male U. beebei burrows and pillar replicas on male U. musica burrows. When courted, females of both species preferentially approached hoods as they did when chased with a predator. However, males of both species with hoods did not have higher mating rates than males with pillars perhaps because hoods block more of a male's visual field so he sees and courts fewer females. Sexual selection may often favor male signals that attract females because they facilitate general orientation or navigation mechanisms that reduce predation risk in many contexts, including during mate search.     

Sand disposal of the painted ghost crab Ocypode gaudichaudii (Decapoda: Ocypodidae): A possible role in courtship

In 1991/1992, we studied the sand disposal behavior of the painted ghost crabs Ocypode gaudichaudii on the Pacific coast of Panamá. O. gaudichaudii either kick, dump or tamp sand they excavate from their burrows. Here we relate these three kinds of sand disposal to burrow structure and distribution, as well as to crab size and sex. Our objective was to determine whether tamping may be a male courtship signal. Burrows whose owners tamped sand were on average longer, deeper, and higher on the beach than were burrows whose owners kicked or dumped sand. Five burrow shapes were distinguished, with half-spiral and spiral shapes being most common among tamped burrows. All crabs excavated from tamped burrows were males. Tamped burrows peaked in abundance around full and new moons. These observations, together with what is known about mating and breeding behavior of other ghost crabs, suggest that tamping may be involved in O. gaudichaudii courtship.     

Waterborne and sediment toxicity of fluoxetine to select organisms

Ecological risk assessments of pharmaceuticals are currently difficult because little-to-no aquatic hazard and exposure information exists in the peer-reviewed literature for most therapeutics. Recently several studies have identified fluoxetine, a widely prescribed antidepressant, in municipal effluents. To evaluate the potential aquatic toxicity of fluoxetine, single species laboratory toxicity tests were performed to assess hazard to aquatic biota. Average LC(50) values for Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas were 0.756 (234 microg/l), 2.65 (820 microg/l), and 2.28 microM (705 microg/l), respectively. Pseudokirchneriella subcapitata growth and C. dubia fecundity were decreased by 0.044 (14 microg/l) and 0.72 microM (223 microg/l) fluoxetine treatments, respectively. Oryias latipes survival was not affected by fluoxteine exposure up to a concentration of 28.9 microM (8.9 mg/l). An LC(50) of 15.2 mg/kg was estimated for Chironomus tentans. Hyalella azteca survival was not affected up to 43 mg/kg fluoxetine sediment exposure. Growth lowest observed effect concentrations for C. tentans and H. azteca were 1.3 and 5.6 mg/kg, respectively. Our findings indicate that lowest measured fluoxetine effect levels are an order of magnitude higher than highest reported municipal effluent concentrations.     

APPLICATION OF THE BASINS DATABASE AND NPSM MODEL ON A SMALL OHIO WATERSHED1

ABSTRACT: The purpose of this study was to evaluate the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) watershed management system. BASINS data were used with the NPSM model to predict discharge and sediment concentrations at the outlet of a 103 km² Ohio watershed. It was concluded that the NPSM model should always be calibrated but only a few of the parameters provided with BASINS needed to be calibrated. For a three‐year study period, there was a 2 percent underestimation of discharge using area weighted precipitation values and a 25 percent overestimation using the single station data in BASINS. A comparison of observed and predicted monthly discharge resulted in an r² of 0.86 with area‐weighted precipitation and an r² of 0.74 with the single station data. Calibrating the model to substantially improve sediment predictions was unsuccessful and we concluded that a calibration period of one year was too short. For the three‐year study period, the r² for sediment was 0.36 with a slope of 0.37 and an intercept of 18.8 mg/l. The mean observed and predicted sediment concentrations were 27.1 mg/l and 22.6 mg/l, respectively.     

Relationship between protean career orientation and work–life balance: A resource perspective

Despite the commonly held belief that a protean career orientation (PCO) enables employees to achieve more balance in their lives, little is known about the relationship between PCO and work–life balance. Using two waves of data collection separated by 2.5 years, this study examined the relationship between PCO and work–life balance among a sample of 367 college‐educated employees in the United States. Analysis was conducted to empirically distinguish PCO from conceptually related constructs, and structural equation modeling was used to examine the process that explains the linkage between PCO and balance. We found that PCO was positively related to work–life balance. We also found support for the role of several resources (social capital, psychological capital, and perceived employability) that explain the relationship between PCO and balance. In particular, PCO was associated with extensive career planning activities that were related to the accumulation of three forms of career capital—human capital, social capital, and psychological capital. In turn, social capital and psychological capital were associated with high employability, which was related to greater work–life balance for individuals who take a whole‐life perspective on their careers. We discuss the theoretical and practical implications of the findings and provide suggestions for future research. Copyright © 2015 John Wiley & Sons, Ltd.     

INVOLVING WATERSHED STAKEHOLDERS: AN ISSUE ATTRIBUTE APPROACH TO DETERMINE WILLINGNESS AND NEED1

ABSTRACT: The development of effective solutions for addressing nonpoint source pollution on a watershed basis often involves watershed stakeholders. However, success in engaging stakeholders in collaborative decision making processes varies, as watershed managers are faced with the challenges inherent to finding the right process for the decisions needed and in successfully engaging stakeholders in that process. Two characteristics that may provide guidance for determining the appropriateness of applying a collaborative process to a watershed problem are the need to collaborate and the willingness of stakeholders to engage in a collaborative decision making process. By examining seven attributes of the issues confronted by stakeholders in a collaborative process, the consequences of these attributes on the need for collaboration and stakeholders' willingness to engage can be estimated. The issue attributes include: level of uncertainty, balance of information, risk, time horizon of effects, urgency of decision, distribution of effects, and clarity of problem. The issue attribute model was applied to two collaborative decision making processes conducted by the same watershed stakeholder group in a North Carolina coastal watershed. Need and willingness to engage did not coincide for either issue; that is, stakeholders were more willing to engage on the issue that required less need for their involvement.