Effect of the environment on the risk of respiratory disease in preweaning dairy calves during summer months

Heat stress has the potential to adversely affect the physiology, passive immunity, and growth of preweaning dairy calves, increasing their risk of respiratory disease. The effect of heat stress on the risk for bovine respiratory disease (BRD) may be mediated in part through housing, ventilation, and management factors. As a result, differences may exist in meteorological measures recorded in the calf-rearing area (macroenvironment) and within a calf's enclosure (microenvironment). The objective of this prospective cohort study was to evaluate and compare the association between exposure to temperature and humidity measured at the macro- and microenvironment, and BRD in preweaning dairy calves; a secondary objective was to evaluate the correlation between the macro- and microenvironment. A cohort of 252 calves from 4 premises in central San Joaquin Valley, California (CA), was followed and evaluated for development of respiratory disease using the CA BRD scoring system for preweaning dairy calves, a standardized and validated scoring system. During this time, the meteorological conditions of the calf-rearing area and the within-hutch environment were measured and showed a significant correlation with regard to temperature and humidity. Mixed effects logistic regression and survival analysis were used to analyze the association between the exposures daily environmental measures of temperature, humidity, and temperature-humidity index (THI) and the outcome BRD, adjusted for dairy premises, calf age, sex, and breed. Results showed a significant positive association between daily maximum temperature and BRD in both the calf's macroenvironment [odds ratio = 1.121 (95% confidence interval (CI) = 1.029–1.222)] and microenvironment [odds ratio = 1.203 (95% CI = 1.020–1.418)]. Estimated hazard rates also showed a significant positive association between BRD and daily maximum temperature in both the macroenvironment [hazard ratio = 1.127 (95% CI = 1.053–1.206)] and microenvironment [hazard ratio = 1.119 (95% CI = 1.047–1.197)]. In contrast, we found no association between daily maximum humidity in a calf's microenvironment and BRD. Daily maximum THI within the hutch was significantly associated with only the rate of BRD cases [hazard ratio = 1.070 (95% CI = 1.003–1,141)] but not the odds of occurrence of BRD. Maximum THI is estimated using temperature and humidity, which in California's hot and dry summers may limit variability in THI, explaining its weaker significant association with risk of BRD (or lack of association with odds of BRD) compared with models for maximum temperature in this study. Calves exposed to high day temperatures and relatively low humidity may be experiencing heat stress that predisposes to BRD. Results of the current study suggest that heat abatement efforts should address heat stress at the microenvironment level to mitigate BRD in calves. Further research should investigate strategies to improve calf hutch systems, including hutch materials and design that may optimize ventilation, provide ample shade, spacing, cleanliness, and protection from heat.     

Reactivity and chemical characterization of effluent organic nitrogen from wastewater treatment plants determined by Fourier transform ion cyclotron resonance mass spectrometry

In advanced wastewater treatment plants that achieve high levels of nitrogen (N) removal, up to one-third of the N in effluent is organic, herein referred to as effluent organic N (EON). While we know that inorganic N is highly labile, it is unclear what fraction of EON is bioavailable. In this study, we demonstrate the utility of a method that can be used to examine the reactivity of EON in natural receiving waters to better understand both the ecosystem response and the potential bioavailability of EON. The technique is suitable for analyzing polar organic matter in natural waters; electrospray ionization coupled with Fourier transform mass spectrometry. Bioassays were performed on samples collected at the end of the biological process from two wastewater treatment plants achieving advanced N removal. The samples were concentrated, and then added to natural water samples collected from the oligohaline James River, a major tributary of the Chesapeake Bay. Our results demonstrate that while the lignin-like fraction of the effluent dissolved organic matter (some of which contains N) was conserved, a large portion of aliphatic and aromatic compounds containing N was removed (79-100%) during incubations, while other compounds were produced. Furthermore, the two effluents exhibited differences in the degree of degradation and type of degradation, which can be related both to the various processes employed in the two WWTPs and the dramatic differences in the type of influent they received. These findings suggest that EON is highly reactive in the natural environment and that simple assays examining net consumption or production of bulk dissolved organic N pools are inadequate for assessing the bioavailability of EON.     

Enhanced biodegradation of carbamazepine after UV/H2O2 advanced oxidation

Carbamazepine is one of the most persistent pharmaceutical compounds in wastewater effluents due to its resistance to biodegradation-based conventional treatment. Advanced oxidation can efficiently degrade carbamazepine, but the toxicity and persistence of the oxidation products may be more relevant than the parent. This study sets out to determine whether the products of advanced oxidation of carbamazepine can be biotransformed and ultimately mineralized by developing a novel methodology to assess these sequential treatment processes. The methodology traces the transformation products of the (14)C-labeled carbamazepine during UV/hydrogen peroxide advanced oxidation and subsequent biotransformation by mixed, undefined cultures using liquid scintillation counting and liquid chromatography with radioactivity, mass spectrometry, and UV detectors. The results show that the oxidation byproducts of carbamazepine containing a hydroxyl or carbonyl group can be fully mineralized by a mixed bacterial inoculum. A tertiary treatment approach that includes oxidation and biotransformation has the potential to synergistically mineralize persistent pharmaceutical compounds in wastewater treatment plant effluents. The methodology developed for this study can be applied to assess the mineralization potential of other persistent organic contaminants.     

A Particle Adhesion Perspective on Metastasis

One area of interest in bioadhesion that has not been emphasized within the adhesion science community relates to the disaggregation of cells which occurs when cancer metastases arise. Metastasis involves the distribution of cancerous tumor cells from a large localized tumor. The resulting spatial separation of the cancerous masses makes treatment more difficult. Making use of biochemical and cellular assays, detailed mechanisms for the cell detachment processes involving cadherin cell adhesion molecules have been proposed. This paper reviews proposed mechanisms for metastasis from a cellular adhesion perspective and the testing methodologies that have been utilized. Additional understanding might be gleaned from considering the loss of cell adhesion molecules and the overall disaggregation process from a particle adhesion perspective. Several pertinent theories are presented as well as a brief discussion of areas for future effort.     

Establishment of Critical Success Factors for Construction Partnering

Research into the use of partnering in construction has become ubiquitous; however, a framework is needed that can be used to identify critical success factors (CSFs) that contribute to the successful use of partnering in projects. Based on a review of the partnering literature within the management discipline, a partnering framework has been developed to identify the CSFs for construction parties implementing partnering arrangements. The framework highlights the influence of contextual characteristics and management skills on partnering success. The CSFs identified and discussed in the framework are effective communication, conflict resolution, adequate resources, management support, mutual trust, long-term commitment, coordination, and creativity. The degree of success of partnering can be determined by subjective measures (e.g., perceived satisfaction of partners' expectations) and objective measures (e.g., cost variation and rejection of work). A case for initiating partnering is also presented, together with some general guidelines.     

Architectures for molecular electronic computers. I. Logicstructures and an adder designed from molecular electronic diodes

Recently, there have been significant advances in the fabrication and demonstration of individual molecular electronic wires and diode switches. This paper reviews those developments and shows how demonstrated molecular devices might be combined to design molecular-scale electronic digital computer logic. The design for the demonstrated rectifying molecular diode switches is refined and made more compatible with the demonstrated wires through the introduction of intramolecular dopant groups chemically bonded to modified molecular wires. Quantum mechanical calculations are performed to characterize some of the electrical properties of the proposed molecular diode switches. Explicit structural designs are displayed for AND, OR, and XOR gates that are built from molecular wires and molecular diode switches. The diode-based molecular electronic logic gates are combined to produce a design for a molecular-scale electronic half adder and a molecular-scale electronic full adder. These designs correspond to conductive monomolecular circuit structures that would be one million times smaller in area than the corresponding micron-scale digital logic circuits fabricated on conventional solid-state semiconductor computer chips. It appears likely that these nanometer-scale molecular electronic logic circuits could be fabricated and tested in the foreseeable future. At the very least, such molecular circuit designs constitute an exploration of the ultimate limits of electronic computer circuit miniaturization     

Divergence or Congruence? A Path Model of Rework for Building and Civil Engineering Projects

Rework has been identified as a major contributor to cost and schedule overrun in construction projects. Previous studies that have examined rework are based on a limited data sets and thus eschew generalizations being made about the key determinants. Using data from 260 completed building (n = 147) and civil engineering (n = 113) projects, path analysis is used to develop a structural model of the most significant causes of rework. The model revealed that the paths of client-directed changes, site management and subcontractors, and project communication were statistically significant contributors to rework costs. The analysis confirmed that the lack of attention to quality management resulted in higher rework costs being incurred in the projects sampled. The analysis also revealed that there were no significant differences between building and civil engineering projects in terms of the direct and indirect cost of rework experienced, and the effectiveness of the project management practices implemented. Considering the findings, it is suggested that generic strategies for reducing the incidence rework in construction and civil engineering projects can be developed.     

Risk assessment in the maintenance of offshore caisson operations

Undertaking maintenance of offshore caissons is a pervasive challenge that involves an array of risks and uncertainties. Despite the adoption of standardised and routine maintenance procedures that are subject to on-going improvements, the rate of failure in offshore caissons remains relatively high. To manage the effect of risk and uncertainties associated with the maintenance of offshore caissons, expert judgment can be drawn upon to better understand and capture the issues that contribute to their failure. Using a case study of an offshore hydrocarbon discharge caisson in the North Sea of the United Kingdom, expert judgements from industry practitioners are obtained using the Delphi Interview and Analytic Hierarchy Process (AHP) technique to rank 14 possible recovery options. Sensitivity analysis is used to ascertain the suitability of each of the options. Results reveal that the Delphi technique employed provided a robust means to garner invaluable insights from experts about the issues associated with caisson failure. The corollary is the development of a framework that serves as a point of reference to identify and assess the risks in offshore caisson maintenance operations. This framework can also be used in conjunction with existing probabilistic methods to improve the effectiveness of decision-making during operations and maintenance.