2,873 research outputs found
The Effects of Herbicides on Three Soil Inhabiting Blue Green Algal Species
The object of this study was to examine the effects of varying concentrations of 2, 4-D, Dalapon, and Tordon on the growth of several nitrogen-fixing blue-green algal species obtained from soil samples and grown under culture conditions in the laboratory
A miniaturized spectrophotometric in situ pH sensor for seawater
Since the Industrial Revolution, the world\u27s oceans have absorbed increasing amounts of CO2 and the resultant changes to the marine carbonate chemical system have reduced the pH by \u3e 0.1 units (~ 30%) in surface waters. This acidification of the oceans has many far reaching impacts on marine life and there is great need of quality instrumentation to assess and follow the changing carbonate system. This MIS project aims to develop a low cost pH sensor with high precision and accuracy for open sea measurements with special emphasis on reduced size and cost. Design effort is based on the commercially available in situ ocean pH sensor, the SAMI-pH. Emphasis on small size and low cost will allow deployment of the sensors on a much wider variety of platforms than are currently viable thus greatly extending the spatial and temporal resolution of ocean acidification measurements. One such platform is NOAAs Global Drifter Program, a network of non-recovered drifting buoys that has potential for ocean carbon cycle research. A prototype instrument was designed, the inexpensive SAMI-pH or iSAMI-pH. This instrument was entered into the Wendy Schmidt Ocean Health (WSOH) XPRIZE. This was an incentivized global competition to spur innovation in pH sensor technology with both accuracy and affordability prize purses totaling $2 million dollars. The affordability purse consisted of three phases of testing that explored accuracy, precision and stability using a variety of tests that spanned 6 months. It progressed from bench testing in a temperature controlled chamber and a 60 day tank test at the Monterey Bay Aquarium Research Institute (MBARI), to a month long deployment in a specially designed tank at the Seattle Aquarium that used the highly variable waters of Puget Sound. In lab testing, the iSAMI showed ± 0.01 accuracy. In the MBARI test tank, the iSAMI showed precision of ± 0.004 pH units and stability of 0.008 pH units per month with validation uncertainty of ± 0.009 pH units. In the coastal trials, the iSAMI again showed a precision of ± 0.004 pH units and a stability of 0.011 pH units per month with a validation uncertainty of ± 0.012 pH units. Stability or drift was statistically indistinguishable from that of the validation measurements. The iSAMI was in excellent agreement with the commercially available SAMI-pH which won the accuracy prize purse of the WSOH XPRIZE. The iSAMI won the affordability prize purse exceeding the performance metrics by several fold
Analysis of the Detection of Organophosphate Pesticides in Aqueous Solutions Using Hydrogen-Bond Acidic Coating on SH-SAW Devices
The work presented in this paper focuses on the synthesis and characterization of a hybrid organic/inorganic chemically sensitive layer for rapid detection and analysis of OPs in aqueous solutions using SH-SAW devices. Coated SH-SAW devices on 36° YX-LiTaO and 42.75° YX-Quartz (ST-90° X Quartz), are used to determine the optimum operating conditions for achieving rapid sensor responses with high sensitivity. Three analytes (parathion-methyl, parathion, and paraoxon), having similar molecular mass and volume, are used to evaluate the performance of the hybrid organic/inorganic coating in terms of sensor properties of interest including sensitivity, selectivity, reproducibility. It is shown that the coating has a high degree of partial selectivity and sensitivity towards the analytes. With the present non-optimized chemical sensor, a limit of detection of 60 (ppb), 20 (ppb) and 100 (ppb) is estimated for parathion-methyl, parathion, and paraoxon, respectively, when using a 0.5 -thick BPA-HMTS sensing layer. Concentrations as low as 500 (ppb) parathion have been measured. This concentration is significantly much lower than the typical concentrations found on agricultural produce (≥10 ppm)
The state of workplace union reps organisation in Britain today
This article provides a brief evaluation of the state of workplace union reps’ organization in Britain as we approach the second decade of the 2000s. It documents the severe weakening of workplace union organization over the last 25 years, which is reflected in the declining number of reps, reduced bargaining power and the problem of bureaucratization. But it also provides evidence of the continuing resilience, and even combativity in certain areas of employment, of workplace union reps organization, and considers the future potential for a revival of fortunes
Re-Evaluating The Underlying Premises Of Free Market Privatization In Current Dispensation
The contextual framework or policy orthodoxy persuading the implementation of privatization was the prevalent thinking that economic systems functioned best in a “free market”, with little or no government intervention. In the same vein was the belief that a more productive allocation and rationalization of factors of production will dictate a wholesale transfer from public to private sector of the ownership and control of productive assets, their allocation and pricing, including the residual profits flowing from them. The most effective vehicle for such implementation of free market privatization was adjudged to be unfettered deregulation. To the extent that it enabled the untangling of bureaucratic impediments to the inflow and retention of capital to the countries by way of foreign direct investment (FDI) and portfolio investment (PI), including the repatriation of resultant profits, it was a welcome outcome. Unfettered deregulation, as clearly manifested in recent years, particularly in well-known developed economies, appears to have produced an outcome substantially inconsistent with the traditional suppositions, begging the obvious question in the minds of academicians and policymakers alike. Where to, from here? The answer to the apparent conflict and/or contradiction is more urgent in the developing and emerging economies where privatization, and in a broader sense, the ideas and practices based on free market principles and on free market prescriptions have been promoted and sold as sacrosanct, if not necessary for their economic growth and survival. Given the current state of the global financial market which, at best, can be said to be in a state of flux, and the myriads of supposedly economic development initiatives invoking the likes of privatization and deregulation, we are tempted to ask the following questions: Are there any fixes? Could there be better, more accommodating alternative assumption(s), doctrine(s) or paradigm(s)
The influence of plant density on the removal efficiency of volatile organic compounds in indoor air using a biological filter
Self-regulated learning skill as a predictor of mathematics achievement: a focus on ability levels
This paper investigated self-regulated learning skills as a predictor of students’ achievement in mathematics based on ability level. The study is prediction-design research of correlational type. The subjects were 882 SSII students from the secondary schools in Owerri Education Zone of Imo State. The researchers adopted the multi-stage but simple random sampling technique to draw the sample. Two instruments were used to collect data for this study. They are the Self-regulated Learning Questionnaire (SRLQ) and Mathematics Achievement Proforma. The validity of the instruments was ensured through experts’ suggestions and guidance. Single-administration reliability and Cronbach Alpha ensured the reliability of SRLQ (0.89). The data collected were analyzed using regression analysis and coefficient of determination at 0.05 alpha level with the aid of Statistical Package for Social Sciences (SPSS) version 20. The results of the study revealed that self-regulated learning skill predicts 6.0% and 4.3% respectively to the variance observed in high and low achieving students in mathematics. This prediction is significant as attested to by the regression analysis carried out (p < 0.05). Therefore, secondary school students should regulate their learning to increase their mathematics achievement
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