Effect of corn tillage system on physical properties of the soil and on bio-factors of plants

Corn (Zea mays L.) is the most valuable crop in the United States and is grown on more acres than any other harvested crop. Crop production in the United States centers in the north central states and has more than doubled in the last 30 years, rising from 2.1 to 5.5 billion bushels. In 1970, United States corn production accounted for 48% of the total world output (74). Tillage is one of the oldest practices in the production of crops; it has been used by man since ancient times, Although rapid advances have been made during the last century, it is still far from an exact science, Farmers must still guess at the amount of tillage to employ for seedbed preparation and cultivation. The use of tillage tools has been and is still being governed largely by estimation based on past experiences (50). Many of the principles of good tillage practice have been handed down from generation to generation and only over the past three decades have various sciences been applied to the practice of tillage. Thus, agronomists and agricultural engineers with the farmers have become more concerned about the complexity of the tillage process and knowledge of soil. They are seeking the needed physical manipulation of soil to increase production and decrease erosion

The Results of Some Tests of Mechanism Designs for the Allocation and Pricing of Collections of Heterogeneous Items

During the discussion and evaluation of proposals for the design of the Federal Communications Commission (FCC) mechanism to sell the spectrum, over 130 auctions were run under controlled conditions at Caltech for the National Telecommunications and Information Administration (NTIA), the FCC and others. In this paper we look at these data and try to extract some useful findings for those who may be involved in creating future designs of similar auctions. For those whose experience with experimental economics methodology is limited, we begin with a section on the general framework within which experimental work underlying applied mechanism design is conducted. Next we cover, in section 2, the various technical pieces needed to understand the data: performance measures, economic environments, mechanisms tested, and the major issues considered. The experimental data are presented and our observations are summarized in section 3. We end, in section 4, with some thoughts for future work and with the observation that there is a huge gap between, theory, scientific evidence, and practice in the design of complex auctions. Much needed research remains to be done

Use of a rhodamine-based chelator in a microfluidic paper-based analytical device for the in-situ copper quantification in natural waters

This work describes the development of a microfluidic paper-based analytical device (μPAD) for the determination of copper in fresh and marine waters. A functionalized rhodamine-based chelator was synthesized and used as a chromogenic reagent, forming a highly intense pink complex with the analyte. The aim was to create a paper device that offers optimal performance and provides in-situ, rapid and cost-effective analysis in line with World Health Organization guidelines. The influence on the determination of several physical and chemical parameters was evaluated aiming to achieve the best performance. Under optimised conditions, a linear correlation was established in the range of 0.05–0.50 mg L−1 of copper, with a limit of detection of 10 μg L−1. The accuracy of the proposed method was assessed by comparing the results obtained with the developed μPAD and the results obtained with Inductively Coupled Plasma measurements (RE < 10 %). Recovery studies were also performed using different types of water samples with no need for any prior sample pre-treatment: tap, well, river and seawater. The average recovery percentage of 101 % (RSD = 4.3 %) was obtained, a clear indication of no multiplicative matrix interferences.info:eu-repo/semantics/publishedVersio

A gas diffusion sequential injection system for the determination of sulphur dioxide in wines

In the present work, a sequential injection system with spectrophotometric detection was developed for the determination of free and total sulphur dioxide in wines. It was based on the formation of a coloured product from the reaction among SO2, formaldehyde and pararosaniline. A gas diffusion unit (GDU) was incorporated into the manifold to prevent the wine matrix interference in the spectrophotometric measurement. An acid solution was added to the sample prior to its passage through the donor channel of the GDU to promote gaseous SO2 formation. For the free SO2 determination, the sample was directly aspirated into the holding coil; for the total SO2 determination, the sample was processed after previous in-line hydrolysis of bound SO2 with an alkali solution. Two second-order calibration curves were established, defining two concentration ranges: 2–40 mg l−1 for the free SO2 determination and 25–250 mg l−1 for the total SO2 determination. Relative standard deviations (n=10) were lower than 1.2% for the determination of free SO2 and lower than 2.3% for the determination of total SO2. The sample frequency was about 16 h−1. This methodology was applied to the determination of free and total sulphur dioxide in 10 table wines and the results were statistically comparable with those furnished by the recommended procedure

Analysis of human activities and identification of uncertain situations in context-aware systems

One of the main obstacles faced by context-aware systems developed for human activities recognition is related to dealing with incomplete data for decision making. Problems from several sources contribute to this phenomenon. Imprecise acquisition of data from sensors and the system’s design issues are among them. This paper presents an approach to tackle this trouble by dividing it into three parts. The first one refers to the validation of context data through an Attribute Grammar. The formalism and expressiveness provided a grammar, enriched with attribute evaluation rules and contextual constraints, ensures that the system will use only valid data for reasoning. Anomalous data will be detected, and the situation will be signalized. Also, the analysis of Quality of Context is provided, considering a set of characteristics, vouching that only useful information will be considered. At last, the identification of the sources of uncertain situations followed by a sequence of actions aiming to minimize the negative impacts of it helps the system to work with more complete sets of data. The formalization of the approach is provided together with an algorithm to validate it.FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/202

Enzymatic determination of ethanol and glycerol by flow injection parallel multi-site detection

A flow injection method was developed for the sequential enzymatic determination of ethanol and glycerol in wines, using immobilised ethanol dehydrogenase and glycerol dehydrogenase, respectively. The enzymes were immobilised separately on alkylaminated controlled pore glass. A multi-site spectrophotometric detection system was used in parallel configuration to monitor the absorbance change in the two independent analytical channels. A 50-fold dilution of the samples was necessary before injection. The working range was between 0.05 and 0.5% (v/v) for the ethanol and between 0.03 and 0.3 g l−1 for the glycerol determination, with corresponding detection limits of 2 10−3%(v/v) and 2 10−3 g l−1. Relative standard deviations (R.S.D.) (nD9) lower than 2.3% for the ethanol and 2.1% for the glycerol determination were found. For 13 samples of different types of table and Port wines, the results showed good agreement with the corresponding reference procedures; a two level recovery study also showed good accuracy for the developed methods. The sampling rate was 10 h−1, corresponding to 20 determinations per hou