25 research outputs found
Protecting the Privilege of Burning Sugarcane at Harvest
The South African sugar industry burns 90% of the crop at harvest while 10% is harvested green. The trend to burn cane at harvest has increased over the past twenty years, despite growing pressure from the public and environmental legislation. This paper explores the influence that public pressure and legislation are having on the practise of burning and examines the actions that the industry has implemented in order to protect the privilege of burning sugarcane at harvest. A communication model and case studies are used to illustrate the interaction between the sugar industry, government and public role players over cane burning. Communication has proved to be a key management tool that has had to be dynamic and on going in order to engage the various role players effectively. It is presumed that the advantages of burning outweigh those of trashing and it is for the nuisance rather than the health factor that the public want cane burning banned on farms adjacent to residential or tourist areas. The government, however, regards agricultural burning as a contributory factor to high air pollution levels during the winter months and expects these levels to be reduced. Will the public be able to force change to the current practice of burning cane at harvest in the South African sugar industry or will the steps taken by the industry provide adequate protection? Although favourable outcomes have been achieved, cane burning remains under pressure from the public and government.cane burning, communication, environment, legislation, Farm Management,
Mobile telephone-delivered contingency management interventions promoting behaviour change in individuals with substance use disorders: a meta-analysis
BACKGROUND/AIMS:
Contingency management (CM) interventions have gained considerable interest due to their success in the treatment of addiction. However, their implementation can be resource-intensive for clinical staff. Mobile telephone-based systems might offer a low-cost alternative. This approach could facilitate remote monitoring of behaviour and delivery of the reinforcer and minimize issues of staffing and resources. This systematic review and meta-analysis assessed the evidence for the effectiveness of mobile telephone-delivered CM interventions to promote abstinence (from drugs, alcohol and tobacco), medication adherence and treatment engagement among individuals with substance use disorders.
DESIGN:
A systematic search of databases (PsychINFO, CINAHL, MEDLINE PubMed, CENTRAL, Embase) for randomized controlled trials and within-subject design studies (1995-2019). The review was conducted in accordance with the PRISMA statement. The protocol was registered on PROSPERO.
SETTING:
All included studies originated in the United states.
PARTICIPANTS:
Seven studies were found, including 222 participants; two targeted alcohol abstinence among frequent drinkers and four targeted smoking cessation (in homeless veterans and those with post-traumatic stress disorder). One targeted medication adherence.
MEASURES:
The efficacy of CM to increase alcohol and nicotine abstinence was compared with control using several outcomes; percentage of negative samples (PNS), quit rate (QR) and longest duration abstinent (LDA) at the end of the intervention.
FINDINGS:
The random-effects meta-analyses produced pooled effect sizes of; PNS [d = 0.94, 95% confidence interval (CI) = 0.63-1.25], LDA (d = 1.08, 95% CI = 0.69-1.46) and QR (d = 0.46, 95% CI = 0.27-0.66), demonstrating better outcomes across the CM conditions. Most of the studies were rated as of moderate quality. 'Fail-safe N' computations for PNS indicated that 50 studies would be needed to produce a non-significant overall effect size. None could be calculated for QR and LDA due to insufficient number of studies.
CONCLUSION:
Mobile telephone-delivered contingency management performs significantly better than control conditions in reducing tobacco and alcohol use among adults not in treatment for substance use disorders
Mobile telephone-delivered contingency management interventions promoting behaviour change in individuals with substance use disorders: a meta-analysis
BACKGROUND/AIMS:
Contingency management (CM) interventions have gained considerable interest due to their success in the treatment of addiction. However, their implementation can be resource-intensive for clinical staff. Mobile telephone-based systems might offer a low-cost alternative. This approach could facilitate remote monitoring of behaviour and delivery of the reinforcer and minimize issues of staffing and resources. This systematic review and meta-analysis assessed the evidence for the effectiveness of mobile telephone-delivered CM interventions to promote abstinence (from drugs, alcohol and tobacco), medication adherence and treatment engagement among individuals with substance use disorders.
DESIGN:
A systematic search of databases (PsychINFO, CINAHL, MEDLINE PubMed, CENTRAL, Embase) for randomized controlled trials and within-subject design studies (1995-2019). The review was conducted in accordance with the PRISMA statement. The protocol was registered on PROSPERO.
SETTING:
All included studies originated in the United states.
PARTICIPANTS:
Seven studies were found, including 222 participants; two targeted alcohol abstinence among frequent drinkers and four targeted smoking cessation (in homeless veterans and those with post-traumatic stress disorder). One targeted medication adherence.
MEASURES:
The efficacy of CM to increase alcohol and nicotine abstinence was compared with control using several outcomes; percentage of negative samples (PNS), quit rate (QR) and longest duration abstinent (LDA) at the end of the intervention.
FINDINGS:
The random-effects meta-analyses produced pooled effect sizes of; PNS [d = 0.94, 95% confidence interval (CI) = 0.63-1.25], LDA (d = 1.08, 95% CI = 0.69-1.46) and QR (d = 0.46, 95% CI = 0.27-0.66), demonstrating better outcomes across the CM conditions. Most of the studies were rated as of moderate quality. 'Fail-safe N' computations for PNS indicated that 50 studies would be needed to produce a non-significant overall effect size. None could be calculated for QR and LDA due to insufficient number of studies.
CONCLUSION:
Mobile telephone-delivered contingency management performs significantly better than control conditions in reducing tobacco and alcohol use among adults not in treatment for substance use disorders
Reversible self-assembly of superstructured networks
Soft structures in nature, such as protein assemblies, can organize reversibly into functional and often hierarchical architectures through noncovalent interactions. Molecularly encoding this dynamic capability in synthetic materials has remained an elusive goal. We report on hydrogels of peptide-DNA conjugates and peptides that organize into superstructures of intertwined filaments that disassemble upon the addition of molecules or changes in charge density. Experiments and simulations demonstrate that this response requires large-scale spatial redistribution of molecules directed by strong noncovalent interactions among them. Simulations also suggest that the chemically reversible structures can only occur within a limited range of supramolecular cohesive energies. Storage moduli of the hydrogels change reversibly as superstructures form and disappear, as does the phenotype of neural cells in contact with these materials
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Heteroepitaxial Design of Long-Wavelength III-Nitride Light-Emitting Diodes
The group III-nitride material system has emerged as the preferred choice for a wide range of semiconductor optoelectronic applications, ranging from light-emitting diodes (LEDs) for general illumination to red-green-blue micro-LEDs for next generation displays. Properties such as direct bandgaps spanning the visible spectrum, high defect tolerance, and excellent efficiency make InGaN-based LEDs attractive for replacing conventional lighting and display technologies. However, the optical and electrical efficiency decreases significantly when increasing the emission wavelength of nitride LEDs from blue to red, which can be explained in part by materials quality degradation and larger polarization-induced electric fields.
This dissertation focuses on the epitaxial growth and characterization of long-wavelength group III-nitride LEDs emitting in the green to red spectral range. The origin of low electrical efficiency in c-plane green LEDs is first explored using a combined experimental and simulation-based approach. LEDs are grown using metal organic chemical vapor deposition, fabricated into devices, and electrically tested. Three-dimensional LED device simulations based on the Localization Landscape theory of disorder are then conducted to relate nitride materials properties to device performance. These studies demonstrate that polarization barriers at the GaN/InGaN interface and sequential filling of quantum wells (QWs) contribute to the low electrical efficiency in green LEDs.The use of InGaN quantum barriers (QBs) is introduced as an approach to overcome barriers to carrier transport in green LEDs. Structures incorporating InGaN QBs have a reduced polarization discontinuity at the QW/QB interface and contribute an additional source of alloy disorder. Through experiments and three-dimensional simulations, it is shown that InGaN QBs improve electrical efficiency and introduce preferential pathways for vertical transport through regions of high indium content. Next, an approach using engineered V-defects, which have lower total polarization discontinuities for InGaN/GaN interfaces than c-plane, is proposed to mitigate polarization-induced potential barriers in green LEDs. Lastly, efforts to improve green LED performance are extended to red micro-LEDs, where materials degradation and polarization-induced electric fields become more severe. The results presented in this dissertation expand the understanding of long-wavelength LED efficiency and provide a path to realize high-performance green and red LEDs and micro-LEDs through careful heteroepitaxial growth and design
Protecting the Privilege of Burning Sugarcane at Harvest
The South African sugar industry burns 90% of the crop at harvest while 10% is harvested green. The trend to burn cane at harvest has increased over the past twenty years, despite growing pressure from the public and environmental legislation. This paper explores the influence that public pressure and legislation are having on the practise of burning and examines the actions that the industry has implemented in order to protect the privilege of burning sugarcane at harvest. A communication model and case studies are used to illustrate the interaction between the sugar industry, government and public role players over cane burning. Communication has proved to be a key management tool that has had to be dynamic and on going in order to engage the various role players effectively. It is presumed that the advantages of burning outweigh those of trashing and it is for the nuisance rather than the health factor that the public want cane burning banned on farms adjacent to residential or tourist areas. The government, however, regards agricultural burning as a contributory factor to high air pollution levels during the winter months and expects these levels to be reduced. Will the public be able to force change to the current practice of burning cane at harvest in the South African sugar industry or will the steps taken by the industry provide adequate protection? Although favourable outcomes have been achieved, cane burning remains under pressure from the public and government
Agricultural Price-Supporting Measures in Foreign Countries
Report Introduction: Government intervention for the purpose of enabling farmers to obtain higher and more dependable prices for their products has been an outstanding feature of the world agricultural situation in recent years. Historically speaking, such intervention is by no means a recent development; its lineage runs back far into the past. Such familiar devices as tariffs and bounties on agricultural and other products are centuries old. By 1914, moreover, there had been a considerable growth of other and more far-reaching types of activity, both private and governmental, involving systematic and organized efforts to enhance returns from the sale of farm products. Governments had been endeavoring increasingly to influence or control production, trade, and prices; and some progress had been made also in the field of cooperative organization of producers
Sugar economics, statistics, and documents /
Includes map of the American sugar system."Official documents of government agencies of the United States relating to sugar ... June 1930 to March 1938": p. 115-281.Includes bibliographical references and indexes.[v. 2]. Supplement.Mode of access: Internet.v. 1: Burgundy cloth binding; gilt cover title; v. 2: Brown cloth binding; gilt cover title.ACQ: 35669; Janice B. Longone; Gift; 6/21/2001
Impact of doped barriers on the recombination coefficients of <i>c</i>-plane InGaN/GaN single quantum well light-emitting diodes
Differential carrier lifetime measurements were performed on c-plane InGaN/GaN single quantum well (QW) light-emitting diodes (LEDs) of different QW indium compositions as well as with and without doped barriers. Mg-doped p-type and Si-doped n-type barriers close to the QW were used to reduce the net internal electric field in the QW, thereby improving the electronâhole wavefunction overlap on the LEDs. LEDs with doped barriers show short lifetimes and low carrier densities in the active region compared to the reference LEDs. The recombination coefficients in the ABC model were estimated based on the carrier lifetime and quantum efficiency measurements. The improvement in the radiative coefficients in the LEDs with doped barriers coupled with the blueshift of the emission wavelengths indeed indicates an enhancement in wavefunction overlap and a reduction of quantum confined Stark effect as a result of the reduced internal electric field. However, doped barriers also introduce non-radiative recombination centers and thereby increase the ShockleyâReadâHall (SRH) coefficient, although the increment is less for LEDs with high indium composition QWs. As a result, at high indium composition (22%), LEDs with doped barriers outperform the reference LEDs even though the trend is reversed for LEDs with lower indium composition (13.5%). Despite the trade-off of higher SRH coefficients, doped barriers are shown to be effective in reducing the internal electric field and increasing the recombination coefficients.</jats:p
Influence of Superlattice Structure on V-Defect Distribution, External Quantum Efficiency and Electroluminescence for Red InGaN Based ”LEDs on Silicon
Achieving high quantum efficiency in long-wavelength LEDs has posed a significant challenge to the solid-state lighting and display industries. In this article, we use V-defect engineering as a technique to achieve higher efficiencies in red InGaN LEDs on (111) Si through lateral injection. We investigate the effects of superlattice structure on the V-defect distribution, the electroluminescence properties, and the external quantum efficiency. Increasing the relative thickness of In in the InGaN/GaN superlattice and the total superlattice thickness correlate with a reduction of active region defects and increased external quantum efficiencies. The highest measured on-chip EQE was 0.15% and based on Monte-Carlo ray tracing simulations for light extraction we project this would correspond to a flip-chip EQE of ~2.5%