bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Leachate Recirculation On Municipal Solid Waste Landfill Operating Characteristics
Authors: Reinhart Debra R. , Basel Al-Yousfi A.
Published: July 2007

Landfill bioreactor technology offers important advantages in the management and treatment of municipal solid waste, including accelerated waste stabilization rates, enhanced gas production, facilitated leachate management, volume reduction and minimized long-term liability. These advantages have been documented in laboratory-, pilot- and full-scale investigations. Although challenges remain in implementing the technology, bioreactor landfills are designed and operated with increasing frequency. © 1996 ISWA
Using Isotopic and Molecular Data To Model Landfill Gas Processes
Authors: Bogner J.E. , Sweeney R.E. , Coleman D. , Huitric R. , Ririe G.T.
Published: July 2007

Using a large data set, a preliminary investigation has been made to evaluate the usefulness of stable isotope ratios for improving our understanding of methane and carbon dioxide generation in landfills. Included are approximately 130 landfill gas samples from across the U.S.A., and 18 recent samples from: (1) an Argonne Laboratory study area in the Brea-Olinda Landfill, Orange County, California (U.S.A); and (2) several Los Angeles County landfills, California (U.S.A). The following isotope ratios were examined: δ13C for methane, δ13C for carbon dioxide and δD for methane. Using simple ratio plots supplemented by mass-balance calculations, these data show promise for indicating the relative contributions of the four major carbon cycle processes in landfills, namely: (1) direct oxidation of organic material to carbon dioxide; (2) methane generation from fermentation (acetate cleavage); (3) methane generation from carbon dioxide reduction; and (4) methane oxidation to carbon dioxide by methanotrophic bacteria. Both the methane generation and oxidation reactions are central to an explanation of the trends discussed herein. The data also suggest that direct oxidation of organic matter in the refuse may be contributing to the observed isotopic ratios in some cases. The trends observed at the Brea-Olinda site were similar to trends using the large U.S. database, suggesting that isotopic techniques may be useful to better constrain carbon cycle processes common to all landfill settings. © 1996 ISWA
Landfill Fires in Finland
Authors: Ettala Matti , Rahkonen Päivi , Rossi Esko , Mangs Johan , Keski-Rahkonen Olavi
Published: July 2007

On average, there were 633 sanitary landfills in operation in 1990-92 in Finland. Annually, 380 landfill fires occurred, one-quarter of which were deep fires. The total amount of waste burnt in landfill fires was estimated to be 84,000 tonnes year-1. Unsufficient covering and compacting, ash disposal and deliberate fire starting were reported to be the most typical reasons for waste ignition. The most severe deep fires lasted for 2 months. A 10 m high, 35,000 m3 large experimental bank of waste was built, instrumented and set on fire from a 7 m deep well located at the centre of the area. Wood was burnt in this ignition well to produce glowing embers, which were covered with waste and soil layers. No spread of fire was detected after covering the ignition well. However, the fire was not extinguished by covering but remained smouldering throughout the experiment. To extinguish the fire, it was necessary to dig up the smouldering fire and cool it. © 1996 ISWA
Use of Shredded Tires as Lightweight Backfill Material for Retaining Structures
Authors: Cecich Vanessa , Gonzales Linda , Hoisaeter Ase , Williams Joanne , Reddy Krishna
Published: July 2007

Each year in the United States, approximately 242 million automobile, truck and specialty tires are discarded. Almost 78% of these scrap tires wind up in overcrowded landfills, and thousands more are strewn across the country's empty lots, highways and illegal tire dumps. Used tires pose both a serious public health and an environmental threat. Therefore, economically feasible alternatives for scrap tire disposal must be found. Some of the current uses of scrap tires are tire-derived fuel, barrier reefs, and crumb rubber as an asphalt additive. However, all of the recycling, re-use and recovery practices combined only consume about 22% of the discarded tires. Thus, a need still exists for the development of additional uses for scrap tires. This paper addresses one potential use of scrap tires within the civil engineering field. Specifically, the feasibility of using shredded tires as a lightweight backfill material for retaining walls has been investigated.

In this study, laboratory tests were first performed to determine the engineering properties of shredded tires. Based on sieve analyses, the shredded tires used for this study can be classified as uniformly graded material. The unit weight of shredded tires was found to range from 35 to 38 lbs ft-3 (pcf), and the hydraulic conductivity was determined to be 0.03 cm s-1. The values of shear strength parameters, cohesion and angle of internal friction, were determined to be 147 lbs ft-2 (psf) and 27 degrees, respectively. Using these properties, retaining walls of various heights were then designed using shredded tires as the backfill material. Retaining walls were also designed using conventional sand as the backfill material for comparison purposes. When comparing the overall cost for the retaining wall using shredded tires with the retaining wall using sand, a substantial cost saving was realised by the use of shredded tires. An increase in the factor of safety was also a result of using shredded tires instead of sand as backfill. The results of this study indicate that shredded tires have a definite potential to be used as a backfill material for retaining structures.
A Methodology for Quantifying the Volume of Construction Waste
Authors: Yost Peter A. , Halstead John M.
Published: July 2007

Estimates for construction waste generation are often based on per capita multipliers in much the same way as municipal solid waste estimates. This has lead to estimation rates with more than 10-fold variation and little confidence in the resulting estimates. A methodology is offered in this paper that bases construction waste estimates on the financial value of building permits for a variety of types of construction projects. In this way, estimates reflect actual construction activity more closely and are based on a detailed and widely available database from the U.S. Census Bureau. A case study estimating gypsum wallboard waste generation for a region of the United States is described. The case study results were used in the decision-making process by a wallboard manufacturing plant interested in the development of a regional gypsum wallboard recycling programme. © 1996 ISWA
A Study To Define a Standard Health Protection Zone for Sanitary Landfill in Fu Shan City
Authors: Yanfeng Hong  , Shunchang Pan  , Qiang Shoa  , Fan Liu  , Yansheng Duo
Published: July 2007

The concept of a Health Protection Zone for Sanitary Landfill of Urban Refuse has been established in Fu Shan City. It is based on a series of local air quality investigations and measurements. For determining major air pollutants from a sanitary landfill, an area source dispersion model is used to calculate a fugitive emission rate of various air pollutants. According to the Ambient Air Quality Standard of China (GB 3095-82), and by reference to Allowed Concentration in Habitable Areas of America and Japan, a Standard for a Health Protection Zone for Sanitary Landfill of Urban Refuse in Fu Shan has been developed.
The Evaluation of Waste Management Options
Authors: Powell Jane C.
Published: July 2007

Until recently the disposal option for municipal waste was selected purely on the grounds of financial effectiveness, but now with an increased concern for the environment other criteria such as resource use and environmental impact must also be taken into consideration. The incorporation of a range of different criteria into the decision making process is, however, a formidable task. One potential solution is to use multicriteria evaluation which provides for a systematic appraisal of a number of alternative projects on the basis of a series of criteria. In this study the multicriteria evaluation of six waste disposal options (landfill, incineration and refuse-derived fuel (RDF), each with and without recycling) resulted in RDF with recycling coming out as the best option under a variety of weighting scenarios. Only when a high weighting was put on cost criterion did landfill become the better option. © 1996 ISWA
Bio-Aerosol Exposure During Collection of Mixed Domestic Waste—an Intervention Study On Compactor Truck Design
Authors: Breum N.O. , Nielsen B.H. , Møller Nielsen E. , Poulsen O.M.
Published: July 2007

During collection of domestic waste in compactor trucks the waste collectors may be exposed to bio-aerosols. The purpose of this study was to elucidate to what extent an air pollution control system, composed of an air exhaust system mounted behind a plastic lamella curtain covering the scoop of a compactor truck, can reduce the exposure. Personal sampling of airborne contaminants were obtained from two crews collecting mixed domestic waste in containers using either a standard compactor truck or a compactor truck with the air pollution control system.

Exposures were reduced when the waste was collected in the compactor truck with air pollution control as compared with the standard compactor: total dust reduction approximately two-fold (α = 3%); endotoxin reduction approximately two-fold (α = 10%); total microorganisms reduction approximately six-fold (α = 9%); viable bacteria reduction approximately three-fold (α =15%); and viable fungi reduction approximately four-fold (α = 1%). It is concluded that exposure to bio-aerosols during waste collection in compactor trucks can be reduced by mounting an air exhaust equipment behind a plastic lamella curtain covering the scoop of the compactor. © 1996 ISWA
Review of the Use of Swine Manure in Crop Production: Effects On Yield and Composition and On Soil and Water Quality
Authors: Choudhary M. , Bailey L.D. , Grant C.A.
Published: July 2007

The world swine population produces about 1.7 billion tonnes of liquid manure annually. At an application rate of 20 tonnes per hectare, this could fertilize about 85 million hectares of land annually. Storage and disposal of this material presents a challenge to producers because of the potential for environmental pollution. However, because swine manure contains essential plant nutrients, use of swine manure as a soil amendment for crop production is a practical method to solve the disposal problem. The composition and effectiveness of swine manure as a source of plant nutrients depends on several factors including type of ration fed, housing system, method of manure collection, storage and handling. Research has shown that manure application increased soil N, P, K, Ca, Mg and Na. However, heavy or excessive application of manure increased leaching of NO3-N, P and Mg. Swine manure is reported to be effective in increasing the yields of cereals, legumes, oilseeds, vegetables and pastures, and in increasing plant nutrient concentration, especially N, P and K. The efficient use of swine manure can be an agronomically and economically viable management practice for sustainable crop production in temperate regions such as the Canadian prairies where the swine industry is expanding rapidly.
Management Strategies for Oil and Grease Residues
Authors: Stoll Uwe , Gupta Hani
Published: July 2007

The fate of organic oil and fat (i.e. "grease", defined as plant oils/animal fats) from restaurants and other commercial kitchens, is probably one of the most forgotten, yet critical issues in waste management, especially in developing countries. Even in cosmopolitan areas like Bangkok (Thailand), oil and grease are either released into the sewer lines, or are collected manually after separation in grease traps and open dumped with solid waste.

An investigation was made to assess the quantity and characteristics of oil and grease released from commercial kitchens in Bangkok. Based on the results obtained, a holistic management strategy for these residues was developed. The recommendations for oil and grease management were laid down into three options, depending upon the size of the catering establishment, which affects the collection system, and the treatment, re-use and disposal alternatives. The major steps involved in the management scheme are separation and concentration of grease residues in central receiving treatment containers (CRTCs) at a central wastewater treatment plant (CWTP), anaerobic treatment for by-product recovery, and re-use in industrial applications.

For the final disposal of concentrated oil and grease residues and the remaining sludge from anaerobic treatment, priority is given to incineration, together with sewage sludge or solid waste. It is shown that the treatment and disposal of these residues can be integrated into sewage sludge disposal schemes including incineration and anaerobic digestion. Landfill disposal was identified as an intermediate solution, preferably after stabilization. © 1997 ISWA
Serial Batch Tests Performed On Municipal Solid Waste Incineration Bottom Ash and Electric Arc Furnace Slag, in Combination With Computer Modelling
Authors: Baverman Catharina , Sapiej Annika , Moreno Luis , Neretnieks Ivars
Published: July 2007

To predict long-term behaviour of wastes, knowledge is needed about the mechanisms controlling the leaching. The serial batch leaching test, developed in this study, is a version of an ordinary column test that allows sampling at different places in the column. In this study the results from the experiment are compared with computer simulations made with the coupled geochemical and transport program CHEMFRONTS. The experiments showed that some elements, for example potassium, are easily leached, while the leaching of others, for example iron, is slower. The leaching of some elements is solubility controlled whereas others are controlled by dissolution kinetics. The comparison between the experiments and the computer simulations shows good agreement for most elements. A flow through system has been simulated for the steel slag based on the results from the experiments and the computer simulation thereof. The latter simulation gives an idea of the long-term leaching behaviour of the steel slag. The conclusion of the work is that a combination of serial batch leaching test and computer simulation with a geochemical transport program can give good information about the long-term leaching of waste materials. © 1997 ISWA
Numerical Modelling of Generation and Transport of Gas and Heat in Sanitary Landfills Iii. Sensitivity Analysis
Authors: El-Fadel M. , Findikakis A.N. , Leckie J.O.
Published: July 2007

A mathematical model for the generation and transport of gas and heat in a sanitary landfill is developed based on earlier work on the Mountain View Controlled Landfill Project (MVCLP) in California. The present model incorporates biokinetic model equations describing the dynamics of the microbial landfill ecosystem into a multilayer, time-dependent gas and heat transport and generation models. It is based on the fundamental principles governing the physical, chemical, and microbiological processes in a porous media context such as a sanitary landfill. The model includes biochemical and temperature feedback loops to simulate the effects of their corresponding parameters on microbiological processes. The resulting integrated biokinetic, gas, and heat generation and transport model was used to simulate field data from the MVCLP and to assess the sensitivity of model results to biological parameters. The model can be used to predict the rate and total production of methane in a landfill. © 1997 ISWA
Characterization of Urban Wastes According To Fertility and Phytotoxicity Parameters
Authors: Pascual J.A. , Ayuso M. , Garcia C. , Hernández T.
Published: July 2007

Several urban wastes of different nature and level of organic matter stability (municipal solid wastes, sewage sludges and composts) have been characterized analysing fertility and phytotoxicity parameters. Sewage sludges showed the highest N and P values of all the wastes. The total K content of the wastes was low but almost all was available to plants. Mature composts had the lowest organic carbon and humic substances values as a consequence of organic matter mineralization during the composting process. The soluble C at pH 2/precipitated C ratio decreased as the stability of the organic matter increased. In spite of the heterogeneity of the wastes analysed, the organic matter/total organic C ratio was largely constant with a mean value of 2.05. In no case did the heavy metal levels exceed the maximum allowed by the EU disposition for sewage sludges use in agriculture. The highest levels of phytotoxic substances occurred in the fresh wastes. The germination rates and root length were highest with mature composts. Germination index and root length were negatively correlated with water soluble carbon (WSC) and WSC/N ratio. The principal component analysis showed that extractable C, soluble C at pH 2 and water soluble C were the C fractions which most contributed to the total variability. © 1997 ISWA
Melatonin: Role in Development
Authors: Davis Fred C.
Published: July 2007

Melatonin is the mammalian fetus's window to periodicity of the outside world. Through melatonin, the fetus "knows" what time of year it is and, in all likelihood, also knows the time of day. The best known function of melatonin during development is to communicate information about photoperiod and thereby adaptively regulate reproductive development. A second likely function of melatonin during development, which may be related to but more widespread than the first, is to entrain the developing circadian pacemaker. Prenatal maternal entrainment occurs in all of the eutherian mammals in which it has been examined, and in Syrian hamsters exogenous melatonin during development causes entrainment. The broader distribution and greater abundance of melatonin receptors during development, relative to mature animals, suggests that developmental effects of melatonin are greater and more diverse. The human fetal suprachiasmatic nucleus expresses melatonin binding sites and is therefore likely to be affected by both endogenous and exogenous melatonin with consequences for the prenatal and postnatal expression and entrainment of circadian rhythms. Caution is warranted, not only concerning the use of exogenous melatonin during pregnancy and lactation but also concerning behavior that might disrupt the mother's endogenous melatonin rhythm.
Homeostatic versus Circadian Effects of Melatonin on Core Body Temperature in Humans
Authors: Cagnacci Angelo , Kräuchi Kurt , Wirz-Justice Anna , Volpe Annibale
Published: July 2007

Evidence obtained in animals has suggested a link of the pineal gland and its hormone melatonin with the regulation of core body temperature (CBT). Depending on the species considered, melatonin intervenes in generating seasonal rhythms of daily torpor and hibernation, in heat stress tolerance, and in setting the CBT set point. In humans, the circadian rhythm of melatonin is strictly associated with that of CBT, the nocturnal decline of CBT being inversely related to the rise of melatonin. Whereas there is inconsistent evidence for the suggestion that the decline of CBT may prompt the release of melatonin, conversely, stringent data indicate that melatonin decreases CBT. Administration of melatonin during the day, when it is not normally secreted, decreases CBT by about 0.3 to 0.4°C, and suppression of melatonin at night enhances CBT by about the same magnitude. Accordingly, the nocturnal rise of melatonin contributes to the circadian amplitude of CBT. The mechanisms through which melatonin decreases CBT are unclear. It is known that melatonin enhances heat loss, but a reduction of heat production cannot be excluded. Besides actions on peripheral vessels aimed to favor heat loss, it is likely that the effect of melatonin to reduce CBT is exerted mainly in the hypothalamus, where thermoregulatory centers are located.Recentobservationshaveshownthattheacutethermoregulatoryeffects induced by melatonin and bright light are independent of their circadian phase-shifting effects. The effect of melatonin ultimately brings a saving of energy and is reduced in at least two physiological situations: aging and the luteal menstrual phase. In both conditions, melatonin does not exert its CBT-lowering effects. Whereas in older women this effect may represent an age-related alteration, in the luteal phase this modification may represent a mechanism of keeping CBT higher at night to promote a better embryo implantation and survival.
Photic Entrainment of the Mammalian Rhythm in Melatonin Production
Authors: Illnerová Helena , Sumová Alena
Published: July 2007

This review summarizes studies on the photic entrainment of the circadian rhythm in the rat pineal melatonin production, namely of the rhythm in N-acetyltransferase (NAT) activity, and compares the NAT rhythm resetting with preliminary results on the resetting of an intrinsic rhythmicity in the suprachiasmatic nucleus (SCN) of the hypothalamus, namely with the entrainment of the rhythm in the light-induced c- fos gene expression. Phase delaying of the NAT rhythm after various light stimuli proceeds within 1 day with almost no transients, whereas during phase advancing of the rhythm only the morning NAT decline is phase advanced within 1 day and the evening rise phase shifts through transients. A light stimulus encompassing the middle of the night may phase delay the evening NAT rise, phase advance the morning decline, compress the rhythm waveform, and eventually lower its amplitude. Similarly, a long photoperiod compresses the NAT rhythm waveform. The magnitude of phase shifts of the NAT rhythm, as well as their direction, depends on a previous photoperiod. Phase shifts of the evening rise in c- fos gene photoinduction in the SCN and of the morning decline are similar to those of the pineal NAT rhythm after all light stimuli studied so far. The data indicate that the resetting of the rhythm in melatonin production in the rat pineal gland reflects changes in the SCN functional state and suggest that the underlying SCN pacemaking system is complex.
Resetting the Melatonin Rhythm with Light in Humans
Authors: Shanahan Theresa L. , Zeitzer Jamie M. , Czeisler Charles A.
Published: July 2007

The endogenous circadian rhythm of melatonin in humans provides information regarding the resetting response of the human circadian timing system to changes in the light-dark (LD) cycle. Alterations in the LD cycle have both acute and chronic effects on the observed melatonin rhythm. Investigations to date have firmly established that the melatonin rhythm can be reentrained following an inversion of the LD cycle. Exposure to bright light and darkness given over a series of days can rapidly induce large-magnitude phase shifts of the melatonin rhythm. Even single pulses of bright light can shift the timing of the melatonin rhythm. Recent data have demonstrated that lower light intensities than originally believed are capable of resetting the melatonin rhythm and that stimulation of photopically sensitive photoreceptors (i.e., cones) is sufficient to reset the endogenous circadian melatonin rhythm. In addition to phase resetting, exposure to light of critical timing, strength, and duration can attenuate the amplitude of the endogenous circadian rhythm of melatonin. Measurement of melatonin throughout resetting trials provides a dynamic view of the resetting response of the human circadian pacemaker to light. Future studies of the melatonin rhythm in humans may further characterize the resetting response of the human circadian timing system to light.
Circadian Entrainment and Phase Shifting in Mammals with Melatonin
Authors: Redman Jennifer R.
Published: July 2007

Circadian effects of exogenous melatonin, whereby daily administration induces entrainment or phase shifts, have been demonstrated in both nocturnal and diurnal mammals. In Long-Evans rats, as used in early studies, effects occur reliably when melatonin is administered late in the subjective day. A second period of sensitivity to melatonin, late in the subjective night, is evident in certain strains of mice and the diurnal Funambulus pennanti. This late night to early morning sensitive phase previously had been identified in human subjects. Different circadian responses to melatonin also may occur between rat strains. Circadian effects of melatonin in hamsters are diverse and vary with strain, developmental age, and method of administration. Characteristics of melatonin binding sites within the suprachiasmatic nuclei vary both between and within species, as do profiles of endogenous melatonin rhythms. These differences may explain the variations in circadian responses to melatonin.
Exogenous Melatonin's Phase-Shifting Effects on the Endogenous Melatonin Profile in Sighted Humans: A Brief Review and Critique of the Literature
Authors: Lewy Alfred J. , Sack Robert L.
Published: July 2007

Melatonin's phase-shifting effects in humans are thought by some investigators to be subtle, particularly in comparison to those achieved with appropriately timed bright light exposure. The initial study in sighted people was only intermittently successful in phase advancing the endogenous melatonin profile. The study of free-running blind people showed statistically significant phase advances the day after melatonin administration. When holding the light-dark cycle constant, consistent phase advances the day after melatonin administration in sighted people were first shown in the course of describing the melatonin phase response curve (PRC), which also provided the first evidence that melatonin could cause phase delays. More recent studies have replicated the PRC and shown that phase shifts can occur in response to physiological doses within 1 day. This article reviews this literature and attempts to reconcile some of the results from differing studies. If the timing of melatonin administration is optimized according to the melatonin PRC, then consistent phase advances and delays can be achieved. If a reliable and sensitive circadian phase marker (e.g., the highly resolved dim light melatonin onset) is used, then phase shifts can be demonstrated consistently—even a small shift the day after a single physiological dose. The present authors predict that in the near future, melatonin administration will become as useful as bright light exposure in the treatment of circadian phase disorders.
Efficacy of Melatonin Treatment in Jet Lag, Shift Work, and Blindness
Authors: Arendt Josephine , Skene Debra J. , Middleton Benita , Lockley Steven W. , Deacon Stephen
Published: July 2007

Melatonin has chronobiotic properties in humans. It is able to phase shift strongly endogenous rhythms, such as core temperature and its own endogenous rhythm, together with the sleep-wake cycle. Its ability to synchronize free-running rhythms has not been fully investigated in humans. There is evidence for synchronization of the sleep-wake cycle, but the available data suggest that it is less effective with regard to endogenous melatonin and core temperature rhythms. When suitably timed, most studies indicate that fast release preparations are able to hasten adaptation to phase shift in both field and simulation studies of jet lag and shift work. Both subjective and objective measures support this statement. However, not all studies have been successful. Careful evaluation of the effects on work-related performance is required. When used to alleviate the non-24-h sleep-wake disorder in blind subjects, again most studies report a successful outcome using behavioral measures, albeit in a small number of individuals. The pres suggest, however, that although leep-wake can be stabilized to 24 h, entrainment of other rhythms is exceptionally rare.
Melatonin and the Circadian Regulation of Sleep Initiation, Consolidation, Structure, and the Sleep EEG
Authors: Dijk Derk-Jan , Cajochen Christian
Published: July 2007

The endogenous circadian rhythm of melatonin, driven by the suprachiasmatic nucleus, exhibits a close association with the endogenous circadian component of the sleep propensity rhythm and the endogenous circadian component of the variation in electroencephalogram (EEG) oscillations such as sleep spindles and slow waves. This association is maintained even when the sleep-wake cycle is desynchronized from the endogenous circadian rhythm of melatonin. Administration of melatonin during the day increases daytime sleep propensity as indexed by both the latency to sleep onset and sleep consolidation. The EEG during daytime sleep after melatonin administration exhibits characteristics reminiscent of the nocturnal sleep EEG, that is, increased sleep spindle activity and reduced slow-wave sleep and slow-wave activity as detected by quantitative EEG analysis. Administration of higher doses of melatonin (5 mg or more) prior to nocturnal sleep results in an increase in rapid eye movement (REM) sleep. These data demonstrate that melatonin exerts effects on the main characteristics of human sleep, that is, latency to sleep onset, sleep consolidation, slow waves, sleep spindles, an M sleep. There is a need for further studies using physioloRical doses and delivery systems that generate physiological plasma melatonin profiles to firmly establish the role of the endogenous circadian rhythm of melatonin in the circadian regulation of sleep.
Melatonin: Role in Gating Nocturnal Rise in Sleep Propensity
Authors: Lavie Peretz
Published: July 2007

The present article reviews the evidence that melatonin possesses sleep-inducing effects and that it gates the increase in nocturnal sleepiness. It is shown that, without exception, all the studies that have investigated daytime administrations of melatonin reported increased sleepiness, even at doses that do not increase plasma levels of melatonin beyond its physiological levels. By contrast, nighttime increase in sleepiness was achieved only after administration of high doses. Based on these findings and on the precise coupling between the endogenous nocturnal increase in melatonin secretion and the opening of the sleep gate, it is suggested that melatonin participates in the regulation of the sleep-wake cycle by inhibiting the central nervous system wakefulness generating system. This inhibition allows a smooth transition from wakefulness to sleep. Clinical findings on decreased levels of nocturnal melatonin in chronic insomniacs, and on the efficacy of exogenous melatonin in improving sleep in melatonin-deficient insomniacs, are congruent with this hypothesis.
Reproductive Safety of Melatonin: A "Wonder Drug" to Wonder About
Authors: Weaver David R.
Published: July 2007

By some accounts, melatonin is the wonder drug of the 1990s. This previously obscure hormone came to the public's full attention as the result of a series of popular books claiming therapeutic benefits of melatonin ingestion. Some of these claims deserve serious consideration and investigation, whereas others appear unfounded. Without waiting for the outcome of the ongoing scientific debate, however, melatonin set astounding sales records. The hormone is now ingested on a daily basis by many thousands of people. There is little information on the potential adverse effects of melatonin ingestion in humans. Melatonin, its analogs, and its metabolites are not mutagenic, and melatonin possesses remarkably low acute toxicity in animals and humans. It is more difficult to exclude toxic effects of long-term melatonin treatment. The fact that melatonin is normally secreted each night does not ensure that exogenous melatonin, taken at other times and/or in supraphysiological doses, will not have adverse effects. Despite the well-recognized role of melatonin in the regulation of reproduction in photoperiodic species, it seems unlikely that chronic ingestion of moderate melatonin doses will have a profound impact on reproductive function in humans. Evidence that melatonin modulates steroid hormone action in some steroid-responsive tissues suggests that these tissues should be carefully examined when attempting to assess whether melatonin has chronic toxicity in humans. In the absence of sufficient information regarding the long-term safety of exogenous melatonin, the conservative course of action is to restrict melatonin use to those therapeutic applications in which a significant benefit is expected. The decision to ingest melatonin should be preceded by careful consideration of the expected benefits as well as the potential costs of treatment, with recognition of the fact that there has been exaggeration of the benefits and little attention paid to the potential costs in most discussions of this issue to date.
Melatonin Modulates Vascular Smooth Muscle Tone
Authors: Mahle Cathy D. , Goggins Gregory D. , Agarwal Puja , Ryan Elaine , Watson A. John
Published: July 2007

The molecular cloning of a family of melatonin receptors has created a renewed interest in the diverse actions of the hormone melatonin. The redioligand 2-[125I]iodomelatonin has identified potential sites of action for melatonin throughout the central nervous system and periphery of numerous species. Interestingly, in addition to the suprachiasmatic nucleus (the "biological clock"), 2-[125I]iodomelatonin binding sites have been localized to the rat caudal and cerebral arteries. Furthermore, in vitro, melatonin has been shown to induce a concentration-dependent vasoconstriction of rat caudal and cerebral arteries, and pig and human coronary arteries. The lack of melatonin receptor subtypeselective agonists and antagonists prevents the full pharmacological characterization of these responses. The physiological significance of the in vitro vasoconstrictive properties is far from clear, however; in rats, melatonin has been shown to reduce cerebral blood flow. The widespread use of melatonin warrants appropriately designed studies to probe the role of melatonin and its receptors in the modulation of in vitro vascular tone.
Men in Families
Authors: Sinacore Ada L. , Özge Akçali F.
Published: July 2007

This study assesses the effects of the family environment on men's job satisfaction and self-esteem. The results indicate that men's family environment as measured by the Family Environment Scale (Moos & Moos, 1974) predicts only three aspects of job satisfaction as measured by the Job Descriptive Index (Smith, Kendal, & Hulin, 1975). In addition, results indicate that the family environment has a limited effect on men's self-esteem as measured, by the Four Component Self-Esteem Scale (Hampilos, 1988). The authors conclude that the limited relationship between these measures may be due to men's lack of involvement in their family and that men continue to have a traditional view of their role in the family as that of provider and disciplinarian. Implications for counseling are discussed.
Women Face Unemployment: A Comparative Analysis of Age Groups
Authors: Kulik Liat
Published: July 2007

The study examined differences in job search intensity, attitudes toward unemployment, and related responses among four age groups of jobless women in Israel, all of whom were married: Post-adolescence (up to age 21); young adulthood (age 22-35), mid-life (age 36-49); and late adulthood (50-62). The findings revealed differences in job search intensity for the four age groups. The youngest group spent more time seeking employment per week than did the other groups. At the same time, women in the late adulthood group were least likely to reject job offers owing to financial considerations, whereas those in the young adult and mid-life groups tended to reject job offers either due to conflict with family obligations or to work conditions. Moreover, the older respondents reported a sharper decline in health following unemployment than did their younger counterparts. In the same vein, members of the late adulthood group reported less financial strain as a result of unemployment than did the rest of the groups.
Choice of Holland's Social Type College Majors for U.S. Racial/Ethnic Groups
Authors: Trusty Jerry , Ng Kok-Mun , Ray Dee
Published: July 2007

We used national data to study the longitudinal effects of several variables on choice of Holland (1997) social type college majors versus other majors. We examined these effects for four of the five major U.S. racial/ethnic groups, Asian/Pacific Islanders, Hispanics, Blacks, and Whites. Effects of mathematics scores and gender on choice of social majors were fairly consistent across racial/ethnic groups, whereas effects of reading scores and SES differed across racial/ethnic groups. Results for Whites were most consistent with Holland's theoretical formulations regarding the effects of variables on choice of social-type educational/occupational environments.
Elementary School Career Awareness: A Visit to a Hospital
Authors: Beale Andrew V.
Published: July 2007

A well-conceived field trip to a hospital serves several important purposes for elementary school students: (1) it acquaints students with local places of employment while demonstrating the essentiality of work and the need for employees to work together to provide valuable community services, and (2) it helps to reduce the level of anxiety children generally associate with their own hospitalization. In order for a field trip to be something more than a relatively meaningless out-of-school frill, it needs to be carefully planned and carried out. This article offers numerous practical suggestions for getting ready for the hospital visit, the tour itself, and ways to follow-up on the visit, thereby maximizing the educational value of the field trip for elementary age students.
Innovations in Career Counseling
Authors: Lee Felissa K. , Johnston Joseph A.
Published: July 2007

The work world is now full of uncertainty and change as a result of forces such as globalization, downsizing, advancing technology, and increased diversity in the work force. Further, people cannot count on maintaining a job with one company, or even one career, throughout their work lives. In order to meet clients' needs, career counselors must utilize approaches that are compatible with these realities. We review a set of approaches for career counseling that should be effective for clients now and into the future. Specifically, we argue for a holistic approach to career counseling, use of the Personal Career Theory as a client-centered approach to counseling sessions, incorporating creative interventions that draw upon chance events and flexible decision-making, and an emphasis on building interpersonal skills and relationships. We conclude with a summary of recommendations for career counseling practice.
Cyberspace, the New Frontier
Authors: Miller Kristina L. , McDaniels Robert M.
Published: July 2007

The article examines the impact of technology on career services practitioners and administrators, our customers, the educational system, and the society in general. It attempts to identify some of the different paths along which technology is moving, and how these different paths will impact our profession, delivery systems, and the need for training on one hand, and on the other, how we communicate, live, and survive in our ever changing society. Technological advances may not follow what we think should happen, nor can we undo what has already happened, so our focus will be on the future, or what could happen. The authors present a description of some of the uses of technology in career services, like virtual fairs, job posting programs, chat rooms, resume programs, work study employment, and basic career service web sites. They also address concerns regarding who is attempting to provide services to our students, what credentials and/or training those individuals possess, and the purpose of their efforts.
Genetically Determined Polymorphisms in Drug Metabolism
Authors: Lam Y.W. Francis , Marshall Milton V.
Published: July 2007

Many factors can influence the metabolism and disposition of drugs. Genetically determined differences in an individual's capacity to metabolize drugs are known causes of interindividual and interethnic variabilities in drug disposition and response. In general, a poor metabolizer for a specific metabolic pathway would likely develop adverse effects, and an extensive metabolizer for the same metabolic pathway might have less than optimal response. Although there are different types of polymorphism in drug metabolism, polymorphisms in debrisoquine-type oxidation, S-mephenytoin oxidation, and N-acetylation have been the most extensively studied. This article will present the basic concepts of pharmacogenetics, review the major types of metabolic polymorphisms, outline ways to determine phenotyping and genotyping differences in metabolizing enzyme activities, and discuss how these differences relate to drug metabolism, response, and toxicity. When evaluating drug response and adverse reactions in individual patients, an awareness of genetic differences in metabolic capacities would help contribute to optimization in drug therapy.
The Clinical Significance of the Pharmacogenetics of Cardiovascular Medications
Authors: Straka Robert J. , Marshall Peter S.
Published: July 2007

Inter-individual variability in the response to numerous drugs can be traced to a number of sources. One source of variability in drug response is the variability associated with the metabolic capacity of an individual. The component of metabolic capacity that will be the focus of this article is that determined by heredity. Pharmacogenetics is frequently referred to as the study of the effects of heredity on the disposition and response to medications. This article will review the pharmacokinetic and pharmacodynamic significance of pharmacogenetics as it pertains to a select number of cardiovascular agents. The enzyme systems responsible for drug metabolism discussed in this article will be limited to the P-450IID6 and N-acetylation pathways. Given the extensive use of cardiovascular agents in clinical practice that are affected by this genetic polymorphism, it is important for the practicing pharmacist to be aware of this phenomenon and its implications. Hopefully, the knowledge gained from this article will help practicing pharmacists to appreciate the clinical significance of polymorphic drug metabolism and provide a basis for the application of this knowledge to a variety of practice settings.
Devolution and the New Context for Public Policy-making: Lessons from the EU Structural Funds in Wales
Authors: McAllister Laura
Published: July 2007

This article explores the new interface between the National Assembly for Wales and the civil service in Wales through a consideration of the dynamics of the planning process for Wales' first European Objective One Structural Fund programme. The advent of devolution has instigated significant changes in the focus, operation and management of the civil service in Wales which, nevertheless, remains part of the unified British service. The most important development sees civil servants more closely involved in the machinery of government through a directly elected National Assembly. This article examines some of the tensions faced by civil servants in developing a distinctive Welsh dimension to policy-making and in adjusting to a more accountable and transparent policy environment. It assesses the extent to which administrative and political dynamics have been harnessed in an efficient and effective manner to facilitate the planning and delivery of the Objective One programme. Through this analysis, lessons may be drawn for public policy practitioners elsewhere as to the changed context for operationalising major policies within the fluid context of UK-wide devolution. Finally, some issues are identified that may infuture intensify calls for a separate or differently run Welsh civil service.
Changes to the North East Regional - Local Dynamic: New Forms of Governance from Traditional Public Sector Structures?
Authors: Cockerill Tony , Liddle Joyce , Southern Alan
Published: July 2007

Recent moves towards devolution and decentralisation in the UK have produced a mixture of outcomes. The independence achieved in Wales and Scotland combines two very different approaches while the regional issue in Northern Ireland is a central component of the peace process. In the English regions the workings of the Regional Development Agencies (RDAs) now receive less attention although they are regarded as having a substantive role in supporting the social and economic wellbeing of the regions. Even at this macro-level there appear to be problems of fit' between good regional intentions enshrined in Regional Economic Strategies (RES) and more local implementation.

By looking at the North East case, the authors argue that changes to the regional - local dynamic are necessary to the restructuring of the social and economic landscape of the region. This means that new competencies are needed to support the forms of regional governance that are taking shape; a process that is far from finally determined. The authors show that there is still much to be done in terms of setting up new sub-regional partnerships which will carry great responsibility for ensuring that the objectives of the RES are met. The authors point out that these competencies are based on existing and emergent social relations that are in part grounded in traditional public sector structures. As this regional-local dynamic unfolds the authors claim that here is a story at its beginning rather than near its finale.
Customer Service and the Dilemma of Product Warranty
Authors: Kumar Sushil , Singh Shailendra
Published: July 2007

Responding to economic liberalization and realizing the great market potential, a number of multinational enterprises (MNEs) based in developed countries are expanding their operations to the developing world, either through foreign direct investment or through joint ventures. These MNEs are trying to translocate product quality standards as well as customer service standards from their home countries to host countries. In the process, customer expectations from these MNEs in the developing countries have risen very high, but the MNEs are struggling to meet them, especially with respect to the customer service aspect. They are facing many constraints; the major ones have to do with the archaic outlook and traditional mode of doing business by their dealerships. This case summarizes some such problems being faced by one multi-national automobile giant in India—FastTrack Motors India Limited. The case has a strong essence of customer satisfaction and deals with different stages of customer reaction.
Pronto Promotionals
Authors: Asad Usman , Rana Arif
Published: July 2007

This case is about a promotional products company, Pronto Promotionals, established in 1994 by the two siblings Saulat Salahuddin and Najaf Yawar. Pronto from day one followed a leveraged growth strategy, relying heavily on sub-contracting and developing partnerships with specialized small and medium-sized vendors while retaining certain key activities in-house. Although the cost of different products offered by Pronto had decreased considerabily over the years, Pronto was still not very profitable. Najaf had just left the business and Saulat was reflecting on how to turn the company around.
Lahore Woven Garments Consortium (LGC)
Authors: Ghani Javed , Fayyaz Anjum
Published: July 2007

In October 2005 Jawwad Chaudhry, Director Musterhaft and Chairman LGC, was reflecting upon the performance benefits and sustainability of the Lahore Garments Consortium (LGC) Guarantee Limited. LGC consisted on eight woven garment manufactures and exporters. The CEOs of Musterhaft and Cotton Web were two particularly active members of LGC. Members of the consortium benefitted from joint purchases, joint skill development and joint marketing. Variations in the size of the firms in terms of number of machines, employees, product quality and target markets were some of the factors influencing the ability to develop consensus and a shared vision among consortium members.