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Heavy deposits of charcoal and associated Zea pollen recovered from the Aguada Petapilla in the Copan Valley of western Honduras strongly support Hugh Iltis's hypothesis concerning the early domestication and use of maize. Evidence of burning and cultivation appear at approximately 2600–2700 b.c., predating the earliest direct archaeological evidence for human occupation of the region by more than 1,000 years. These Copan data are in close agreement with two other sediment cores from Honduras, and also with maize macrofossils recently recovered from dry deposits in El Gigante Cave.

Pollen and charcoal analysis of a 5.3-m sediment core from Aguada Petapilla, a peat bog, provides evidence of late Holocene vegetation and fire history in the Copan Valley, Honduras. Low concentration and preservation problems characterized the pollen flora, but there are taxa present indicative of major agricultural trends, including Zea mays. Microscopic charcoal fragments are well represented and record continued burning in the region since the lowest level of the core (5700 B.P. [3750 B.C.]). Presence of Zea indicates that maize farming was initiated by as early as 2300 B.C. Three peaks in charcoal-fragment frequencies occur in periods centered approximately at 900 B.C., 400 B.C., and A.D. 600. Fires in this relatively dry region of the southern Maya Lowlands (whose mean annual rainfall is about 1,400 mm) could have resulted from natural forest fires or human agricultural clearing at any time in the Holocene. This contrasts with wetter areas of tropical Central and South America (mean annual rainfall of about 2,500–4,000 mm) where significant climatic drying is required to ignite primary tropical forest.

This practice parameter describes treatment with stimulant medication. It uses an evidence-based medicine approach derived from a detailed literature review and expert consultation. Stimulant medications in clinical use include methylphenidate, dextroamphetamine, mixed-salts amphetamine, and pemoline. It carries FDA indications for treatment of attention-deficit/hyperactivity disorder and narcolepsy.

This parameter reviews the current state of the prevention and management of child and adolescent aggressive behavior in psychiatric institutions, with particular reference to the indications and use of seclusion and restraint. It also presents guidelines that have been developed in response to professional, regulatory, and public concern about the use of restrictive interventions with aggressive patients with regard to personal safety and patient rights. The literature on the use of seclusion, physical restraint, mechanical restraint, and chemical restraint is reviewed, and procedures for carrying out each of these interventions are described. Clinical and regulatory agency perspectives on these interventions are presented. Effectiveness, indications, contraindications, complications, and adverse effects of seclusion and restraint procedures are addressed. Interventions are presented to provide more opportunities to promote patient independence and satisfaction with treatment while diminishing the necessity of using restrictive procedures.

Questions of past human-environment interactions are best addressed by a research agenda that recovers complementary archaeological and paleoenvironmental data. We have used such an approach in our investigations at Laguna Tamarindito, a small lake located in the SW part of the Peten rainforest of Guatemala. In 1991, a sediment core was taken from the lake as part of a larger program of research examining the history of human-environment interactions in the Petexbatun region. We employ a conjunctive analytic approach to interpret the core, including archaeological survey of the lake's watershed, physical and chemical analysis of sediments, palynology, and molluscan ecology. Our analysis of this core reveals substantial paleoecological information about the past 10,000 years in this region. Study of the lake sediments, pollen, and gastropod populations indicates variation in regional climate, including two periods of significant drying. Changes in the rate of sediment at ion in the lake can be rela...

The Petexbatun region has a series of upland ridges surrounded by lowland wetlands. In Preclassic times, ancient Maya peoples began colonizing the region along waterways. Although few in number, they cleared large areas of upland tropical forest for agriculture and induced significant soil erosion. Population contracted in the region during the Early Classic, and mature tropical forest growth returned. During the Late Classic, population expanded rapidly across the region, forest clearance resumed, and desirable, intensively cultivated, upland areas were divided by an elaborate wall system. Upland agriculture during the Late Classic included the use of several types of terracing that significantly checked soil erosion during this period. Considerable variation may have existed between the urban agriculture practiced in the region's three major centers—Dos Pilas, Tamarindito, and Aguateca.

The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculatedmore » to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis found a number of modifications and adjustments that could provide higher efficiency and better use of available work. Conclusions from this analysis will help guide the analyses and CFD modeling in future process development. The MBB technology has the potential to be a disruptive technology that will enable coal combustion power plants to be built and operated in a cost effective way, cleanly with no carbon dioxide emissions. A large amount of work is needed to quantify and confirm the great promise of the MBB technology. A Phase 2 proposal was submitted to DOE and other sponsors to address the most critical MBB process technical gaps. The Phase 2 proposal was not accepted for current DOE support.« less

Settlement research at Copán, Honduras, since 1984 has produced the largest set of obsidian-hydration dates from excavated contexts available for Mesoamerica (Webster and Freter 1990). Geoffrey Braswell (1992) has criticized the methodology underlying our research, specific associations of our published data, and particularly our reconstruction of a demographic and political decline at Copán that extended well beyond A.D. 900. Braswell has incorrectly characterized the Copan Obsidian Hydration Dating Project’s methodology, and makes many factual errors in assessing the Copán data. In this paper the authors correct these errors, discuss basic issues of obsidian-hydration-dating methodology, and offer new data from Copán to evaluate the efficacy of hydration dating as a method and its potential future application for Mesoamerica as a whole.

The objective of this project is to demonstrate a high intensity glass melter, based on the submerged combustion melting technology. This melter will serve as the melting and homogenization section of a segmented, lower-capital cost, energy-efficient Next Generation Glass Melting System (NGMS). After this project, the melter will be ready to move toward commercial trials for some glasses needing little refining (fiberglass, etc.). For other glasses, a second project Phase or glass industry research is anticipated to develop the fining stage of the NGMS process.

This practice parameter describes the assessment and treatment of children and adolescents with attention-deficit/ hyperactivity disorder (ADHD) based on the current scientific evidence and clinical consensus of experts in the field. This parameter discusses the clinical evaluation for ADHD, comorbid conditions associated with ADHD, research on the etiology of the disorder, and psychopharmacological and psychosocial interventions for ADHD. J. Am. Acad. Child Adolesc. Psychiatry, 2007;46(7):894Y921. Key Words: attention-deficit/hyperactivity disorder, evaluation, treatment, practice parameter.

Electroconvulsive therapy (ECT) may be an effective treatment for adolescents with severe mood disorders and other Axis I psychiatric disorders when more conservative treatments have been unsuccessful. ECT may be considered when there is a lack of response to two or more trials of pharmacotherapy or when the severity of symptoms precludes waiting for a response to pharmacological treatment. The literature on ECT in adolescents, including studies and case reports, was reviewed and then integrated into clinically relevant guidelines for practitioners. Mood disorders have a high rate of response to ECT (75%–100%), whereas psychotic disorders have a lower response rate (50%–60%). Consent of the adolescent's legal guardian is mandatory, and the patient's consent or assent should be obtained. State legal guidelines and institutional guidelines must be followed. ECT techniques associated with the fewest adverse effects and greatest efficacy should be used. The presence of comorbid psychiatric disorder is not a contraindication. Systematic pretreatment and posttreatment evaluation, including symptom and cognitive assessment, is recommended.

Enuresis is a symptom that is frequently encountered in child psychiatric evaluations. Careful assessment is required to identify specific urologic, developmental, psychosocial, and sleep-related etiologies. For most children with enuresis, however, a specific etiology cannot be determined. Treatment then involves supportive approaches, conditioning with a urine alarm, or medications—imipramine or desmopressin acetate. The psychosocial consequences of the symptom must be recognized and addressed with sensitivity during the evaluation and treatment of enuresis.

This practice parameter describes treatment with stimulant medication. It uses an evidence-based medicine approach derived from a detailed literature review and expert consultation. Stimulant medications in clinical use include methylphenidate, dextroamphetamine, mixed salts of amphetamine, and pemoline. They carry U.S. Food and Drug Administration indications for the treatment of attention-deficit hyperactivity disorder.

Data on Late Archaic period (5000–1000 B.C.) agriculture and settlement in SE Mesoamerica and Lower Central America are reassessed in view of recent findings. Pollen data from Lake Tojoa in western Honduras are presented to support a re-synthesis of views on the development of food production systems in the region. Traditional interpretations of the cultural sequence suggest that the area was colonized by agriculturalists relatively late (1000 B.C.). Pollen from a core taken at Tojoa indicate that the region was inhabited by people practicing slash-and-burn maize horticulture by 3000 B.C., probably as a supplement to hunting and gathering systems. These and other data from throughout Middle America show that diffusion of maize cultivation from Mexico occurred earlier than expected to many areas of the Central American tropics.

In 1896–1897 George Byron Gordon investigated a series of caves in the Sesesmil River Valley, just north of the Late Classic Maya center of Copan, Honduras. His investigations revealed that at least one of these caves was utilized during the Preclassic period, and that several individuals had been cremated and interred in that cave. In 1983, as part of the Sesesmil settlement pattern survey of the Proyecto Arqueologico Copan, Phase II, the Sesesmil caves were revisited and two were test-excavated. This report summarizes the empirical findings of these more recent investigations, including pollen, skeletal, and ceramic analyses.