Showing papers by "University of New Mexico published in 2002"
TL;DR: Two novel scheduling algorithms for a bounded number of heterogeneous processors with an objective to simultaneously meet high performance and fast scheduling time are presented, called the Heterogeneous Earliest-Finish-Time (HEFT) algorithm and the Critical-Path-on-a-Processor (CPOP) algorithm.
Abstract: Efficient application scheduling is critical for achieving high performance in heterogeneous computing environments. The application scheduling problem has been shown to be NP-complete in general cases as well as in several restricted cases. Because of its key importance, this problem has been extensively studied and various algorithms have been proposed in the literature which are mainly for systems with homogeneous processors. Although there are a few algorithms in the literature for heterogeneous processors, they usually require significantly high scheduling costs and they may not deliver good quality schedules with lower costs. In this paper, we present two novel scheduling algorithms for a bounded number of heterogeneous processors with an objective to simultaneously meet high performance and fast scheduling time, which are called the Heterogeneous Earliest-Finish-Time (HEFT) algorithm and the Critical-Path-on-a-Processor (CPOP) algorithm. The HEFT algorithm selects the task with the highest upward rank value at each step and assigns the selected task to the processor, which minimizes its earliest finish time with an insertion-based approach. On the other hand, the CPOP algorithm uses the summation of upward and downward rank values for prioritizing tasks. Another difference is in the processor selection phase, which schedules the critical tasks onto the processor that minimizes the total execution time of the critical tasks. In order to provide a robust and unbiased comparison with the related work, a parametric graph generator was designed to generate weighted directed acyclic graphs with various characteristics. The comparison study, based on both randomly generated graphs and the graphs of some real applications, shows that our scheduling algorithms significantly surpass previous approaches in terms of both quality and cost of schedules, which are mainly presented with schedule length ratio, speedup, frequency of best results, and average scheduling time metrics.
2,961 citations
Emory University1, Research Triangle Park2, Case Western Reserve University3, National Institutes of Health4, University of Alabama at Birmingham5, Yale University6, Indiana University7, University of Cincinnati8, Boston Children's Hospital9, University of Texas Health Science Center at Houston10, Brown University11, University of Miami12, University of Tennessee Health Science Center13, Wayne State University14, University of Texas Southwestern Medical Center15, Stanford University16, University of New Mexico17
TL;DR: Infants who developed late-onset sepsis had a significantly prolonged hospital stay and were significantly more likely to die than those who were uninfected, especially if they were infected with Gram-negative organisms or fungi.
Abstract: Objective. Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 6956 VLBW (401–1500 g) neonates admitted to the clinical centers of the National Institute of Child Health and Human Development Neonatal Research Network over a 2-year period (1998–2000). Methods. The National Institute of Child Health and Human Development Neonatal Research Network maintains a prospective registry of all VLBW neonates admitted to participating centers within 14 days of birth. Expanded infection surveillance was added in 1998. Results. Of 6215 infants who survived beyond 3 days, 1313 (21%) had 1 or more episodes of blood culture-proven late-onset sepsis. The vast majority of infections (70%) were caused by Gram-positive organisms, with coagulase-negative staphylococci accounting for 48% of infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of late-onset sepsis included patent ductus arteriosus, prolonged ventilation, prolonged intravascular access, bronchopulmonary dysplasia, and necrotizing enterocolitis. Infants who developed late-onset sepsis had a significantly prolonged hospital stay (mean length of stay: 79 vs 60 days). They were significantly more likely to die than those who were uninfected (18% vs 7%), especially if they were infected with Gram-negative organisms (36%) or fungi (32%). Conclusions. Late-onset sepsis remains an important risk factor for death among VLBW preterm infants and for prolonged hospital stay among VLBW survivors. Strategies to reduce late-onset sepsis and its medical, social, and economic toll need to be addressed urgently.
2,102 citations
TL;DR: The results suggest that theta oscillations generated in frontal brain regions play an active role in memory maintenance.
Abstract: Recent theoretical work has suggested that brain oscillations in the theta band are involved in active maintenance and recall of working memory representations. To test this theoretical framework we recorded neuromagnetic responses from 10 subjects performing the Sternberg task. Subjects were required to retain a list of 1, 3, 5 or 7 visually presented digits during a 3-s retention period. During the retention period we observed ongoing frontal theta activity in the 7-8.5-Hz band recorded by sensors over frontal brain areas. The activity in the theta band increased parametrically with the number of items retained in working memory. A time-frequency analysis revealed that the task-dependent theta was present during the retention period and during memory scanning. Following the memory task the theta activity was reduced. These results suggest that theta oscillations generated in frontal brain regions play an active role in memory maintenance.
1,248 citations
TL;DR: Results demonstrate effective translocation of ultrafine elemental carbon particles to the liver by 1 d after inhalation exposure, and indicate input from ultrafine particles present in the GI tract needs to be considered as well.
Abstract: Studies with intravenously injected ultrafine particles have shown that the liver is the major organ of their uptake from the blood circulation. Measuring translocation of inhaled ultrafine particles to extrapulmonary organs via the blood compartment is hampered by methodological difficulties (i.e., label may come off, partial solubilization) and analytical limitations (measurement of very small amounts). The objective of our pilot study was to determine whether ultrafine elemental carbon particles translocate to the liver and other extrapulmonary organs following inhalation as singlet particles by rats. We generated ultrafine (13)C particles as an aerosol with count median diameters (CMDs) of 20-29 nm (GSD 1.7) using electric spark discharge of (13)C graphite electrodes in argon. Nine Fischer 344 rats were exposed to these particles for 6 h. in whole-body inhalation chambers at concentrations of 180 and 80 microg/m(3); 3 animals each were killed at 0.5, 18, and 24 h postexposure. Six unexposed rats served as controls. Lung lobes, liver, heart, brain, olfactory bulb, and kidney were excised, homogenized, and freeze-dried for analysis of the added (13)C by isotope ratio mass spectrometry. Organic (13)C was not detected in the (13)C particles. The (13)C retained in the lung at 0.5 h postexposure was about 70% less than predicted by rat deposition models for ultrafine particles, and did not change significantly during the 24-h postexposure period. Normalized to exposure concentration, the added (13)C per gram of lung on average in the postexposure period was approximately 9 ng/g organ/microg/m(3). Significant amounts of (13)C had accumulated in the liver by 0.5 h postinhalation only at the high exposure concentration, whereas by 18 and 24 h postexposure the (13)C amount of the livers of all exposed rats was about fivefold greater than the (13)C burden retained in the lung. No significant increase in (13)C was detected in the other organs which were examined. These results demonstrate effective translocation of ultrafine elemental carbon particles to the liver by 1 d after inhalation exposure. Translocation pathways include direct input into the blood compartment from ultrafine carbon particles deposited throughout the respiratory tract. However, since predictive particle deposition models indicate that respiratory tract deposits alone may not fully account for the hepatic (13)C burden, input from ultrafine particles present in the GI tract needs to be considered as well. Such translocation to blood and extrapulmonary tissues may well be different between ultrafine carbon and other insoluble (metal) ultrafine particles.
1,001 citations
TL;DR: A clear negative relationship between precipitation and changes in soil organic carbon and nitrogen content when grasslands were invaded by woody vegetation is found, with drier sites gaining, and wetter sites losing, soilorganic carbon.
Abstract: The invasion of woody vegetation into deserts, grasslands and savannas is generally thought to lead to an increase in the amount of carbon stored in those ecosystems. For this reason, shrub and forest expansion (for example, into grasslands) is also suggested to be a substantial, if uncertain, component of the terrestrial carbon sink1,2,3,4,5,6,7,8,9,10,11,12,13,14. Here we investigate woody plant invasion along a precipitation gradient (200 to 1,100 mm yr-1) by comparing carbon and nitrogen budgets and soil δ13C profiles between six pairs of adjacent grasslands, in which one of each pair was invaded by woody species 30 to 100 years ago. We found a clear negative relationship between precipitation and changes in soil organic carbon and nitrogen content when grasslands were invaded by woody vegetation, with drier sites gaining, and wetter sites losing, soil organic carbon. Losses of soil organic carbon at the wetter sites were substantial enough to offset increases in plant biomass carbon, suggesting that current land-based assessments may overestimate carbon sinks. Assessments relying on carbon stored from woody plant invasions to balance emissions may therefore be incorrect.
952 citations
TL;DR: A broad and flexible perspective on ecological restoration of Southwestern (U.S.) ponderosa pine forests has been discussed in this article, where the authors suggest principles for ecologically sound restoration that immediately reduce crown fire risk and incrementally return natural variability and resilience to Southwestern forests, and present ecological perspectives on several forest restoration approaches.
Abstract: The purpose of this paper is to promote a broad and flexible perspective on ecological restoration of Southwestern (U.S.) ponderosa pine forests. Ponderosa pine forests in the region have been radically altered by Euro-American land uses, including livestock grazing, fire suppression, and logging. Dense thickets of young trees now abound, old- growth and biodiversity have declined, and human and ecological communities are in- creasingly vulnerable to destructive crown fires. A consensus has emerged that it is urgent to restore more natural conditions to these forests. Efforts to restore Southwestern forests will require extensive projects employing varying combinations of young-tree thinning and reintroduction of low-intensity fires. Treatments must be flexible enough to recognize and accommodate: high levels of natural heterogeneity; dynamic ecosystems; wildlife and other biodiversity considerations; scientific uncertainty; and the challenges of on-the-ground im- plementation. Ecological restoration should reset ecosystem trends toward an envelope of ''natural variability,'' including the reestablishment of natural processes. Reconstructed historic reference conditions are best used as general guides rather than rigid restoration prescriptions. In the long term, the best way to align forest conditions to track ongoing climate changes is to restore fire, which naturally correlates with current climate. Some stands need substantial structural manipulation (thinning) before fire can safely be reintro- duced. In other areas, such as large wilderness and roadless areas, fire alone may suffice as the main tool of ecological restoration, recreating the natural interaction of structure and process. Impatience, overreaction to crown fire risks, extractive economics, or hubris could lead to widespread application of highly intrusive treatments that may further damage forest ecosystems. Investments in research and monitoring of restoration treatments are essential to refine restoration methods. We support the development and implementation of a diverse range of scientifically viable restoration approaches in these forests, suggest principles for ecologically sound restoration that immediately reduce crown fire risk and incrementally return natural variability and resilience to Southwestern forests, and present ecological perspectives on several forest restoration approaches.
936 citations
TL;DR: The present paper draws on the diffusion of innovations model to derive a series of strategies for speeding up the spread and implementation of new ideas in preventing addiction.
933 citations
University of Arizona1, Los Alamos National Laboratory2, Cornell University3, Max Planck Society4, Computer Sciences Corporation5, University of New Mexico6, The Catholic University of America7, University of California, San Diego8, Victoria University of Wellington9, California Institute of Technology10, Space Research Institute11, Goddard Space Flight Center12, University of Hawaii13
TL;DR: The Gamma-Ray Spectrometer on the Mars Odyssey has identified two regions near the poles that are enriched in hydrogen, and it is suggested that the host of the hydrogen in the subsurface layer is ice, which constitutes 35 ± 15% of the layer by weight.
Abstract: Using the Gamma-Ray Spectrometer on the Mars Odyssey, we have identified two regions near the poles that are enriched in hydrogen. The data indicate the presence of a subsurface layer enriched in hydrogen overlain by a hydrogen-poor layer. The thickness of the upper layer decreases with decreasing distance to the pole, ranging from a column density of about 150 grams per square centimeter at -42 degrees latitude to about 40 grams per square centimeter at -77 degrees. The hydrogen-rich regions correlate with regions of predicted ice stability. We suggest that the host of the hydrogen in the subsurface layer is ice, which constitutes 35 +/- 15% of the layer by weight.
916 citations
TL;DR: A general model is derived, based on first principles of allometry and biochemical kinetics, that predicts the time of ontogenetic development as a function of body mass and temperature, and suggests a general definition of biological time that is approximately invariant and common to all organisms.
Abstract: Body size and temperature are the two most important variables affecting nearly all biological rates and times. The relationship of size and temperature to development is of particular interest, because during ontogeny size changes and temperature often varies. Here we derive a general model, based on first principles of allometry and biochemical kinetics, that predicts the time of ontogenetic development as a function of body mass and temperature. The model fits embryonic development times spanning a wide range of egg sizes and incubation temperatures for birds and aquatic ectotherms (fish, amphibians, aquatic insects and zooplankton). The model also describes nearly 75% of the variation in post-embryonic development among a diverse sample of zooplankton. The remaining variation is partially explained by stoichiometry, specifically the whole-body carbon to phosphorus ratio. Development in other animals at other life stages is also described by this model. These results suggest a general definition of biological time that is approximately invariant and common to all organisms.
841 citations
TL;DR: Empirically the structure of this network of connections between individuals over which the virus spreads is investigated using data drawn from a large computer installation, and the implications for the understanding and prevention of computer virus epidemics are discussed.
Abstract: Many computer viruses spread via electronic mail, making use of computer users' email address books as a source for email addresses of new victims. These address books form a directed social network of connections between individuals over which the virus spreads. Here we investigate empirically the structure of this network using data drawn from a large computer installation, and discuss the implications of this structure for the understanding and prevention of computer virus epidemics.
808 citations
TL;DR: Understanding their expression in various CNS insults will allow for the use of MMP inhibitors in the treatment of neurological disorders, and hydroxymate‐based compounds have been shown to reduce injury in experimental allergic encephalomyelitis, experimental allergic neuritis, cerebral ischemia, intracerebral hemorrhage, and viral and bacterial infections.
Abstract: Matrix metalloproteinases (MMPs) are a gene family of neutral proteases that are important in normal development, wound healing, and a wide variety of pathological processes, including the spread of metastatic cancer cells, arthritic destruction of joints, atherosclerosis, and neuroinflammation. In the central nervous system (CNS), MMPs have been shown to degrade components of the basal lamina, leading to disruption of the blood-brain barrier (BBB), and to contribute to the neuroinflammatory response in many neurological diseases. Brain cells express both constitutive and inducible MMPs in response to cellular stress. MMPs are tightly regulated to avoid unwanted proteolysis. Secreted as inactive enzymes, the MMPs require activation by other proteases and free radicals. The MMPs are part of a larger class of metalloproteinases (MPs), which includes the recently discovered ADAMs (a disintegrin and metalloproteinase domain) and ADAMTS (a disintegrin and metalloproteinase thrombospondin) families. MPs have complex roles at the cell surface and within the extracellular matrix. At the cell surface, they act as sheddases, releasing growth factors, death receptors, and death-inducing ligands, making them important in cell survival and death. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors that regulate the activity of the MMPs. Synthetic inhibitors have been developed for the treatment of arthritis and cancer. These hydroxymate-based compounds have been shown to reduce injury in experimental allergic encephalomyelitis (EAE), experimental allergic neuritis (EAN), cerebral ischemia, intracerebral hemorrhage, and viral and bacterial infections. MPs have both beneficial and detrimental roles; understanding their expression in various CNS insults will allow for the use of MMP inhibitors in the treatment of neurological disorders.
TL;DR: In this paper, the authors show that the average energy flux of populations is temperature invariant and derive a model that quantitatively predicts how species diversity increases with environmental temperature, supported by data for terrestrial, freshwater, and marine taxa along latitudinal and elevational gradients.
Abstract: The latitudinal gradient of increasing biodiversity from poles to equator is one of the most prominent but least understood features of life on Earth. Here we show that species diversity can be predicted from the biochemical kinetics of metabolism. We first demonstrate that the average energy flux of populations is temperature invariant. We then derive a model that quantitatively predicts how species diversity increases with environmental temperature. Predictions are supported by data for terrestrial, freshwater, and marine taxa along latitudinal and elevational gradients. These results establish a thermodynamic basis for the regulation of species diversity and the organization of ecological communities.
TL;DR: Methodological quality of studies was significantly but modestly correlated with the reporting of a specific effect of treatment, and strongest evidence of efficacy was found for brief interventions, social skills training, the community reinforcement approach, behavior contracting, behavioral marital therapy and case management.
Abstract: Aim A 3-year update with 59 new controlled trials is provided for the ongoing Mesa Grande project reviewing clinical trials of treatments for alcohol use disorders. The project summarizes the current evidence for various treatment approaches, weighting findings differentially according to the methodological strength of each study.
Design The review includes 361 controlled studies that (1) evaluated at least one treatment for alcohol use disorders, (2) compared it with an alternative condition (such as a control group, a placebo, a brief intervention or an alternative treatment), (3) used a procedure designed to create equivalent groups before treatment and (4) reported at least one outcome measure of drinking or alcohol-related consequences. Studies were rated by two reviewers on 12 methodological criteria, and outcome logic was analyzed for the specific treatment modalities tested.
Findings Methodological quality of studies was significantly but modestly correlated with the reporting of a specific effect of treatment. Among psychosocial treatments, strongest evidence of efficacy was found for brief interventions, social skills training, the community reinforcement approach, behavior contracting, behavioral marital therapy and case management. For the first time, two pharmacotherapies also appeared among the most strongly supported approaches: opiate antagonists (naltrexone, nalmefene) and acamprosate. Least supported were methods designed to educate, confront, shock or foster insight regarding the nature and causes of alcoholism.
Conclusions Treatment methods differ substantially in apparent efficacy. It would be sensible to consider these differences in designing and funding treatment programs.
TL;DR: In this article, the role of animation in multimedia learning is examined, including multimedia instructional messages and microworld games, and a cognitive theory of multimedia learning, which has yielded seven principles for the use of animation for multimedia instruction.
Abstract: How can animation be used to promote learner understanding of scientific and mathematical explanations? In this review, we examine the role of animation in multimedia learning (including multimedia instructional messages and microworld games), present a cognitive theory of multimedia learning, and summarize our program of research, which has yielded seven principles for the use of animation in multimedia instruction. These include the multimedia principle (present animation and narration rather than narration alone), spatial contiguity principle (present on-screen text near rather than far from corresponding animation), temporal contiguity principle (present corresponding animation and narration simultaneously rather than successively), coherence principle (exclude extraneous words, sounds, and video), modality principle (present animation and narration rather than animation and onscreen text), redundancy principle (present animation and narration rather than animation, narration, and on-screen text), and personalization principle (present words in conversational rather than formal style). Animation can promote learner understanding when used in ways that are consistent with the cognitive theory of multimedia learning.
Emory University1, RTI International2, Case Western Reserve University3, National Institutes of Health4, University of Alabama5, Yale University6, Indiana University – Purdue University Indianapolis7, University of Cincinnati8, Harvard University9, University of Texas at Austin10, University of Miami11, University of Tennessee Health Science Center12, Wayne State University13, Stanford University14, University of New Mexico15
TL;DR: Early-onset sepsis remains an uncommon but potentially lethal problem among very-low-birth-weight infants, and the change in pathogens over time from predominantly gram-positive to predominantly Gram-negative requires confirmation by ongoing surveillance.
Abstract: Background It is uncertain whether the rates and causes of early-onset sepsis (that occurring within 72 hours after birth) among very-low-birth-weight infants have changed in recent years, since antibiotics have begun to be used more widely during labor and delivery. Methods We studied 5447 very-low-birth-weight infants (those weighing between 401 and 1500 g) born at centers of the Neonatal Research Network of the National Institute of Child Health and Human Development between 1998 and 2000 who had at least one blood culture in the first three days of life and compared them with 7606 very-low-birth-weight infants born at centers in the network between 1991 and 1993. Results Early-onset sepsis (as confirmed by positive blood cultures) was present in 84 infants in the more recent birth cohort (1.5 percent). As compared with the earlier birth cohort, there was a marked reduction in group B streptococcal sepsis (from 5.9 to 1.7 per 1000 live births of infants weighing 401 to 1500 g, P<0.001) and an increase ...
Johns Hopkins University1, University of Texas at Austin2, United States Army Medical Research Institute of Infectious Diseases3, Centers for Disease Control and Prevention4, University of New Mexico5, Food and Drug Administration6, United States Department of Health and Human Services7, National Institutes of Health8, Nuclear Threat Initiative9, New York State Department of Health10, University of Minnesota11
TL;DR: Weapons disseminating a number of HFVs could cause an outbreak of an undifferentiated febrile illness 2 to 21 days later, associated with clinical manifestations that could include rash, hemorrhagic diathesis, and shock.
Abstract: ObjectiveTo develop consensus-based recommendations for measures to be taken
by medical and public health professionals if hemorrhagic fever viruses (HFVs)
are used as biological weapons against a civilian populationParticipantsThe Working Group on Civilian Biodefense included 26 representatives
from academic medical centers, public health, military services, governmental
agencies, and other emergency management institutionsEvidenceMEDLINE was searched from January 1966 to January 2002 Retrieved references,
relevant material published prior to 1966, and additional sources identified
by participants were reviewedConsensus ProcessThree formal drafts of the statement that synthesized information obtained
in the evidence-gathering process were reviewed by the working group Each
draft incorporated comments and judgments of the members All members approved
the final draftConclusionsWeapons disseminating a number of HFVs could cause an outbreak of an
undifferentiated febrile illness 2 to 21 days later, associated with clinical
manifestations that could include rash, hemorrhagic diathesis, and shock
The mode of transmission and clinical course would vary depending on the specific
pathogen Diagnosis may be delayed given clinicians' unfamiliarity with these
diseases, heterogeneous clinical presentation within an infected cohort, and
lack of widely available diagnostic tests Initiation of ribavirin therapy
in the early phases of illness may be useful in treatment of some of these
viruses, although extensive experience is lacking There are no licensed vaccines
to treat the diseases caused by HFVs
TL;DR: The majority of articles about refugee trauma or health are either descriptive or include quantitative data from instruments that have limited or untested validity and reliability in refugees, highlighting primary limitations to accurate measurement in refugee research.
Abstract: ContextRefugees experience multiple traumatic events and have significant associated
health problems, but data about refugee trauma and health status are often
conflicting and difficult to interpret.ObjectivesTo assess the characteristics of the literature on refugee trauma and
health, to identify and evaluate instruments used to measure refugee trauma
and health status, and to recommend improvements.Data SourcesMEDLINE, PsychInfo, Health and PsychoSocial Instruments, CINAHL, and
Cochrane Systematic Reviews (searched through OVID from the inception of each
database to October 2001), and the New Mexico Refugee Project database.Study SelectionKey terms and combination operators were applied to identify English-language
publications evaluating measurement of refugee trauma and/or health status.Data ExtractionInformation extracted for each article included author; year of publication;
primary focus; type (empirical, review, or descriptive); and type/name and
properties of instrument(s) included. Articles were excluded from further
analyses if they were review or descriptive, were not primarily about refugee
health status or trauma, or were only about infectious diseases. Instruments
were then evaluated according to 5 criteria (purpose, construct definition,
design, developmental process, reliability and validity) as described in the
published literature.Data SynthesisOf 394 publications identified, 183 were included for further analyses
of their characteristics; 91 (49.7%) included quantitative data but did not
evaluate measurement properties of instruments used in refugee research, 78
(42.6%) reported on statistical relationships between measures (presuming
validity), and 14 (7.7%) were only about statistical properties of instruments.
In these 183 publications, 125 different instruments were used; of these,
12 were developed in refugee research. None of these instruments fully met
all 5 evaluation criteria, 3 met 4 criteria, and 5 met only 1 of the criteria.
Another 8 standard instruments were designed and developed in nonrefugee populations
but adapted for use in refugee research; of these, 2 met all 5 criteria and
6 met 4 criteria.ConclusionsThe majority of articles about refugee trauma or health are either descriptive
or include quantitative data from instruments that have limited or untested
validity and reliability in refugees. Primary limitations to accurate measurement
in refugee research are the lack of theoretical bases to instruments and inattention
to using and reporting sound measurement principles.
TL;DR: It is shown that for sub-Saharan African birds, the apparent role of productivity diminishes with decreasing range size, whereas the significance of topographic heterogeneity increases, and the relative importance of geometric constraints from the continental edge is moderate.
Abstract: Geographic patterns in species richness are mainly based on wide-ranging species because their larger number of distribution records has a disproportionate contribution to the species richness counts. Here we demonstrate how this effect strongly influences our understanding of what determines species richness. Using both conventional and spatial regression models, we show that for sub-Saharan African birds, the apparent role of productivity diminishes with decreasing range size, whereas the significance of topographic heterogeneity increases. The relative importance of geometric constraints from the continental edge is moderate. Our findings highlight the failure of traditional species richness models to account for narrow-ranging species that frequently are also threatened.
TL;DR: In this article, the integrity of freshwater ecosystems depends upon adequate quantity, quality, timing, and temporal variability of water flow, and these attributes impart relatively unique characteristics of productivity and biodiversity to each ecosystem.
Abstract: Human society has used freshwater from rivers, lakes, groundwater, and wetlands for many different urban, agricultural, and industrial activities, but in doing so has overlooked its value in supporting ecosystems. Freshwater is vital to human life and societal well-being, and thus its utilization for consumption, irrigation, and transport has long taken precedence over other commodities and services provided by freshwater ecosystems. However, there is growing recognition that functionally intact and biologically complex aquatic ecosystems provide many economically valuable services and long-term benefits to society. The short-term benefits include ecosystem goods and services, such as food supply, flood control, purification of human and industrial wastes, and habitat for plant and animal life—and these are costly, if not impossible, to replace. Long-term benefits include the sustained provision of those goods and services, as well as the adaptive capacity of aquatic ecosystems to respond to future environmental alterations, such as climate change. Thus, maintenance of the processes and properties that support freshwater ecosystem integrity should be included in debates over sustainable water resource allocation.
The purpose of this report is to explain how the integrity of freshwater ecosystems depends upon adequate quantity, quality, timing, and temporal variability of water flow. Defining these requirements in a comprehensive but general manner provides a better foundation for their inclusion in current and future debates about allocation of water resources. In this way the needs of freshwater ecosystems can be legitimately recognized and addressed. We also recommend ways in which freshwater ecosystems can be protected, maintained, and restored.
Freshwater ecosystem structure and function are tightly linked to the watershed or catchment of which they are a part. Because riverine networks, lakes, wetlands, and their connecting groundwaters, are literally the “sinks” into which landscapes drain, they are greatly influenced by terrestrial processes, including many human uses or modifications of land and water. Freshwater ecosystems, whether lakes, wetlands, or rivers, have specific requirements in terms of quantity, quality, and seasonality of their water supplies. Sustainability normally requires these systems to fluctuate within a natural range of variation. Flow regime, sediment and organic matter inputs, thermal and light characteristics, chemical and nutrient characteristics, and biotic assemblages are fundamental defining attributes of freshwater ecosystems. These attributes impart relatively unique characteristics of productivity and biodiversity to each ecosystem. The natural range of variation in each of these attributes is critical to maintaining the integrity and dynamic potential of aquatic ecosystems; therefore, management should allow for dynamic change. Piecemeal approaches cannot solve the problems confronting freshwater ecosystems.
Scientific definitions of the requirements to protect and maintain aquatic ecosystems are necessary but insufficient for establishing the appropriate distribution between societal and ecosystem water needs. For scientific knowledge to be implemented science must be connected to a political agenda for sustainable development. We offer these recommendations as a beginning to redress how water is viewed and managed in the United States: (1) Frame national and regional water management policies to explicitly incorporate freshwater ecosystem needs, particularly those related to naturally variable flow regimes and to the linking of water quality with water quantity; (2) Define water resources to include watersheds, so that freshwaters are viewed within a landscape, or systems context; (3) Increase communication and education across disciplines, especially among engineers, hydrologists, economists, and ecologists to facilitate an integrated view of freshwater resources; (4) Increase restoration efforts, using well-grounded ecological principles as guidelines; (5) Maintain and protect the remaining freshwater ecosystems that have high integrity; and (6) Recognize the dependence of human society on naturally functioning ecosystems.
University of California, San Francisco1, National Institutes of Health2, University of Washington3, Group Health Cooperative4, University of Vermont5, University of Nevada, Reno6, University of North Carolina at Chapel Hill7, University of New Mexico8, Dartmouth College9, Fred Hutchinson Cancer Research Center10
TL;DR: Overall, approximately 1 in every 1300 screening mammography examinations leads to a diagnosis of DCIS, and the clinical significance of screen-detected DCIS needs further investigation.
Abstract: Background: With the large number of women having mammography—an estimated 28.4 million U.S. women aged 40 years and older in 1998—the percentage of cancers detected as ductal carcinoma in situ (DCIS), which has an uncertain prognosis, has increased. We pooled data from seven regional mammography registries to determine the percentage of mammographically detected cancers that are DCIS and the rate of DCIS per 1000 mammograms. Methods: We analyzed data on 653 833 mammograms from 540 738 women between 40 and 84 years of age who underwent screening mammography at facilities participating in the National Cancer Institute’s Breast Cancer Surveillance Consortium (BCSC) throughout 1996 and 1997. Mammography results were linked to population-based cancer and pathology registries. We calculated the percentage of screen-detected breast cancers that were DCIS, the rate of screen-detected DCIS per 1000 mammograms by age and by previous mammography status, and the sensitivity of screening mammography. Statistical tests were two-sided. Results: A total of 3266 cases of breast cancer were identified, 591 DCIS and 2675 invasive breast cancer. The percentage of screendetected breast cancers that were DCIS decreased with age (from 28.2% [95% confidence interval (CI) = 23.9% to 32.5%] for women aged 40–49 years to 16.0% [95% CI = 13.3% to 18.7%] for women aged 70–84 years). However, the rate of screen-detected DCIS cases per 1000 mammograms increased with age (from 0.56 [95% CI = 0.41 to 0.70] for women aged 40–49 years to 1.07 [95% CI = 0.87 to 1.27] for women aged 70–84 years). Sensitivity of screening mammography in all age groups combined was higher for detecting DCIS (86.0% [95% CI = 83.2% to 88.8%]) than it was for detecting invasive breast cancer (75.1% [95% CI = 73.5% to 76.8%]). Conclusions: Overall, approximately 1 in every 1300 screening mammography examinations leads to a diagnosis of DCIS. Given uncertainty about the natural history of DCIS, the clinical significance of screen-detected DCIS needs further investigation. [J Natl Cancer Inst 2002;94: 1546–54]
TL;DR: Described examination of selected studies indicates that among women, childhood abuse is likely to be a factor in the development of SUPs, but that the relationship is mediated by other psychiatric conditions, such as anxiety and depressive disorders.
TL;DR: Marty and Jambon as discussed by the authors derived an estimate of the CO2 flux from the (upper) mantle by combining estimates of the 3He flux at mid-ocean ridges (MOR) with measurements of CO2/3He ratio in oceanic basalts.
Abstract: Volatiles are lost from the Earth’s mantle to the atmosphere, hydrosphere and crust through a combination of subaerial and submarine volcanic and magmatic activity. These volatiles can be primordial in origin, trapped in the mantle since planetary accretion, produced in situ, or they may be recycled—re-injected into the mantle via material originally at the surface through the subduction process. Quantifying the absolute and relative contributions of these various volatile sources bears fundamental information on a number of issues in the Earth Sciences ranging from the evolution of the atmosphere and hydrosphere to the nature and scale of chemical heterogeneity in the Earth’s mantle.
Noble gases have a pivotal role to play in addressing the volatile mass balance between the Earth’s interior and exterior reservoirs. The primordial isotope 3He provides an unambiguous measure of the juvenile volatile flux from the mantle (Craig et al. 1975). As such, it provides a means to calibrate other volatiles of geological and geochemical interest. A prime example is the CO2 flux at mid-ocean ridges (MOR): by combining estimates of the 3He flux at MOR with measurements of the CO2/3He ratio in oceanic basalts, Marty and Jambon (1987) derived an estimate of the CO2 flux from the (upper) mantle.
The approach of using ratios (involving noble gas isotopes) has also been extended to island arcs. Marty et al. (1989) found significantly higher CO2/3He ratios in arc-related geothermal fluids than observed at mid-ocean ridges, consistent with addition of slab-derived CO2 to the mantle wedge. Sano and Williams (1996) scaled the CO2 flux to 3He, showing that the output of CO2 at subduction zones was comparable in magnitude to that at spreading ridges. Therefore, for CO2 at least, subduction zones also …
TL;DR: In this paper, a review of the literature on supported Pd catalysts for combustion of methane is presented, taking into consideration the oxidation/reduction mechanisms for supported palladium, poisoning, restructuring, the form of oxygen on the surface, methane activation over Pd and PdO phases, and transient behavior.
Abstract: Palladium-based catalysts are widely applied in exhaust catalytic converter and catalytic combustion systems. The mechanism for methane oxidation on a Pd-based catalyst is complex. Catalyst activity is influenced by variations in the process pressure and temperature, by the gas mixture composition, by the type of support and various additives, and by pretreatment under reducing or oxidizing atmospheres. In this paper, we review the literature on supported Pd catalysts for combustion of methane. The mechanisms involved are discussed taking into consideration the oxidation/reduction mechanisms for supported palladium, poisoning, restructuring, the form of oxygen on the surface, methane activation over Pd and PdO phases, and transient behavior. Our review helps explain the array of experimental results reported in the literature.
TL;DR: The results suggest that species richness may be increasing at subglobal scales for many groups and that future research should address what consequences this may have on ecological processes.
Abstract: Species richness is decreasing at a global scale. At subglobal scales, that is, within any defined area less extensive than the globe, species richness will increase when the number of nonnative species becoming naturalized is greater than the number of native species becoming extinct. Determining whether this has occurred is usually difficult because detailed records of species extinctions and naturalizations are rare; these records often exist, however, for oceanic islands. Here we show that species richness on oceanic islands has remained relatively unchanged for land birds, with the number of naturalizations being roughly equal to the number of extinctions, and has increased dramatically for vascular plants, with the number of naturalizations greatly exceeding the number of extinctions. In fact, for plants, the net number of species on islands has approximately doubled. We show further that these patterns are robust to differences in the history of human occupation of these islands and to th...
TL;DR: This work shows that the neural t-SNARE (target-membrane-associated–soluble N-ethylmaleimide fusion protein attachment protein (SNAP) receptor SNAP-25 is not required for nerve growth or stimulus-independent neurotransmitter release, but is essential for evoked synaptic transmission at neuromuscular junctions and central synapses.
Abstract: Axon outgrowth during development and neurotransmitter release depends on exocytotic mechanisms, although what protein machinery is common to or differentiates these processes remains unclear. Here we show that the neural t-SNARE (target-membrane-associated-soluble N-ethylmaleimide fusion protein attachment protein (SNAP) receptor) SNAP-25 is not required for nerve growth or stimulus-independent neurotransmitter release, but is essential for evoked synaptic transmission at neuromuscular junctions and central synapses. These results demonstrate that the development of neurotransmission requires the recruitment of a specialized SNARE core complex to meet the demands of regulated exocytosis.
TL;DR: An alternate exemplar model that can account for lexical variation in phonetic detail is outlined here, which predicts that the frequency with which words are used in the contexts for change will affect how readily the word undergoes a change in progress.
Abstract: The literature on frequency effects in lexical diffusion shows that even phonetically gradual changes that in some cases are destined to be lexically regular show lexical diffusion while they are in progress. Change that is both phonetically and lexically gradual presents a serious challenge to theories with phonemic underlying forms. An alternate exemplar model that can account for lexical variation in phonetic detail is outlined here. This model predicts that the frequency with which words are used in the contexts for change will affect how readily the word undergoes a change in progress. This prediction is tested on data from /t, d/ deletion in American English. Finally, the effect of bound morphemes on the diffusion of a sound change is examined. The data suggest that instances of a bound morpheme can affect the rate of change for that morpheme overall.
TL;DR: It is suggested that developing an adequate epidemiologic case definition based on current diagnostic criteria is possible and is a prerequisite for further developing the epidemiology of ADHD and Population-based Epidemiologic studies may shed important new light on how to understand ADHD.
Abstract: Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood. However, basic information about how the prevalence of ADHD varies by race/ethnicity, sex, age, and socio-economic status remains poorly described. One reason is that difficulties in the diagnosis of ADHD have translated into difficulties developing an adequate case definition for epidemiologic studies. Diagnosis depends heavily on parent and teacher reports; no laboratory tests reliably predict ADHD. Prevalence estimates of ADHD are sensitive to who is asked what, and how information is combined. Consequently, recent systematic reviews report ADHD prevalence estimates as wide as 2%-18%. The diagnosis of ADHD is complicated by the frequent occurrence of comorbid conditions such as learning disability, conduct disorder, and anxiety disorder. Symptoms of these conditions may also mimic ADHD. Nevertheless, we suggest that developing an adequate epidemiologic case definition based on current diagnostic criteria is possible and is a prerequisite for further developing the epidemiology of ADHD. The etiology of ADHD is not known but recent studies suggest both a strong genetic link as well as environmental factors such as history of preterm delivery and perhaps, maternal smoking during pregnancy. Children and teenagers with ADHD use health and mental health services more often than their peers and engage in more health threatening behaviors such as smoking, and alcohol and substance abuse. Better methods are needed for monitoring the prevalence and understanding the public health implications of ADHD. Stimulant medication is the treatment of choice for treating ADHD but psychosocial interventions may also be warranted if comordid disorders are present. The treatment of ADHD is controversial because of the high prevalence of medication treatment. Epidemiologic studies could clarify whether the patterns of ADHD diagnosis and treatment in community settings is appropriate. Population-based epidemiologic studies may shed important new light on how we understand ADHD, its natural history, its treatment and its consequences.
TL;DR: In the current health care environment, researchers are asked to share meaningful results with interdisciplinary professional audiences, concerned community members, students, policy makers, planners, and financial officers.
Abstract: In the current health care environment, researchers are asked to share meaningful results with interdisciplinary professional audiences, concerned community members, students, policy makers, planners, and financial officers. Emphasis is placed on effective health care outcomes and evidence, especially for underserved and vulnerable populations. Any research strategy that facilitates the clear, accurate communication of findings and voices will likely benefit groups targeted for intervention with scarce resources. In this example, matrix analysis contributes to the display, interpretation, pragmatic evaluation, and dissemination of findings in a study of rural elders. The author proposes matrix analysis as a strategy to advance knowledge and enhance the development of evidence in qualitative research.
TL;DR: The origins and migration of DCs to their sites of activity, their basic biology as antigen-presenting cells, their roles in important human diseases and, finally, selected strategies being pursued to harness their potent antigen-stimulating activity are addressed.
Abstract: Dendritic cells (DCs) are bone marrow-derived cells of both lymphoid and myeloid stem cell origin that populate all lymphoid organs including the thymus, spleen, and lymph nodes, as well as nearly all nonlymphoid tissues and organs. Although DCs are a moderately diverse set of cells, they all have potent antigen-presenting capacity for stimulating naive, memory, and effector T cells. DCs are members of the innate immune system in that they can respond to dangers in the host environment by immediately generating protective cytokines. Most important, immature DCs respond to danger signals in the microenvironment by maturing, i.e., differentiating, and acquiring the capacity to direct the development of primary immune responses appropriate to the type of danger perceived. The powerful adjuvant activity that DCs possess in stimulating specific CD4 and CD8 T cell responses has made them targets in vaccine development strategies for the prevention and treatment of infections, allograft reactions, allergic and autoimmune diseases, and cancer. This review addresses the origins and migration of DCs to their sites of activity, their basic biology as antigen-presenting cells, their roles in important human diseases and, finally, selected strategies being pursued to harness their potent antigen-stimulating activity.
TL;DR: A set of deoxyribozyme-based logic gates capable of generating any Boolean function, constructed through a modular design that combines molecular beacon stem-loops with hammerhead-type deoxy ribozymes, open the possibility of communication between various computation elements in solution.
Abstract: We report herein a set of deoxyribozyme-based logic gates capable of generating any Boolean function. We construct basic NOT and AND gates, followed by the more complex XOR gate. These gates were constructed through a modular design that combines molecular beacon stem-loops with hammerhead-type deoxyribozymes. Importantly, as the gates have oligonucleotides as both inputs and output, they open the possibility of communication between various computation elements in solution. The operation of these gates is conveniently connected to a fluorescent readout.