957 resultados para Gajdusek, D. Carleton (Daniel Carleton), 1923-2008.
Resumo:
We present results on characterization of lasers with ultra-long cavity lengths up to 84km, the longest cavity ever reported. We have analyzed the mode structure, shape and width of the generated spectra, intensity fluctuations depending on length and intra-cavity power. The RF spectra exhibit an ultra-dense cavity mode structure (mode spacing is 1.2kHz for 84km), in which the width of the mode beating is proportional to the intra-cavity power while the optical spectra broaden with power according to the square-root law acquiring a specific shape with exponential wings. A model based on wave turbulence formalism has been developed to describe the observed effects.
Resumo:
Testing the idea that the process of forgiveness is intrinsically different across diverse relationships, this study examined the role of forgiveness in different family relationships. In 2 laboratory sessions 1 year apart, 114 families (each including 2 parents and 1 child) completed a new measure of family forgiveness and many individual-level, relationship-level, and family-level variables that have been previously linked with forgiveness. After validating the measure of family forgiveness in cross-sectional analyses, investigators performed longitudinal analyses to examine the role of forgiveness in each family relationship over the 1-year interval. Results indicated many important positive consequences of forgiveness on individual traits, aspects of each family relationship, and general family environment. However, there were also important asymmetries in associates of forgiveness across parent-child and parent-parent relationships, demonstrating the relationship-bound nature of forgiveness.
Resumo:
We present results on characterization of lasers with ultra-long cavity lengths up to 84km, the longest cavity ever reported. We have analyzed the mode structure, shape and width of the generated spectra, intensity fluctuations depending on length and intra-cavity power. The RF spectra exhibit an ultra-dense cavity mode structure (mode spacing is 1.2kHz for 84km), in which the width of the mode beating is proportional to the intra-cavity power while the optical spectra broaden with power according to the square-root law acquiring a specific shape with exponential wings. A model based on wave turbulence formalism has been developed to describe the observed effects.
Resumo:
The objective of this study is to investigate hydrocarbon species and amounts released by red mangrove foliage and determine if these quantities warrant future research on atmospheric chemical processing of these compounds. The field investigation took place during July 2001 at Key Largo, Florida Bay, Florida. Foliage still attached to plants was enclosed in cuvettes while air of known flow rates circulated around leaves to study, hydrocarbon emissions. Cuvette air samples underwent gas chromatographic analyses to determine species and amounts of hydrocarbons released by mangrove foliage. Red mangrove foliage emits isoprene and trace amounts of the monoterpenes of alpha-pinene, beta-pinene, camphene, and d-limonene. The mangrove flowers released these latter compounds in amounts ranging from 0.5 to 10 mg (monoterpene) per gram of dry biomass per hour. These fluxes are normalized to, the foliage temperature of 30 degreesC. When normalized to the foliage temperature of 30 degreesC and light levels of 1000 mumol m(-2) s(-1), isoprene emission rates as high as 0.092 +/- 0.109 mug (isoprene) per gram of dry biomass per hour were measured. Compared to terrestrial forest ecosystems, red mangroves are low isoprene emitters. During peak flowering periods in the summertime, however, red mangroves may emit sufficient amounts of monoterpenes to alter ground-level ozone concentrations and contribute to biogenic aerosol formation.
Resumo:
We examined periphyton along transects in five Everglades marshes and related compositional and functional aspects to phosphorus(P ) gradients caused by enriched inflows. Results were compared to those of a P-addition experiment in a pristine Everglades marsh. While the water total P (TP) concentration was not related to P load in the marshes or experiment the concentration of TP in periphyton was strongly correlated with the distance from the P source. Increased P concentration in periphyton was associated with a loss of biomass,p articularly of the calcifying mat-forming matrix, regardless of the growth form of the periphyton (epiphytic, floating,or epilithic). Diatom species composition was also strongly related to P availability, but the TP optima of many species varied among marshes. Enriched periphyton communities were found 14 km downstream of P inputs to one marsh that has been receiving enhanced P loads for decades, where other studies using different biotic indicators show negligible change in the same marsh. Although recovery trajectories are unknown, periphyton indicators should serve as excellent metrics for the progression or amelioration of P-related effects in the Everglades.
Resumo:
Wine reviews, such as those from Wine Spectator and other consumer publications, help drive wine sales. The researchers in this study utilized standardized wholesale “line pricing” from a major wholesale distributor in the Southwest to compare pricing to the ratings published by Wine Spectator and to determine whether there were any correlations among other key attributes of the wine. The study produced interesting results, including that the wholesale price and vintage of a wine are significant in the prediction of the wine’s rating.
Resumo:
Mutualistic symbioses between scleractinian corals and endosymbiotic dinoflagellates (Symbiodinium spp.) are the foundation of coral reef ecosystems. For many coral-algal symbioses, prolonged episodes of thermal stress damage the symbiont's photosynthetic capability, resulting in its expulsion from the host. Despite the link between photosynthetic competency and symbiont expulsion, little is known about the effect of thermal stress on the expression of photosystem genes in Symbiodinium. This study used real-time PCR to monitor the transcript abundance of two important photosynthetic reaction center genes, psbA(encoding the D1 protein of photosystem II) and psaA (encoding the P700 protein of photosystem I), in four cultured isolates (representing ITS2-types A13, A20, B1, and F2) and two in hospite Symbiodinium spp. within the coral Pocillopora spp. (ITS2-types C1b-c and D1). Both cultured and in hospite Symbiodinium samples were exposed to elevated temperatures (32°C) over a 7-day period and examined for changes in photochemistry and transcript abundance. Symbiodinium A13 and C1b-c (both thermally sensitive) demonstrated significant declines in both psbA and psaA during the thermal stress treatment, whereas the transcript levels of the other Symbiodinium types remained stable. The downregulation of both core photosystem genes could be the result of several different physiological mechanisms, but may ultimately limit repair rates of photosynthetic proteins, rendering some Symbiodinium spp. especially susceptible to thermal stress.
Resumo:
The aim of this study is to analyze the perception of European destinations through the eyes of Indian Bollywood film viewers to determine how perception is influenced by what is viewed in films. Researchers surveyed Indian consumers and collected 670 usable surveys. European destinations were divided into top five and bottom five destinations for Indian tourists, and data was then compared to world tourism statistics. Results indicate differences in destination preference among Bollywood viewers and worldwide tourist trends. Findings indicate that prominently featuring a landscape within Bollywood films can significantly impact Indians’ perception on the destinations’ image. European countries frequently portrayed in films have higher marks on multiple perception categories than those not featured in blockbuster Bollywood films.
Resumo:
The growth of spring break tourism in many destinations has become problematic, predominantly due to the excessive behaviour of college students. This paper examines residents’ attitudes toward spring break tourism in South Padre Island (located in Texas, USA) through the lens of community attachment. By understanding the attitudes of residents of the host communities, tourism planners and policy-makers can create policies to shape the character of tourism according to the residents’ needs. The findings suggest that, at this point in time, community residents perceive that the benefits of spring break tourism benefits exceed its’ costs. Also, the short and intense season of spring break tourism allows residents to better deal with social costs.
Resumo:
The development of models of marine ecosystems in the Southern Ocean is becoming increasingly important as a means of understanding and managing impacts such as exploitation and climate change. Collating data from disparate sources, and understanding biases or uncertainties inherent in those data, are important first steps for improving ecosystem models. This review focuses on seals that breed in ice habitats of the Southern Ocean (i.e. the crabeater seal, Lobodon carcinophaga; Ross seal, Ommatophoca rossii; leopard seal, Hydrurga leptonyx; and Weddell seal, Leptonychotes weddellii). Data on populations (abundance and trends in abundance), distribution and habitat use (movement, key habitat and environmental features) and foraging (diet) are summarised, and potential biases and uncertainties inherent in those data are identified and discussed. Spatial and temporal gaps in knowledge of the populations, habitats and diet of each species are also identified.
Resumo:
A sediment core from Reykjanes Ridge has been studied at 10- to 50-year time resolution to document variability of Holocene surface water conditions in the western North Atlantic and to evaluate effects of Holocene ice-rafting episodes. Diatom assemblages are converted to quantitative sea surface temperatures (SST) using three different transfer functions. Spectral and scale-space methods are also applied on the records to explore variability at different timescales. Diatom assemblage and SST records clearly show that decaying remnants of the Laurentide ice sheet strongly influenced early Holocene climate in the western North Atlantic. This overrode the predominance of Milankovitch forcing, which played a key role in the development of Holocene climate in the eastern North Atlantic and Nordic Seas. Superimposed on general Holocene climate change is high-frequency SST variability on the order of 1°-3°C. The record also documents climatic oscillations with 600- to 1000-, ~1500-, and 2500-year periodicities, with a time-dependent dominance of different periodicities through the Holocene; a clear change in variability occurred about 5 ka BP. The SST record also provides evidence for Holocene cooling events (HCE) that, in some cases, correlate to documented southward intrusions of ice into the North Atlantic.
Resumo:
Maintaining and enhancing living conditions in cities through a combination of physical planning and environmental management is a newly emerging focus of governments around the world. For example, local governments seek to insulate sensitive land uses such as residential areas from environmentally intrusive activities such as major transport facilities and manufacturing. Regional governments protect water quality and natural habitat by enforcing pollution controls and regulating the location of growth. Some national governments fund acquisition of strategically important sites, facilitate the renewal of brown fields, and even develop integrated environmental quality plans. This book provides recently developed and tested methods for assessing the strengths and weaknesses of planning and policy options. Several contributions focus on new substantive areas of concern in planning evaluation, including environmental justice and sustainable urban development. Applications of evaluation in several planning contexts are demonstrated, and special problems that these pose are assessed. Several chapters address how to communicate the process and results to several stakeholder groups, and how to engage these groups in the evaluation process. Each chapter employs a realworld case in practice, thus dealing with the complexity of applying planning evaluation, and providing practical advice useful in similar situations.