641 research outputs found
Information technology and computer science programs: How do we relate?
In this panel session, the relationship between computer science programs and information technology programs at universities that house both will be explored. People outside the computing disciplines often find the distinction between these programs confusing. The panelists, who have experience with both types of program, will discuss strategies for differentiating the programs in the eyes of administrators, for advising students into the correct program, and for maintaining focus and excellence in both computer science and information technology programs
Interactive learning online: Challenges and opportunities
Since the early 1990s online education and online learning systems have held the promise of increasing instructional productivity and reducing costs without sacrificing educational quality. There is no evidence to date that such promise has materialized. The impetus of the newest developments with free online courses to hundreds of thousands of students might drastically transform how we teach more and better with less. The innovation that prompted this panel is called Interactive Learning Online (ILO), and has the distinctive feature of highly interactive, machine-guided instruction that can be scaled to accommodate a large number of students who benefit from targeted and personalized learning. The panelists have experimented with online learning in different ways. Their perspectives will address challenges and opportunities with the adoption of ILO systems
Nasa's Land Remote Sensing Plans for the 1980's
Research since the launch of LANDSAT-1 has been primarily directed to the development of analysis techniques and to the conduct of applications studies designed to address resource information needs in the United States and in many other countries. The current measurement capabilities represented by MSS, TM, and SIR-A and B, coupled with the present level of remote sensing understanding and the state of knowledge in the discipline earth sciences, form the foundation for NASA's Land Processes Program. Science issues to be systematically addressed include: energy balance, hydrologic cycle, biogeochemical cycles, biological productivity, rock cycle, landscape development, geological and botanical associations, and land surface inventory, monitoring, and modeling. A global perspective is required for using remote sensing technology for problem solving or applications context. A successful model for this kind of activity involves joint research with a user entity where the user provides a test site and ground truth and NASA provides the remote sensing techniques to be tested
Integration-Valuation Nexus in Invasive Species Policy
This paper reviews recent work examining two topics of economic research vital for invasive species policy-integration and valuation. Integration requires bioeconomic models that blend invasive biology with economic circumstances and the feedback loops between the two systems. Valuation requires nonmarket valuation associated with human and environmental damages posed by invasive species. We argue for a second-level of integration in invasive species economics-valuation based on integration models. Policy prescriptions based on integration models need valuation work; valuation surveys need integration models-the two are complements. Valuation could be enhanced with integration in mind; integration could be made better with valuation in mind. An example from blending the two research areas is presented and its merits demonstrated.invasive species, integrated economic-ecological modeling, nonmarket valuation, Environmental Economics and Policy,
Magnitudes and sources of precipitation and dry deposition fluxes of indestrial and natural leads to the North Pacific at Enewetak
A total atmospheric Pb input flux of 7 ng Pb cm^−2 yr^−1 was measured in the North Pacific Easterlies at Enewetak. Parameters used to measure this flux were ratio of dry deposition flux to precipitation flux; Pb/^(210)Pb in precipitation and seawater; ^(210)Pb flux; washout factor; and Pb concentrations in air, rain, and dry deposition deposits. Relations among these parameters established at Enewetak were used to recompute and confirm previous estimates of lead fluxes to the oceans (ng Pb cm^−2 yr^−1) at the following locations: North Atlantic Westerlies, 170; North Pacific Westerlies, 50; and South Pacific Easterlies, 3. Prehistoric lead output fluxes to sediments (ng Pb cm^−2 yr^−1) at these locations have been previously measured and were 4 (Enewetak); 30 North Atlantic Westerlies; 3 North Pacific Westerlies; 4 South Pacific Easterlies. These data show that the rates of atmospheric inputs of lead to the oceans vary directly with variations in rates of upwind emissions of industrial lead from urban complexes on land. In the North Pacific and North Atlantic, present rates of atmospheric lead inputs are 10-fold greater than prehistoric outputs. In equatorial regions, present inputs and past outputs are more nearly equal. These observations disclose the effects of intense industrial atmospheric emissions of lead in the northern hemisphere westerlies which have overwhelmed prehistoric natural fluxes of lead to the oceans. The average concentration of lead in marine air at Enewetak is 170 pg m−3 and varies less than a factor of 2 from that mean. One to 15% of this lead comes from seaspray, while the remainder comes from sources on land. About 90% of the seaspray lead is industrial, while 80 to 99% of that originating from land sources is industrial. Concentrations of lead in rain at Enewetak range from 6 to 63 pg/g with a mean value of 28. The mean precipitation flux, corrected for recycled lead in sea salts, measured by four different methods, was 6 ng Pb cm^−2 yr^−1, while the net dry deposition flux measured on horizontal plastic plates was 0.6 ng Pb cm^−2 yr^−1. The total dry deposition flux measured was 6 ng cm^−2 yr^−1, but 90% of this lead came from recycled seaspray. Lead isotope tracers show that Japan is the major source of industrial lead at Enewetak during the dry season, while the United States is the major source during the wet season
Lead Precipitation Fluxes at Tropical Oceanic Sites Determined From ^(210)Pb Measurements
Concentrations of lead, ^(210)Pb, and ^(210)Po were measured in rain selected for least influence by local sources of contamination at several tropical and subtropical islands (Enewetak; Pigeon Key, Florida; and American Samoa) and shipboard stations (near Bermuda and Tahiti). Ratios expressed as ng Pb/dpm ^(210)Pb in rain were 250–900 for Pigeon Key (assuming 12% adsorption for ^(210)Pb and no adsorption for lead), depending on whether the air masses containing the analyzed rain came from the Caribbean or from the continent, respectively; about 390 for the northern Sargasso Sea downwind from emissions of industrial lead in North America; 65 for Enewetak, remote from continental emissions of industrial lead in the northern hemisphere; and 14 near Tahiti, a remote location in the southern hemisphere where industrial lead emissions to the atmosphere are much less than in the northern hemisphere. (The American Samoa sample yielded a higher ratio than Tahiti; the reason for this is not clear but may be due to local Pb sources.) The corresponding fluxes of lead to the oceans, based on measured or modeled ^(210)Pb precipitation fluxes, are about 4 ng Pb/cm^2y for Tahiti, 10 for Enewetak, and 270 for the Sargasso Sea site, and between 110 to 390 at Pigeon Key
The distribution of lead between sea salt dust, and lead-rich aerosols in the mid South Pacific easterlies at American Samoa
Aerosols in the South Pacific Easterlies have been sampled at American Samoa with a cascade impactor and analysed for Pb, Ba, K, Ca, Sr, and Rb by isotope dilution mass spectrometry using ultraclean procedures. Some 84% of the Pb was found in fine (≤ 0.5 μm) aerosols which were collected on the backup filter with an efficiency of only 33%. Sea salt and eroded terrestrial material (dust) containing 6% and <1% respectively, of the Pb (sea salt indexed by the metals K, Ca, Sr, and Rb and dust indexed by Ba) were collected on early stages of the impactor, although 65% of the dust, because of its larger size, was lost to surfaces of the rain shelter before reaching the impactor. The remaining 10% of the Pb was associated with plant leaf waxes of continental origin which produced Pb and Ba peaks on stage 4 (0.5 μ) of the impactor
An extension of the benefit segmentation base for the consumption of organic foods : a time perspective
Benefit segmentation is a long-standing marketing approach that emphasises the ‘what’ and ‘how’ dimensions of consumer benefits; that is, what benefits consumers perceive in product/service consumption, and how such benefits are perceived. This research proposes a fresh time-based approach to benefit segmentation – namely, focusing on the ‘when’ element or when in time benefits take effect. Drawing upon a survey of UK consumers, it explains and discusses consumption motivations through examining antecedents of temporally dominated benefits in application to organic food. Specifically, the study investigates why some consumers predominantly seek present-based benefits vis-à-vis future-based benefits or vice versa in organic food purchase and consumption behaviour. Using correlation and regression analyses, the research findings establish significant associations of level of involvement, prior knowledge level, and product usage level, and some association of time orientation with the temporally emphasised consumption benefits consumers ultimately pursue. Overall, the research highlights the added contribution of a time perspective in a benefit segmentation approach which can assist marketers in understanding better and communicating more effectively with consumers through drawing up consumer profiles based on when in time their dominantly pursued benefit for an offering is perceived to take effect
Insights from Amphioxus into the Evolution of Vertebrate Cartilage
Central to the story of vertebrate evolution is the origin of the vertebrate head, a problem difficult to approach using paleontology and comparative morphology due to a lack of unambiguous intermediate forms. Embryologically, much of the vertebrate head is derived from two ectodermal tissues, the neural crest and cranial placodes. Recent work in protochordates suggests the first chordates possessed migratory neural tube cells with some features of neural crest cells. However, it is unclear how and when these cells acquired the ability to form cellular cartilage, a cell type unique to vertebrates. It has been variously proposed that the neural crest acquired chondrogenic ability by recruiting proto-chondrogenic gene programs deployed in the neural tube, pharynx, and notochord. To test these hypotheses we examined the expression of 11 amphioxus orthologs of genes involved in neural crest chondrogenesis. Consistent with cellular cartilage as a vertebrate novelty, we find that no single amphioxus tissue co-expresses all or most of these genes. However, most are variously co-expressed in mesodermal derivatives. Our results suggest that neural crest-derived cartilage evolved by serial cooption of genes which functioned primitively in mesoderm
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