38 research outputs found
Cold Gas at High Redshift
We discuss the current observational and theoretical issues concerning cold
gas at high redshift and present simulations showing how a number of
observational issues can be resolved with planned future instrumentation.Comment: 13 page LaTeX requires crckapb.sty and psfig.sty, 9 compressed and
tarred postscript figures (410kB) available at
ftp://ftp.nfra.nl/pub/outgoing/rbraun/coldghiz/figs.tar.Z Complete compressed
postscript paper (475kB) available at
ftp://ftp.nfra.nl/pub/outgoing/rbraun/coldghiz/paper.ps.Z To appear in "Cold
Gas at High Redshift", Eds. M.Bremer et al. (Kluwer, Dordrecht
Canadian infants' nutrient intakes from complementary foods during the first year of life
<p>Abstract</p> <p>Background</p> <p>Complementary feeding is currently recommended after six months of age, when the nutrients in breast milk alone are no longer adequate to support growth. Few studies have examined macro- and micro-nutrient intakes from complementary foods (CF) only. Our purpose was to assess the sources and nutritional contribution of CF over the first year of life.</p> <p>Methods</p> <p>In July 2003, a cross-sectional survey was conducted on a nationally representative sample of mothers with infants aged three to 12 months. The survey was administered evenly across all regions of the country and included a four-day dietary record to assess infants' CF intakes in household (tablespoon) measures (breast milk and formula intakes excluded). Records from 2,663 infants were analyzed for nutrient and CF food intake according to 12 categories. Mean daily intakes for infants at each month of age from CF were pooled and compared to the Dietary Reference Intakes for the respective age range.</p> <p>Results</p> <p>At three months of age, 83% of infants were already consuming infant cereals. Fruits and vegetables were among the most common foods consumed by infants at all ages, while meats were least common at all ages except 12 months. Macro- and micro-nutrient intakes from CF generally increased with age. All mean nutrient intakes, except vitamin D and iron, met CF recommendations at seven to 12 months.</p> <p>Conclusions</p> <p>Complementary foods were introduced earlier than recommended. Although mean nutrient intakes from CF at six to 12 months appear to be adequate among Canadian infants, further attention to iron and vitamin D intakes and sources may be warranted.</p
The spatial scale of density-dependent growth and implications for dispersal from nests in juvenile Atlantic salmon
By dispersing from localized aggregations of recruits, individuals may obtain energetic benefits due to reduced experienced density. However, this will depend on the spatial scale over which individuals compete. Here, we quantify this scale for juvenile Atlantic salmon (Salmo salar) following emergence and dispersal from nests. A single nest was placed in each of ten replicate streams during winter, and information on the individual positions (±1 m) and the body sizes of the resulting young-of-the-year (YOY) juveniles was obtained by sampling during the summer. In six of the ten streams, model comparisons suggested that individual body size was most closely related to the density within a mean distance of 11 m (range 2–26 m). A link between body size and density on such a restricted spatial scale suggests that dispersal from nests confers energetic benefits that can counterbalance any survival costs. For the four remaining streams, which had a high abundance of trout and older salmon cohorts, no single spatial scale could best describe the relation between YOY density and body size. Energetic benefits of dispersal associated with reduced local density therefore appear to depend on the abundance of competing cohorts or species, which have spatial distributions that are less predictable in terms of distance from nests. Thus, given a trade-off between costs and benefits associated with dispersal, and variation in benefits among environments, we predict an evolving and/or phenotypically plastic growth rate threshold which determines when an individual decides to disperse from areas of high local density
A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067
Planets with radii between that of the Earth and Neptune (hereafter referred to as ‘sub-Neptunes’) are found in close-in orbits around more than half of all Sun-like stars 1,2. However, their composition, formation and evolution remain poorly understood 3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R ⊕ to 2.85R ⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres
Climate change effects on stream and river temperatures across the northwest U.S. from 1980–2009 and implications for salmonid fishes
A road map for designing and implementing a biological monitoring program
Designing and implementing natural resource monitoring is a challenging endeavor undertaken by many agencies, NGOs, and citizen groups worldwide. Yet many monitoring programs fail to deliver useful information for a variety of administrative (staffing, documentation, and funding) or technical (sampling design and data analysis) reasons. Programs risk failure if they lack a clear motivating problem or question, explicit objectives linked to this problem or question, and a comprehensive conceptual model of the system under study. Designers must consider what “success” looks like from a resource management perspective, how desired outcomes translate to appropriate attributes to monitor, and how they will be measured. All such efforts should be filtered through the question “Why is this important?” Failing to address these considerations will produce a program that fails to deliver the desired information. We addressed these issues through creation of a “road map” for designing and implementing a monitoring program, synthesizing multiple aspects of a monitoring program into a single, overarching framework. The road map emphasizes linkages among core decisions to ensure alignment of all components, from problem framing through technical details of data collection and analysis, to program administration. Following this framework will help avoid common pitfalls, keep projects on track and budgets realistic, and aid in program evaluations. The road map has proved useful for monitoring by individuals and teams, those planning new monitoring, and those reviewing existing monitoring and for staff with a wide range of technical and scientific skills
Integrated soil monitoring system for Internet of Thing (IOT) Applications
Spectroscopy is widely used in various field, including in agriculture to determine the contamination of soil in order to produce the good quality of food and to avoid the excessive use of fertilizer, thereby minimize the impact on the environment. However, the commercial and common method of soil spectroscopy has some limitation such as bulky in size, costly and non-real-time system. In this study, a high-speed electronic data acquisition via machine learning on FPGA is implemented to efficiently monitor the macronutrients level in soil, which would offer economic benefit. Our focus is particularly on recognizing exact photon level absorbed by soil by applying photon count processing techniques to monitor the macronutrient in soil samples. The hardware architectures on FPGA feature a 16-bit Kogge Stone adder to process the input signals from the sensing module, LED light control system, time frame setting system and data synchronization via cloud for Internet of Thing (IoT) application. The proposed photon counting system has been demonstrated using visible range wavelength of 630, 550, and 470 nm, respectively. In addition, the input photon signal can be varied from 0 to 200 kHz and frame time period of 10 ms produces the optimum counting result with the percentage variation from 0% to maximum of 15% as compared to the actual counting from the signal generated by the function generator. Apart from that, a real-time system for IoT application has been successfully tested
