20,542 research outputs found
Remote Camera and Trapping Survey of the Deep-water Shrimps Heterocarpus laevigatus and H. ensifer and the Geryonid Crab Chaceon granulatus in Palau
Time-lapse remote photo-sequences at 73-700 m depth off Palau, Western Caroline Islands, show that the caridean shrimp Heterocarpus laevigatus tends to be a solitary animal, occurring below ~350 m, that gradually accumulates around bait sites over a prolonged period. A smaller speies, H. ensifer, tends to move erratically in swarms, appearing in large numbers in the upper part of its range (<250 m) during the evening crepuscular period and disappearing at dawn. Trapping and photsequence data indicate the depth range of H. ensifer (during daylight) is ~250-550 M, while H. laevigatus ranges from 350 m to at least 800 m, along with the geryonid crab Chaceon granulatus. Combined trapping for Heterocarpus laevigatus and Chaceon granulatus, using a three-chamber box-trap and extended soak times (48-72 hr), may be an appropriate technique for small-scale deep-water fisheries along forereef slopes of Indo-Pacific archipelagoes
On the Distribution and Fishery Potential of the Japanese Red Crab Chaceon granulatus in the Palauan Archipelago, Western Caroline Islands
A deep-water trapping survey in the Palauan archipelago, Western Caroline Islands, has revealed an abundance of the Japanese red crab, Chaceon granulatus. The recorded depth range (250-900 m) is similar to that of other geryonids, but the large numbers of females caught below 700 m is atypical. Mean yields in excess of 5 kg crabs plus 1 kg shrimp, Heterocarpus laevigatus, by-catch per trap-night were attainable at optimum depths. Chaceon granulatus is apparently a very large geryonid, with maximum weights of
2.02 kg and 1.51 kg recorded for male and female specimens, respectively. A range of body colors was observed: Orange-red shades appear to dominate the deeper waters (below 500 m) while yellow-tan colors are more abundant in the upper reaches.
Preliminary evidence suggests that Chaceon granulatus is highly marketable, and the infrastructure in Palau is such that crabs could either be marketed fresh locally or airfreighted to Japan as a quick-frozen product. The high post-trapping survival rates observed indicate that maintaining crabs in live-holding tanks may be a feasible option. The large catches and quality of deep-water crabs taken suggests that the Palauan population of Chaceon granulatus may be able to support a small-scale fishery. It is not yet known whether this population is unusually large or whether these findings typify the deep forereef fauna of the region
Summer snow extent heralding of the winter North Atlantic Oscillation
[1] Winter climate over the North Atlantic and European sector is modulated by the North Atlantic Oscillation (NAO). We find that the summer extent of snow cover over northern North America and northern Eurasia is linked significantly (p < 0.01) to the upcoming winter NAO state. Summers with high/low snow extent precede winters of low/high NAO index phase. We suggest the linkage arises from the summer snow-associated formation of anomalous longitudinal differences in surface air temperature with the subpolar North Atlantic. Our findings indicate the seasonal predictability of North Atlantic winter climate may be higher and extend to longer leads than thought previously
Half-time and high-speed running in the second half of soccer
This study investigated if the quantity of high-speed running (movements >15 km.h-1) completed in the first 15 minutes of competitive football matches differed from that completed in the corresponding 15 minutes of the second half. Twenty semi-professional soccer players (age 21.2 ± 3.6 years, body mass 76.4 ± 3.8 kg, height 1.89 ± 0.05 m) participated in the study. Fifty competitive soccer matches and 192 data files were analysed (4 ± 2 files per match) using Global Positioning Satellite technology. Data were analysed using 2-way repeated measures ANOVA and Pearson correlations. No differences were found between the first 15 min of each half for the distance completed at high-speed (>15 km.h-1) or sprinting (>21 km.h-1), or in the number of sprints undertaken (p>0.05). However, total distance covered was shorter (1st half vs. 2nd half: 1746 ± 220 vs. 1644 ± 224 m; p<0.001) and mean speed lower (1st half vs. 2nd half: 7.0 ± 0.9 vs. 6.6 ± 0.9 km.h-1; p<0.001) in the first 15 min of the second half compared to the first. The correlations between the duration of the half-time interval and the difference in the high-speed running or sprinting between first and second halves (0-15 min) were very small (r=0.08 [p=0.25] and r=0.04 [p=0.61] respectively). Therefore, this study did not find any difference between the amount of high-speed running and sprinting completed by semi-professional soccer players when the first 15 minutes of the first and second half of competitive matches were compared The maintenance of high-speed running and sprinting, as total distance and mean speed declined, may be a function of the pacing strategies adopted by players in competitive matches
Fast Computation of Smith Forms of Sparse Matrices Over Local Rings
We present algorithms to compute the Smith Normal Form of matrices over two
families of local rings.
The algorithms use the \emph{black-box} model which is suitable for sparse
and structured matrices. The algorithms depend on a number of tools, such as
matrix rank computation over finite fields, for which the best-known time- and
memory-efficient algorithms are probabilistic.
For an \nxn matrix over the ring \Fzfe, where is a power of an
irreducible polynomial f \in \Fz of degree , our algorithm requires
\bigO(\eta de^2n) operations in \F, where our black-box is assumed to
require \bigO(\eta) operations in \F to compute a matrix-vector product by
a vector over \Fzfe (and is assumed greater than \Pden). The
algorithm only requires additional storage for \bigO(\Pden) elements of \F.
In particular, if \eta=\softO(\Pden), then our algorithm requires only
\softO(n^2d^2e^3) operations in \F, which is an improvement on known dense
methods for small and .
For the ring \ZZ/p^e\ZZ, where is a prime, we give an algorithm which
is time- and memory-efficient when the number of nontrivial invariant factors
is small. We describe a method for dimension reduction while preserving the
invariant factors. The time complexity is essentially linear in where is the number of operations in \ZZ/p\ZZ to evaluate the
black-box (assumed greater than ) and is the total number of non-zero
invariant factors.
To avoid the practical cost of conditioning, we give a Monte Carlo
certificate, which at low cost, provides either a high probability of success
or a proof of failure. The quest for a time- and memory-efficient solution
without restrictions on the number of nontrivial invariant factors remains
open. We offer a conjecture which may contribute toward that end.Comment: Preliminary version to appear at ISSAC 201
The importance of real-world experience in student learning
A core module for the computer science and computing degree courses at the University of North London provided a vehicle for developing an innovative approach in teaching and learning. It served as a means of bridging the gap between real-world business information systems (BIS) development practice and that which is normally simulated in academia. We also show how students can be encouraged to be proactive in creating their own real-world learning experience within an academic environment
Recommended from our members
Effects of buffering agents on high-intensity exercise performance and capacity
High-intensity exercise results in hydrogen ion accumulation, which can have a deleterious effect on muscle function, and thus exercise tolerance. Buffering agents are commonly used to enhance exercise performance and capacity. Two such agents, β-alanine and sodium bicarbonate, increase intracellular and extracellular buffering capacity, which could contribute to an improved performance and capacity during exercise limited by increasing acidosis. Despite this, studies on the ergogenic effects of β-alanine are still in their infancy, and research on sodium bicarbonate remains equivocal. The aim of this thesis was to investigate the separate and combined effects of β-alanine and sodium bicarbonate on high-intensity exercise performance and capacity using various exercise modalities. The CCT110%, a cycling capacity test, was shown to be reliable (Chapter 4A), and subsequently employed to investigate the effect of sodium bicarbonate (Chapter 4B), β-alanine and co-supplementation of the two (Chapter 4C). Sodium bicarbonate supplementation was shown to improve total work done during the CCT110% (+4.8%), only when those experiencing gastrointestinal discomfort were removed from analyses, as was β-alanine (+14.6%); co-supplementation of the two did not confer any further benefits above β-alanine alone. Neither sodium bicarbonate (Chapter 5A) nor β-alanine or co-supplementation of the two (Chapter 5B) improved 5 x 6 s repeated running sprints (all P > 0.05)
An Improved program for the education of slow learning children in the Negro schools of Kansas City, Kansas
Excerpt: The ultimate aim of education in our democracy is to educate all children of all people, regardless of their intellectual level, to develop their fullest capabilities. To achieve this goal free public school facilities must be provided for every individual child in accordance with his needs. It is the duty of the public schools to make happy and useful citizens of all boys and girls. [...] The problem is how to develop an improved program for the education of children of low intelligence in the Negro schools. The problem raises the following related questions: (1) How can the slow learning child be determined? (2) What type of curriculum will best fit his needs? (3) How can a special curriculum be made acceptable to the child and his parents? (4) How can his training help to prepare him for industrial independence? (5) How can the child be taught the satisfaction of success? [...] This problem will include children between the ages of ten and fourteen years with intelligence quotients ranging from 50-70 and who are mental deviates out of approximately nine hundred children of fourth, fifth, and sixth grade levels in three Negro schools in Kansas City, Kansas
Valuation and International Regulation of Forest Ecosystems: Propects for a Global Forest Agreement
Deforestation poses severe environmental problems for temperate and tropical regions world-wide. An international forest agreement is necessary to protect these forests. Previous international environmental agreements provide, at best, limited protection for endangered natural resources. To conserve the world\u27s forests, an effective forest agreement must recognize the economic value of forest ecosystems. This forest agreement should define a twofold rule of responsibility: that states have a duty to protect forests located within their borders, and that other states that benefit from forests have a legal obligation to share in conservation costs
Algebraic grid generation using tensor product B-splines
Finite difference methods are more successful if the accompanying grid has lines which are smooth and nearly orthogonal. The development of an algorithm which produces such a grid when given the boundary description. Topological considerations in structuring the grid generation mapping are discussed. The concept of the degree of a mapping and how it can be used to determine what requirements are necessary if a mapping is to produce a suitable grid is examined. The grid generation algorithm uses a mapping composed of bicubic B-splines. Boundary coefficients are chosen so that the splines produce Schoenberg's variation diminishing spline approximation to the boundary. Interior coefficients are initially chosen to give a variation diminishing approximation to the transfinite bilinear interpolant of the function mapping the boundary of the unit square onto the boundary grid. The practicality of optimizing the grid by minimizing a functional involving the Jacobian of the grid generation mapping at each interior grid point and the dot product of vectors tangent to the grid lines is investigated. Grids generated by using the algorithm are presented
- …