2,804 research outputs found
Supporting the Needs of At-Risk Beginning Teachers
This session is designed to provide teachers, teacher leaders, principals, and support staff relevant research and best practices for incorporating induction support to novice teachers who have been placed in low-performing schools. This interactive session will include participant discussion on the characteristics of beginning teachers, and how mentoring and coaching can significantly impact their retention and effectiveness
Assault on Eden: Destruction of Latin America\u27s Rain Forests
In the seemingly distant world of Latin America\u27s rain forests, man\u27s greed and desperation have resulted in a fire which threatens to obscure our ability to observe life\u27s poetry: The continuing destruction of the earth\u27s tropical rain forests is one of the most serious environmental problems confronting humanity today: Intact, these vital organisms offer an understanding of the planet\u27s past and a key to our future; destroyed, they threaten catastrophe of global consequence
Self-selected walking speeds as a function of load in reproductive age women carrying an indigenous pack basket.
Keywords: Women, locomotion, loads
Almost universally, females from indigenous populations walk long distances carrying heavy loads; these loads include infants and toddlers, food, water, firewood, and household belongings. The purpose of our research was to determine how different levels of load carried in an indigenous pack basket affect the speeds selected by free-walking reproductive age women given qualitative speed directives. The study involved 14 women between 18 and 30 y who were in the luteal phase of their menstrual cycle or taking oral contraceptives. Subjects carried three different load amounts in an indigenous style pack basket -- 0 kg (an empty pack), 10 kg, and 20 kg -- while walking around a gym perimeter at four different walking speed directives (“slow walk”, “walk all day”, “brisk walk”, “fast walk”). During each of two testing days, 12 trials (all combinations of 3 loads, 4 speed directives) were performed in a random order. Each trial consisted of six minutes walking followed by four minutes resting. Average selected walking speed for each trial was determined from video tape recordings on each side of the gym. Actual walking speed increased curvilinearly with speed directive. For a given speed directive, selected speeds dropped significantly from 0 to 20 kg loads at all but the “slow walk” directive, with the amount of the speed drop increasing at faster speed directives. Such load-related modulation of walking speed could limit daily foraging range, as well as increase the frequency of camp moves, potentially influencing the mobility of the entire population
The mapping class group and the Meyer function for plane curves
For each d>=2, the mapping class group for plane curves of degree d will be
defined and it is proved that there exists uniquely the Meyer function on this
group. In the case of d=4, using our Meyer function, we can define the local
signature for 4-dimensional fiber spaces whose general fibers are
non-hyperelliptic compact Riemann surfaces of genus 3. Some computations of our
local signature will be given.Comment: 24 pages, typo adde
Improved Algorithms for Approximate String Matching (Extended Abstract)
The problem of approximate string matching is important in many different
areas such as computational biology, text processing and pattern recognition. A
great effort has been made to design efficient algorithms addressing several
variants of the problem, including comparison of two strings, approximate
pattern identification in a string or calculation of the longest common
subsequence that two strings share.
We designed an output sensitive algorithm solving the edit distance problem
between two strings of lengths n and m respectively in time
O((s-|n-m|)min(m,n,s)+m+n) and linear space, where s is the edit distance
between the two strings. This worst-case time bound sets the quadratic factor
of the algorithm independent of the longest string length and improves existing
theoretical bounds for this problem. The implementation of our algorithm excels
also in practice, especially in cases where the two strings compared differ
significantly in length. Source code of our algorithm is available at
http://www.cs.miami.edu/\~dimitris/edit_distanceComment: 10 page
Middle School Single-Gender Science Classes: Self-Concept and Discourse Analysis
One southwestern, suburban middle school in the United States implemented a voluntary, single-gender science program. Although other studies have documented the effects of single-gender instruction and recent educational innovations have focused on its benefits, minimal current research has investigated the effects in middle school science classroom contexts. This study indicated that the patterns of discourse differed between single-gender and mixed-gender classes, with single-gender male classes participating in higher levels of discourse than females in middle school single-gender classes. Overall, the self-concept for females was low in science and school performance. The discourse analysis revealed that males and females used higher level utterances when placed in single-gender classrooms
Prevalence and correlates of atypical patterns of drug use progression: findings from the South African Stress and Health Study
Objective: Atypical sequences of drug use progression are thought to have important implications for the development of substance dependence. The extent to which this assumption holds for South African populations is unknown. This paper attempts to address this gap by examining the prevalence and correlates of atypical patterns of drug progression among South Africans. Method: Data on substance use and other mental health disorders from a nationally representative sample of 4351 South Africans were analysed. Weighted cross tabulations were used to estimate prevalence and correlates of atypical patterns of drug use progression. Results: Overall, 12.2% of the sample reported atypical patterns of drug use progression. The most common violation was the use of extra-medical drugs prior to alcohol and tobacco. Gender was significantly associated with atypical patterns of drug use with the risk pattern varying by the type of drug. None of the anxiety or mood disorders were associated with atypical patterns of use. Atypical patterns of drug use were not associated with increased risk for a lifetime substance use disorder. Conclusion: Atypical patterns of drug use initiation seem more prevalent in South Africa compared to other countries. The early use of extra-medical drugs is common, especially among young women. Drug availability and social environmental factors may influence patterns of drug use. The findings have important implications for prevention initiatives and future research.Key words: Substance use; Gateway violations; Mental disorders; South Afric
Meraculous: De Novo Genome Assembly with Short Paired-End Reads
We describe a new algorithm, meraculous, for whole genome assembly of deep paired-end short reads, and apply it to the assembly of a dataset of paired 75-bp Illumina reads derived from the 15.4 megabase genome of the haploid yeast Pichia stipitis. More than 95% of the genome is recovered, with no errors; half the assembled sequence is in contigs longer than 101 kilobases and in scaffolds longer than 269 kilobases. Incorporating fosmid ends recovers entire chromosomes. Meraculous relies on an efficient and conservative traversal of the subgraph of the k-mer (deBruijn) graph of oligonucleotides with unique high quality extensions in the dataset, avoiding an explicit error correction step as used in other short-read assemblers. A novel memory-efficient hashing scheme is introduced. The resulting contigs are ordered and oriented using paired reads separated by ∼280 bp or ∼3.2 kbp, and many gaps between contigs can be closed using paired-end placements. Practical issues with the dataset are described, and prospects for assembling larger genomes are discussed
Soil organic matter and litter chemistry response to experimental N deposition in northern temperate deciduous forest ecosystems
The effects of atmospheric nitrogen (N) deposition on organic matter decomposition vary with the biochemical characteristics of plant litter. At the ecosystem-scale, net effects are difficult to predict because various soil organic matter (SOM) fractions may respond differentially. We investigated the relationship between SOM chemistry and microbial activity in three northern deciduous forest ecosystems that have been subjected to experimental N addition for 2 years. Extractable dissolved organic carbon (DOC), DOC aromaticity, C : N ratio, and functional group distribution, measured by Fourier transform infrared spectra (FTIR), were analyzed for litter and SOM. The largest biochemical changes were found in the sugar maple–basswood (SMBW) and black oak–white oak (BOWO) ecosystems. SMBW litter from the N addition treatment had less aromaticity, higher C : N ratios, and lower saturated carbon, lower carbonyl carbon, and higher carboxylates than controls; BOWO litter showed opposite trends, except for carbonyl and carboxylate contents. Litter from the sugar maple–red oak (SMRO) ecosystem had a lower C : N ratio, but no change in DOC aromaticity. For SOM, the C : N ratio increased with N addition in SMBW and SMRO ecosystems, but decreased in BOWO; N addition did not affect the aromaticity of DOC extracted from mineral soil. All ecosystems showed increases in extractable DOC from both litter and soil in response to N treatment. The biochemical changes are consistent with the divergent microbial responses observed in these systems. Extracellular oxidative enzyme activity has declined in the BOWO and SMRO ecosystems while activity in the SMBW ecosystem, particularly in the litter horizon, has increased. In all systems, enzyme activities associated with the hydrolysis and oxidation of polysaccharides have increased. At the ecosystem scale, the biochemical characteristics of the dominant litter appear to modulate the effects of N deposition on organic matter dynamics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72320/1/j.1365-2486.2005.01001.x.pd
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