1,532 research outputs found
An Intuitive Approach to Geometric Continuity for Parametric Curves and Surfaces (Extended Abstract)
The notion of geometric continuity is extended to an arbitrary order for curves and surfaces, and an intuitive development of constraints equations is presented that are necessary for it. The constraints result from a direct application of the univariate chain rule for curves, and the bivariate chain rule for surfaces. The constraints provide for the introduction of quantities known as shape parameters. The approach taken is important for several reasons: First, it generalizes geometric continuity to arbitrary order for both curves and surfaces. Second, it shows the fundamental connection between geometric continuity of curves and geometric continuity of surfaces. Third, due to the chain rule derivation, constraints of any order can be determined more easily than derivations based exclusively on geometric measures
21st Century Ergonomic Education, From Little e to Big E
Despite intense efforts, contemporary educational systems are not enabling
individuals to function optimally in modern society. The main reason is that
reformers are trying to improve systems that are not designed to take advantage
of the centuries of history of the development of today's societies. Nor do
they recognize the implications of the millions of years of history of life on
earth in which humans are the latest edition of learning organisms. The
contemporary educational paradigm of "education for all" is based on a 17th
century model of "printing minds" for passing on static knowledge. This
characterizes most of K-12 education. In contrast, 21st Century education
demands a new paradigm, which we call Ergonomic Education. This is an education
system that is designed to fit the students of any age instead of forcing the
students to fit the education system. It takes into account in a fundamental
way what students want to learn -- the concept "wanting to learn" refers to the
innate ability and desire to learn that is characteristic of humans. The
Ergonomic Education paradigm shifts to education based on coaching students as
human beings who are hungry for productive learning throughout their lives from
their very earliest days.Comment: plain latex, 13 pages, 1 tabl
The Alexander Technique and Contemporary Dance: An Interview between Marsha and Robert Barsky
The Alexander Technique, based on the writings and teachings of F. M. Alexander, is a process of learning how to move with more ease, freedom, efficiency, support and balance. The technique encourages reliable integration and coordination of the mental, physical, emotional and spiritual spheres, by awakening and refining sensory awareness. It promotes a deep understanding to the means whereby we respond to stimuli, thus fostering a harmonious relationship to Self. The essence of the Alexander Technique is movement, and as the process of learning and understanding the technique unfolds, the potential for free and unfettered movement is experienced in the entire being. Modern dancers, in particular might be drawn to the Alexander Technique since the very nature and origins of modern dance deal with the freedom of self- expression in motion. Modern dancers are adept negotiators of the body, and in their work they explore a whole range of movements and facets of moving. Through diligent exploration of finely sophisticated movement patterns, a dancer’s kinesthetic sense is, -- through Alexander work, -- sharpened, refined and developed to permit the mover to perceive and convey the subtlest movement shifts
Interaction of carbonyl cyanide m-chlorophenylhydrazone with the photosystem II acceptor side
AbstractWe show that CCCP, known as an uncoupler of photophosphorylation and an ADRY agent, inhibits FeCy photoreduction and coupled O2 evolution by isolated chloroplasts equally (150 ∼ 2μM), but is practically without effect on the O2 evolution coupled with SiMo reduction within the 0.2–10μM concentration range. CCCP has no effect on the nanosecond chlorophyll fluorescence in chloroplasts incubated at low light intensity, but decreases it at high light intensity. The electron transfer from reduced TMPD or duroquinol to methylviologen is resistant to CCCP. The efficiency of the CCCP inhibitory action on the FeCy photoreduction depends on the rate of electron flow, which is controlled by the light intensity. The data obtained show that CCCP is oxidized by the photosystem II donor side and is reduced by Qp, competing for electrons with FeCy and the cytochrome blf complex
Recommended from our members
DNA Sliding Clamps: Just the Right Twist to Load onto DNA
Two recent papers illuminate a long sought step in DNA sliding clamp loading. One paper reveals the structure of the PCNA clamp wrapped around DNA--still open from being loaded--while a second paper discovers that the clamp may assist this process by forming a right-handed helix upon opening
AS2TS system for protein structure modeling and analysis
We present a set of programs and a website designed to facilitate protein structure comparison and protein structure modeling efforts. Our protein structure analysis and comparison services use the LGA (local-global alignment) program to search for regions of local similarity and to evaluate the level of structural similarity between compared protein structures. To facilitate the homology-based protein structure modeling process, our AL2TS service translates given sequence–structure alignment data into the standard Protein Data Bank (PDB) atom records (coordinates). For a given sequence of amino acids, the AS2TS (amino acid sequence to tertiary structure) system calculates (e.g. using PSI-BLAST PDB analysis) a list of the closest proteins from the PDB, and then a set of draft 3D models is automatically created. Web services are available at
Income, personality, and subjective financial well-being: the role of gender in their genetic and environmental relationships
Citation: Zyphur, M. J., Li, W. D., Zhang, Z., Arvey, R. D., & Barsky, A. P. (2015). Income, personality, and subjective financial well-being: the role of gender in their genetic and environmental relationships. Frontiers in Psychology, 6, 16. doi:10.3389/fpsyg.2015.01493Increasing levels of financial inequality prompt questions about the relationship between income and well-being. Using a twins sample from the Survey of Midlife Development in the U. S. and controlling for personality as core self-evaluations (CSE), we found that men, but not women, had higher subjective financial well-being (SFWB) when they had higher incomes. This relationship was due to 'unshared environmental' factors rather than genes, suggesting that the effect of income on SFWB is driven by unique experiences among men. Further, for women and men, we found that CSE influenced income and SFWB, and that both genetic and environmental factors explained this relationship. Given the relatively small and male-specific relationship between income and SFWB, and the determination of both income and SFWB by personality, we propose that policy makers focus on malleable factors beyond merely income in order to increase SFWB, including financial education and building self-regulatory capacity
Bulk and Interfacial Shear Thinning of Immiscible Polymers
Nonequilibrium molecular dynamics simulations are used to study the shear
thinning behavior of immiscible symmetric polymer blends. The phase separated
polymers are subjected to a simple shear flow imposed by moving a wall parallel
to the fluid-fluid interface. The viscosity begins to shear thin at much lower
rates in the bulk than at the interface. The entire shear rate dependence of
the interfacial viscosity is consistent with a shorter effective chain length
that also describes the width of the interface. This is independent
of chain length and is a function only of the degree of immiscibility of
the two polymers. Changes in polymer conformation are studied as a function of
position and shear rate.Shear thinning correlates more closely with a decrease
in the component of the radius of gyration along the velocity gradient than
with elongation along the flow. At the interface, this contraction of chains is
independent of and consistent with the bulk behavior for chains of length
. The distribution of conformational changes along chains is also studied.
Central regions begin to stretch at a shear rate that decreases with increasing
, while shear induced changes at the ends of chains are independent of .Comment: 8 pages, 8 figure
Staphylococcus aureus nasal colonization in HIV-seropositive and HIV-seronegative drug users
Nasal colonization plays an important role in the pathogenesis of Staphylococcus aureus infections. To identify characteristics associated with colonization, we studied a cross-section of a well-described cohort of HIV-seropositive and -seronegative active and former drug users considered at risk for staphylococcal infections. Sixty percent of the 217 subjects were Hispanic, 36% were women, 25% actively used injection drugs, 23% actively used inhalational drugs, 23% received antibiotics, and 35% were HIV-seropositive. Forty-one percent of subjects had positive nasal cultures for S. aureus. The antibiotic susceptibility patterns were similar to the local hospital's outpatient isolates and no dominant strain was identified by arbitrarily primed polymerase chain reaction (AB-PCR). Variables significantly and independently associated with colonization included antibiotic use (odds ratio [OR] = 0.37; confidence interval [CI] = 0.18-0.77), active inhalational drug use within the HIV-seropositive population (OR = 2.36; CI = 1.10-5.10) and female gender (OR = 1.97; CI = 1.09-3.57). Characteristics not independently associated included injection drug use, HIV status, and CD4 count. The association with active inhalational drug use, a novel finding, may reflect alterations in the integrity of the nasal mucosa. The lack of association between HIV infection and S. aureus colonization, which is contrary to most previous studies, could be explained by our rigorous control for confounding variables or by a limited statistical power due to the sample sizes
Recommended from our members
Mutations that Cause Human Disease: A Computational/Experimental Approach
International genome sequencing projects have produced billions of nucleotides (letters) of DNA sequence data, including the complete genome sequences of 74 organisms. These genome sequences have created many new scientific opportunities, including the ability to identify sequence variations among individuals within a species. These genetic differences, which are known as single nucleotide polymorphisms (SNPs), are particularly important in understanding the genetic basis for disease susceptibility. Since the report of the complete human genome sequence, over two million human SNPs have been identified, including a large-scale comparison of an entire chromosome from twenty individuals. Of the protein coding SNPs (cSNPs), approximately half leads to a single amino acid change in the encoded protein (non-synonymous coding SNPs). Most of these changes are functionally silent, while the remainder negatively impact the protein and sometimes cause human disease. To date, over 550 SNPs have been found to cause single locus (monogenic) diseases and many others have been associated with polygenic diseases. SNPs have been linked to specific human diseases, including late-onset Parkinson disease, autism, rheumatoid arthritis and cancer. The ability to predict accurately the effects of these SNPs on protein function would represent a major advance toward understanding these diseases. To date several attempts have been made toward predicting the effects of such mutations. The most successful of these is a computational approach called ''Sorting Intolerant From Tolerant'' (SIFT). This method uses sequence conservation among many similar proteins to predict which residues in a protein are functionally important. However, this method suffers from several limitations. First, a query sequence must have a sufficient number of relatives to infer sequence conservation. Second, this method does not make use of or provide any information on protein structure, which can be used to understand how an amino acid change affects the protein. The experimental methods that provide the most detailed structural information on proteins are X-ray crystallography and NMR spectroscopy. However, these methods are labor intensive and currently cannot be carried out on a genomic scale. Nonetheless, Structural Genomics projects are being pursued by more than a dozen groups and consortia worldwide and as a result the number of experimentally determined structures is rising exponentially. Based on the expectation that protein structures will continue to be determined at an ever-increasing rate, reliable structure prediction schemes will become increasingly valuable, leading to information on protein function and disease for many different proteins. Given known genetic variability and experimentally determined protein structures, can we accurately predict the effects of single amino acid substitutions? An objective assessment of this question would involve comparing predicted and experimentally determined structures, which thus far has not been rigorously performed. The completed research leveraged existing expertise at LLNL in computational and structural biology, as well as significant computing resources, to address this question
- …