1,965 research outputs found
The Case For Sequencing The Pacific Oyster Genome
An international community of biologists presents the Pacific oyster Crassostrea gigas as a candidate for genome sequencing. This oyster has global distribution and for the past several years the highest annual production of any freshwater or marine organism (4.2 million metric tons, worth $3.5 billion US). Economic and cultural importance of oysters motivates a great deal of biologic research, which provides a compelling rationale for sequencing an oyster genome. Strong rationales for sequencing the oyster genome also come from contrasts to other genomes: membership in the Lophotrochozoa, an understudied branch of the Eukaryotes and high fecundity, with concomitantly high DNA sequence polymorphism and a population biology that is more like plants than any of the model animals whose genomes have been sequenced to date. Finally, oysters play an important, sentinel role in the estuarine and coastal marine habitats, where most humans live, environmental degradation is substantial, and oysters suffer intense fishing pressures and natural mortalities from disease and stress. Consumption of contaminated oysters can pose risks to human health from infectious diseases. The genome of the Pacific oyster, at IC = 0.89 pg or similar to 824 Mb, ranks in the bottom 12% of genome sizes for the Phylum Mollusca. The biologic and genomic resources available for the Pacific oyster are unparalleled by resources for any other bivalve mollusc or marine invertebrate. Inbred lines have been developed for experimental crosses and genetics research. Use of DNA from inbred lines is proposed as a strategy for reducing the high nucleotide polymorphism, which can interfere with shotgun sequencing approaches. We have moderately dense linkage maps and various genomic and expressed DNA libraries. The value of these existing resources for a broad range of evolutionary and environmental sciences will be greatly leveraged by having a draft genome sequence
A new Detector Testbed for future FAIR based Slowed Down Beam Setups at the Cologne FN-Tandem Accelerator Facility
Grain Dynamics in a Two-dimensional Granular Flow
We have used particle tracking methods to study the dynamics of individual
balls comprising a granular flow in a small-angle two-dimensional funnel. We
statistically analyze many ball trajectories to examine the mechanisms of shock
propagation. In particular, we study the creation of, and interactions between,
shock waves. We also investigate the role of granular temperature and draw
parallels to traffic flow dynamics.Comment: 17 pages, 24 figures. To appear in Phys.Rev.E. High res./color
figures etc. on http://www.nbi.dk/CATS/Granular/GrainDyn.htm
Clustering, Order, and Collapse in a Driven Granular Monolayer
Steady state dynamics of clustering, long range order, and inelastic collapse
are experimentally observed in vertically shaken granular monolayers. At large
vibration amplitudes, particle correlations show only short range order like
equilibrium 2D hard sphere gases. Lowering the amplitude "cools" the system,
resulting in a dramatic increase in correlations leading either to clustering
or an ordered state. Further cooling forms a collapse: a condensate of
motionless balls co-existing with a less dense gas. Measured velocity
distributions are non-Gaussian, showing nearly exponential tails.Comment: 9 pages of text in Revtex, 5 figures; references added, minor
modifications Paper accepted to Phys Rev Letters. Tentatively scheduled for
Nov. 9, 199
The Importance of Time Congruity in the Organisation.
In 1991 Kaufman, Lane, and Lindquist proposed that time congruity in terms of an individual's time preferences and the time use methods of an organisation would lead to satisfactory performance and enhancement of quality of work and general life. The research reported here presents a study which uses commensurate person and job measures of time personality in an organisational setting to assess the effects of time congruity on one aspect of work life, job-related affective well-being. Results show that time personality and time congruity were found to have direct effects on well-being and the influence of time congruity was found to be mediated through time personality, thus contributing to the person–job (P–J) fit literature which suggests that direct effects are often more important than indirect effects. The study also provides some practical examples of ways to address some of the previously cited methodological issues in P–J fit research
First identification of large electric monopole strength in well-deformed rare earth nuclei
Excited states in the well-deformed rare earth isotopes Sm and
Er were populated via ``safe'' Coulomb excitation at the Munich MLL
Tandem accelerator. Conversion electrons were registered in a cooled Si(Li)
detector in conjunction with a magnetic transport and filter system, the
Mini-Orange spectrometer. For the first excited state in Sm at
1099 keV a large value of the monopole strength for the transition to the
ground state of could be extracted. This confirms the interpretation of the lowest
excited state in Sm as the collective -vibrational
excitation of the ground state. In Er the measured large electric
monopole strength of clearly identifies the state at 1934 keV to be the
-vibrational excitation of the ground state.Comment: submitted to Physics Letters
Do divorcing couples become happier by breaking up?
Divorce is a leap in the dark. The paper investigates whether people who split up actually become happier. Using the British Household Panel Survey, we can observe an individual's level of psychological well-being in the years before and after divorce. Our results show that divorcing couples reap psychological gains from the dissolution of their marriages. Men and women benefit equally. The paper also studies the effects of bereavement, of having dependant children and of remarriage. We measure well-being by using general health questionnaire and life satisfaction scores
Steady state properties of a driven granular medium
We study a two-dimensional granular system where external driving force is
applied to each particle in the system in such a way that the system is driven
into a steady state by balancing the energy input and the dissipation due to
inelastic collision between particles. The velocities of the particles in the
steady state satisfy the Maxwellian distribution. We measure the
density-density correlation and the velocity-velocity correlation functions in
the steady state and find that they are of power-law scaling forms. The
locations of collision events are observed to be time-correlated and such a
correlation is described by another power-law form. We also find that the
dissipated energy obeys a power-law distribution. These results indicate that
the system evolves into a critical state where there are neither characteristic
spatial nor temporal scales in the correlation functions. A test particle
exhibits an anomalous diffusion which is apparently similar to the Richardson
law in a three-dimensional turbulent flow.Comment: REVTEX, submitted to Phys. Rev.
Consistency of the Regularization of Gauge Theories by High Covariant Derivatives
We show that regularization of gauge theories by higher covariant derivatives
and gauge invariant Pauli-Villars regulators is a consistent method if the
Pauli-Villars vector fields are considered in a covariant in the regulating
Pauli-Villars fields is pathological and the original Slavnov proposal in
covariant Landau gauge is not correct because of the appearance of massless
modes in the regulators which do not decouple when the ultraviolet regulator is
removed. In such a case the method does not correspond to the regularization of
a pure gauge theory but that of a gauge theory in interaction with massless
ghost fields. This explains the problems pointed out by Martin and Ruiz in
covariant Landau gauge. However, a minor modification of Slavnov method
provides a consistent regularization even for such a case. The regularization
that we introduce also solves the problem of overlapping divergences in a way
similar to geometric regularization and yields the standard values of the
and functions of the renormalization group equations.Comment: 20 pages, latex, 3 Postscript figures (expanded version
- …