10,790 research outputs found
Regulation of gene expression and its role in long-term memory and synaptic plasticity
Histories of science yet to be written will view the latter half of this century as the Age of Molecular Genetics. From a flash of insight that yielded the double helix (1) to the first genetic clone of a mammal (2), molecular genetics has invaded every aspect of biological research. Initially, this molecular-genetic onslaught was limited to species, such as bacteria, yeast, nematodes, and fruit flies, whose size and life cycle constituted an economy of scale that was advantageous to breeding (3). With the introduction of gene-knockout techniques to mice (4), however, molecular genetics now is storming mammals (5, 6). In the broadest sense, the recent paper by Guzowski and McGaugh (7) represents a vanguard of this invasion. By using antisense oligonucleotides as “pharmaceutical” disruptors of gene expression, they have liberated molecular genetics from breeding. Endogenous regulation of gene expression has been outflanked by exogenous control
Review of \u3cem\u3eHealing from the Trauma of Childhood Sexual Abuse: The Journey for Women.\u3c/em\u3e Karen A. Duncan. Reviewed by Carol T. Tully.
Book review of Karen A. Duncan, Healing from the Trauma of Childhood Sexual Abuse The Journey for Women. Westport, CT: Praegar 2004, $39.95 hardcove
Review of \u3cem\u3eThe Global Emergence of Gay and Lesbian Politics: National Imprints of a Worldwide Movement.\u3c/em\u3e Barry D. Adam, Jan Willem Duyvendak and Andre Krouwel (Eds.). Reviewed by Carol T. Tully, Tulane University.
Book review of Barry D. Adam, Jan Willem Duyvendak and Andre Krouwel (Eds.), The Global Emergence of Gay and Lesbian Politics: National Imprints of a Worldwide Movement. Philadelphia, PA: Temple University Press, 1999. 22.95 papercover
Unified Brane Gravity: Cosmological Dark Matter from Scale Dependent Newton Constant
We analyze, within the framework of unified brane gravity, the weak-field
perturbations caused by the presence of matter on a 3-brane. Although deviating
from the Randall-Sundrum approach, the masslessness of the graviton is still
preserved. In particular, the four-dimensional Newton force law is recovered,
but serendipitously, the corresponding Newton constant is shown to be
necessarily lower than the one which governs FRW cosmology. This has the
potential to puzzle out cosmological dark matter. A subsequent conjecture
concerning galactic dark matter follows.Comment: 6 pages, to be published in Phys. Rev.
Survey of Social Work Educators: Qualifications and Compliance Criteria
In its Criteria for Accreditation (1987), the College Commission of the Southern Association of Colleges and Schools (SACS) implemented faculty qualifications standards that were strictly defined. Compliance with these standards in undergraduate and graduate schools of social work was the focus of this study. Data were gathered on 137 social work programs and include faculty qualifications information on 874 social work educators teaching in private and public institutions of higher education in the southern region. The findings indicate that baccalaureate programs in social work were more likely to be in compliance with SACS criteria than graduate schools. Strict compliance rates across all programs was low
Fruit flies and intellectual disability
Mental retardation-known more commonly nowadays as intellectual disability-is a severe neurological condition affecting up to 3% of the general population. As a result of the analysis of familial cases and recent advances in clinical genetic testing, great strides have been made in our understanding of the genetic etiologies of mental retardation. Nonetheless, no treatment is currently clinically available to patients suffering from intellectual disability. Several animal models have been used in the study of memory and cognition. Established paradigms in Drosophila have recently captured cognitive defects in fly mutants for orthologs of genes involved in human intellectual disability. We review here three protocols designed to understand the molecular genetic basis of learning and memory in Drosophila and the genes identified so far with relation to mental retardation. In addition, we explore the mental retardation genes for which evidence of neuronal dysfunction other than memory has been established in Drosophila. Finally, we summarize the findings in Drosophila for mental retardation genes for which no neuronal information is yet available. All in all, this review illustrates the impressive overlap between genes identified in human mental retardation and genes involved in physiological learning and memory
The Balance of Dark and Luminous Mass in Rotating Galaxies
A fine balance between dark and baryonic mass is observed in spiral galaxies.
As the contribution of the baryons to the total rotation velocity increases,
the contribution of the dark matter decreases by a compensating amount. This
poses a fine-tuning problem for \LCDM galaxy formation models, and may point to
new physics for dark matter particles or even a modification of gravity.Comment: 4 pages RevTeX. Phys. Rev. Letters, in pres
Light Propagation in Inhomogeneous Universes. IV. Strong Lensing and Environmental Effects
We study the gravitational lensing of high-redshift sources in a LCDM
universe. We have performed a series of ray-tracing experiments, and selected a
subsample of cases of strong lensing (multiple images, arcs, and Einstein
rings). For each case, we identify a massive galaxy that is primarily
responsible for lensing, and studied how the various density inhomogeneities
along the line of sight (other galaxies, background matter) affect the
properties of the image. The matter located near the lensing galaxy, and
physically associated with it, has a small effect. The background matter
increases the magnification by a few percents at most, while nearby galaxies
can increase it by up to about 10 percent. The effect on the image separation
is even smaller. The only significant effect results from the random alignment
of physically unassociated galaxies, which can increase the magnification by
factors of several, create additional images, and turn arcs into rings. We
conclude that the effect of environment on strong lensing in negligible in
general, and might be important only in rare cases. We show that our conclusion
does not depend on the radial density profile of the galaxies responsible for
lensing.Comment: 23 pages, 7 figures (one in color). Accepted for publication in The
Astrophysical Journal. Minor typos correcte
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