1,100 research outputs found
Neurobiology: The Eye within the Brain
SummaryAll vertebrates except mammals have photoreceptors within their brains; however, the light-sensitive cells have never been unambiguously identified. A new paper provides direct evidence of photosensitivity in cerebrospinal fluid (CSF)-contacting neurons in quail brain that mediate the seasonal reproductive response
Burdening the Plaintiff: Proving Employment Discrimination after \u3ci\u3eKastanis v. Educational Employees Credit Union\u3c/i\u3e
In Kastanis v. Educational Employees Credit Union, the Washington Supreme Court held that a plaintiff who presents direct, undisputed evidence of discrimination bears the burden of persuading the jury that the employer\u27s actions were not justified by business necessity. By substantially increasing the plaintiff\u27s burden, this decision will make it more difficult for plaintiffs to successfully litigate employment discrimination claims in Washington State. Not only is the court\u27s reasoning contrary to existing state and federal law, but there are also strong policy reasons arguing against the continued application of the court\u27s rule
The Philosopher\u27s Diagnosis: Sickness in Plato, Nietzsche, Kierkegaard, and Heidegger
Senior Project submitted to The Division of Social Studies of Bard College
Effect of Transplanting Suprachiasmatic Nuclei from Donors of Different Ages into Completely SCN Lesioned Hamsters
The suprachiasmatic nucleus (SCN) is the
primary circadian pacemaker in mammals.
Ralph and colleagues/14/provided recent new
evidence for this by transplanting SCNs between
golden hamsters with different genetically
determined periods and producing circadian
rhythmsof running wheel activity with periods
characteristic of the donor. We have extended
these studies in order to evaluate the age range
of donor tissue that can be used for transplantation.
SCN of hamsters from embryonic day 11
through postnatal day 12 can serve as functional
grafts to restore rhythmicity to arrhythmic SCN
lesioned animals. The time between SCN transplantation
and onset of rhythmicity does not
depend on the age of the donor. The presence of
patches containing vasoactive intestinal peptide
(VIP) immunoreactive cells is a good indicator
of graft success, while its absence is correlated
with a lack of transplant effect. The 18 day span
during which SCN tissue can be harvested for
transplantation should expand the uses to which
this technique can be put. Our results also
suggest that it would be advantageous to
examine the age range of neural tissue that ca’n
be used in other transplantation models
Factors Determining the Restoration of Circadian Behavior by Hypothalamic Transplants
The expression of locomotor activity by
golden hamsters is temporally controlled by
circadian oscillators contained within the
suprachiasmatic nucleus (SCN). A genetic
mutation has been found that alters the
freerunning period of the locomotor activity
rhythm from the wild-type value of ~24 hours to
~20 hours in homozygous mutants. It has been
shown previously that a transplant of fetal
hypothalamic tissue containing the SCN to a
host rendered arrhythmic by a complete lesion
of the SCN restores rhythmicity with the
freerunning period which is normally expressed
by the donor genotype. To investigate the
mechanisms by which the SCN controls the
temporal organization of behavior, we made
partial lesions to the SCN of hosts of one
genotype, and then placed hypothalamic
implants from fetal donors of a different
genotype into the lesion site. By varying the size
of the host's partial SCN lesion and the duration
of time between lesioning and transplantation,
we have attempted to alter the relative amount
of host and donor control over the expression of
locomotor activity. We found that the expression
of donor rhythmicity requires the presence of a
lesion to the host SCN, and that the incidence of
donor expression increased as a function of host
SCN lesion size. Neither the duration of time
between lesioning and transplantation, nor the
location of the transplant within the third
ventricle had independent effects on the incidence of donor rhythm expression; however,
there was a strong suggestion of an effect of
their interaction
Las formas del diálogo y del monólogo en las leyendas de Gustavo Adolfo Bécquer análisis de tres leyendas elegidas
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