126 research outputs found
The Life Stories of Individuals Who as Adults Were Identified as Experiencing the Effects of Fetal Alcohol Spectrum Disorder
The teratogenic effects of prenatal alcohol exposure (PAE) can cause irreversible physical and neurological impairments that are present at birth and can have lifelong implications (McGee & Riley, 2007). One’s capacity to interact productively and effectively with one’s surroundings can be influenced further by positive and negative life events and access to appropriate social support services (Center for Disease Control and Prevention, 2004). Fetal Alcohol Spectrum Disorder (FASD) is a term used to describe a group of diagnoses and effects related to prenatal alcohol exposure (Center for Disease Control and Prevention, 2004).
Since the effects of alcohol on a fetus were not recognized formally until the mid- twentieth century, it is likely there are generations of people who are affected by this condition but remain unidentified because they were born before the sequelae of gestational alcohol exposure were understood and well documented (Massey, 2011). Few scholarly works exist that accurately represent the subjective experience of adults who have lived with the unidentified characteristics of prenatal alcohol exposure and the social and cultural factors that influence the development of their individual identity.
A narrative-style qualitative research methodology was used to explore the identity of adults living with FASD, in particular those who learned about this during adulthood. The researcher interviewed four adults living with the effects of FASD who became aware of their FASD as adults and reviewed several published autobiographical accounts as additional data sources. Upon analysis, themes of identity emerged and parallels between the life stories of the participants and other studies that address the psycho-social effects of FASD were identified. The research results suggest implications for social work practice, bring positive attention to a disenfranchised group, identify areas of needed study and shed insight into how adults living with the effects of FASD conceptualize their identity
Die Auswirkungen verschiedener Experimentiersituationen auf Leistung, Motivation und Kompetenzerwartung der Schülerinnen und Schüler
Untersucht wurde der Einfluss unterschiedlich gestalteter Experimentiersituationen auf den Leistungserwerb von Schülerinnen und Schülern, aber auch auf ihre Motivation und Kompetenzerwartung. Das Studiensetting stellt ein 2x2-Design dar, in dem zum einen nach dem Grad der Offenheit und zum anderen nach der vorliegenden Experimentiersituation differenziert wurde. Die Variation der Offenheit wurde durch einen vorstrukturierten und einen offenen Untersuchungsauftrag realisiert. Das verwendete Material lag für die eine Gruppe in Form von realen Experimentiergeräten vor, während die andere Gruppe mit einer Computersimulation arbeitete. An der Studie nahmen Schülerinnen und Schüler der Klassenstufe 8 teil. Die Ergebnisse der ersten Pilotstudie machten deutlich, dass die offen arbeitenden Gruppen einen höheren Leistungszuwachs erzielten als die gelenkten
Die Auswirkungen verschiedener Experimentiersituationen auf Leistung, Motivation und Kompetenzerwartung der Schülerinnen und Schüler
Untersucht wurde der Einfluss unterschiedlich gestalteter Experimentiersituationen auf den Leistungserwerb von Schülerinnen und Schülern, aber auch auf ihre Motivation und Kompetenzerwartung. Das Studiensetting stellt ein 2x2-Design dar, in dem zum einen nach dem Grad der Offenheit und zum anderen nach der vorliegenden Experimentiersituation differenziert wurde. Die Variation der Offenheit wurde durch einen vorstrukturierten und einen offenen Untersuchungsauftrag realisiert. Das verwendete Material lag für die eine Gruppe in Form von realen Experimentiergeräten vor, während die andere Gruppe mit einer Computersimulation arbeitete. An der Studie nahmen Schülerinnen und Schüler der Klassenstufe 8 teil. Die Ergebnisse der ersten Pilotstudie machten deutlich, dass die offen arbeitenden Gruppen einen höheren Leistungszuwachs erzielten als die gelenkten
A Study of Interstellar Gas and Stars in the Gravitationally Lensed Galaxy `The Cosmic Eye' from Rest-Frame Ultraviolet Spectroscopy
We report the results of a study of the rest-frame UV spectrum of the Cosmic
Eye, a luminous Lyman break galaxy at z=3.07331 gravitationally lensed by a
factor of 25. The spectrum, recorded with the ESI spectrograph on the Keck II
telescope, is rich in absorption features from the gas and massive stars in
this galaxy. The interstellar absorption lines are resolved into two components
of approximately equal strength and each spanning several hundred km/s in
velocity. One component has a net blueshift of -70 km/s relative to the stars
and H II regions and presumably arises in a galaxy-scale outflow similar to
those seen in most star-forming galaxies at z = 2-3. The other is more unusual
in showing a mean redshift of +350 km/s relative to the systemic redshift;
possible interpretations include a merging clump, or material ejected by a
previous star formation episode and now falling back onto the galaxy, or more
simply a chance alignment with a foreground galaxy. In the metal absorption
lines, both components only partially cover the OB stars against which they are
being viewed. We tentatively associate the redshifted component with the strong
damped Lyman alpha line, indicative of a column density N(H I) = (3.0 +/- 0.8)
x 10(21) atoms/cm2, and propose that it provides the dust `foreground screen'
responsible for the low ratio of far-infrared to UV luminosities of the Cosmic
Eye. Compared to other well-studied examples of strongly lensed galaxies, we
find that the young stellar population of the Cosmic Eye is essentially
indistinguishable from those of the Cosmic Horseshoe and MS 1512-cB58, while
the interstellar spectra of all three galaxies are markedly different,
attesting to the real complexity of the interplay between starbursts and
ambient interstellar matter in young galaxies (abridged).Comment: 14 pages, 6 Figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Society after minor revision
A Population of Metal-Poor Galaxies with ~L* Luminosities at Intermediate Redshifts
We present new spectroscopy and metallicity estimates for a sample of 15
star-forming galaxies with redshifts in the range 0.29 - 0.42. These objects
were selected in the KPNO International Spectroscopic Survey via their strong
emission lines seen in red objective-prism spectra. Originally thought to be
intermediate-redshift Seyfert 2 galaxies, our new spectroscopy in the far red
has revealed these objects to be metal-poor star-forming galaxies. These
galaxies follow a luminosity-metallicity (L-Z) relation that parallels the one
defined by low-redshift galaxies, but is offset by a factor of more than ten to
lower abundances. The amount of chemical and/or luminosity evolution required
to place these galaxies on the local L-Z relation is extreme, suggesting that
these galaxies are in a very special stage of their evolution. They may be
late-forming massive systems, which would challenge the current paradigm of
galaxy formation. Alternatively, they may represent intense starbursts in
dwarf-dwarf mergers or a major infall episode of pristine gas into a
pre-existing galaxy. In any case, these objects represent an extreme stage of
galaxy evolution taking place at relatively low redshift.Comment: 6 pages, 3 figures; to appear in 10 April 2009 ApJ
3D-HST: A wide-field grism spectroscopic survey with the Hubble Space Telescope
We present 3D-HST, a near-infrared spectroscopic Treasury program with the
Hubble Space Telescope for studying the processes that shape galaxies in the
distant Universe. 3D-HST provides rest-frame optical spectra for a sample of
~7000 galaxies at 1<z<3.5, the epoch when 60% of all star formation took place,
the number density of quasars peaked, the first galaxies stopped forming stars,
and the structural regularity that we see in galaxies today must have emerged.
3D-HST will cover 3/4 (625 sq.arcmin) of the CANDELS survey area with two
orbits of primary WFC3/G141 grism coverage and two to four parallel orbits with
the ACS/G800L grism. In the IR these exposure times yield a continuum
signal-to-noise of ~5 per resolution element at H~23.1 and a 5sigma emission
line sensitivity of 5x10-17 erg/s/cm2 for typical objects, improving by a
factor of ~2 for compact sources in images with low sky background levels. The
WFC3/G141 spectra provide continuous wavelength coverage from 1.1-1.6 um at a
spatial resolution of ~0."13, which, combined with their depth, makes them a
unique resource for studying galaxy evolution. We present the preliminary
reduction and analysis of the grism observations, including emission line and
redshift measurements from combined fits to the extracted grism spectra and
photometry from ancillary multi-wavelength catalogs. The present analysis
yields redshift estimates with a precision of sigma(z)=0.0034(1+z), or
sigma(v)~1000 km/s. We illustrate how the generalized nature of the survey
yields near-infrared spectra of remarkable quality for many different types of
objects, including a quasar at z=4.7, quiescent galaxies at z~2, and the most
distant T-type brown dwarf star known. The CANDELS and 3D-HST surveys combined
will provide the definitive imaging and spectroscopic dataset for studies of
the 1<z<3.5 Universe until the launch of the James Webb Space Telescope.Comment: Replacement reflects version now accepted by ApJS. A preliminary data
release intended to provide a general illustration of the WFC3 grism data is
available at http://3dhst.research.yale.edu
A census of metals and baryons in stars in the local Universe
We combine stellar metallicity and stellar mass estimates for a large sample
of galaxies drawn from the SDSS DR2 spanning wide ranges in physical
properties, in order to derive an inventory of the total mass of metals and
baryons locked up in stars today. Physical parameter estimates are derived from
galaxy spectra with high S/N (>20). Coadded spectra of galaxies with similar
velocity dispersions, absolute r-band magnitudes and 4000\AA-break values are
used for those regions of parameter space where individual spectra have lower
S/N. We estimate the total density of metals and of baryons in stars and, from
these two quantities, we obtain a mass- and volume-averaged stellar metallicity
of =1.04+-0.14 Z_sun, i.e. consistent with solar. We also study how
metals are distributed in galaxies according to their mass, morphology and age,
and we then compare these distributions with the corresponding distributions of
stellar mass. We find that the bulk of metals locked up in stars in the local
Universe reside in massive, bulge-dominated galaxies, with red colours and high
4000\AA-break values corresponding to old stellar populations. Bulge-dominated
and disc-dominated galaxies contribute similar amounts to the total stellar
mass density, but have different fractional contributions to the mass density
of metals in stars, in agreement with the mass-metallicity relation.
Bulge-dominated galaxies contain roughly 40% of the total amount of metals in
stars, while disc-dominated galaxies less than 25%. Finally, at a given galaxy
stellar mass, we define two characteristic ages as the median of the
distributions of mass and metals as a function of age. These characteristic
ages decrease progressively from high-mass to low-mass galaxies, consistent
with the high formation epochs of stars in massive galaxies.Comment: replaced with accepted version, minor changes, references adde
Abscisic Acid Insensitive 4 transcription factor is an important player in the response of Arabidopsis thaliana to two-spotted spider mite (Tetranychus urticae) feeding.
Plants growing in constantly changeable environmental conditions are compelled to evolve regulatory mechanisms to cope with biotic and abiotic stresses. Effective defence to invaders is largely connected with phytohormone regulation, resulting in the production of numerous defensive proteins and specialized metabolites. In our work, we elucidated the role of the Abscisic Acid Insensitive 4 (ABI4) transcription factor in the plant response to the two-spotted spider mite (TSSM). This polyphagous mite is one of the most destructive herbivores, which sucks mesophyll cells of numerous crop and wild plants. Compared to the wild-type (Col-0) Arabidopsis thaliana plants, the abi4 mutant demonstrated increased susceptibility to TSSM, reflected as enhanced female fecundity and greater frequency of mite leaf damage after trypan blue staining. Because ABI4 is regarded as an important player in the plastid-to-nucleus retrograde signalling process, we investigated the plastid envelope membrane dynamics using stroma-associated fluorescent marker. Our results indicated a clear increase in the number of stroma-filled tubular structures deriving from the plastid membrane (stromules) in the close proximity of the site of mite leaf damage, highlighting the importance of chloroplast-derived signals in the response to TSSM feeding activity
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