4,233 research outputs found
Mapping Lyman Continuum escape in Tololo 1247-232
Low redshift, spatially resolved Lyman continuum (LyC) emitters allow us to
clarify the processes for LyC escape from these starburst galaxies. We use
Hubble Space Telescope (HST) WFC3 and ACS imaging of the confirmed low-redshift
LyC emitter Tol 1247-232 to study the ionization structure of the gas and its
relation to the ionizing star clusters. We perform ionization parameter mapping
(IPM) using [O III]4959, 5007 and [O II]3727 imaging as the high- and
low-ionization tracers, revealing broad, large-scale, optically thin regions
originating from the center, and reaching the outskirts of the galaxy,
consistent with LyC escape. We carry out stellar population synthesis modeling
of the 26 brightest clusters using our HST photometry. Combining these data
with the nebular photometry, we find a global LyC escape fraction of f_esc =
0.12, with uncertainties also consistent with zero escape and with all measured
f_esc values for this galaxy. Our analysis suggests that, similar to other
candidate LyC emitters, a two-stage starburst has taken place in this galaxy,
with a 12 Myr old, massive, central cluster likely having pre-cleared regions
in and around the center, and the second generation of 2 - 4 Myr old clusters
dominating the current ionization, including some escape from the galaxy.Comment: Accepted for publication in Ap
Evidence Based Practice in Juvenile Justice: Nebraska White Paper
This White Paper is the product of the collaborative effort of the University of Nebraska/Lincoln (UNL) Law and Psychology Program, the University of Nebraska/Omaha (UNO) Consortium for Crime and Justice Research and the UNO Juvenile Justice Institute. The purpose of this paper is to provide an overview for understanding, testing, and developing Evidence Based Practice (EBP) interventions that make rehabilitative services available to children in the juvenile justice system. The paper begins with a summary of a proposal for a classification system of EBP programs in the Juvenile Justice System in Nebraska and then goes on to explain the logic of the classification system.
Evidence-Based Practice in Juvenile Justice: Nebraska White Paper
This White Paper is the product of the collaborative effort of the University of Nebraska/Lincoln (UNL) Law and Psychology Program, the University of Nebraska/Omaha (UNO) Consortium for Crime and Justice Research and the UNO Juvenile Justice Institute. The purpose of this paper is to provide an overview for understanding, testing, and developing Evidence Based Practice (EBP) interventions that make rehabilitative services available to children in the juvenile justice system. The paper begins with a summary of a proposal for a classification system of EBP programs in the Juvenile Justice System in Nebraska and then goes on to explain the logic of the classification system
A compilation, tabulation and analysis of spelling errors made by pupils in grades four, five, and six in free writing of sentences using given stimuli words
Thesis (M.A.)--Boston Universit
Genome engineering of isogenic human ES cells to model autism disorders.
Isogenic pluripotent stem cells are critical tools for studying human neurological diseases by allowing one to study the effects of a mutation in a fixed genetic background. Of particular interest are the spectrum of autism disorders, some of which are monogenic such as Timothy syndrome (TS); others are multigenic such as the microdeletion and microduplication syndromes of the 16p11.2 chromosomal locus. Here, we report engineered human embryonic stem cell (hESC) lines for modeling these two disorders using locus-specific endonucleases to increase the efficiency of homology-directed repair (HDR). We developed a system to: (1) computationally identify unique transcription activator-like effector nuclease (TALEN) binding sites in the genome using a new software program, TALENSeek, (2) assemble the TALEN genes by combining golden gate cloning with modified constructs from the FLASH protocol, and (3) test the TALEN pairs in an amplification-based HDR assay that is more sensitive than the typical non-homologous end joining assay. We applied these methods to identify, construct, and test TALENs that were used with HDR donors in hESCs to generate an isogenic TS cell line in a scarless manner and to model the 16p11.2 copy number disorder without modifying genomic loci with high sequence similarity
DNA methylation in adults and during development of the self-fertilizing mangrove rivulus, Kryptolebias marmoratus
In addition to genetic variation, epigenetic mechanisms such as DNA methylation might make important contributions to heritable phenotypic diversity in populations. However, it is often difficult to disentangle the contributions of genetic and epigenetic variation to phenotypic diversity. Here, we investigated global DNA methylation and mRNA expression of the methylation-associated enzymes during embryonic development and in adult tissues of one natural isogenic lineage of mangrove rivulus fish, Kryptolebias marmoratus. Being the best-known self-fertilizing hermaphroditic vertebrate affords the opportunity to work with genetically identical individuals to examine, explicitly, the phenotypic effects of epigenetic variance. Using the LUminometric Methylation Assay (LUMA), we described variable global DNA methylation at CpG sites in adult tissues, which differed significantly between hermaphrodite ovotestes and male testes (79.6% and 87.2%, respectively). After fertilization, an immediate decrease in DNA methylation occurred to 15.8% in gastrula followed by re-establishment to 70.0% by stage 26 (liver formation). Compared to zebrafish, at the same embryonic stages, this reprogramming event seems later, deeper, and longer. Furthermore, genes putatively encoding DNA methyltransferases (DNMTs), Ten-Eleven Translocation (TET), and MeCP2 proteins showed specific regulation in adult gonad and brain, and also during early embryogenesis. Their conserved domains and expression profiles suggest that these proteins play important roles during reproduction and development. This study raises questions about mangrove rivulus' peculiar reprogramming period in terms of epigenetic transmission and physiological adaptation of individuals to highly variable environments. In accordance with the general-purpose genotype model, epigenetic mechanisms might allow for the expression of diverse phenotypes among genetically identical individuals. Such phenotypes might help to overcome environmental challenges, making the mangrove rivulus a valuable vertebrate model for ecological epigenetic studies. The mangrove rivulus, Kryptolebias marmoratus, is the best-known self-fertilizing hermaphroditic vertebrate that allows to work with genetically identical individuals to examine, explicitly, the phenotypic effects of epigenetic variance. The reprogramming event is later, more dramatic and longer than in other described vertebrates. High evolutionary conservation and expression patterns of DNMT, TET, and MeCP2 proteins in K. marmoratus suggest biological roles for each member in gametogenesis and development
External validation of a simple clinical tool used to predict falls in people with Parkinson disease
Published in final edited form as:
Parkinsonism Relat Disord. 2015 August ; 21(8): 960–963. doi:10.1016/j.parkreldis.2015.05.008.BACKGROUND: Assessment of fall risk in an individual with Parkinson disease (PD) is a critical yet often time consuming component of patient care. Recently a simple clinical prediction tool based only on fall history in the previous year, freezing of gait in the past month, and gait velocity <1.1 m/s was developed and accurately predicted future falls in a sample of individuals with PD. METHODS: We sought to externally validate the utility of the tool by administering it to a different cohort of 171 individuals with PD. Falls were monitored prospectively for 6 months following predictor assessment. RESULTS: The tool accurately discriminated future fallers from non-fallers (area under the curve [AUC] = 0.83; 95% CI 0.76–0.89), comparable to the developmental study. CONCLUSION: The results validated the utility of the tool for allowing clinicians to quickly and accurately identify an individual's risk of an impending fall.Davis Phinney Foundation, Parkinson Disease Foundation, NIH, APDA. (Davis Phinney Foundation; Parkinson Disease Foundation; NIH; APDA
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