4,883 research outputs found
The fundamental plane of evolving red nuggets
We present an exploration of the mass structure of a sample of 12 strongly
lensed massive, compact early-type galaxies at redshifts to provide
further possible evidence for their inside-out growth. We obtain new ESI/Keck
spectroscopy and infer the kinematics of both lens and source galaxies, and
combine these with existing photometry to construct (a) the fundamental plane
(FP) of the source galaxies and (b) physical models for their dark and luminous
mass structure. We find their FP to be tilted towards the virial plane relative
to the local FP, and attribute this to their unusual compactness, which causes
their kinematics to be totally dominated by the stellar mass as opposed to
their dark matter; that their FP is nevertheless still inconsistent with the
virial plane implies that both the stellar and dark structure of early-type
galaxies is non-homologous. We also find the intrinsic scatter of their FP to
be comparable to the local value, indicating that variations in the stellar
mass structure outweight variations in the dark halo in the central regions of
early-type galaxies. Finally, we show that inference on the dark halo structure
-- and, in turn, the underlying physics -- is sensitive to assumptions about
the stellar initial mass function (IMF), but that physically-motivated
assumptions about the IMF imply haloes with sub-NFW inner density slopes, and
may present further evidence for the inside-out growth of compact early-type
galaxies via minor mergers and accretion.Comment: 10 pages, 3 figures, 3 tables; submitted to MNRA
Design data for brazed Rene 41 honeycomb sandwich
Strength data, creep data and residual strength data after cyclic thermal exposure were obtained at temperatures from 78 K to 1144 K (-320 F to 1600 F). The influences of face thickness, core depth, core gage, cell size and thermal/stress exposure conditions on the mechanical design properties were investigated. A braze alloy and process was developed that is adequate to fully develop the strength of the honeycomb core while simultaneously solution treating and aging the Rene 41 fact sheets. New test procedures and test specimen configurations were developed to avoid excessive thermal stresses during cyclic thermal exposure
How effective are risk assessments/measures for predicting future aggressive behaviour in adults with intellectual disabilities (ID): A systematic review and meta-analysis
Background:
Risk assessments assist professionals in the identification and management of risk of aggression. The present study aimed to systematically review evidence on the efficacy of assessments for managing the risk of physical aggression in adults with intellectual disabilities (ID).
Methods:
A literature search was conducted using the databases PsycINFO, EMBASE, MEDLINE, Web of Science, and Google Scholar. Electronic and hand searches identified 14 studies that met the inclusion criteria. Standardised mean difference effect sizes Area Under Curve (AUC) were calculated for studies. Random effects subgroup analysis was used to compare different types of risk measures (Actuarial, Structured Professional Judgment and dynamic), and prospective vs. catch-up longitudinal study designs.
Results:
Overall, evidence of predictive validity was found for risk measures with ID populations: (AUC) = 0.724, 95% CI [0.681, 0.768]. There was no variation in the performance of different types of risk measures, or different study design.
Conclusions:
Risk assessment measures predict the likelihood of aggression in ID population and are comparable to those in mainstream populations. Further meta-analysis is necessary when risk measures are more established in this population
Red nuggets grow inside-out: evidence from gravitational lensing
We present a new sample of strong gravitational lens systems where both the
foreground lenses and background sources are early-type galaxies. Using imaging
from HST/ACS and Keck/NIRC2, we model the surface brightness distributions and
show that the sources form a distinct population of massive, compact galaxies
at redshifts , lying systematically below the
size-mass relation of the global elliptical galaxy population at those
redshifts. These may therefore represent relics of high-redshift red nuggets or
their partly-evolved descendants. We exploit the magnifying effect of lensing
to investigate the structural properties, stellar masses and stellar
populations of these objects with a view to understanding their evolution. We
model these objects parametrically and find that they generally require two
S\'ersic components to properly describe their light profiles, with one more
spheroidal component alongside a more envelope-like component, which is
slightly more extended though still compact. This is consistent with the
hypothesis of the inside-out growth of these objects via minor mergers. We also
find that the sources can be characterised by red-to-blue colour gradients as a
function of radius which are stronger at low redshift -- indicative of ongoing
accretion -- but that their environments generally appear consistent with that
of the general elliptical galaxy population, contrary to recent suggestions
that these objects are predominantly associated with clusters.Comment: 21 pages; accepted for publication in MNRA
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Chitosan as a rainfastness adjuvant for agrochemicals
Chitosan has been identified as an excellent rainfastness aid for a model agrochemical. We use fluorescent labelling and microscopy to show that chitosan deposits on Vicia faba leaves are able to resist wash off by rain, both in a lab-scale test and via simulated rain. Furthermore, via the same methods it has been demonstrated that the rainfastness of azoxystrobin, a common fungicide which is fluorescently active, can be improved by formulating with chitosan. These findings via fluorescent microscopy were in agreement with a quantitative LC-MS/MS method in which the exact quantity of active ingredient on a leaf surface was determined before and after a rain wash. The potential of chitosan as a rainfastness aid is further supported by positive comparison with a commercial tank-mix standard, with almost 100% retention of the model active ingredient achieved in both cases after 1 hour of washing with 10 mm h−1 intensity rain
Acoustic Spectroscopy of the DNA in GHz range
We find a parametric resonance in the GHz range of the DNA dynamics,
generated by pumping hypersound . There are localized phonon modes caused by
the random structure of elastic modulii due to the sequence of base pairs
Young peoples’ reflections on what teachers think about family obligations that conflict with school: A focus on the non-normative roles of young caring and language brokering
In “Western” contexts school attendance is central for an ‘ideal’ childhood. However, many young people engage with home roles that conflict with school expectations. This paper explores perceptions of that process in relation two home activities - language brokering and young caring. We interviewed 46 young people and asked them to reflect on what the teacher would think when a child had to miss school to help a family member. This paper discusses the young people’s overall need to keep their out-of-school lives private from their teachers
Generativity in College Students: Comparing and Explaining the Impact of Mentoring
Preparing college students to be active contributors to the next generation is an important function of higher education. This assumption about generativity forms a cornerstone in this mixed methods study that examined generativity levels among 273 college students at a 4-year public university. MANCOVA results indicated that college students who mentor demonstrated significantly higher generativity than nonmentoring students. Interviews with 9 mentoring students revealed that, although a “seed of generativity” may have already been planted, their mentoring experience served as a “lab” for learning how to be generative. The integrated findings offer important contributions relative to leadership and social responsibility
Generativity in College Students: Comparing and Explaining the Impact of Mentoring
Preparing college students to be active contributors to the next generation is an important function of higher education. This assumption about generativity forms a cornerstone in this mixed methods study that examined generativity levels among 273 college students at a 4-year public university. MANCOVA results indicated that college students who mentor demonstrated significantly higher generativity than nonmentoring students. Interviews with 9 mentoring students revealed that, although a “seed of generativity” may have already been planted, their mentoring experience served as a “lab” for learning how to be generative. The integrated findings offer important contributions relative to leadership and social responsibility
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