1,325 research outputs found
Brightest Cluster Galaxy Alignments in Merging Clusters
The orientations of brightest cluster galaxies (BCGs) and their host clusters
tend to be aligned, but the mechanism driving this is not clear. To probe the
role of cluster mergers in this process, we quantify alignments of 38 BCGs in
22 clusters undergoing major mergers (up to Gyr after first
pericenter). We find alignments entirely consistent with those of clusters in
general. This suggests that alignments are robust against major cluster
mergers. If, conversely, major cluster mergers actually help orient the BCG,
such a process is acting quickly because the orientation is in place within
Gyr after first pericenter.Comment: accepted to Ap
Toward a transformed system to address child abuse and family violence in New Zealand
Executive Summary
Introduction The Glenn Inquiry (TGI) has contracted Institute of Environmental Science and Research Limited (ESR) to bring together the relevant experience and expertise to collaboratively model a transformed system to address child abuse and neglect (CAN) and family violence (FV) in New Zealand.
Our approach
We have treated the task of reducing FV and CAN as a ‘wicked problem’1; that is, reducing FV and CAN is a problem that cannot be solved once and for all, and is not a matter of simply applying expert knowledge. The methods used in this project have been chosen because they are appropriate for working with wicked problems: stakeholder engagement, systems thinking and inter-disciplinary analysis.
In this report, we refer to both CAN and FV. We recognise that, for some purposes, dealing with CAN requires particular strategies and treatment; however, the purpose of this report is to develop a transformed system that will reduce both CAN and other forms of FV. While the underlying causes of CAN and other FV may be considered independently, and some responses to each form of abuse will need to be particular, this report proposes a wider system of responses that will enable targeted interventions for each form of abuse.
We use the term ‘family violence’ in this report in the sense it has come to be understood in Aotearoa, and is used in Te Rito: New Zealand Family Violence Prevention Strategy. In this use, FV includes intimate partner violence, child abuse and neglect, elder abuse, inter-sibling abuse and parental abuse.
The project consisted of four work-streams:
A review of the international and national literature on what would constitute a high performing system to address CAN and FV, including a review of New Zealand’s current approach with a focus on government legalisation, policies and initiatives;
Qualitative modelling of the system dynamics associated with the existing way in which New Zealand has responded to CAN and FV;
A secondary (sociological) analysis of suggestions for system improvement from the People’s Report; and,
Developing a systemic model of a transformed system through collaborative workshops with sector experts
Comparing Kirchhoff-approximation and boundary-element models for computing gadoid target strengths
To establish the validity of the boundary-element method (BEM) for modeling scattering by swimbladder-bearing fish, the BEM is exercised in several ways. In a computation of backscattering by a 50-mm-diam spherical void in sea water at the four frequencies 38.1, 49.6, 68.4, and 120.4 kHz, agreement with the analytical solution is excellent. In computations of target strength as a function of tilt angle for each of 15 surface-adapted gadoids for which the swimbladders were earlier mapped, BEM results are in close agreement with Kirchhoff-approximation-model results at each of the same four frequencies. When averaged with respect to various tilt angle distributions and combined by regression analysis, the two models yield similar results. Comparisons with corresponding values derived from measured target strength functions of the same 15 gadoid specimens are fair, especially for the tilt angle distribution with the greatest standard deviation, namely 16°
edge2vec: Representation learning using edge semantics for biomedical knowledge discovery
Representation learning provides new and powerful graph analytical approaches
and tools for the highly valued data science challenge of mining knowledge
graphs. Since previous graph analytical methods have mostly focused on
homogeneous graphs, an important current challenge is extending this
methodology for richly heterogeneous graphs and knowledge domains. The
biomedical sciences are such a domain, reflecting the complexity of biology,
with entities such as genes, proteins, drugs, diseases, and phenotypes, and
relationships such as gene co-expression, biochemical regulation, and
biomolecular inhibition or activation. Therefore, the semantics of edges and
nodes are critical for representation learning and knowledge discovery in real
world biomedical problems. In this paper, we propose the edge2vec model, which
represents graphs considering edge semantics. An edge-type transition matrix is
trained by an Expectation-Maximization approach, and a stochastic gradient
descent model is employed to learn node embedding on a heterogeneous graph via
the trained transition matrix. edge2vec is validated on three biomedical domain
tasks: biomedical entity classification, compound-gene bioactivity prediction,
and biomedical information retrieval. Results show that by considering
edge-types into node embedding learning in heterogeneous graphs,
\textbf{edge2vec}\ significantly outperforms state-of-the-art models on all
three tasks. We propose this method for its added value relative to existing
graph analytical methodology, and in the real world context of biomedical
knowledge discovery applicability.Comment: 10 page
Population dynamics of introduced rodents in Hawai'i Volcanoes National Park 1986-1990
Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.We determined seasonal and geographical distribution patterns for four species of introduced rodents in Hawai‘i Volcanoes National Park from 1986-1990. We surveyed black rats (Rattus rattus), Polynesian rats (R. exulans), Norway rats (R. norvegicus) and house mice (Mus musculus) along an elevation gradient ranging from 90–1,820 m above sea level in five different sites using baited snap traps. Rodent community structure differed by elevation: there were more mice at montane sites and more Polynesian rats in the lowlands. We found that breeding occurred throughout the year for all species at all sites but that seasonal peaks in reproductive activity were common. Reproduction tended to be more common in the summer months at higher elevation sites and in the winter months at lower elevations. Rodents of all species were more abundant in our study in the winter than in the summer, but the differences were not significant. The overall sex ratio did not vary from a 1:1 ratio, but seasonally there were differences in sex ratio which varied with species and site. We calculated the minimum distance traveled from an assessment line and found that larger-bodied species traveled longer average distances. Pelage color in black rats was darkest in wet forest which may have adaptive value. Black and Polynesian rats were widespread in almost all habitat types, whereas mice were limited to dry and mesic sites; Norway rats were the rarest component of our sampling and found only in wet montane forest (‘Ōla‘a Forest).This analysis of historical data was made possible in part thanks to support from the National Park Service Inventory and Monitoring Program and the U.S. Geological Survey Invasive Species Program. The authors would like to acknowledge additional support from the Pacific Cooperative Studies Unit, University of Hawai‘i at Mānoa. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government
Biological Inventory of Anchialine Pool Invertebrates at Pu‘uhonua o Hōnaunau National Historical Park and Pu‘ukoholā Heiau National Historic Site, Hawai‘i Island
Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Inventories for major groups of invertebrates were completed at anchialine pool complexes in Pu‘uhonua o Hōnaunau National Historical Park (PUHO) and Pu‘ukoholā Heiau National Historic Site (PUHE) on the island of Hawai‘i. Nine pools within two pool complexes were surveyed at PUHO, along with one extensive pool at the terminus of Makeāhua Gulch at PUHE. At both parks, inventories documented previously unreported diversity, with pool complexes at PUHO exhibiting greater species richness for most taxa than the pool at PUHE. Inventories at PUHO recorded five species of molluscs, four species of crustaceans (including the candidate endangered shrimp Metabetaeus lohena), two species of Orthoptera, four species of Odonata (including the candidate endangered damselfly Megalagrion xanthomelas), fourteen species of Diptera, nine taxa of plankton, and thirteen species of ants; inventories at the PUHE pool produced only one species of mollusc, two species of crustacean, at least one species of Orthoptera, four species of Odonata, thirty species of Diptera, five taxa of plankton, and four species of ants. Further survey work may be necessary to document the full diversity of pool fauna, especially in species-rich groups like the Diptera. Inventory data will be used to generate a network wide database of species presence and distribution, and will aid in developing management plans for anchialine pool resources.This inventory was made possible thanks to support from the National Park Service
Inventory and Monitoring Program and the U.S. Geological Survey Pacific Island
Ecosystems Research Center
BK Lyncis: The Oldest Old Nova?... And a Bellwether for Cataclysmic-Variable Evolution
We summarize the results of a 20-year campaign to study the light curves of
BK Lyncis, a nova-like star strangely located below the 2-3 hour orbital period
gap in the family of cataclysmic variables. Two apparent "superhumps" dominate
the nightly light curves - with periods 4.6% longer, and 3.0% shorter, than
P_orb. The first appears to be associated with the star's brighter states
(V~14), while the second appears to be present throughout and becomes very
dominant in the low state (V~15.7).
Starting in the year 2005, the star's light curve became indistinguishable
from that of a dwarf nova - in particular, that of the ER UMa subclass.
Reviewing all the star's oddities, we speculate: (a) BK Lyn is the remnant of
the probable nova on 30 December 101, and (b) it has been fading ever since,
but has taken ~2000 years for the accretion rate to drop sufficiently to permit
dwarf-nova eruptions. If such behavior is common, it can explain other puzzles
of CV evolution. One: why the ER UMa class even exists (because all members can
be remnants of recent novae). Two: why ER UMa stars and short-period novalikes
are rare (because their lifetimes, which are essentially cooling times, are
short). Three: why short-period novae all decline to luminosity states far
above their true quiescence (because they're just getting started in their
postnova cooling). Four: why the orbital periods, accretion rates, and
white-dwarf temperatures of short-period CVs are somewhat too large to arise
purely from the effects of gravitational radiation (because the unexpectedly
long interval of enhanced postnova brightness boosts the mean mass-transfer
rate). These are substantial rewards in return for one investment of
hypothesis: that the second parameter in CV evolution, besides P_orb, is time
since the last classical-nova eruption.Comment: PDF, 46 pages, 4 tables, 10 figures; in preparation; more info at
http://cbastro.org
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