5,135 research outputs found
Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems
New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from
Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events
have occurred with an average repeat time of ?? 600 years since the first post-Mazama event ?? 7500 years ago. The youngest
event ?? 300 years ago probably coincides with widespread evidence of coastal subsidence and tsunami inundation in buried
marshes along the Cascadia coast. We can extend the Holocene record to at least 9850 years, during which 18 events correlate
along the same region. The pattern of repeat times is consistent with the pattern observed at most (but not all) localities
onshore, strengthening the contention that both were produced by plate-wide earthquakes. We also observe that the
sequence of Holocene events in Cascadia may contain a repeating pattern, a tantalizing look at what may be the long-term
behavior of a major fault system. Over the last ?? 7500 years, the pattern appears to have repeated at least three times, with
the most recent A.D. 1700 event being the third of three events following a long interval of 845 years between events T4
and T5. This long interval is one that is also recognized in many of the coastal records, and may serve as an anchor point
between the offshore and onshore records. Similar stratigraphic records are found in two piston cores and one box core
from Noyo Channel, adjacent to the Northern San Andreas Fault, which show a cyclic record of turbidite beds, with thirty-
one turbidite beds above a Holocene/.Pleistocene faunal «datum». Thus far, we have determined ages for 20 events
including the uppermost 5 events from these cores. The uppermost event returns a «modern» age, which we interpret is
likely the 1906 San Andreas earthquake. The penultimate event returns an intercept age of A.D. 1664 (2 ?? range 1505-
1822). The third event and fourth event are lumped together, as there is no hemipelagic sediment between them. The age
of this event is A.D. 1524 (1445-1664), though we are not certain whether this event represents one event or two. The fifth
event age is A.D. 1204 (1057-1319), and the sixth event age is A.D. 1049 (981-1188). These results are in relatively good
agreement with the onshore work to date, which indicates an age for the penultimate event in the mid-1600 s, the most likely
age for the third event of ?? 1500-1600, and a fourth event ?? 1300. We presently do not have the spatial sampling needed
to test for synchroneity of events along the Northern San Andreas, and thus cannot determine with confidence that the
observed turbidite record is earthquake generated. However, the good agreement in number of events between the onshore
and offshore records suggests that, as in Cascadia, turbidite triggers other than earthquakes appear not to have added significantly
to the turbidite record along the northernmost San Andreas margin during the last ?? 2000 years
Weed management systems for environmentally sensitive areas (2002)
"New 11/02/5M.""Integrated pest management.""Plant protection programs : College of Agriculture, Food and Natural Resources.""This publication is part of a series of IPM Manuals prepared by the Plant Protection Programs of the University of Missouri. Topics covered in the series include an introduction to scouting, weed identification and management, plant diseases, and insects of field and horticultural crops.
Large carnivore distribution, conflicts and threats in the east of the Somali region, Ethiopia
Large carnivore distribution in Ethiopia is not well documented; we did 108 interviews and 12 focus group discussions in six districts of the Somali Region to gather basic information. The Region is not listed as resident range for big cats, but our results indicate widespread presence of cheetah, and possible remnants of lion and leopard occurrence. Spotted and striped hyaena, plus many smaller species, are frequently encountered. In contrast to positive attitudes towards wild grazers, all carnivores are persecuted in response to frequent conflict leading to injuries and deaths among people and livestock. Lion and cheetah cubs were regularly captured and trafficked, and this may have contributed to lion declines especially. Cheetah cubs are still regularly caught and we mapped how they are smuggled to Somalia/Somaliland from where they enter the pet trade
A predictive model for kidney transplant graft survival using machine learning
Kidney transplantation is the best treatment for end-stage renal failure
patients. The predominant method used for kidney quality assessment is the Cox
regression-based, kidney donor risk index. A machine learning method may
provide improved prediction of transplant outcomes and help decision-making. A
popular tree-based machine learning method, random forest, was trained and
evaluated with the same data originally used to develop the risk index (70,242
observations from 1995-2005). The random forest successfully predicted an
additional 2,148 transplants than the risk index with equal type II error rates
of 10%. Predicted results were analyzed with follow-up survival outcomes up to
240 months after transplant using Kaplan-Meier analysis and confirmed that the
random forest performed significantly better than the risk index (p<0.05). The
random forest predicted significantly more successful and longer-surviving
transplants than the risk index. Random forests and other machine learning
models may improve transplant decisions.Comment: This work has been published: Pahl ES, Street WN, Johnson HJ, Reed
AI. "A Predictive Model for Kidney Transplant Graft Survival Using Machine
Learning." 4th International Conference on Computer Science and Information
Technology (COMIT 2020), November 28-29, 2020, Dubai, UAE. ISBN:
978-1-925953-30-5. Volume 10, Number 16.10.5121/csit.2020.10160
Distinction of disorder, classical and quantum vibrational contributions to atomic mean-square amplitudes in dielectric pentachloronitrobenzene
The solid-state molecular disorder of pentachloronitrobenzene (PCNB) and its
role in causing anomalous dielectric properties are investigated. Normal
coordinate analysis (NCA) of atomic mean-square displacement parameters (ADPs)
is employed to distinguish disorder contributions from classical and
quantum-mechanical vibrational contributions. The analysis relies on
multitemperature (5-295 K) single-crystal neutron-diffraction data. Vibrational
frequencies extracted from the temperature dependence of the ADPs are in good
agreement with THz spectroscopic data. Aspects of the static disorder revealed
by this work, primarily tilting and displacement of the molecules, are compared
with corresponding results from previous, much more in-depth and time-consuming
Monte Carlo simulations; their salient findings are reproduced by this work,
demonstrating that the faster NCA approach provides reliable constraints for
the interpretation of diffuse scattering. The dielectric properties of PCNB can
thus be rationalized by an interpretation of the temperature-dependent ADPs in
terms of thermal motion and molecular disorder. The use of atomic displacement
parameters in the NCA approach is nonetheless hostage to reliable neutron data.
The success of this study demonstrates that state-of-the-art single-crystal
Laue neutron diffraction affords sufficiently fast the accurate data for this
type of study. In general terms, the validation of this work opens up the field
for numerous studies of solid-state molecular disorder in organic materials.Comment: Now published in Physical Review
Gender differences in survival among adult patients starting antiretroviral therapy in South Africa: a multicentre cohort study.
Increased mortality among men on antiretroviral therapy (ART) has been documented but remains poorly understood. We examined the magnitude of and risk factors for gender differences in mortality on ART
Loss of HIF-1α in endothelial cells disrupts a hypoxia-driven VEGF autocrine loop necessary for tumorigenesis
AbstractWe deleted the hypoxia-responsive transcription factor HIF-1α in endothelial cells (EC) to determine its role during neovascularization. We found that loss of HIF-1α inhibits a number of important parameters of EC behavior during angiogenesis: these include proliferation, chemotaxis, extracellular matrix penetration, and wound healing. Most strikingly, loss of HIF-1α in EC results in a profound inhibition of blood vessel growth in solid tumors. These phenomena are all linked to a decreased level of VEGF expression and loss of autocrine response of VEGFR-2 in HIF-1α null EC. We thus show that a HIF-1α-driven, VEGF-mediated autocrine loop in EC is an essential component of solid tumor angiogenesis
Complexity Framework for Forbidden Subgraphs IV: The Steiner Forest Problem
We study Steiner Forest on -subgraph-free graphs, that is, graphs that do
not contain some fixed graph as a (not necessarily induced) subgraph. We
are motivated by a recent framework that completely characterizes the
complexity of many problems on -subgraph-free graphs. However, in contrast
to e.g. the related Steiner Tree problem, Steiner Forest falls outside this
framework. Hence, the complexity of Steiner Forest on -subgraph-free graphs
remained tantalizingly open. In this paper, we make significant progress
towards determining the complexity of Steiner Forest on -subgraph-free
graphs. Our main results are four novel polynomial-time algorithms for
different excluded graphs that are central to further understand its
complexity. Along the way, we study the complexity of Steiner Forest for graphs
with a small -deletion set, that is, a small set of vertices such that
each component of has size at most . Using this parameter, we give two
noteworthy algorithms that we later employ as subroutines. First, we prove
Steiner Forest is FPT parameterized by when (i.e. the vertex cover
number). Second, we prove Steiner Forest is polynomial-time solvable for graphs
with a 2-deletion set of size at most 2. The latter result is tight, as the
problem is NP-complete for graphs with a 3-deletion set of size 2
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