12,943 research outputs found
Data Mining Climate Variability as an Indicator of U.S. Natural Gas
Anomalously cold winters with extreme storms strain natural gas (NG) markets due to heightened demand for heating and electricity generation. While extended weather forecasting has become an indicator for NG management, seasonal (2â3 month) prediction could mitigate the impact of extreme winters on the NG market for consumers and industry. Interrelated climate patterns of ocean and atmospheric circulation anomalies exhibit characteristics useful for developing effective seasonal outlooks of NG storage and consumption due to their influence on the persistence and intensity of extreme winter weather in North America. This study explores the connection between the Pacific-North American climate systems and the NG market in the U.S., connecting macro-scale oceanic and atmospheric processes to regional NG storage and consumption. Western Pacific sea surface temperatures and atmospheric pressure patterns describe significant variation in seasonal NG storage and consumption. Prediction of these coupled climate processes is useful for estimating NG storage and consumption; this could facilitate economic adaptation toward extreme winter weather conditions. Understanding the implicated impact of climate variability on NG is a crucial step toward economic adaptation to climate change
Climatology of the U.S. Inter-Mountain West
The Inter-Mountain West (IMW) of North America is a region that lies between the Rocky Mountains to the east and the Cascades and Sierra Nevada to the west (Fig. 1). The climate of the IMW is generally semi-arid but this varies by location and elevation. An estimated 50- 80% of the IMWâs streams and rivers are fed by mountain snowpack (Marks and Winstral 2001), while the majority of the streams and rivers flow into desert sinks or closed-basin lakes such as the Great Salt Lake (Fig. 1). These streams and rivers create some agriculturally productive areas in the otherwise dry basins and mountain valleys. In particular, the Colorado River supplies water to the population-booming southwestern states and cities. Climate in the Colorado River Basin has been a subject of intense research due to its projected drying trend (Barnett and Pierce 2008). Change in winter precipitation regime (i.e. ratio between rainfall and snowfall) is also a subject of interest not only because its role in water resource but also its impact on recreational (ski) industry in the IMW.https://digitalcommons.usu.edu/modern_climatology/1005/thumbnail.jp
Quantitative Attribution of Climate Effects on Hurricane Harveyâs Extreme Rainfall in Texas
Hurricane Harvey made landfall in August 2017 as the first land-falling category 4 hurricane to hit the state of Texas since Hurricane Carla in September 1961. While its intensity at landfall was notable, most of the vast devastation in the Houston metropolitan area was due to Harvey stalling near the southeast Texas coast over the next several days. Harvey\u27s long-duration rainfall event was reminiscent of extreme flooding that occurred in the neighboring state of Louisiana: both of which were caused by a stalled tropical low-pressure system producing four days of intense precipitation. A quantitative attribution analysis of Harvey\u27s rainfall was conducted using a mesoscale atmospheric model forced by constrained boundary and initial conditions that had their long-term climate trends removed. The removal of the various trends of the boundary and initial conditions minimizes the effects of warming in the air and the ocean surface on Harvey. The 60 member ensemble simulations suggest that post-1980 climate warming could have contributed to the extreme precipitation that fell on southeast Texas during 26â29 August 2017 by approximately 20%, with an interquartile range of 13%â37%. While the attribution outcome could be model dependent, this downscaling approach affords the closest means possible of a case-to-case comparison for event attribution, complementing other statistics-based attribution studies on Harvey. Further analysis of a global climate model tracking Harvey-like stalling systems indicates an increase in storm frequency and intensity over southeast Texas through the mid-21st century
Detecting the inseparability and distillability of continuous variable states in Fock space
The partial transposition(PT) operation is an effecient tool in detecting the
inseparability of a mixed state. We give an explicit formula for the PT
operation for the continuous variable states in Fock space. We then give the
necessary and sufficient condition for the positivity of Gaussian operators.
Based on this, a number of creterions on the inseparability and distillability
for the multimode Gaussian states are naturally drawn. We finally give an
explicit formula for the state in a subspace of a global Gaussian state. This
formula, together with the known results for Gaussian states, gives the
criterions for the inseparability and distillability in a subspace of the
global Gaussian state.Comment: 8 pages, no figure, some typing errors correcte
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Tumor necrosis factor receptor-2 signaling pathways promote survival of cancer stem-like CD133+ cells in clear cell renal carcinoma.
Clear cell renal cell carcinoma (ccRCC) contains cancer stem-like cells (CSCs) that express CD133 (ccRCC-CD133+). CSCs are rarely in cell cycle and, as nonproliferating cells, resist most chemotherapeutic agents. Previously, we reported that tumor necrosis factor receptor-2 (TNFR2) signaling promotes the cell cycle entry of ccRCC-CD133+CSCs, rendering them susceptible to cell-cycle-dependent chemotherapeutics. Here, we describe a TNFR2-activated signaling pathway in ccRCC-CD133+CSCs that is required for cell survival. Wild-type (wt)TNF or R2TNF but not R1TNF (TNF muteins that selectively bind to TNFR2 and TNFR1) induces phosphorylation of signal transducer and activator of transcription 3 (STAT3) on serine727 but not tyrosine705, resulting in pSTAT3Ser727 translocation to and colocalization with TNFR2 in mitochondria. R2TNF signaling activates a kinase cascade involving the phosphorylation of VEGFR2, PI-3K, Akt, and mTORC. Inhibition of any of the kinases or siRNA knockdown of TNFR2 or STAT3 promotes cell death associated with mitochondrial morphological changes, cytochrome c release, generation of reactive oxygen species, and TUNEL+cells expressing phosphorylated mixed lineage kinase-like (MLKL). Pretreatment with necrostatin-1 is more protective than z-VAD.fmk, suggesting that most death is necroptotic and TNFR2 signaling promotes cell survival by preventing mitochondrial-mediated necroptosis. These data suggest that a TNFR2 selective agonist may offer a potential therapeutic strategy for ccRCC
On a Cahn--Hilliard--Darcy system for tumour growth with solution dependent source terms
We study the existence of weak solutions to a mixture model for tumour growth
that consists of a Cahn--Hilliard--Darcy system coupled with an elliptic
reaction-diffusion equation. The Darcy law gives rise to an elliptic equation
for the pressure that is coupled to the convective Cahn--Hilliard equation
through convective and source terms. Both Dirichlet and Robin boundary
conditions are considered for the pressure variable, which allows for the
source terms to be dependent on the solution variables.Comment: 18 pages, changed proof from fixed point argument to Galerkin
approximatio
Mesozoic intraplate granitic magmatism in the Altai accretionary orogen, NW China: implications for the orogenic architecture and crustal growth
The Central Asian Orogenic Belt (CAOB) is the world's largest Phanerozoic accretionary orogen and is the most important site for juvenile crustal growth in the Phanerozoic. In this work, we employed U-Pb zircon geochronology to identify the early and middle Mesozoic intraplate granitic intrusive events in the Chinese Altai segment of the southern CAOB in order to better understand the crustal architecture of the CAOB. We also used whole-rock geochemical, Sr-Nd isotopic and zircon Hf isotopic data to constrain the generation for these granitic rocks and to evaluate the implications for vertical crustal growth in this region. The Early Mesozoic granitic intrusions were emplaced between 220 and 200 Ma in the central Altai âmicrocontinental terraneâ (also widely referred to as Units 2 and 3). The granites have shoshonitic and high-K calc-alkaline affinities and show the characteristics of differentiated I-type granite. The whole-rock initial 87Sr/86Sr ratios (0.7058-0.7128) and ΔNd(210) values (â0.6 to â4.3), as well as the zircon ΔHf(t) values (â4.0 to +5.0) and two-stage Hf model ages (0.94-1.52 Ga), suggest that the granitic magmas were produced from a mixed source with both mantle-derived and recycled crustal components. The middle Mesozoic granites were emplaced at ~150 Ma in the southern Altai âaccretionary terraneâ (Units 4 and 5). They show A-type characteristics with the REE tetrad effect and have positive ΔNd(151) whole-rock values of +1.0 to +5.2 and two-stage Nd model ages (TDM2) of 0.6 to 1.0 Ga. Zircon Hf data show positive zircon ΔHf(151) values of +1 to +8 and two-stage Hf model ages of 0.6 to 1.2 Ga. The Nd-Hf isotopic data suggest that the granitic magmas were derived from short-lived juvenile mantle-derived materials. Thus, the isotopic signatures of all the Mesozoic granites from the central (old terrane) and southern (young accretional terrane) Altai suggest that the basement of both terranes has retained its original nature. The data further imply that the Altai orogen has kept its original architecture of Paleozoic horizontal accretion during Mesozoic time, as commonly observed in accretionary orogens where horizontal tectonics are dominant. All the early Mesozoic intrusions in the Altai were emplaced in an intraplate anorogenic setting; hence are distinguished from the contemporaneous syn- or post-orogenic magmatism in the eastern CAOB. We conclude that the early Mesozoic granites in the CAOB were emplaced in a variety of tectonic settings
Study on Evolvement Complexity in an Artificial Stock Market
An artificial stock market is established based on multi-agent . Each agent
has a limit memory of the history of stock price, and will choose an action
according to his memory and trading strategy. The trading strategy of each
agent evolves ceaselessly as a result of self-teaching mechanism. Simulation
results exhibit that large events are frequent in the fluctuation of the stock
price generated by the present model when compared with a normal process, and
the price returns distribution is L\'{e}vy distribution in the central part
followed by an approximately exponential truncation. In addition, by defining a
variable to gauge the "evolvement complexity" of this system, we have found a
phase cross-over from simple-phase to complex-phase along with the increase of
the number of individuals, which may be a ubiquitous phenomenon in multifarious
real-life systems.Comment: 4 pages and 4 figure
Quantum Algebras Associated With Bell States
The antisymmetric solution of the braided Yang--Baxter equation called the
Bell matrix becomes interesting in quantum information theory because it can
generate all Bell states from product states. In this paper, we study the
quantum algebra through the FRT construction of the Bell matrix. In its four
dimensional representations via the coproduct of its two dimensional
representations, we find algebraic structures including a composition series
and a direct sum of its two dimensional representations to characterize this
quantum algebra. We also present the quantum algebra using the FRT construction
of Yang--Baxterization of the Bell matrix.Comment: v1: 15 pages, 2 figures, latex; v2: 18 pages, 2 figures, latex,
references and notes adde
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