3,670 research outputs found
Weather, climate, and the economy: Explaining risk perceptions of global warming, 2001-10
Abstract
Two series of national survey datasets (2001-10), supplemented with monthly temperature and precipitation data and unemployment data, are used to examine how weather and climate, economic performance, and individuals\u27 sociodemographic backgrounds and political orientations affect public perceptions of global warming. Consistent with previous studies, political orientations play a key rolein determining public perceptions of global warming. Democrats and liberals are more likely than Republicans and conservatives to see global warming as an immediate and serious problem. Sociodemographic characteristics are also shown to be significant factors, with young people, women, and racial minorities likely to show higher concern about global warming than their counterparts. Moreover, individuals with lower income and higher levels of education tend to be more concerned about global warming. Net of these factors, summer temperature trends over the past 10 years, among other weather and climate measures, are shown to have consistently positive effects on public perceptions of global warming. This suggests that individuals who have experienced increasing summer heat are most likely to perceive immediate impacts and severity of global warming. Surprisingly, macroeconomic conditions - represented by the unemployment rate at the county level - do not appear to influence public perceptions of global warming
Science, scientists, and local weather: Understanding mass perceptions of global warming
Objective: To explore the effects of long-term climate trends and short-term weather fluctuations, evaluations of scientists and science, political predispositions, religious affiliation, the information environment, and demographic attributes on individuals’ views about whether global warming exists and, if so, whether it is a result of natural cycles or human activity.
Methods: We use data from the 2009 Pew General Public Science Survey, along with data on long- and short-term patterns of temperature and precipitation in individuals’ home communities.
Results: We find that long-term trends in summer temperatures influence perceptions of global warming. Individuals who reside in communities with long-term warming of summer temperatures that are coupled with long-term cooling of spring temperatures are significantly more likely to perceive that global warming exists and is due to human activity. We also find that Americans\u27 attitudes toward scientists and science, political dispositions, evangelical religious affiliation, education, and some demographic attributes all have discernible effects on their perceptions of anthropogenic (man-made) global warming.
Conclusion: Individuals’ attitudes toward global warming are influenced by long-term temperature trends in their home communities, as well as a variety of attitudinal and demographic attributes
Type 1 2HDM as effective theory of supersymmetry
It is generally believed that the low energy effective theory of the minimal
supersymmetric standard model is the type 2 two Higgs doublet model. We will
show that the type 1 two Higgs doublet model can also as the effective of
supersymmetry in a specific case with high scale supersymmetry breaking and
gauge mediation. If the other electroweak doublet obtain the vacuum expectation
value after the electroweak symmetry breaking, the Higgs spectrum is quite
different. A remarkable feature is that the physical Higgs boson mass can 125
GeV unlike in the ordinary models with high scale supersymmetry in which the
Higgs mass is generally around 140 GeV.Comment: 11 pages, 3 figures, Published in Commun.Theor.Phy
Integrated microwave acousto-optic frequency shifter on thin-film lithium niobate
Electrically driven acousto-optic devices that provide beam deflection and
optical frequency shifting have broad applications from pulse synthesis to
heterodyne detection. Commercially available acousto-optic modulators are based
on bulk materials and consume Watts of radio frequency power. Here, we
demonstrate an integrated 3-GHz acousto-optic frequency shifter on thin-film
lithium niobate, featuring a carrier suppression over 30 dB. Further, we
demonstrate a gigahertz-spaced optical frequency comb featuring more than 200
lines over a 0.6-THz optical bandwidth by recirculating the light in an active
frequency shifting loop. Our integrated acousto-optic platform leads to the
development of on-chip optical routing, isolation, and microwave signal
processing
MS2 bacteriophage capsid studied using all-atom molecular dynamics
The all-atom model of an MS2 bacteriophage particle without its genome (the capsid) was built using high-resolution cryo-electron microscopy (EM) measurements for initial conformation. The structural characteristics of the capsid and the dynamics of the surrounding solution were examined using molecular dynamics simulation. The model demonstrates the overall preservation of the cryo-EM structure of the capsid at physiological conditions (room temperature and ions composition). The formation of a dense anion layer near the inner surface and a diffuse cation layer near the outer surface of the capsid was detected. The flow of water molecules and ions across the capsid through its pores were quantified, which was considerable for water and substantial for ions
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Genomes, expression profiles, and diversity of mitochondria of the White-footed Deermouse Peromyscus leucopus, reservoir of Lyme disease and other zoonoses.
The cricetine rodents Peromyscus leucopus and P. maniculatus are key reservoirs for several zoonotic diseases in North America. We determined the complete circular mitochondrial genome sequences of representatives of 3 different stock colonies of P. leucopus, one stock colony of P. maniculatus and two wild populations of P. leucopus. The genomes were syntenic with that of the murids Mus musculus and Rattus norvegicus. Phylogenetic analysis confirmed that these two Peromyscus species are sister taxa in a clade with P. polionotus and also uncovered a distinction between P. leucopus populations in the eastern and the central United States. In one P. leucopus lineage four extended regions of mitochondrial pseudogenes were identified in the nuclear genome. RNA-seq analysis revealed transcription of the entire genome and differences from controls in the expression profiles of mitochondrial genes in the blood, but not in liver or brain, of animals infected with the zoonotic pathogen Borrelia hermsii. PCR and sequencing of the D-loop of the mitochondrion identified 32 different haplotypes among 118 wild P. leucopus at a Connecticut field site. These findings help to further establish P. leucopus as a model organism for studies of emerging infectious diseases, ecology, and in other disciplines
Fault detection for modular multilevel converters based on sliding mode observer
This letter presents a fault detection method for modular multilevel converters (MMC) which is capable of lo¬cating a faulty semiconductor switching device in the circuit. The proposed fault detection method is based on a sliding mode observer (SMO) and a switching model of a half-bridge, the approach taken is to conjecture the location of fault, modify the SMO accordingly and then compare the observed and measured states to verify, or otherwise, the assumption. This technique requires no additional measurement elements and can easily be implemented in a DSP or micro-controller. The operation and robustness of the fault detection technique are confirmed by simulation results for the fault condition of a semiconductor switching device appearing as an open-circuit
Robustness analysis and experimental validation of a fault detection and isolation method for the modular multilevel converter
This paper presents a fault detection and isolation (FDI) method for open-circuit faults of power semiconductor devices in a modular multilevel converter (MMC). The proposed FDI method is simple with only one sliding mode observer (SMO) equation and requires no additional transducers. The method is based on an SMO for the circulating current in an MMC. An open-circuit fault of power semiconductor device is detected when the observed circulating current diverges from the measured one. A fault is located by employing an assumption-verification process. To improve the robustness of the proposed FDI method, a new technique based on the observer injection term is introduced to estimate the value of the uncertainties and disturbances, this estimated value can be used to compensate the uncertainties and disturbances. As a result, the proposed FDI scheme can detect and locate an open-circuit fault in a power semiconductor device while ignoring parameter uncertainties, measurement error and other bounded disturbances. The FDI scheme has been implemented in a field programmable gate array (FPGA) using fixed point arithmetic and tested on a single phase MMC prototype. Experimental results under different load conditions show that an open-circuit faulty power semiconductor device in an MMC can be detected and located in less than 50ms
Ab Initio No Core Shell Model with Leadership-Class Supercomputers
Nuclear structure and reaction theory is undergoing a major renaissance with
advances in many-body methods, strong interactions with greatly improved links
to Quantum Chromodynamics (QCD), the advent of high performance computing, and
improved computational algorithms. Predictive power, with well-quantified
uncertainty, is emerging from non-perturbative approaches along with the
potential for guiding experiments to new discoveries. We present an overview of
some of our recent developments and discuss challenges that lie ahead. Our foci
include: (1) strong interactions derived from chiral effective field theory;
(2) advances in solving the large sparse matrix eigenvalue problem on
leadership-class supercomputers; (3) selected observables in light nuclei with
the JISP16 interaction; (4) effective electroweak operators consistent with the
Hamiltonian; and, (5) discussion of A=48 system as an opportunity for the
no-core approach with the reintroduction of the core.Comment: 23 pages, 7 figures, Conference Proceedings online at
http://ntse.khb.ru/files/uploads/2016/proceedings/Vary.pd
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