586 research outputs found
Multiband Studies of the Optical Periodic Modulation in the X-Ray Binary SAX~J1808.4-3658 during Its Quiescence and 2008 Outburst
We report on time-resolved optical imaging of the X-ray binary SAX
J1808.4-3658 during its quiescent state and 2008 outburst. The binary,
containing an accretion-powered millisecond pulsar, has a large sinusoidal-like
modulation in its quiescent optical emission. We employ a Markov chain Monte
Carlo technique to fit our multi-band light curve data in quiescence with an
irradiated star model, and derive a tight constraint of deg on
the inclination angle of the binary system. The pulsar and its companion
are constrained to have masses of 0.97^{+0.31}_{-0.22} M_{\sun} and
0.04^{+0.02}_{-0.01} M_{\sun} (both 1 ranges), respectively. The
dependence of these results on the measurements of the companion's projected
radial velocity is discussed. We also find that the accretion disk had nearly
constant optical fluxes over a 500 day period in the quiescent state our
data covered, but started brightening 1.5 months before the 2008 outburst.
Variations in modulation during the outburst were detected in our four
observations made 7-12 days after the start of the outburst, and a
sinusoidal-like modulation with 0.2 mag amplitude changed to have a smaller
amplitude of 0.1 mag. The modulation variations are discussed. We estimate the
albedo of the companion during its quiescence and the outburst, which was
approximately 0 and 0.8 (for isotropic emission), respectively. This large
difference probably provides additional evidence that the neutron star in the
binary turns on as a radio pulsar in quiescence.Comment: 13 pages, 9 figures, 1 table, accepted for publication in Ap
Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Expanding Clinical Presentations Due to Variations in THOC2 mRNA Nuclear Export Factor
Multiple TREX mRNA export complex subunits (e.g., THOC1, THOC2, THOC5, THOC6, THOC7) have now been implicated in neurodevelopmental disorders (NDDs), neurodegeneration and cancer. We previously implicated missense and splicing-defective THOC2 variants in NDDs and a broad range of other clinical features. Here we report 10 individuals from nine families with rare missense THOC2 variants including the first case of a recurrent variant (p.Arg77Cys), and an additional individual with an intragenic THOC2 microdeletion (Del-Ex37-38). Ex vivo missense variant testing and patient-derived cell line data from current and published studies show 9 of the 14 missense THOC2 variants result in
Phenotypic, cytogenetic and spike fertility characterization of a population of male-sterile triticale
Recommended from our members
Capitalism in sustainability transitions research: time for a critical turn?
Sustainability transition research (STR) has failed to engage in any significant analyses or critiques of capitalism. This article argues that capitalism is not a ‘landscape’ factor, but rather permeates the workings of socio-technical systems in ways that must be recognised both for elaborating rigorous accounts of transition trajectories and for enhancing the capacity of STR to
support future societal sustainability transitions. This argument is developed specifically in relation to the three challenges of STR: the analysis of the actual sustainability of sustainability transitions, the application of transition theory to cases in the Global South, and the move towards a forward-looking STR. The article identifies three main implications of this argument with respect to interdisciplinarity, the validity of current theoretical frameworks, and the practice of STR. Ultimately, the article invites STR scholars to be more openly reflexive not only about
possible theoretical biases, but also regarding their own roles in society
Architecting graphene oxide rolled-up micromotors : a simple paper-based manufacturing technology
A graphene oxide rolled-up tube production process is reported using wax-printed membranes for the fabrication of on-demand engineered micromotors at different levels of oxidation, thickness, and lateral dimensions. The resultant graphene oxide rolled-up tubes can show magnetic and catalytic movement within the addition of magnetic nanoparticles or sputtered platinum in the surface of graphene-oxide-modified wax-printed membranes prior to the scrolling process. As a proof of concept, the as-prepared catalytic graphene oxide rolled-up micromotors are successfully exploited for oil removal from water. This micromotor production technology relies on an easy, operator-friendly, fast, and cost-efficient wax-printed paper-based method and may offer a myriad of hybrid devices and applications
A multinational Delphi consensus to end the COVID-19 public health threat
Publisher Copyright: © 2022, The Author(s).Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic1,2. Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19 response from 112 countries and territories to recommend specific actions to end this persistent global threat to public health. The panel developed a set of 41 consensus statements and 57 recommendations to governments, health systems, industry and other key stakeholders across six domains: communication; health systems; vaccination; prevention; treatment and care; and inequities. In the wake of nearly three years of fragmented global and national responses, it is instructive to note that three of the highest-ranked recommendations call for the adoption of whole-of-society and whole-of-government approaches1, while maintaining proven prevention measures using a vaccines-plus approach2 that employs a range of public health and financial support measures to complement vaccination. Other recommendations with at least 99% combined agreement advise governments and other stakeholders to improve communication, rebuild public trust and engage communities3 in the management of pandemic responses. The findings of the study, which have been further endorsed by 184 organizations globally, include points of unanimous agreement, as well as six recommendations with >5% disagreement, that provide health and social policy actions to address inadequacies in the pandemic response and help to bring this public health threat to an end.Peer reviewe
CD8+ T cells from a novel T cell receptor transgenic mouse induce liver-stage immunity that can be boosted by blood-stage infection in rodent malaria
To follow the fate of CD8+ T cells responsive to Plasmodium berghei ANKA (PbA) infection, we generated an MHC I-restricted TCR transgenic mouse line against this pathogen. T cells from this line, termed PbT-I T cells, were able to respond to blood-stage infection by PbA and two other rodent malaria species, P. yoelii XNL and P. chabaudi AS. These PbT-I T cells were also able to respond to sporozoites and to protect mice from liver-stage infection. Examination of the requirements for priming after intravenous administration of irradiated sporozoites, an effective vaccination approach, showed that the spleen rather than the liver was the main site of priming and that responses depended on CD8α+ dendritic cells. Importantly, sequential exposure to irradiated sporozoites followed two days later by blood-stage infection led to augmented PbT-I T cell expansion. These findings indicate that PbT-I T cells are a highly versatile tool for studying multiple stages and species of rodent malaria and suggest that cross-stage reactive CD8+ T cells may be utilized in liver-stage vaccine design to enable boosting by blood-stage infections
Origin and development of theater-headed valleys in the Atacama Desert, northern Chile: Morphological analogs to martian valley networks
- …