4,087 research outputs found
Isotropic A-branes and the stability condition
The existence of a new kind of branes for the open topological A-model is
argued by using the generalized complex geometry of Hitchin and the SYZ picture
of mirror symmetry. Mirror symmetry suggests to consider a bi-vector in the
normal direction of the brane and a new definition of generalized complex
submanifold. Using this definition, it is shown that there exists generalized
complex submanifolds which are isotropic in a symplectic manifold. For certain
target space manifolds this leads to isotropic A-branes, which should be
considered in addition to Lagrangian and coisotropic A-branes. The Fukaya
category should be enlarged with such branes, which might have interesting
consequences for the homological mirror symmetry of Kontsevich. The stability
condition for isotropic A-branes is studied using the worldsheet approach.Comment: 19 page
Zonal circulation across 52°W in the North Atlantic
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C11008, doi:10.1029/2003JC002103.In July–August 1997, a hydrographic/Acoustic Doppler Current Profiler (ADCP)/tracer section was occupied along 52°W in the North Atlantic as part of the World Ocean Circulation Experiment Hydrographic Program. Underway and lowered ADCP (LADCP) data have been used to reference geostrophic velocities calculated from the hydrographic data; additional (small) velocity adjustments provided by an inverse model, constraining mass and silicate transports in 17 neutral density layers, yield the absolute zonal velocity field for 52°W. We find a vigorous circulation throughout the entire section, with an unusually strong Gulf Stream (169 Sv) and southern Deep Western Boundary Current (DWBC; 64 Sv) at the time of the cruise. At the northern boundary, on the west side of the Grand Banks of Newfoundland, we find the westward flowing Labrador Current (8.6 Sv), whose continuity from the Labrador Sea, east of our section, has been disputed. Directly to the south we identify the slopewater current (12.5 Sv eastward) and northern DWBC (12.5 Sv westward). Strong departures from strictly zonal flow in the interior, which are found in the LADCP data, make it difficult to diagnose the circulation there. Isolated deep property extrema in the southern portion, associated with alternating bands of eastward and westward flow, are consistent with the idea that the rough topography of the Mid-Atlantic Ridge, directly east of our section, causes enhanced mixing of Antarctic Bottom Water properties into overlying waters with distinctly different properties. We calculate heat and freshwater fluxes crossing 52°W that exceed estimates based on air-sea exchanges by a factor of 1.7.This work was supported by NSF grants
OCE95-29607, OCE 95-31864, OCE98-18266, and OCE-0219644
Thermodynamics of the quantum spin-S XXZ chain
The thermodynamics of the spin- anisotropic quantum chain with
arbitrary value of and unitary norm, in the high-temperature regime, is
reported. The single-ion anisotropy term and the interaction with an external
magnetic field in the -direction are taken into account. We obtain, for
arbitrary value of , the -expansion of the Helmholtz free energy of
the model up to order and show that it actually depends on
. Its classical limit is obtained by simply taking . At and D=0, our high temperature expansion of the classical
model coincides with Joyce's exact solution\cite{joyce_prl}. We study, in the
high temperature region, some thermodynamic quantities such as the specific
heat and the magnetic susceptibility as functions of spin and verify for which
values of those thermodynamic functions behave classically. Their finite
temperature behavior is inferred from interpolation of their high- and
low-temperature behavior, and shown to be in good agreement with numerical
results. The finite temperature behavior is shown for higher values of spin.Comment: 18 pages, 14 figure
Virtual Environment, Digital Hypertext, Reading and Writing in Foreign Language
This work intends to analyze - in an activity carried out with students from the third period of the Language (Spanish) undergraduate course of a college located in Itaperuna, a town in the State of Rio de Janeiro, Brazil - how the digital hyper textual reading can facilitate the selection of information in order to facilitate the writing process of texts in Spanish that can be broadcasted in the virtual environment, verifying how this may happen, so that these productions are shared, also allowing the interaction of the subjects with the language and with their peers. For this objective, we used the qualitative methodology (Erickson, 1986) with action research, seeking foundation in what theorists such as Lévy (1996, 1999), Coscarelli (2006, 2009), Gomes et al. (2015), Bannell et al. (2016), among others, investigate. As results, we emphasize that the subjects of the research actively participated in the construction of their own learning regarding the aspects covered in the foreign language class, and with this they were able to practice reading, writing, and the USAge of the vocabulary and grammar studied. Finally, we conclude that the hypertext worked here as an inclusive device, facilitator of reading and propitiator of writing, making the participant students authors of digital texts that provided them with learning throughout all the process they have been through
Neotropical Anacardiaceae (cashew family)
Anacardiaceae is an ecologically and economically important plant family of about 200 species in 32 genera in the Neotropics. The family is particularly diverse in leaf architecture and fruit morphology, making it a model family to study the evolution of structural diversity as it correlates with lineage diversification. This fruit diversity is the primary reason 11 of the Neotropical genera are monotypic and that so many genera are recognized in the Anacardiaceae. The economic value of the family is driven by the global markets for cashews, mangoes, and pistachios, but there is great potential value in its medicinal properties. At least 10 Neotropical genera cause contact dermatitis, which is a rich area for research in the family. Here presented is a review of the systematics and structural diversity of the family. Particular attention is given to the morphology, economic botany, paleobotany, ecology, and taxonomy of native and naturalized genera. Keys to Neotropical Anacardiaceae subfamilies and genera are provided along with descriptions of native genera
Bilayer mucoadhesive buccal film for mucosal ulcers treatment: development, characterization, and single study case
The formation of mucosal ulcers is an end result of epithelial damage, and it occurs due to some specific causes, such as trauma, aphthous stomatitis, lichen planus and lichenoid reactions, cytotoxic effects of chemotherapy and radiation, and drug-induced hypersensitivity reactions and malignant settings. This study focused on films for target drug delivery with respect to the treatment of the diseases of the oral mucosa, specifically mucositis. The results of a single clinical study as a pre-experimental design was performed and followed up to the outcome until 30 days. The polymeric film was prepared in a mucoadhesive bilayer structure: the basal layer with lidocaine HCl had a faster release than the apical layer with benzydamine HCl and N-acetyl-cysteine. Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and SEM characterized the physical–chemical and morphological properties. The cell viability and cytotoxicity were evaluated in cell line MCF7. The transport mechanism of the solvent (swelling) and the drugs in the basal or apical layer (drug release) was explained with mathematical models. To evaluate the effect of movement inside the mouth, the folding endurance was determined. The mucoadhesive bilayer film is biologically safe and stimulates cellular proliferation. A single study in vivo demonstrated the therapeutic effect of the mucoadhesive bilayer film in buccal mucositis.The authors express their gratitude to financial support from CAPES/PROSUP-Brazil;
Sao Paulo Research Foundation 2011/21219-5; Sao Paulo Research Foundation. 2018/13432-0; Sao Paulo Research Foundation. 2018/11350-6; National Council for Scientific and Technological Development (CNPq) 425271/2016-1.info:eu-repo/semantics/publishedVersio
Modeling the spectral energy distribution of ULIRGs I: the radio spectra
As a constraint for new starburst/AGN models of IRAS bright galaxies we
determine the radio spectra of 31 luminous and ultraluminous IRAS galaxies
(LIRGs/ULIRGs). We construct the radio spectra using both new and archival
data. From our sample of radio spectra we find that very few have a straight
power-law slope. Although some sources show a flattening of the radio spectral
slope at high frequencies the average spectrum shows a steepening of the radio
spectrum from 1.4 to 22.5 GHz. This is unexpected because in sources with high
rates of star formation we expect flat spectrum, free-free emission to make a
significant contribution to the radio flux at higher radio frequencies. Despite
this trend the radio spectral indices between 8.4 and 22.5 GHz are flatter for
sources with higher values of the FIR-radio flux density ratio q, when this is
calculated at 8.4 GHz. Therefore, sources that are deficient in radio emission
relative to FIR emission (presumably younger sources) have a larger thermal
component to their radio emission. However, we find no correlation between the
radio spectral index between 1.4 and 4.8 GHz and q at 8.4 GHz. Because the low
frequency spectral index is affected by free-free absorption, and this is a
function of source size for a given mass of ionized gas, this is evidence that
the ionized gas in ULIRGs shows a range of densities. The youngest LIRGs and
ULIRGs are characterized by a larger contribution to their high-frequency radio
spectra from free-free emission. However, the youngest sources are not those
that have the greatest free-free absorption at low radio frequencies. The
sources in which the effects of free-free absorption are strongest are instead
the most compact sources. Although these have the warmest FIR colours, they are
not necessarily the youngest sources.Comment: 16 pages. Submitted to A&A Re-submitted, with aesthetic improvements
to the text and figure
Safety and Immunogenicity of an In Vivo Muscle Electroporation Delivery System for DNA-hsp65 Tuberculosis Vaccine in Cynomolgus Monkeys
A Bacille Calmette–Guérin (BCG) is still the only licensed vaccine for the prevention of tuberculosis, providing limited protection against Mycobacterium tuberculosis infection in adulthood. New advances in the delivery of DNA vaccines by electroporation have been made in the past decade. We evaluated the safety and immunogenicity of the DNA-hsp65 vaccine administered by intramuscular electroporation (EP) in cynomolgus macaques. Animals received three doses of DNA-hsp65 at 30-day intervals. We demonstrated that intramuscular electroporated DNA-hsp65 vaccine immunization of cynomolgus macaques was safe, and there were no vaccine-related effects on hematological, renal, or hepatic profiles, compared to the pre-vaccination parameters. No tuberculin skin test conversion nor lung X-ray alteration was identified. Further, low and transient peripheral cellular immune response and cytokine expression were observed, primarily after the third dose of the DNA-hsp65 vaccine. Electroporated DNA-hsp65 vaccination is safe but provides limited enhancement of peripheral cellular immune responses. Preclinical vaccine trials with DNA-hsp65 delivered via EP may include a combination of plasmid cytokine adjuvant and/or protein prime–boost regimen, to help the induction of a stronger cellular immune response
It Takes Two to Tango, Part II : Synthesis of A-Ring Functionalised Quinones Containing Two Redox-Active Centres with Antitumour Activities
In 2021, our research group published the prominent anticancer activity achieved through
the successful combination of two redox centres (ortho-quinone/para-quinone or quinone/seleniumcontaining triazole) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The
combination of two naphthoquinoidal substrates towards a synergetic product was indicated, but
not fully explored. Herein, we report the synthesis of 15 new quinone-based derivatives prepared
from click chemistry reactions and their subsequent evaluation against nine cancer cell lines and
the murine fibroblast line L929. Our strategy was based on the modification of the A-ring of paranaphthoquinones and subsequent conjugation with different ortho-quinoidal moieties. As anticipated,
our study identified several compounds with IC50 values below 0.5 µM in tumour cell lines. Some
of the compounds described here also exhibited an excellent selectivity index and low cytotoxicity
on L929, the control cell line. The antitumour evaluation of the compounds separately and in their
conjugated form proved that the activity is strongly enhanced in the derivatives containing two
redox centres. Thus, our study confirms the efficiency of using A-ring functionalized para-quinones
coupled with ortho-quinones to obtain a diverse range of two redox centre compounds with potential
applications against cancer cell lines. Here as well, it literally takes two for an efficient tango
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