177 research outputs found
Equivariant infinite loop space theory, I. The space level story
We rework and generalize equivariant infinite loop space theory, which shows
how to construct G-spectra from G-spaces with suitable structure. There is a
naive version which gives naive G-spectra for any topological group G, but our
focus is on the construction of genuine G-spectra when G is finite.
We give new information about the Segal and operadic equivariant infinite
loop space machines, supplying many details that are missing from the
literature, and we prove by direct comparison that the two machines give
equivalent output when fed equivalent input. The proof of the corresponding
nonequivariant uniqueness theorem, due to May and Thomason, works for naive
G-spectra for general G but fails hopelessly for genuine G-spectra when G is
finite. Even in the nonequivariant case, our comparison theorem is considerably
more precise, giving a direct point-set level comparison.
We have taken the opportunity to update this general area, equivariant and
nonequivariant, giving many new proofs, filling in some gaps, and giving some
corrections to results in the literature.Comment: 94 page
2-Segal sets and the Waldhausen construction
It is known by results of Dyckerhoff–Kapranov and of Gálvez-Carrillo–Kock–Tonks that the output of the Waldhausen S • -construction has a unital 2-Segal structure. Here, we prove that a certain S • -functor defines an equivalence between the category of augmented stable double categories and the category of unital 2-Segal sets. The inverse equivalence is described explicitly by a path construction. We illustrate the equivalence for the known examples of partial monoids, cobordism categories with genus constraints and graph coalgebras
BioingenierĂa e ingenierĂa biomĂ©dica en Colombia: trasegando en sus inicios y en la construcciĂłn de su futuro
Invitado a que transmita la experiencia personal en el área de la bioingenierĂa e ingenierĂa biomĂ©dica, de aquellos
inicios y desarrollos que fueron dando madurez a esta disciplina profesional en Colombia, sus desafĂos y aportes, considero
importante en primer lugar contextualizar el punto de partida en esta área de la investigación y de la práctica profesional
Revisiting the black hole mass of M87* using VLT/MUSE Adaptive Optics Integral Field Unit data I: Ionized gas kinematics
The stellar dynamic-based black hole mass measurements of M87 are twice that
determined via ionized gas kinematics; the former is closer to the estimation
from the diameter of the gravitationally-lensed ring around the black hole.
Using deeper and more comprehensive ionized gas kinematic data, we aim to
better constrain the morphology and kinematics of the nuclear ionized gas, thus
gaining insights into the reasons behind the disagreement of the measurements.
We use both Narrow and Wide Field Mode integral field spectroscopic data from
the Multi Unit Spectroscopic Explorer instrument, to model the morphology and
kinematics of multiple ionized gas emission lines in the nucleus of M87. The
new deep dataset reveals complexities in the nuclear ionized gas kinematics.
Several ionized gas filaments can be traced down into the projected sphere of
influence. We also found evidence of a partially-filled biconical outflow. The
velocity isophotes of the ionized gas disk are twisted and the position angle
of the innermost gas disk tends toward a value perpendicular to the radio jet
axis. The complexity of the nuclear morphology and kinematics precludes the
measurement of an accurate black hole mass. The results support a 6.0 black hole in a 25\deg disk, rather than a 3.5 black hole in a 42\deg disk. The specific RIAF model
earlier proposed to reconcile the mass measurement discrepancy was also tested.
In general, Keplerian disk models perform better than the RIAF model when
fitting the sub-arcsec ionized gas disk. A disk inclination close to 25\deg for
the nuclear gas disk, and the warp in the sub-arcsec ionized gas disk, help to
reconcile the contradictory nature of the mass discrepancy between stellar and
ionized gas black hole masses, and the mis-orientation between the axes of the
ionized gas disk and the jet.Comment: 21 pages, 22 figures (5 of them in the appendix). Accepted in
Astronomy & Astrophysic
El rol de la GeografĂÂa y sus hibridaciones recientes frente a la crisis de sustentabilidad global
Texto resumen
Review of Contemporary Self-Assembled Systems for the Controlled Delivery of Therapeutics in Medicine.
The novel and unique design of self-assembled micro and nanostructures can be tailored and controlled through the deep understanding of the self-assembly behavior of amphiphilic molecules. The most commonly known amphiphilic molecules are surfactants, phospholipids, and block copolymers. These molecules present a dual attraction in aqueous solutions that lead to the formation of structures like micelles, hydrogels, and liposomes. These structures can respond to external stimuli and can be further modified making them ideal for specific, targeted medical needs and localized drug delivery treatments. Biodegradability, biocompatibility, drug protection, drug bioavailability, and improved patient compliance are among the most important benefits of these self-assembled structures for drug delivery purposes. Furthermore, there are numerous FDA-approved biomaterials with self-assembling properties that can help shorten the approval pathway of efficient platforms, allowing them to reach the therapeutic market faster. This review focuses on providing a thorough description of the current use of self-assembled micelles, hydrogels, and vesicles (polymersomes/liposomes) for the extended and controlled release of therapeutics, with relevant medical applications. FDA-approved polymers, as well as clinically and commercially available nanoplatforms, are described throughout the paper
Systematic Review of Explicit Instruments Measuring Nature Connectedness: What Do We Know and What is Next?
This systematic review assesses the methodological quality of manuscripts focusing on scales that explicitly measure nature connectedness. A literature search in six electronic databases was conducted using a search strategy based on PICO guidelines. Only peer-reviewed primary research available in English language, published between 2000 and 2021, meeting the scope of this review were included. Data from 35 studies were narratively analyzed. Their methodological quality was assessed using the COSMIN Risk of Bias checklist. Only five studies were rated as high/adequate quality. Based on the findings we make the following recommendations: (a) the need for the development of a more universal nature connectedness construct, (b) the requirement to increase the methodological quality of the scales, (c) the need to identify which the scales measure trait or state, (d) the need to increase the validate scales cross-culturally, and (e) the need to develop
scales that can be employed with non-adult samples
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