215 research outputs found
Probing ISM Models with H-alpha observations
I review the capabilities of H observations to constrain some aspects
of the current models of the interstellar medium. In particular, it is shown
that turbulence is a necessary ingredient of any viable model, since most of
the energy produced by supernova explosions and ionizing radiation is stored in
kinetic form in the ISM. Various forms of turbulent energy dissipation,
including cloud collisions, are analyzed. Two additional aspects, concerning
the existence of galactic fountains and their relation with High Velocity
Clouds, and the extended ionized layer of spiral galaxies are discussed; some
crucial experiments are suggested.Comment: 9 pages, plain LaTeX, 5 figures; Invited Talk at the "AAO/UKST
Galactic Plane H-alpha Survey" International Workshop, Sydney, Australi
Towards Effective Human-AI Decision-Making: The Role of Human Learning in Appropriate Reliance on AI Advice
The true potential of human-AI collaboration lies in exploiting the complementary capabilities of humans and AI to achieve a joint performance superior to that of the individual AI or human, i.e., to achieve complementary team performance (CTP). To realize this complementarity potential, humans need to exercise discretion in following AIâs advice, i.e., appropriately relying on the AIâs advice. While previous work has focused on building a mental model of the AI to assess AI recommendations, recent research has shown that the mental model alone cannot explain appropriate reliance. We hypothesize that, in addition to the mental model, human learning is a key mediator of appropriate reliance and, thus, CTP. In this study, we demonstrate the relationship between learning and appropriate reliance in an experiment with 100 participants. This work provides fundamental concepts for analyzing reliance and derives implications for the effective design of human-AI decision-making
Searching for biological feedstock material: 3D printing of wood particles from house borer and drywood termite frass
Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of wood-based structures in a layer wise fashion using the Binder Jetting printing process. The quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ÏBulk = 0.67 g/cm3 and ÏTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing
Asteroid Distributions in the Ecliptic
We present analysis of the asteroid surface density distribution of main belt
asteroids (mean perihelion AU) in five ecliptic latitude
fields, -17 \gtsimeq \beta(\degr) \ltsimeq +15, derived from deep
\textit{Large Binocular Telescope} (LBT) band (85% completeness limit mag) and \textit{Spitzer Space Telescope} IRAC 8.0 \micron (80%
completeness limit Jy) fields enabling us to probe the 0.5--1.0
km diameter asteroid population. We discovered 58 new asteroids in the optical
survey as well as 41 new bodies in the \textit{Spitzer} fields. The derived
power law slopes of the number of asteroids per square degree are similar
within each \degr{} ecliptic latitude bin with a mean value of . For the 23 known asteroids detected in all four IRAC channels mean
albedos range from to . No low albedo asteroids
( \ltsimeq 0.1) were detected in the \textit{Spitzer} FLS fields,
whereas in the SWIRE fields they are frequent. The SWIRE data clearly samples
asteroids in the middle and outer belts providing the first estimates of these
km-sized asteroids' albedos. Our observed asteroid number densities at optical
wavelengths are generally consistent with those derived from the Standard
Asteroid Model within the ecliptic plane. However, we find an over density at
\beta \gtsimeq 5\degr{} in our optical fields, while the infrared number
densities are under dense by factors of 2 to 3 at all ecliptic latitudes.Comment: 35 pages including 5 figures, accepted to The Astronomical Journa
Smart Working. Frauen in FĂŒhrungspositionen stĂ€rken
Ziel des Projektes war die Entwicklung von Smart Working-Strategien, die zu einer besseren Work-Life-Balance fĂŒr FĂŒhrungskrĂ€fte fĂŒhren und damit Zugangsbarrieren fĂŒr Frauen in FĂŒhrungspositionen abbauen. Unter âSmart Workingâ verstehen wir den reflektierten Einsatz von Informations- und Kommunikationstechnologien (IKT) fĂŒr eine flexible, standortunabhĂ€ngige Zusammenarbeit. Auf Basis von Unternehmens-erfahrungen aus dem verstĂ€rkten Einsatz von IKT wĂ€hrend der Corona-Pandemie entwickelten wir partizipativ mit Unternehmen technische, organisatorische und rechtliche Richtlinien zur Nutzung von IKT, um Homeoffice und FĂŒhrung auf Distanz ohne Anspruch auf jederzeitige VerfĂŒgbarkeit umzusetzen. Die Ergebnisse wurden in einer abschlieĂenden Fachtagung und einem handlungsanleitenden Strategiepapier fĂŒr Arbeitnehmer:innen, BetriebsrĂ€te, Gewerkschaften und Unternehmen zur Diskussion gestellt und medial durch einen Podcast zusammengefasst.
The goal of the project was to develop smart working strategies that lead to a better work-life balance for managers and thus reduce access barriers for women in management positions. By "Smart Working" we mean the reflected use of information and communication technologies (ICT) for flexible, location-independent cooperation. Based on company experiences from the increased use of ICT during the Corona pandemic, we developed technical, organisational and legal guidelines for the use of ICT in a participatory approach with companies in order to improve home office and distance leadership. The results were discussed in a concluding symposium and an action-oriented strategy paper for employees, works councils, trade unions and employers, and summarized in the form of a podcast
Altered hippocampal morphology in unmedicated patients with major depressive illness
Despite converging evidence that major depressive illness is associated with both memory impairment and hippocampal pathology, findings vary widely across studies and it is not known whether these changes are regionally specific. In the present study we acquired brain MRIs (magnetic resonance images) from 31 unmedicated patients with MDD (major depressive disorder; mean age 39.2±11.9 years; 77% female) and 31 demographically comparable controls. Three-dimensional parametric mesh models were created to examine localized alterations of hippocampal morphology. Although global volumes did not differ between groups, statistical mapping results revealed that in MDD patients, more severe depressive symptoms were associated with greater left hippocampal atrophy, particularly in CA1 (cornu ammonis 1) subfields and the subiculum. However, previous treatment with atypical antipsychotics was associated with a trend towards larger left hippocampal volume. Our findings suggest effects of illness severity on hippocampal size, as well as a possible effect of past history of atypical antipsychotic treatment, which may reflect prolonged neuroprotective effects. This possibility awaits confirmation in longitudinal studies
Mass accretion to young stars triggered by flaring activity in circumstellar disks
Young low-mass stars are characterized by ejection of collimated outflows and
by circumstellar disks which they interact with through accretion of mass. The
accretion builds up the star to its final mass and is also believed to power
the mass outflows, which may in turn remove the excess angular momentum from
the star-disk system. However, although the process of mass accretion is a
critical aspect of star formation, some of its mechanisms are still to be fully
understood. A point not considered to date and relevant for the accretion
process is the evidence of very energetic and frequent flaring events in these
stars. Flares may easily perturb the stability of the disks, thus influencing
the transport of mass and angular momentum. Here we report on three-dimensional
magnetohydrodynamic modeling of the evolution of a flare with an idealized
non--equilibrium initial condition occurring near the disk around a rotating
magnetized star. The model takes into account the stellar magnetic field, the
gravitational force, the viscosity of the disk, the magnetic-field-oriented
thermal conduction (including the effects of heat flux saturation), the
radiative losses from optically thin plasma, and the coronal heating. We show
that, during its first stage of evolution, the flare gives rise to a hot
magnetic loop linking the disk to the star. The disk is strongly perturbed by
the flare: disk material evaporates under the effect of the thermal conduction
and an overpressure wave propagates through the disk. When the overpressure
reaches the opposite side of the disk, a funnel flow starts to develop there,
accreting substantial disk material onto the young star from the side of the
disk opposite to the flare.Comment: 14 pages, 10 Figures; accepted for publication on MNRAS. Version with
full resolution images can be found at
http://www.astropa.unipa.it/~orlando/PREPRINTS/sorlando_mnras.pd
The cool side of Lyman Alpha Emitters
We extend a previous study of Lyman Alpha Emitters (LAEs) based on
hydrodynamical cosmological simulations, by including two physical processes
important for LAEs: (a) Lyman Alpha and continuum luminosities produced by
cooling of collisionally excited HI in the galaxy, (b) dust formation and
evolution; we follow these processes on a galaxy-by-galaxy basis. HI cooling on
average contributes 16-18% of the Lyman Alpha radiation produced by stars, but
this value can be much higher in low mass LAEs and further increased if the HI
is clumpy. The continuum luminosity is instead almost completely dominated by
stellar sources. The dust content of galaxies scales with their stellar mass,
M_{dust} is proportional to M_*^0.7 and stellar metallicity, Z_*, such that
M_{dust} is proportional to Z_*^1.7. As a result, the massive galaxies have
Lyman Alpha escape fraction as low as f_alpha=0.1, with a LAE-averaged value
decreasing with redshift such that it is (0.33,0.23) at z =(5.7,6.6). The UV
continuum escape fraction shows the opposite trend with redshift, possibly
resulting from clumpiness evolution. The model successfully reproduces the
observed Lyman Alpha and UV luminosity functions at different redshifts and the
Lyman Alpha equivalent width scatter to a large degree, although the observed
distribution appears to be more more extended than the predicted one. We
discuss possible reasons for such tension.Comment: 9 pages, accepted for publication in MNRA
The Sun was not born in M 67
Using the most recent proper-motion determination of the old,
Solar-metallicity, Galactic open cluster M 67, in orbital computations in a
non-axisymmetric model of the Milky Way, including a bar and 3D spiral arms, we
explore the possibility that the Sun once belonged to this cluster. We have
performed Monte Carlo numerical simulations to generate the present-day orbital
conditions of the Sun and M 67, and all the parameters in the Galactic model.
We compute 3.5 \times 10^5 pairs of orbits Sun-M 67 looking for close
encounters in the past with a minimum distance approach within the tidal radius
of M 67. In these encounters we find that the relative velocity between the Sun
and M 67 is larger than 20 km/s. If the Sun had been ejected from M 67 with
this high velocity by means of a three-body encounter, this interaction would
destroy an initial circumstellar disk around the Sun, or disperse its already
formed planets. We also find a very low probability, much less than 10^-7, that
the Sun was ejected from M 67 by an encounter of this cluster with a giant
molecular cloud. This study also excludes the possibility that the Sun and M 67
were born in the same molecular cloud. Our dynamical results convincingly
demonstrate that M67 could not have been the birth cluster of our Solar System.Comment: Astronomical Journal accepted (35 pages, 9 figures
In Silico and In Vitro Evaluation of Bevacizumab Biosimilar MB02 as an Antitumor Agent in Canine Mammary Carcinoma
Canine mammary carcinomas (CMC) are associated with major aggressive clinical behavior and high mortality. The current standard of care is based on surgical resection, without an established effective treatment scheme, highlighting the urgent need to develop novel effective therapies. Vascular endothelial growth factor (VEGF) is a key regulator of tumor angiogenesis and progression in the majority of solid cancers, including human and canine mammary carcinomas. The first therapy developed to target VEGF was bevacizumab, a recombinant humanized monoclonal antibody, which has already been approved as an anticancer agent in several human cancers. The goal of this work was to establish the therapeutic value of MB02 bevacizumab biosimilar in CMC. First, through different in silico approaches using the MUSCLE multiple-sequence alignment tool and the FoldX protein design algorithm, we were able to predict that canine VEGF is recognized by bevacizumab, after showing an extremely high sequence similarity between canine and human VEGF. Further, by using an ELISA-based in vitro binding assay, we confirmed that MB02 biosimilar was able to recognize canine VEGF. Additionally, canine VEGF-induced microvascular endothelial cell proliferation was inhibited in a concentration-dependent manner by MB02 biosimilar. These encouraging results show a high potential for MB02 as a promising therapeutic agent for the management of CMC.Fil: Cardama, Georgina Alexandra. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de OncologĂa Molecular; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Bucci, Paula Lorena. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de OncologĂa Molecular; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Lemos, Jesus. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de OncologĂa Molecular; ArgentinaFil: Llavona, Candela. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de OncologĂa Molecular; ArgentinaFil: Benavente, Micaela Andrea. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa. Laboratorio de OncologĂa Molecular; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Tandil. Centro de InvestigaciĂłn Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de InvestigaciĂłn Veterinaria de Tandil. Provincia de Buenos Aires. GobernaciĂłn. Comision de Investigaciones CientĂficas. Centro de InvestigaciĂłn Veterinaria de Tandil; ArgentinaFil: HellmĂ©n, Eva. Gobierno de la Provincia de Buenos Aires. Hospital El Cruce Doctor Nestor Carlos Kirchner. Centro de Medicina Traslacional.; ArgentinaFil: Fara, MarĂa Laura. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de FisiopatologĂa. Laboratorio de EndocrinologĂa; ArgentinaFil: Medrano, Eduardo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de FisiopatologĂa. Laboratorio de EndocrinologĂa; ArgentinaFil: Spitzer, Eduardo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de FisiopatologĂa. Laboratorio de EndocrinologĂa; ArgentinaFil: Demarco, Ignacio A.. No especifĂca;Fil: Sabella, Patricia. No especifĂca;Fil: Garona, Juan. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
- âŠ