3,210 research outputs found
Stellar structures in the outer regions of M33
We present Subaru/Suprime-Cam deep V and I imaging of seven fields in the
outer regions of M33. Our aim is to search for stellar structures corresponding
to extended HI clouds found in a recent 21-cm survey of the galaxy. Three
fields probe a large HI complex to the southeastern (SE) side of the galaxy. An
additional three fields cover the northwestern (NW) side of the galaxy along
the HI warp. A final target field was chosen further north, at a projected
distance of approximately 25 kpc, to study part of the large stellar plume
recently discovered around M33. We analyse the stellar population at R > 10 kpc
by means of V, I colour magnitude diagrams reaching the red clump. Evolved
stellar populations are found in all fields out to 120' (~ 30 kpc), while a
diffuse population of young stars (~ 200 Myr) is detected out to a
galactocentric radius of 15 kpc. The mean metallicity in the southern fields
remains approximately constant at [M/H] = -0.7 beyond the edge of the optical
disc, from 40' out to 80'. Along the northern fields probing the outer \hi
disc, we also find a metallicity of [M/H] = -0.7 between 35' and 70' from the
centre, which decreases to [M/H] = -1.0 at larger angular radii out to 120'. In
the northernmost field, outside the disc extent, the stellar population of the
large stellar feature possibly related to a M33-M31 interaction is on average
more metal-poor ([M/H] = -1.3) and older (> 6 Gyr). An exponential disc with a
large scale-length (~ 7 kpc) fits well the average distribution of stars
detected in both the SE and NW regions from a galactocentric distance of 11 kpc
out to 30 kpc. The stellar distribution at large radii is disturbed and,
although there is no clear correlation between the stellar substructures and
the location of the HI clouds, this gives evidence for tidal interaction or
accretion events.Comment: 13 pages, 13 figures. Accepted for publications in Astronomy and
Astrophysics; minor revisions of the tex
RLupus: Cooperation through emergent communication in <i>The Werewolf</i> social deduction game
Criscianthus, a new genus of Eupatorieae (Asteraceae) with a key to members of the tribe in Africa
Stomatanthes zambiensis is segregated from the African genus Stomatanthes and raised as the only species of the new genus Criscianthus (Eupatorieae, Asteraceae). Criscianthus zambiensis is characterized by its verticillate phyllotaxy with three leaves per node, phyllaries with caudate apex, and an exclusive type of hair in its cypsela. A full description of the genus and its species, a morphological analysis, photographs, illustrations, and a distribution map are provided. A key to native and alien species of the tribe Eupatorieae in Africa is included.Se segrega a Stomatanthes zambiensis del género africano Stomatanthes y se eleva como la única especie del nuevo género Criscianthus (Eupatorieae, Asteraceae). Criscianthus zambiensis se caracteriza por su filotaxis verticilada con tres hojas por nudo, filarias con el ápice caudado y un tipo exclusivo de pelo en su cipsela. Se incluye una descripción completa del género y de su especie, un análisis morfológico, fotografías, ilustraciones y un mapa de distribución. También se incluye una clave de las especies nativas y adventicias de Eupatorieae en África.Fil: Grossi, Mariana Andrea. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Katinas, Liliana. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nakajima, Jimi N.. Universidade Federal de Uberlândia; Brasi
The role of haptic feedback in video-Assisted thoracic surgery simulation training
technological advances on haptic devices, together with further studies focused on haptic feedback, be useful to develop efficient and effective training curricula and for establishing the value of simulators with haptic feedback in training and assessing thoracic surgical skills
Bioelectrochemical Systems for the Treatment of Wastewater and Methane Production
Long-term spaceflight will require technology that is self-sustaining, while minimizing volume and mass. Bioelectrochemical systems (BES) have the ability to recover valuable resources, process waste, and generate a small amount of electrical current, via microorganisms, while satisfying the above criteria. We are currently working on small scale BES reactors that will generate electricity from the breakdown of urine and utilize the electrical current to catalyze synthesis of products including water and methane
From Theory to Practice: Plug and Play with Succinct Data Structures
Engineering efficient implementations of compact and succinct structures is a
time-consuming and challenging task, since there is no standard library of
easy-to- use, highly optimized, and composable components. One consequence is
that measuring the practical impact of new theoretical proposals is a difficult
task, since older base- line implementations may not rely on the same basic
components, and reimplementing from scratch can be very time-consuming. In this
paper we present a framework for experimentation with succinct data structures,
providing a large set of configurable components, together with tests,
benchmarks, and tools to analyze resource requirements. We demonstrate the
functionality of the framework by recomposing succinct solutions for document
retrieval.Comment: 10 pages, 4 figures, 3 table
Cover crop introduction in a Mediterranean maize cropping system. Effects on soil variables and yield
Cover crops (CCs) are able to affect subsequent crop behaviour by acting on many soil
variables and affecting the dynamics of different ecological processes. This study aimed to investigate
the effects of introducing CC in continuous-maize cropping systems within Mediterranean areas. The
experimental site was located in Central Italy, on a sandy loam and the research activity was carried
out over two years (2019–2020). The two cropping systems in comparison differed from each other
in terms of the CC cultivation: TR (treated, with CC) and CO (control, without CC). In both years,
we observed a significant reduction (p < 0.05) of soil nitrate and water content for the TR system. In
the shallowest layer (0–30 cm), nitrate content was reduced by up 80% and 65% (July 2019 and
2020), whereas soil moisture showed decreases ranging from 13% (July 2019) to 34% (May 2019).
In 2019, the TR-maize (Zea mays L.) yield was statistically lower than CO (443 g dm m2), whereas
in 2020 the yields of the two systems resulted statistically equivalent. This different behaviour can
be explained with the serious delay in the CC sowing occurred in 2019 (12 December). Conversely,
an increase in the apparent remaining N in the soil (+140 and +133 kg N ha1 for 2019 and 2020,
respectively) and in the C (carbon) inputs (+4.78 and +7.39 t dm ha1 of biomass) were pointed out
for the TR system. The large use of inputs in Mediterranean maize cropping systems limited some of
the benefits from CCs, but their suitability has to be evaluated by considering all the involved effects,
some of which need a long time to become appreciable
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