638 research outputs found
Automating the Surveillance of Mosquito Vectors from Trapped Specimens Using Computer Vision Techniques
Among all animals, mosquitoes are responsible for the most deaths worldwide.
Interestingly, not all types of mosquitoes spread diseases, but rather, a
select few alone are competent enough to do so. In the case of any disease
outbreak, an important first step is surveillance of vectors (i.e., those
mosquitoes capable of spreading diseases). To do this today, public health
workers lay several mosquito traps in the area of interest. Hundreds of
mosquitoes will get trapped. Naturally, among these hundreds, taxonomists have
to identify only the vectors to gauge their density. This process today is
manual, requires complex expertise/ training, and is based on visual inspection
of each trapped specimen under a microscope. It is long, stressful and
self-limiting. This paper presents an innovative solution to this problem. Our
technique assumes the presence of an embedded camera (similar to those in
smart-phones) that can take pictures of trapped mosquitoes. Our techniques
proposed here will then process these images to automatically classify the
genus and species type. Our CNN model based on Inception-ResNet V2 and Transfer
Learning yielded an overall accuracy of 80% in classifying mosquitoes when
trained on 25,867 images of 250 trapped mosquito vector specimens captured via
many smart-phone cameras. In particular, the accuracy of our model in
classifying Aedes aegypti and Anopheles stephensi mosquitoes (both of which are
deadly vectors) is amongst the highest. We present important lessons learned
and practical impact of our techniques towards the end of the paper
Kinematics of Nearby Subdwarf Stars
We present an analysis of the space motions of 742 subdwarf stars based on
the sample of Carney et al. (1994, CLLA). Hipparcos parallaxes, TYC2+HIP proper
motions and Tycho2 proper motions were combined with radial velocities and
metallicities from CLLA. The kinematical behavior is discussed in particular in
relation to their metallicities. The majority of these sample stars have metal
abundances of [Fe/H] >-1 and represent the thick disk population. The halo
component, with [Fe/H] <-1.6, is characterized by a low mean rotation velocity
and a radially elongated velocity ellipsoid. In the intermediate metallicity
range (-1.6 < [Fe/H] <-1), we find a significant number of subdwarfs with
disklike kinematics. We interpret this population of stars as a metal-weak
thick disk population.Comment: 6 pages, 7 figures, accepted by Astronomy & Astrophysic
The Many Faces of Risk: A Qualitative Study of Risk in Outpatient Involuntary Treatment.
Objective: This study aimed to derive a conceptualisation of risk in outpatient involuntary psychiatric treatment that has utility and meaning for stakeholders. Methods: Thirty-eight participants âpatients, caregivers, clinicians and legal decision makers â participated in qualitative interviews about their experiences of outpatient involuntary psychiatric treatment. Interview data was analysed using a general inductive method. Results: Six types of risk were identified: âactual harmâ, âsocial adversityâ, âtherapeutic outcome/compromised treatmentâ, âthe systemâ, âinterpersonal distressâ, and âepistemicâ. There were overlaps between the discourses on risk, but variation in how different aspects of risk were emphasised. Conclusions: Based on the findings, a comprehensive model of âriskâ contextualized to outpatient involuntary treatment is proposed. It incorporates the domains of ârisk of harm to self or othersâ; ârisk of social adversityâ; ârisk of excess distressâ; and, ârisk of compromised treatmentâ. This model may have instrumental value in the implementation and the scrutiny of risk-based mental health laws.funded by a discretionary grant from the Mental Health, Drug and Alcohol Office of NSW Healt
The lived experience of involuntary community treatment: a qualitative study of mental health consumers and carers
Objective: To describe the lived experiences of people subject to community treatment orders (CTOs) and their carers. Method: We recruited 11 participants (five mental health consumers and six carers) through consumer and carer networks in NSW, Australia, to take part in interviews about their experiences. We analysed the interview data set using established qualitative methodologies. Results: The lived experiences were characterised by âaccessâ concerns, âisolationâ, âloss and traumaâ, âresistance and resignationâ and âvulnerability and distressâ. The extent and impact of these experiences related to the severity of mental illness, the support available for people with mental illnesses and their carers, the social compromises associated with living with mental illness, and the challenges of managing the relationships necessitated by these processes. Conclusions: The lived experience of CTOs is complex: it is one of distress and profound ambivalence. The distress is an intrinsic aspect of the experience of severe mental illness, but it also emerges from communication gaps, difficulty obtaining optimal care and accessing mental health services. The ambivalence arises from an acknowledgement that while CTOs are coercive and constrain autonomy, they may also be beneficial. These findings can inform improvements to the implementation of CTOs and the consequent experiences. Keywords: carer, community treatment order, interview, involuntary treatment, mental health, patient experience, qualitative researchsupported by the Mental Health, Drug and Alcohol Office (MHDAO) of NSW Health of Australia
An Overview of the Rotational Behavior of Metal--Poor Stars
The present paper describes the behavior of the rotational velocity in
metal--poor stars ([Fe/H]<-0.5 dex) in different evolutionary stages, based on
Vsini values from the literature. Our sample is comprised of stars in the field
and some Galactic globular clusters, including stars on the main sequence, the
red giant branch (RGB), and the horizontal branch (HB). The metal--poor stars
are, mainly, slow rotators, and their Vsini distribution along the HR diagram
is quite homogeneous. Nevertheless, a few moderate to high values of Vsini are
found in stars located on the main sequence and on the HB. We show that the
overall distribution of Vsini values is basically independent of metallicity
for the stars in our sample. In particular, the fast-rotating main sequence
stars in our sample present similar rotation rates as their metal-rich
counterparts, suggesting that some of them may actually be fairly young, in
spite of their low metallicity, or else that at least some of them would be
better classified as blue straggler stars. We do not find significant evidence
of evolution in Vsini values as a function of position on the RGB; in
particular, we do not confirm previous suggestions that stars close to the RGB
tip rotate faster than their less evolved counterparts. While the presence of
fast rotators among moderately cool blue HB stars has been suggested to be due
to angular momentum transport from a stellar core that has retained significant
angular momentum during its prior evolution, we find that any such transport
mechanisms must likely operate very fast as the star arrives on the zero-age HB
(ZAHB), since we do not find a link between evolution off the ZAHB and Vsini
values.
We present an extensive tabulation of all quantities discussed in this paper,
including rotation velocities, temperatures, gravitieComment: 22 pages, 10 figure
A new species of the fish louse genus Dipteropeltis Calman, 1912 (Crustacea: Branchiura) from Peru
Dipteropeltis es un gĂ©nero poco descrito de piojo de los peces endĂ©mico de SudamĂ©rica. En una pequeña regiĂłn de aguas negras en Loreto, PerĂș, se observaron y recolectaron 13 especĂmenes adultos y juveniles de una especie no identificada de Dipteropeltis Calman, 1912, asĂ como un espĂ©cimen adulto de D. hirundo Calman, 1912. Se adquirieron micrografĂas electrĂłnicas y Ăłpticas de barrido para examinar y medir caracterĂsticas clave de estos especĂmenes. Las diferencias morfolĂłgicas con las dos especies conocidas de Dipteropeltis, D. hirundo y D. Dipteropeltis Neethling et al., 2014, indican que los especĂmenes recogidos representan una nueva especie. Dipteropeltis longicaudatus sp. nov. se distingue por sus lĂłbulos abdominales alargados, un caparazĂłn en forma de cresta y unos maxilares de forma Ășnica. Un espĂ©cimen representa el branquiuro mĂĄs largo documentado hasta la fecha, con 31,5 mm. AdemĂĄs, se proporcionan los primeros datos de secuencia para este gĂ©nero utilizando cĂłdigos de barras de ADN, lo que corrobora la designaciĂłn de una nueva especie. TambiĂ©n se grabaron vĂdeos que documentan comportamientos como la fijaciĂłn al hospedero, la pulsaciĂłn de los lĂłbulos abdominales, el "desplazamiento" del disco de succiĂłn y la nataciĂłn. Los hallazgos tienen implicaciones para sus hospederos teleĂłsteos, Triportheus albus Cope, 1872 y Brycon amazonicus Spix & Agassiz, 1829, siendo este Ășltimo una especie crĂtica para la acuicultura y la pesca comercial en la Amazonia.RevisiĂłn por pares
V474 Car: A Rare Halo RS CVn Binary in Retrograde Galactic Orbit
We report the discovery that the star V474 Car is an extremely active, high
velocity halo RS CVn system. The star was originally identified as a possible
pre-main sequence star in Carina, given its enhanced stellar activity, rapid
rotation (10.3 days), enhanced Li, and absolute magnitude that places it above
the main sequence. However, its extreme radial velocity (264 km s)
suggested that this system was unlike any previously known pre-MS system. Our
detailed spectroscopic analysis of echelle spectra taken with the CTIO 4-m
finds that V474 Car is both a spectroscopic binary with orbital period similar
to the photometric rotation period, and metal poor ([Fe/H] 0.99). The
star's Galactic orbit is extremely eccentric (e 0.93) with
perigalacticon of only 0.3 kpc of the Galactic center - and its
eccentricity and smallness of its perigalacticon are only surpassed by
0.05%, of local F/G-type field stars. The observed characteristics are
consistent with V474 Car being a high velocity, metal poor, tidally-locked
chromospherically active binary (CAB), i.e.\ a halo RS CVn binary, and one of
only a few such specimens known.Comment: Accepted to Astronomical Journa
Distances and ages of globular clusters using Hipparcos parallaxes of local subdwarfs
We discuss the impact of Population II and Globular Cluster (GCs) stars on
the derivation of the age of the Universe, and on the study of the formation
and early evolution of galaxies, our own in particular. The long-standing
problem of the actual distance scale to Population II stars and GCs is
addressed, and a variety of different methods commonly used to derive distances
to Population II stars are briefly reviewed. Emphasis is given to the
discussion of distances and ages for GCs derived using Hipparcos parallaxes of
local subdwarfs. Results obtained by different authors are slightly different,
depending on different assumptions about metallicity scale, reddenings, and
corrections for undetected binaries. These and other uncertainties present in
the method are discussed. Finally, we outline progress expected in the near
future.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles',
A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 22
pages including 3 tables and 2 postscript figures, uses Kluwer's crckapb.sty
LaTeX style file, enclose
Abundances of metal-weak thick-disc candidates
High resolution spectra of 5 candidate metal-weak thick-disc stars suggested
by Beers & Sommer-Larsen (1995) are analyzed to determine their chemical
abundances. The low abundance of all the objects has been confirmed with
metallicity reaching [Fe/H]=-2.9. However, for three objects, the astrometric
data from the Hipparcos catalogue suggests they are true halo members. The
remaining two, for which proper-motion data are not available, may have
disc-like kinematics. It is therefore clear that it is useful to address
properties of putative metal-weak thick-disc stars only if they possess full
kinematic data. For CS 22894-19 the abundance pattern similar to those of
typical halo stars is found, suggesting that chemical composition is not a
useful discriminant between thick-disc and halo stars. CS 29529-12 is found to
be C enhanced with [C/Fe]=+1.0; other chemical peculiarities involve the s
process elements: [Sr/Fe]=-0.65 and [Ba/Fe]=+0.62, leading to a high [Ba/Sr]
considerably larger than what is found in more metal-rich carbon-rich stars,
but similar to LP 706-7 and LP 625-44 discussed by Norris et al (1997a).
Hipparcos data have been used to calculate the space velocities of 25 candidate
metal-weak thick-disc stars, thus allowing us to identify 3 bona fide members,
which support the existence of a metal-poor tail of the thick-disc, at variance
with a claim to the contrary by Ryan & Lambert (1995).Comment: to be published in MNRA
Three-dimensional hydrodynamical simulations of red giant stars: semi-global models for the interpretation of interferometric observations
Context. Theoretical predictions from models of red giant branch stars are a
valuable tool for various applications in astrophysics ranging from galactic
chemical evolution to studies of exoplanetary systems. Aims. We use the
radiative transfer code OPTIM3D and realistic 3D radiative-hydrodynamical (RHD)
surface convection simulations of red giants to explore the impact of
granulation on interferometric observables. Methods. We compute intensity maps
for the 3D simulation snapshots in two filters: in the optical at 5000 \pm 300
{\AA} and in the K band 2.14 0.26 {\mu}m FLUOR filter, corresponding to
the wavelength-range of instruments mounted on the CHARA interferometer. From
the intensity maps, we construct images of the stellar disks, accounting for
center-to-limb variations. We then derive interferometric visibility amplitudes
and phases. We study their behavior with position angle and wavelength.
Results. We provide average limb-darkening coefficients for different
metallicities and wavelength-ranges. We detail the prospects for the detection
and characterization of granulation and center-to-limb variations of red giant
stars with today's interferometers. We find that the effect of
convective-related surface structures depends on metallicity and surface
gravity. We provided theoretical closure phases that should be incorporated
into the analysis of red giant planet companion closure phase signals. We
estimate 3D-1D corrections to stellar radii determination: 3D models are ~ 3.5%
smaller to ~ 1% larger in the optical with respect to 1D, and roughly 0.5 to
1.5% smaller in the infrared. Even if these corrections are small, they are
important to properly set the zero point of effective temperature scale derived
by interferometry and to strengthen the confidence of existing red giant
catalogues of calibrating stars for interferometry.Comment: Accepted for publication on Astronomy & Astrophysics, 14 pages, 13
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