35 research outputs found
SOUTH POL: Revealing the Polarized Southern Sky
SOUTH POL will be a survey of the Southern sky in optical polarized light. It
will use a newly designed polarimetric module at an 80cm Robotic Telescope.
Telescope and polarimeter will be installed at CTIO, Chile, in late 2012. The
initial goal is to cover the sky south of declination -15{\deg} in two years of
observing time, aiming at a polarimetric accuracy \lesssim 0.1% down to V=15,
with a camera covering a field of about 2.0 square degrees. SOUTH POL will
impact areas such as Cosmology, Extragalactic Astronomy, Interstellar Medium of
the Galaxy and Magellanic Clouds, Star Formation, Stellar Envelopes, Stellar
explosions and Solar System, among others.Comment: To appear in "Stellar Polarimetry: from Birth to Death", Madison, WI,
AIP Conf. Proc., 2012 (J. Hoffman, B. Whitney & J. Bjorkman eds.). After it
is published, it will be found at http://www.aip.or
Prime Focus Spectrograph - Subaru's future -
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project has been endorsed by Japanese community as one of
the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea,
Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology
with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution.
Taking advantage of Subaru's wide field of view, which is further extended with
the recently completed Wide Field Corrector, PFS will enable us to carry out
multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A
microlens is attached at each fiber entrance for F-ratio transformation into a
larger one so that difficulties of spectrograph design are eased. Fibers are
accurately placed onto target positions by positioners, each of which consists
of two stages of piezo-electric rotary motors, through iterations by using
back-illuminated fiber position measurements with a wide-field metrology
camera. Fibers then carry light to a set of four identical fast-Schmidt
spectrographs with three color arms each: the wavelength ranges from 0.38
{\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving
power of 3000. Before and during the era of extremely large telescopes, PFS
will provide the unique capability of obtaining spectra of 2400
cosmological/astrophysical targets simultaneously with an 8-10 meter class
telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil,
Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and
NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki
Takami, Editors, Proc. SPIE 8446 (2012)
Enhancing Video Recommendation Using Multimedia Content
Video recordings are complex media types. When we watch a movie, we can effortlessly register a lot of details conveyed to us (by the author) through different multimedia channels, in particular, the audio and visual modalities. To date, majority of movie recommender systems use collaborative filtering (CF) models or content-based filtering (CBF) relying on metadata (e.g., editorial such as genre or wisdom of the crowd such as user-generated tags) at their core since they are human-generated and are assumed to cover the 'content semantics' of movies by a great degree. The information obtained from multimedia content and learning from muli-modal sources (e.g., audio, visual and metadata) on the other hand, offers the possibility of uncovering relationships between modalities and obtaining an in-depth understanding of natural phenomena occurring in a video. These discerning characteristics of heterogeneous feature sets meet users' differing information needs. In the context of this Ph.D. thesis [9], which is briefly summarized in the current extended abstract, approaches to automated extraction of multimedia information from videos and their integration with video recommender systems have been elaborated, implemented, and analyzed. Variety of tasks related to movie recommendation using multimedia content have been studied. The results of this thesis can motivate the fact that recommender system research can benefit from knowledge in multimedia signal processing and machine learning established over the last decades for solving various recommendation tasks
Prime Focus Spectrograph (PFS) for the Subaru telescope: Its start of the last development phase
PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru’s prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation
Progress with the Prime Focus Spectrograph for the Subaru Telescope: a massively multiplexed optical and near-infrared fiber spectrograph
The Prime Focus Spectrograph (PFS) is an optical/near-infrared multi-fiber
spectrograph with 2394 science fibers, which are distributed in 1.3 degree
diameter field of view at Subaru 8.2-meter telescope. The simultaneous wide
wavelength coverage from 0.38 um to 1.26 um, with the resolving power of 3000,
strengthens its ability to target three main survey programs: cosmology,
Galactic archaeology, and galaxy/AGN evolution. A medium resolution mode with
resolving power of 5000 for 0.71 um to 0.89 um also will be available by simply
exchanging dispersers. PFS takes the role for the spectroscopic part of the
Subaru Measurement of Images and Redshifts project, while Hyper Suprime-Cam
works on the imaging part. To transform the telescope plus WFC focal ratio, a
3-mm thick broad-band coated glass-molded microlens is glued to each fiber tip.
A higher transmission fiber is selected for the longest part of cable system,
while one with a better FRD performance is selected for the fiber-positioner
and fiber-slit components, given the more frequent fiber movements and tightly
curved structure. Each Fiber positioner consists of two stages of
piezo-electric rotary motors. Its engineering model has been produced and
tested. Fiber positioning will be performed iteratively by taking an image of
artificially back-illuminated fibers with the Metrology camera located in the
Cassegrain container. The camera is carefully designed so that fiber position
measurements are unaffected by small amounts of high special-frequency
inaccuracies in WFC lens surface shapes. Target light carried through the fiber
system reaches one of four identical fast-Schmidt spectrograph modules, each
with three arms. Prototype VPH gratings have been optically tested. CCD
production is complete, with standard fully-depleted CCDs for red arms and
more-challenging thinner fully-depleted CCDs with blue-optimized coating for
blue arms.Comment: 14 pages, 12 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy V, Suzanne K. Ramsay, Ian S. McLean, Hideki
Takami, Editors, Proc. SPIE 9147 (2014)
Determination of exacerbation predictors in patients with COPD in physical therapy - a longitudinal study
Background: Chronic obstructive pulmonary disease (COPD) typically presents the characteristic clinical condition of exacerbation, with more intense symptoms associated with greater functional loss and consequently lower chances of patient survival. Objectives: This study sought to determine the predictors of exacerbation, alone or in combination, in patients with chronic obstructive pulmonary disease (COPD) who received physical therapeutic treatment over 6 months. Method: This was an observational, longitudinal and prospective study in which 63 COPD patients residing within the municipality of SĂŁo Carlos, SP, Brazil were evaluated. These patients had COPD stages II and III and were entered into a physical therapy program, consisting of 3 periods of assessment over 6 months. We evaluated the occurrence of acute exacerbation as well as the patients' body mass index (BMI), fat-free mass (FFM), fat-free mass index, forced expiratory volume in 1 second (FEV1), dyspnea, distance walked (DW) in the 6-minute walk test (6MWT) and handgrip strength. Results: When applying Cox settings with each covariate separately, the results revealed 5% significance only for the DW in the 6MWT, which demonstrated an interaction between BMI and FFM. Comparison of the 3 periods of assessment across the covariates measured showed a significant difference only for the DW between evaluations in the 3rd and 6th months. Conclusion: Upon analyzing the predictors of risk over 6 months of follow-up in patients with COPD, we found that the DW in the 6MWT was associated with the risk of exacerbation, although this risk also depended on the covariates BMI and FFM
Validity of the Italian adaptation of the Tinnitus Handicap Inventory; focus on quality of life and psychological distress in tinnitus-sufferers
The aim of this study was to determine the validity of the Italian translation of the Tinnitus Handicap Inventory (THI) by Newman et al. in order to make this self-report measure of perceived tinnitus handicap available both for clinical and research purposes in our country and to contribute to its cross-cultural validation as a self-report measure of perceived severity of tinnitus. The Italian translation of the Tinnitus Handicap Inventory (THI) was administered to 100 outpatients suffering from chronic tinnitus, aged between 20 and 82 years, who attended the audiological tertiary centres of the University Hospital of Modena and the Regional Hospital of Treviso. No segregation of cases was made on audiometric results; patients suffering from vertigo and neurological diseases were excluded. Pyschoacoustic characteristics of tinnitus (loudness and pitch) were determined and all patients also completed the MOS 36-Item Short Form Health Survey to assess self-perceived quality of life and the Hospital Anxiety and Depression Scale as a measure of self-perceived levels of anxiety and depression. The THI-I showed a robust internal consistency reliability (Cronbach’s alpha = 0.91) that was only slightly lower than the original version (Tinnitus Handicap Inventory-US; Cronbach’s alpha = 0.93) and its Danish (Cronbach’s alpha = 0.93) and Portuguese (Cronbach’s alpha = 0.94) translations. Also its two subscales (Functional and Emotional) showed a good internal consistency reliability (Cronbach’s alpha = 0.85 and 0.86, respectively). On the other hand, the Catastrophic subscale showed an unacceptable internal consistency reliability as it is too short in length (5 items). A confirmatory factor analysis failed to demonstrate that the 3 subscales of the THI-I correspond to 3 different factors. Close correlations were found between the total score of the Italian translation of the Tinnitus Handicap Inventory and all the subscales of the MOS 36-Item Short Form Health Survey (SF-36) and the Hospital Anxiety and Depression Scale scores indicating a good construct validity. Moreover, these statistically significant correlations (p < 0.005) confirmed that the self-report tinnitus handicap is largely related to psychological distress and a deterioration in the quality of life. On the other hand, it was confirmed that the tinnitus perceived handicap is totally independent (p > 0.05) from its audiometrically-derived measures of loudness and pitch thus supporting previous studies that focused on the importance of non-auditory factors, namely somatic attention, psychological distress and coping strategies, in the generation of tinnitus annoyance. Finally the results of the present study suggest that the THI-I maintains its original validity and should be incorporated, together with other adequate psychometric questionnaires, in the audiological examination of patients suffering from tinnitus and that psychiatric counselling should be recommended for the suspected co-morbidity between tinnitus annoyance and psychological distress