2,940 research outputs found

    Limits to Transits of the Neptune-mass planet orbiting Gl 581

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    We have monitored the Neptune-mass exoplanet-hosting M-dwarf Gl 581 with the 1m Swope Telescope at Las Campanas Observatory over two predicted transit epochs. A neutral density filter centered at 550nm was used during the first epoch, yielding 6.33 hours of continuous light curve coverage with an average photometric precision of 1.6 mmags and a cadence of 2.85 min. The second epoch was monitored in B-band over 5.85 hours, with an average photometric precision of 1.2 mmags and 4.28 min cadence. No transits are apparent on either night, indicating that the orbital inclination is less than 88.1 deg for all planets with radius larger than 0.38 R_Nep = 1.48 R_Earth. Because planets of most reasonable interior composition have radii larger than 1.55 R_Earth we place an inclination limit for the system of 88.1 deg. The corresponding minimum mass of Gl 581b remains 0.97 M_Nep = 16.6 M_Earth.Comment: 7 pages, 2 figures, 1 table, to appear in PAS

    The C IV Mass Density of the Universe at Redshift 5

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    In order to search for metals in the Lyman alpha forest at redshifts z > 4, we have obtained spectra of high S/N and resolution of three QSOs at z > 5.4 discovered by the Sloan Digital Sky Survey. These data allow us to probe to metal enrichment of the intergalactic medium at early times with higher sensitivity than previous studies. We find 16 C IV absorption systems with column densities log N(C IV) = 12.50 - 13.98 over a total redshift path Delta X = 3.29. In the redshift interval z = 4.5-5.0, where our statistics are most reliable, we deduce a comoving mass density of C IV ions Omega(C IV) = (4.3 +/- 2.5) x 10(-8) (90% confidence limits) for absorption systems with log N(C IV) > 13.0 (for an Einstein-de Sitter cosmology with h = 0.65). This value of Omega(C IV) is entirely consistent with those measured at z < 4; we confirm the earlier finding by Songaila (2001) that neither the column density distribution of C IV absorbers nor its integral show significant redshift evolution over a period of time which stretches from 1.25 to 4.5 Gyr after the big bang. This somewhat surprising conclusion may be an indication that the intergalactic medium was enriched in metals at redshifts much greater than 5, perhaps by the sources responsible for its reionization. Alternatively, the C IV systems we see may be associated with outflows from massive star-forming galaxies at later times, while the truly intergalactic metals may reside in regions of the Lyman alpha forest of lower density than those probed up to now.Comment: 24 pages including 5 figures. Accepted for publication in the Astrophysical Journal (September 10, 2003 issue

    Community Structure of Seagrass Molas Waters, Sub-district of Bunaken, Manado City of North Sulawesi

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    A study in community structure seagrass has been done in Molas, Manado City Area, with the aim : 1. To Identify seagrass species from Molas waters, 2. Knowing the community structure  of seagrass in this area, 3. Knowing the condition of aquatic environmental research location. 5 species from 2 families were found in this research i.e. Hydrocharitaceae (Halophila ovalis, Enhalus acoroides,  and Thalassia hemprichii) and Cymodoceaceae (Cymodocea rotundata, Syringodium isoetifolium). The important value of seagrass in the Molas waters showed that Syringodium isoetifolium had important value reaching were 127,31 %. Index of dominance was 0,335 which means no dominance seagrass in this area. The diversity index of seagrass was (H’) 1,328 which is relatively low. The distribution pattern value was 0,5, this shaved that distribution pattern. The temperature in this waters 29.75oC,  salinity 28.5 0/00, the substrate sand  muded  with good water conditions.Keywords: Seagrass; Molas; Identification; Community Structure; Importance Value Index AbstrakPenelitian tentang Struktur Komunitas lamun telah dilakukan di perairan pantai Kelurahan Molas, Kecamatan Bunaken Kota Manado, dengan tujuan: 1. Mengidentifikasi spesies lamun di perairan Molas, 2. Untuk mengetahui Struktur Komunitas Lamun 3. Mengetahui kondisi lingkungan perairan di lokasi penelitian. Lamun yang ditemukan di lokasi penelitian berjumlah 5 spesies dari 2 famili, Hydrocharitaceae (Halophila ovalis, Enhalus acoroides dan Thalassia hemprichii) dan Cymodoceaceae (Cymodocea rotundata dan Syringodium isoetifolium). Indeks nilai penting lamun di perairan Molas menunjukkan bahwa jenis Syringodium isoetifolium memiliki indeks nilai penting tertinggi yang mencapai 127,31 %. Nilai indeks dominansi menunjukkan nilai 0,335 yang berarti tidak ada lamun yang dominan. Indeks keanekaragaman spesies lamun menunjukkan nilai H’ 1,328 yang tergolong rendah. Pola distribusi yang diperoleh nilai 0,5 yang menunjukkan lamun di perairan Molas memiliki pola distribusi mengelompok. Hasil pengukuran parameter lingkungan di perairan Molas yaitu: suhu 29,75 oC, salinitas 28,5 0/00, substrat pasir berlumpur dengan kondisi perairan yang cukup jernih.Kata Kunci: Lamun; Molas; Identifikasi; Struktur Komunitas; Indeks Nilai Pentin

    Mobile safety alarms based on gps technology in the care of older adults:Systematic review of evidence based on a general evidence framework for digital health technologies

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    BackgroundGPS alarms aim to support users in independent activities. Previous systematic reviews have reported a lack of clear evidence of the effectiveness of GPS alarms for the health and welfare of users and their families and for social care provision. As GPS devices are currently being implemented in social care, it is important to investigate whether the evidence of their clinical effectiveness remains insufficient. Standardized evidence frameworks have been developed to ensure that new technologies are clinically effective and offer economic value. The frameworks for analyzing existing evidence of the clinical effectiveness of GPS devices can be used to identify the risks associated with their implementation and demonstrate key aspects of successful piloting or implementation. ObjectiveThe principal aim of this study is to provide an up-to-date systematic review of evidence based on existing studies of the effects of GPS alarms on health, welfare, and social provision in the care of older adults compared with non–GPS-based standard care. In addition, the study findings were assessed by using the evidence standards framework for digital health technologies (DHTs) established by the National Institute for Health and Care Excellence (NICE) in the United Kingdom. MethodsThis review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Primary studies published in peer-reviewed journals and gray literature from January 2005 to August 2020 were identified through searches in 13 databases and several sources of gray literature. Included studies had individuals (aged ≥50 years) who were receiving social care for older adults or for persons with dementia; used GPS devices as an intervention; were performed in Canada, the United States, European Union, Singapore, Australia, New Zealand, Hong Kong, South Korea, or Japan; and addressed quantitative outcomes related to health, welfare, and social care. The study findings were analyzed by using the NICE framework requirements for active monitoring DHTs. ResultsOf the screened records, 1.6% (16/986) were included. Following the standards of the NICE framework, practice evidence was identified for the tier 1 categories Relevance to current pathways in health/social care system and Acceptability with users, and minimum evidence was identified for the tier 1 category Credibility with health, social care professionals. However, several evidence categories for tiers 1 and 2 could not be assessed, and no clear evidence demonstrating effectiveness could be identified. Thus, the evidence required for using DHTs to track patient location according to the NICE framework was insufficient. ConclusionsEvidence of the beneficial effects of GPS alarms on the health and welfare of older adults and social care provision remains insufficient. This review illustrated the application of the NICE framework in analyses of evidence, demonstrated successful piloting and acceptability with users of GPS devices, and identified implications for future research

    Ballistic thermal phonons traversing nanocrystalline domains in oriented polyethylene

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    Thermally conductive polymer crystals are of both fundamental and practical interest for their high thermal conductivity that exceeds that of many metals. In particular, polyethylene fibers and oriented films with uniaxial thermal conductivity exceeding 50 W⋅m^(-1)⋅K^(-1) have been reported recently, stimulating interest into the underlying microscopic thermal transport processes. While ab initio calculations have provided insight into microscopic phonon properties for perfect crystals, such properties of actual samples have remained experimentally inaccessible. Here, we report the direct observation of thermal phonons with mean free paths up to 200 nm in semicrystalline polyethylene films using transient grating spectroscopy. Many of the mean free paths substantially exceed the crystalline domain sizes measured using small-angle X-ray scattering, indicating that thermal phonons propagate ballistically within and across the nanocrystalline domains; those transmitting across domain boundaries contribute nearly one-third of the thermal conductivity. Our work provides a direct determination of thermal phonon propagation lengths in molecular solids, yielding insights into the microscopic origins of their high thermal conductivity

    A Service Discovery Solution for Edge Choreography-Based Distributed Embedded Systems

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    [EN] This paper presents a solution to support service discovery for edge choreography based distributed embedded systems. The Internet of Things (IoT) edge architectural layer is composed of Raspberry Pi machines. Each machine hosts different services organized based on the choreography collaborative paradigm. The solution adds to the choreography middleware three messages passing models to be coherent and compatible with current IoT messaging protocols. It is aimed to support blind hot plugging of new machines and help with service load balance. The discovery mechanism is implemented as a broker service and supports regular expressions (Regex) in message scope to discern both publishing patterns offered by data providers and client services necessities. Results compare Control Process Unit (CPU) usage in a request¿response and datacentric configuration and analyze both regex interpreter latency times compared with a traditional message structure as well as its impact on CPU and memory consumption.The choreography engine was developed and supported by the SABIEN research group of the Universitat Politecnica de Valencia (http://www.sabien.upv.es/en/).Blanc Clavero, S.; Bayo-Monton, JL.; Palanca-Barrio, S.; Arreaga-Alvarado, NX. (2021). A Service Discovery Solution for Edge Choreography-Based Distributed Embedded Systems. Sensors. 21(2):1-19. https://doi.org/10.3390/s21020672S11921
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