2,779 research outputs found
Repository as a service (RaaS)
In his oft-quoted seminal paper ‘Institutional Repositories: Essential Infrastructure For Scholarship In The Digital Age’ Clifford Lynch (2003) described the Institutional Repository as “a set of services that a university offers to the members of its community for the management and dissemination of digital materials created by the institution and its community members.” This paper seeks instead to define the repository service at a more primitive level, without the specialism of being an ‘Institutional Repository’, and looks at how it can viewed as providing a service within appropriate boundaries, and what that could mean for the future development of repositories, our expectations of what repositories should be, and how they could fit into the set of services required to deliver an Institutional Repository service as describe by Lynch.<br/
Wideband Optical Filters with Small Gap Coupled Subwavelength Metal Structures
In this letter, we show that the bandwidth of optical band-stop filters made
of subwavelength metal structures can be significantly increased by the strong
plasmonic near-field coupling through the corners of the periodic metal
squares. The effect of small gap coupling on the spectral bandwidth is
investigated by varying the gap size between the metal squares. An equivalent
transmission line model is used to fit the transmission and reflection spectra
of the metal filters. The transmission line model can characterize well the
metal structures with the gap size larger than the near-field decay length.
However, it fails to model the transmission and reflection spectra when the gap
size reaches the decay range of the near-field in the small gaps
Herpes simplex keratitis: Challenges in diagnosis and clinical management
Herpes simplex virus is responsible for numerous ocular diseases, the most common of which is herpetic stromal keratitis. This is a recurrent infection of the cornea that typically begins with a subclinical infection of the cornea that establishes a latent infection of sensory ganglia, most often the trigeminal ganglia. Recurring infections occur when the virus is reactivated from latency and travels back to the cornea, where it restimulates an inflammatory response. This inflammatory response can lead to decreased corneal sensation, scarring, and blindness. The diagnosis of these lesions as the result of a recurrent herpes simplex virus infection can at times be problematic. Currently, herpetic stromal keratitis is diagnosed by its clinical presentation on the slit-lamp examination, but the literature does not always support the accuracy of these clinical findings. Other diagnostic tests such as polymerase chain reaction assay, enzyme-linked immunosorbent assay, immunofluorescent antibody, and viral cultures have provided more definitive diagnosis, but also have some limitations. That said, accurate diagnosis is necessary for proper treatment, in order to prevent serious consequences. Current treatment reduces the severity of lesions and controls further viral spread, but does not provide a cure
Impact of Simulated 1/f Noise for HI Intensity Mapping Experiments
Cosmology has entered an era where the experimental limitations are not due
to instrumental sensitivity but instead due to inherent systematic
uncertainties in the instrumentation and data analysis methods. The field of HI
intensity mapping (IM) is still maturing, however early attempts are already
systematics limited. One such systematic limitation is 1/f noise, which largely
originates within the instrumentation and manifests as multiplicative gain
fluctuations. To date there has been little discussion about the possible
impact of 1/f noise on upcoming single-dish HI IM experiments such as BINGO,
FAST or SKA. Presented in this work are Monte-Carlo end-to-end simulations of a
30 day HI IM survey using the SKA-MID array covering a bandwidth of 950 and
1410 MHz. These simulations extend 1/f noise models to include not just
temporal fluctuations but also correlated gain fluctuations across the receiver
bandpass. The power spectral density of the spectral gain fluctuations are
modelled as a power-law, and characterised by a parameter . It is found
that the degree of 1/f noise frequency correlation will be critical to the
success of HI IM experiments. Small values of ( < 0.25) or high
correlation is preferred as this is more easily removed using current component
separation techniques. The spectral index of temporal fluctuations ()
is also found to have a large impact on signal-to-noise. Telescope slew speed
has a smaller impact, and a scan speed of 1 deg s should be sufficient
for a HI IM survey with the SKA.Comment: 22 pages, 15 figures, 2 table
UNSWIRF: A Tunable Imaging Spectrometer for the Near-Infrared
We describe the specifications, characteristics, calibration, and analysis of
data from the University of New South Wales Infrared Fabry-Perot (UNSWIRF)
etalon. UNSWIRF is a near-infrared tunable imaging spectrometer, used primarily
in conjunction with IRIS on the AAT, but suitable for use as a visitor
instrument at other telescopes. The etalon delivers a resolving power in excess
of 4000 (corresponding to a velocity resolution ~75 km/s), and allows imaging
of fields up to 100" in diameter on the AAT at any wavelength between 1.5 and
2.4 microns for which suitable blocking filters are available.Comment: 16 pages, 10 figures, uses psfig.sty and html.sty (included). To
appear in Publications of the Astronomical Society of Australi
Standoff alpha radiation detection via excited state absorption of air
This is the published version. © Copyright 2013 AIP Publishing LLCA standoff alpha radiation detection technique based on the physical mechanism of excited state absorption of air molecules was explored and is presented in this paper. Instead of directly detecting the radiation via measuring the intensity of radiation induced air fluorescence, the radiation is detected via the excited state absorption of alpha radiation excited/ionized air molecules. Both theoretical analyses and experimental verifications were conducted. The experimental results confirmed that the radiation could be detected via excited state absorption of radiation excited/ionized air molecules at a 10 m standoff distance, which was consistent with the theoretical analyses
Dendritic Cell Autophagy Contributes to Herpes Simplex Virus-Driven Stromal Keratitis and Immunopathology
Herpetic stromal keratitis (HSK) is a blinding ocular disease that is initiated by HSV-1 and characterized by chronic inflammation in the cornea. Although HSK immunopathology of the cornea is well documented in animal models, events preceding this abnormal inflammatory cascade are poorly understood. In this study, we have examined the activation of pathological CD4T cells in the development of HSK. Dendritic cell autophagy (DC-autophagy) is an important pathway regulating ma- jor histocompatibility complex class II (MHCII)-dependent antigen presentation and proper CD4T cell activation during infectious diseases. Using DC-autophagy-deficient mice, we found that DC-autophagy significantly and specifically contributes to HSK disease without impacting early innate immune infiltration, viral clearance, or host survival. Instead, the observed phe- notype was attributable to the abrogated activation of CD4T cells and reduced inflammation in HSK lesions. We conclude that DC-autophagy is an important contributor to primary HSK immunopathology upstream of CD4T cell activation. IMPORTANCE Herpetic stromal keratitis (HSK) is the leading cause of infectious blindness in the United States and a rising cause worldwide. HSK is induced by herpes simplex virus 1 but is considered a disease of inappropriately sustained inflammation driven by CD4T cells. In this study, we investigated whether pathways preceding CD4T cell activation affect disease outcome. We found that autophagy in dendritic cells significantly contributed to the incidence of HSK. Dendritic cell autophagy did not alter immune control of the virus or neurological disease but specifically augmented CD4T cell activation and pathological corneal inflammation. This study broadens our understanding of the immunopathology that drives HSK and implicates the autophagy pathway as a new target for therapeutic intervention against this incurable form of infectious blindness
HI intensity mapping with FAST
We discuss the detectability of large-scale HI intensity fluctuations using
the FAST telescope. We present forecasts for the accuracy of measuring the
Baryonic Acoustic Oscillations and constraining the properties of dark energy.
The FAST -beam L-band receivers (-- GHz) can provide
constraints on the matter power spectrum and dark energy equation of state
parameters () that are comparable to the BINGO and CHIME
experiments. For one year of integration time we find that the optimal survey
area is . However, observing with larger frequency coverage
at higher redshift (-- GHz) improves the projected errorbars on the
HI power spectrum by more than confidence level. The combined
constraints from FAST, CHIME, BINGO and Planck CMB observations can provide
reliable, stringent constraints on the dark energy equation of state.Comment: 7 pages, 3 figures, submitted to "Frontiers in Radio Astronomy and
FAST Early Sciences Symposium 2015" conference proceedin
State detection of bond wires in IGBT modules using eddy current pulsed thermography
Insulated gate bipolar transistor (IGBT) modules are important safety critical components in electrical power systems. Bond wire lift-off, a plastic deformation between wire bond and adjacent layers of a device caused by repeated power/thermal cycles, is the most common failure mechanism in IGBT modules. For the early detection and characterization of such failures, it is important to constantly detect or monitor the health state of IGBT modules, and the state of bond wires in particular. This paper introduces eddy current pulsed thermography (ECPT), a nondestructive evaluation technique, for the state detection and characterization of bond wire lift-off in IGBT modules. After the introduction of the experimental ECPT system, numerical simulation work is reported. The presented simulations are based on the 3-D electromagnetic-thermal coupling finite-element method and analyze transient temperature distribution within the bond wires. This paper illustrates the thermal patterns of bond wires using inductive heating with different wire statuses (lifted-off or well bonded) under two excitation conditions: nonuniform and uniform magnetic field excitations. Experimental results show that uniform excitation of healthy bonding wires, using a Helmholtz coil, provides the same eddy currents on each, while different eddy currents are seen on faulty wires. Both experimental and numerical results show that ECPT can be used for the detection and characterization of bond wires in power semiconductors through the analysis of the transient heating patterns of the wires. The main impact of this paper is that it is the first time electromagnetic induction thermography, so-called ECPT, has been employed on power/electronic devices. Because of its capability of contactless inspection of multiple wires in a single pass, and as such it opens a wide field of investigation in power/electronic devices for failure detection, performance characterization, and health monitoring
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Hospital Surgical Volume, Utilization, Costs and Outcomes of Retroperitoneal Lymph Node Dissection for Testis Cancer
Objectives. Retroperitoneal lymph node dissection (RPLND) outcomes for testis cancer originate mostly from single-center series. We characterized population-based utilization, costs, and outcomes and assessed whether higher volume affects outcomes. Methods and Materials. Using the US Nationwide Inpatient Sample from 2001–2008, we identified 993 RPLND and used propensity score methods to assess utilization, costs, and inpatient outcomes based on hospital surgical volume. Results. 51.6% of RPLND were performed at hospitals where there were two or fewer cases per year. RPLND was more commonly performed at large urban teaching hospitals, where men were younger, more likely to be white and earning incomes exceeding the 50th percentile (all P ≤ .05). Higher hospital volumes were associated with fewer complications and more routine home discharges (all P ≤ .047). However, higher volume hospitals had more transfusions (P = .004) and incurred $1,435 more in median costs (P < .001). Limitations include inability to adjust for tumor characteristics and absence of outpatient outcomes. Conclusions. Sociodemographic differences exist between high versus low volume RPLND hospitals. Although higher volume hospitals had more transfusions and higher costs, perhaps due to more complex cases, they experienced fewer complications. However, most RPLND are performed at hospitals where there were two or fewer cases per year
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