55,142 research outputs found
Webometric analysis of departments of librarianship and information science
This paper describes a webometric analysis of the linkages (or ‘sitations’) to websites associated with departments of librarianship and informaton science (LIS). Some of the observed sitation counts appear counter-intuitive and there is only a very limited correlation with peer evaluations of research performance, with many of the sitations being from pages that are far removed in subject matter from LIS. Our conclusions are that sitation data are now well suited to the quantitative evaluation of the research status of LIS departments and that departments can best boost their web visibility by hosting as wide a range of types of material as possible
Range-resolved interferometric signal processing using sinusoidal optical frequency modulation
A novel signal processing technique using sinusoidal optical frequency modulation of an inexpensive continuous-wave laser diode source is proposed that allows highly linear interferometric phase measurements in a simple, self-referencing setup. Here, the use of a smooth window function is key to suppress unwanted signal components in the demodulation process. Signals from several interferometers with unequal optical path differences can be multiplexed, and, in contrast to prior work, the optical path differences are continuously variable, greatly increasing the practicality of the scheme. In this paper, the theory of the technique is presented, an experimental implementation using three multiplexed interferometers is demonstrated, and detailed investigations quantifying issues such as linearity and robustness against instrument drift are performed
Fibre segment interferometry using code-division multiplexed optical signal processing for strain sensing applications
A novel optical signal processing scheme for multiplexing fibre segment interferometers is proposed. The continuous-wave, homodyne technique combines code-division multiplexing with single-sideband modulation. It uses only one electro-optic phase modulator to achieve both range separation and quadrature interferometric phase measurement. This scheme is applied to fibre segment interferometry, where a number of long-gauge length interferometric fibre sensors are formed by subtracting pairs of signals from equidistantly placed, weak back reflectors. In this work we give a detailed account of the signal processing involved and, in particular, explore aspects such as electronic bandwidth requirements, noise, crosstalk and linearity, which are important design considerations. A signal bandwidth of ±20 kHz permits the resolution of phase change rates of 2.5 × 104 rad s-1 for each of the four 16.5 m long segments in our setup. We show that dynamic strain resolutions below 0.2 nanostrain Hz-0.5 at 2 m sensor gauge length are achievable, even with an inexpensive diode laser. When used in applications that require only relative strain change measurements, this scheme compares well to more established techniques and can provide high-fidelity yet cost-effective measurements
Tackling the Global NCD Crisis: Innovations in Law and Governance
35 million people die annually of non-communicable diseases (NCDs), 80% of them in low- and middle-income countries—representing a marked epidemiological transition from infectious to chronic diseases and from richer to poorer countries. The total number of NCDs is projected to rise by 17% over the coming decade, absent significant interventions. The NCD epidemic poses unique governance challenges: the causes are multifactorial, the affected populations diffuse, and effective responses require sustained multi-sectorial cooperation. The authors propose a range of regulatory options available at the domestic level, including stricter food labeling laws, regulation of food advertisements, tax incentives for healthy lifestyle choices, changes to the built environment, and direct regulation of food and drink producers. Given the realities of globalization, such interventions require global cooperation. In 2011, the UN General Assembly held a High-level meeting on NCDs, setting a global target of a 25% reduction in premature mortality from NCDs by 2025. Yet concrete plans and resource commitments for reaching this goal are not yet in the offing, and the window is rapidly closing for achieving these targets through prevention--as opposed to treatment, which is more costly. Innovative global governance for health is urgently needed to engage private industry and civil society in the global response to the NCD crisis
Fair Is Fair—Reshaping Alaska’s Unfair Trade Practices and Consumer Protection Act
Few fields of law impact as wide a swath of population as consumer protection law. Alaska adopted its consumer protection statute, the Unfair Trade Practices and Consumer Protection Act (UTPCPA), amid a national movement to strengthen consumer protection laws. The UTPCPA uses broad language to encompass a wide range of conduct. However, creative pleading and recent applications of the UTPCPA have expanded the law in ways that threaten Alaska businesses even in the absence of culpable conduct. This Note reviews the history of consumer protection, Alaska’s UTPCPA, and the incentives leading to an expanding application of the UTPCPA. The Note concludes by proposing potential legislative solutions to rein in abuse of the Act
Objective speckle displacement: an extended theory for the small deformation of shaped objects
This paper describes an extended and improved theory of the displacement of the objective speckle pattern resulting from displacement and/or deformation of a coherently illuminated diffuse object. Using the theory developed by Yamaguchi [Opt. Acta 28, 1359 (1981)], extended expressions are derived that include the influence of surface shape/gradients via the first order approximation of the shape as linear surface gradients. Both the original Yamaguchi expressions and the extended form derived here are shown experimentally to break down as the detector position moves away from the z-axis. As such, improved forms of the expressions are then presented, which remove some of the approximations used by Yamaguchi and can be used to predict the objective speckle displacement over a wide range of detector positions and surface slopes. Finally, these expressions are then verified experimentally for the speckle shifts resulting from object translations
Full-field interferometry using infinity corrected optics
In this paper the construction of full-field (imaging) interferometers using infinity corrected
optics commonly used in microscopy is discussed, with an emphasis on self-mixing
interferometry configurations where the imaged light field is mixed with itself rather than
a reference wave. Such configurations are used in speckle shearing interferometry, flow
visualisation and quantitative flow measurement. The critical considerations for constructing
path-length imbalanced full-field interferometers for these and similar applications are
discussed, expressions are derived for key calculations and interferograms from example
interferometers are presented. These include the concept of balancing the infinity-spaces of
the two arms via the use of a glass block to minimise the optical path difference variation
across the interferogram and ensure adequate sampling of the fringes on the detector. Further,
the use of tilted glass blocks in single-pass and double-pass arrangements is detailed for
the generation and control of spatial carrier fringes without extensive realignment of the
interferometer, and for phase shifting
Objective speckle displacement resulting from the deformation of shaped objects
This paper describes an extended theory of the displacement of the objective speckle pattern resulting from displacement and/or deformation of a coherently illuminated diffuse object where the influence of the surface shape is included via the linear surface gradients. An experimental system capable of measuring the translational scaling factors, the ratios of speckle shift to object translations, to an accuracy of ± 0.02 and a repeatability of approximately ± 0.008 is described which was used to experimentally measure the speckle shift for a range of detector positions and surface gradients. The original expressions developed by Yamaguchi1 and the new extended expressions2 are then compared with experimental results for measurements on zero surface gradients, i.e. the mean surface lying in the x-y plane. The divergence of Yamaguchi’s expressions from experimental results for off-axis detector positions that was first observed by SvÄ›tlÃk3 was confirmed, and the new expressions shown to successfully predict translational scaling factors for off-axis positions. The new expressions are then compared to the experimental results for a range of surface gradient magnitudes and directions, as well as detector positions both on and off-axis, and shown to successfully predict the observed speckle shift.EPSR
Moral and Philosophic Problems of Modern Medicine: A Collegiate Program for Pre-Medical and Nursing Students
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