Design of Farthest-Point Masks for Image Halftoning

In an earlier paper, we briefly presented a new halftoning algorithm called farthest-point halftoning. In the present paper, this method is analyzed in detail, and a novel dispersion measure is defined to improve the simplicity and flexibility of the result. This new stochastic screen algorithm is loosely based on Kang's dispersed-dot ordered dither halftone array construction technique used as part of his microcluster halftoning method. Our new halftoning algorithm uses pixelwise measures of dispersion based on one proposed by Kang which is here modified to be more effective. In addition, our method exploits the concept of farthest-point sampling (FPS), introduced as a progressive irregular sampling method by Eldar et al. but uses a more efficient implementation of FPS in the construction of the dot profiles. The technique we propose is compared to other state-of-the-art dither-based halftoning methods in both qualitative and quantitative manners

Random Time Forward Starting Options

We introduce a natural generalization of the forward-starting options, first discussed by M. Rubinstein. The main feature of the contract presented here is that the strike-determination time is not fixed ex-ante, but allowed to be random, usually related to the occurrence of some event, either of financial nature or not. We will call these options {\bf Random Time Forward Starting (RTFS)}. We show that, under an appropriate "martingale preserving" hypothesis, we can exhibit arbitrage free prices, which can be explicitly computed in many classical market models, at least under independence between the random time and the assets' prices. Practical implementations of the pricing methodologies are also provided. Finally a credit value adjustment formula for these OTC options is computed for the unilateral counterparty credit risk.Comment: 19 pages, 1 figur

Effects of Conceptual Processing on Recognition and Conceptual Priming

The depth of encoding processes has been a variable of great importance in the study of the conscious correlates of memory. The presence of depth-of-processing effects in an intentional (direct or explicit) memory test has been interpreted as a marker of the engagement of voluntary retrieval associated with conscious recollection of the study episode. The absence of such effects in an incidental (indirect or implicit) memory test, where memory for previously encountered material is expressed as priming, has been interpreted as the marker of a form of involuntary retrieval. A problem arises in conceptual incidental tests, where priming is guided by a conceptual connection between the retrieval cue and the target memory, rather than by a perceptual connection. Depth-of-processing effects are usually reported in conceptual priming. The presence of such effects in conceptual priming creates problems for theories of the conscious correlates of memory in two main respects. In one respect, it is argued that dissociations between intentional and perceptual incidental tests are not due to the tests tapping voluntary and involuntary memory respectively, otherwise depth-of-processing effects would be absent in conceptual priming as well. The logic of this argument implies that the voluntary/involuntary dimension of memory is not an appropriate theoretical construct to explain the dissociations. In the second respect, depth-of-processing effects in priming have been interpreted as the results of contamination from a voluntary retrieval strategy and therefore they do not reflect involuntary memory. However, there are a small number of reports of an absence of depth-of-processing effects in conceptual incidental tests that undermine the arguments proposed above. In this thesis, the aim was to identify the circumstances under which depth-of-processing effects occur in conceptual incidental tests. Firstly, following Toth’s (1996) suggestion that familiarity in recognition memory is mediated by the same processes that mediate conceptual priming, the effects of depth-of-processing were investigated upon measures of familiarity. In Toth’s (1996) study, a speeded response procedure, designed to capture familiarity based responses, revealed an effect of depth of processing on familiarity, as in conceptual priming. Toth’s findings were replicated, but "Know" responses, collected in conjunction with the speeded responses, were found not to be susceptible to depth-of-processing effects. The implications of this finding are discussed. Depth-of- processing effects in conceptual incidental tests of word association were investigated next. In six different conditions, a dissociation was replicated between intentional tests and conceptual incidental tests following a manipulation of depth of processing at study. The manipulation had an effect on the retrieval of strong associates in the intentional test but not in the incidental test. This dissociation was replicated in older adults and was not an artefact of ceiling effects (as compound weak-associates did not show an effect of depth of processing) nor "response bias" (as this was equated between the two tests). A further experiment, in which study-test modality was manipulated, supported the hypothesis that the test tapped more conceptual processes. The absence of depth-of-processing effects could not be explained by this task tapping perceptual processes. The overall results make two major related points. Firstly, the dissociations support the idea that the involuntary/voluntary dichotomy in memory is still an important theoretical construct with explanatory power. Secondly, the dissociations go against the hypothesis that conceptual incidental tests are contaminated by voluntary retrieval strategies

Optical sensing in microchip capillary electrophoresis by femtosecond laser written waveguides

Capillary electrophoresis separation in an on-chip integrated microfluidic channel is typically monitored with bulky, bench-top optical excitation/detection instrumentation. Optical waveguides allow confinement and transport of light in the chip directing it to a small volume of the microfluidic channel and collecting the emitted/transmitted radiation. However, the fabrication of optical waveguides or more complex photonic components integrated with the microfluidic channels is not a straightforward process, since it requires a localized increase of the refractive index of the substrate.\ud Recently, a novel technique has emerged for the direct writing of waveguides and photonic circuits in transparent glass substrates by focused femtosecond laser pulses.\ud In this work we demonstrate the integration of femtosecond laser written optical waveguides into a commercial microfluidic chip. We fabricate high quality waveguides intersecting the microchannels at arbitrary positions and use them to optically address with high spatial selectivity their content. In particular, we apply our technique to integrate optical detection in microchip capillary electrophoresis. Waveguides are inscribed at the end of the separation channel in order to optically excite the different plugs reaching that point; fluorescence from the labelled biomolecules crossing the waveguide output is efficiently collected at a 90° angle by a high numerical aperture optical fiber. The sensitivity of the integrated optical detection system was first evaluated filling the chip with a dye solution, obtaining a minimum detectable concentration of 40 pM. \ud After dynamic coating of the microchannels with an EPDMA polymer we demonstrate electrophoresis of an oligonucleotide plug with concentration down to 1 nM and wavelength-selective monitoring of on-chip separation of three fluorescent dyes. Work is in progress on separation and detection of fluorescent-labeled DNA fragments, targeting specific, diagnostically relevant regions of a template DNA, for application to the detection of chromosome aberrations

General rules for bosonic bunching in multimode interferometers

We perform a comprehensive set of experiments that characterize bosonic bunching of up to 3 photons in interferometers of up to 16 modes. Our experiments verify two rules that govern bosonic bunching. The first rule, obtained recently in [1,2], predicts the average behavior of the bunching probability and is known as the bosonic birthday paradox. The second rule is new, and establishes a n!-factor quantum enhancement for the probability that all n bosons bunch in a single output mode, with respect to the case of distinguishable bosons. Besides its fundamental importance in phenomena such as Bose-Einstein condensation, bosonic bunching can be exploited in applications such as linear optical quantum computing and quantum-enhanced metrology.Comment: 6 pages, 4 figures, and supplementary material (4 pages, 1 figure

Fluorescence monitoring of capilarry electrophoresis separation in a lab-on-a-chip with monolithically integrated waveguides

Femtosecond-laser-written optical waveguides were monolithically integrated into a commercial lab-on-a-chip to intersect a microfluidic channel. Laser excitation through these waveguides confines the excitation window to a width of 12 μm, enabling high-spatial-resolution monitoring of different fluorescent analytes, during their migration/separation in the microfluidic channel by capillary electrophoresis. Wavelength-selective monitoring of the on-chip separation of fluorescent dyes is implemented as a proof-of-principle. We envision well-controlled microfluidic plug formation, waveguide excitation, and a low limit of detection to enable monitoring of extremely small quantities with high spatial resolution

Motor learning principles during rehabilitation after anterior cruciate ligament injury:Time to create an enriched environment to improve clinical outcome

Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or a reduced risk of subsequent injuries. A rising concern is the high rate of secondary ACL injuries, particularly in young athletes, with up to 40% of those returning to sport in the first year after surgery experiencing a second ACL rupture. Aside from the increased risk of secondary injury, patients after ACLR have an increased risk of developing early-onset osteoarthritis. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in terms of addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high reinjury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of secondary ACL injury. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce the risk of secondary ACL injury and early development of osteoarthritis by targeting changes in neural networks.</p

Multi-point, multi-wavelength fluorescence monitoring of DNA separation in a lab-on-a-chip with monolithically integrated femtosecond-laser-written waveguides

Electrophoretic separation of fluorescently labeled DNA molecules in on-chip microfluidic channels was monitored by integrated waveguide arrays, with simultaneous spatial and wavelength resolution. This is an important step toward point-of-care diagnostics with multiplexed DNA assays