9,550 research outputs found
Compressive Pattern Matching on Multispectral Data
We introduce a new constrained minimization problem that performs template
and pattern detection on a multispectral image in a compressive sensing
context. We use an original minimization problem from Guo and Osher that uses
minimization techniques to perform template detection in a multispectral
image. We first adapt this minimization problem to work with compressive
sensing data. Then we extend it to perform pattern detection using a formal
transform called the spectralization along a pattern. That extension brings out
the problem of measurement reconstruction. We introduce shifted measurements
that allow us to reconstruct all the measurement with a small overhead and we
give an optimality constraint for simple patterns. We present numerical results
showing the performances of the original minimization problem and the
compressed ones with different measurement rates and applied on remotely sensed
data.Comment: Published in IEEE Transactions on Geoscience and Remote Sensin
The realizability of operations on homotopy groups concentrated in two degrees
The homotopy groups of a space are endowed with homotopy operations which
define the \Pi-algebra of the space. An Eilenberg-MacLane space is the
realization of a \Pi-algebra concentrated in one degree. In this paper, we
provide necessary and sufficient conditions for the realizability of a
\Pi-algebra concentrated in two degrees. We then specialize to the stable case,
and list infinite families of such \Pi-algebras that are not realizable.Comment: Version 2: Some minor corrections. A few changes to the exposition.
To appear in the Journal of Homotopy and Related Structure
Reforming the Unbargained Contract: Avoiding Bondholder Claims for Surprise Par Calls
Until the last couple of decades, interest rates remained relatively stable, thus providing little incentive for corporate borrowers to seek novel ways of redeeming purportedly non-callable bonds at par. But with the advent of junk bonds and periods of great interest rate volatility, issuers have been provided with powerful incentives to explore the relatively uncharted waters of par calls. This Article examines the authority for and legality of such par calls and ultimately proposes a redefinition of the issuer-bondholder relationship. This redefinition accounts for the realities of the marketplace and should lead a return to more settled expectations in both issuer and investor camps. Along the way, the redefinition suggests a principled framework within which to litigate disputes when they arise, without resort to artificial constructs based on bargaining that does not actually take place or unsatisfactory contort theories
Suppressed antinodal coherence with a single d-wave superconducting gap leads to two energy scales in underdoped cuprates
Conventional superconductors are characterized by a single energy scale, the
superconducting gap, which is proportional to the critical temperature Tc . In
hole-doped high-Tc copper oxide superconductors, previous experiments have
established the existence of two distinct energy scales for doping levels below
the optimal one. The origin and significance of these two scales are largely
unexplained, although they have often been viewed as evidence for two gaps,
possibly of distinct physical origins. By measuring the temperature dependence
of the electronic Raman response of Bi2Sr2CaCu2O8+d (Bi-2212) and HgBa2CuO4+d
(Hg-1201) crystals with different doping levels, we establish that these two
scales are associated with coherent excitations of the superconducting state
which disappears at Tc. Using a simple model, we show that these two scales do
not require the existence of two gaps. Rather, a single d-wave superconducting
gap with a loss of Bogoliubov quasiparticle spectral weight in the antinodal
region is shown to reconcile spectroscopic and transport measurements.Comment: 3 figure
Animal welfare and gender: a nexus in awareness and preference when choosing fresh beef meat?
The modern consumer is now more attentive towards animal welfare practices and this represents an important factor when purchasing meat, whereby ethical, sociological and economic implications are evaluated. In addition, the socio-demographic characteristics of consumers evidence different sensitivities with regard to selection patterns and consumption styles. This study aims to explore the role of Gender in beef meat purchasing preferences, assessing consumer awareness of responsibility towards animal welfare, through the use of cross-tabulation with χ2 to test the different behaviour of men and women and the use of principal component analysis and cluster analysis to classify attitudes of choice according to gender. Among the research aims, this study examined consumer attitudes towards certain 'ethically incorrect' animal products, as well as their awareness of the institutional responsibility in controlling animal welfare standards during the meat production process. The study conducted in Northwest Italy, involving 512 respondents, shows that women are more sensitive to AW aspects and place trust in those responsible for certification of animal welfare standards, such as veterinarians and consumer associations, and also shows that it is possible to identify an 'animal welfare sensitive' profile of meat consumer.HIGHLIGHTS Modern consumer evaluates ethical, sociological and economic implications in animal friendly meat purchasing process Gender affects awareness of the responsibilities of veterinary, public health control bodies and consumer associations to verify animal welfare Cluster highlighted consumer differences in perception towards animal welfar
TCR remote monitoring for the LHC technical infrastructure
The remote monitoring of the LHC technical infrastructure will mainly be done in CERN’s Technical Control Room (TCR). The technical infrastrucure consists of specialised equipment from different groups and divisions, mainly cooling and ventilation and electrical equipment. The responsibility for the definition, operation and maintenance of the equipment is covered by the relevant equipment group. However the monitoring and alerting for action in case of equipment failure is initiated by the TCR and is based on alarms that are sent by the equipment. This implies the correct integration of the equipment and the establishment of rules to follow during the commissioning and start-up of the equipment in order to ensure proper operation. This paper shows the integration possibilities and the different tasks and steps to follow by the different parties for smooth equipment integration and avoiding organizational problems
Interrogating Seyferts with NebulaBayes: Spatially probing the narrow-line region radiation fields and chemical abundances
NebulaBayes is a new Bayesian code that implements a general method of
comparing observed emission-line fluxes to photoionization model grids. The
code enables us to extract robust, spatially resolved measurements of
abundances in the extended narrow line regions (ENLRs) produced by Active
Galactic Nuclei (AGN). We observe near-constant ionization parameters but
steeply radially-declining pressures, which together imply that radiation
pressure regulates the ENLR density structure on large scales. Our sample
includes four `pure Seyfert' galaxies from the S7 survey that have extensive
ENLRs. NGC2992 shows steep metallicity gradients from the nucleus into the
ionization cones. An {\it inverse} metallicity gradient is observed in
ESO138-G01, which we attribute to a recent gas inflow or minor merger. A
uniformly high metallicity and hard ionizing continuum are inferred across the
ENLR of Mrk573. Our analysis of IC5063 is likely affected by contamination from
shock excitation, which appears to soften the inferred ionizing spectrum. The
peak of the ionizing continuum E_peak is determined by the nuclear spectrum and
the absorbing column between the nucleus and the ionized nebula. We cannot
separate variation in this intrinsic E_peak from the effects of shock or HII
region contamination, but E_peak measurements nevertheless give insights into
ENLR excitation. We demonstrate the general applicability of NebulaBayes by
analyzing a nuclear spectrum from the non-active galaxy NGC4691 using a HII
region grid. The NLR and HII region model grids are provided with NebulaBayes
for use by the astronomical community.Comment: Accepted for publication in ApJ; 29 pages with 10 figures and 3
table
Randomized clinical trial on epidural versus patient-controlled analgesia for laparoscopic colorectal surgery within an enhanced recovery pathway.
OBJECTIVE: To compare epidural analgesia (EDA) to patient-controlled opioid-based analgesia (PCA) in patients undergoing laparoscopic colorectal surgery.
BACKGROUND: EDA is mainstay of multimodal pain management within enhanced recovery pathways [enhanced recovery after surgery (ERAS)]. For laparoscopic colorectal resections, the benefit of epidurals remains debated. Some consider EDA as useful, whereas others perceive epidurals as unnecessary or even deleterious.
METHODS: A total of 128 patients undergoing elective laparoscopic colorectal resections were enrolled in a randomized clinical trial comparing EDA versus PCA. Primary end point was medical recovery. Overall complications, hospital stay, perioperative vasopressor requirements, and postoperative pain scores were secondary outcome measures. Analysis was performed according to the intention-to-treat principle.
RESULTS: Final analysis included 65 EDA patients and 57 PCA patients. Both groups were similar regarding baseline characteristics. Medical recovery required a median of 5 days (interquartile range [IQR], 3-7.5 days) in EDA patients and 4 days (IQR, 3-6 days) in the PCA group (P = 0.082). PCA patients had significantly less overall complications [19 (33%) vs 35 (54%); P = 0.029] but a similar hospital stay [5 days (IQR, 4-8 days) vs 7 days (IQR, 4.5-12 days); P = 0.434]. Significantly more EDA patients needed vasopressor treatment perioperatively (90% vs 74%, P = 0.018), the day of surgery (27% vs 4%, P < 0.001), and on postoperative day 1 (29% vs 4%, P < 0.001), whereas no difference in postoperative pain scores was noted.
CONCLUSIONS: Epidurals seem to slow down recovery after laparoscopic colorectal resections without adding obvious benefits. EDA can therefore not be recommended as part of ERAS pathways in laparoscopic colorectal surgery
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