850 research outputs found
Lazy AC-Pattern Matching for Rewriting
We define a lazy pattern-matching mechanism modulo associativity and
commutativity. The solutions of a pattern-matching problem are stored in a lazy
list composed of a first substitution at the head and a non-evaluated object
that encodes the remaining computations. We integrate the lazy AC-matching in a
strategy language: rewriting rule and strategy application produce a lazy list
of terms.Comment: In Proceedings WRS 2011, arXiv:1204.531
State space c-reductions for concurrent systems in rewriting logic
We present c-reductions, a state space reduction technique.
The rough idea is to exploit some equivalence relation on states (possibly capturing system regularities) that preserves behavioral properties, and explore the induced quotient system. This is done by means of a canonizer
function, which maps each state into a (non necessarily unique) canonical representative of its equivalence class. The approach exploits the expressiveness of rewriting logic and its realization in Maude to enjoy several advantages over similar approaches: exibility and simplicity in
the definition of the reductions (supporting not only traditional symmetry reductions, but also name reuse and name abstraction); reasoning support for checking and proving correctness of the reductions; and automatization
of the reduction infrastructure via Maude's meta-programming
features. The approach has been validated over a set of representative case studies, exhibiting comparable results with respect to other tools
TYC 2675-663-1: A newly discovered W UMa system in an active state
The recently discovered eclipsing binary system TYC 2675-663-1 is a X-ray
source, and shows properties in the optical that are similar to the W UMa
systems, but are somewhat unusual compared to what is seen in other contact
binary systems. The goal of this work is to characterize its properties and
investigate its nature by means of detailed photometric and spectroscopic
observations. We have performed extensive V-band photometric measurements with
the INTEGRAL satellite along with ground-based multi-band photometric
observations, as well as high-resolution spectroscopic monitoring from which we
have measured the radial velocities of the components. These data have been
analysed to determine the stellar properties, including the absolute masses and
radii. Additional low-resolution spectroscopy was obtained to investigate
spectral features. From the measured eclipse timings we determine an orbital
period for the binary of P=0.4223576+-0.0000009 days. The light-curve and
spectroscopic analyses reveal the observations to be well represented by a
model of an overcontact system composed of main-sequence F5 and G7 stars
(temperature difference of nearly 1000 K), with the possible presence of a
third star. Low-resolution optical spectroscopy reveals a complex H alpha
emission, and other features that are not yet understood. The unusually large
mass ratio of q=0.81+-0.05 places it in the rare "H" (high mass ratio) subclass
of the W UMa systems, which are presumably on their way to coalescence.Comment: 12 pages in double column format. Accepted for publication in
Astronomy and Astrophysic
Unscheduled DNA synthesis in xeroderma pigmentosum cells after microinjection of yeast photoreactivating enzyme.
Photoreactivating enzyme (PRE) from yeast causes a light-dependent reduction of UV-induced unscheduled DNA synthesis (UDS) when injected into the cytoplasm of repair-proficieint human fibroblasts (Zwetsloot et al., 1985). This result indicates that the exogenous PRE monomerizers UV-induced dimers in these cells competing with the endogenous excision repair. In this paper we present the results of the injection of yeast PRE on (residual) UDS in fibroblasts from different excision-deficient XP-strains representing complementation groups A, C, D, E, F, H and I (all displaying more than 10% of the UDS of wild-type
Aperiodic optical variability of intermediate polars - cataclysmic variables with truncated accretion disks
We study the power spectra of the variability of seven intermediate polars
containing magnetized asynchronous accreting white dwarfs, XSS J00564+4548,IGR
J00234+6141, DO Dra, V1223 Sgr, IGR J15094-6649, IGR J16500-3307 and IGR
J17195-4100, in the optical band and demonstrate that their variability can be
well described by a model based on fluctuations propagating in a truncated
accretion disk. The power spectra have breaks at Fourier frequencies, which we
associate with the Keplerian frequency of the disk at the boundary of the white
dwarfs' magnetospheres. We propose that the properties of the optical power
spectra can be used to deduce the geometry of the inner parts of the accretion
disk, in particular: 1) truncation radii of the magnetically disrupted
accretion disks in intermediate polars, 2) the truncation radii of the
accretion disk in quiescent states of dwarf novaeComment: Accepted for publication in A&
Internet-based psychoeducation for bipolar disorder: a qualitative analysis of feasibility, acceptability and impact
<p>Background: In a recent exploratory randomised trial we found that a novel, internet-based psychoeducation programme for bipolar disorder (Beating Bipolar) was relatively easy to deliver and had a modest effect on psychological quality of life. We sought to explore the experiences of participants with respect to feasibility, acceptability and impact of Beating Bipolar.</p>
<p>Methods: Participants were invited to take part in a semi-structured interview. Thematic analysis techniques were employed; to explore and describe participants’ experiences, the data were analysed for emerging themes which were identified and coded.</p>
<p>Results: The programme was feasible to deliver and acceptable to participants where they felt comfortable using a computer. It was found to impact upon insight into illness, health behaviour, personal routines and positive attitudes towards medication. Many participants regarded the programme as likely to be most beneficial for those recently diagnosed.</p>
<p>Conclusions: An online psychoeducation package for bipolar disorder, such as Beating Bipolar, is feasible and acceptable to patients, has a positive impact on self-management behaviours and may be particularly suited to early intervention. Alternative (non-internet) formats should also be made available to patients.</p>
Cloning, tissue expression, and mapping of a human photolyase homolog with similarity to plant blue-light receptors
Enzymatic photoreactivation is a DNA repair mechanism that removes UV- induced pyrimidine dimer lesions by action of a single enzyme, photolyase, and visible light. Its presence has been demonstrated in a wide variety of organisms, ranging from simple prokaryotes to higher eukaryotes. We have isolated a human gene encoding a 66-kDa protein that shows clear overall homology to known bacterial photolyase genes. The human gene product is more similar to plant blue-light receptors within class I ph
Functional outcome after laparoscopic and open incisional hernia repair
Abstract:
Background:
The debate about the advantages of laparoscopic versus open incisional hernia repair is still ongoing. The primary outcomes of already published studies are mainly recurrence, pain and quality of life. Data on postoperative abdominal wall function after these corrections is still lacking. In this single center study muscle strength and transverse abdominal muscle thickness were analysed with regard to open and laparoscopic techniques.
Methods:
Thirty-five patients that underwent open and laparoscopic midline incisional hernia correction were included. Approximation of the rectus muscles was included in some open procedures but never in laparoscopic correction. Twelve healthy subjects without any abdominal operation functioned as a control group. Trunk flexion muscle strength of all operated patients and 12 healthy subjects was studied with the Biodex® isokinetic dynamometer and conventional abdominal muscle trainers for the rectus and oblique abdominal muscles. All patients underwent ultrasound examination of the abdominal wall for analysing transverse abdominal muscle thickness.
Results:
The mean torque/weight (%) for trunk flexion, measured with the Biodex®, was significantly higher in the control compared with the total patient group. Comparing trunk flexion with the Biodex® after either laparoscopic or open incisional hernia repair showed a trend in favour of the open group after adjusting for gender. The muscle strength measured by the conventional abdominal muscle trainers showed no differences between the operation groups. The transverse abdominal muscle thickness difference between rest and contraction was significantly higher in the open repair group.
Conclusions:
The isokinetic strength of trunk flexor muscles is reduced after an operation for incisional hernia. There is some evidence that open repair with approximation of the rectus abdominis muscles results in higher muscle strength of the rectus muscles and higher thickness differences between res
Multidrug- and extensively drug-resistant tuberculosis
We evaluated risk factors and treatment outcomes associated with multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) in Germany in 2004–2006. In 177 (4%) of 4,557 culture-positive TB cases, Mycobacterium tuberculosis isolates were identified as MDR TB; an additional 7 (0.15%) met criteria for XDR TB. Of these 184 patients, 148 (80%) were born in countries of the former Soviet Union. In patients with XDR TB, hospitalization was longer (mean ± SD 202 ± 130 vs. 123 ± 81 days; p = 0.015) and resistance to all first-line drugs was more frequent (36% vs. 86%; p = 0.013) than in patients with MDR TB. Seventy-four (40%) of these 184 patients received treatment with linezolid. Treatment success rates ranged from 59% for the entire cohort (59% for MDR TB and 57% for XDR TB) to 87% for those with a definitive outcome (n = 125; 89% for MDR TB and 80% for XDR TB). Extensive drug susceptibility testing and availability of second- and third-line drugs under inpatient management conditions permit relatively high treatment success rates in MDR- and XDR TB
Prototyping the Semantics of a DSL using ASF+SDF: Link to Formal Verification of DSL Models
A formal definition of the semantics of a domain-specific language (DSL) is a
key prerequisite for the verification of the correctness of models specified
using such a DSL and of transformations applied to these models. For this
reason, we implemented a prototype of the semantics of a DSL for the
specification of systems consisting of concurrent, communicating objects. Using
this prototype, models specified in the DSL can be transformed to labeled
transition systems (LTS). This approach of transforming models to LTSs allows
us to apply existing tools for visualization and verification to models with
little or no further effort. The prototype is implemented using the ASF+SDF
Meta-Environment, an IDE for the algebraic specification language ASF+SDF,
which offers efficient execution of the transformation as well as the ability
to read models and produce LTSs without any additional pre or post processing.Comment: In Proceedings AMMSE 2011, arXiv:1106.596
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