686 research outputs found
Subresultants in multiple roots: an extremal case
We provide explicit formulae for the coefficients of the order-d polynomial
subresultant of (x-\alpha)^m and (x-\beta)^n with respect to the set of
Bernstein polynomials \{(x-\alpha)^j(x-\beta)^{d-j}, \, 0\le j\le d\}. They are
given by hypergeometric expressions arising from determinants of binomial
Hankel matrices.Comment: 18 pages, uses elsart. Revised version accepted for publication at
Linear Algebra and its Application
On the String Consensus Problem and the Manhattan Sequence Consensus Problem
In the Manhattan Sequence Consensus problem (MSC problem) we are given
integer sequences, each of length , and we are to find an integer sequence
of length (called a consensus sequence), such that the maximum
Manhattan distance of from each of the input sequences is minimized. For
binary sequences Manhattan distance coincides with Hamming distance, hence in
this case the string consensus problem (also called string center problem or
closest string problem) is a special case of MSC. Our main result is a
practically efficient -time algorithm solving MSC for sequences.
Practicality of our algorithms has been verified experimentally. It improves
upon the quadratic algorithm by Amir et al.\ (SPIRE 2012) for string consensus
problem for binary strings. Similarly as in Amir's algorithm we use a
column-based framework. We replace the implied general integer linear
programming by its easy special cases, due to combinatorial properties of the
MSC for . We also show that for a general parameter any instance
can be reduced in linear time to a kernel of size , so the problem is
fixed-parameter tractable. Nevertheless, for this is still too large
for any naive solution to be feasible in practice.Comment: accepted to SPIRE 201
Electrical and quench performance of the first MICE coupling coil
The first MICE Coupling Coil has been tested in a conduction-cooled environment in the new Solenoid Test Facility at Fermilab. We present an overview of the power and quench protection scheme, and report on the electrical and quench performance results obtained during cold power tests of the magnet
Early respiratory diagnosis: benefits of enhanced lung function assessment.
INTRODUCTION: The National Health Service for England Long Term Plan identifies respiratory disease as one of its priority workstreams. To assist with earlier and more accurate diagnosis of lung disease they recommend improvement in delivery of quality-assured spirometry. However, there is a likelihood that patients will present with abnormal gas exchange when spirometry results are normal and therefore there will be a proportion of patients whose time to diagnosis is still protracted. We wished to determine the incidence rate of this occurring within our Trust. METHODS: A retrospective review of all patients attending the lung function laboratory for their first pulmonary function assessment from June 2006 to December 2020 was undertaken. Forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) >-1.64 standardised residual (SR) was used to confirm no obstructive lung function abnormality and FVC >-1.64 SR to confirm no suggestion of a restrictive lung function abnormality. Lung gas transfer for carbon monoxide (TLCO) and transfer coefficient of the lung for carbon monoxide (KCO) <-1.64 SR confirmed the presence of a gas exchange abnormality. Spirometry and gas transfer reference values generated by the Global Lung Initiative were used to determine normality. RESULTS: Of 12 835 eligible first visits with normal FEV1/FVC and FVC, 4856 (37.8%) were identified as having an abnormally low TLCO and 3302 (25.7%) presenting with an abnormally low KCO. Of 3494 with FEV1/FVC SR <-1.64, 3316 also had a ratio of <0.70, meaning 178 (5%) of patients in this cohort would have been misclassified as having obstructive lung disease using the 0.70 cut-off recommended by the Global Initiative for Chronic Obstructive Lung Disease for diagnosing obstructive lung disease. DISCUSSION: In conclusion, to assist with ensuring more accurate and timely diagnosis of lung disease and enhance patients' diagnostic pathway, we recommend the performance of lung gas transfer measurements alongside spirometry in all healthcare settings. To assess and monitor gas transfer at the earliest opportunity we recommend this is implemented into new models being developed within community hubs. This will increase the identification of lung function abnormalities and provide patients with a definitive diagnosis earlier
The Adoption of Digital Games Among Older Adults
The revolution of technology brings many benefits towards diverse population. Digital game is one of the digital technologies that has potential to facilitate older adults’ daily routine. However, some of them faces challenges to adopt the usage of digital games in their daily lives, one of which is that most commercial games are not suitable for older people. This paper discusses the investigation into the challenges associated with the older adults’ adoption of digital games, their interaction, and experiences with digital games and specifically explores the andragogical perspectives, and game design attributes. A set of questionnaires consisted of open-ended and close-ended questions were distributed, targeting the older adults across Malaysia, using online and non-probability sampling technique. 81 respondents were recruited, and 56 respondents (n=56) were eligible in this study. Four participants were recruited for informal interview session. The analysis of the results indicates that the older adults’ perception of digital games and game design aspects are the major factors influencing their digital game adoption. Game designs are important to attract many older adults to experience and interact with digital games
Thiothymidine combined with UVA as a potential novel therapy for bladder cancer
BACKGROUND: Thiothymidine (S4TdR) can be incorporated into DNA and sensitise cells to DNA damage and cell death following exposure to UVA light. Studies were performed to determine if the combination of S4TdR and UVA could be an effective treatmentfor bladder cancer.
METHODS: Uptake and incorporation of S4TdR was determined in rat and human bladder tumour cell lines. Measures of DNA crosslinking and apoptosis were also performed. In vivo activity of the combination of S4TdR and UVA was investigated in an orthotopic model of bladder cancer in rats.
RESULTS: Thiothymidine (200 uM) replaced up to 0.63% of thymidine in rat and tumour bladder cancer cells. The combination of S4TdR (10–200 uM) and UVA (1–5 kJm-2) caused apoptosis and cell death at doses that were not toxic alone. Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S4TdR into DNA (up to 20-fold at IC5) and further sensitised cells to UVA. Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein. Intravenous administration of S4TdR, in combination with UVA delivered directly to the bladder, resulted in an antitumour effect in three of five animals treated.
CONCLUSION: These data indicate that the combination of S4TdR and UVA has potential as a treatment for bladder cancer, and give some insight into the mechanism of action. Further work is necessary to optimise the delivery of the two components
Activation of superior colliculi in humans during visual exploration
<p>Abstract</p> <p>Background</p> <p>Visual, oculomotor, and – recently – cognitive functions of the superior colliculi (SC) have been documented in detail in non-human primates in the past. Evidence for corresponding functions of the SC in humans is still rare. We examined activity changes in the human tectum and the lateral geniculate nuclei (LGN) in a visual search task using functional magnetic resonance imaging (fMRI) and anatomically defined regions of interest (ROI). Healthy subjects conducted a free visual search task and two voluntary eye movement tasks with and without irrelevant visual distracters. Blood oxygen level dependent (BOLD) signals in the SC were compared to activity in the inferior colliculi (IC) and LGN.</p> <p>Results</p> <p>Neural activity increased during free exploration only in the SC in comparison to both control tasks. Saccade frequency did not exert a significant effect on BOLD signal changes. No corresponding differences between experimental tasks were found in the IC or the LGN. However, while the IC revealed no signal increase from the baseline, BOLD signal changes at the LGN were consistently positive in all experimental conditions.</p> <p>Conclusion</p> <p>Our data demonstrate the involvement of the SC in a visual search task. In contrast to the results of previous studies, signal changes could not be seen to be driven by either visual stimulation or oculomotor control on their own. Further, we can exclude the influence of any nearby neural structures (e.g. pulvinar, tegmentum) or of typical artefacts at the brainstem on the observed signal changes at the SC. Corresponding to findings in non-human primates, our data support a dependency of SC activity on functions beyond oculomotor control and visual processing.</p
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