387 research outputs found
Dental care programme for Hong Kong secondary school students : parents' choices and willingness to pay
published_or_final_versio
A Study of how coated paper\u27s roughness, gloss and absorptivity affect on side and print gloss
None provided
Finite Domain Bounds Consistency Revisited
A widely adopted approach to solving constraint satisfaction problems
combines systematic tree search with constraint propagation for pruning the
search space. Constraint propagation is performed by propagators implementing a
certain notion of consistency. Bounds consistency is the method of choice for
building propagators for arithmetic constraints and several global constraints
in the finite integer domain. However, there has been some confusion in the
definition of bounds consistency. In this paper we clarify the differences and
similarities among the three commonly used notions of bounds consistency.Comment: 12 page
Training Reinforcement Learning Agents and Humans With Difficulty-Conditioned Generators
We adapt Parameterized Environment Response Model (PERM), a method for
training both Reinforcement Learning (RL) Agents and human learners in
parameterized environments by directly modeling difficulty and ability.
Inspired by Item Response Theory (IRT), PERM aligns environment difficulty with
individual ability, creating a Zone of Proximal Development-based curriculum.
Remarkably, PERM operates without real-time RL updates and allows for offline
training, ensuring its adaptability across diverse students. We present a
two-stage training process that capitalizes on PERM's adaptability, and
demonstrate its effectiveness in training RL agents and humans in an empirical
study
Deep Spectroscopy of the Host Galaxy of a Tidal Disruption Flare in A1795
A likely tidal disruption of a star by the intermediate-mass black hole
(IMBH) of a dwarf galaxy was recently identified in association with Abell
1795. Without deep spectroscopy for this very faint object, however, the
possibility of a more massive background galaxy or even a disk-instability
flare from a weak AGN could not be dismissed. We have now obtained 8 hours of
Gemini spectroscopy which unambiguously demonstrate that the host galaxy is
indeed an extremely low-mass
galaxy in Abell 1795, comparable to the least-massive galaxies determined to
host IMBHs via other studies. We find that the spectrum is consistent with the
X-ray flare being due to a tidal disruption event rather than an AGN flare. We
also set improved limits on the black hole mass and infer a 15-year X-ray variability of a factor
of . The confirmation of this galaxy-black hole system provides a
glimpse into a population of galaxies that is otherwise difficult to study, due
to the galaxies' low masses and intrinsic faintness, but which may be important
contributors to the tidal disruption rate.Comment: 9 pages, 4 figures. Accepted by MNRA
An unusual S-adenosylmethionine synthetase gene from dinoflagellate is methylated
Background: S-Adenosylmethionine synthetase (AdoMetS) catalyzes the formation of S-Adenosylmethionine (AdoMet), the major methyl group donor in cells. AdoMet-mediated methylation of DNA is known to have regulatory effects on DNA transcription and chromosome structure. Transcription of environmental-responsive genes was demonstrated to be mediated via DNA methylation in dinoflagellates. Results: A full-length cDNA encoding AdoMetS was cloned from the dinoflagellate Crypthecodinium cohnii. Phylogenetic analysis suggests that the CcAdoMetS gene, is associated with the clade of higher plant orthrologues, and not to the clade of the animal orthrologues. Surprisingly, three extra stretches of residues ( 8 to 19 amino acids) were found on CcAdoMetS, when compared to other members of this usually conserved protein family. Modeled on the bacterial AdeMetS, two of the extra loops are located close to the methionine binding site. Despite this, the CcAdoMetS was able to rescue the corresponding mutant of budding yeast. Southern analysis, coupled with methylation-sensitive and insensitive enzyme digestion of C. cohnii genomic DNA, demonstrated that the AdoMetS gene is itself methylated. The increase in digestibility of methylation-sensitive enzymes on AdoMet synthetase gene observed following the addition of DNA methylation inhibitors L-ethionine and 5-azacytidine suggests the presence of cytosine methylation sites within CcAdoMetS gene. During the cell cycle, both the transcript and protein levels of CcAdoMetS peaked at the G1 phase. L- ethionine was able to delay the cell cycle at the entry of S phase. A cell cycle delay at the exit of G2/M phase was induced by 5-azacytidine. Conclusion: The present study demonstrates a major role of AdoMet-mediated DNA methylation in the regulation of cell proliferation and that the CcAdoMetS gene is itself methylated
A Comparison of Lex Bounds for Multiset Variables in Constraint Programming
Set and multiset variables in constraint programming have typically been
represented using subset bounds. However, this is a weak representation that
neglects potentially useful information about a set such as its cardinality.
For set variables, the length-lex (LL) representation successfully provides
information about the length (cardinality) and position in the lexicographic
ordering. For multiset variables, where elements can be repeated, we consider
richer representations that take into account additional information. We study
eight different representations in which we maintain bounds according to one of
the eight different orderings: length-(co)lex (LL/LC), variety-(co)lex (VL/VC),
length-variety-(co)lex (LVL/LVC), and variety-length-(co)lex (VLL/VLC)
orderings. These representations integrate together information about the
cardinality, variety (number of distinct elements in the multiset), and
position in some total ordering. Theoretical and empirical comparisons of
expressiveness and compactness of the eight representations suggest that
length-variety-(co)lex (LVL/LVC) and variety-length-(co)lex (VLL/VLC) usually
give tighter bounds after constraint propagation. We implement the eight
representations and evaluate them against the subset bounds representation with
cardinality and variety reasoning. Results demonstrate that they offer
significantly better pruning and runtime.Comment: 7 pages, Proceedings of the Twenty-Fifth AAAI Conference on
Artificial Intelligence (AAAI-11
Epigenetic Dysregulation in Laryngeal Squamous Cell Carcinoma
Laryngeal carcinoma is a common head and neck cancer with poor prognosis. Patients with laryngeal carcinoma usually present late leading to the reduced treatment efficacy and high rate of recurrence. Despite the advance in the use of molecular markers for monitoring human cancers in the past decades, there are still no reliable markers for use to screen laryngeal carcinoma and follow the patients after treatment. Epigenetics emerged as an important field in understanding the biology of the human malignancies. Epigenetic alterations refer to the dysregulation of gene, which do not involve the alterations of the DNA sequence. Major epigenetic changes including methylation imbalance, histone modification, and small RNA dysregulation could play a role in the development of human malignancies. Global epigenetic change is now regarded as a molecular signature of cancer. The characteristics and behavior of a cancer could be predicted based on the specific epigenetic pattern. We here provide a review on the understanding of epigenetic dysregulation in laryngeal carcinoma. Further knowledge on the initiation and progression of laryngeal carcinoma at epigenetic level could promote the translation of the knowledge to clinical use
- …