175 research outputs found
ON THE SMARANDACHE FUNCTION AND SQUARE COMPLEMENTS
The main purpose of this paper is using the elementary method to study the mean value properties of the Smarandache function, and give an interesting asymptotic formula
On a problem of D.H. Lehmer over short intervals
AbstractLet p be an odd prime and a be an integer coprime to p. Denote by N(a,p) the number of pairs of integers b,c with bcā”aĀ (modĀ p), 1ā©½b,cā©½(pā1)2 and with b,c having different parity. The main purpose of this paper is to study the sum āa=1pā1(N(a,p)ā(pā1)8)2, and obtain a sharp asymptotic formula
On the order of the high-dimensional Cochrane sum and its mean value
AbstractThe main purpose of this paper is to study the high-dimensional Cochrane sum and give a sharp estimate of its order by using properties of hyper-Kloosterman sum and the mean value theorems of Dirichlet L-functions
Mining Word Boundaries in Speech as Naturally Annotated Word Segmentation Data
Inspired by early research on exploring naturally annotated data for Chinese
word segmentation (CWS), and also by recent research on integration of speech
and text processing, this work for the first time proposes to mine word
boundaries from parallel speech/text data. First we collect parallel
speech/text data from two Internet sources that are related with CWS data used
in our experiments. Then, we obtain character-level alignments and design
simple heuristic rules for determining word boundaries according to pause
duration between adjacent characters. Finally, we present an effective
complete-then-train strategy that can better utilize extra naturally annotated
data for model training. Experiments demonstrate our approach can significantly
boost CWS performance in both cross-domain and low-resource scenarios.Comment: latest versio
Surgery combined with radiotherapy for the treatment of solitary plasmacytoma of the rib: a case report and review of the literature
Drosophila Perlecan Regulates Intestinal Stem Cell Activity via Cell-Matrix Attachment
SummaryStem cells require specialized local microenvironments, termed niches, for normal retention, proliferation, and multipotency. Niches are composed of cells together with their associated extracellular matrix (ECM). Currently, the roles of ECM in regulating niche functions are poorly understood. Here, we demonstrate that Perlecan (Pcan), a highly conserved ECM component, controls intestinal stem cell (ISC) activities and ISC-ECM attachment in Drosophila adult posterior midgut. Loss of Pcan from ISCs, butĀ not other surrounding cells, causes ISCs to detach from underlying ECM, lose their identity, and fail to proliferate. These defectsĀ are not a result of a loss of epidermal growth factor receptor (EGFR) or Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling activity but partially depend on integrin signaling activity. We propose that Pcan secreted by ISCs confers niche properties to the adjacent ECM that is required for ISC maintenance of stem cell identity, activity, and anchorage to the niche
A tomato HD-Zip homeobox protein, LeHB-1, plays an important role in floral organogenesis and ripening
Ethylene is required for climacteric fruit ripening. Inhibition of ethylene biosynthesis genes, 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase, prevents or delays ripening, but it is not known how these genes are modulated during normal development. LeHB-1, a previously uncharacterized tomato homeobox protein, was shown by gel retardation assay to interact with the promoter of LeACO1, an ACC oxidase gene expressed during ripening. Inhibition of LeHB-1 mRNA accumulation in tomato fruit, using virus-induced gene silencing, greatly reduced LeACO1 mRNA levels, and inhibited ripening. Conversely, ectopic overexpression of LeHB-1 by viral delivery to developing flowers elsewhere on injected plants triggered altered floral organ morphology, including production of multiple flowers within one sepal whorl, fusion of sepals and petals, and conversion of sepals into carpel-like structures that grew into fruits and ripened. Our findings suggest that LeHB-1 is not only involved in the control of ripening but also plays a critical role in floral organogenesis
Mining Density Contrast Subgraphs
Dense subgraph discovery is a key primitive in many graph mining
applications, such as detecting communities in social networks and mining gene
correlation from biological data. Most studies on dense subgraph mining only
deal with one graph. However, in many applications, we have more than one graph
describing relations among a same group of entities. In this paper, given two
graphs sharing the same set of vertices, we investigate the problem of
detecting subgraphs that contrast the most with respect to density. We call
such subgraphs Density Contrast Subgraphs, or DCS in short. Two widely used
graph density measures, average degree and graph affinity, are considered. For
both density measures, mining DCS is equivalent to mining the densest subgraph
from a "difference" graph, which may have both positive and negative edge
weights. Due to the existence of negative edge weights, existing dense subgraph
detection algorithms cannot identify the subgraph we need. We prove the
computational hardness of mining DCS under the two graph density measures and
develop efficient algorithms to find DCS. We also conduct extensive experiments
on several real-world datasets to evaluate our algorithms. The experimental
results show that our algorithms are both effective and efficient.Comment: Full version of an ICDE'18 pape
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