Prevalence of +405G>C,−1154G>A Vascular Endothelial Growth Factor Polymorphism in Breast Cancer     

Rani James  G. Ramesh  Lakshmi Krishnamoorthy  Rahul Bhagat  Shilpa Chadaga  Vijayalaxmi Deshmane  Girija Ramaswamy 《Indian journal of clinical biochemistry : IJCB》2014,29(1):21-28

Vascular endothelial growth factor (VEGF) plays an important role in the development of Breast Cancer. The aim of this study was to investigate the association of polymorphisms in the VEGF gene on prognosis of Breast Cancer patients. This study comprised 200 patients with histologically confirmed cases of Breast cancer and 200 controls. Genotyping of the VEGF gene polymorphisms at +405G>C,−1154G>A, were performed by PCR-RFLP analysis. Preoperative plasma VEGF levels were determined by ELISA. Amongst both cases and controls, the genotypic distribution of the individual SNPs were all in Hardy–Weinberg equilibrium. Mean VEGF level was significantly elevated in cases compared to controls (t = 8.248; P < 0.001). No significant association was found between +405G>C,−1154G>A VEGF polymorphism and Breast Cancer. Logistic regression analysis revealed that 405GG & 1154GG were associated with higher levels of VEGF.  相似文献   

s-grams: Defining generalized n-grams for information retrieval     

Anni Järvelin  Antti Järvelin  Kalervo Järvelin 《Information processing & management》2007

n-grams have been used widely and successfully for approximate string matching in many areas. s-grams have been introduced recently as an n-gram based matching technique, where di-grams are formed of both adjacent and non-adjacent characters. s-grams have proved successful in approximate string matching across language boundaries in Information Retrieval (IR). s-grams however lack precise definitions. Also their similarity comparison lacks precise definition. In this paper, we give precise definitions for both. Our definitions are developed in a bottom-up manner, only assuming character strings and elementary mathematical concepts. Extending established practices, we provide novel definitions of s-gram profiles and the L₁ distance metric for them. This is a stronger string proximity measure than the popular Jaccard similarity measure because Jaccard is insensitive to the counts of each n-gram in the strings to be compared. However, due to the popularity of Jaccard in IR experiments, we define the reduction of s-gram profiles to binary profiles in order to precisely define the (extended) Jaccard similarity function for s-grams. We also show that n-gram similarity/distance computations are special cases of our generalized definitions.  相似文献   

RelRank: A relevance-based author ranking algorithm for individual publication venues     

《Information processing & management》2023,60(1):103156

Hiring appropriate editors, chairs and committee members for academic journals and conferences is challenging. It requires a targeted search for high profile scholars who are active in the field as well as in the publication venue. Many author-level metrics have been employed for this task, such as the h-index, PageRank and their variants. However, these metrics are global measures which evaluate authors’ productivity and impact without differentiating the publication venues. From the perspective of a venue, it is also important to have a localised metric which can specifically indicate the significance of academic authors for the particular venue. In this paper, we propose a relevance-based author ranking algorithm to measure the significance of authors to individual venues. Specifically, we develop a co-authorship network considering the author-venue relationship which integrates the statistical relevance of authors to individual venues. The RelRank, an improved PageRank algorithm embedding author relevance, is then proposed to rank authors for each venue. Extensive experiments are carried out to analyse the proposed RelRank in comparison with classic author-level metrics on three datasets of different research domains. We also evaluate the effectiveness of the RelRank and comparison metrics in recommending editorial boards of three venues using test data. Results demonstrate that the RelRank is able to identify not only the high profile scholars but also those who are particularly significant for individual venues.  相似文献   

A generalized cluster centroid based classifier for text categorization     

Guansong Pang  Shengyi Jiang 《Information processing & management》2013

In this paper, a Generalized Cluster Centroid based Classifier (GCCC) and its variants for text categorization are proposed by utilizing a clustering algorithm to integrate two well-known classifiers, i.e., the K-nearest-neighbor (KNN) classifier and the Rocchio classifier. KNN, a lazy learning method, suffers from inefficiency in online categorization while achieving remarkable effectiveness. Rocchio, which has efficient categorization performance, fails to obtain an expressive categorization model due to its inherent linear separability assumption. Our proposed method mainly focuses on two points: one point is that we use a clustering algorithm to strengthen the expressiveness of the Rocchio model; another one is that we employ the improved Rocchio model to speed up the categorization process of KNN. Extensive experiments conducted on both English and Chinese corpora show that GCCC and its variants have better categorization ability than some state-of-the-art classifiers, i.e., Rocchio, KNN and Support Vector Machine (SVM).  相似文献   

Positive-real systems under lossless transformations: Invariants and reduced order models     

A. Buscarino  L. Fortuna  M. Frasca  M.G. Xibilia 《Journal of The Franklin Institute》2017,354(11):4273-4288

In this paper, positive-real systems under lossless positive-real transformations are investigated. Let G(s) be the transfer function matrix of a continuous-time positive-real system of order n and F(s) a lossless transfer function of order n_F. We prove here that the lossless positive-real transformed system, i.e. G(F(s)), is also positive-real. Furthermore, the stochastic balanced representation of positive-real systems under lossless positive-real transformations is considered. In particular, it is proved that the positive-real characteristic values π_j of G(F(s)) are the same of G(s) each with multiplicity n_F, independently from the choice of F(s). This property is exploited in the design of reduced order models based on stochastic balancing. Finally, the proposed technique is a passivity preserving model order reduction method, since it is proven that the reduced order model of G(F(s)) is still positive-real. An error bound for truncation related to the invariants π_j is also derived.  相似文献   

Growth dynamics of citations of cumulative papers of individual authors according to progressive nucleation mechanism: Concept of citation acceleration     

Keshra Sangwal 《Information processing & management》2013

Using data generated by progressive nucleation mechanism on the cumulative fraction of citations of individual papers published successively by a hypothetical author, an expression for the time dependence of the cumulative number L_sum(t) of citations of progressively published papers is proposed. It was found that, for all nonzero values of constant publication rate ΔN, the cumulative citations L_sum(t) of the cumulative N papers published by an author in his/her entire publication career spanning over T years may be represented in distinct regions: (1) in the region 0 < t < Θ₀ (where Θ₀ ≈ T/3), L_sum(t) slowly increases proportionally to the square of the citation time t, and (2) in the region t > Θ₀, L_sum(t) approaches a constant L_sum(max) at T. In the former region, the time dependence of L_sum(t) of an author is associated with three parameters, viz. the citability parameter λ₀, the publication rate ΔN and his/her publication career t. Based on the predicted dependence of L_sum(t) on t, a useful scientometric age-independent measure, defined as citation acceleration a = L_sum(t)/t², is suggested to analyze and compare the scientific activities of different authors. Confrontation of the time dependence of cumulative number L_sum(t) of citations of papers with the theoretical equation reveals one or more citation periods during the publication careers of different authors.  相似文献   

H_∞ filtering for linear neutral systems with mixed time-varying delays and nonlinear perturbations     

Dan Zhang  Li Yu 《Journal of The Franklin Institute》2010,347(7):1374-1390

In this paper, the problem of H_∞ filtering for neutral systems with mixed time-varying delays and nonlinear perturbations is investigated. Some new delay-dependent sufficient conditions are presented to ensure that the filtering error system is asymptotically stable with a prescribed level of H_∞ noise attenuation. In addition, the design procedures for the existence of such filter are presented in terms of a set of linear matrix inequalities (LMIs). Slack variables and convex combination technique are adopted to reduce the conservatism of obtained results. Finally, three numerical examples are given to illustrate the effectiveness of the proposed method.  相似文献   

Equivalent formulations of the Müntz-Szász completeness condition for systems of complex exponentials     

Luc Knockaert 《Journal of The Franklin Institute》2002,339(1):103-109

New results pertaining to the completeness of a system of complex exponentials in L_p spaces are presented. It is shown that the well-known Müntz-Szász condition can be interpreted in terms of an equivalence relation, thereby proving that the standard Müntz-Szász formulation is equivalent with certain alternative formulations.  相似文献   

Methods to account for citation inflation in research evaluation     

《Research Policy》2019,48(7):1855-1865

Quantitative research evaluation requires measures that are transparent, relatively simple, and free of disciplinary and temporal bias. We document and provide a solution to a hitherto unaddressed temporal bias – citation inflation – which arises from the basic fact that scientific publication is steadily growing at roughly 4% per year. Moreover, because the total production of citations grows by a factor of 2 every 12 years, this means that the real value of a citation depends on when it was produced. Consequently, failing to convert nominal citation values into real citation values produces significant mis-measurement of scientific impact. To address this problem, we develop a citation deflator method, outline the steps to generalize and implement it using the Web of Science portal, and analyze a large set of researchers from biology and physics to demonstrate how two common evaluation metrics – total citations and h-index – can differ by a remarkable amount depending on whether the underlying citation counts are deflated or not. In particular, our results show that the scientific impact of prior generations is likely to be significantly underestimated when citations are not deflated, often by 100% or more of the nominal value. Thus, our study points to the need for a systemic overhaul of the counting methods used evaluating citation impact – especially in the case of researchers, journals, and institutions – which can span several decades and thus several doubling periods.  相似文献   

Exposed facet-controlled N2 electroreduction on distinct Pt3Fe nanostructures of nanocubes,nanorods and nanowires     

Wu Tong  Bolong Huang  Pengtang Wang  Qi Shao  Xiaoqing Huang 《国家科学评论(英文版)》2021,8(1)

Understanding the correlation between exposed surfaces and performances of controlled nanocatalysts can aid effective strategies to enhance electrocatalysis, but this is as yet unexplored for the nitrogen reduction reaction (NRR). Here, we first report controlled synthesis of well-defined Pt₃Fe nanocrystals with tunable morphologies (nanocube, nanorod and nanowire) as ideal model electrocatalysts for investigating the NRR on different exposed facets. The detailed electrocatalytic studies reveal that the Pt₃Fe nanocrystals exhibit shape-dependent NRR electrocatalysis. The optimized Pt₃Fe nanowires bounded with high-index facets exhibit excellent selectivity (no N₂H₄ is detected), high activity with NH₃ yield of 18.3 μg h⁻¹ mg⁻¹_cat (0.52 μg h⁻¹ cm⁻²_ECSA; ECSA: electrochemical active surface area) and Faraday efficiency of 7.3% at −0.05 V versus reversible hydrogen electrode, outperforming the {200} facet-enclosed Pt₃Fe nanocubes and {111} facet-enclosed Pt₃Fe nanorods. They also show good stability with negligible activity change after five cycles. Density functional theory calculations reveal that, with high-indexed facet engineering, the Fe-3d band is an efficient d-d coupling correlation center for boosting the Pt 5d-electronic exchange and transfer activities towards the NRR.  相似文献   

Relations between the shape of a size-frequency distribution and the shape of a rank-frequency distribution     

L. Egghe  L. Waltman 《Information processing & management》2011

We study the dependence of the shape of the rank-frequency distribution g on the shape of the size-frequency distribution f and vice versa. We show mathematically that g is convexly decreasing if and only if f is monotonically decreasing and that g has an S-shape (i.e., g is first convexly decreasing and then concavely decreasing) if and only if f is first increasing and then decreasing.  相似文献