Spotting Trees with Few Leaves

We show two results related to the Hamiltonicity and $k$-Path algorithms in undirected graphs by Bj\"orklund [FOCS'10], and Bj\"orklund et al., [arXiv'10]. First, we demonstrate that the technique used can be generalized to finding some $k$-vertex tree with $l$ leaves in an $n$-vertex undirected graph in $O^*(1.657^k2^{l/2})$ time. It can be applied as a subroutine to solve the $k$-Internal Spanning Tree ($k$-IST) problem in $O^*(\min(3.455^k, 1.946^n))$ time using polynomial space, improving upon previous algorithms for this problem. In particular, for the first time we break the natural barrier of $O^*(2^n)$. Second, we show that the iterated random bipartition employed by the algorithm can be improved whenever the host graph admits a vertex coloring with few colors; it can be an ordinary proper vertex coloring, a fractional vertex coloring, or a vector coloring. In effect, we show improved bounds for $k$-Path and Hamiltonicity in any graph of maximum degree $\Delta=4,\ldots,12$ or with vector chromatic number at most 8

A survey of cherry leaf roll virus in intensively managed grafted english (Persian) walnut trees in Italy

Blackline disease, caused by Cherry leaf roll virus (CLRV), is considered a serious threat limiting English walnut (Juglans regia) production in Italy and the EU if walnut species other than J. regia e.g. \u2018Paradox\u2019 hybrid (J. regia 7 J. hindsii), French hybrid (J. regia 7 J. major or J. regia 7 J. nigra) or northern California black walnut (J. hindsii) are used as the rootstock. The virus transmissibility by pollen as well as latent infections can result in the spread of CLRVcontaminated propagative material, which is a major means of the virus dispersal by human activities. In 2014 and 2015 to ascertain the presence and the distribution of blackline symptoms in commercial orchards and to provide a description of the symptomatology, visual inspections and double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) analyses were carried out on 1,684 walnut trees in four different intensively managed grafted English walnut orchards in northeast Italy (Veneto Region). Trees with clear blackline symptoms at the scion-rootstock junction, often associated with general decline of the plant, were found only in one commercial orchard in northeast Italy on trees older than ten years of cvs. \u2018Tulare\u2019 and \u2018Chandler\u2019, grafted onto \u2018Paradox\u2019 rootstock. To our knowledge this is the first report of CLRV (blackline) decline and death in a commercial walnut orchard in Italy

Object Proposals for Text Extraction in the Wild

Object Proposals is a recent computer vision technique receiving increasing interest from the research community. Its main objective is to generate a relatively small set of bounding box proposals that are most likely to contain objects of interest. The use of Object Proposals techniques in the scene text understanding field is innovative. Motivated by the success of powerful while expensive techniques to recognize words in a holistic way, Object Proposals techniques emerge as an alternative to the traditional text detectors. In this paper we study to what extent the existing generic Object Proposals methods may be useful for scene text understanding. Also, we propose a new Object Proposals algorithm that is specifically designed for text and compare it with other generic methods in the state of the art. Experiments show that our proposal is superior in its ability of producing good quality word proposals in an efficient way. The source code of our method is made publicly available.Comment: 13th International Conference on Document Analysis and Recognition (ICDAR 2015

Ornamental Evergreens

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