SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Class

64

More than 80 incidences of fish predation by semi-aquatic spiders - observed at the fringes of shallow freshwater streams, rivers, lakes, ponds, swamps, and fens - are reviewed. We provide evidence that fish predation by semi-aquatic spiders is geographically widespread, occurring on all continents except Antarctica. Fish predation by spiders appears to be more common in warmer areas between 40° S and 40° N. The fish captured by spiders, usually ranging from 2-6 cm in length, are among the most common fish taxa occurring in their respective geographic area (e.g., mosquitofish [Gambusia spp.] in the southeastern USA, fish of the order Characiformes in the Neotropics, killifish [Aphyosemion spp.] in Central and West Africa, as well as Australian native fish of the genera Galaxias, Melanotaenia, and Pseudomugil). Naturally occurring fish predation has been witnessed in more than a dozen spider species from the superfamily Lycosoidea (families Pisauridae, Trechaleidae, and Lycosidae), in two species of the superfamily Ctenoidea (family Ctenidae), and in one species of the superfamily Corinnoidea (family Liocranidae). The majority of reports on fish predation by spiders referred to pisaurid spiders of the genera Dolomedes and Nilus (>75% of observed incidences). There is laboratory evidence that spiders from several more families (e.g., the water spider Argyroneta aquatica [Cybaeidae], the intertidal spider Desis marina [Desidae], and the ‘swimming’ huntsman spider Heteropoda natans [Sparassidae]) predate fish as well. Our finding of such a large diversity of spider families being engaged in fish predation is novel. Semi-aquatic spiders captured fish whose body length exceeded the spiders' body length (the captured fish being, on average, 2.2 times as long as the spiders). Evidence suggests that fish prey might be an occasional prey item of substantial nutritional importance.

Concepts: Species, Predation, Order, Class, Spider, Wolf spider, Spider bite, Tarantula

42

Small-molecule synthesis usually relies on procedures that are highly customized for each target. A broadly applicable automated process could greatly increase the accessibility of this class of compounds to enable investigations of their practical potential. Here we report the synthesis of 14 distinct classes of small molecules using the same fully automated process. This was achieved by strategically expanding the scope of a building block-based synthesis platform to include even Csp3-rich polycyclic natural product frameworks and discovering a catch-and-release chromatographic purification protocol applicable to all of the corresponding intermediates. With thousands of compatible building blocks already commercially available, many small molecules are now accessible with this platform. More broadly, these findings illuminate an actionable roadmap to a more general and automated approach for small-molecule synthesis.

Concepts: Protein, Organic compound, Biochemistry, Organic chemistry, Class, Social class, Small molecule, Accessibility

27

Applying a fast over-segmentation algorithm to image and working on a region-based graph (instead of the pixelbased graph) is an efficient approach to reduce the computational complexity of graph-based image segmentation methods. Nevertheless, some undesirable effects may arise if the conventional cost functions such as Ncut, AverageCut and MinCut are employed for partitioning the region-based graph. This is because these cost functions are generally tailored to pixel-based graphs. In order to resolve this problem, we first introduce a new class of cost functions (containing Ncut and AverageCut) for graph partitioning whose corresponding suboptimal solution can be efficiently computed by solving a generalized eigenvalue problem. Then, among these cost functions, we propose one which considers the size of regions in the partitioning procedure. By simulation, the performance of the proposed cost function is quantitatively compared with that of the Ncut and AverageCut.

Concepts: Algorithm, Mathematics, Function, Graph theory, Problem solving, Computational complexity theory, Class, Marginal cost

26

An updated list of Issidae known from Vietnam is provided. Two new species, one from the genus Darwallia Gnezdilov, 2010, and another one from a new genus are described from the Hòn Bà massif in Central Vietnam. A key to species of the genus Darwallia is provided. Gelastyrella hainanensis Ran et Liang, 2006 is placed in synonymy under Thabena litaoensis Yang, 1994. This last taxon and the genus Gergithoides Schumacher, 1915 are recorded for the first time for Vietnamese fauna. New records in Vietnam are given for Tetrica philo Fennah, 1978 and Gergithus iguchii Matsumura, 1916. 

Concepts: Class, Scientific classification, International Code of Zoological Nomenclature, Zoological nomenclature, Botanical nomenclature, Chresonym, March 10, March 14

25

Attributes act as intermediate representations that enable parameter sharing between classes, a must when training data is scarce.We propose to view attribute-based image classification as a label-embedding problem: each class is embedded in the space of attribute vectors. We introduce a function that measures the compatibility between an image and a label embedding. The parameters of this function are learned on a training set of labeled samples to ensure that, given an image, the correct classes rank higher than the incorrect ones. Results on the Animals With Attributes and Caltech-UCSD-Birds datasets show that the proposed framework outperforms the standard Direct Attribute Prediction baseline in a zero-shot learning scenario. Label embedding enjoys a built-in ability to leverage alternative sources of information instead of or in addition to attributes, such as e.g. class hierarchies or textual descriptions. Moreover, label embedding encompasses the whole range of learning settings from zero-shot learning to regular learning with a large number of labeled examples.

Concepts: Skill, Machine learning, C, Parameter, Class, Subroutine, Currying, C++

24

A new type of surface modification of SOI-FET sensors with ultrathin sensor-probe transition layer and uncharged probes for highly specific detection of short RNA (saRNA) was suggested.

Concepts: Materials science, Surface engineering, Class, Surface modification

22

The aim of this study was to investigate differences between the virtually planned and clinically achieved implant positions in completely template-guided implantations as a function of the type of edentulous space, the residual natural dentition, and the surgical implementation.

Concepts: Surgery, Teeth, Dental implant, Object, C, Category theory, Class, Fortran

20

As we transition our undergraduate biology classrooms from traditional lectures to active learning, the dynamics among students become more important. These dynamics can be influenced by student social identities. One social identity that has been unexamined in the context of undergraduate biology is the spectrum of lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) identities. In this exploratory interview study, we probed the experiences and perceptions of seven students who identify as part of the LGBTQIA community. We found that students do not always experience the undergraduate biology classroom to be a welcoming or accepting place for their identities. In contrast to traditional lectures, active-learning classes increase the relevance of their LGBTQIA identities due to the increased interactions among students during group work. Finally, working with other students in active-learning classrooms can present challenges and opportunities for students considering their LGBTQIA identity. These findings indicate that these students' LGBTQIA identities are affecting their experience in the classroom and that there may be specific instructional practices that can mitigate some of the possible obstacles. We hope that this work can stimulate discussions about how to broadly make our active-learning biology classes more inclusive of this specific population of students.

Concepts: LGBT, Sexual orientation, Transgender, Class, Identity, Classroom, Gay, Queer theory

16

We present a quantum mechanical memristive Nb/Al/Al2O3/NbxOy/Au device which consists of an ultra-thin memristive layer (NbxOy) sandwiched between an Al2O3 tunnel barrier and a Schottky-like contact. A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm(2) and 2300 μm(2) were obtained, which indicates a non-filamentary based resistive switching mechanism. In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively. The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

Concepts: Electron, Electromagnetism, Electric current, Superconductivity, Class, Electrical resistance

14

Diagnosis of children with attention-deficit/hyperactivity disorder (ADHD) is increasing. The present study sought to identify characteristics and medication treatment patterns of children with ADHD and compare them by relative age in class, sex, ethnicity, family size, sibling order, and other socioeconomic status, as well as find trends in disparity of pharmacotherapy.

Concepts: Family, Attention-deficit hyperactivity disorder, Order, Stimulant, Taxonomic rank, Class, Sibling, Social status