Hyperspectral Probing of Exciton dynamics and Multiplication in PbSe Nanocrystals

Height time hyperspectral near IR probing providing broad-band coverage is employed on PbSe nanocrystals, uncovering spectral evolution following high energy photo-excitation due to hot exciton relaxation and recombination. Separation of single, double and triple exciton state contributions to these spectra is demonstrated, and the mechanisms underlying the course of spectral evolution are investigated. In addition no sign of MEG was detected in this sample up to a photon energy 3.7 times that of the band gap

An Essay concerning machine understanding

Artificial intelligence systems exhibit many useful capabilities, but they appear to lack understanding. This essay describes how we could go about constructing a machine capable of understanding. As John Locke (1689) pointed out words are signs for ideas, which we can paraphrase as thoughts and concepts. To understand a word is to know and be able to work with the underlying concepts for which it is an indicator. Understanding between a speaker and a listener occurs when the speaker casts his or her concepts into words and the listener recovers approximately those same concepts. Current models rely on the listener to construct any potential meaning. The diminution of behaviorism as a psychological paradigm and the rise of cognitivism provide examples of many experimental methods that can be used to determine whether and to what extent a machine might understand and to make suggestions about how that understanding might be instantiated

A framework for evaluating automatic indexing or classification in the context of retrieval

Tools for automatic subject assignment help deal with scale and sustainability in creating and enriching metadata, establishing more connections across and between resources and enhancing consistency. While some software vendors and experimental researchers claim the tools can replace manual subject indexing, hard scientific evidence of their performance in operating information environments is scarce. A major reason for this is that research is usually conducted in laboratory conditions, excluding the complexities of real-life systems and situations. The paper reviews and discusses issues with existing evaluation approaches such as problems of aboutness and relevance assessments, implying the need to use more than a single “gold standard” method when evaluating indexing and retrieval and proposes a comprehensive evaluation framework. The framework is informed by a systematic review of the literature on indexing, classification and approaches: evaluating indexing quality directly through assessment by an evaluator or through comparison with a gold standard; evaluating the quality of computer-assisted indexing directly in the context of an indexing workflow, and evaluating indexing quality indirectly through analyzing retrieval performance

Layered control architectures in robots and vertebrates

We revieiv recent research in robotics, neuroscience, evolutionary neurobiology, and ethology with the aim of highlighting some points of agreement and convergence. Specifically, we com pare Brooks' (1986) subsumption architecture for robot control with research in neuroscience demonstrating layered control systems in vertebrate brains, and with research in ethology that emphasizes the decomposition of control into multiple, intertwined behavior systems. From this perspective we then describe interesting parallels between the subsumption architecture and the natural layered behavior system that determines defense reactions in the rat. We then consider the action selection problem for robots and vertebrates and argue that, in addition to subsumption- like conflict resolution mechanisms, the vertebrate nervous system employs specialized selection mechanisms located in a group of central brain structures termed the basal ganglia. We suggest that similar specialized switching mechanisms might be employed in layered robot control archi tectures to provide effective and flexible action selection

Screening Procedure for Hemihypertrophy: Preliminary Results of International Multicenter Prospective Study

Introduction: Isolated or congenital hemihypertrophy is a rare disorder characterized by asymmetric overgrowth of one side of the body. This article describes the protocol and preliminary results of a lateral body asymmetry (hemihypertrophy) screening procedure performed in healthy adolescents in a multicenter study. The reported incidence of hemihypertrophy varies between different publications and standardized protocols are needed to improve research in this area.Methods: Our screening program is taking place in Australia, Israel, Mexico, Ukraine and USA. Procedure includes two steps:  (1) “three measurements – three questions” screening, or assessment of face, palms, and shins; (2) in-depth assessment of selected cases in order to exclude localized, lesional, and syndrome-related cases as well as body asymmetry within normative range and to select suspected cases of isolated hemihypertrophy. This step includes measurements of various anatomical regions and a detailed questionnaire.Results: At this stage, the screening procedure is completed and the selected participants are advised to refer to medical institutions for further clinical and genetic follow up to exclude possible tumors and other accompanying disorders.Conclusion: We present an easy-to-use selection tool to identify children with suspected IH, which results in the selection of the risk group that may benefit from referral to a pediatrician and a clinical geneticist

Screening Procedure for Hemihypertrophy: Preliminary Results of International Multicenter Prospective Study

Introduction: Isolated or congenital hemihypertrophy is a rare disorder characterized by asymmetric overgrowth of one side of the body. This article describes the protocol and preliminary results of a lateral body asymmetry (hemihypertrophy) screening procedure performed in healthy adolescents in a multicenter study. The reported incidence of hemihypertrophy varies between different publications and standardized protocols are needed to improve research in this area. Methods: Our screening program is taking place in Australia, Israel, Mexico, Ukraine and USA. Procedure includes two steps:  (1) “three measurements – three questions” screening, or assessment of face, palms, and shins; (2) in-depth assessment of selected cases in order to exclude localized, lesional, and syndrome-related cases as well as body asymmetry within normative range and to select suspected cases of isolated hemihypertrophy. This step includes measurements of various anatomical regions and a detailed questionnaire. Results: At this stage, the screening procedure is completed and the selected participants are advised to refer to medical institutions for further clinical and genetic follow up to exclude possible tumors and other accompanying disorders. Conclusion: We present an easy-to-use selection tool to identify children with suspected IH, which results in the selection of the risk group that may benefit from referral to a pediatrician and a clinical geneticist

Why Do Dolphins Carry Sponges?

Tool use is rare in wild animals, but of widespread interest because of its relationship to animal cognition, social learning and culture. Despite such attention, quantifying the costs and benefits of tool use has been difficult, largely because if tool use occurs, all population members typically exhibit the behavior. In Shark Bay, Australia, only a subset of the bottlenose dolphin population uses marine sponges as tools, providing an opportunity to assess both proximate and ultimate costs and benefits and document patterns of transmission. We compared sponge-carrying (sponger) females to non-sponge-carrying (non-sponger) females and show that spongers were more solitary, spent more time in deep water channel habitats, dived for longer durations, and devoted more time to foraging than non-spongers; and, even with these potential proximate costs, calving success of sponger females was not significantly different from non-spongers. We also show a clear female-bias in the ontogeny of sponging. With a solitary lifestyle, specialization, and high foraging demands, spongers used tools more than any non-human animal. We suggest that the ecological, social, and developmental mechanisms involved likely (1) help explain the high intrapopulation variation in female behaviour, (2) indicate tradeoffs (e.g., time allocation) between ecological and social factors and, (3) constrain the spread of this innovation to primarily vertical transmission