Invariance principle for Mott variable range hopping and other walks on point processes

We consider a random walk on a homogeneous Poisson point process with energy marks. The jump rates decay exponentially in the A-power of the jump length and depend on the energy marks via a Boltzmann--like factor. The case A=1 corresponds to the phonon-induced Mott variable range hopping in disordered solids in the regime of strong Anderson localization. We prove that for almost every realization of the marked process, the diffusively rescaled random walk, with arbitrary start point, converges to a Brownian motion whose diffusion matrix is positive definite, and independent of the environment. Finally, we extend the above result to other point processes including diluted lattices.Comment: 47 pages, minor corrections, submitte

A Successful Broad-band Survey for Giant Lya Nebulae I: Survey Design and Candidate Selection

Giant Lya nebulae (or Lya "blobs") are likely sites of ongoing massive galaxy formation, but the rarity of these powerful sources has made it difficult to form a coherent picture of their properties, ionization mechanisms, and space density. Systematic narrow-band Lya nebula surveys are ongoing, but the small redshift range covered and the observational expense limit the comoving volume that can be probed by even the largest of these surveys and pose a significant problem when searching for such rare sources. We have developed a systematic search technique designed to find large Lya nebulae at 2<z<3 within deep broad-band imaging and have carried out a survey of the 9.4 square degree NOAO Deep Wide-Field Survey (NDWFS) Bootes field. With a total survey comoving volume of ~10^8 h^-3_70 Mpc^3, this is the largest volume survey for Lya nebulae ever undertaken. In this first paper in the series, we present the details of the survey design and a systematically-selected sample of 79 candidates, which includes one previously discovered Lya nebula.Comment: Accepted to ApJ after minor revision; 25 pages in emulateapj format; 18 figures, 3 table

Connectionist simulation of attitude learning: Asymmetries in the acquisition of positive and negative evaluations

Connectionist computer simulation was employed to explore the notion that, if attitudes guide approach and avoidance behaviors, false negative beliefs are likely to remain uncorrected for longer than false positive beliefs. In Study 1, the authors trained a three-layer neural network to discriminate "good" and "bad" inputs distributed across a two-dimensional space. "Full feedback" training, whereby connection weights were modified to reduce error after every trial, resulted in perfect discrimination. "Contingent feedback," whereby connection weights were only updated following outputs representing approach behavior, led to several false negative errors (good inputs misclassified as bad). In Study 2, the network was redesigned to distinguish a system for learning evaluations from a mechanism for selecting actions. Biasing action selection toward approach eliminated the asymmetry between learning of good and bad inputs under contingent feedback. Implications for various attitudinal phenomena and biases in social cognition are discussed

The 1996 U.S. Purse Seine Fishery for Tropical Tunas in the Central-Western Pacific Ocean

The U.S. tropical tuna purse seine fleet has fished the central-western Pacific Ocean under the South Pacific Tuna Treaty since 1988. The 1996 fishery was the poorest since the start ofthe Treaty. Fishing effort declined due to the financial collapse of a large fishing enterprise. Catches reached record lows for yellowfin tuna, Thunnus albacares, and skipjack tuna, Katsuwonus pelamis, and continued a declining trend that started in 1995. Catch rates also decreased to the lowest levels since 1991. Whether this declining trend in catch rates is due to reduced availability of fish caused by cyclic ocean environmental changes affecting vulnerability or to reduced abundance from excessive fishing pressure is not yet known and needs to be assessed

Analysing the limitations of deep learning for developmental robotics

Deep learning is a powerful approach to machine learning however its inherent disadvantages leave much to be desired in the pursuit of the perfect learning machine. This paper outlines the multiple disadvantages of deep learning and offers a view into the implications to solving these problems and how this would affect the state of the art not only in developmental learning but also in real world applications

Adaptive cancelation of self-generated sensory signals in a whisking robot

Sensory signals are often caused by one's own active movements. This raises a problem of discriminating between self-generated sensory signals and signals generated by the external world. Such discrimination is of general importance for robotic systems, where operational robustness is dependent on the correct interpretation of sensory signals. Here, we investigate this problem in the context of a whiskered robot. The whisker sensory signal comprises two components: one due to contact with an object (externally generated) and another due to active movement of the whisker (self-generated). We propose a solution to this discrimination problem based on adaptive noise cancelation, where the robot learns to predict the sensory consequences of its own movements using an adaptive filter. The filter inputs (copy of motor commands) are transformed by Laguerre functions instead of the often-used tapped-delay line, which reduces model order and, therefore, computational complexity. Results from a contact-detection task demonstrate that false positives are significantly reduced using the proposed scheme

Preregistration house officers in general practice: review of evidence

OBJECTIVES: To examine the strengths and weaknesses of the national and local schemes for preregistration house officers to spend four months in general practice, to identify any added value from such placements, and to examine the impact on career choices. DESIGN: Review of all studies that reported on placements of preregistration house officers in general practice. SETTING: 19 accounts of preregistration house officers’ experience in general practice, ranging from single case reports to a national evaluation study, in a variety of locations in Scotland and England. PARTICIPANTS: Views of 180 preregistration house officers, 45 general practitioner trainers, and 105 consultant trainers. MAIN OUTCOME MEASURES: Main findings or themes weighted according to number of studies reporting them and weighted for sample size. RESULTS: The studies were unanimous about the educational benefits of the placements. The additional learning included communication skills, social and psychological factors in illness, patient centred consultations, broadening of knowledge base, and dealing with uncertainty about diagnosis and referral. CONCLUSIONS: Despite the reported benefits and recommendations of the scheme, it is not expanding. General practitioner trainers reported additional supervision that was unremunerated. The reforms of the senior house officer grade may resolve this problem by offering the placements to senior house officers, who require less supervision

Comparison of Continuous Versus Interrupted Chest Compressions during CPR in a Rural Community

Introduction. Cardiopulmonary resuscitation (CPR) in patientswith out-of-hospital cardiac arrest (OHCA) have interruption ofmanual chest compressions for airway management and breathingwhen performed by medical personnel trained by Advanced CardiacLife Support (ACLS) standards. This interruption likely reducesblood flow and possibly survival. Traditional CPR (30:2 compressionsto ventilations) was compared with continuous chest compressions,CCC (also termed Cardiocerebral Resuscitation, CCR) in a ruralcommunity. Methods. A retrospective cohort analysis of three years of traditionalCPR (June 2008 - May 2011) for OHCA was compared tothree years of using CCC protocols (June 2011 - May 2014). Primaryoutcomes were survival at one and six months. Results. There were 58 0HCA patients in the six year study period(June 2008 - May 2014). Forty (69%) received CPR and 18 (31%)received CCC. Two (5%) survived at least one month with CPR andeight (44%) survived at least one month with CCC (p = 0.0007).After six months, 0/40 (0%) who received CPR had survived and6/18 (33%) who received CCC survived (p = 0.0018). For the patientfound in ventricular fibrillation or tachycardia (a shockable rhythm),0/13 (0.0%) survived one month after CPR and 7/9 (78%) survivedwith CCC (p &lt; 0.01). After six months 0/13 (0.0%) survived withCPR and 6/9 (67%) survived with CCC (p &lt; 0.05). Conclusions. For patients in a rural environment with OHCA, CCChad a more favorable outcome than traditional CPR. For the patientfound in ventricular fibrillation or ventricular tachycardia, there wasa profound survival benefit of CCC over CPR.Kans J Med 2018;11(4):110-113

Sensory augmentation with distal touch: The tactile helmet project

The Tactile Helmet is designed to augment a wearer's senses with a long range sense of touch. Tactile specialist animals such as rats and mice are capable of rapidly acquiring detailed information about their environment from their whiskers by using task-sensitive strategies. Providing similar information about the nearby environment, in tactile form, to a human operator could prove invaluable for search and rescue operations, or for partially-sighted people. Two key aspects of the Tactile Helmet are sensory augmentation, and active sensing. A haptic display is used to provide the user with ultrasonic range information. This can be interpreted in addition to, rather than instead of, visual or auditory information. Active sensing systems "are purposive and information-seeking sensory systems, involving task specific control of the sensory apparatus" [1]. The integration of an accelerometer allows the device to actively gate the delivery of sensory information to the user, depending on their movement. Here we describe the hardware, sensory transduction and characterisation of the Tactile Helmet device, before outlining potential use cases and benefits of the system. © 2013 Springer-Verlag Berlin Heidelberg