Long-term, multiwavelength light curves of ultra-cool dwarfs: II. The evolving light curves of the T2. 5 SIMP 0136 & the uncorrelated light curves of the M9 TVLM 513

We present multiwavelength, multi-telescope, ground-based follow-up photometry of the white dwarf WD 1145+017, that has recently been suggested to be orbited by up to six or more, short-period, low- mass, disintegrating planetesimals. We detect 9 significant dips in flux of between 10% and 30% of the stellar flux from our ground-based photometry. We observe transits deeper than 10% on average every ∼3.6 hr in our photometry. This suggests that WD 1145+017 is indeed being orbited by multiple, short-period objects. Through fits to the multiple asymmetric transits that we observe, we confirm that the transit egress timescale is usually longer than the ingress timescale, and that the transit duration is longer than expected for a solid body at these short periods, all suggesting that these objects have cometary tails streaming behind them. The precise orbital periods of the planetesimals in this system are unclear from the transit-times, but at least one object, and likely more, have orbital periods of ∼4.5 hours. We are otherwise unable to confirm the specific periods that have been reported, bringing into question the long-term stability of these periods. Our high precision photometry also displays low amplitude variations suggesting that dusty material is consistently passing in front of the white dwarf, either from discarded material from these disintegrating planetesimals or from the detected dusty debris disk. For the significant transits we observe, we compare the transit depths in the V- and R-bands of our multiwavelength photometry, and find no significant difference; therefore, for likely compositions the radius of single-size particles in the cometary tails streaming behind the planetesimals in this system must be ∼0.15 μm or larger, or ∼0.06 μm or smaller, with 2σ confidence

Evaluation of CB1 receptor knockout mice in the Morris water maze.

ABSTRACT The endocannabinoid system has been proposed to modulate a variety of physiological processes, including those that underlie cognition. The present study tested whether this system is tonically active in learning and memory by comparing CB 1 receptor knockout mice (CB 1 Ϫ/Ϫ ) to wild-type mice (CB 1 ϩ/ϩ ) in several Morris water maze tasks. Also, the effects of three cannabinoid agonists, (WIN 55,, and methanandamide, were evaluated in a working memory procedure. Both genotypes exhibited identical acquisition rates in a fixed platform procedure; however, the CB 1 Ϫ/Ϫ mice demonstrated significant deficits in a reversal task in which the location of the hidden platform was moved to the opposite side of the tank. This phenotype difference was most likely due to an increased perseverance of the CB 1 Ϫ/Ϫ mice in that they continued to return to the original platform location, despite being repeatedly shown the new platform location. In addition, ⌬ 9 -THC (ED 50 ϭ 1.3 mg/ kg), WIN 55,212-2 (ED 50 ϭ 0.35 mg/kg), and methanandamide (ED 50 ϭ 3.2 mg/kg) disrupted the performance of CB 1 ϩ/ϩ mice in the working memory task at doses that did not elicit motivational or sensorimotor impairment as assessed in a cued version of the task. Furthermore, doses of each drug that were maximally disruptive in CB 1 ϩ/ϩ mice were ineffective in either N-(pip- ϩ/ϩ or CB 1 Ϫ/Ϫ mice. These results provide strong evidence that cannabinoids disrupt working memory through a CB 1 receptor mechanism of action, and suggest that the endocannabinoid system may have a role in facilitating extinction and/or forgetting processes

Reconstruction of the neuromuscular junction connectome

Motivation: Unraveling the structure and behavior of the brain and central nervous system (CNS) has always been a major goal of neuroscience. Understanding the wiring diagrams of the neuromuscular junction connectomes (full connectivity of nervous system neuronal components) is a starting point for this, as it helps in the study of the organizational and developmental properties of the mammalian CNS. The phenomenon of synapse elimination during developmental stages of the neuronal circuitry is such an example. Due to the organizational specificity of the axons in the connectomes, it becomes important to label and extract individual axons for morphological analysis. Features such as axonal trajectories, their branching patterns, geometric information, the spatial relations of groups of axons, etc. are of great interests for neurobiologists in the study of wiring diagrams. However, due to the complexity of spatial structure of the axons, automatically tracking and reconstructing them from microscopy images in 3D is an unresolved problem. In this article, AxonTracker-3D, an interactive 3D axon tracking and labeling tool is built to obtain quantitative information by reconstruction of the axonal structures in the entire innervation field. The ease of use along with accuracy of results makes AxonTracker-3D an attractive tool to obtain valuable quantitative information from axon datasets

openWAR: An Open Source System for Evaluating Overall Player Performance in Major League Baseball

Within baseball analytics, there is substantial interest in comprehensive statistics intended to capture overall player performance. One such measure is Wins Above Replacement (WAR), which aggregates the contributions of a player in each facet of the game: hitting, pitching, baserunning, and fielding. However, current versions of WAR depend upon proprietary data, ad hoc methodology, and opaque calculations. We propose a competitive aggregate measure, openWAR, that is based upon public data and methodology with greater rigor and transparency. We discuss a principled standard for the nebulous concept of a "replacement" player. Finally, we use simulation-based techniques to provide interval estimates for our openWAR measure.Comment: 27 pages including supplemen

Colored Motifs Reveal Computational Building Blocks in the C. elegans Brain

Background: Complex networks can often be decomposed into less complex sub-networks whose structures can give hints about the functional organization of the network as a whole. However, these structural motifs can only tell one part of the functional story because in this analysis each node and edge is treated on an equal footing. In real networks, two motifs that are topologically identical but whose nodes perform very different functions will play very different roles in the network. Methodology/Principal Findings: Here, we combine structural information derived from the topology of the neuronal network of the nematode C. elegans with information about the biological function of these nodes, thus coloring nodes by function. We discover that particular colorations of motifs are significantly more abundant in the worm brain than expected by chance, and have particular computational functions that emphasize the feed-forward structure of information processing in the network, while evading feedback loops. Interneurons are strongly over-represented among the common motifs, supporting the notion that these motifs process and transduce the information from the sensor neurons towards the muscles. Some of the most common motifs identified in the search for significant colored motifs play a crucial role in the system of neurons controlling the worm's locomotion. Conclusions/Significance: The analysis of complex networks in terms of colored motifs combines two independent data sets to generate insight about these networks that cannot be obtained with either data set alone. The method is general and should allow a decomposition of any complex networks into its functional (rather than topological) motifs as long as both wiring and functional information is available