What Makes Lyα\alpha Nebulae Glow? Mapping the Polarization of LABd05

"Ly$\alpha$ nebulae" are giant ($\sim$100 kpc), glowing gas clouds in the distant universe. The origin of their extended Ly$\alpha$ emission remains a mystery. Some models posit that Ly$\alpha$ emission is produced when the cloud is photoionized by UV emission from embedded or nearby sources, while others suggest that the Ly$\alpha$ photons originate from an embedded galaxy or AGN and are then resonantly scattered by the cloud. At least in the latter scenario, the observed Ly$\alpha$ emission will be polarized. To test these possibilities, we are conducting imaging polarimetric observations of seven Ly$\alpha$ nebulae. Here we present our results for LABd05, a cloud at $z$ = 2.656 with an obscured, embedded AGN to the northeast of the peak of Ly$\alpha$ emission. We detect significant polarization. The highest polarization fractions $P$ are $\sim$10-20% at $\sim$20-40 kpc southeast of the Ly$\alpha$ peak, away from the AGN. The lowest $P$, including upper-limits, are $\sim$5% and lie between the Ly$\alpha$ peak and AGN. In other words, the polarization map is lopsided, with $P$ increasing from the Ly$\alpha$ peak to the southeast. The measured polarization angles $\theta$ are oriented northeast, roughly perpendicular to the $P$ gradient. This unique polarization pattern suggests that 1) the spatially-offset AGN is photoionizing nearby gas and 2) escaping Ly$\alpha$ photons are scattered by the nebula at larger radii and into our sightline, producing tangentially-oriented, radially-increasing polarization away from the photoionized region. Finally we conclude that the interplay between the gas density and ionization profiles produces the observed central peak in the Ly$\alpha$ emission. This also implies that the structure of LABd05 is more complex than assumed by current theoretical spherical or cylindrical models.Comment: 11 pages, 8 figure

maigesPack: A Computational Environment for Microarray Data Analysis

Microarray technology is still an important way to assess gene expression in molecular biology, mainly because it measures expression profiles for thousands of genes simultaneously, what makes this technology a good option for some studies focused on systems biology. One of its main problem is complexity of experimental procedure, presenting several sources of variability, hindering statistical modeling. So far, there is no standard protocol for generation and evaluation of microarray data. To mitigate the analysis process this paper presents an R package, named maigesPack, that helps with data organization. Besides that, it makes data analysis process more robust, reliable and reproducible. Also, maigesPack aggregates several data analysis procedures reported in literature, for instance: cluster analysis, differential expression, supervised classifiers, relevance networks and functional classification of gene groups or gene networks

Pleasures of the Mind: What Makes Jokes and Insight Problems Enjoyable

In this paper, a parallel analysis of the enjoyment derived from humor and insight problem solving is presented with reference to a \u201cgeneral\u201d Theory of the Pleasures of the Mind (TPM) (Kubovy, 1999) rather than to \u201clocal\u201d theories regarding what makes humor and insight problem solving enjoyable. The similarity of these two cognitive activities has already been discussed in previous literature in terms of the cognitive mechanisms which underpin getting a joke or having an insight experience in a problem solving task. The paper explores whether we can learn something new about the similarities and differences between humor and problem solving by means of an investigation of what makes them pleasurable. In the first part of the paper, the framework for this joint analysis is set. Two descriptive studies are then presented in which the participants were asked to report on their experiences relating to solving visuo-spatial insight problems (Study 1) or understanding cartoons (Study 2) in terms of whether they were enjoyable or otherwise. In both studies, the responses were analyzed with reference to a set of categories inspired by the TPM. The results of Study 1 demonstrate that finding the solution to a problem is associated with a positive evaluation, and the most frequent explanations for this were reported as being Curiosity, Virtuosity and Violation of expectations. The results of Study 2 suggest that understanding a joke (Joy of verification) and being surprised by it (Feeling of surprise) were two essential conditions: when they were not present, the cartoons were perceived as not enjoyable. However, this was not enough to explain the motivations for the choice of the most enjoyable cartoons. Recognizing a Violation of expectations and experiencing a diminishment in the cleverness or awareness initially attributed to the characters in the cartoon were the aspects which were most frequently indicated by the participants to explain why they enjoyed the joke. These findings are evaluated in the final discussion, together with their limitations and potential future developments

Initial '80s Development of Inflated Antennas

State of the art technology was considered in the definition and documentation of a membrane surface suitable for use in a space reflector system for long durations in orbit. Requirements for a metal foil-plastic laminate structural element were determined and a laboratory model of a rigidized element to test for strength characteristics was constructed. Characteristics of antennas ranging from 10 meters to 1000 meters were determined. The basic antenna configuration studied consists of (1) a thin film reflector, (2) a thin film cone, (3) a self-rigidizing structural torus at the interface of the cone and reflector; and (4) an inflation system. The reflector is metallized and, when inflated, has a parabolic shape. The cone not only completes the enclosure of the inflatant, but also holds the antenna feed at its apex. The torus keeps the inflated cone-reflector from collapsing inward. Laser test equipment determined the accuracy of the inflated paraboloids

The syntactic derivations of interrogative verbs in Amis and Kavalan

Interrogative words that denote ‘what’, ‘how’, ‘where’, and ‘how many’ in Amis and Kavalan have the same morphosyntactic distribution as verbs. The present paper argues that their use as verbs is not due to unconstrained lexical idiosyncrasies, but exhibits consistent syntactic and semantic patterns. Their grammatical properties and restrictions follow from the interaction of the following factors: the inherent semantics of interrogative words, the available interpretation of the question where they occur, the verbal structures of the voice markers, and the syntactic principles and constraints like the Head Movement Constraint or the Transparence Condition. The syntactic analysis advocated in this paper can extend to other atypical non-interrogative verbs in the two languages and makes falsifiable predictions about what interrogative words can and cannot be used as verbs

Analytical design and evaluation of an active control system for helicopter vibration reduction and gust response alleviation

An analytical study was conducted to define the basic configuration of an active control system for helicopter vibration and gust response alleviation. The study culminated in a control system design which has two separate systems: narrow band loop for vibration reduction and wider band loop for gust response alleviation. The narrow band vibration loop utilizes the standard swashplate control configuration to input controller for the vibration loop is based on adaptive optimal control theory and is designed to adapt to any flight condition including maneuvers and transients. The prime characteristics of the vibration control system is its real time capability. The gust alleviation control system studied consists of optimal sampled data feedback gains together with an optimal one-step-ahead prediction. The prediction permits the estimation of the gust disturbance which can then be used to minimize the gust effects on the helicopter

Should It Be Curtains for Some of the IMF’s Lending Windows?

Increasing attention is being paid to IMF governance, and the structure and size of the Fund’s lending operations. However, less interest has been shown in the array of lending windows through which the IMF makes resources available. There have nonetheless been clear trends over recent years in the extent to which the windows are used. What discussion has occurred has been largely qualitative. In this paper, and as far as the data allow, we adopt a quantitative approach and focus on the extent to which the economic circumstances in which countries sign extended and concessionary arrangements differ from those in which they sign conventional stand bys. On this basis, we claim that there is a strong case for discontinuing the EFF but for continuing the PRGF. The paper also discusses, more broadly, reforms to the structure of the IMF’s lending windows.