Patrones de abundancia, bioecología y distribución de la termita neotropical sin soldados Compositermes vindai Scheffrahn, 2013 (Isoptera, Termitidae, Apicotermitinae)

The soldierless Neotropical Apicotermitinae is considered among the less known termite groups and its ecological relevance warrants studies about the biology and diversity of their species. We investigated the presence, distribution and relative abundance of the recently described species Compositermes vindai Scheffrahn, 2013 in natural and anthropized ecosystems of northeastern Argentina. Their nests and populations, as well as their presence inside other Termitidae mounds were examined. A standardized sampling protocol for termites was applied at five sites, with 100 x 2 m transects. Worker morphometric data from the surveyed localities are also reported. C. vindai was found in protected environments with little disturbance as well as in other altered ecosystems. The abundance patterns of C. vindai in the sampled areas varied from rare to intermediate and seemed not to be significantly affected by the environmental changes of the sites due to their land uses. The microhabitats occupied were mainly superficial soil and other Termitidae mounds (Cornitermes cumulans Kollar, 1832; Syntermes obtusus Holmgren, 1911 and Cortaritermes fulviceps Silvestri, 1901). C. vindai subterranean and diffuse nests showed a core surrounding by scattered chambers and tunnels extending into the surrounding soil. The small size colonies comprised workers, brachypterous nymphs and white immature larvae. Winged imagoes or primary reproductives were not found. These new records also extend the distribution of C. vindai across the biomes and ecoregions of the Neotropical ecozone and constitute the first reports of C. vindai from Argentina.Las termitas Neotropicales sin soldados de la subfamilia Apicotermitinae, son consideradas uno de los grupos de isópteros menos conocidos, por lo que resulta importante analizar sus rasgos biológicos y diversidad. Se investigó la presencia, distribución y abundancia relativa de la especie recientemente descripta Compositermes vindai Scheffrahn, 2013 en ecosistemas naturales y antropizados del noreste de Argentina. Se examinaron sus nidos y poblaciones, así como su presencia en los montículos de otras termitas. Se aplicó un protocolo estandarizado de muestreo para isópteros en cinco sitios, con transectas de 100 x 2 m. También se registraron datos morfométricos de obreras. C. vindai fue detectada en ambientes protegidos poco perturbados, así como en otros ecosistemas alterados. Los patrones de abundancia de C. vindai en estas áreas variaron de rara a intermedia y la especie pareció no ser afectada de manera significativa por los cambios ambientales derivados de diferentes usos de la tierra. Los microhábitats ocupados fueron principalmente suelo superficial y montículos de otras Termitidae (Cornitermes cumulans Kollar, 1832; Syntermes obtusus Holmgren, 1911 y Cortaritermes fulviceps Silvestri, 1901). Los nidos subterráneos y difusos de C. vindai mostraron un núcleo rodeado por cámaras dispersas y túneles que se extendían en el suelo circundante. Las pequeñas colonias estuvieron compuestas por obreras, ninfas braquípteras e inmaduros. No se hallaron individuos alados ni reproductores primarios. Estos nuevos registros extienden la distribución de C. vindai a otros biomas y ecorregiones de la ecozona Neotropical y constituyen los primeros hallazgos de C. vindai para Argentina

Tests of Non-Causality Under Markov Assumptions for Qualitative Panel Data

For many years, social scientists have been interested in obtaining testable definitions of causality [C. W. Granger (1969)]. Recent works include those of G. Chamberlain (1982) and J. P. Florens and M. Mouchart (1982). The present paper first clarifies the results of these latter papers by considering a unifying definition of non-causality. Then, log-likelihood ratio (LR) tests for non-causality are derived for qualitative panel data under the minimal assumption that one series is Markov. LR tests for the Markov property are also obtained. Both test statistics have closed forms. These tests thus provide a readily applicable procedure for testing non-causality on qualitative panel data. Finally, the tests are applied to French Business Survey data in order to test the hypothesis that price changes from period to period are strictly exogenous to disequilibria appearing within periods

Incentivizing High Quality Crowdwork

We study the causal effects of financial incentives on the quality of crowdwork. We focus on performance-based payments (PBPs), bonus payments awarded to workers for producing high quality work. We design and run randomized behavioral experiments on the popular crowdsourcing platform Amazon Mechanical Turk with the goal of understanding when, where, and why PBPs help, identifying properties of the payment, payment structure, and the task itself that make them most effective. We provide examples of tasks for which PBPs do improve quality. For such tasks, the effectiveness of PBPs is not too sensitive to the threshold for quality required to receive the bonus, while the magnitude of the bonus must be large enough to make the reward salient. We also present examples of tasks for which PBPs do not improve quality. Our results suggest that for PBPs to improve quality, the task must be effort-responsive: the task must allow workers to produce higher quality work by exerting more effort. We also give a simple method to determine if a task is effort-responsive a priori. Furthermore, our experiments suggest that all payments on Mechanical Turk are, to some degree, implicitly performance-based in that workers believe their work may be rejected if their performance is sufficiently poor. Finally, we propose a new model of worker behavior that extends the standard principal-agent model from economics to include a worker's subjective beliefs about his likelihood of being paid, and show that the predictions of this model are in line with our experimental findings. This model may be useful as a foundation for theoretical studies of incentives in crowdsourcing markets.Comment: This is a preprint of an Article accepted for publication in WWW \c{opyright} 2015 International World Wide Web Conference Committe

Isokinetic muscle strengthening after acquired cerebral damage: A literature review

AbstractObjectiveIsokinetic strengthening is a rehabilitation technique rarely used in stroke patients. However, the potential benefits of force and endurance training in this population are strongly suspected.MethodThis literature review synthesizes the results of clinical trials on this topic. The research was conducted on PubMed, using “Stroke”, “rehabilitation”, “isokinetic”, “upper limb” and “training” as keywords.ResultsSeventeen studies focusing on the use of isokinetics in assessment or rehabilitation (six studies) following stroke were reviewed. For the lower limb, muscle strength and walking ability improved after isokinetic rehabilitation programs. For the upper limb, the only two studies found in the literature suggest improvement in the strength of the trained muscles, of grip force, of the Fugl-Meyer motor score and of global functional capacities. This review does not reveal any consensus on the protocols to be implemented: type of muscle contraction, velocities….ConclusionWhile isokinetic strengthening has not proven its efficiency in rehabilitation of the upper limb following stroke, its interest with regard to rehabilitation of the lower limbs has been recognized. Randomized controlled trials in this field are necessary to confirm its efficiency, especially concerning upper arm rehabilitation

Public Good Overprovision by a Manipulative Provider

We study contracting between a public good provider and users with private valuations of the good. We show that, once the provider extracts the users' private information, she benefits from manipulating the collective information received from all users when communicating with them. We derive conditions under which such manipulation determines the direction of distortions in public good provision. If the provider is non-manipulative, the public good is always underprovided, whereas overprovision occurs with a manipulative provider. With overprovision, not only high-valuation users, but also low-valuation users may obtain positive rents—users may prefer facing a manipulative provider.Peer Reviewe

On the Investigation of a Novel Dual-Control-Gate Floating Gate Transistor for VCO Applications

A new MOS device called Dual-Control Gate Floating Gate Transistor (DCG-FGT) is used as a building block in analog design. This device offers new approaches in circuit design and allows developing new functionalities through two operating modes: Threshold Voltage Adjustable Mode, where the DCG-FGT behaves like a MOS transistor with an electrically adjustable threshold voltage. Mixer Signal Mode where the DCG-FGT can mix two independent signals on its floating gate. This device is developed to be fully compliant with CMOS Non Volatile Memory (NVM) process. An electrical model of the DCG-FGT has been implemented in an electrical simulator to be available for analog design. A DCG-FGT based ring oscillator is studied in this paper

Inner Space Preserving Generative Pose Machine

Image-based generative methods, such as generative adversarial networks (GANs) have already been able to generate realistic images with much context control, specially when they are conditioned. However, most successful frameworks share a common procedure which performs an image-to-image translation with pose of figures in the image untouched. When the objective is reposing a figure in an image while preserving the rest of the image, the state-of-the-art mainly assumes a single rigid body with simple background and limited pose shift, which can hardly be extended to the images under normal settings. In this paper, we introduce an image "inner space" preserving model that assigns an interpretable low-dimensional pose descriptor (LDPD) to an articulated figure in the image. Figure reposing is then generated by passing the LDPD and the original image through multi-stage augmented hourglass networks in a conditional GAN structure, called inner space preserving generative pose machine (ISP-GPM). We evaluated ISP-GPM on reposing human figures, which are highly articulated with versatile variations. Test of a state-of-the-art pose estimator on our reposed dataset gave an accuracy over 80% on PCK0.5 metric. The results also elucidated that our ISP-GPM is able to preserve the background with high accuracy while reasonably recovering the area blocked by the figure to be reposed.Comment: http://www.northeastern.edu/ostadabbas/2018/07/23/inner-space-preserving-generative-pose-machine