1,720 research outputs found

    Spatially Invariant Coding of Numerical Information in Functionally Defined Subregions of Human Parietal Cortex

    Get PDF
    Macaque electrophysiology has revealed neurons responsive to number in lateral (LIP) and ventral (VIP) intraparietal areas. Recently, fMRI pattern recognition revealed information discriminative of individual numbers in human parietal cortex but without precisely localizing the relevant sites or testing for subregions with different response profiles. Here, we defined the human functional equivalents of LIP (feLIP) and VIP (feVIP) using neurophysiologically motivated localizers. We applied multivariate pattern recognition to investigate whether both regions represent numerical information and whether number codes are position specific or invariant. In a delayed number comparison paradigm with laterally presented numerosities, parietal cortex discriminated between numerosities better than early visual cortex, and discrimination generalized across hemifields in parietal, but not early visual cortex. Activation patterns in the 2 parietal regions of interest did not differ in the coding of position-specific or position-independent number information, but in the expression of a numerical distance effect which was more pronounced in feLIP. Thus, the representation of number in parietal cortex is at least partially position invariant. Both feLIP and feVIP contain information about individual numerosities in humans, but feLIP hosts a coarser representation of numerosity than feVIP, compatible with either broader tuning or a summation cod

    Occurrence of the Old World bug Megacopta cribraria (Fabricius) (Heteroptera: Plataspidae) in Georgia: a serious home invader and potential legume pest

    Get PDF
    Specimens of Megacopta cribraria (Fabricius) were collected in northern Georgia in late October 2009, where they were invading homes in large numbers. This is the first known occurrence of this species and the family Plataspidae in the New World. Megacopta cribraria was previously known from Asia and Australia. A key is provided to separate Plataspidae from other families of Pentatomoidea in America North of Mexico. A diagnosis and figures are provided to facilitate recognition of M. cribraria. Reported host plants and other aspects of the biology of this species are reviewed. Megacopta cribraria is considered a pest of numerous legumes in Asia, has the potential to provide biological control of kudzu, Pueraria montana var. lobata (Willd.) Ohwi, (Fabaceae) and likely will continue to be a household pest in the vicinity of kudzu fields as well as become a pest of North American legume crops

    Discovery of new TeV supernova remnant shells in the Galactic plane with H.E.S.S

    Full text link
    Supernova remnants (SNRs) are prime candidates for efficient particle acceleration up to the knee in the cosmic ray particle spectrum. In this work we present a new method for a systematic search for new TeV-emitting SNR shells in 2864 hours of H.E.S.S. phase I data used for the H.E.S.S. Galactic Plane Survey. This new method, which correctly identifies the known shell morphologies of the TeV SNRs covered by the survey, HESS J1731-347, RX 1713.7-3946, RCW 86, and Vela Junior, reveals also the existence of three new SNR candidates. All three candidates were extensively studied regarding their morphological, spectral, and multi-wavelength (MWL) properties. HESS J1534-571 was associated with the radio SNR candidate G323.7-1.0, and thus is classified as an SNR. HESS J1912+101 and HESS J1614-518, on the other hand, do not have radio or X-ray counterparts that would permit to identify them firmly as SNRs, and therefore they remain SNR candidates, discovered first at TeV energies as such. Further MWL follow up observations are needed to confirm that these newly discovered SNR candidates are indeed SNRs

    First record of \u3ci\u3eOrsilochides scurrilis\u3c/i\u3e (Stål) (Hemiptera: Heteroptera: Scutelleridae: Pachycorinae) in the United States, with notes on the biology and distribution of U.S. species of \u3ci\u3eOrsilochides\u3c/i\u3e Kirkaldy

    Get PDF
    Orsilochides scurrilis (Stål) (Hemiptera: Heteroptera: Scutelleridae) is reported from the United States for the first time based on a specimen collected in Santa Cruz County, Arizona. A key to separate the U.S. species of Orsilochides Kirkaldy is provided. In addition, host plant records and distribution of the other two species of Orsilochides that occur in the U.S., Orsilochides guttata (Herrich-Schäffer) and Orsilochides stictica (Dallas), are analyzed through a combination of digital photo records and museum specimens

    The ideal gas as an urn model: derivation of the entropy formula

    Full text link
    The approach of an ideal gas to equilibrium is simulated through a generalization of the Ehrenfest ball-and-box model. In the present model, the interior of each box is discretized, {\it i.e.}, balls/particles live in cells whose occupation can be either multiple or single. Moreover, particles occasionally undergo random, but elastic, collisions between each other and against the container walls. I show, both analitically and numerically, that the number and energy of particles in a given box eventually evolve to an equilibrium distribution WW which, depending on cell occupations, is binomial or hypergeometric in the particle number and beta-like in the energy. Furthermore, the long-run probability density of particle velocities is Maxwellian, whereas the Boltzmann entropy lnW\ln W exactly reproduces the ideal-gas entropy. Besides its own interest, this exercise is also relevant for pedagogical purposes since it provides, although in a simple case, an explicit probabilistic foundation for the ergodic hypothesis and for the maximum-entropy principle of thermodynamics. For this reason, its discussion can profitably be included in a graduate course on statistical mechanics.Comment: 17 pages, 3 figure

    Understanding Risk Perception and Xenophobic Attitudes during the Coronavirus Disease 2019 (COVID-19) Pandemic in the United States

    Get PDF
    Introduction: There have been over 87 million cases of Coronavirus Disease 2019 (COVID-19) in the United States (US). Objective: The objective of this study was to develop a novel questionnaire to assess risk perception of COVID-19 and xenophobic attitudes among adults in the US at the beginning of the pandemic. Methods: An anonymous self-report questionnaire was developed for this study in February 2020, and was distributed using convenience sampling from March 10 to March 25, 2020. The questionnaire assessed knowledge and risk perceptions of COVID-19, as well as attitudes toward individuals of various races and ethnicities. Results: 662 US adults completed the questionnaire. On a scale from 1 (low) to 5 (high), the mean risk perception was 3.44. Those with knowledge of COVID-19 and higher education levels reported higher risk perception and higher feelings of warmth towards Asian people. Forty percent of the sample had recently witnessed or experienced anti-Asian attitudes at the time of the survey. The majority of participants reported having heard about COVID-19 from news media, social media, and family or friends. Conclusions: Our sample had a moderate level of risk perception, potentially due to the time period of data collection (i.e., early in the pandemic course). The results suggest that knowledge about COVID-19 informed perceived risk and affected willingness to engage in healthy protective behaviors. Our study provides historic context of how people perceived the virus at the beginning of the pandemic, and gives insight into the aftermaths regarding quarantine and attitudes towards Asian Americans

    Perceiving numerosity from birth

    Get PDF

    Age and Male Sexuality: "Queer Space" in the Roman Bathhouse?

    Get PDF
    Scholars have conceived of the life-course stages of the boy and adult male by way of a typically dichotomous construction of active/passive male sexuality. This binary scheme, presented uncritically in much modern scholarship, dictates that boys assumed the passive role in male-to-male sex until roughly the age of 18-20 or the occasion of their first shave, while adults took the active role. This view implies that male sexual relations were pederastic and could be viewed as part of a rudimentary sexual development of a boy to a man, from passive to active, provided he was of free status. Conversely, men who behaved as boys (i.e., were pas-sive) were regarded as 'abnormal', and men who slept with free boys were regarded as criminal

    Chandra detection of diffuse X-ray emission from the globular cluster Terzan 5

    Full text link
    Terzan 5, a globular cluster (GC) prominent in mass and population of compact objects, is searched for diffuse X-ray emission, as proposed by several models. We analyzed the data of an archival Chandra observation of Terzan 5 to search for extended diffuse X-ray emission outside the half-mass radius of the GC. We removed detected point sources from the data to extract spectra from diffuse regions around Terzan 5. The Galactic background emission was modeled by a 2-temperature thermal component, which is typical for Galactic diffuse emission. We detected significant diffuse excess emission above the particle background level from the whole field-of-view. The surface brightness appears to be peaked at the GC center and decreases smoothly outwards. After the subtraction of particle and Galactic background, the excess spectrum of the diffuse emission between the half-mass radius and 3' can be described by a power-law model with photon index Γ\Gamma = 0.9±\pm0.5 and a surface flux of FX_X = (1.17±\pm0.16) 107^{-7} erg s1^{-1} cm2^{-2} sr1^{-1} in the 1--7 keV band. We estimated the contribution from unresolved point sources to the observed excess to be negligible. The observations suggest that a purely thermal origin of the emission is less likely than a non-thermal scenario. However, from simple modeling we cannot identify a clearly preferred scenario.Comment: 6 pages, 4 figures, accepted for publication by A&
    corecore