888 research outputs found

    Ecosystem Indicators for Southeast Florida Beaches

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    Beaches are landscapes valued greatly by society that, when left intact, support both ecological processes and sustainable use. In Southeast Florida, alteration of beaches for human activities has resulted in substantial loss of naturally functioning beach habitat and reduced biological diversity. Of particular importance is the impact on beach ecosystems by the nearby urban environment. Beaches are dynamic ecosystems that require space to respond to natural or anthropogenic drivers and pressures. In Southeast Florida urban development has restricted or eliminated the ability of most beaches to react in a manner that conserves the natural beach ecosystem. The frequent result has been oceanfront areas with little or no intact habitat and limited opportunities for restoration, though disturbed beaches may still provide opportunities for ocean access, recreation, and other socioeconomic benefits in highly urbanized areas. In this study we present a framework for selecting relevant ecosystem and human dimension indicators for the beaches of Southeast Florida based on a conceptual ecosystem model. To capture the level of beach disturbance relatively pristine beaches and heavily altered beaches are endpoints in a continuum of beach development. Across this continuum nine indicators were developed to quantify beach condition. For ecosystem and human dimension assessment purposes, beaches were placed in one of two overarching categories: undeveloped to relatively undeveloped, or developed to highly developed. Nine selected indicators are then assessed as good (3), fair (2), or poor (1). The indicator scores are then summed to produce a total condition score for a particular beach. This simple ‘stop-light’ method is applicable even when there are limited data and provides a useful relative determination of ecosystem condition. Case studies employing this methodology are presented for three Southeast Florida beaches ranging from mostly natural to highly developed condition. The indicators directly address both ecosystem and human dimension goals to maintain healthy, sustainable, and useable beaches and shorelines in Southeast Florida. They balance the ecological benefit of remaining natural beaches with the societal benefit of recreational opportunities and access for a beach that can no longer sustain a suitable ecosystem. Each indicator is interpreted in the context of the trade-offs among multiple ecosystem and human dimension services provided by most beaches in Southeast Florida

    The Common Body of Knowledge: A Framework to Promote Relevant Information Security Research

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    This study proposes using an established common body of knowledge (CBK) as one means of organizing information security literature. Consistent with calls for more relevant information systems (IS) research, this industrydeveloped framework can motivate future research towards topics that are important to the security practitioner. In this review, forty-eight articles from ten IS journals from 1995 to 2004 are selected and cross-referenced to the ten domains of the information security CBK. Further, we distinguish articles as empirical research, frameworks, or tutorials. Generally, this study identified a need for additional empirical research in every CBK domain including topics related to legal aspects of information security. Specifically, this study identified a need for additional IS security research relating to applications development, physical security, operations security, and business continuity. The CBK framework is inherently practitioner oriented and using it will promote relevancy by steering IS research towards topics important to practitioners. This is important considering the frequent calls by prominent information systems scholars for more relevant research. Few research frameworks have emerged from the literature that specifically classify the diversity of security threats and range of problems that businesses today face. With the recent surge of interest in security, the need for a comprehensive framework that also promotes relevant research can be of great value

    H0LiCOW III. Quantifying the effect of mass along the line of sight to the gravitational lens HE 0435-1223 through weighted galaxy counts

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    Based on spectroscopy and multiband wide-field observations of the gravitationally lensed quasar HE 0435-1223, we determine the probability distribution function of the external convergence κext\kappa_\mathrm{ext} for this system. We measure the under/overdensity of the line of sight towards the lens system and compare it to the average line of sight throughout the universe, determined by using the CFHTLenS as a control field. Aiming to constrain κext\kappa_\mathrm{ext} as tightly as possible, we determine under/overdensities using various combinations of relevant informative weighing schemes for the galaxy counts, such as projected distance to the lens, redshift, and stellar mass. We then convert the measured under/overdensities into a κext\kappa_\mathrm{ext} distribution, using ray-tracing through the Millennium Simulation. We explore several limiting magnitudes and apertures, and account for systematic and statistical uncertainties relevant to the quality of the observational data, which we further test through simulations. Our most robust estimate of κext\kappa_\mathrm{ext} has a median value κextmed=0.004\kappa^\mathrm{med}_\mathrm{ext} = 0.004 and a standard deviation of σκ=0.025\sigma_\kappa = 0.025. The measured σκ\sigma_\kappa corresponds to 2.5%2.5\% uncertainty on the time delay distance, and hence the Hubble constant H0H_0 inference from this system. The median κextmed\kappa^\mathrm{med}_\mathrm{ext} value is robust to ∼0.005\sim0.005 (i.e. ∼0.5%\sim0.5\% on H0H_0) regardless of the adopted aperture radius, limiting magnitude and weighting scheme, as long as the latter incorporates galaxy number counts, the projected distance to the main lens, and a prior on the external shear obtained from mass modeling. The availability of a well-constrained κext\kappa_\mathrm{ext} makes \hequad\ a valuable system for measuring cosmological parameters using strong gravitational lens time delays.Comment: 24 pages, 17 figures, 6 tables. Submitted to MNRA

    H5N1 Clade 2.2 Polymorphism Tracing Identifies Influenza Recombination and Potential Vaccine Targets

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    Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997 1. The number of confirmed human cases now exceeds 300 and the associated Case Fatality Rate exceeds 60% 2. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases 3.4. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift 5. We traced polymorphism acquisition in Clade 2.2 sequences. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, Clade 2.2 sub-clades in Egypt, Russia and Ghana. These changes are not easily explained by the current theory of “random mutation” through copy error, and are more easily explained by recombination with a common source. This conclusion is supported by additional polymorphisms shared by Clade 2.2 isolates in Egypt, Nigeria and Germany including aggregation of regional polymorphisms from each of these areas into a single Nigerian human hemagglutinin gene

    Polarities and field configurations of the vertex components of the human auditory evoked response: A reinterpretation

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    The cephalic spatial distributions and phase relationships of the late components, N1 and P2, of the auditory evoked response, elicited by repetitive moderate-intensity tone pips, were assessed in man with a non-cephalic reference. There was no evidence of a polarity reversal at any site on the head, failing to confirm Vaughan and Ritter's (1970) sylvian phase reversal hypothesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33589/1/0000093.pd

    H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H0H_0

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    We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033-4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 years of data obtained by the COSmological MOnitoring of GRAvItational Lenses (COSMOGRAIL) collaboration, (2) high-resolution Hubble Space Telescope\textit{Hubble Space Telescope} imaging, (3) a measurement of the velocity dispersion of the lens galaxy based on ESO-MUSE data, and (4) multi-band, wide-field imaging and spectroscopy characterizing the lens environment. We account for all known sources of systematics, including the influence of nearby perturbers and complex line-of-sight structure, as well as the parametrization of the light and mass profiles of the lensing galaxy. After unblinding, we determine the effective time-delay distance to be 4784−248+399 Mpc4784_{-248}^{+399}~\mathrm{Mpc}, an average precision of 6.6%6.6\%. This translates to a Hubble constant H0=71.6−4.9+3.8 km s−1 Mpc−1H_{0} = 71.6_{-4.9}^{+3.8}~\mathrm{km~s^{-1}~Mpc^{-1}}, assuming a flat Λ\LambdaCDM cosmology with a uniform prior on Ωm\Omega_\mathrm{m} in the range [0.05, 0.5]. This work is part of the H0H_0 Lenses in COSMOGRAIL's Wellspring (H0LiCOW) collaboration, and the full time-delay cosmography results from a total of six strongly lensed systems are presented in a companion paper (H0LiCOW XIII).Comment: Version accepted by MNRAS. 29 pages including appendix, 17 figures, 6 tables. arXiv admin note: text overlap with arXiv:1607.0140

    Foveal and extrafoveal influences on the topography of the visually evoked, early negative potential in man

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    Variations in topographic characteristics of the early negative potential of the human, flash-evoked cerebral response were related to (1) a graduated series of stimulus sizes subtending visual angles from 1[deg] to 32[deg], and (2) a graduated series of central opacities subtending visual angles from 1[deg] to 16[deg] placed within a 32[deg] stimulus.The longitudinal field pattern of the early negative potential was shown to be a function of the spatial characteristics of the visual stimulus. Foveal stimulation produced a local, early negative potential in the occipital region, generally associated with surface-positive activity anteriorly, whereas peripheral stimulation gave a widespread early negative potential, relatively less prominent in the occipital region than in preoccipital areas. Intermediate field-gradient configurations resulted from various combinations of foveal, parafoveal and peripheral stimulation.The effect of addition of extrafoveal to foveal stimulation upon the magnitude of the occipital early negative potential proved to be subject-dependent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34054/1/0000332.pd

    The Common Body of Knowledge: A Framework to Promote Relevant Information Security Research

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    This study proposes using an established common body of knowledge (CBK) as one means of organizing information security literature. Consistent with calls for more relevant information systems (IS) research, this industrydeveloped framework can motivate future research towards topics that are important to the security practitioner. In this review, forty-eight articles from ten IS journals from 1995 to 2004 are selected and cross-referenced to the ten domains of the information security CBK. Further, we distinguish articles as empirical research, frameworks, or tutorials. Generally, this study identified a need for additional empirical research in every CBK domain including topics related to legal aspects of information security. Specifically, this study identified a need for additional IS security research relating to applications development, physical security, operations security, and business continuity. The CBK framework is inherently practitioner oriented and using it will promote relevancy by steering IS research towards topics important to practitioners. This is important considering the frequent calls by prominent information systems scholars for more relevant research. Few research frameworks have emerged from the literature that specifically classify the diversity of security threats and range of problems that businesses today face. With the recent surge of interest in security, the need for a comprehensive framework that also promotes relevant research can be of great value

    Intrinsic Absorption in the Spectrum of Mrk 279: Simultaneous Chandra, FUSE, and STIS Observations

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    We present a study of the intrinsic X-ray and far-ultraviolet absorption in the Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from the Chandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE). We also present FUSE observations made at three additional epochs. We detect the Fe K-alpha emission line in the Chandra spectrum, and its flux is consistent with the low X-ray continuum flux level of Mrk 279 at the time of the observation. Due to low signal-to-noise ratios in the Chandra spectrum, no O VII or O VIII absorption features are observable in the Chandra data, but the UV spectra reveal strong and complex absorption from HI and high-ionization species such as O VI, N V, and C IV, as well as from low-ionization species such as C III, N III, C II, and N II in some velocity components. The far-UV spectral coverage of the FUSE data provides information on high-order Lyman series absorption, which we use to calculate the optical depths and line and continuum covering fractions in the intrinsic HI absorbing gas in a self-consistent fashion. The UV continuum flux of Mrk 279 decreases by a factor of ~7.5 over the time spanning these observations and we discuss the implications of the response of the absorption features to this change. From arguments based on the velocities, profile shapes, covering fractions and variability of the UV absorption, we conclude that some of the absorption components, particularly those showing prominent low-ionization lines, are likely associated with the host galaxy of Mrk 279, and possibly with its interaction with a close companion galaxy, while the remainder arises in a nuclear outflow.Comment: To appear in 2004 May ApJS; double-column format; 58 pages, incl. 29 figures, 9 tables; minor changes to tex

    Concurrent Acquisition of a Single Nucleotide Polymorphism in Diverse Influenza H5N1 Clade 2.2 Sub-clades

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    Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997. The number of confirmed human cases now exceeds 300, and the associated Case Fatality Rate exceeds 60%. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, clade 2.2 sub-clades in Egypt, Russia, and Ghana. These changes are not easily explained by the current theory of “random mutation” through copy error, and are more easily explained by recombination with a common source. This conclusion is supported by additional polymorphisms shared by clade 2.2 isolates in Egypt and Germany
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