Object identification and characterization with hyperspectral imagery to identify structure and function of Natura 2000 habitats

Habitat monitoring of designated areas under the EU Habitats Directive requires every 6 years information on area, range, structure and function for the protected (Annex I) habitat types. First results from studies on heathland areas in Belgium and the Netherlands show that hyperspectral imagery can be an important source of information to assist the evaluation of the habitat conservation status. Hyperspectral imagery can provide continuous maps of habitat quality indicators (e.g., life forms or structure types, management activities, grass, shrub and tree encroachment) at the pixel level. At the same time, terrain managers, nature conservation agencies and national authorities responsible for the reporting to the EU are not directly interested in pixels, but rather in information at the level of vegetation patches, groups of patches or the protected site as a whole. Such local level information is needed for management purposes, e.g., exact location of patches of habitat types and the sizes and quality of these patches within a protected site. Site complexity determines not only the classification success of remote sensing imagery, but influences also the results of aggregation of information from the pixel to the site level. For all these reasons, it is important to identify and characterize the vegetation patches. This paper focuses on the use of segmentation techniques to identify relevant vegetation patches in combination with spectral mixture analysis of hyperspectral imagery from the Airborne Hyperspectral Scanner (AHS). Comparison with traditional vegetation maps shows that the habitat or vegetation patches can be identified by segmentation of hyperspectral imagery. This paper shows that spectral mixture analysis in combination with segmentation techniques on hyperspectral imagery can provide useful information on processes such as grass encroachment that determine the conservation status of Natura 2000 heathland areas to a large extent. A limitation is that both advanced remote sensing approaches and traditional field based vegetation surveys seem to cause over and underestimations of grass encroachment for specific categories, but the first provides a better basis for monitoring if specific species are not directly considered

Relativistic Phenomena in Active Galactic Nuclei

The idea that the radio jets in AGN contain material in relativistic motion is supported by many lines of observational evidence, including morphology, brightness temperature estimated with interferometers and with intrinsic variations, interstellar scintillations, X-rays, and superluminal motion. These are largely independent, and taken together make an irrefutable case for relativistic motion.Comment: 16 pages, 8 Figures. To appear in "Radio Astronomy at 70: from Karl Jansky to microjansky", eds. L.I.Gurvits, S.Frey, S.Rawlings, 2004, EDP Sciences, in pres

Kinematics of parsec-scale structures in AGN: the 2cm VLBA Survey

We are investigating the kinematics of jets in active galactic nuclei on parsec scales by studying a representative population of sources. This study is being carried out using the Very Long Baseline Array at 15 GHz, with more than 800 images taken since 1994. In this contribution we present an overview of the diversity of kinematics for a complete sample of sources.Comment: Proceedings of the 6th European VLBI Network Symposium, Ros E., Porcas R.W., Lobanov, A.P., & Zensus, J.A. (eds), MPIfR, Bonn, Germany. 2 pages, 3 figures, needs evn2002.cls style fil

Variability and Velocity of Superluminal Sources

We investigate the relation between the Doppler factor determined from variations in total flux at 22 and 37 GHz, and the apparent transverse velocity determined from VLBA observations at 2 cm. The data are consistent with the relativistic beaming theory for compact radio sources, in that the distribution of beta_{app}/delta_{var}, for 30 quasars, is roughly consistent with a Monte Carlo simulation. The intrinsic temperature appears to be ~2x10^{10} K, close to the "equipartition value" calculated by Readhead (1994). We deduce the distribution of Lorentz factors for a group of 48 sources; the values range up to about gamma=40.Comment: To be published in "Radio Astronomy at the Fringe", ASP Conf. Ser. Vol. 300, J. A. Zensus, M. H. Cohen, & E. Ros (eds.), 8 pages, 3 figures, needs rafringe.st

Relativistic Beaming and the Intrinsic Properties of Extragalactic Radio Jets

Relations between the observed quantities for a beamed radio jet, apparent transverse speed and apparent luminosity (beta_app,L), and the intrinsic quantities, Lorentz factor and intrinsic luminosity (gamma,L_o), are investigated. The inversion from measured to intrinsic values is not unique, but approximate limits to gamma and L_o can be found using probability arguments. Roughly half the sources in a flux density--limited, beamed sample have a value of gamma close to the measured beta_app. The methods are applied to observations of 119 AGN jets made with the VLBA at 15 GHz during 1994-2002. The results strongly support the common relativistic beam model for an extragalactic radio jet. The (beta_app,L) data are closely bounded by a theoretical envelope, an aspect curve for gamma=32, L_o= 10^25 W/Hz. This gives limits to the maximum values of gamma and L_o in the sample: gamma_max about 32, and L_o,max ~ 10^26 W/Hz. No sources with both high beta_app and low L are observed. This is not the result of selection effects due to the observing limits, which are flux density S>0.5 Jy, and angular velocity mu<4 mas/yr. Many of the fastest quasars have a pattern Lorentz factor gamma_p close to that of the beam, gamma_b, but some of the slow quasars must have gamma_p<<gamma_b. Three of the 10 galaxies in the sample have a superluminal feature, with speeds up to beta_app about 6. The others are at most mildly relativistic. The galaxies are not off-axis versions of the powerful quasars, but Cygnus A might be an exception.Comment: 12 pages, 9 figures, 1 table, accepted for publication in the Astrophysical Journa

Falerii novi (comune di fabrica di Roma, provincia di viterbo, regione lazio)

As part of the AHRC-funded “Beneath the Surface of Roman Republican Cities” project (2015-17), our team is pursuing a full-coverage Ground Penetrating Radar (GPR) survey of the entire intra-mural area of the Roman town of Falerii Novi, in combination with an assessment of the unpublished pottery from the excavations of 1969-75: our objective is to further our knowledge and understanding of the Roman town and its earlier phases of settlement (Launaro et al. 2016; 2017)

HRT for women with premature ovarian insufficiency: a comprehensive review

BACKGROUND: Premature ovarian insufficiency (POI), often and misleadingly referred to as ‘premature menopause’, is defined as a loss of ovarian activity before the age of 40 years and is characterized by irregular or absent periods and reduced fertility. Symptoms include those associated with the natural menopause (night sweats and vaginal dryness), and with the long-term adverse effects of estrogen deficiency (osteoporosis and cardiovascular disease): the latter is believed to explain the shorter life expectancy associated with POI. OBJECTIVE AND RATIONALE: The objective of the current review was to collect all relevant studies supporting recommendations on the indications, treatment options, and risks of hormone replacement therapy (HRT) (estrogen, progestogens and androgens) for women with POI. SEARCH METHODS: The current review was written based on the best available evidence on the topic collected for the recently published ESHRE guideline on the management of women with POI. PUBMED/MEDLINE and the Cochrane library were searched in a stepwise approach. Relevant references were summarized in evidence tables, with assessment of the quality. OUTCOMES: HRT is strongly recommended for women with POI, mainly for vasomotor and genito-urinary symptom relief. In addition, HRT has been shown to have a role in bone protection and probably also in primary prevention of cardiovascular disease. There is little evidence on the optimal type, regimen and dose of HRT; patient preference for route and method of administration of each component of HRT must be considered when prescribing, as should contraceptive needs. In women with POI, physiological replacement of estrogen (and progesterone) is essential for their health, and the controversies that surround the use of HRT in postmenopausal women do not apply. WIDER IMPLICATIONS: New areas of study on HRT for women with POI should focus on life expectancy, quality of life and neurological function. Furthermore, randomized controlled trials comparing transdermal estradiol with oral estrogens with regard to efficacy, patient satisfaction and side effects are urgently needed. STUDY FUNDING/COMPETING INTERESTS: The authors received no funding for the review. The costs for the development of the ESHRE guideline were covered by ESHRE. The authors have no conflicts of interest to disclose

Doppler Boosting, Superluminal Motion, and the Kinematics of AGN Jets

We discuss results from a decade long program to study the fine-scale structure and the kinematics of relativistic AGN jets with the aim of better understanding the acceleration and collimation of the relativistic plasma forming AGN jets. From the observed distribution of brightness temperature, apparent velocity, flux density, time variability, and apparent luminosity, the intrinsic properties of the jets including Lorentz factor, luminosity, orientation, and brightness temperature are discussed. Special attention is given to the jet in M87, which has been studied over a wide range of wavelengths and which, due to its proximity, is observed with excellent spatial resolution. Most radio jets appear quite linear, but we also observe curved non-linear jets and non-radial motions. Sometimes, different features in a given jet appear to follow the same curved path but there is evidence for ballistic trajectories as well. The data are best fit with a distribution of Lorentz factors extending up to gamma ~30 and intrinsic luminosity up to ~10^26 W/Hz. In general, gamma-ray quasars may have somewhat larger Lorentz factors than non gamma-ray quasars. Initially the observed brightness temperature near the base of the jet extend up to ~5x10^13 K which is well in excess of the inverse Compton limit and corresponds to a large excess of particle energy over magnetic energy. However, more typically, the observed brightness temperatures are ~2x10^11 K, i.e., closer to equipartition.Comment: 10 pages, 12 color figures; proceedings of the 5th Stromlo Symposium: Disks, Winds, and Jets - from Planets to Quasars; accepted in Astrophysics & Space Scienc

MOJAVE: monitoring of jets in active galactic nuclei with VLBA experiments. V. Multi-epoch VLBA images

We present images from a long-term program (MOJAVE: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments) to survey the structure and evolution of parsec-scale jet phenomena associated with bright radio-loud active galaxies in the northern sky. The observations consist of 2424 15 GHz Very Long Baseline Array (VLBA) images of a complete flux-density-limited sample of 135 AGNs above declination –20°, spanning the period 1994 August to 2007 September. These data were acquired as part of the MOJAVE and 2 cm Survey programs, and from the VLBA archive. The sample-selection criteria are based on multi-epoch parsec-scale (VLBA) flux density, and heavily favor highly variable and compact blazars. The sample includes nearly all the most prominent blazars in the northern sky, and is well suited for statistical analysis and comparison with studies at other wavelengths. Our multi-epoch and stacked-epoch images show 94% of the sample to have apparent one-sided jet morphologies, most likely due to the effects of relativistic beaming. Of the remaining sources, five have two-sided parsec-scale jets, and three are effectively unresolved by the VLBA at 15 GHz, with essentially all of the flux density contained within a few tenths of a milliarcsecond