147 research outputs found
Kajian Penerapan Green Procurement Pada Proyek Infrastruktur Jalan Di Provinsi Nusa Tenggara Timur
The issue of global warming and climate change is an environmental issue that the world\u27s problems. Countermeasures are now established is sustainable development. One factor supporting sustainable development is an alternative device in the areas of procurement, that is green procurement. Determining the winner of the procurement system is noticed additional aspects, namely social, economic and environmental which in practice is still not determined the weight of each of the environmentally friendly aspects. The purpose of this study was to determine the weighting of the criteria for selecting a winner in the green procurement system and determine the relationship between environmental criteria. Data analysis technique using Analytical Network Process, in order to obtain a priority basis and weighting of each criterion so that it can be described the relationship between the criteria. The results of the study in the opinion of all respondents consisting of qualified contractors large and medium enterprises as well as the Procurement Services Unit predominant aspects in the procurement of environmentally friendly is a social aspect to the criteria that affect the human resources with the weight percentage is 10.40%. In these criteria there are sub-criteria that support namely the availability of experts and skilled workers, the availability of experts and skilled workers by level of education and experience as well as working procedures with the weight percentage of each sub-criteria 33,33%
The composite starburst/AGN nature of the superwind galaxy NGC 4666
We report the discovery of a Compton-thick AGN and of intense star-formation
activity in the nucleus and disk, respectively, of the nearly edge-on superwind
galaxy NGC 4666. Spatially unresolved emission is detected by BeppoSAX only at
energies <10 keV, whereas spatially resolved emission from the whole disk is
detected by XMM-Newton. A prominent (EW ~ 1-2 keV) emission line at ~6.4 keV is
detected by both instruments. From the XMM-Newton data alone the line is
spectrally localized at E ~ 6.42 +/- 0.03 keV, and seems to be spatially
concentrated in the nuclear region of NGC 4666. This, together with the
presence of a flat (Gamma ~ 1.3) continuum in the nuclear region, suggests the
existence of a strongly absorbed (i.e., Compton-thick) AGN, whose intrinsic
2-10 keV luminosity is estimated to be L_{2-10} > 2 x 10^{41} erg/s. At
energies <1 keV the integrated (BeppoSAX) spectrum is dominated by a ~0.25 keV
thermal gas component distributed throughout the disk (resolved by XMM-Newton).
At energies ~2-10 keV, the integrated spectrum is dominated by a steep (G > 2)
power-law (PL) component. The latter emission is likely due to unresolved
sources with luminosity L ~ 10^{38} - 10^{39} erg/s that are most likely
accreting binaries (with BH masses <8 M_sun). Such binaries, which are known to
dominate the X-ray point-source luminosity in nearby star-forming galaxies,
have Gamma ~ 2 PL spectra in the relevant energy range. A Gamma ~ 1.8 PL
contribution from Compton scattering of (the radio-emitting) relativistic
electrons by the ambient FIR photons may add a truly diffuse component to the
2-10 keV emission.Comment: A&A, in press (10 pages, 14 figures.) Full gzipped psfile obtainable
from http://www.bo.iasf.cnr.it/~malaguti/r_stuff.htm
Galactic star-formation rates gauged by stellar end-products
Young galactic X-ray point sources (XPs) closely trace the ongoing star
formation in galaxies. From measured XP number counts we extract the collective
2-10 keV luminosity of young XPs, L_yXP, which we use to gauge the current
star-formation rate (SFR) in galaxies. We find that, for a sample of local
star-forming galaxies (i.e., normal spirals and mild starbursts), L_yXP
correlates linearly with the SFR over three decades in luminosity. A separate,
high-SFR sample of starburst ULIRGs can be used to check the calibration of the
relation. Using their (presumably SF-related) total 2-10 keV luminosities we
find that these sources satisfy the SFR-L_yXP relation, as defined by the
weaker sample, and extend it to span about 5 decades in luminosity. The
SFR-L_yXP relation is likely to hold also for distant Hubble Deep Field North
galaxies, especially so if these high-SFR objects are similar to the (more
nearby) ULIRGs. It is argued that the SFR-L_yXP relation provides the most
adequate X-ray estimator of instantaneous SFR by the phenomena characterizing
massive stars from their birth (FIR emission from placental dust clouds)
through their death as compact remnants (emitting X-rays by accreting from a
close donor). For local, low/intermediate-SFR galaxies, the simultaneous
existence of a correlation of the instantaneous SFR with the total 2-10 keV
luminosity, which traces the SFR integrated over (approximately) the last Gyr,
suggests that during such epoch the SF in these galaxies has been proceeding at
a relatively constant rate.Comment: A&A, in press (15 pages, 8 figures
Near-IR observations of the HE0450-2958 system: discovery of a second AGN?
The QSO HE0450-2958 was brought to the front scene by the non-detection of
its host galaxy and strong upper limits on the latter's luminosity. The QSO is
also a powerful infrared emitter, in gravitational interaction with a strongly
distorted UltraLuminous InfraRed companion galaxy. We investigate the
properties of the companion galaxy, through new near- and mid-infrared
observations of the system obtained with NICMOS onboard HST, ISAAC and VISIR on
the ESO VLT. The companion galaxy is found to harbour a point source revealed
only in the infrared, in what appears as a hole or dark patch in the optical
images. Various hypotheses on the nature of this point source are analyzed and
it is found that the only plausible one is that it is a strongly reddened AGN
hidden behind a thick dust cloud. The hypothesis that the QSO supermassive
black hole might have been ejected from the companion galaxy in the course of a
galactic collision involving 3-body black holes interaction is also reviewed,
on the basis of this new insight on a definitely complex system.Comment: 8 pages, 8 figures, accepted for publication in MNRA
Black hole masses and Eddington ratios of AGNs at z < 1: Evidence of retriggering for a representative sample of X-ray-selected AGNs
We estimated black hole masses and Eddington ratios for a sample of X-ray-selected active galactic nuclei (AGNs) in the fields covered by the Great Observatory Origins Deep Survey (GOODS). The spanned ranges in redshift (0.4<z<1) and hard X-ray luminosity (1042<~LX<~4
71043 ergs s-1) allow us to study a representative subsample of the main contributors to the 2-10 keV X-ray background. Nuclear and bulge magnitudes in four bands have been measured via a two-dimensional decomposition applied to HST ACS images. Using the black hole versus bulge luminosity relation and the intrinsic nuclear emission, we derived the black hole mass and the AGN bolometric luminosity. We find in our sample that (1) the X-ray-to-optical indices are larger than in optically selected QSOs, as expected due to the X-ray selection); (2) the X-ray bolometric corrections are generally small, suggesting a decrease with the nuclear luminosity; (3) the Eddington ratios are about a factor 10 below the values found at higher redshift and luminosity; (4) the central black holes have rather large masses; and (5) at least for z~1) also for these smaller black holes
Feasibility and reference values of left atrial longitudinal strain imaging by two-dimensional speckle tracking
<p>Abstract</p> <p>Background</p> <p>The role of speckle tracking in the assessment of left atrial (LA) deformation dynamics is not established. We sought to determine the feasibility and reference ranges of LA longitudinal strain indices measured by speckle tracking in a population of normal subjects.</p> <p>Methods</p> <p>In 60 healthy individuals, peak atrial longitudinal strain (PALS) and time to peak longitudinal strain (TPLS) were measured using a 12-segment model for the left atrium. Values were obtained by averaging all segments (global PALS and TPLS) and by separately averaging segments measured in the two apical views (4- and 2-chamber average PALS and TPLS).</p> <p>Results</p> <p>Adequate tracking quality was achieved in 97% of segments analyzed. Inter and intra-observer variability coefficients of measurements ranged between 2.9% and 5.4%. Global PALS was 42.2 ± 6.1% (5–95° percentile range 32.2–53.2%), and global TPLS was 368 ± 30 ms (5–95° percentile range 323–430 ms). The 2-chamber average PALS was slightly higher than the 4-chamber average PALS (44.3 ± 6.0% vs 40.1 ± 7.9%, p < 0.0001), whereas no differences in TPLS were found (p = 0.93).</p> <p>Conclusion</p> <p>Speckle tracking is a feasible technique for the assessment of longitudinal myocardial LA deformation. Reference ranges of strain indices were reported.</p
A Runaway Black Hole in COSMOS: Gravitational Wave or Slingshot Recoil?
We present a detailed study of a peculiar source in the COSMOS survey at
z=0.359. Source CXOCJ100043.1+020637 (CID-42) presents two compact optical
sources embedded in the same galaxy. The distance between the 2, measured in
the HST/ACS image, is 0.495" that, at the redshift of the source, corresponds
to a projected separation of 2.46 kpc. A large (~1200 km/s) velocity offset
between the narrow and broad components of Hbeta has been measured in three
different optical spectra from the VLT/VIMOS and Magellan/IMACS instruments.
CID-42 is also the only X-ray source having in its X-ray spectra a strong
redshifted broad absorption iron line, and an iron emission line, drawing an
inverted P-Cygni profile. The Chandra and XMM data show that the absorption
line is variable in energy by 500 eV over 4 years and that the absorber has to
be highly ionized, in order not to leave a signature in the soft X-ray
spectrum. That these features occur in the same source is unlikely to be a
coincidence. We envisage two possible explanations: (1) a gravitational wave
recoiling black hole (BH), caught 1-10 Myr after merging, (2) a Type 1/ Type 2
system in the same galaxy where the Type 1 is recoiling due to slingshot effect
produced by a triple BH system. The first possibility gives us a candidate
gravitational waves recoiling BH with both spectroscopic and imaging
signatures. In the second case, the X-ray absorption line can be explained as a
BAL-like outflow from the foreground nucleus (a Type 2 AGN) at the rearer one
(a Type 1 AGN), which illuminates the otherwise undetectable wind, giving us
the first opportunity to show that fast winds are present in obscured AGN.Comment: 13 figures; submitted to ApJ. Sent back to the referee after the
first interaction and awaiting the final comment
Menus for Feeding Black Holes
Black holes are the ultimate prisons of the Universe, regions of spacetime
where the enormous gravity prohibits matter or even light to escape to
infinity. Yet, matter falling toward the black holes may shine spectacularly,
generating the strongest source of radiation. These sources provide us with
astrophysical laboratories of extreme physical conditions that cannot be
realized on Earth. This chapter offers a review of the basic menus for feeding
matter onto black holes and discusses their observational implications.Comment: 27 pages. Accepted for publication in Space Science Reviews. Also to
appear in hard cover in the Space Sciences Series of ISSI "The Physics of
Accretion onto Black Holes" (Springer Publisher
On the co-evolution of supermassive black holes and their host galaxies since z = 3
[Abridged] To investigate the evolution in the relation between galaxy
stellar and central black hole mass we construct a volume limited complete
sample of 85 AGN with host galaxy stellar masses M_{*} > 10^{10.5} M_{sol}, and
specific X-ray luminosities L_{X} > 2.35 x 10^{43} erg s^{-1} at 0.4 < z < 3.
We calculate the Eddington limiting masses of the supermassive black holes
residing at the centre of these galaxies, and observe an increase in the
average Eddington limiting black hole mass with redshift. By assuming that
there is no evolution in the Eddington ratio (\mu) and then that there is
maximum possible evolution to the Eddington limit, we quantify the maximum
possible evolution in the M_{*} / M_{BH} ratio as lying in the range 700 <
M_{*}/M_{BH} < 10000, compared with the local value of M_{*}/M_{BH} ~ 1000. We
furthermore find that the fraction of galaxies which are AGN (with L_{X} > 2.35
x 10^{43} erg s^{-1}) rises with redshift from 1.2 +/- 0.2 % at z = 0.7 to 7.4
+/- 2.0 % at z = 2.5. We use our results to calculate the maximum timescales
for which our sample of AGN can continue to accrete at their observed rates
before surpassing the local galaxy-black hole mass relation. We use these
timescales to calculate the total fraction of massive galaxies which will be
active (with L_{X} > 2.35 x 10^{43} erg s^{-1}) since z = 3, finding that at
least ~ 40% of all massive galaxies will be Seyfert luminosity AGN or brighter
during this epoch. Further, we calculate the energy density due to AGN activity
in the Universe as 1.0 (+/- 0.3) x 10^{57} erg Mpc^{-3} Gyr^{-1}, potentially
providing a significant source of energy for AGN feedback on star formation. We
also use this method to compute the evolution in the X-ray luminosity density
of AGN with redshift, finding that massive galaxy Seyfert luminosity AGN are
the dominant source of X-ray emission in the Universe at z < 3.Comment: 25 pages, 10 figures, accepted for publication in MNRA
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