82 research outputs found
Integration by parts formula for locally smooth laws and applications to sensitivity computations
We consider random variables of the form , where is a
smooth function and , are random variables with absolutely
continuous law . We assume that , , are piecewise
differentiable and we develop a differential calculus of Malliavin type based
on . This allows us to establish an integration by parts
formula , where is a
random variable constructed using the differential operators acting on and
We use this formula in order to give numerical algorithms for sensitivity
computations in a model driven by a L\'{e}vy process.Comment: Published at http://dx.doi.org/10.1214/105051606000000592 in the
Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute
of Mathematical Statistics (http://www.imstat.org
Hivatali eskĂŒ a magyar közszolgĂĄlatban
This study proposes an archaeology of the official oath in the royal Hungarian administration, from the first centuries of the Christian statehood to the end of the monarchy in 1918. The evolutions of the oath pronounced by the councilors (in various medieval councils, dicastries and later in the 19th centuryâs ministries) allows replacing in the longue durĂ©e this complex phenomenon, the persistence of which until today shows a remarkably long-lasting tradition. First to be addressed here is the issue of implementing a mandatory oath for the kingâs and later the stateâs servants, crystallizing the bureaucratization and professionalization of the administration. The second issue is specific to the 19th and 20th centuries, and focuses on the multiple reformulations of official oaths during revolutionary periods: how did evolve the duty of loyalty between allegiance to the king, the constitution, the country and finally the nation? In order to achieve this study, oath-templates were collected from various official sources (Corpus Juris Hungarici, Rendeletek TĂĄra) as well as from archival oath-repositories (libri juramentorum). The political as well as ritual dimensions of the oath taking (and its refusal) are just incidentally part of our study
Systematic error and comparison of four methods for assessing the viability ofSaccharomyces cerevisiae suspensions
Four methods for the determination of cell viability were compared: the plate count technique, the flow cytometer, and two microscopic numerations- one after methylene blue staining and the other one with epifluorescence. The experimental error of these techniques was for the first time estimated: 8% for both numerations under microscope and 13% for the plate count technique. The staining mechanisms were explained by comparing the numerations under microscope and the flow cytometer analysis
Correlated Anisotropies in the Cosmic Far-Infrared Background Detected by MIPS/Spitzer: Constraint on the Bias
We report the detection of correlated anisotropies in the Cosmic Far-Infrared
Background at 160 microns. We measure the power spectrum in the Spitzer/SWIRE
Lockman Hole field. It reveals unambiguously a strong excess above cirrus and
Poisson contributions, at spatial scales between 5 and 30 arcminutes,
interpreted as the signature of infrared galaxy clustering. Using our model of
infrared galaxy evolution we derive a linear bias b=1.74 \pm 0.16. It is a
factor 2 higher than the bias measured for the local IRAS galaxies. Our model
indicates that galaxies dominating the 160 microns correlated anisotropies are
at z~1. This implies that infrared galaxies at high redshifts are biased
tracers of mass, unlike in the local Universe.Comment: ApJ Letters, in pres
The infrared luminosity function of galaxies at redshifts z=1 and z~2 in the GOODS fields
We present the rest-frame 8 micron luminosity function (LF) at redshifts z=1
and ~2, computed from Spitzer 24 micron-selected galaxies in the GOODS fields
over an area of 291 sq. arcmin. Using classification criteria based on X-ray
data and IRAC colours, we identify the AGN in our sample. The rest-frame 8
micron LF for star-forming galaxies at redshifts z=1 and ~2 have the same shape
as at z~0, but with a strong positive luminosity evolution. The number density
of star-forming galaxies with log_{10}(nu L_nu(8 micron))>11 increases by a
factor >250 from redshift z~0 to 1, and is basically the same at z=1 and ~2.
The resulting rest-frame 8 micron luminosity densities associated with star
formation at z=1 and ~2 are more than four and two times larger than at z~0,
respectively. We also compute the total rest-frame 8 micron LF for star-forming
galaxies and AGN at z~2 and show that AGN dominate its bright end, which is
well-described by a power-law. Using a new calibration based on Spitzer
star-forming galaxies at 0<z<0.6 and validated at higher redshifts through
stacking analysis, we compute the bolometric infrared (IR) LF for star-forming
galaxies at z=1 and ~2. We find that the respective bolometric IR luminosity
densities are (1.2+/-0.2) x 10^9 and (6.6^{+1.2}_{-1.0}) x 10^8 L_sun Mpc^{-3},
in agreement with previous studies within the error bars. At z~2, around 90% of
the IR luminosity density associated with star formation is produced by
luminous and ultraluminous IR galaxies (LIRG and ULIRG), with the two
populations contributing in roughly similar amounts. Finally, we discuss the
consistency of our findings with other existing observational results on galaxy
evolution.Comment: Accepted for publication in the ApJ. 33 pages, 15 figures. Uses
emulateap
Integration by parts formula for locally smooth laws and applications to sensitivity computations
We consider random variables of the form where is a smooth function and V_i,i\in\mathbbN are random variables with absolutely continuous law We assume that are piecewise differentiable and we develop a differential calculus of Malliavin type based on \partial\lnp_i. This allows us to establish an integration by parts formula where is a random variable constructed using the differential operators acting on and We use this formula in order to give numerical algorithms for sensitivity computations in a model driven by a LĂ©vy process
Soft band X/K luminosity ratios in late-type galaxies and constraints on the population of supersoft X-ray sources
We study X-ray to K-band luminosity ratios (L_X/L_K) of late-type galaxies in
the 0.3-0.7 keV energy range. From the Chandra archive, we selected nine spiral
and three irregular galaxies with point source detection sensitivity better
than 5 x 10^36 erg/s in order to minimize the contribution of unresolved X-ray
binaries. In late-type galaxies cold gas and dust may cause significant
interstellar absorption, therefore we also demanded the existence of publicly
available HI maps. The obtained L_X/L_K ratios vary between (5.4-68) x 10^27
erg/s/L_K,sun exceeding by factor of 2-20 the values obtained for gas-poor
early-type galaxies. Based on these results we constrain the role of supersoft
X-ray sources as progenitors of type Ia supernovae (SNe Ia). For majority of
galaxies the upper limits range from ~3% to ~15% of the SN Ia frequency
inferred from K-band luminosity, but for a few of them no meaningful
constraints can be placed. On a more detailed level, we study individual
structural components of spiral galaxies: bulge and disk, and, for grand design
spiral galaxies, arm and interarm regions.Comment: 10 pages, 2 tables, 6 figures, accepted for publication in MNRAS,
minor change
Air pressure effects on biomass yield of two different Kluyveromyces strains
The use of air pressure as a way of improving oxygen transfer in aerobic bioreactors was investigated. To compare the air pressure effects
with traditional air bubbled cultures, experiments using a pressure reactor and a stirred flask, with the same oxygen transfer rate, were made.
Kluyveromyces marxianus is an important industrial yeast and some of it show a âKluyver effectâ for lactose: even under oxygen limited
growth conditions, certain disaccharides that support aerobic, respiratory growth, are not fermented. This study deals with the effect of
increased pressure on the physiological behavior of two Kluyveromyces strains: K. marxianus ATCC10022 is a lactose-fermenting strain,
whereas K. marxianus CBS 7894 has a Kluyver-effect for lactose. For K. marxianus ATCC10022 an air pressure increase of 2 bar led to
a 3-fold increase in biomass yield. When air pressure increased an enhancement of ethanol oxidation of cell yeasts was also observed. Batch
cultures of K. marxianus CBS 7894 exhibited different growth behaviour. Its metabolism was always oxidative and ethanol was never
produced. With the increase in air pressure, it was possible to increase the productivity in biomass of K. marxianus CBS 7894. As a response
to high oxygen concentrations, due to the increase in oxygen partial pressure, oxidative stress in the cells was also studied. Antioxidant
defences, such as superoxide dismutase, catalase, and glutathione reductase, were at high activity levels, suggesting that these yeast strains
could tolerate the increased pressures applied.Fundação para a CiĂȘncia e a Tecnologia (FCT) â PRAXIS XXI
The Environments of Local Luminous Infrared Galaxies: Star Formation Rates increase with Density
This work studies the environments and star formation relationships of local
luminous infrared galaxies (LIRG) in comparison to other types of local and
distant (z~1) galaxies. The infrared (IR) galaxies are drawn from the IRAS
sample. The density of the environment is quantified using 6dF and Point Source
Catalogue redshift survey (PSCz) galaxies in a cylinder of 2h^-1 Mpc radius and
10h^-1 Mpc length. Our most important result shows the existence of a dramatic
density difference between local LIRGs and local non-LIRG IR galaxies. LIRGs
live in denser environments than non-LIRG IR galaxies implying that L_IR=10^11
h^-2 L_sun marks an important transition point among IR-selected local
galaxies. We also find that there is a strong correlation between the densities
around LIRGs and their L_IR luminosity, while the IR-activity of non-LIRG IR
galaxies does not show any dependence on environment. This trend is independent
of mass-bin selection. The SF-density trend in local LIRGs is similar to that
found in some studies of blue cloud galaxies at z~1 which show a correlation
between star formation and local density (the reversal of the relation seen for
local galaxies). This, together with the rapid decline of the number count of
LIRGs since z~1, could mean that local LIRGs are survivors of whatever process
transformed blue cloud galaxies at z~1 to the present day or local LIRGs came
into existence by similar process than high redshift LIRGs but at later stage.Comment: 13 pages with 6 figures. Discussion expanded and references added to
match accepted MNRAS version, results unchange
Environmental dependence of 8um luminosity functions of galaxies at z~0.8: Comparison between RXJ1716.4+6708 and the AKARI NEP deep field
We aim to reveal environmental dependence of infrared luminosity functions
(IR LFs) of galaxies at z~0.8 using the AKARI satellite. We construct restframe
8um IR LFs in the cluster region RXJ1716.4+6708 at z=0.81, and compare them
with a blank field using the AKARI North Ecliptic Pole deep field data at the
same redshift. AKARI's wide field of view (10'x10') is suitable to investigate
wide range of galaxy environments. AKARI's 15um filter is advantageous here
since it directly probes restframe 8um at z~0.8, without relying on a large
extrapolation based on a SED fit, which was the largest uncertainty in previous
work. We have found that cluster IR LFs at restframe 8um have a factor of 2.4
smaller L^* and a steeper faint-end slope than that of the field. Confirming
this trend, we also found that faint-end slopes of the cluster LFs becomes
flatter and flatter with decreasing local galaxy density. These changes in LFs
cannot be explained by a simple infall of field galaxy population into a
cluster. Physics that can preferentially suppress IR luminous galaxies in high
density regions is required to explain the observed results.Comment: Accepted for publication in A&A AKARI special issu
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