Thanks to the exceptional development of high power femtosecond lasers in the last 15years, Compton based X-ray sources are in full development over the world in the recent years. Compact Compton ...sources are able to combine the compactness of the instrument with a beam of high intensity, high quality, tunable in energy. In various fields of applications such as biomedical science, cultural heritage preservation and material science researches, these sources should provide an easy working environment and the methods currently used at synchrotrons could be largely developed in a lab-size environment as hospitals, labs, or museums.
Vacuum quantum fluctuations near horizons are known to yield correlated emission by the Hawking effect. We use a driven-dissipative quantum fluid of microcavity polaritons as an analog model of a ...quantum field theory on a black-hole spacetime and numerically calculate correlated emission. We show that, in addition to the Hawking effect at the sonic horizon, quantum fluctuations may result in a sizable stationary excitation of a quasinormal mode of the field theory. Observable signatures of the excitation of the quasinormal mode are found in the spatial density fluctuations as well as in the spectrum of Hawking emission. This suggests an intrinsic fluctuation-driven mechanism leading to the quantum excitation of quasinormal modes on black hole spacetimes.
The next generation of analogue gravity experiments Jacquet, M. J.; Weinfurtner, S.; König, F.
Philosophical transactions - Royal Society. Mathematical, Physical and engineering sciences/Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences,
08/2020, Letnik:
378, Številka:
2177
Journal Article
Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant ...vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg −/+ and HBeAg −/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0‐1‐2‐12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti‐HBs antibodies and serological markers of hepatitis B infection (anti‐HBc, HBsAg, and in selected cases HBeAg, anti‐HBe, HBV DNA). During the 20‐year follow‐up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti‐HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 12.2%). During the second decade, breakthrough HBV infections were detected in all groups (18/140 12.8%). Increases in anti‐HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long‐term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure. (http://www.clinicaltrials.gov NCT00240500 and NCT00456625)
Mineral dust deposition is an important supply mechanism for trace elements in the low-latitude ocean. Our understanding of the controls of such inputs has been mostly built on laboratory and surface ...ocean studies. The lack of direct observations and the tendency to focus on near-surface waters prevent a comprehensive evaluation of the role of dust in oceanic biogeochemical cycles. In the frame of the PEACETIME project (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea), the responses of the aluminum (Al) and iron (Fe) cycles to two dust wet deposition events over the central and western Mediterranean Sea were investigated at a timescale of hours to days using a comprehensive dataset gathering dissolved and suspended particulate concentrations, along with sinking fluxes.
The fossil record of the terminal Ediacaran Period is typified by the iconic index fossil Cloudina and its relatives. These tube-dwellers are presumed to be primitive metazoans, but resolving their ...phylogenetic identity has remained a point of contention. The root of the problem is a lack of diagnostic features; that is, phylogenetic interpretations have largely centered on the only available source of information-their external tubes. Here, using tomographic analyses of fossils from the Wood Canyon Formation (Nevada, USA), we report evidence of recognizable soft tissues within their external tubes. Although alternative interpretations are plausible, these internal cylindrical structures may be most appropriately interpreted as digestive tracts, which would be, to date, the earliest-known occurrence of such features in the fossil record. If this interpretation is correct, their nature as one-way through-guts not only provides evidence for establishing these fossils as definitive bilaterians but also has implications for the long-debated phylogenetic position of the broader cloudinomorphs.
In the ocean, remineralization rate associated with sinking particles is a
crucial variable. Since the 1990s, particulate biogenic barium (Baxs) has been used as an indicator of carbon ...remineralization by applying a transfer function relating Baxs to O2 consumption (Dehairs's
transfer function, Southern Ocean-based). Here, we tested its validity in
the Mediterranean Sea (ANTARES/EMSO-LO) for the first time by investigating connections between Baxs, prokaryotic heterotrophic
production (PHP) and oxygen consumption (JO2-Opt; optodes measurement). We show that (1) higher Baxs (409 pM; 100–500 m) occurs in situations where integrated PHP (PHP100/500=0.90) is located deeper, (2) higher Baxs occurs with increasing JO2-Opt, and (3) there is similar magnitude between JO2-Opt (3.14 mmol m−2 d−1; 175–450 m) and JO2-Ba (4.59 mmol m−2 d−1; transfer function). Overall,
Baxs, PHP and JO2 relationships follow trends observed earlier in the Southern Ocean. We conclude that such a transfer function could apply in the Mediterranean Sea.
We report on the sub-basin variability in particulate organic carbon (POC)
remineralization in the western and central Mediterranean Sea in late spring
during the PEACETIME (ProcEss studies at the
...Air–sEa Interface after dust deposition in the MEditerranean sea) cruise. POC remineralization rates were estimated using
the excess biogenic particulate barium (Baxs) inventories in the
mesopelagic layers (100–1000 m depth) and compared with prokaryotic
heterotrophic production (PHP). Baxs-based mesopelagic remineralization
rates (MRs) ranged from 25±2 to 306±70 mgCm-2d-1.
MRs were larger in the Algero-Provençal (ALG) Basin than in the
Tyrrhenian (TYR) and Ionian (ION) basins. Our Baxs inventories and
integrated PHP data also indicated that significant mesopelagic
remineralization occurred down to 1000 m depth in the ALG Basin in contrast
to the ION and TYR basins, where remineralization was mainly located above
500 m depth. We propose that the higher and deeper MRs in the ALG
Basin were sustained by an additional particle export event driven by deep
convection. The TYR Basin (in contrast to the ALG and ION basins) presented
the impact of a previous dust event, as reflected by our particulate Al water
column concentrations. The ION and TYR basins showed small-scale
heterogeneity in remineralization processes, reflected by our Baxs
inventories and integrated PHP data at the Tyrr long-duration station.
This heterogeneity was linked to the mosaic of blooming and non-blooming
patches reported in this area during the cruise. In contrast to the western
Mediterranean Sea (ALG Basin), the central Mediterranean Sea (ION and TYR
basins) showed lower remineralization rates restricted to the upper
mesopelagic layer during the late spring PEACETIME cruise.
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