71 research outputs found
Transmission phase of a quantum dot and statistical fluctuations of partial-width amplitudes
Experimentally, the phase of the amplitude for electron transmission through
a quantum dot (transmission phase) shows the same pattern between consecutive
resonances. Such universal behavior, found for long sequences of resonances, is
caused by correlations of the signs of the partial-width amplitudes of the
resonances. We investigate the stability of these correlations in terms of a
statistical model. For a classically chaotic dot, the resonance eigenfunctions
are assumed to be Gaussian distributed. Under this hypothesis, statistical
fluctuations are found to reduce the tendency towards universal phase
evolution. Long sequences of resonances with universal behavior only persist in
the semiclassical limit of very large electron numbers in the dot and for
specific energy intervals. Numerical calculations qualitatively agree with the
statistical model but quantitatively are closer to universality.Comment: 8 pages, 4 figure
Association of Perioperative Regional Analgesia with Postoperative Patient-Reported Pain Outcomes and Opioid Requirements: Comparing 22 Different Surgical Groups in 23,911 Patients from the QUIPS Registry
(1) Background: In many surgical procedures, regional analgesia (RA) techniques are
associated with improved postoperative analgesia compared to systemic pain treatment. As continuous RA requires time and experienced staff, it would be helpful to identify settings in which
continuous RA has the largest benefit. (2) Methods: On the basis of 23,911 data sets from 179 German
and Austrian hospitals, we analyzed the association of perioperative RA with patient-reported pain
intensity, functional impairment of movement, nausea and opioid use for different surgeries. Regression analyses adjusted for age, sex and preoperative pain were performed for each surgery and the
following groups: patients receiving continuous RA (surgery and ward; RA++), RA for surgery only
(RA+−) and patients receiving no RA (RA−−). (3) Results: Lower pain scores in the RA++ compared
to the RA−− group were observed in 13 out of 22 surgeries. There was no surgery where pain scores
for RA++ were higher than for RA−−. If maximal pain, function and side effects were combined, the
largest benefit of continuous RA (RA++) was observed in laparoscopic colon and sigmoid surgery,
ankle joint arthrodesis, revision (but not primary) surgery of hip replacement, open nephrectomy and
shoulder surgery. The benefit of RA+− was lower than that of RA++. (4) Discussion: The additional
benefit of RA for the mentioned surgeries is larger than in many other surgeries in clinical routine.
The decision to use RA in a given surgery should be based on the expected pain intensity without
RA and its additional benefits
Properties of low-lying states in a diffusive quantum dot and Fock-space localization
Motivated by an experiment by Sivan et al. (Europhys. Lett. 25, 605 (1994))
and by subsequent theoretical work on localization in Fock space, we study
numerically a hierarchical model for a finite many-body system of Fermions
moving in a disordered potential and coupled by a two-body interaction. We
focus attention on the low-lying states close to the Fermi energy. Both the
spreading width and the participation number depend smoothly on excitation
energy. This behavior is in keeping with naive expectations and does not
display Anderson localization. We show that the model reproduces essential
features of the experiment by Sivan et al.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let
Galectin-3 Induces a Pro-degradative/inflammatory Gene Signature in Human Chondrocytes, Teaming Up with Galectin-1 in Osteoarthritis Pathogenesis
Inflammatory chemo-and cytokines and matrix-degrading proteases underlie the progression of osteoarthritis (OA). Aiming to define upstream regulators for these disease markers, we pursued initial evidence for an upregulation of members of the adhesion/growth-regulatory galectin family. Immunohistochemical localization of galectin-3 (Gal-3) in sections of human cartilage with increasing levels of degeneration revealed a linear correlation reaching a chondrocyte positivity of 60%. Presence in situ was cytoplasmic, the lectin was secreted from OA chondrocytes in culture and binding of Gal-3 yielded lactose-inhibitable surface staining. Exposure of cells to the lectin led to enhanced gene expression and secretion of functional disease markers. Genome-wide transcriptomic analysis broadened this result to reveal a pro-degradative/inflammatory gene signature under the control of NF-kappa B. Fittingly, targeting this route of activation by inhibitors impaired the unfavourable response to Gal-3 binding, as also seen by shortening the lectin's collagen-like repeat region. Gal-3's activation profile overlaps with that of homodimeric galectin-1 (Gal-1) and also has distinctive (supplementing) features. Tested at subsaturating concentrations in a mixture, we found cooperation between the two galectins, apparently able to team up to promote OA pathogenesis. In summary, our results suggest that a network of endogenous lectins is relevant for initiating this process cascade
What turns galaxies off? The different morphologies of star-forming and quiescent galaxies since z~2 from CANDELS
We use HST/WFC3 imaging from the CANDELS Multicycle Treasury Survey, in
conjunction with the Sloan Digital Sky Survey, to explore the evolution of
galactic structure for galaxies with stellar masses >3e10M_sun from z=2.2 to
the present epoch, a time span of 10Gyr. We explore the relationship between
rest-frame optical color, stellar mass, star formation activity and galaxy
structure. We confirm the dramatic increase from z=2.2 to the present day in
the number density of non-star-forming galaxies above 3e10M_sun reported by
others. We further find that the vast majority of these quiescent systems have
concentrated light profiles, as parametrized by the Sersic index, and the
population of concentrated galaxies grows similarly rapidly. We examine the
joint distribution of star formation activity, Sersic index, stellar mass,
inferred velocity dispersion, and stellar surface density. Quiescence
correlates poorly with stellar mass at all z<2.2. Quiescence correlates well
with Sersic index at all redshifts. Quiescence correlates well with `velocity
dispersion' and stellar surface density at z>1.3, and somewhat less well at
lower redshifts. Yet, there is significant scatter between quiescence and
galaxy structure: while the vast majority of quiescent galaxies have prominent
bulges, many of them have significant disks, and a number of bulge-dominated
galaxies have significant star formation. Noting the rarity of quiescent
galaxies without prominent bulges, we argue that a prominent bulge (and
perhaps, by association, a supermassive black hole) is an important condition
for quenching star formation on galactic scales over the last 10Gyr, in
qualitative agreement with the AGN feedback paradigm.Comment: The Astrophysical Journal, in press; 20 pages with 13 figure
The MOBI-Kids Study Protocol: Challenges in Assessing Childhood and Adolescent Exposure to Electromagnetic Fields from Wireless Telecommunication Technologies and Possible Association with Brain Tumor Risk
The rapid increase in mobile phone use in young people has generated concern about possible health effects of exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF). MOBI-Kids, a multinational case-control study, investigates the potential effects of childhood and adolescent exposure to EMF from mobile communications technologies on brain tumor risk in 14 countries. The study, which aims to include approximately 1,000 brain tumor cases aged 10-24 years and two individually matched controls for each case, follows a common protocol and builds upon the methodological experience of the INTERPHONE study. The design and conduct of a study on EMF exposure and brain tumor risk in young people in a large number of countries is complex and poses methodological challenges. This manuscript discusses the design of MOBI-Kids and describes the challenges and approaches chosen to address them, including: (1) the choice of controls operated for suspected appendicitis, to reduce potential selection bias related to low response rates among population controls; (2) investigating a young study population spanning a relatively wide age range; (3) conducting a large, multinational epidemiological study, while adhering to increasingly stricter ethics requirements; (4) investigating a rare and potentially fatal disease; and (5) assessing exposure to EMF from communication technologies. Our experience in thus far developing and implementing the study protocol indicates that MOBI-Kids is feasible and will generate results that will contribute to the understanding of potential brain tumor risks associated with use of mobile phones and other wireless communications technologies among young people
Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank
9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved:
the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded
signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other
chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and
Conselleria de Pesca de la Xunta de GaliciaPeer reviewe
The James Webb Space Telescope
The James Webb Space Telescope (JWST) is a large (6.6m), cold (50K),
infrared-optimized space observatory that will be launched early in the next
decade. The observatory will have four instruments: a near-infrared camera, a
near-infrared multi-object spectrograph, and a tunable filter imager will cover
the wavelength range, 0.6 to 5.0 microns, while the mid-infrared instrument
will do both imaging and spectroscopy from 5.0 to 29 microns. The JWST science
goals are divided into four themes. The End of the Dark Ages: First Light and
Reionization theme seeks to identify the first luminous sources to form and to
determine the ionization history of the early universe. The Assembly of
Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars,
metals, morphological structures, and active nuclei within them evolved from
the epoch of reionization to the present day. The Birth of Stars and
Protoplanetary Systems theme seeks to unravel the birth and early evolution of
stars, from infall on to dust-enshrouded protostars to the genesis of planetary
systems. The Planetary Systems and the Origins of Life theme seeks to determine
the physical and chemical properties of planetary systems including our own,
and investigate the potential for the origins of life in those systems. To
enable these observations, JWST consists of a telescope, an instrument package,
a spacecraft and a sunshield. The telescope consists of 18 beryllium segments,
some of which are deployed. The segments will be brought into optical alignment
on-orbit through a process of periodic wavefront sensing and control. The JWST
operations plan is based on that used for previous space observatories, and the
majority of JWST observing time will be allocated to the international
astronomical community through annual peer-reviewed proposal opportunities.Comment: 96 pages, including 48 figures and 15 tables, accepted by Space
Science Review
Hans Weinmann Collection.
Questionnaire I + II of the Austrian Heritage Collection at the Leo Baeck Institute; student ID (1936); street car pass (1939); 2 school certificates; legal papers; Letter from Gustav Weinmann (Hans Weinmann's father) to Nazi officials.Hans Weinmann, 1999AHC questionnaire and various school certificates and legal correspondence // 1926-1999Born in Vienna in 1926. Fled to England with Kindertransport. Emigrated to the U.S. in 1940.Austrian Heritage Collectiondigitize
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