997 research outputs found
Pseudo-gauges and relativistic spin hydrodynamics for interacting Dirac and Proca fields
We present the explicit expressions of different pseudo-gauge transformations
for Dirac and Proca fields considering a general interaction term. The
particular case of the interaction of Dirac and Proca fields with a background
electromagnetic field is also studied. Starting from the quantum kinetic theory
with collisions derived from the Wigner-function formalism for massive spin-1/2
and spin-1 particles, we establish a connection between different pseudo-gauges
and relativistic spin hydrodynamics. The physical implications of the various
decompositions of orbital and spin angular momentum are discussed.Comment: 21 pages, no figure
Quantum kinetic theory with interactions for massive vector bosons
We present a derivation of quantum kinetic theory for massive spin-1
particles from the Wigner-function formalism up to first order in an
-expansion, including a general interaction term. Both local and
nonlocal contributions are computed in a covariant fashion. It is shown that,
up to first order in , the collision term takes the same form as in the
case of spin-1/2 particles.Comment: 22 pages, no figure
Putting a Price Tag on Personal Information - A Literature Review
In the digital age, personal information is claimed to be the new commodity with a rising market demand and profitability for businesses. Simultaneously, people are becoming aware of the value of their personal information while being concerned about their privacy. This increases the demand of direct compensation or protection. In response to the commodification of privacy and the increased demand for compensation, a number of scholars have shed light on the value people assign to their personal information. However, these findings remain controversial as their results differ tremendously due to different research methods and contexts. To address this gap, we conducted a systematic literature review to gain insights into the current research state and to identify further research avenues. By synthesizing and analyzing 37 publications, we provide an integrative framework along with seven contextual factors affecting individuals’ valuation of privacy
Relativistic dissipative spin hydrodynamics from kinetic theory with a nonlocal collision term
We derive relativistic dissipative spin hydrodynamics from kinetic theory
featuring a nonlocal collision term using the method of moments. In this
framework, the components of the spin tensor are dynamical variables which obey
relaxation-type equations. We find that the corresponding relaxation times are
determined by the local part of the collision term, while the nonlocal part
contributes to the Navier-Stokes terms in these equations of motion. The spin
relaxation time scales are comparable to those of the usual dissipative
currents. Finally, the Navier-Stokes limit of the Pauli-Lubanski vector
receives contributions proportional to the shear tensor of the fluid, which
implies that the polarization of hadrons observed in heavy-ion collisions is
influenced by dissipative effects.Comment: 7 pages, 1 figur
What is Your Selfie Worth? A Field Study on Individuals’ Valuation of Personal Data
Referred to as the new oil, undoubtedly personal data is a valuable resource for organizations. Contrary, it is still blurred, to what extent individuals value their data even though, in a digitized world, users are requested to exchange their data for adequate services. Former research on individuals’ valuation of personal data result in scattered, partly contradictious values, depending on the data type, context, and the measurement method. In this study, we aimed to facilitate the valuation for individuals by applying a new and promising measurement methodology: the participants of our field experiment had the chance to sell their selfies in a name-your-own-price auction with repeated bidding and feedback loops. As a result, 39% of our participants were willing to donate or sell their selfies with a median of 5€. Additionally, bidding clusters were identified. Implications for research on the valuation of personal data in terms of privacy are discussed
Mutations in the Lipopolysaccharide Biosynthesis Pathway Interfere with Crescentin-Mediated Cell Curvature in Caulobacter crescentus
Bacterial cell morphogenesis requires coordination among multiple cellular systems, including the bacterial
cytoskeleton and the cell wall. In the vibrioid bacterium Caulobacter crescentus, the intermediate filament-like
protein crescentin forms a cell envelope-associated cytoskeletal structure that controls cell wall growth to
generate cell curvature. We undertook a genetic screen to find other cellular components important for cell
curvature. Here we report that deletion of a gene (wbqL) involved in the lipopolysaccharide (LPS) biosynthesis
pathway abolishes cell curvature. Loss of WbqL function leads to the accumulation of an aberrant Opolysaccharide
species and to the release of the S layer in the culture medium. Epistasis and microscopy
experiments show that neither S-layer nor O-polysaccharide production is required for curved cell morphology
per se but that production of the altered O-polysaccharide species abolishes cell curvature by apparently
interfering with the ability of the crescentin structure to associate with the cell envelope. Our data suggest that
perturbations in a cellular pathway that is itself fully dispensable for cell curvature can cause a disruption of
cell morphogenesis, highlighting the delicate harmony among unrelated cellular systems. Using the wbqL
mutant, we also show that the normal assembly and growth properties of the crescentin structure are
independent of its association with the cell envelope. However, this envelope association is important for
facilitating the local disruption of the stable crescentin structure at the division site during cytokinesis
Discovery of Extended Tidal Tails around the Globular Cluster Palomar 13
We use photometry from the DECam Legacy Survey to detect candidate tidal
tails extending ~5 deg on either side of the Palomar 13 globular cluster. The
tails are aligned with the proper motion of Palomar 13 and are consistent with
its old, metal-poor stellar population. We identify three RR Lyrae stars that
are plausibly associated with the tails, in addition to four previously known
in the cluster. From these RR Lyrae stars, we find that the mean distance to
the cluster and tails is kpc and estimate the total (initial)
luminosity of the cluster to be ,
consistent with previous claims that its initial luminosity was higher than its
current luminosity. Combined with previously-determined proper motion and
radial velocity measurements of the cluster, we find that Palomar 13 is on a
highly eccentric orbit () with a pericenter of ~9 kpc and an
apocenter of ~69 kpc, and a recent pericentric passage of the cluster ~75 Myr
ago. We note a prominent linear structure in the interstellar dust map that
runs parallel to the candidate tidal features, but conclude that reddening due
to dust is unlikely to account for the structure that we observe. If confirmed,
the Palomar 13 stellar stream would be one of very few streams with a known
progenitor system, making it uniquely powerful for studying the disruption of
globular clusters, the formation of the stellar halo, and the distribution of
matter within our Galaxy.Comment: 8 pages, 4 figures, 1 table. Submitted to AAS journal
Prepackaged central line kits reduce procedural mistakes during central line insertion: a randomized controlled prospective trial
BACKGROUND: Central line catheter insertion is a complex procedure with a high cognitive load for novices. Providing a prepackaged all-inclusive kit is a simple measure that may reduce the cognitive load. We assessed whether the use of prepackaged all-inclusive central line insertion kits reduces procedural mistakes during central line catheter insertion by novices. METHODS: Thirty final year medical students and recently qualified physicians were randomized into two equal groups. One group used a prepackaged all-inclusive kit and the other used a standard kit containing only the central vein catheter and all other separately packaged components provided in a materials cart. The procedure was videotaped and analyzed by two blinded raters using a checklist. Both groups performed central line catheter insertion on a manikin, assisted by nursing students. RESULTS: The prepackaged kit group outperformed the standard kit group in four of the five quality indicators: procedure duration (26:26 ± 3:50 min vs. 31:27 ± 5:57 min, p = .01); major technical mistakes (3.1 ± 1.4 vs. 4.8 ± 2.6, p = .03); minor technical mistakes (5.2 ± 1.7 vs. 8.0 ± 3.2, p = .01); and correct steps (83 ± 5% vs. 75 ± 11%, p = .02). The difference for breaches of aseptic technique (1.2 ± 0.8 vs. 3.0 ± 3.6, p = .06) was not statistically significant. CONCLUSIONS: Prepackaged all-inclusive kits for novices improved the procedure quality and saved staff time resources in a controlled simulation environment. Future studies are needed to address whether central line kits also improve patient safety in hospital settings
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