189 research outputs found
Black Hole Astrophysics in AdS Braneworlds
We consider astrophysics of large black holes localized on the brane in the
infinite Randall-Sundrum model. Using their description in terms of a conformal
field theory (CFT) coupled to gravity, deduced in Ref. [1], we show that they
undergo a period of rapid decay via Hawking radiation of CFT modes. For
example, a black hole of mass would shed most of its
mass in years if the AdS radius is mm,
currently the upper bound from table-top experiments. Since this is within the
mass range of X-ray binary systems containing a black hole, the evaporation
enhanced by the hidden sector CFT modes could cause the disappearance of X-ray
sources on the sky. This would be a striking signature of RS2 with a large AdS
radius. Alternatively, for shorter AdS radii, the evaporation would be slower.
In such cases, the persistence of X-ray binaries with black holes already
implies an upper bound on the AdS radius of L \la 10^{-2} mm, an order of
magnitude better than the bounds from table-top experiments. The observation of
primordial black holes with a mass in the MACHO range and an age comparable to the age of the universe would further
strengthen the bound on the AdS radius to L \la {\rm few} \times 10^{-6} mm.Comment: 14 pages, latex, no figures v2: added reference
Production of H and H with the (K,) reaction
The production of neutron rich -hypernuclei via the
(,) reaction has been studied using data collected with the
FINUDA spectrometer at the DANE -factory (LNF). The analysis of the
inclusive momentum spectra is presented and an upper limit for the
production of H and H from Li and Li, is
assessed for the first time.Comment: 11 pages, 3 figures. Accepted for publication in PL
Baryon polarization in low-energy unpolarized meson-baryon scattering
We compute the polarization of the final-state baryon, in its rest frame, in
low-energy meson--baryon scattering with unpolarized initial state, in
Unitarized BChPT. Free parameters are determined by fitting total and
differential cross-section data (and spin-asymmetry or polarization data if
available) for , and scattering. We also compare our
results with those of leading-order BChPT
Correlated pairs from the reaction
Correlated pairs emitted after the absorption of negative kaons
at rest in light nuclei and are
studied. -hyperons and deuterons are found to be preferentially
emitted in opposite directions. The invariant mass spectrum of
shows a bump whose mass is 32516 MeV/c. The bump mass (binding
energy), width and yield are reported. The appearance of a bump is discussed in
the realm of the [] clustering process in nuclei. The experiment was
performed with the FINUDA spectrometer at DANE (LNF).Comment: 13 pages, 5 figures, accepted for publication in Phys. Lett.
DN interaction from meson exchange
A model of the DN interaction is presented which is developed in close
analogy to the meson-exchange KbarN potential of the Juelich group utilizing
SU(4) symmetry constraints. The main ingredients of the interaction are
provided by vector meson (rho, omega) exchange and higher-order box diagrams
involving D*N, D\Delta, and D*\Delta intermediate states. The coupling of DN to
the pi-Lambda_c and pi-Sigma_c channels is taken into account. The interaction
model generates the Lambda_c(2595) resonance dynamically as a DN quasi-bound
state. Results for DN total and differential cross sections are presented and
compared with predictions of an interaction model that is based on the
leading-order Weinberg-Tomozawa term. Some features of the Lambda_c(2595)
resonance are discussed and the role of the near-by pi-Sigma_c threshold is
emphasized. Selected predictions of the orginal KbarN model are reported too.
Specifically, it is pointed out that the model generates two poles in the
partial wave corresponding to the Lambda(1405) resonance.Comment: 14 pages, 8 figure
A Systemic Approach to Multi-Party Relationship Modeling
Socio-economic systems exist in a wide variety of activity domains and are composed of multiple stakeholder groups. These groups pursue objectives which are often entirely motivated from within their local context. Domain specificities in the form of institutional design, for example the deregulation of Public Utility systems, can further fragment this context. Nevertheless, for these systems to be viable, a management subsystem that maintains a holistic view of the system is required. From a Systems perspective, this highlights the need to invest in methods that capture the interactions between the different stakeholders of the system. It is the understanding of the individual interactions that can help piece together a holistic view of the system thereby enabling system level discourse. In this paper we present a modeling technique that models industry interactions as a multi-party value realization process and takes a Systems approach in analyzing them. Every interaction is analyzed both from outside – system as a black box and from within – system as a white box. The design patterns that emerge from this whole/composite view of value realization provide the necessary foundation to analyze the working of multi-stakeholder systems. An explicit specification of these concepts is presented as Regulation Enabling Ontology, REGENT. As an example, we instantiate REGENT for the urban residential electricity market and demonstrate its effectiveness in identifying the requirements for time-based electricity supply systems
Abundances of the elements in the solar system
A review of the abundances and condensation temperatures of the elements and
their nuclides in the solar nebula and in chondritic meteorites. Abundances of
the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New
Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New
York: Springer-Verlag, p. 560-63
First Results on 12Lambda-C production at DAPHNE
Lambda-hypernuclei are produced and studied, with the FINUDA spectrometer,
for the first time at an e+e- collider: DAPHNE, the Frascati phi-factory. The
slow negative kaons from phi(1020) decay are stopped in thin (0.2 g/cm^2)
nuclear targets, and Lambda-hypernuclei formation is detected by measuring the
momentum of the outgoing pi^-. A preliminary analysis on 12Lambda-C shows an
energy resolution of 1.29 MeV FWHM on the hypernuclear levels, the best
obtained so far with magnetic spectrometers at hadron facilities. Capture rates
for the ground state and the excited ones are reported, and compared with
previous experiments.Comment: 15 pages, 5 figures. v2: one reference updated. Accepted for
publication in Phys. Lett.
Identification and Functional Characterization of G6PC2 Coding Variants Influencing Glycemic Traits Define an Effector Transcript at the G6PC2-ABCB11 Locus
Genome wide association studies (GWAS) for fasting glucose (FG) and insulin (FI) have identified common variant signals which explain 4.8% and 1.2% of trait variance, respectively. It is hypothesized that low-frequency and rare variants could contribute substantially to unexplained genetic variance. To test this, we analyzed exome-array data from up to 33,231 non-diabetic individuals of European ancestry. We found exome-wide significant (P<5×10-7) evidence for two loci not previously highlighted by common variant GWAS: GLP1R (p.Ala316Thr, minor allele frequency (MAF)=1.5%) influencing FG levels, and URB2 (p.Glu594Val, MAF = 0.1%) influencing FI levels. Coding variant associations can highlight potential effector genes at (non-coding) GWAS signals. At the G6PC2/ABCB11 locus, we identified multiple coding variants in G6PC2 (p.Val219Leu, p.His177Tyr, and p.Tyr207Ser) influencing FG levels, conditionally independent of each other and the non-coding GWAS signal. In vitro assays demonstrate that these associated coding alleles result in reduced protein abundance via proteasomal degradation, establishing G6PC2 as an effector gene at this locus. Reconciliation of single-variant associations and functional effects was only possible when haplotype phase was considered. In contrast to earlier reports suggesting that, paradoxically, glucose-raising alleles at this locus are protective against type 2 diabetes (T2D), the p.Val219Leu G6PC2 variant displayed a modest but directionally consistent association with T2D risk. Coding variant associations for glycemic traits in GWAS signals highlight PCSK1, RREB1, and ZHX3 as likely effector transcripts. These coding variant association signals do not have a major impact on the trait variance explained, but they do provide valuable biological insights
Materializing digital collecting: an extended view of digital materiality
If digital objects are abundant and ubiquitous, why should consumers pay for, much less collect them? The qualities of digital code present numerous challenges for collecting, yet digital collecting can and does occur. We explore the role of companies in constructing digital consumption objects that encourage and support collecting behaviours, identifying material configuration techniques that materialise these objects as elusive and authentic. Such techniques, we argue, may facilitate those pleasures of collecting otherwise absent in the digital realm. We extend theories of collecting by highlighting the role of objects and the companies that construct them in materialising digital collecting. More broadly, we extend theories of digital materiality by highlighting processes of digital material configuration that occur in the pre-objectification phase of materialisation, acknowledging the role of marketing and design in shaping the qualities exhibited by digital consumption objects and consequently related consumption behaviours and experiences
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