131 research outputs found
Minimal Gaugomaly Mediation
Mixed anomaly and gauge mediation ("gaugomaly'' mediation) gives a natural
solution to the SUSY flavor problem with a conventional LSP dark matter
candidate. We present a minimal version of gaugomaly mediation where the
messenger masses arise directly from anomaly mediation, automatically
generating a messenger scale of order 50 TeV. We also describe a simple
relaxation mechanism that gives rise to realistic mu and B mu terms. B is
naturally dominated by the anomaly-mediated contribution from top loops, so the
mu/B mu sector only depends on a single new parameter. In the minimal version
of this scenario the full SUSY spectrum is determined by two continuous
parameters (the anomaly- and gauge-mediated SUSY breaking masses) and one
discrete parameter (the number of messengers). We show that these simple models
can give realistic spectra with viable dark matter.Comment: 18 pages, 4 figures; v2: corrected example generating non-holomorphic
Kahler term
Constraints on the pMSSM from LAT Observations of Dwarf Spheroidal Galaxies
We examine the ability for the Large Area Telescope (LAT) to constrain
Minimal Supersymmetric Standard Model (MSSM) dark matter through a combined
analysis of Milky Way dwarf spheroidal galaxies. We examine the Lightest
Supersymmetric Particles (LSPs) for a set of ~71k experimentally valid
supersymmetric models derived from the phenomenological-MSSM (pMSSM). We find
that none of these models can be excluded at 95% confidence by the current
analysis; nevertheless, many lie within the predicted reach of future LAT
analyses. With two years of data, we find that the LAT is currently most
sensitive to light LSPs (m_LSP < 50 GeV) annihilating into tau-pairs and
heavier LSPs annihilating into b-bbar. Additionally, we find that future LAT
analyses will be able to probe some LSPs that form a sub-dominant component of
dark matter. We directly compare the LAT results to direct detection
experiments and show the complementarity of these search methods.Comment: 24 pages, 9 figures, submitted to JCA
Loss of the Putative Catalytic Domain of HDAC4 Leads to Reduced Thermal Nociception and Seizures while Allowing Normal Bone Development
Histone deacetylase 4 (HDAC4) has been associated with muscle & bone development [1]β[6]. N-terminal MEF2 and RUNX2 binding domains of HDAC4 have been shown to mediate these effects in vitro. A complete gene knockout has been reported to result in premature ossification and associated defects resulting in postnatal lethality [6]. We report a viral insertion mutation that deletes the putative deacetylase domain, while preserving the N-terminal portion of the protein. Western blot and immuno-precipitation analysis confirm expression of truncated HDAC4 containing N-terminal amino acids 1-747. These mutant mice are viable, living to at least one year of age with no gross defects in muscle or bone. At 2β4 months of age no behavioral or physiological abnormalities were detected except for an increased latency to respond to a thermal nociceptive stimulus. As the mutant mice aged past 5 months, convulsions appeared, often elicited by handling. Our findings confirm the sufficiency of the N-terminal domain for muscle and bone development, while revealing other roles of HDAC4
Intuitionistic implication makes model checking hard
We investigate the complexity of the model checking problem for
intuitionistic and modal propositional logics over transitive Kripke models.
More specific, we consider intuitionistic logic IPC, basic propositional logic
BPL, formal propositional logic FPL, and Jankov's logic KC. We show that the
model checking problem is P-complete for the implicational fragments of all
these intuitionistic logics. For BPL and FPL we reach P-hardness even on the
implicational fragment with only one variable. The same hardness results are
obtained for the strictly implicational fragments of their modal companions.
Moreover, we investigate whether formulas with less variables and additional
connectives make model checking easier. Whereas for variable free formulas
outside of the implicational fragment, FPL model checking is shown to be in
LOGCFL, the problem remains P-complete for BPL.Comment: 29 pages, 10 figure
Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches
The LUX-ZEPLIN (LZ) experiment will search for dark matter particle
interactions with a detector containing a total of 10 tonnes of liquid xenon
within a double-vessel cryostat. The large mass and proximity of the cryostat
to the active detector volume demand the use of material with extremely low
intrinsic radioactivity. We report on the radioassay campaign conducted to
identify suitable metals, the determination of factors limiting radiopure
production, and the selection of titanium for construction of the LZ cryostat
and other detector components. This titanium has been measured with activities
of U~1.6~mBq/kg, U~0.09~mBq/kg,
Th~~mBq/kg, Th~~mBq/kg, K~0.54~mBq/kg, and Co~0.02~mBq/kg (68\% CL).
Such low intrinsic activities, which are some of the lowest ever reported for
titanium, enable its use for future dark matter and other rare event searches.
Monte Carlo simulations have been performed to assess the expected background
contribution from the LZ cryostat with this radioactivity. In 1,000 days of
WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute
only a mean background of (stat)(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle
Physic
Transformations in network governance: the case of migration intermediaries
types: Article"This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Ethnic and Migration Studies on 3 February 2015 available online: http://wwww.tandfonline.com/10.1080/1369183X.2014.1003803Market liberalisation has fundamentally changed state interventions in the supply of services and supportive infrastructure across a range of public services. While this trend has been relatively well documented, there has been a dearth of research into the changing nature of state interventions in migration and mobility. Indeed the increasing presence of migration intermediaries to service the many and varied needs of migrant workers, particularly skilled migrants, remains significantly under-researched both theoretically and empirically. In providing an analysis of the location, role and changing nature of migration intermediaries, we highlight the implications of commercially-driven governance structures. In particular we suggest that the shift from government to network governance has important implications for skilled migration including: inequities in access to information regarding the process of migration and labour market integration; and, greater dependence on (largely unregulated) private intermediaries. Accordingly, we present empirical examples of migration intermediaries to illustrate their role and the relationship with and implications of their exchange with migrants
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