2,175 research outputs found
Probing Quantum Geometry at LHC
We present an evidence, that the volumes of compactified spaces as well as
the areas of black hole horizons must be quantized in Planck units. This
quantization has phenomenological consequences, most dramatic being for micro
black holes in the theories with TeV scale gravity that can be produced at LHC.
We predict that black holes come in form of a discrete tower with well defined
spacing. Instead of thermal evaporation, they decay through the sequence of
spontaneous particle emissions, with each transition reducing the horizon area
by strictly integer number of Planck units. Quantization of the horizons can be
a crucial missing link by which the notion of the minimal length in gravity
eliminates physical singularities. In case when the remnants of the black holes
with the minimal possible area and mass of order few TeV are stable, they might
be good candidates for the cold dark matter in the Universe.Comment: 14 pages, Late
Axion Protection from Flavor
The QCD axion fails to solve the strong CP problem unless all explicit PQ
violating, Planck-suppressed, dimension n<10 operators are forbidden or have
exponentially small coefficients. We show that all theories with a QCD axion
contain an irreducible source of explicit PQ violation which is proportional to
the determinant of the Yukawa interaction matrix of colored fermions.
Generically, this contribution is of low operator dimension and will
drastically destabilize the axion potential, so its suppression is a necessary
condition for solving the strong CP problem. We propose a mechanism whereby the
PQ symmetry is kept exact up to n=12 with the help of the very same flavor
symmetries which generate the hierarchical quark masses and mixings of the SM.
This "axion flavor protection" is straightforwardly realized in theories which
employ radiative fermion mass generation and grand unification. A universal
feature of this construction is that the heavy quark Yukawa couplings are
generated at the PQ breaking scale.Comment: 16 pages, 2 figure
Environmental predictability drives adaptive within- and transgenerational plasticity of heat tolerance across life stages and climatic regions
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordData availability statement: Data generated in the current study were deposited in Appendix S3
of Supporting InformationAlthough environmental variability and predictability have been proposed as the underlying ecological context in which transgenerational plasticity (TGP) arises, the adaptive significance and interaction with withinâgeneration plasticity (WGP) in such scenarios is still poorly understood. To investigate these questions, we considered the tolerance to upper thermal limits of larvae and adults of the desert endemic Drosophila mojavensis adapted to different climatic regions (Desert vs. Mediterranean climate).
Thermal plasticity was investigated by acclimating parents and offspring at 36°C (vs. at 25°C). We then used historical temperature variation data from both regions to perform individualâbased simulations by modelling expected components of adaptive plasticity in multiple life stages.
Our results indicated that thermal response to ramping heat shocks was more pronounced in larvae, where acclimation treatments in parents and offspring increased their heatâshock performance, while heat knockdown in adults was only increased by offspring acclimation of adults. The relative contribution of WGP and TGP was greater for the population from the more thermally variable Sonoran Desert.
Similarly, individualâbased simulations of evolving maternal effects indicated that variation in tolerance to upper thermal limits across life stages and climates is expected from its adaptive significance in response to environmental predictability.
Our approach offers a new perspective and interpretation of adaptive plasticity, demonstrating that environmental predictability can drive thermal responses across generations and life stages in a scenario with regional climate variability.University of ArizonaNational Science Foundation (NSF)Leverhulme Trus
Socioeconomic inequalities in cancer survival in Scotland 1986â2000
We analysed trends in 5-year survival of the 18 commonest cancers in Scotland diagnosed between 1986 and 2000 and followed up to 2004 in each of five deprivation groups based on patients postcode of residence at diagnosis. We estimated relative survival up to 5 years after diagnosis, adjusting for the different background mortality in each deprivation group by age, sex and calendar period. We estimated trends in overall survival and in the deprivation gap in survival up to 2004. Five-year survival improved for all malignancies except bladder cancer and was associated with a widening in the deprivation gap in survival. For 25 of 30 cancerâsex combinations examined, 5-year survival was lower among more deprived patients diagnosed during 1996â2000, and the deprivation gap in survival had widened since 1986â1990 for 15 of these 25 cancers, similar to the trends seen in England and Wales
Young women's use of a microbicide surrogate: The complex influence of relationship characteristics and perceived male partners' evaluations
This is the post-print version of the article. The official published version can be found at the link below.Currently in clinical trials, vaginal microbicides are proposed as a female-initiated method of sexually transmitted infection prevention. Much of microbicide acceptability research has been conducted outside of the United States and frequently without consideration of the social interaction between sex partners, ignoring the complex gender and power structures often inherent in young womenâs (heterosexual) relationships. Accordingly, the purpose of this study was to build on existing microbicide research by exploring the role of male partners and relationship characteristics on young womenâs use of a microbicide surrogate, an inert vaginal moisturizer (VM), in a large city in the United States. Individual semi-structured interviews were conducted with 40 young women (18â23 years old; 85% African American; 47.5% mothers) following use of the VM during coital events for a 4 week period. Overall, the results indicated that relationship dynamics and perceptions of male partners influenced VM evaluation. These two factors suggest that relationship context will need to be considered in the promotion of vaginal microbicides. The findings offer insights into how future acceptability and use of microbicides will be influenced by gendered power dynamics. The results also underscore the importance of incorporating men into microbicide promotion efforts while encouraging a dialogue that focuses attention on power inequities that can exist in heterosexual relationships. Detailed understanding of these issues is essential for successful microbicide acceptability, social marketing, education, and use.This study was funded by a grant from National Institutes of Health (NIHU19AI 31494) as well as research awards to the first author: Friends of the Kinsey Institute Research Grant Award, Indiana Universityâs School of HPER Graduate Student Grant-in-Aid of Research Award, William L. Yarber Sexual Health Fellowship, and the Indiana University Graduate and Professional Student Organization Research Grant
Fracture-fill calcite as a record of microbial methanogenesis and fluid migration: a case study from the Devonian Antrim Shale, Michigan Basin
The Devonian Antrim Shale is an organic-rich, naturally fractured black shale in the Michigan Basin that serves as both a source and reservoir for natural gas. A well-developed network of major, through-going vertical fractures controls reservoir-scale permeability in the Antrim Shale. Many fractures are open, but some are partially sealed by calcite cements that retain isotopic evidence of widespread microbial methanogenesis. Fracture filling calcite displays an unusually broad spectrum of δ 13 C values (+34 to â41â° PDB), suggesting that both aerobic and anaerobic bacterial processes were active in the reservoir. Calcites with high δ 13 C values (>+15â°) record cementation of fractures from dissolved inorganic carbon (DIC) generated during bacterial methanogenesis. Calcites with low δ 13 C values (<â32â°) are solely associated with outcrop samples and record methane oxidation during cement precipitation. Fracture-fill calcite with δ 13 C values between â10 and â30â° can be attributed to variable organic matter oxidation pathways, methane oxidation, and carbonate rock buffering. Identification of 13 C-rich calcite provides unambiguous evidence of biogenic methane generation and may be used to identify gas deposits in other sedimentary basins. It is likely that repeated glacial advances and retreats exposed the Antrim Shale at the basin margin, enhanced meteoric recharge into the shallow part of the fractured reservoir, and initiated multiple episodes of bacterial methanogenesis and methanotrophic activity that were recorded in fracture-fill cements. The δ 18 O values in both formation waters and calcite cements increase with depth in the basin (â12 to â4â° SMOW, and +21 to +27â° PDB, respectively). Most fracture-fill cements from outcrop samples have δ 13 C values between â41 and â15â° PDB. In contrast, most cement in cores have δ 13 C values between +15 and +34â° PDB. Radiocarbon and 230 Th dating of fracture-fill calcite indicates that the calcite formed between 33 and 390âka, well within the Pleistocene Epoch.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75720/1/j.1468-8123.2002.00036.x.pd
- âŚ