4,777 research outputs found
LEP and radiative electroweak breaking close the light gluino window
We show that the LEP lower bound on the chargino mass, in conjunction with
the well motivated theoretical requirement of radiative electroweak symmetry
breaking, imply an upper bound on the lightest Higgs boson mass
(m_h\lsim62\GeV) in a supersymmetry breaking scenario where the gluino mass
is a few GeV. Moreover, Higgs searches at LEP in the context of this model
require m_h\gsim61\GeV. The remaining experimentally allowed region in the
five-dimensional parameter space of this light gluino model is severely
fine-tuned (with and m_t=114.0-114.3\GeV) and
cosmologically troublesome (with a neutralino relic abundance over {\it
five-hundred times larger than allowed}). Modest improvements in sensitivity in
LEP Higgs searches and Tevatron top-quark searches should soon exclude this
theoretically disfavored model completely.Comment: 6 pages, no figures, tex (harvmac), CERN-TH.6890, CTP-TAMU-25/9
Supersymmetric photonic signals at LEP
We explore and contrast the single-photon and diphoton signals expected at
LEP 2, that arise from neutralino-gravitino (e^+ e^- -> chi + gravitino ->
gamma + E_miss) and neutralino-neutralino (e^+ e^- -> chi + chi -> gamma +
gamma + E_miss) production in supersymmetric models with a light gravitino. LEP
1 limits imply that one may observe either one, but not both, of these signals
at LEP 2, depending on the values of the neutralino and gravitino masses:
single-photons for m_chi > Mz and m_gravitino < 3 x 10^-5 eV; diphotons for
m_chi < Mz and all allowed values of m_gravitino.Comment: 11 pages, LaTeX, 4 figures (included). Shortened version to appear in
Physical Review Letter
The top-quark mass in SU(5)xU(1) supergravity
We show that the currently experimentally preferred values of the top-quark
mass (\ie, 130\lsim m_t\lsim180\GeV) are naturally understood in the context
of string models, where the top-quark Yukawa coupling at the string scale is
generically given by , with the unified gauge
coupling. A detailed study of the Yukawa sector of
supergravity shows that the ratio of the bottom-quark to tau-lepton Yukawa
couplings at the string scale is required to be in the range
0.7\lsim\lambda_b/\lambda_\tau\lsim1, depending on the values of and
. This result is consistent with symmetry, which does
{\em not} require the equality of these Yukawa couplings in the unbroken
symmetry phase of the theory. As a means of possibly predicting the value of
, we propose a procedure whereby the size of the allowed parameter space
is determined as a function of , since all sparticle and Higgs-boson
masses and couplings depend non-trivially on . At present, no significant
preference for particular values of in supergravity is
observed, except that high-precision LEP data requires m_t\lsim180\GeV.Comment: latex, 10 pages, 4 figures (included), CERN-TH.7138/94,
CTP-TAMU-05/9
Gauge and Matter Condensates in Realistic String Models
We examine the inter-relationship of the superpotential containing hidden and
observable matter fields and the ensuing condensates in free fermionic string
models. These gauge and matter condensates of the strongly interacting hidden
gauge groups play a crucial role in the determination of the physical
parameters of the observable sector. Supplementing the above information with
the requirement of modular invariance, we find that a generic model with only
trilinear superpotential allows for a degenerate (and sometimes pathological)
set of vacua. This degeneracy may be lifted by higher order terms in the
superpotential. We also point out some other subtle points that may arise in
calculations of this nature. We exemplify our observations by computing
explicitly the modular invariant gaugino and matter condensates in the flipped
SU(5) string model with hidden gauge group .Comment: 11 pages (7 if reduced
Status of the superworld: from theory to experiment
Review to appear in Progress in Particle and Nuclear Physics. Contents:
{1}Introduction}{1} {2}High precision LEP data and convergence of couplings:
physics is not Euclidean geometry}{2} {3}Interconnections between the measured
quantities due to Unification}{7} {4}The origin of and why it should
be abandoned: masses and spectra are needed}{13} {5}The new step forward:
Supergravity}{21} {6}The SU(5) Supergravity Model}{22} {7}SU(5)xU(1)
Supergravity}{32} {8}Detailed calculations for the Tevatron}{47} {9}Detailed
calculations for LEP}{48} {10}Detailed calculations for HERA}{53} {11}Detailed
calculations for Underground Labs and Underwater facilities}{55} {12}Detailed
calculations for indirect experimental detection}{65} {13}The problem of mass
and }{73} {14}Conclusions}{77}Comment: 90 pages, 41 figures (not included), latex. Send requests for hard
copies to "[email protected]". CERN-TH.7136/94, CTP-TAMU-80/9
Habitat disturbance and the organization of bacterial communities in Neotropical hematophagous arthropods
The microbiome plays a key role in the biology, ecology and evolution of arthropod vectors of human pathogens. Vector-bacterial interactions could alter disease transmission dynamics through modulating pathogen replication and/or vector fitness. Nonetheless, our understanding of the factors shaping the bacterial community in arthropod vectors is incomplete. Using large-scale 16S amplicon sequencing, we examine how habitat disturbance structures the bacterial assemblages of field-collected whole-body hematophagous arthropods that vector human pathogens including mosquitoes (Culicidae), sand flies (Psychodidae), biting midges (Ceratopogonidae) and hard ticks (Ixodidae). We found that all comparisons of the bacterial community among species yielded statistically significant differences, but a difference was not observed between adults and nymphs of the hard tick, Haemaphysalis juxtakochi. While Culicoides species had the most distinct bacterial community among dipterans, tick species were composed of entirely different bacterial OTU’s. We observed differences in the proportions of some bacterial types between pristine and disturbed habitats for Coquillettidia mosquitoes, Culex mosquitoes, and Lutzomyia sand flies, but their associations differed within and among arthropod assemblages. In contrast, habitat quality was a poor predictor of differences in bacterial classes for Culicoides biting midges and hard tick species. In general, similarities in the bacterial communities among hematophagous arthropods could be explained by their phylogenetic relatedness, although intraspecific variation seems influenced by habitat disturbance.The microbiome plays a key role in the biology, ecology and evolution of arthropod vectors of human pathogens. Vector-bacterial interactions could alter disease transmission dynamics through modulating pathogen replication and/or vector fitness. Nonetheless, our understanding of the factors shaping the bacterial community in arthropod vectors is incomplete. Using large-scale 16S amplicon sequencing, we examine how habitat disturbance structures the bacterial assemblages of field-collected whole-body hematophagous arthropods that vector human pathogens including mosquitoes (Culicidae), sand flies (Psychodidae), biting midges (Ceratopogonidae) and hard ticks (Ixodidae). We found that all comparisons of the bacterial community among species yielded statistically significant differences, but a difference was not observed between adults and nymphs of the hard tick, Haemaphysalis juxtakochi. While Culicoides species had the most distinct bacterial community among dipterans, tick species were composed of entirely different bacterial OTU’s. We observed differences in the proportions of some bacterial types between pristine and disturbed habitats for Coquillettidia mosquitoes, Culex mosquitoes, and Lutzomyia sand flies, but their associations differed within and among arthropod assemblages. In contrast, habitat quality was a poor predictor of differences in bacterial classes for Culicoides biting midges and hard tick species. In general, similarities in the bacterial communities among hematophagous arthropods could be explained by their phylogenetic relatedness, although intraspecific variation seems influenced by habitat disturbance
Restrictive ID policies: implications for health equity
We wish to thank Synod Community Services for their critical work to develop, support, and implement a local government-issued ID in Washtenaw County, MI. We also thank Yousef Rabhi of the Michigan House of Representatives and Janelle Fa'aola of the Washtenaw ID Task Force, Lawrence Kestenbaum of the Washtenaw County Clerk's Office, Sherriff Jerry Clayton of the Washtenaw County Sherriff's Office, and the Washtenaw ID Task Force for their tireless commitment to developing and supporting the successful implementation of the Washtenaw ID. Additionally, we thank Vicenta Vargas and Skye Hillier for their contributions to the Washtenaw ID evaluation. We thank the Curtis Center for Research and Evaluation at the University of Michigan School of Social Work, the National Center for Institutional Diversity at the University of Michigan, and the University of California-Irvine Department of Chicano/Latino Studies and Program in Public Health for their support of the Washtenaw ID community-academic research partnership. Finally, we thank the reviewers for their helpful comments on earlier drafts of this manuscript. (Curtis Center for Research and Evaluation at the University of Michigan School of Social Work; National Center for Institutional Diversity at the University of Michigan; University of California-Irvine Department of Chicano/Latino Studies; Program in Public Health)https://link.springer.com/content/pdf/10.1007/s10903-017-0579-3.pdfPublished versio
Evaluation of bone turnover markers and serum minerals variations for predicting fracture healing versus non-union processes in adult sheep as a model for orthopedic research
Bone turnover markers (BTMs) have been considered as an auxiliary method of following the fracture healing process and for early prediction of impaired bone healing. A better understanding of the potential of BTMs in this application could allow for earlier interventions and improved patient care. The aim of this study with a large animal experimental model was to assess the variation of bone formation markers SOH namely the total alkaline phosphatase (ALP) and its bone-specific isoform (BALP), serum concentration of intact osteocalcin (OC), N-terminal propeptide type III procollagen (PIIINP) and of bone resorption markers â  namely tartrate resistant acid phosphatase (TRAP) and deoxypyridinoline crosslink (DPD) during the first stages of a normal fracture healing process and of a segmental critical size defect (CSD), which progresses to a non-union process. Thirty healthy female sheep (Portuguese Churra-da-Terra- Quente breed), approximately 4-years-old, were enrolled in this study. Jugular venous blood samples were collected pre-operatively and at 1, 2, 3, 4, 6, 8, 10 and 12 post-operative weeks. The animals of the CSD group showed significant lower serum levels of BALP, OC and significant higher serum PIIINP levels at early stages of the fracture healing process, compared with animals that progressed in a normal fracture healing process. Serum BALP, OC and PIIINP levels could be useful as non-invasive auxiliary tools with other complementary methods for predicting the outcome of traumatic bone fractures.Cristina P. Sousa acknowledges the Portuguese Foundation for Science and Technology (FCT) for her PhD scholarship (Grant No SFRH/BD/45018/2008).info:eu-repo/semantics/publishedVersio
Supersymmetry, Supergravity and R_b revisited in the light of LEP 2
A previous study of supersymmetric models has indicated that they are
unlikely to make a large contribution to R_b. We revisit this analysis, taking
into account the improved lower limits on sparticle masses provided recently by
LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot
contribute more than about one-and-a-half current experimental standard
deviations to R_b. We then specialize this analysis to minimal supergravity
models with universal high-energy boundary conditions, and find a much more
stringent upper bound R^{susy}_b < 0.0003. We discuss in detail why such models
can only attain values of R^{susy}_b that are considerably smaller even than
those obtainable in more general supersymmetric models.Comment: 11 pages, LaTeX, 4 figures (included
Galectin-1 prevents pathological vascular remodeling in atherosclerosis and abdominal aortic aneurysm
Pathological vascular remodeling is the underlying cause of atherosclerosis and abdominal aortic aneurysm (AAA). Here, we analyzed the role of galectin-1 (Gal-1), a β-galactoside-binding protein, as a therapeutic target for atherosclerosis and AAA. Mice lacking Gal-1 (Lgals1 −/− ) developed severe atherosclerosis induced by pAAV/D377Y-mPCSK9 adenovirus and displayed higher lipid levels and lower expression of contractile markers of vascular smooth muscle cells (VSMCs) in plaques than wild-type mice. Proteomic analysis of Lgals1 −/− aortas showed changes in markers of VSMC phenotypic switch and altered composition of mitochondrial proteins. Mechanistically, Gal-1 silencing resulted in increased foam cell formation and mitochondrial dysfunction in VSMCs, while treatment with recombinant Gal-1 (rGal-1) prevented these effects. Furthermore, rGal-1 treatment attenuated atherosclerosis and elastase-induced AAA, leading to higher contractile VSMCs in aortic tissues. Gal-1 expression decreased in human atheroma and AAA compared to control tissue. Thus, Gal-1-driven circuits emerge as potential therapeutic strategies in atherosclerosis and AAA. Galectin-1 plays an essential role in prevention of atherosclerosis and abdominal aortic aneurysm
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