383 research outputs found
Constraining Bosonic Supersymmetry from Higgs results and 8 TeV ATLAS multi-jets plus missing energy data
The collider phenomenology of models with Universal Extra Dimensions (UED) is
surprisingly similar to that of supersymmetric (SUSY) scenarios. For each
level-1 bosonic (fermionic) Kaluza-Klein (KK) state, there is a fermionic
(bosonic) analog in SUSY and thus UED scenarios are often known as bosonic
supersymmetry. The minimal version of UED (mUED) gives rise to a
quasi-degenerate particle spectrum at each KK-level and thus, can not explain
the enhanced Higgs to diphoton decay rate hinted by the ATLAS collaboration of
the Large Hadron Collider (LHC) experiment. However, in the non-minimal version
of the UED (nmUED) model, the enhanced Higgs to diphoton decay rate can be
easily explained via the suitable choice of boundary localized kinetic (BLK)
terms for higher dimensional fermions and gauge bosons. BLK terms remove the
degeneracy in the KK mass spectrum and thus, pair production of level-1 quarks
and gluons at the LHC gives rise to hard jets, leptons and large missing energy
in the final state. These final states are studied in details by the ATLAS and
CMS collaborations in the context of SUSY scenarios. We find that the absence
of any significant deviation of the data from the Standard Model (SM)
prediction puts a lower bound of about 2.1 TeV on equal mass excited quarks and
gluons.Comment: 19 page
Tea drinking and cognitive function in oldest-old Chinese
10.1007/s12603-012-0077-1The Journal of Nutrition, Health & Aging169754-75
Acetate Kinase Isozymes Confer Robustness in Acetate Metabolism
Acetate kinase (ACK) (EC no: 2.7.2.1) interconverts acetyl-phosphate and acetate to either catabolize or synthesize acetyl-CoA dependent on the metabolic requirement. Among all ACK entries available in UniProt, we found that around 45% are multiple ACKs in some organisms including more than 300 species but surprisingly, little work has been done to clarify whether this has any significance. In an attempt to gain further insight we have studied the two ACKs (AckA1, AckA2) encoded by two neighboring genes conserved in Lactococcus lactis (L. lactis) by analyzing protein sequences, characterizing transcription structure, determining enzyme characteristics and effect on growth physiology. The results show that the two ACKs are most likely individually transcribed. AckA1 has a much higher turnover number and AckA2 has a much higher affinity for acetate in vitro. Consistently, growth experiments of mutant strains reveal that AckA1 has a higher capacity for acetate production which allows faster growth in an environment with high acetate concentration. Meanwhile, AckA2 is important for fast acetate-dependent growth at low concentration of acetate. The results demonstrate that the two ACKs have complementary physiological roles in L. lactis to maintain a robust acetate metabolism for fast growth at different extracellular acetate concentrations. The existence of ACK isozymes may reflect a common evolutionary strategy in bacteria in an environment with varying concentrations of acetate
- …