589 research outputs found
Planck Scale Boundary Conditions and the Higgs Mass
If the LHC does only find a Higgs boson in the low mass region and no other
new physics, then one should reconsider scenarios where the Standard Model with
three right-handed neutrinos is valid up to Planck scale. We assume in this
spirit that the Standard Model couplings are remnants of quantum gravity which
implies certain generic boundary conditions for the Higgs quartic coupling at
Planck scale. This leads to Higgs mass predictions at the electroweak scale via
renormalization group equations. We find that several physically well motivated
conditions yield a range of Higgs masses from 127-142 GeV. We also argue that a
random quartic Higgs coupling at the Planck scale favors M_H > 150 GeV, which
is clearly excluded. We discuss also the prospects for differentiating
different boundary conditions imposed for \lambda(M_{pl}) at the LHC. A
striking example is M_H = 127\pm 5 GeV corresponding to \lambda(M_{pl})=0,
which would imply that the quartic Higgs coupling at the electroweak scale is
entirely radiatively generated.Comment: 12 pages, 5 figures; references added and other minor improvements,
matches version published in JHE
Neural Representations of Personally Familiar and Unfamiliar Faces in the Anterior Inferior Temporal Cortex of Monkeys
To investigate the neural representations of faces in primates, particularly in
relation to their personal familiarity or unfamiliarity, neuronal activities
were chronically recorded from the ventral portion of the anterior inferior
temporal cortex (AITv) of macaque monkeys during the performance of a facial
identification task using either personally familiar or unfamiliar faces as
stimuli. By calculating the correlation coefficients between neuronal responses
to the faces for all possible pairs of faces given in the task and then using
the coefficients as neuronal population-based similarity measures between the
faces in pairs, we analyzed the similarity/dissimilarity relationship between
the faces, which were potentially represented by the activities of a population
of the face-responsive neurons recorded in the area AITv. The results showed
that, for personally familiar faces, different identities were represented by
different patterns of activities of the population of AITv neurons irrespective
of the view (e.g., front, 90° left, etc.), while different views were not
represented independently of their facial identities, which was consistent with
our previous report. In the case of personally unfamiliar faces, the faces
possessing different identities but presented in the same frontal view were
represented as similar, which contrasts with the results for personally familiar
faces. These results, taken together, outline the neuronal representations of
personally familiar and unfamiliar faces in the AITv neuronal population
Phenomenology of Light Sneutrino Dark Matter in cMSSM/mSUGRA with Inverse Seesaw
We study the possibility of a light Dark Matter (DM) within a constrained
Minimal Supersymmetric Standard Model (cMSSM) framework augmented by a SM
singlet-pair sector to account for the non-zero neutrino masses by inverse
seesaw mechanism. Working within a 'hybrid' scenario with the MSSM sector fixed
at high scale and the singlet neutrino sector at low scale, we find that,
contrary to the case of the usual cMSSM where the neutralino DM cannot be very
light, we can have a light sneutrino DM with mass below 100 GeV satisfying all
the current experimental constraints from cosmology, collider as well as
low-energy experiments. We also note that the supersymmetric inverse seesaw
mechanism with sneutrino as the lightest supersymmetric partner can have
enhanced same-sign dilepton final states with large missing transverse energy
(mET) coming from the gluino- and squark-pair as well as the squark-gluino
associated productions and their cascade decay through charginos. We present a
collider study for the same-sign dilepton+jets+mET signal in this scenario and
propose some distinctions with the usual cMSSM. We also comment on the
implications of such a light DM scenario on the invisible decay width of an 125
GeV Higgs boson.Comment: 24 pages, 4 figures, 7 tables; matches published versio
Use of surface plasmon resonance for the measurement of low affinity binding interactions between HSP72 and measles virus nucleocapsid protein
The 72 kDa heat shock protein (HSP72) is a molecular chaperone that binds native protein with low affinity. These interactions can alter function of the substrate, a property known as HSP-mediated activity control. In the present work, BIAcore instrumentation was used to monitor binding reactions between HSP72 and naturally occurring sequence variants of the measles virus (MV) nucleocapsid protein (N), a structural protein regulating transcription/replication of the viral genome. Binding reactions employed synthetic peptides mimicking a putative HSP72 binding motif of N. Sequences were identified that bound HSP72 with affinities comparable to well-characterized activity control reactions. These sequences, but not those binding with lesser affinity, supported HSP72 activity control of MV transcription/replication. BIAcore instrumentation thus provides an effective way to measure biologically relevant low affinity interactions with structural variants of viral proteins
How Human Brucellosis Incidence in Urban Kampala Can Be Reduced Most Efficiently? A Stochastic Risk Assessment of Informally-Marketed Milk
In Kampala, Uganda, studies have shown a significant incidence of human brucellosis. A stochastic risk assessment involving two field surveys (cattle farms and milk shops) and a medical record survey was conducted to assess the risk of human brucellosis infection through consumption of informally marketed raw milk potentially infected with Brucella abortus in Kampala and to identify the best control options.In the cattle farm survey, sera of 425 cows in 177 herds in the Kampala economic zone were sampled and tested for brucellosis using a competitive enzyme-linked immunosorbent assay (CELISA). Farmers were interviewed for dairy information. In the milk shop surveys, 135 milk sellers in the urban areas were interviewed and 117 milk samples were collected and tested using an indirect enzyme-linked immunosorbent assay (IELISA). A medical record survey was conducted in Mulago National Referral Hospital for serological test results. A risk model was developed synthesizing data from these three surveys. Possible control options were prepared based on the model and the reduction of risk was simulated for each scenario. Overall, 12.6% (6.8-18.9: 90%CI) of informally marketed milk in urban Kampala was contaminated with B.abortus at purchase and the annual incidence rate was estimated to be 5.8 (90% CI: 5.3-6.2) per 10,000 people. The best control option would be the construction of a milk boiling centre either in Mbarara, the largest source of milk, or in peri-urban Kampala and to ensure that milk traders always sell milk to the boiling centre; 90% success in enforcing these two options would reduce risk by 47.4% (21.6-70.1: 90%CI) and 82.0% (71.0-89.0: 90%CI), respectively.This study quantifies the risk of human brucellosis infection through informally marketed milk and estimates the incidence rate in Kampala for the first time; risk-based mitigation strategies are outlined to assist in developing policy
Are movement disorders and sensorimotor injuries pathologic synergies? When normal multi-joint movement synergies become pathologic
The intact nervous system has an exquisite ability to modulate the activity of multiple muscles acting at one or more joints to produce an enormous range of actions. Seemingly simple tasks, such as reaching for an object or walking, in fact rely on very complex spatial and temporal patterns of muscle activations. Neurological disorders such as stroke and focal dystonia affect the ability to coordinate multi-joint movements. This article reviews the state of the art of research of muscle synergies in the intact and damaged nervous system, their implications for recovery and rehabilitation, and proposes avenues for research aimed at restoring the nervous system’s ability to control movement
The effective Standard Model after LHC Run I
We treat the Standard Model as the low-energy limit of an effective field theory that incorporates higher-dimensional operators to capture the effects of decoupled new physics. We consider the constraints imposed on the coefficients of dimension-6 operators by electroweak precision tests (EWPTs), applying a framework for the effects of dimension- 6 operators on electroweak precision tests that is more general than the standard S, T formalism, and use measurements of Higgs couplings and the kinematics of associated Higgs production at the Tevatron and LHC, as well as triple-gauge couplings at the LHC. We highlight the complementarity between EWPTs, Tevatron and LHC measurements in obtaining model-independent limits on the effective Standard Model after LHC Run 1. We illustrate the combined constraints with the example of the two-Higgs doublet model
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