35 research outputs found
Nuclear and nucleon transitions of the H di-baryon
We consider 3 types of processes pertinent to the phenomenology of an H
di-baryon: conversion of two 's in a doubly-strange hypernucleus to an
H, decay of the H to two baryons, and -- if the H is light enough -- conversion
of two nucleons in a nucleus to an H. We compute the spatial wavefunction
overlap using the Isgur-Karl and Bethe-Goldstone wavefunctions, and treat the
weak interactions phenomenologically. The observation of decays from
doubly-strange hypernuclei puts a constraint on the H wavefunction which is
plausibly satisfied. In this case the H is very long-lived as we calculate. An
absolutely stable H is not excluded at present. SuperK can provide valuable
limits
Quantifying interictal intracranial EEG to predict focal epilepsy
Intracranial EEG (IEEG) is used for 2 main purposes, to determine: (1) if
epileptic networks are amenable to focal treatment and (2) where to intervene.
Currently these questions are answered qualitatively and sometimes differently
across centers. There is a need for objective, standardized methods to guide
surgical decision making and to enable large scale data analysis across centers
and prospective clinical trials.
We analyzed interictal data from 101 patients with drug resistant epilepsy
who underwent presurgical evaluation with IEEG. We chose interictal data
because of its potential to reduce the morbidity and cost associated with ictal
recording. 65 patients had unifocal seizure onset on IEEG, and 36 were
non-focal or multi-focal. We quantified the spatial dispersion of implanted
electrodes and interictal IEEG abnormalities for each patient. We compared
these measures against the 5 Sense Score (5SS), a pre-implant estimate of the
likelihood of focal seizure onset, and assessed their ability to predict the
clinicians choice of therapeutic intervention and the patient outcome.
The spatial dispersion of IEEG electrodes predicted network focality with
precision similar to the 5SS (AUC = 0.67), indicating that electrode placement
accurately reflected pre-implant information. A cross-validated model combining
the 5SS and the spatial dispersion of interictal IEEG abnormalities
significantly improved this prediction (AUC = 0.79; p<0.05). The combined model
predicted ultimate treatment strategy (surgery vs. device) with an AUC of 0.81
and post-surgical outcome at 2 years with an AUC of 0.70. The 5SS, interictal
IEEG, and electrode placement were not correlated and provided complementary
information.
Quantitative, interictal IEEG significantly improved upon pre-implant
estimates of network focality and predicted treatment with precision
approaching that of clinical experts.Comment: 25 pages, 4 Figures, 1 tabl
Closing in on Asymmetric Dark Matter I: Model independent limits for interactions with quarks
It is argued that experimental constraints on theories of asymmetric dark
matter (ADM) almost certainly require that the DM be part of a richer hidden
sector of interacting states of comparable mass or lighter. A general requisite
of models of ADM is that the vast majority of the symmetric component of the DM
number density must be removed in order to explain the observed relationship
via the DM asymmetry. Demanding the efficient
annihilation of the symmetric component leads to a tension with experimental
limits if the annihilation is directly to Standard Model (SM) degrees of
freedom. A comprehensive effective operator analysis of the model independent
constraints on ADM from direct detection experiments and LHC monojet searches
is presented. Notably, the limits obtained essentially exclude models of ADM
with mass 1GeV 100GeV annihilating to SM quarks via
heavy mediator states. This motivates the study of portal interactions between
the dark and SM sectors mediated by light states. Resonances and threshold
effects involving the new light states are shown to be important for
determining the exclusion limits.Comment: 18+6 pages, 18 figures. v2: version accepted for publicatio
Testing the Dark Matter Interpretation of the DAMA/LIBRA Result with Super-Kamiokande
We consider the prospects for testing the dark matter interpretation of the
DAMA/LIBRA signal with the Super-Kamiokande experiment. The DAMA/LIBRA signal
favors dark matter with low mass and high scattering cross section. We show
that these characteristics imply that the scattering cross section that enters
the DAMA/LIBRA event rate determines the annihilation rate probed by
Super-Kamiokande. Current limits from Super-Kamiokande through-going events do
not test the DAMA/LIBRA favored region. We show, however, that upcoming
analyses including fully-contained events with sensitivity to dark matter
masses from 5 to 10 GeV may corroborate the DAMA/LIBRA signal. We conclude by
considering three specific dark matter candidates, neutralinos, WIMPless dark
matter, and mirror dark matter, which illustrate the various model-dependent
assumptions entering our analysis.Comment: 10 pages, 1 figure; v2: projected super-K sensitivity corrected and
strengthened, references added; v3: published versio
Sharing clinical information across care settings: the birth of an integrated assessment system
Background: Population ageing, the emergence of chronic illness, and the shift away from institutional care challenge conventional approaches to assessment systems which traditionally are problem and setting specific
Updated Nucleosynthesis Constraints on Unstable Relic Particles
We revisit the upper limits on the abundance of unstable massive relic
particles provided by the success of Big-Bang Nucleosynthesis calculations. We
use the cosmic microwave background data to constrain the baryon-to-photon
ratio, and incorporate an extensively updated compilation of cross sections
into a new calculation of the network of reactions induced by electromagnetic
showers that create and destroy the light elements deuterium, he3, he4, li6 and
li7. We derive analytic approximations that complement and check the full
numerical calculations. Considerations of the abundances of he4 and li6 exclude
exceptional regions of parameter space that would otherwise have been permitted
by deuterium alone. We illustrate our results by applying them to massive
gravitinos. If they weigh ~100 GeV, their primordial abundance should have been
below about 10^{-13} of the total entropy. This would imply an upper limit on
the reheating temperature of a few times 10^7 GeV, which could be a potential
difficulty for some models of inflation. We discuss possible ways of evading
this problem.Comment: 40 pages LaTeX, 18 eps figure
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely