We study perturbations in the multi-field axion N-flation model, taking account of the full cosine potential. We find significant differences with previous analyses which made a quadratic approximation to the potential. The tensor-to-scalar ratio and the scalar spectral index move to lower values, which nevertheless provide an acceptable fit to observation. Most significantly, we find that the bispectrum non-gaussianity parameter fNL may be large, typically of order 10 for moderate values of the axion decay constant, increasing to of order 100 for decay constants slightly smaller than the Planck scale. Such a non-gaussian fraction is detectable. We argue that this property is generic in multi-field models of hilltop inflation. Previous N-flation studies have assumed that all relevant fields are close to their minima and can be described by quadratic potentials. For axions the full potential is trigonometric and we find the quadratic approximation is unreliable. Even for identical potentials, the condition for stable co-evolution of the fields is violated near the hilltop [5]. Therefore fields in this region evolve on divergent trajectories. Accounting for this divergence by retaining the full potential leads to two very significant changes. The predicted scalar spectral index and tensorto-scalar ratio, r, are reduced. This remains compatible with existing observations but may leave r undetectable. More importantly, f NL is predicted to be large, and very plausibly within the range of future probes.This unexpectedly large non-gaussianity is a genuine multi-field phenomenon. It is a consequence of the diverging trajectories near the hilltop, implied by a negative η-parameter of order unity or larger. In single-field models, potentials of this form lead to a density perturbation with a spectral index, n, in conflict with observation. The assisted inflation mechanism reduces 1 − n to an acceptable value, but leaves f NL dominated by the contribution of the field closest to the peak. THE MODELThe axion N-flation model is based on a set of N f uncoupled fields, labelled φ i , each with a potential [2]where α i = 2πφ i /f i and f i is the i th axion decay constant. In a more general model couplings may exist between the fields, but we will not consider these. The mass of each field in vacuum satisfies m i = 2πΛ 2 i /f i , and the angular field variables α i lie in the range (−π, +π]. Without loss of generality we will set initial conditions with all α i positive. If only a single field is present this model is known as natural inflation [6].Calculation of the observables n, r and f NL makes use of the δN formula [7], which considers how the total number of e-folds of expansion N is modified by field perturbations. We define slow-roll parameters for each field aswhere M P ≡ (8πG) −1/2 is the reduced Planck mass, a prime denotes the derivative of a function with respect to its argument, and no summation over i is implied. The global slow-roll parameter ǫ ≡ −Ḣ/H 2 can be written as a weighted sum ǫ ≃ i (V i /V ) 2 ǫ i , i...
ObjectiveTo investigate the sleep state of mild stroke patients and relationship between sleep disturbance and functional status.MethodsA total of 80 acute stroke patients were enrolled in this study. The criteria for inclusion in the study was as following: 1) first stroke, 2) cognitive function preserved enough to perform the test (Mini Mental State Examination ≥24), 3) good functional levels (Modified Rankin Scale ≤3), 4) upper extremity motor function preserved enough to perform occupational tests (hand strength test, Purdue pegboard test, 9-hole peg test, and Medical Research Council score ≥3), and 5) less than 2 weeks between the stroke and the assessment. Quality of sleep was assessed by using Pittsburg Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), and Stanford Sleepiness Scale (SSS). Activities of daily living was assessed by using the Modified Barthel Index (MBI) and depressed mood was assessed by using the Beck Depression Inventory (BDI). Gross and fine motor function of the upper extremity was assessed by using hand strength test (Jamar dynamometer), Purdue pegboard test, and the 9-hole peg test.ResultsThe results of the occupational assessment were fine in the good sleepers. The PSQI, ESS, and ISI were correlated with some of the assessment tools (BDI, MBI, Purdue pegboard, 9-hole peg, and hand strength).ConclusionIn conclusion, this study emphasizes that sleep disturbance can affect the functional status in mild acute stroke patients. Therefore, clinicians must consider sleep status in stroke patients and need to work to control it.
The no-boundary wave function of quantum gravity usually assigns only very small probability to long periods of inflation. This was a reason to doubt about the no-boundary wave function to explain the observational universe. We study the no-boundary proposal in the context of multi-field inflation to see whether the number of fields changes the situation. For a simple model, we find that indeed the no-boundary wave function can give higher probability for sufficient inflation, but the number of fields involved N f has to be very high, e.g., N f ≃ m −2 . *
ObjectiveTo investigate the effects of trigger point injection with or without ischemic compression in treatment of myofascial trigger points in the upper trapezius muscle.MethodsSixty patients with active myofascial trigger points in upper trapezius muscle were randomly divided into three groups: group 1 (n=20) received only trigger point injections, group 2 (n=20) received trigger point injections with 30 seconds of ischemic compression, and group 3 (n=20) received trigger point injections with 60 seconds of ischemic compression. The visual analogue scale, pressure pain threshold, and range of motion of the neck were assessed before treatment, immediately after treatment, and 1 week after treatment. Korean Neck Disability Indexes were assessed before treatment and 1 week after treatment.ResultsWe found a significant improvement in all assessment parameters (p<0.05) in all groups. But, receiving trigger point injections with ischemic compression group showed significant improvement as compared with the receiving only trigger point injections group. And no significant differences between receiving 30 seconds of ischemic compression group and 60 seconds of ischemic compression group.ConclusionThis study demonstrated the effectiveness of ischemic compression for myofascial trigger point. Trigger point injections combined with ischemic compression shows better effects on treatment of myofascial trigger points in the upper trapezius muscle than the only trigger point injections therapy. But the duration of ischemic compression did not affect treatment of myofascial trigger point.
The histone deacetylases (HDACs), Sirtuin 1 (Sirt1) and Sirt2, play crucial roles in many biological processes, including cell proliferation, differentiation and apoptosis. HDAC inhibitors have been considered as a potential therapeutic approach for various types of cancers. Here, we demonstrated that the Sirt1 and Sirt2 inhibitors EX527 and AGK2 suppressed cell growth and caused G1 phase arrest by inhibiting the expression of Cdk6 and/or Cdk4. An agar colony formation assay revealed that EX527 and AGK2 decreased colony formation in soft agar. Furthermore, EX527 and AGK2 pretreatment inhibited the expression of HSF1 and HSP27 and induced HSF1 ubiquitination. Sirt1 overexpression increased HSF1 expression and/or stabilization and induced cell migration in a scratch assay. Overall, these results indicate that EX527 and AGK2 suppress cell growth and migration by inhibiting HSF1 protein stability.
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