A review of brain circuitries involved in stuttering.

Stuttering has been the subject of much research, nevertheless its etiology remains incompletely understood. This article presents a critical review of the literature on stuttering, with particular reference to the role of the basal ganglia (BG). Neuroimaging and lesion studies of developmental and acquired stuttering, as well as pharmacological and genetic studies are discussed. Evidence of structural and functional changes in the BG in those who stutter indicates that this motor speech disorder is due, at least in part, to abnormal BG cues for the initiation and termination of articulatory movements. Studies discussed provide evidence of a dysfunctional hyperdopaminergic state of the thalamocortical pathways underlying speech motor control in stuttering. Evidence that stuttering can improve, worsen or recur following deep brain stimulation for other indications is presented in order to emphasize the role of BG in stuttering. Further research is needed to fully elucidate the pathophysiology of this speech disorder, which is associated with significant social isolation

Analysis of Natural Gas Diversion from Fertilizer Sector to Power Sector in Pakistan

Pakistan is facing an acute energy crisis. The crisis in natural gas sector is just a symptom of a much larger problem afflicting the country’s energy sector as a whole i.e., the demand for natural gas as well as other forms of energy is fast outstripping supply. Pakistan’s gas supplies can’t support the ever-growing demand as they feed power plants, fertilizer companies, domestic consumers, CNG stations and other industries that rely on this fuel. As the energy crisis has worsened over the past five years, the government has consciously curtailed the supply of natural gas to fertilizer sector diverting it to power generation. The gradual reduction in the supply of gas to the fertilizer sector has been accompanied by an increase in gas prices. These two measures have adversely affected this sector and the current study evaluates the economic effects of this policy shift. With the reduction in supply and increase in the price of gas, domestic production of fertilizers has declined whereas their imports have gone up. The PEST analysis including the economic appraisal of two policy options – whether to supply natural gas for either fertilizer production or power generation - makes it quite clear that the supply of gas to the fertilizer sector has higher economic returns. However this appraisal is limited to a cost-benefit analysis and does not take into account the exogenous factors which may have a stronger impact on gas allocation policy. In the end the paper presents different policy options and concludes with a recommendation to undertake wider reforms in the energy sector aimed at increased production of natural gas, enhanced efficiencies in the transmission system and a rationalised tariff structure. Keywords: Fertilizer sector, Economic analysis, Alternative uses of energy, PEST analysis

Charmonium spectrum in an unquenched quark model

The effects of virtual light quark pairs on the charmonium spectrum are studied. Pair creation is modelled with a ``$^{3}P_{0}$" vertex and intermediate states are summed up to 2S excitations. Quark model parameters are obtained by fitting to 12 well-known charmonium states, allowing for feedback between the decaying particle and the induced mass shifts. Both of these technical steps are new and improve agreement with the experimental spectrum. In general, the masses receive small shifts once model parameters are refit. This is true in almost cases except the $\chi_{cJ}(2P)$ multiplet, which experiences upwards mass shifts of order 150 MeV, has the ordering of the multiplet rearranged, and pushes the erstwhile $c\bar{c}$ ${2}^3P_1$ state well above $D^*\bar{D}$ threshold--observations that clarify the nature of the enigmatic $X(3872)

Two cases of near-complete regression of focal nodular hyperplasia of the liver: Case reports and review of the literature

AbstractWhile regression of focal nodular hyperplasia of the liver is not uncommon, reports of near-complete involution or regression of these lesions are rare. We report two cases of focal nodular hyperplasia that underwent near-complete regression—one in a 27-year-old female that regressed over a period of 4 years, and one in a 46-year-old female that regressed over a 7-year period. Both patients discontinued use of exogenous estrogens between the diagnosis of focal nodular hyperplasia and its subsequent regression. Although contemporary cross-sectional imaging has improved the ability to detect and follow these lesions, few studies examining the natural history of focal nodular hyperplasia have been conducted. We discuss pertinent imaging findings on magnetic resonance imaging and computed tomography, and review the literature on regression of focal nodular hyperplasia and the effects of endogenous hormones and exogenous hormone therapy

Vacuum Polarization and Dynamical Chiral Symmetry Breaking: Phase Diagram of QED with Four-Fermion Contact Interaction

We study chiral symmetry breaking for fundamental charged fermions coupled electromagnetically to photons with the inclusion of four-fermion contact self-interaction term. We employ multiplicatively renormalizable models for the photon dressing function and the electron-photon vertex which minimally ensures mass anomalous dimension = 1. Vacuum polarization screens the interaction strength. Consequently, the pattern of dynamical mass generation for fermions is characterized by a critical number of massless fermion flavors above which chiral symmetry is restored. This effect is in diametrical opposition to the existence of criticality for the minimum interaction strength necessary to break chiral symmetry dynamically. The presence of virtual fermions dictates the nature of phase transition. Miransky scaling laws for the electromagnetic interaction strength and the four-fermion coupling, observed for quenched QED, are replaced by a mean-field power law behavior corresponding to a second order phase transition. These results are derived analytically by employing the bifurcation analysis, and are later confirmed numerically by solving the original non-linearized gap equation. A three dimensional critical surface is drawn to clearly depict the interplay of the relative strengths of interactions and number of flavors to separate the two phases. We also compute the beta-function and observe that it has ultraviolet fixed point. The power law part of the momentum dependence, describing the mass function, reproduces the quenched limit trivially. We also comment on the continuum limit and the triviality of QED.Comment: 9 pages, 10 figure

The Prediction of Tear Strength of plain weave fabric Using Linear Regression Models

The aim of the study is to predict the tear strength of plain weave fabric by knowing the yarn count, yarn tensile strength and the fabric linear density. A total of nine fabric samples (produced of three different yarn counts which were 36.88, 29.50 and 9.83 tex) were produced in deferent densities at weft direction which were 4.33, 7.08 and 8.26 threads per cm, while the density was fixed at the warp direction in 9.84 ends per cm . Tensile strength was tested for these fabrics at warp and weft direction. The results were analyzed and incorporated in the Min-Tab program and the development of regression coefficients and correlation between variables to obtain equations to predict the tear strength at warp and weft direction

Combining Fine- and Coarse-Grained Classifiers for Diabetic Retinopathy Detection

Visual artefacts of early diabetic retinopathy in retinal fundus images are usually small in size, inconspicuous, and scattered all over retina. Detecting diabetic retinopathy requires physicians to look at the whole image and fixate on some specific regions to locate potential biomarkers of the disease. Therefore, getting inspiration from ophthalmologist, we propose to combine coarse-grained classifiers that detect discriminating features from the whole images, with a recent breed of fine-grained classifiers that discover and pay particular attention to pathologically significant regions. To evaluate the performance of this proposed ensemble, we used publicly available EyePACS and Messidor datasets. Extensive experimentation for binary, ternary and quaternary classification shows that this ensemble largely outperforms individual image classifiers as well as most of the published works in most training setups for diabetic retinopathy detection. Furthermore, the performance of fine-grained classifiers is found notably superior than coarse-grained image classifiers encouraging the development of task-oriented fine-grained classifiers modelled after specialist ophthalmologists.Comment: Pages 12, Figures