Generation and Life Cycle of Solar Spicules

Physical mechanism for the creation of solar spicules with three stages of their life cycle is investigated. It is assumed that at stage-I, the density hump is formed locally in the chromosphere in the presence of temperature gradients of electrons and ions along the z-axis. The density structure is accelerated in the vertical direction due to the thermal force ${\bf F}_{th} \propto \nabla n(x,y,t) \times (\nabla T_e + \nabla T_i)$. The magnitude of the upward acceleration depends on the steepness of the temperature gradients $\nabla T_j$ where $j=(e,i)$. The exact time-dependent 2D analytical solution of two fluid plasma equations is presented assuming that the exponentially decaying density structure is created in the xy plane and evolves in time as a step function $H(t)$ . The upward acceleration $a$ produced in this density structure is greater than the downward solar acceleration $g_\odot$. The vertical plasma velocity turns out to be the ramp function of time $R(t)$ whereas the source term for the density follows the delta function $\delta(t)$. In the transition region (TR), the temperature gradients are steeper and itupward acceleration increases in magnitude $g_\odot << a$ and density hump spends lesser time here. This is stage-II of its life cycle. In stage-III, the density structure enters the corona where the gradients of temperatures vanish and structure moves upward with almost constant speed which is slowly reduced to zero due to negative solar gravitational force because ${\bf a} \simeq - {\bf g}_\odot$. The estimates of height $H$ and life time $\tau_l$ of the spicule are in agreement with the observed values.Comment: 22 pages, 3 fig

Subtracted Geometry

In this thesis we study a special class of black hole geometries called subtracted geometries. Subtracted geometry black holes are obtained when one omits certain terms from the warp factor of the metric of general charged rotating black holes. The omission of these terms allows one to write the wave equation of the black hole in a completely separable way and one can explicitly see that the wave equation of a massless scalar field in this slightly altered background of a general multi-charged rotating black hole acquires an $SL(2,\mathbb{R}) \times \times SL(2,\mathbb{R}) \times SO(3)$ symmetry. The ”subtracted limit” is considered an appropriate limit for studying the internal structure of the non-subtracted black holes because new \u27subtracted\u27 black holes have the same horizon area and periodicity of the angular and time coordinates in the near horizon regions as the original black hole geometry it was constructed from. The new geometry is asymptotically conical and is physically similar to that of a black hole in an asymptotically confining box. We use the different nice properties of these geometries to understand various classically and quantum mechanically important features of general charged rotating black holes

Dispersion Properties of Co-Existing Low Frequency Modes in Quantum Plasmas

Non

HRCT Spectrum in Initially COVID-19 RT-PCR Negative Patients

Objective: To analyze radiological spectrum of HRCT in COVID-19 patients, clinically symptomatic but initially having negative RT-PCR. Study Design: Prospective cross sectional descriptive study. Place and Duration of Study: Radiology and Medicine Department, DHQ Hospital Rawalpindi, from June to November 2020 Methodology: The study included 90 patients presenting with clinical symptoms of COVID-19 but with negative RT-PCR. All patients underwent chest computed tomography (CT). Patients with positive COVID-19 RT-PCR test or serology on subsequent repeat test were included in the study. Patients having non COVID-19 HRCT features with negative RT-PCR were excluded from the study. Results: Out of 90 symptomatic, RT-PCR negative patients, 7 had normal chest CT. According to BSTI classification, 50 patients showed classic, 11 had probable and 22 had indeterminate features. Despite supportive clinical and CT features, 17 (18.89%) patients had negative RT-PCR tests on subsequent testing. Unilateral changes were in 8 (8.9%) and bilateral in 75 (83.3%). Most common finding was mixed pattern of peripherally distributed GGN and bronchocentric nodules in 37 (41.1%) patients. Consolidations were in 19 (21.1%), pure ground glass haze in 13 (14.4%), crazy paving in 4 (4.4%), fuzzy bands and arcades in 7 (7.8%), and subtle gravitational GGH in 3 (3.3%) patients. CT-SS classified 69 (76.7%) patients as mild, 10 (11.1%) as moderate and 4 (4.4%) as severe disease. Conclusions: HRCT with CTSS is an important tool for diagnosing and prognosticating COVID-19 infection despite negative RT-PCR, timely identifying and isolating COVID-19 cohorts preventing cross infection and also aiding in prompt symptomatic management

Death Penalty Suspension Approach in Pakistan with Chinese Characteristics

Since the death penalty abolition campaign started, Pakistan is lagging behind to do any substantive reforms in the penal system. The reason for retention of death penalty is rooted in the Islamic injunctions which Pakistan being Islamic Republic cannot ignore. Any contradictory provision will be declared null and void and unconstitutional as the preamble of Constitution of Pakistan 1973 expressly mention it. Keeping in mind the case of Pakistan where complete abolition seems difficult but is willing to reduce it to maximum extent. The article doing a comparative analysis of penal system of Pakistan and China, bring a suitable model that can help reduce the death penalty. Pertaining to the situation of China which is also ambitious to reduce the execution but not convinced yet to complete abolition, the Chinese model of “suspended death penalty” which is well recognized and practical to reduce the executions can serve as a good model for Pakistan to follow. The article will provide the analysis of situation of Pakistan penal system and the compatibility of Chinese model as a perfect extension for reducing the number of executions though not complete abolition. It also narrates the working mechanism of suspended death penalty of China and its effectivity regarding civilizing death penalty regime. Keywords: Death penalty, suspended death penalty, abolition, China, Pakistan penal code