Generalized uncertainty principle impact onto the black holes information flux and the sparsity of Hawking radiation

We investigate the generalized uncertainty principle (GUP) corrections to the entropy content and the information flux of black holes, as well as the corrections to the sparsity of the Hawking radiation at the late stages of evaporation. We find that due to these quantum gravity motivated corrections, the entropy flow per particle reduces its value on the approach to the Planck scale due to a better accuracy in counting the number of microstates. We also show that the radiation flow is no longer sparse when the mass of a black hole approaches Planck mass which is not the case for non-GUP calculations.Comment: 6 pages, 2 figures, typos corrected, published in Phys. Rev.

Minimal length and the flow of entropy from black holes

The existence of a minimal length, predicted by different theories of quantum gravity, can be phenomenologically described in terms of a generalized uncertainty principle. We consider the impact of this quantum gravity motivated effect onto the information budget of a black hole and the sparsity of Hawking radiation during the black hole evaporation process. We show that the information is not transmitted at the same rate during the final stages of the evaporation and that the Hawking radiation is not sparse anymore when the black hole approaches the Planck mass.Comment: Awarded Honorable Mention in the 2018 Gravity Research Foundation Essay Competitio

Diagnostic Accuracy of Clinical Examination in Cervical Spine Injuries in Awake and Alert Blunt Trauma Patients

Study design: Observational, case series.Purpose: To determine the sensitivity and specificity of clinical judgment as compared to the use of X-ray images in detecting cervical spine injuries in trauma patients presenting in the emergency department of Aga Khan University Hospital, Karachi.Overview of literature: Cross-table cervical spine views are important in patients with signs and symptoms relating to cervical spine, but asymptomatic patients constitute a different subgroup. Accuracy of clinical examination in these patients has not been subjected to scrutiny.Methods: All patients with blunt trauma who presented to the emergency department and underwent cross-table X-rays as part of their trauma workup were included. The X-rays were read by a radiologist not aware of the history of the patients. We recorded demographic data along with mechanism of injury, associated neck signs or symptoms whether present or not, cervical spine range of motion, associated injuries and X-ray findings. The history and examination were carried out by the on-call neurosurgery team member. The sensitivity and specificity along with negative and positive predictive value of the clinical examination were calculated. Data were analyzed using SPSS ver. 16.0.Results: Of 50 patients with positive signs and symptoms, 4 (8%) had positive X-rays while only 1 out of 324 (0.3%) with no associated signs and symptoms had positive X-ray findings.Conclusions: The clinical examination is 80% sensitive and 73.98% specific in detecting true cervical spine injuries as compared to C-spine X-rays in alert and awake patients with blunt trauma

Cosmological Constraints on Entropic Cosmology with Matter Creation

We investigate entropic force cosmological models with the possibility of matter creation and energy exchange between the bulk and the horizon of a homogeneous and an isotropic flat Universe. We consider three different kinds of entropy, Bekenstein's, the non-extensive Tsallis-Cirto's and the quartic entropy, plus some phenomenological functional forms for matter creation rate to model different entropic force models and put the observational constraints on them. We show that while most of them are basically indistinguishable from a standard $\Lambda$CDM scenario, the Bekenstein entropic force model with a matter creation rate proportional to the Hubble parameter is statistically highly favored over $\Lambda$CDM. As a general result, we also find that both the Hawking temperature parameter $\gamma$, which relates the energy exchange between the bulk and the boundary of the Universe, and the matter creation rate $\Gamma(t)$, must be very small in order to reproduce observational data.Comment: 13 pages, 2 tables, 1 figure, discussion updated, new references adde

On the foundations of entropic cosmologies: inconsistencies, possible solutions and dead end signs

In this letter we explore the foundations of entropic cosmology and highlight some important flaws which have emerged and adopted in the recent literature. We argue that, when applying entropy and temperature on the cosmological horizon by assuming the holographic principle for all thermodynamic approaches to cosmology and gravity, one must derive the consistent thermodynamic quantities following Clausius relation. One key assumption which is generally overlooked, is that in this process one must assume a mass-to-horizon relation, which is generally taken as a linear one. We show that, regardless of the type of entropy chosen on the cosmological horizon, when a thermodynamically consistent corresponding temperature is considered, all modified entropic force models are equivalent to and indistinguishable from the original entropic force models based on classical Bekenstein entropy and Hawking temperature. As such, they are also plagued by the same problems and inability to describe in a satisfactory qualitative and quantitative way the cosmological dynamics as it emerges from the probes we have. Moreover, we also show that the standard accepted parameterization for the Hawking temperature is actually not correctly applied, i.e. it is not related to entropy in a thermodynamically consistent way. As such, we show what should be done in order to fix that, and what conceptually could be implied by its correct implementation.Comment: 12 page

Nonextensive Black Hole Entropy and Quantum Gravity Effects at the Last Stages of Evaporation

We analyze the Generalized Uncertainty Principle (GUP) impact onto the nonextensive black hole thermodynamics by using R\'enyi entropy. We show that when introducing GUP effects, both R\'enyi entropy and temperature associated to black holes have finite values at the end of the evaporation process. We also study the sparsity of the radiation, associated with R\'enyi temperature, and compare it with the sparsity of Hawking radiation. Finally, we investigate GUP modifications to the sparsity of the radiation when GUP effects are introduced into R\'enyi temperature.Comment: 9 pages, 5 figures, extended introduction, results and conclusion, added new references, accepted in Phys. Rev.

Information extraction from semi and unstructured data sources: a systematic literature review

Millions of structured, semi structured and unstructured documents have been produced around the globe on a daily basis. Sources of such documents are individuals as well as several research societies like IEEE, Elsevier, Springer and Wiley that we use to publish the scientific documents enormously. These documents are a huge resource of scientific knowledge for research communities and interested users around the world. However, due to their massive volume and varying document formats, search engines are facing problems in indexing such documents, thus making retrieval of information inefficient, tedious and time consuming. Information extraction from such documents is among the hottest areas of research in data/text mining. As the number of such documents is increasing tremendously, more sophisticated information extraction techniques are necessary. This research focuses on reviewing and summarizing existing state-of-theart techniques in information extraction to highlight their limitations. Consequently, the research gap is formulated for the researchers in information extraction domain

Lumbar morphometry: A study of lumbar vertebrae from a Pakistani population using computed tomography scans

Study design: A cross-sectional study.Purpose: To describe the characteristics of lumbar vertebrae of Pakistani patients reporting at a tertiary care hospital and compare with studies from other populations.Overview of literature: Several studies have been conducted to determine morphometry of lumbar vertebrae. Most of the studies involve Caucasian populations, still data on other populations still sparse. This is the first study describing lumbar morphometry of a Pakistani population.Methods: An observational study was conducted based on a review of thin-cut (3 mm) computed topographic images of lumbar vertebrae. Two-hundred and twenty vertebrae from forty-nine patients were studied, and various dimensions were analyzed.Results: Generally, the size of the vertebrae, vertebral canals and recesses were found to be greater in male patients. The difference was statistically significant for transverse and anteroposterior diameters of the vertebral bodies and sagittal diameter of pedicles on the left side (p\u3c0.05). Comparison of populations revealed statistically significant differences in pedicle dimensions between Pakistani population and others.Conclusions: This study provides anatomical knowledge of the lumbar region in a sample population of Pakistan. There were significant differences in various dimensions of lumbar vertebrae between female and male patients. This would prove to be critical for performing a safe operation

Response of Tuberose (Polianthes tuberosa) to Potassium and Planting Depth

A research work was carried to find out the effect of planting depths, potassium levels and their interaction during the year 2012. The corms of tuberose were planted at a depth of 5, 10, and 15 cm and were fertilized with four levels of potassium 0, 50, 100 and 150 Kg of K2O per hectare using K2SO4 as a source of K2O. Result of the study revealed that planting depth of 15 cm significantly increased length of spike (56.9 cm), number of florets spike-1 (54.84), and plant height (103.13) cm. Planting depth of 5cm cause decreased number of days to last floret opening (180.08). Potassium level of 150 kg of K2O ha-1 length of spike (55.24 cm), number of florets spike-1 (49.2) and plant height (100.29 cm). Planting depth of 15 cm and fertilizer application of 150 kg of K2O ha-1proved to be superior regarding length of spike opening (64.4cm), number of florets spike-1 (62.2) and plant height (106.20 cm). Hence planting tuberose at a depth of 15cm and fertilizer application of 150 kg of K2O ha-1 is recommended for commercial cultivation of tuberose. Keywords: Tuberose; Potassium; Planting Depth; Number of Florets Spike-1; Spike Length