Galileon gravity and its relevance to late time cosmic acceleration

We consider the covariant galileon gravity taking into account the third order and fourth order scalar field Lagrangians L_3(\pi) and L_4(\pi) consisting of three and four $\pi$'s with four and five derivatives acting on them respectively. The background dynamical equations are set up for the system under consideration and the stability of the self accelerating solution is demonstrated in general setting. We extended this study to the general case of the fifth order theory. For spherically symmetric static background, we spell out conditions for suppression of fifth force effects mediated by the galileon field $\pi$. We study the field perturbations in the fixed background and investigate conditions for their causal propagation. We also briefly discuss metric fluctuations and derive evolution equation for matter perturbations in galileon gravity.Comment: 11 pages, no figure, minor clarifications and few refs added, to appear in pr

Frequency of Predisposing Factor of Nausea and Vomiting After Chest Surgery Under General Anaesthesia

Background: Postoperative nausea and vomiting are common and distressing postsurgical symptoms. These symptoms are of particular concern in outpatient surgery because they may require additional direct resources, such as supplies and antiemetic drugs, and may delay discharge. The objective of this study was to measure the frequency of factors which can cause nausea and vomiting under general anaesthesia after chest surgery. Methodology: This descriptive case series evaluated frequency of predisposing factor of nausea and vomiting in patients of anaesthesia department of Gulab Devi Hospital Lahore. Questionnaire is made and patients were asked about their age, fever, previous surgery, NPO status, smoking history and hospital stay. This study included 140 patients with post-operative nausea and vomiting. Results: In this study, 140 patients were taken in which  65 (46.43%) were female and 75 (53.57%) were male. In 140 patient 134 (95.7%) were NPO and 6 (4.3%) were not  NPO, 25 (17.9%) were obese and 115 (82.1%) were not obese, 88 (62.9%) patients were suffering fever and 52 (37.1%) were not suffering fever, 80 (57.1%) were infected and 59 (42.1%) were not infected, 53 (37.9%) patients had previous surgery and 87 (62.1%) had no previous surgery, 94 (67.1%) patients had received nitrous oxide and 46 (32.9%) didn\u27t, 97 (69.3%) received volatile gases and 43 (30.7%) not received, 29 (20.7%) received ketamine and 111 (79.3%) not received, 87 (62.1%) received suxamethonium and 53 (37.9%) not received, 119 (85.0%) received propofol and 21 (15.0%) not received, 110 (78.6%) received naluphine and 28 (20.0%) not received. Out of 140 patients, there were 122 (87.1%) who were suffering from pain and 18 (12.9%) were not. 91 (65.0%) patients had gastric distention and 49 (35.0%) patients didn\u27t. Opioids were given to 34 (24.3%) patients and not given to 106 (75.7%) patient. Conclusion: It is concluded that the nausea and vomiting after surgey under genral anesthesia is due to patient related factors in which most frequent is NPO. Drug related factors include propofol and nalbupin administration. Post operative factors include pain. In whole study of 140 patients, the  most frequent is patient related factor (NPO) other than drug related factors and post-operative factors

Non-small cell lung cancer: disease spectrum and management in a tertiary care hospital

Objectives: To review the spectrum of presentation and the surgical management of Non Small Cell Lung Cancer (NSCLC) and the role of various diagnostic modalities in predicting the post-operative stage and the correlation of the post-operative stage with the chances of recurrence.SETTINGS: The Aga Khan University Hospital, Karachi--a tertiary care referral center in Paksitan.Methods: This is a retrospective study of medical records of all the patients who were managed at the Aga Khan University Hospital (AKUH) between 1988 and 1998. The patients with a diagnosis of lung cancer were identified using the ICD-9-CM coding system and the data was analyzed for patients with NSCLC only.Results: A total of 773 patients were admitted with a diagnosis of lung cancer at AKUH over 10 years period. Out of these 21 (2.71%) underwent staging mediastinoscopy and 20 (2.58%) patients underwent exploratory thoracotomy and biopsy without any resection, as the disease was found to be unresectable. Only 18 (2.32%) patients underwent surgical resection. There were 15 males and 3 females and the mean age was 53 years. Mean duration of symptoms was 12 months and cough and haemoptysis were the main presenting symptoms. Most of the tumors were located on the right side. CT scan and mediastinoscopy were mainly used to stage the disease. Complete surgical resection including en-bloc resection of adjacent structures was attempted, when possible. Median follow up was 24 months and the recurrence rate was 39%. There was no significant correlation between post-op stage and recurrence.CONCLUSION: It is concluded that most of the patients present at the advanced stage and resection is possible only in a small number of patients. The size of primary tumor and local extension should not contra-indicate surgery in patients with negative mediastinal nodes and without distant metastasis as it can be performed safely. All pulmonary lesion in the adults must be thoroughly investigated as early diagnosis and complete resection is the only key to cure and long term survival

Aspects of Scalar Field Dynamics in Gauss-Bonnet Brane Worlds

The Einstein-Gauss-Bonnet equations projected from the bulk to brane lead to a complicated Friedmann equation which simplifies to $H^2 \sim \rho^q$ in the asymptotic regimes. The Randall-Sundrum (RS) scenario corresponds to $q=2$ whereas $q=2/3$ & $q=1$ give rise to high energy Gauss-Bonnet (GB) regime and the standard GR respectively. Amazingly, while evolving from RS regime to high energy GB limit, one passes through a GR like region which has important implications for brane world inflation. For tachyon GB inflation with potentials $V(\phi) \sim \phi^p$ investigated in this paper, the scalar to tensor ratio of perturbations $R$ is maximum around the RS region and is generally suppressed in the high energy regime for the positive values of $p$. The ratio is very low for $p>0$ at all energy scales relative to GB inflation with ordinary scalar field. The models based upon tachyon inflation with polynomial type of potentials with generic positive values of $p$ turn out to be in the $1 \sigma$ observational contour bound at all energy scales varying from GR to high energy GB limit. The spectral index $n_S$ improves for the lower values of $p$ and approaches its scale invariant limit for $p=-2$ in the high energy GB regime. The ratio $R$ also remains small for large negative values of $p$, however, difference arises for models close to scale invariance limit. In this case, the tensor to scale ratio is large in the GB regime whereas it is suppressed in the intermediate region between RS and GB. Within the frame work of patch cosmologies governed by $H^2 \sim \rho^q$, the behavior of ordinary scalar field near cosmological singularity and the nature of scaling solutions are distinguished for the values of $q 1$.Comment: 15 pages, 10 eps figures; appendix on various scales in GB brane world included and references updated; final version to appear in PR

TNM cancer staging: can it help develop a novel staging system for type 2 diabetes?

Abstract: Type 2 diabetes (DM2) constitutes 90%–95% of the diabetes cases and is increasing at an alarming rate in the world. The Centers for Disease Control and Prevention (CDC) esti- mates that more than 29 million people in the United States have diabetes, which often causes mortality from macrovascular complications and morbidity from microvascular complications. Despite these troubling facts, there is currently no widely accepted staging system for DM2 like there is for cancer. TNM oncologic staging has taken a complex condition like cancer and conveyed likelihood of survival in simple alpha-numeric terms that both patients and providers can understand. Oncology is now entering the era of precision medicine where cancer treatment is increasingly being tailored to each patient’s cancer. In contrast, DM2 lacks a staging system and remains a largely invisible disease even though it kills more Americans and costs more to treat than cancer. Is a comparable staging system for DM2 possible? We propose the Diabetes Staging System for DM2 that utilizes macrovascular events, microvascular complications, estimated glomerular filtration rate (GFR), and hemoglobin A1C to stage DM2

A symmetry for vanishing cosmological constant

Two different realizations of a symmetry principle that impose a zero cosmological constant in an extra-dimensional set-up are studied. The symmetry is identified by multiplication of the metric by minus one. In the first realization of the symmetry this is provided by a symmetry transformation that multiplies the coordinates by the imaginary number i. In the second realization this is accomplished by a symmetry transformation that multiplies the metric tensor by minus one. In both realizations of the symmetry the requirement of the invariance of the gravitational action under the symmetry selects out the dimensions given by D = 2(2n+1), n=0,1,2,... and forbids a bulk cosmological constant. Another attractive aspect of the symmetry is that it seems to be more promising for quantization when compared to the usual scale symmetry. The second realization of the symmetry is more attractive in that it is posible to make a possible brane cosmological constant zero in a simple way by using the same symmetry, and the symmetry may be identified by reflection symmetry in extra dimensions.Comment: Talk in the conference IRGAC 2006, 2nd International Conference on Quantum Theories and Renormalization Group in Gravity and Cosmology, Barcelon

Avoidance of future singularities in loop quantum cosmology

We consider the fate of future singularities in the effective dynamics of loop quantum cosmology. Non-perturbative quantum geometric effects which lead to $\rho^2$ modification of the Friedmann equation at high energies result in generic resolution of singularities whenever energy density $\rho$ diverges at future singularities of Friedmann dynamics. Such quantum effects lead to the avoidance of a Big Rip, which is followed by a recollapsing universe stable against perturbations. Resolution of sudden singularity, the case when pressure diverges but energy density approaches a finite value depends on the ratio of the latter to a critical energy density of the order of Planck. If the value of this ratio is greater than unity, the universe escapes the sudden future singularity and becomes oscillatory.Comment: 6 pages, 2 figure

Optimize of LIBS Setup to the Determination of Laser Breakdown Power of Writing Inks

Laser-induced breakdown spectroscopy system (LIBS) had been designed to the determinate of the best ionization laser power for analysis of the writing inks via analysis induced plasma emission. Passively Q-Switched Nd:YAG laser at the fundamental wavelength 1064 nm  with different  energies (60 mJ,80mJ, 100 mJ, 200 mJ, 300mJ, 400mJ and 500 mJ) with (10 ns) pulse duration, the laser beam was focused via converging lens with focal length (100 mm) that generates different power intensity, optical spectrum analysis system used was within (Si-CCD)  array detector, within spectrum range of (200 - 900 nm) with (0.8 nm) optical resolution. Use A4 sheets of commercially available standard white office paper with 2 Ballpoint pens and 1 Gel pen as samples. Show the results that the laser energy (80 mJ) with (  power density, was the best power to generate plasma homogeneous for all component writing inks and ionize it without effect on the paper material. Keywords: LIBS, Laser intensity, Writing inks, White paper, plasma emissions lines, emission line analyses DOI: 10.7176/CPER/61-05 Publication date: July 31st 201

Series Solution of the Multispecies Lotka-Volterra Equations by Means of the Homotopy Analysis Method

The time evolution of the multispecies Lotka-Volterra system is investigated by the homotopy analysis method (HAM). The continuous solution for the nonlinear system is given, which provides a convenient and straightforward approach to calculate the dynamics of the system. The HAM continuous solution generated by polynomial base functions is of comparable accuracy to the purely numerical fourth-order Runge-Kutta method. The convergence theorem for the three-dimensional case is also given