Exit from Inflation with a First-Order Phase Transition and a Gravitational Wave Blast

In double-field inflation, which exploits two scalar fields, one of the fields rolls slowly during inflation whereas the other field is trapped in a meta-stable vacuum. The nucleation rate from the false vacuum to the true one becomes substantial enough that triggers a first order phase transition and ends inflation. We revisit the question of first order phase transition in an "extended" model of hybrid inflation, realizing the double-field inflationary scenario, and correctly identify the parameter space that leads to a first order phase transition at the end of inflation. We compute the gravitational wave profile which is generated during this first order phase transition. Assuming instant reheating, the peak frequency falls in the $1$ GHz to $10$ GHz frequency band and the amplitude varies in the range $10^{-11}\lesssim \Omega_{\rm GW} h^2 \lesssim 10^{-8}$, depending on the value of the cosmological constant in the false vacuum. The signature could be observed by the planned Chongqing high frequency gravitational probe. For a narrow band of vacuum energies, the first order phase transition can happen after the end of inflation via the violation of slow-roll, with a peak frequency that varies from $1$ THz to $100$ THz. For smaller values of cosmological constant, even though inflation can end via slow-roll violation, the universe gets trapped in a false vacuum whose energy drives a second phase of eternal inflation. This range of vacuum energies do not lead to viable inflationary models, unless the value of the cosmological constant is compatible with the observed value, $M\sim 10^{-3}$ eV.Comment: v1: 15 pages, 8 Figures; v2: typos corrected;v3: matched the PLB versio

Growth, profitability and savings of quoted public limited companies 1964-70

This study by extending an earlier study by Haq and Baqai (1967) on growth, profitability and savings of companies quoted on the Karachi Stock Exchange analysis movements of these key variables and identifies key factors and events which explain them for the entire period of the 1960s

Rescuing Single Field Inflation from the Swampland

The difficulty of building metastable vacua in string theory has led some to conjecture that, in the string theory landscape, potentials satisfy $\left|\nabla V/V\right|\geq c\sim \mathcal{O}(1)$. This condition, which is supported by different explicit constructions, suggests that the EFTs which lead to metastable de-Sitter vacua belong to what is dubbed as swampland. This condition endangers the paradigm of single field inflation. In this paper, we show how scalar excited initial states cannot rescue single field inflation from the swampland, as they produce large local scalar non-gaussianity, which is in conflict with the Planck upper bound. Instead, we demonstrate that one can salvage single field inflation using excited initial states for tensor perturbations, which in this case produce only large flattened non-gaussianity in the tensor bispectrum. We comment on the possible methods one can prepare such excited initial conditions for the tensor perturbations.Comment: v1: 8 pages double columns, no figures; v2: references added, matched the PLB versio

The impact of socio-economic factors on small business success

Small enterprises play a vital role in economic development as they can provide the economy with efficiency, innovation, competition and employment. Entrepreneurs are responsible for the success of their businesses and have to face up with definite challenges in doing so. To know what constitute critical determinants of small business success data were collected from 60 randomly selected respondents in the Dera Ismail Khan district, Khyber Pakhtunkhawa, Pakistan, who were administered with structured questionnaires. Regression analyses of the findings showed the positive and significant impact factors of investment, entrepreneurial experience, business profile and culture with R2=0.638 and F= 11.222. The provision of ample opportunities to develop skills for business enhancement is suggested as the rational way forward

Development of D-Statcom in hardware in the loop system for voltage SAG mitigation

The problem of power quality (PQ) is of utmost concern today. The widespread use of electronic equipment such as adjustable speed drive (ASD), programmable logic controller (PLC), information technology equipment in power electronics applications such as energy-efficient lighting brings about a complete change in the nature of the electrical load. These loads are simultaneously major causes and major victims due to power quality problems. The most common types of power quality problems are voltage drops. The main causes of the voltage drop are due to a short circuit in the system, a switching operation, the starting of the large motor, a sudden increase in line loads, electrical fault on utility power lines caused by an animal, trees or other objects in contact with power lines. Therefore, this project is about to develop a Distributed Static Compensator (D-STATCOM) for voltage sag mitigation in hardware in the loop (HIL) with phase shift control technique for maintaining the bus bar-load voltage. It is because the intermittent switching of heavy loads results in voltage sag in the distribution line. The distribution line 400V and the D-STATCOM are modeled using MATLAB-SIMULINK software. In this work, the 6-pulse D-STATCOM configuration with IGBT has been designed. The HIL was develop using the low-cost microcontrollers which are the Arduino Mega 2560 and Raspberry Pi Type B2 with high accuracy response for high speed communication on mimic the real time response. In order to run the D-STATCOM in HIL and test the mitigation of sag, software design is first carried out to illustrate the use of D-STATCOM in mitigating voltage sag in a distribution line. The simulation results for software design proved that the D-STATCOM is capable of mitigating voltage sag as well as improving power quality of a system and the voltage sag 20% was corrected from 200V to normal voltage 245V. The D-STATCOM that has been modeled successfully and able to mitigate the voltage sag by using D-STATCOM in (HIL). At last the results have been analyzed and compared with the results which get in software

The impact of teacher wages on the performance of students: evidence from PISA

Teacher profile and characteristics are not weightless because student achievements are heavily teacher dependent. In this detailed and in-depth research, the impact of teacher wages on students’ achievement was assessed in different ways by using different measuring sticks; starting salary, salary after 15 year of experience, salary per hour of net teaching time and salary ratio to GDP per capita and by using country scores, of 15 year old pupil enrolled in lower secondary school, in OECD member countries. For this propose PISA 2000, 2003 and 2006 survey data of students’ scores were used. The independent variables “wages” was regressed on the dependent variable “students total mean country score”. The results of these analyses gave an indication that there is a positive impact of teacher wages on students’ performance.characteristics, profile, qualities, impact, teacher, learning, achievements, performance, student, salary, wages, gender, PISA, OECD

Solving Pakistan's Poverty Puzzle: Whom Should We Believe? What Should We Do?

Understanding Pakistan’s economic performance has never been easy. Its capacity to generate impressive rates of economic growth in the 1960s and 1980s with low levels of savings, investment and very poor human development indicators confounded its critics. Indeed during the overall period 1960–1990 Pakistan’s growth performance would place it in the top ten countries in the world. This made an eminent economist Professor Richard Eckaus remark, “Pakistan is a puzzle, a miracle of levitation. With one of the lowest domestic savings rate in Asia, its economy has performed quite creditably. Since we do not believe in miracles, we have to wonder whether the capital inflows that have sustained this growth will last”.1 Unfortunately they did not. Pakistan’s growth rate in the 1990s came tumbling down, the result of a number of factors of which a decline in capital inflows also played a significant part. If Pakistan’s growth performance has been in part difficult to justify then understanding or explaining changes and wide fluctuations in its poverty levels has posed even a more challenging task. Pakistan has witnessed over the last three decades periods of high economic growth, as in the 1960s, accompanied with increasing poverty levels, periods of low economic growth, as in the 1970s, accompanied by reductions in poverty levels, periods of high economic growth leading to a decline in poverty as in the 1980s and periods of low economic growth as in the 1990s accompanied by as we shall see by increasing poverty levels.

International Labor Migration and Its Implications in the APEC Region

This paper identifies some of the key issues confronting the Asia-Pacific member-economies that arise from the discussions in the APEC forum. A brief review of existing labor flows within the APEC regions is presented. A discussion on how globalization and trade liberalization will impact on the international movements of labor in the APEC regions is also included.globalization, trade sector, liberalization, APEC