Observational properties of a kink unstable coronal loop

Aims. Previous work on the dynamics of the kink instability has concentrated on the evolution of the magnetic field and associated current sheets. Here we aim to determine the observational consequences of the kink instability in short coronal loops, particularly what images TRACE would record of such an instability. This paper concentrates on the internal m = 1 mode where the kink structure of the instability may not be apparent from the global field shape. This is most relevant to the observation of active region brightenings and coronal bright points. Methods. An existing fluid code was modified to include the TRACE temperature response function in order to calculate temporally and spatially averaged, line of sight images in the 171, 195 and 284 Å band passes for straight, kink unstable flux tubes. Results. Two new fluid effects of the kink instability are discovered: the circular enhancement of the density at the foot points and the appearance of a low density band running across the flux tube. The second of these effects is shown to be imagable by TRACE and hence would be a good candidate observational signature for an internal m = 1 kink unstable loop

Limiting Family Size Through the Sufficient Provision of Basic Necessities and Social Services: The Case of Pasay, Eastern Samar, and Agusan Del Sur

The socio-economic quandaries of rapid population growth and poverty have always been coupled. It is evident that the poorest households are those who have larger family size. Consequently, these households have to support more people with fewer resources, making the family live a life of inherited poverty. With this, the state has been on the pursuit of looking for solutions such as the Reproductive Heath (RH) Bill to address rapid population growth and eventually poverty. However, the Roman Catholic Church (RCC) condemns the RH Bill because it is contradictory to Catholic principles. For this reason, we will explore other possibilities to limit family size by highlighting whether the availability of water, electricity, decent housing, sustainable income, employment, and other welfare enhancing programs limits family size. By showing whether the provision of these basic sustenance affects family size via the Maximum Likelihood Estimation (MLE) procedure, it is then possible to propose an alternative solution other than the use of contraceptives. Likewise, the government can improve on its socio-economic policies that will address the problem of overpopulation. Results have shown that Pasay, Eastern Samar, and Agusan Del Sur responded differently to various stimuli such as living conditions, educational attainment, employment status, as well as government-funded programs among others insofar as population dynamics is concerned. This suggests a need to peer into the distinction of each region’s socioeconomic context and underlying psyche. The milieu within which an individual resides may greatly influence his rational calculus and decision-making process. Also, beyond tailoring-fitting population control programs, there is also a need to calibrate policies based on relevant socioeconomic, political, and cultural nuances each region may possess

The triggering of MHD instabilities through photospheric footpoint motions

The results of 3D numerical simulations modelling the twisting of a coronal loop due to photospheric vortex motions are presented. The simulations are carried out using an initial purely axial field and an initial equilibrium configuration with twist, . The non-linear and resistive evolutions of the instability are followed. The magnetic field is twisted by the boundary motions into a loop which initially has boundary layers near the photospheric boundaries as has been suggested by previous work. The boundary motions increase the twist in the loop until it becomes unstable. For both cases the boundary twisting triggers the kink instability. In both cases a helical current structure wraps itself around the kinked central current. This current scales linearly with grid resolution indicating current sheet formation. For the cases studied 35-40% of the free magnetic energy is released. This is sufficient to explain the energy released in a compact loop flare

Industry Career Guide: Manufacturing

Manufacturing sector in the Philippines has one of the largest contributions to the growth of the economy. Throughout the years, starting from the 1970s, the manufacturing sector has been one of the driving forces behind the country’s growth. It has proven its importance in the economy because of benefits such as employment generation and technological innovation

Can the Provision of Social Services Limit Family Size? The Case of Pasay, Eastern Samar, and Agusan Del Sur

Rapid population growth is deemed by economists as one of the root causes of the Philippines’ underdevelopment, economic stagnation, resource depletion, and high crime rate, among others. According to Todaro and Smith (2008), it gives rise to poverty since economic growth cannot outpace and sustain the rate at which population expands

Ideal kink instability of a magnetic loop equilibrium

The force-free coronal loop model by Titov & D\'emoulin (1999} is found to be unstable with respect to the ideal kink mode, which suggests this instability as a mechanism for the initiation of flares. The long-wavelength ($m=1$) mode grows for average twists \Phi\ga3.5\pi (at a loop aspect ratio of $\approx$ 5). The threshold of instability increases with increasing major loop radius, primarily because the aspect ratio then also increases. Numerically obtained equilibria at subcritical twist are very close to the approximate analytical equilibrium; they do not show indications of sigmoidal shape. The growth of kink perturbations is eventually slowed down by the surrounding potential field, which varies only slowly with radius in the model. With this field a global eruption is not obtained in the ideal MHD limit. Kink perturbations with a rising loop apex lead to the formation of a vertical current sheet below the apex, which does not occur in the cylindrical approximation.Comment: Astron. Astrophys. Lett., accepte

Retesting in Selection: A Meta-Analysis of Practice Effects for Tests of Cognitive Ability

Previous studies indicate that as many as 25-50% of applicants in organizational and educational settings are retested with measures of cognitive ability. Researchers have shown that practice effects are found across measurement occasions such that scores improve when these applicants retest. This study uses meta-analysis to summarize the results of 50 studies of practice effects for tests of cognitive ability. Results from 107 samples and 134,436 participants revealed an adjusted overall effect size of .26. Moderator analyses indicated that effects were larger when practice was accompanied by test coaching, and when identical forms were used. Additional research is needed to understand the impact of retesting on the validity inferences drawn from test scores

Characterising the disintegration properties of tablets in opaque media using texture analysis.

Tablet disintegration characterisation is used in pharmaceutical research, development, and quality control. Standard methods used to characterise tablet disintegration are often dependent on visual observation in measurement of disintegration times. This presents a challenge for disintegration studies of tablets in opaque, physiologically relevant media that could be useful for tablet formulation optimisation. This study has explored an application of texture analysis disintegration testing, a non-visual, quantitative means of determining tablet disintegration end point, by analysing the disintegration behaviour of two tablet formulations in opaque media. In this study, the disintegration behaviour of one tablet formulation manufactured in-house, and Sybedia Flashtab placebo tablets in water, bovine, and human milk were characterised. A novel method is presented to characterise the disintegration process and to quantify the disintegration end points of the tablets in various media using load data generated by a texture analyser probe. The disintegration times in the different media were found to be statistically different (P<0.0001) from one another for both tablet formulations using one-way ANOVA. Using the Tukey post-hoc test, the Sybedia Flashtab placebo tablets were found not to have statistically significant disintegration times from each other in human versus bovine milk (adjusted P value 0.1685).This work was made possible through the generous support of the Saving Lives at Birth partners: the United States Agency for International Development (USAID), the Government of Norway, the Bill & Melinda Gates Foundation, Grand Challenges Canada and the UK Department for International Development (DFID).This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S0378517315002392#

Large Scale Proactive Power-Quality Monitoring: An Example from Australia

In Australia and many other countries, distribution network service providers (DNSPs) have an obligation to their customers to provide electrical power that is reliable and of high quality. Failure to do so may have significant implications ranging from financial penalties theoretically through to the loss of a license to distribute electricity. In order to ensure the reliability and quality of supply are met, DNSPs engage in monitoring and reporting practice. This paper provides an overview of a large long-running power-quality monitoring project that has involved most of Australia\u27s DNSPs at one time or another. This paper describes the challenges associated with conducting the project as well as some of the important outcomes and lessons learned. A number of novel reporting techniques that have been developed as part of the monitoring project are also presented. A discussion about large-volume data management, and issues related to reporting requirements in future distribution networks is included

Numerical simulations of kink instability in line-tied coronal loops

The results from numerical simulations carried out using a new shock-capturing, Lagrangian-remap, 3D MHD code, Lare3d are presented. We study the evolution of the m=1 kink mode instability in a photospherically line-tied coronal loop that has no net axial current. During the non-linear evolution of the kink instability, large current concentrations develop in the neighbourhood of the infinite length mode rational surface. We investigate whether this strong current saturates at a finite value or whether scaling indicates current sheet formation. In particular, we consider the effect of the shear, defined by where is the fieldline twist of the loop, on the current concentration. We also include a non-uniform resistivity in the simulations and observe the amount of free magnetic energy released by magnetic reconnection