Necessity Of Migration Research Articles

A Secular Resonant Origin for the Loneliness of Hot Jupiters

Abstract Despite decades of inquiry, the origin of giant planets residing within a few tenths of an astronomical unit from their host stars remains unclear. Traditionally, these objects are thought to have formed further out before subsequently migrating inwards. However, the necessity of migration has been recently called into question with the emergence of in situ formation models of close-in giant planets. Observational characterization of the transiting subsample of close-in giants has revealed that “warm” Jupiters, possessing orbital periods longer than roughly 10 days more often possess close-in, co-transiting planetary companions than shorter period “hot” Jupiters, that are usually lonely. This finding has previously been interpreted as evidence that smooth, early migration or in situ formation gave rise to warm Jupiter-hosting systems, whereas more violent, post-disk migration pathways sculpted hot Jupiter-hosting systems. In this work, we demonstrate that both classes of planet may arise via early migration or in situ conglomeration, but that the enhanced loneliness of hot Jupiters arises due to a secular resonant interaction with the stellar quadrupole moment. Such an interaction tilts the orbits of exterior, lower-mass planets, removing them from transit surveys where the hot Jupiter is detected. Warm Jupiter-hosting systems, in contrast, retain their coplanarity due to the weaker influence of the host star’s quadrupolar potential relative to planet–disk interactions. In this way, hot Jupiters and warm Jupiters are placed within a unified theoretical framework that may be readily validated or falsified using data from upcoming missions, such as TESS.

An Approach for Energy Efficient Dynamic Virtual Machine Consolidation in Cloud Environment

Nowadays, as the use of cloud computing service becomes more extensive and the customers welcome this service, an increasing trend in energy consumption and operational costs of these centers may be seen. To reduce operational costs, the providers should decrease energy consumption to an extent that Service Level Agreement (SLA) maintains at a desirable level. This paper adopts the virtual machine consolidation problem in cloud computing data centers as a solution to achieve this goal, putting forward solutions to make the decision regarding the necessity of migration from hosts and finding appropriate hosts as destinations of migration. Using time-series forecasting method and Double Exponential Smoothing (DES) technique, the proposed algorithm predicts CPU utilization in near future. It also proposes an optimal equation for the dynamic lower threshold. Comparing current and predicted CPU utilization with dynamic upper and lower thresholds, this algorithm identifies and categorizes underloaded and overloaded hosts. According to this categorization, migration then occurs from the hosts that meet the necessary conditions for migration. This paper identifies a certain type of hosts as “troublemaker hosts”. Most probably, the process of prediction and decision making regarding the necessity of migration will be disrupted in the case of these hosts. Upon encountering this type of hosts, the algorithm adopts policies to modify them or switch them to sleep mode, thereby preventing the adverse effects caused by their existence. The researchers excluded all overloaded, prone-to-be-overloaded, underloaded, and prone-to-be-underloaded hosts from the list of suitable hosts to find suitable hosts as destinations of migration. An average improvement of 86.2%, 28.4%, and 87.2% respectively for the number of migrations of virtual machines, energy consumption, and SLA violation is among the simulation achievements of this algorithm using Clouds tool.

TECHNICAL EDUCATION AND MIGRATION IN TIRIKI, WESTERN KENYA, 1902–1987

[A]ttention should be directed towards agriculturally-oriented or ruraloriented school activity and curriculum content as a means of stemming rural-urban migration as well as increasing agricultural activity in the long run. 1 This is one of the latest additions to a stream of policy advice to the Kenyan authorities that stretches back to the earliest phase of colonial control at the beginning of the 20th century, and has parallels almost everywhere in Africa.2 However, experience of rural education experiments throughout the Third World has generally been disappointing,3 and particularly with respect to the objective of providing an education that would be directly valuable to those living and working in rural areas, and thus reduce the necessity for migration out of rural areas in order to benefit from whatever skills are acquired in school. While the nature and causes of the problems of establishing rural education in Africa have been widely discussed in general terms, the longer term impacts of specific training and schooling policies in particular localities remain obscured by the range of local contexts in which rural education initiatives have been applied. In particular in Kenya, a contrast may be made between areas with a relatively dynamic rural economy, such as the settler areas of the White Highlands in the colonial economy and Central Province or parts of Rift Valley Province since independence, and the more depressed regions, the 'reserves' in the colonial period, Nyanza and Western

The Flight of Two Thousand Marked Male Mediterranean Fruit Flies (Ceratitis Capitata Wied.)

Mally (1, p. 8) Entomologist for the Eastern Province, Cape Colony, South Africa, discusses the migration of the adult Mediterranean fruit fly as follows: “There is no evidence to show how far the adults will travel in their search for food. Some observers think they migrate but very little, citing instances where well-kept premises have been fairly free although in close proximity to neglected and badly infested ones. Under such conditions there is no necessity for migration, ample food-supply being already at hand. There is no clear evidence to show how they get to new orchards on farms where fruit trees have never been grown before. Men who have laid out new orchards say that the ’maggot’ was in evidence the first time the trees came into bearing. * * * It is a popular belief that the flies come in from the veld. The most unrelenting search has failed to demonstrate their presence in bush or veld 500 yards from an orchard.”