The identification of trends in outgassing technology

A large amount of chemical analysis data involving identification of outgassing products from spacecraft, experiment modules, and support equipment accumulated at the Goddard Space Flight Center over the past ten years were reduced to a computer compatible format and subjected to a variety of relevant program operations. From these data a list of the most troublesome outgassing species were compiled and several useful and interesting materials' correlations were developed. The frequency of occurrence totals show that in aerospace program, di(2-ethyl hexyl) phthalate (DEHP) is the most often found individual species in outgassing samples and that esters are the leading generic class of compounds. The effectiveness of this data bank was demonstrated by the good correlations between materials and their outgassing products for solar panel bakeouts and cable bakeouts. However, trends in frequency of occurrence of many compounds were demonstrated where no correlation could be established. In the case of the class of compounds called aliphatic hydrocarbons, it is shown that the number of instances of significant outgassing due to these materials is increasing

De-Trending Time Series for Astronomical Variability Surveys

We present a de-trending algorithm for the removal of trends in time series. Trends in time series could be caused by various systematic and random noise sources such as cloud passages, changes of airmass, telescope vibration or CCD noise. Those trends undermine the intrinsic signals of stars and should be removed. We determine the trends from subsets of stars that are highly correlated among themselves. These subsets are selected based on a hierarchical tree clustering algorithm. A bottom-up merging algorithm based on the departure from normal distribution in the correlation is developed to identify subsets, which we call clusters. After identification of clusters, we determine a trend per cluster by weighted sum of normalized light-curves. We then use quadratic programming to de-trend all individual light-curves based on these determined trends. Experimental results with synthetic light-curves containing artificial trends and events are presented. Results from other de-trending methods are also compared. The developed algorithm can be applied to time series for trend removal in both narrow and wide field astronomy.Comment: Revised version according to the referee's second revie

COMMON STOCHASTIC TRENDS IN INTERNATIONAL STOCK MARKETS: TESTING IN AN INTEGRATED FRAMEWORK

In this paper we analyze the implications for the identification of common stochastic trends among stock price indices of using data transformed on a ”real dollar” basis. By applying a “general” VAR model where all the relevant variables (stock indices, consumer price indices and the exchange rate) are included, we show that the expected results from the cointegration analysis differ substantially. In particular it is shown that if four common stochastic trends drive the system then cointegration between the indices transformed in nominal dollars should be the relevant test while the use of their “real dollars equivalent” is superfluous. In cases where three common stochastic trends exist then a reasonable specification of the model would imply that the Purchasing Power Parity condition accounts for one of them while the second one relates to a cointegrating relation between the stock indices in nominal domestic currency terms. We apply the testing methodology developed by Johansen (1992a, 1995a, 1997) and extended by Paruolo (1996) and Rahbek et al. (1999) to examine the presence of I(2) and I(1) components in a multivariate context using monthly data for the US, UK, Germany and Japan for the period 1980 – 2000. Four possible economic scenarios were considered in a bivariate setting and two of them were found to be statistically supported. By imposing linear restrictions on each cointegrating vector as suggested by Johansen and Juselius (1994), the order and rank conditions for statistical identification are satisfied while the test for economic identification was not significant for each bilateral case, namely US-UK, US-Germany, US-Japan. The main findings suggest that the policy to transform the data into a “real” dollar basis, which is often encountered in the literature, lacks empirical support. Furthermore, the stability results indicate that cointegration was established in the early 1990s which implies that some form of policy coordination between the G-7 countries was implemented in the aftermath of the October 1987 crisis.International stock markets, I(2) cointegration analysis, commom trends, identification, purchasing

Auditing scholarly journals published in Malaysia and assessing their visibility

The problem with the identification of Malaysian scholarly journals lies in the lack of a current and complete listing of journals published in Malaysia. As a result, librarians are deprived of a tool that can be used for journal selection and identification of gaps in their serials collection. This study describes the audit carried out on scholarly journals, with the objectives (a) to trace and characterized scholarly journal titles published in Malaysia, and (b) to determine their visibility in international and national indexing databases. A total of 464 titles were traced and their yearly trends, publisher and publishing characteristics, bibliometrics and indexation in national, international and subject-based indexes were described

Identification of consumer development trends in a major city: a market-based approach

The subject matter of this article consists in a comparative analysis of key indicators of consumer market development in major cities of various Subjects of the Russian Federation, which are located in the same macro-region, taking the first three places in the regional hierarchy according to the population of the RF Subject territory, comprising the centres of large urban agglomerations and making a significant contribution to the formation of regional indicators of socio-economic development. The article is based on Federal State Statistics Service data on three RF Subjects namely, Perm Krai, Sverdlovsk and Chelyabinsk regions covering the period from 2007 to 2015. The study is based on the analysis, classification and systematisation of the information of theoretical sources and statistical data relating to the study, as well as on the presentation of the author’s approaches and conclusions. Thus, within the framework of the research, the author considers different theoretical approaches to the consumer market and proposes a definition for the consumer market of a major city, taking into account the specifics of its functioning as an element of the economy of the city. With regard to the identification of development trends, in the framework of the study, new indices have been applied, such as “index of concentration of stationary retail establishments”, “index of concentration of non-stationary retail establishments”, “index of concentration of public canteens, snack bars”, “index of concentration of canteens owned by the educational institutions, organisations, industrial enterprises” and “index of concentration of restaurants, cafes, bars”. These indices characterise the degree of concentration of different types of retail establishments and catering establishments within a defined territory. According to the research, all cities included in the scope of the study have been grouped according to the identified consumer market development trends. The author has also developed a number of recommendations for the public authorities and local governments for improving the consumer markets of studied cities

Climatic change controls productivity variation in global grasslands.

Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2-71.2% during 1982-2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms

A 10 year review of the number of bovine dairy holdings and the dairy bovine population on the Maltese Islands

The process of identification and registration of bovines and bovine holdings on the Maltese Islands has been computerised since 2002, with the introduction of the National Livestock Database of Malta. This is a computerised and centralised system which has made collection, management and analysis of data possible. The aims of this paper were to study in detail ten year trends in the number of bovine dairy holdings together with the bovine population on these holdings and to compare these trends with those reported in other European countries. Six trends related to the number of bovine dairy holdings and their bovine population were analysed in the study. The general trends showed that there was a significant decrease in the number of dairy holdings, in the bovine population and in the number of female bovines greater than 2 years of age during the study period. The average herd size and the average number of females greater than 2 years of age on the dairy holdings showed no statistically significant changes. On the other hand, a significant increase in the ratio of female to male bovines was registered on these holdings.peer-reviewe