204 research outputs found

    Historical impact of technological change on the US mass media advertising expenditure

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    Historically, the U.S. advertising industry has been experiencing enormous movements as a result of rapid advances in the media technology and the business cycle. In this paper, we study the historical behavior of the U.S. advertising industry, correcting for inflation. We find that the introduction of new media cause structural breaks in the mean growth rates of advertising expenditure for the incumbent media. In addition, we find that random components of media advertising spending follow a long-term equilibrium where the cross-elasticities across newer and older media can show substitution or complementarity patterns depending on the type of audience. We examine the influence of the economic conditions on the aggregated advertising expenditure, and on each media spending. We also measure the impact of the recent takeoff in mobile advertising

    Meteorological and hydrological drought hazard, frequency and propagation analysis : a case study in southeast Australia

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    Study region: Southeast Australia.Study focus: We investigated meteorological and hydrological drought characteristics using Standardized Precipitation Index (SPI), Standardized Streamflow Index (SSFI) and Effective Drought Index (EDI). Drought Hazard Index (DHI) was derived based on the probability of drought occurrence and Thiessen polygons using SPI/EDI, whereas Drought Frequency Index (DFI) was derived based on number of drought events, and data length using SPI, EDI, and SSFI. The modified Mann-Kendall test was applied to detect trends in streamflow data and hydrological droughts. Furthermore, correlation between meteorological and hydrological drought indices for different timesteps was assessed through Pearson's and Spearman's rank correlation analysis. Finally, the drought propagation time (DPT) from meteorological to hydrological drought was estimated by 'theory of run.'New hydrological insights for the region: Our major findings include: (i) The spatial coverage of DHI and DFI, based on SPI/EDI, illustrate that mainly south and coastal regions of the study area are the most 'drought-prone' (ii) A considerable proportion of streamflow stations shows a significant trend of decrease in annual streamflow, with the most dominant year of abrupt change is 1996; (iii) Hydrological droughts are increasing in the study area; (iv) Performance of EDI with SSFI is found to be better than SPI at 3-month timestep; and (v) DPT can be found using 'theory of run' however, defined DPT cannot be directly applied to other regions

    A bibliometric analysis of drought indices, risk, and forecast as components of drought early warning systems

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    In this study, we apply a bibliometric analysis to characterize publication data on droughts, mainly focusing on drought indices (DIs), drought risk (DR), and drought forecast (DF). Data on publications on these selected topics were obtained through the Scopus database, covering the period from 1963 to June 2021. The DI-related publications, based on meteorological, soil moisture, hydrological, remote sensing, and composite/modeled Dis, accounted for 57%, 8%, 4%, 29%, and 2% of the scientific sources, respectively. DI-related studies showed a notable increase since the 1990s, due perhaps to a higher number of major droughts during the last three decades. It was found that USA and China were the two leading countries in terms of publication count and academic influence on the DI, DR, and DF studies. A network analysis of the country of residence of co-authors on DR and DF research highlighted the top three countries, which were the USA, China, and the United Kingdom. The most productive journal for the DI studies was found to be the International Journal of Climatology, whereas Natural Hazards was identified as the first-ranked journal for the DR and DF studies. In relation to individual researchers, Singh VP from the USA was found to be the most prolific author, having the greatest academic influence on DF study, whereas Zhang Q from China was identified as the most productive author on DR study. This bibliometric analysis reveals that further research is needed on droughts in the areas of risk management, water management, and drought management. This review maps trends of previous research in drought science, covering several important aspects, such as drought indices, geographic regions, authors and their collaboration paths, and sub-topics of interest. This article is expected to serve as an index of the current state of knowledge on drought warning systems and as guidance for future research needs

    Review of rainwater harvesting research by a bibliometric analysis

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    This study presents a review of recent rainwater harvesting (RWH) research by a bibliometric analysis (based on performance analysis and science mapping method). Following the inclusion/exclusion criteria, a total of 3226 publications were selected for this bibliometric analysis. From the selected publications, the top journals were identified according to number of publications and number of citations, as well as the authors with the highest number of publications. It has been found that publication rate on RWH has been increasing steadily since 2005. Water (MDPI) journal has published the highest number of publications (128). Based on the literature considered in this review, the top five authors are found as Ghisi, E., Han, M., Rahman, A., Butler, D. and Imteaz, M.A. in that order. With respect to research collaborations, the top performing countries are USA–China, USA–Australia, USA–UK, Australia–UK and Australia–China. Although, the most dominant keywords are found to be ‘rain’, ‘rainwater’, ‘water supply’ and ‘rainwater harvesting’, since 2016, a higher emphasis has been attributed to ‘floods’, ‘efficiency’, ‘climate change’, ‘performance assessment’ and ‘housing’. It is expected that RWH research will continue to rise in future following the current trends as it is regarded as a sustainable means of water cycle management

    Peaks-over-threshold based regional flood frequency analysis using regularised linear models

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    Regional flood frequency analysis (RFFA) is widely used to estimate design floods in ungauged catchments. Most of the RFFA techniques are based on the annual maximum (AM) flood model; however, research has shown that the peaks-over-threshold (POT) model has greater flexibility than the AM model. There is a lack of studies on POT-based RFFA techniques. This paper presents the development of POT-based RFFA techniques, using regularised linear models (least absolute shrinkage and selection operator, ridge regression and elastic net regression). The results of these regularised linear models are compared with multiple linear regression. Data from 145 stream gauging stations of south-east Australia are used in this study. A leave-one-out cross-validation is adopted to compare these regression models. It has been found that the regularised linear models provide quite accurate flood quantile estimates, with a median relative error in the range of 37 to 47%, which outperform the AM-based RFFA techniques currently recommended in the Australian Rainfall and Runoff guideline. The developed RFFA technique can be used to estimate flood quantiles in ungauged catchments in the study region

    Investigation on the Effects of 12 Days Intensive Competition on Some Blood Parameters of Basketball Players

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    The aim of this study is  to investigate the effect of intensive basketball competitions (10 official basketball games in 12 days intensive competition period) on blood parameters of basketball players. Blood samples were taken from the basketball players of the university team. The players were training regularly and they had no regular health problems. The average age of the players was 22,80 ± 3,20 years and the average height was 185,83 ± 7,57 cm. This study was performed on 10 volunteer basketball players. Blood samples were taken before (24 hours), after (24 hours) and during the intensive competitions. Descriptive statistics (mean and standard deviation) were applied to the data, Wilcoxon two realized sample test was used to compare the values before and after the competition period. When comparing the blood values before and after the competition period, there was significant increase in prevalence of Fe, albumin, AST, ALT, LDL, HDL, MCH, MCHC and the values of UIBC, creatinine, HCT and MPV were significantly low before the competition; (P <0.05).The findings show that the physiological characteristics of basketball players are influenced by intensive competitions. In the literature, the physiological effects of regular and single-session exercises have been investigated in many studies. However, the data about the physiological effects of intensive competition periods are rather limited. A better understanding of these influences will guide the event organizers and coaches to plan the competitions and it will facilitate the preparation of the sportsmen for this intensive competition periods

    Phytochemical compositions, antioxidant properties, enzyme inhibitory effects of extracts of four endemic Lathyrus L. taxa from TĂŒrkiye and a taxonomic approach

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    ABSTRACT Lathyrus is an economically important genus, with different parts of some species used as foodstuff or animal feed. In this study, phytochemical compositions and bioactivities of Lathyrus brachypterus var. brachypterus, L. brachypterus var. haussknechtii, L. nivalis subsp. sahinii and L. tefennicus taxa which are endemic to TĂŒrkiye were investigated. Total phenolic and flavonoid contents (TPC, TFC) of methanolic extracts were detected. Then, phytochemical compositions, antioxidant features (radical scavenging (DPPH: 1,1-diphenyl-2-picrylhydrazyl, ABTS: 2,2â€Č-azino-bis(3 ethylbenzothiazoline) 6 sulfonic acid), reducing power (FRAP:Ferric ion reducing antioxidant power, CUPRAC:Cupric ion reducing antioxidant capacity), metal chelating activity (MCA), and the phosphomolybdenum assays (PDA)) and enzyme inhibitory properties of the extracts were also determined. The highest values were found at L. brachypterus var. brachypterus for TPC, L. brachypterus var. haussknechtii for TFC. The highest antioxidant properties were seen in extracts of L. brachypterus var. brachypterus in DPPH, ABTS, FRAP, CUPRAC and PDA assays, while in extract of L. nivalis subsp. sahinii in MCA. The highest enzyme inhibitory activity was found in extract of L. brachypterus var. brachypterus in tyrosinase and glucosidase assays, while in extracts of L. nivalis subsp. sahinii in AChE (acetylcholinesterase), BChE (butyrylcholinesterase) and amylase. Finally, a taxonomic evaluation was made by considering the phytochemicals

    The Effect of Gadolinium and Lanthanum on the Mortality of Daphnia magna

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    Rare earth elements (REEs) have been recently identified as emergent contaminants because of their numerous and increasing applications in technology. The impact of REEs on downstream ecosystems, notably aquatic organisms, is of particular concern, but has to date been largely overlooked. The purpose of this study were to generate toxicological information regarding these poorly studied Gadolinium and Lanthanum elements to determine the current risk associated with these elements. The results of this work indicate a notable D. magna mortality in high concentration of La and Gad. The findings from our study also indicate that Gad is more toxic than La. Due to this mortality effect of La and Gad to D. magna, it will be important for the ensuring continuity of the ecosystem to monitor especially aquatic environments and to treat them with appropriate treatment methods from contaminated environments
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