Search results for " Sam"
showing 10 items of 1096 documents
A Colorimetric Membrane-Based Sensor with Improved Selectivity towards Amphetamine
2021
Due to their simplicity, speed and low cost, chemical spot tests are increasingly demanded for the presumptive identification of illicit drugs in a variety of contexts such as point-of-care assistance or prosecution of drug trafficking. However, most of the colorimetric reactions used in these tests are, at best, drug class selective. Therefore, the development of tests based on chemical reactions with improved discrimination power is of great interest. In this work, we propose a new colorimetric assay for amphetamine (AMP) based on its reaction with solutions of alkaline gold bromide to form an insoluble yellow–orange derivative. The resulting suspensions are then filtered onto nylon membr…
Simultaneous determination of traditional and emerging illicit drugs in sediments, sludges and particulate matter
2015
An analytical method for determining traditional and emerging drugs of abuse in particulate matter, sewage sludge and sediment has been developed and validated. A total of 41 drugs of abuse and metabolites including cocainics, tryptamines, amphetamines, arylcyclohexylamines, cathinones, morphine derivatives, pyrrolidifenones derivatives, entactogens, piperazines and other psychostimulants were selected. Samples were ultrasound extracted with McIlvaine buffer and methanol, and the extracts were cleaned up by solid phase extraction (SPE) using Strata-X cartridges. Drugs were eluted using methanol and methanol-dichloromethane and determined by liquid chromatography tandem mass spectrometry. Th…
Medical Academic Speech. A Corpus-based Investigation of Same-Speaker Most Frequent Content Key Word Repetition in Non-Native English Discourse
2016
Studies on repetition in ELF interactions have been carried out in several domains, but medical academic discourse still remains under-researched. This paper explores same-speaker repetition in a 31,153-word corpus of lectures included in the 100,135-word medical section of the 1 million-word ELFA (English as a Lingua Franca in Academic Settings) corpus. More specifi cally, the corpus was searched for the most frequent same-speaker content key word repetition and corresponding functions, with both immediate and delayed repetition being scrutinized. The results confi rmed the initial hypothesis according to which same-speaker repetition was expected to be pervasive in the data, not only as a…
Tardigrades of Finland: new records and an annotated checklist
2020
Species checklists are powerful and important tools of communication between taxonomists and applied environmental biologists, which in turn lead to well-planned and successful conservation strategies and ecological studies. Despite this, only recently the interest on compiling systematic checklists is growing among taxonomists who study tardigrades—micrometazoans that inhabit almost every habitat worldwide. As the Finnish records of tardigrades (a.k.a. water bears) species are incomplete, outdated and no checklist has ever been compiled for this country, an easy-to-consult checklist is here reported. This checklist covers all Finnish tardigrade taxa identified in the past and in the 13 sam…
The invasion history of Elodea canadensis and E. nuttallii (Hydrocharitaceae) in Italy from herbarium accessions, field records and historical litera…
2022
AbstractWe analysed the invasion history of two North American macrophytes (Elodea canadensis and E. nuttallii) in Italy, through an accurate census of all available herbarium and field records, dating between 1850 and 2019, and a rich literature collection describing the initial introduction and naturalisation phase that supports the results obtained by the occurrence records. Elodea canadensis arrived in Italy before 1866 and had two invasion phases, between the 1890s and 1920s and between the 1990s and 2000s; E. nuttallii, probably arrived in the 1970s, started invading in 2000 and the invasion is still ongoing. Botanical gardens and fish farming played a crucial role in dispersal and na…
Complementarities in innovation strategy: do intangibles play a role in enhancing firm performance?
2017
This article assesses the role of investments in intangible capital and their potential complementarities as a way to improve firm productivity. We focus on the three intangible resources that, according to the literature, have the greatest strategic importance: research and development (R & D), advertising, and human capital. To test our hypotheses, we use a large sample of Spanish manufacturing firms and consider estimates of total factor productivity through a generalized method of moments approach. Our results show evidence of complementarities between R & D and advertising investments and between advertising and human capital. However, they are not conclusive in the case of R & D and h…
The real exchange rate in the long run: Balassa-Samuelson effects reconsidered
2017
Historical data for over hundred years and 14 countries is used to estimate the long-run effect of productivity on the real exchange rate. We find large variations in the productivity effect across four distinct monetary regimes in the sample period. Although the traditional Balassa-Samuelson model is not consistent with these results, we suggest an explanation of the results in terms of contemporary variants of the model that incorporate the terms of trade mechanism. Specifically we argue that changes in trade costs over time may affect the impact of productivity on the real exchange rate over time. We undertake simulations of the modern versions of the Balassa-Samuelson model to show that…
Export markets: substitutes, complements, or independent?
2020
Using a large sample of export transactions in Spain over the period 2010–2017, we explore whether firms treat export markets as substitutes, complements, or independent. We find that an exogenous ...
The monitoring role of female directors over accounting quality
2017
Recent research in accounting suggests female directors exert more stringent monitoring over the financial reporting process than their male counterparts. However, an emerging literature in finance and economics provides mixed findings and questions whether females in leadership roles significantly differ from their male counterparts. Building on this literature, we re-examine the link between the presence of female directors, gender biases, and financial statements quality. Using a large sample of UK firms we find that a larger percentage of women among independent directors is significantly associated with lower earnings management practices. However, we show that this relation disappears…
Do foreign workers reduce trade barriers? Microeconomic evidence
2015
This paper provides evidence that foreign workers reduce firms' trade costs and thus increase the probability that firms export. This informs both the literature on trade costs and the microeconomic literature on firms' export behaviour. We identify the nationality of each worker in a large sample of German establishments, and relate this to the exporting behaviour of these establishments. We allow for the possible endogeneity of an establishment's workforce by instrumenting the share of foreign workers with the regional distribution of foreign workers in the wider labour market. We find a significant effect of worker nationality on exporting which is not driven by the industrial, occupatio…