Hawking Hyphens in Compound Modifiers

The first principle of legal writing is surely its clarity — visible actors (unless the action matters more), uncluttered syntax, and, of course, logical structure. But the little things can matter to clarity, too — such as deliberate punctuation that signifies. In the language of law, in which compound nouns are rife, the reader can feel adrift as to where modifiers end and the noun begins. (Consider government-subsidized health flexible-spending arrangement without those hyphens.) Hyphens help. Whether an author cares to hyphenate the noun is his call; but hyphenating compound modifiers (also called phrasal adjectives, though they may include adverbs — more-abundant paperclips) follows a logic that is worth learning. This essay describes that logic. But its pitch is that legal writing, of all writing disciplines, should practice a deliberate, consistent use of such hyphens, rather than the more-relaxed practice readers see in less-formal writing (whose effects, of course, are usually also less consequential)

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Dispersive liquid–liquid microextraction for metals enrichment: A useful strategy for improving sensitivity of laser-induced breakdown spectroscopy in liquid samples analysis

A rapid and efficient Dispersive Liquid–Liquid Microextraction (DLLME) followed by Laser-Induced Breakdown Spectroscopy detection (LIBS) was evaluated for simultaneous determination of Cr, Cu, Mn, Ni and Zn in water samples. Metals in the samples were extracted with tetrachloromethane as pyrrolidinedithiocarbamate (APDC) complexes, using vortex agitation to achieve dispersion of the extractant solvent. Several DLLME experimental factors affecting extraction efficiency were optimized with a multivariate approach. Under optimum DLLME conditions, DLLME-LIBS method was found to be of about 4.0–5.5 times more sensitive than LIBS, achieving limits of detection of about 3.7–5.6 times lower. To assess accuracy of the proposed DLLME-LIBS procedure, a certified reference material of estuarine water was analyzed.The authors are grateful to the Spanish Government (project no. CTQ2011-23968) and Regional Government of Valencia (Spain) (project no. ACOMP/2013/072) for the financial support

A Finite State and Data-Oriented Method for Grapheme to Phoneme Conversion

A finite-state method, based on leftmost longest-match replacement, is presented for segmenting words into graphemes, and for converting graphemes into phonemes. A small set of hand-crafted conversion rules for Dutch achieves a phoneme accuracy of over 93%. The accuracy of the system is further improved by using transformation-based learning. The phoneme accuracy of the best system (using a large set of rule templates and a `lazy' variant of Brill's algoritm), trained on only 40K words, reaches 99% accuracy.Comment: 8 page

Selectivity enhancement in capillary electrophoresis – development of a two-dimensional separation and a dual detection system

For the analysis of complex samples such as biological or environmental ones, highly selective analytical strategies are required. The selectivity can be enhanced by means of hyphenation of orthogonal separation techniques or combination of complementary detectors as an alternative concept. In this work, an example for both concepts is presented, respectively. First, methodical and instrumental studies concerning the comprehensive hyphenation of the two most important instrumental techniques in ion analysis namely ion chromatography (IC) and capillary electrophoresis (CE) are described enabling the simultaneous determination of anions and cations. Further, the combination of capacitively coupled conductless conductivity detection (C4D) and mass spectrometry (MS) as dual detection concept for CE is introduced and applied using aqueous and non-aqueous background electrolyte systems. Another concept to enhance the selectivity is rendering the separation technique compatible to a highly selective detector such as MS. Thus, in a third part, an approach is presented enabling the coupling of surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC) to MS. For the comprehensive hyphenation of capillary IC and CE, a modulator was developed ensuring well-controlled injections from the first to the second dimension. This was achieved by periodical injection of the IC effluent from a transfer capillary to the CE separation capillary by capillary batch injection. Important for the coupling was the compatibility of the two systems. Thus, the characteristics of the advanced capillary high performance IC with flow rates in the lower µL/min range facilitated the hyphenation being closer to CE conditions compared to IC with conventional columns. Due to the implemented capillary scale suppressor technology, the IC effluent consisted of analyte and pure water avoiding matrix concerned interferences and enabling exploitation of analyte stacking in CE. Further, fast CE measurements in the time range of seconds enabled the comprehensive coupling. Proof-of-concept measurements were performed using a model system containing nucleotides and their cyclic derivates. It was shown that the separation performance could be enhanced in the two-dimensional ICxCE-MS system compared to the single techniques. The work was further expanded to a methodical study concerning the simultaneous determination of positively and negatively charged analytes. A bypass system for IC was developed using a switching valve. This configuration enabled the cations bypassing the suppressor and thus they were not filtered out by the cation exchange membrane of the suppressor being not selective to eluent cations. Feasibility of the setup was demonstrated separating a model mixture of different arsenic species. The cations were eluted with water from the anion exchange column before driving a KOH gradient elution for the separation of anions. The injection parameters of the modulator introducing the IC effluent into the CE-MS system were studied taking into account the complex transport situation. It was found that the migration times were stable even for highly frequent injections with waiting times between the injections that were a factor four shorter than the migration time itself. Signal intensity of the MS was highest for positively charged species caused by the discriminating effect of the electrokinetic injection and the better ionization of the organic arsenic species by the electrospray ionization (ESI) source. Further, the coupling of two important detectors for CE is presented, namely capacitively coupled contactless conductivity detection (C4D) and electrospray ionization time-of-flight MS (ESI-TOF-MS). An experimental protocol was developed taking into account the requirements of the separation aspects and the compatibility with both detectors. ESI-TOF-MS requires background electrolytes consisting of volatile components such as ammonium acetate or formate. These, however, exhibit a rather high conductivity, which is disadvantageous for C4D. A 10 mM ammonium acetate/ammonia buffer was taken as compromise concerning the detection performance of both detectors. A sample containing various phenolic compounds serving as a model system was determined. The analytical characteristics showed the complementarity and suitability of this dual detection approach as C4D showed better response behavior towards m-cresol (limit of detection (LOD)=3.1 µM), while MS was more sensitive for determinations of m- and p-nitrophenol (LODs=0.8 µM) and 2,4-dinitrophenol (LOD=1.5 µM). The overall separation efficiency was excellent realizing the separation of counter-electroosmotic species with migration times of less than 60 s and illustrating that detector-induced band broadening could be neglected in the CE-C4D/MS system. In a second study, non-aqueous electrolytes were used for CE separations as they are highly compatible with both detectors due to their volatility and low background conductivity. A non-aqueous capillary electrophoresis (NACE)-C4D-MS method was developed using an acetonitrile based background electrolyte containing 2 M HAc and 4 mM NH4Ac enabling fast electrophoretic separations. Concentration changes of the background electrolyte and the choice of the inner diameter (ID) of the separation capillary were more critical for C4D than for MS. To choose a separation capillary with appropriate ID, the dependency of the sensitivity of the C4D on the ID was studied resulting in the use of a capillary with ID of 50 µm. The complementarity of the two detectors was demonstrated determining inorganic anions such as chloride, bromide, and nitrate (C4D) as well as organic biomolecules such as choline, thiamine, and acetylcholine (MS) simultaneously. A calibration was performed and the method applied on an extract of a food supplement quantifying the model analytes using the respective detector. MEEKC is a powerful tool for the separation of neutral species based on differences in their hydrophobic and hydrophilic properties. However, conventionally used SDS-based microemulsions are not compatible with ESI-MS. Enhancing the selectivity of the overall method, a surfactant-free microemulsion (SFME) based on water, ethanol, and 1-octanol was used as background electrolyte ensuring compatibility with ESI-TOF-MS. The small-angle X-ray scattering and dynamic light scattering measurements proved that the addition of ammonium acetate, which was necessary for the electrophoretic separation, was not altering aggregate formation in the SFME in the chosen concentration range. The separation performance of SF-MEEKC was demonstrated separating a model system consisting of hydrophobic and hydrophilic neutral vitamins, namely the vitamins B2 and D3, and the cationic vitamin B1 using UV/VIS detection. The influence of the ammonium acetate concentration on the separation performance was studied in detail. Characterization of the developed method was performed concerning reproducibility of migration times and peak areas and concerning the linearity of the calibration data. Further, the compatibility of SF-MEEKC with ESI-MS was shown determining the content of vitamin D3 in a commercial drug. Comparable sensitivity to aqueous CE-ESI-MS was achieved

How reliable are systematic reviews in empirical software engineering?

BACKGROUND – the systematic review is becoming a more commonly employed research instrument in empirical software engineering. Before undue reliance is placed on the outcomes of such reviews it would seem useful to consider the robustness of the approach in this particular research context. OBJECTIVE – the aim of this study is to assess the reliability of systematic reviews as a research instrument. In particular we wish to investigate the consistency of process and the stability of outcomes. METHOD – we compare the results of two independent reviews under taken with a common research question. RESULTS – the two reviews find similar answers to the research question, although the means of arriving at those answers vary. CONCLUSIONS – in addressing a well-bounded research question, groups of researchers with similar domain experience can arrive at the same review outcomes, even though they may do so in different ways. This provides evidence that, in this context at least, the systematic review is a robust research method

Hyphenation of single-drop microextraction with laser-induced breakdown spectrometry for trace analysis in liquid samples: a viability study

In this work, an analytical methodology based on single drop microextraction (SDME) followed by Laser-Induced Breakdown Spectrometry (LIBS) has been tested for trace metal determination in liquid samples. By this method, analytes in the samples were extracted into a small volume of toluene as ammonium pyrrolidinedithiocarbamate (APDC) chelates. After that, the analyte-enriched toluene was dried on a solid substrate and, finally, the resulting solid residue was analyzed by LIBS. Analyte extraction by the SDME procedure was optimized for the first time by using a multivariate optimization approach. Under optimum SDME conditions, analytical figures of merit of the proposed SDME-LIBS methodology were compared to those of the direct LIBS analysis method (i.e., without the SDME procedure). An estuarine water certified reference material was analyzed for method trueness evaluation. The results obtained in this study indicate that SDME-LIBS methodology leads to a sensitivity increase of about 2.0–2.6 times the ones obtained by LIBS. Detection limits of SDME-LIBS decrease according to the obtained sensitivity improvement, reaching values in the range 21–301 μg kg−1 for the analytes tested. The measurement repeatability was similar in both SDME-LIBS (13–20% RSD) and LIBS (16–20% RSD) methodologies, mainly limited by the LIBS experimental setup used in this work for LIBS analysis of liquid samples. The SDME-LIBS analysis of the certified reference material led to recovery values in the range of 96% to 112%.The authors are grateful to the Spanish Government (projects CTQ2011-23968) and the Regional Government of Valencia (Spain) (ACOMP/2013/072) for the financial support. M.A.A. is grateful to the University of Alicante for his PhD fellowship. This work is part of the PhD degree of M.A.A