Ion-selective electrodes: historical, mechanism of response, selectivity and concept review

This paper presents a review of the concepts involved in the working mechanism of the ion-selective electrodes, searching a historical overview, moreover to describe the new advances in the area.

L'efecte del canvi climàtic sobre els precursos de les aromes minoritàries del raïm

Aquest treball forma part d'un macroprojecte que pretén centrar-se en l'estudi de l'evolució dels precursos de les aromes minoritàries a la zona de la Rioja. Neix d'una inquietud que intenta esbrinar quins efectes globals té el canvi climàtic sobre les propietats químiques del raïm. Per tal de que es desenvolupi aquest projecte, prèviament es disposa d’un seguit de dades històriques i analítiques que permetran analitzar diferents paràmetres dels anys considerats com a anys d'estudi, que són 2009, 2010 i 2011. Els principals paràmetres que s'estudiaran són el GDD (Growing Degree Day) i la pluviometria, analitzant-los en tres collites diferents pels tres anys d’estudi , primer per separat i després junts per veure el seu efecte. Posteriorment, es farà un estudi més acurat de les diferents famílies químiques que hi ha, quina és la seva evolució així com, quines són les propietats químiques dels seus precursors minoritaris.

Fluidos supercríticos em química analítica. I. Cromatografia com fluido supercrítico: conceitos termodinâmicos

Under the chromatographic point of view, the physico-chemical properties of a supercritical fluid are intermediate to those of the gases and liquids. Many times they approach the best features of each one, as for example, the solubilization power of liquids and low viscosity of gases. The thermodynamic definitions and main physico-chemical features of a supercritical fluid will be presented in this article. The use of supercritical fluids in analytical chemistry has been extremely modest in Brazil, even considering the enormous potential of their applications, and their use in several techniques, such as chromatography (SFC) and supercritical fluid extration (SFE). This article series is intended to discuss the historical evolution, instrumentation features and potential and limitations of the supercritical fluid use in analytical chemistry. A special focus will be centered on chromatography and extration techniques using supercritical fluids.

A comparative study of difficulties in accounting preparation and judgement in agriculture using fair value and historical cost accounting for biological assets valuation

This paper presents empirical research comparing the accounting difficulties that arise from the use of two valuation methods for biological assets, fair value (FV) and historical cost (HC) accounting, in the agricultural sector. It also compares how reliable each valuation method is in the decision-making process of agents within the sector. By conducting an experiment with students, farmers, and accountants operating in the agricultural sector, we find that they have more difficulties, make larger miscalculations and make poorer judgements with HC accounting than with FV accounting. In-depth interviews uncover flawed accounting practices in the agricultural sector in Spain in order to meet HC accounting requirements. Given the complexities of cost calculation for biological assets and the predominance of small family business units in advanced Western countries, the study concludes that accounting can be more easily applied in the agricultural sector under FV than HC accounting, and that HC conveys a less accurate grasp of the real situation of a farm.

Ecological fallacy in a time series context: evidence from the Spanish regional unemployment rates

The ecological fallacy (EF) is a common problem regional scientists have to deal with when using aggregated data in their analyses. Although there is a wide number of studies considering different aspects of this problem, little attention has been paid to the potential negative effects of the EF in a time series context. Using Spanish regional unemployment data, this paper shows that EF effects are not only observed at the cross-section level, but also in a time series framework. The empirical evidence obtained shows that analytical regional configurations are the least susceptible to time effects relative to both normative and random regional configurations, while normative configurations are an improvement over random ones.

The Emerging Human Rights Revolution: The Beginning of the Fifth Historical Process in the Consolidation of Human Rights

Emerging human rights are destined to modify, improve and transform a number of already traditional concepts so as to achieve greater guarantees and protection for the rights of individuals and collectivities. One of the big changes that will be brought about by the concept and conception of emerging human rights is that, following on from the processes of positivization, generalization, internationalization and specification, they represent the beginning of the fifth historical process in the consolidation of human rights, namely the process of interaction. A number of breakthroughs have already been achieved, such as the recognition of emerging biocultural rights in the recently adopted Nagoya Protocol on access to genetic resources and shared benefits.

Isotype distribution of anticardiolipin antibodies in systemic lupus erythematosus prospective analysis of a series of 100 patients

A prospective study of IgG and IgM isotypes of anticardiolipin antibodies (aCL) in a series of 100 patients with systemic lupus erythematosus was carried out. To determine the normal range of both isotype titres a group of 100 normal control serum samples was studied and a log-normal distribution of IgG and IgM isotypes was found. The IgG anticardiolipin antibody serum was regarded as positive if a binding index greater than 2.85 (SD 3.77) was detected and a binding index greater than 4.07 (3.90) was defined as positive for IgM anticardiolipin antibody. Twenty four patients were positive for IgG aCL, 20 for IgM aCL, and 36 for IgG or IgM aCL, or both. IgG aCL were found to have a significant association with thrombosis and thrombocytopenia, and IgM aCL with haemolytic anaemia and neutropenia. Specificity and predictive value for these clinical manifestations increased at moderate and high anticardiolipin antibody titres. In addition, a significant association was found between aCL and the presence of lupus anticoagulant. Identification of these differences in the anticardiolipin antibody isotype associations may improve the clinical usefulness of these tests, and this study confirms the good specificity and predictive value of the anticardiolipin antibody titre for these clinical manifestations.

Analysis of patterns in mining time series using Qlucore

Raw measurement data does not always immediately convey useful information, but applying mathematical statistical analysis tools into measurement data can improve the situation. Data analysis can offer benefits like acquiring meaningful insight from the dataset, basing critical decisions on the findings, and ruling out human bias through proper statistical treatment. In this thesis we analyze data from an industrial mineral processing plant with the aim of studying the possibility of forecasting the quality of the final product, given by one variable, with a model based on the other variables. For the study mathematical tools like Qlucore Omics Explorer (QOE) and Sparse Bayesian regression (SB) are used. Later on, linear regression is used to build a model based on a subset of variables that seem to have most significant weights in the SB model. The results obtained from QOE show that the variable representing the desired final product does not correlate with other variables. For SB and linear regression, the results show that both SB and linear regression models built on 1-day averaged data seriously underestimate the variance of true data, whereas the two models built on 1-month averaged data are reliable and able to explain a larger proportion of variability in the available data, making them suitable for prediction purposes. However, it is concluded that no single model can fit well the whole available dataset and therefore, it is proposed for future work to make piecewise non linear regression models if the same available dataset is used, or the plant to provide another dataset that should be collected in a more systematic fashion than the present data for further analysis.

MCMC Analysis Of Classical Time Series Algorithms

Identification of order of an Autoregressive Moving Average Model (ARMA) by the usual graphical method is subjective. Hence, there is a need of developing a technique to identify the order without employing the graphical investigation of series autocorrelations. To avoid subjectivity, this thesis focuses on determining the order of the Autoregressive Moving Average Model using Reversible Jump Markov Chain Monte Carlo (RJMCMC). The RJMCMC selects the model from a set of the models suggested by better fitting, standard deviation errors and the frequency of accepted data. Together with deep analysis of the classical Box-Jenkins modeling methodology the integration with MCMC algorithms has been focused through parameter estimation and model fitting of ARMA models. This helps to verify how well the MCMC algorithms can treat the ARMA models, by comparing the results with graphical method. It has been seen that the MCMC produced better results than the classical time series approach.

Time-series forecasting of pollutant concentration levels using particle swarm optimization and artificial neural networks

This study evaluates the application of an intelligent hybrid system for time-series forecasting of atmospheric pollutant concentration levels. The proposed method consists of an artificial neural network combined with a particle swarm optimization algorithm. The method not only searches relevant time lags for the correct characterization of the time series, but also determines the best neural network architecture. An experimental analysis is performed using four real time series and the results are shown in terms of six performance measures. The experimental results demonstrate that the proposed methodology achieves a fair prediction of the presented pollutant time series by using compact networks.

SYNTHESIS AND BIOLOGICAL ACTIVITY OF NEW SERIES OF ORGANOTIN(IV) ESTERS WITH N,N-DIACETYLGLYCINE

A bioactive N,N-diacetylglycine (NNDAG) and new organotin(IV) complexes (OTCs) (1-7) were synthesized. Spectroscopic techniques were employed to characterize NNDAG and OTCs. FTIR was employed to verify N,N protection of glycine by acetyl groups. The disappearance of υ(OH) at 3000-2600 cm-1 showed de-protonation of free ligand. The Δυ 150<200 cm-1 of OTCs 4-7 verified bidentate coordination with tetrahedral geometry. The Δυ of OTCs1 and 3 was <200 cm-1 exhibitingtrans -octahedral geometry while OTC 2 dimer was assigned a unique sinusoidal view. The 1H NMR spectra of OTCs verified their synthesis by de-protonation of NNDAG and no chemical shift was found downfield for carboxylic acid proton. The 13C, 119Sn NMR and Mass spectrometric data also supported FTIR and 1H NMR descriptions. The OTCs 4, 5, 6 and7 (500 ppm) proved twice as active against Escherichia coli as the standard antibiotic enoxacin (1000 ppm). The promising property of the OTCs (4, 5, 6 and7) is clearly due to their tetrahedral. The OTCs 4and 5 exhibited excellent activity against M. minimum and good activity against T. castaneum.LD50 of all the compounds were determined and OTCs4, 5 and 7 were found to be active.

Regime Switching Models for Electricity Time Series that Capture Fat Tailed Distributions

In the power market, electricity prices play an important role at the economic level. The behavior of a price trend usually known as a structural break may change over time in terms of its mean value, its volatility, or it may change for a period of time before reverting back to its original behavior or switching to another style of behavior, and the latter is typically termed a regime shift or regime switch. Our task in this thesis is to develop an electricity price time series model that captures fat tailed distributions which can explain this behavior and analyze it for better understanding. For NordPool data used, the obtained Markov Regime-Switching model operates on two regimes: regular and non-regular. Three criteria have been considered price difference criterion, capacity/flow difference criterion and spikes in Finland criterion. The suitability of GARCH modeling to simulate multi-regime modeling is also studied.

Analysis of Patterns in Electricity Spot Market Time Series

Due to its non-storability, electricity must be produced at the same time that it is consumed, as a result prices are determined on an hourly basis and thus analysis becomes more challenging. Moreover, the seasonal fluctuations in demand and supply lead to a seasonal behavior of electricity spot prices. The purpose of this thesis is to seek and remove all causal effects from electricity spot prices and remain with pure prices for modeling purposes. To achieve this we use Qlucore Omics Explorer (QOE) for the visualization and the exploration of the data set and Time Series Decomposition method to estimate and extract the deterministic components from the series. To obtain the target series we use regression based on the background variables (water reservoir and temperature). The result obtained is three price series (for Sweden, Norway and System prices) with no apparent pattern.

Thermal decomposition and stability in a series of heterobimetallic carbonyl compounds of the type [Fe(CO)4(HgX)2] (X=Cl, Br, I)

Heterobimetallic carbonyl compounds of the type [Fe(CO)4(HgX)2] (X= Cl, Br, I), which have metal-metal bonds, have been prepared in order to study their thermal stabilities as a function of the halogen coordinated to mercury atoms. The characterization of the above complexes was carried out by elemental analysis, IR and NMR spectroscopies. Their thermal behaviour has been investigated and the final product was identified by IR spectroscopy and by X-ray powder diffractogram.

A fluorescence probe study of gemini surfactants in aqueous solution: a comparison between n-2-n and n-6-n series of the alkanediyl-a,w-bis (dimethylalkylammonium bromides)

Two series of alkanediyl-a,w-bis (dimethylalkylammonium bromide (n-2-n and n-6-n; n=8, 10,12, and 16) have been synthesized and their micelles properties studied in aqueous solution using pyrene, pyrenecarboxaldehyde (PCA) and 1,8 anilinonaphtalene sulfonic acid sodium salt (ANS) as fluorescent probes. The micelles from these surfactants have been characterized on the basis of the information provided by micelle-solubilized fluorescent probes. The obtained results indicated that the surfactant concentration at which a marked decrease in l max parameter of pyrenecarboxaldehyde (PCA) occurs corresponds to the CMC determined by conductimetric measurements. Changes in the emission spectra of ANS and PCA observed in the submicellar range for both surfactants series (n-2-n and n-6-n) were interpreted as formation of pre-aggregates. It was found that the dimeric surfactants with long spacer (s= 6) form more hydrated aggregates when compared with those formed by the n-2-n and CnTAB surfactants series. This was attributed to a more difficult packing of n-6-n surfactant molecules to form micelles.