Analytical methods for PCBs and organochlorine pesticides in environmental monitoring and surveillance: a critical appraisal

Analytical methods for the analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are widely available and are the result of a vast amount of environmental analytical method development and research on persistent organic pollutants (POPs) over the past 30–40 years. This review summarizes procedures and examines new approaches for extraction, isolation, identification and quantification of individual congeners/isomers of the PCBs and OCPs. Critical to the successful application of this methodology is the collection, preparation, and storage of samples, as well as specific quality control and reporting criteria, and therefore these are also discussed. With the signing of the Stockholm convention on POPs and the development of global monitoring programs, there is an increased need for laboratories in developing countries to determine PCBs and OCPs. Thus, while this review attempts to summarize the current best practices for analysis of PCBs and OCPs, a major focus is the need for low-cost methods that can be easily implemented in developing countries. A “performance based” process is described whereby individual laboratories can adapt methods best suited to their situations. Access to modern capillary gas chromatography (GC) equipment with either electron capture or low-resolution mass spectrometry (MS) detection to separate and quantify OCP/PCBs is essential. However, screening of samples, especially in areas of known use of OCPs or PCBs, could be accomplished with bioanalytical methods such as specific commercially available enzyme-linked immunoabsorbent assays and thus this topic is also reviewed. New analytical techniques such two-dimensional GC (2D-GC) and “fast GC” using GC–ECD may be well-suited for broader use in routine PCB/OCP analysis in the near future given their relatively low costs and ability to provide high-resolution separations of PCB/OCPs. Procedures with low environmental impact (SPME, microscale, low solvent use, etc.) are increasingly being used and may be particularly suited to developing countries. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00216-006-0765-y and is accessible for authorized users

Timesharing in relation to broad ability domains

[Abstract]: The concept of a timesharing ability has been the subject of considerable interest in recent times. The present study set out to determine whether a timesharing factor can be identi¬fied when a number of competing tasks are presented in the midst of a range of single tests designed to sample a broad range of psychological dimensions. Evidence for the existence of such a factor would form an important addition to our knowledge of human cognitive functioning. The framework for the study was provided by the theory of fluid and crystallized intelligence. A battery of single and competing tasks was presented to 126 subjects. The competing tasks represented a variety of within- and across-factor combinations from different levels of the (Gf/Gc) hierarchy. Modality of presentation was also varied in some combinations. On the basis of evidence presented in this study, it would be pre¬mature to seek to include a timesharing factor in the (Gf/Gc) model of intelligence

Supplement to: Air concentrations of polybrominated diphenyl ethers (PBDEs) in 2002-2004 at a rural site in the Great Lakes

Atmospheric PBDEs were measured on a monthly basis in 2002-2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg m**-3 for the sum of 14BDE (excluding BDE-209), and 1.8 ± 1.5 pg m**-3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge-Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west-northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period

Sagittal and vertical craniofacial growth and attainment of circumpubertal middle phalanx maturation (MPM) stages: A multiple regression study

Introduction: Orthodontic treatment for most of the skeletal malocclusions have specific optimal timing according to the skeletal maturation phases. The knowledge of whether attainment of a specific maturation phase is associated with the different sagittal and vertical craniofacial growth pattern then becomes of clinical relevance. Aim: This cross-sectional study evaluated whether sagittal and vertical craniofacial growth pattern, has an association with the age of attainment of the circumpubertal skeletal maturation phases. Materials and methods: A total of 300 subjects (170 females and 130 males) were included in the study (mean age, 12.0 ±1.5 years; range, 8.3-15.6 years). These subjects were equally distributed in the circumpubertal middle phalanx maturation (MPM) stages 2, 3 and 4. Subsequently,multiple regression models were run for each MPM stage group to assess the significance of the association of cephalometric parameters(SNA, SNB, ANB, PP/MP, CoGoMe, SN/MP and NSBa angles) with age of attainment of the corresponding MPM stage (in months). Results: Only sex yielded significant associations, with females having anticipated attainment of each of the circumpubertal MPM stage. Conclusion: These results show no significant correlations of the different sagittal and vertical cephalometric parameters with the age of attainment of the circumpubertal skeletal maturation phases

A Genetic Algorithm With Self-Generated Random Parameters

In this paper we present a version of genetic algorithm (GA) where parameters are created by the GA itself, rather than predetermined by the programmer. Chromosome portions which do not translate into fitness (“genetic residual”) are given function to diversify control parameters for the GA,providing random parameter setting along the way, and doing away with fine-tuning of probabilities of crossover and mutation. We test the algorithm on Royal Road functions to examine the difference between our version (GAR) and the simple genetic algorithm (SGA) in the speed of discovering schema and creating building blocks. We also look at the usefulness of other standard improvements, such as non-coding segments, elitist selection and multiple crossover on the evolution of schema

Transnational telepathology consultations using a basic digital microscope: experience in the Italy-Slovenjia INTERREG project “Patient without borders”

<p>Abstract</p> <p>Background</p> <p>In recent years, a number of technological advancements started to modify the long standing appearance and functionalities of traditional optical microscopes used in Pathology and other medical fields. In fact, at present many new tools for microscopical visualization exist that are based on digital imaging, robotization, and remote communication. Such tools are typically adopted in activities ranging from education to telediagnosis to remote consultation.</p> <p>Present paper describes the features of a basic digital microscope that has been tested to verify its performance for occasional remote consultation inside an international project between Italy and Slovenija, funded by Interreg initiative of the European Regional Development Fund.</p> <p>Methods</p> <p>The system is composed by a pair of digital microscopes (Leica DMD108, Leitz Microsystems, Wetzlar, Germany) associated to a high resolution videoconferencing systems (Tandberg 990, Lysaker, Norway). The systems are connected through the Internet. Sixty histology and cytology cases have been collaboratively diagnosed between two Pathology Institutes to verify the diagnostic performance of the system, regarding the image quality point of view as well as time needed for diagnosis. The system has also been tested for compatibility with standard videoconferencing software.</p> <p>Results</p> <p>No discrepancies between local and remote diagnoses have been identified, with diagnosis time reasonably close to typical microscope observation times. Time needed for most operations is not far from that needed on a traditional microscope, except for startup.</p> <p>Conclusions</p> <p>The system can be considered usable as a standard microscope, and also for occasional remote consultations.</p

Criterios de arquitectura bioclimática aplicados al diseño de una residencia universitaria en el distrito de Pimentel, Lambayeque, 2023

El planteamiento del problema de la presente investigación consiste en que las universidades en Chiclayo no cuentan con espacios adecuados para ser destinados de manera exclusiva como residencias de los migrantes universitarios, y los centros de hospedaje aledaños no cumplen los estándares establecidos, o se encuentran en pésimas condiciones. Es por ello que se ha formulado la siguiente problemática general: ¿Cómo diseñar una Diseñar una Residencia universitaria aplicando criterios de arquitectura bioclimática, que mejore las condiciones de los estudiantes, ubicada en el Distrito de Pimentel, Provincia de Chiclayo, Región Lambayeque? Como objetivo general se planteó: Diseñar una Residencia universitaria para estudiantes migrantes y de la región, aplicando principios de la arquitectura bioclimática, con la finalidad de mejorar sus condiciones actuales. La investigación tiene una metodología cualitativa, del tipo descriptiva, propositiva, basada en un diseño No experimental. Los resultados de la investigación permitieron identificar que la propuesta facilitará plantear no solo un modelo arquitectónico, sino también la incidencia que tendrá esta infraestructura en los aspectos medio ambientales, juntamente con la secuencia de valor que se le ha dado a cada una de las actividades que se llevarán a cabo en su construcción. Finalmente, se puede concluir que el desarrollo de la propuesta innovadora de residencia universitaria que responde a las necesidades de los estudiantes fomenta la interacción e integración cultural, se integra de manera armónica con el entorno y utiliza los conceptos de la arquitectura bioclimática para lograr un edificio sostenible y eficiente energéticamente

(1R,2R,5R,6R,9S,10S,13S,14S)-1,6,7,8,9,14,15,16,17,17-Decachloro­penta­cyclo­[12.2.1.16,9.02,13.05,10]octa­deca-7,15-diene

The title compound, C18H14Cl10, is a decachlorinated commercial flame retardant. The structure determination confirms the relative stereochemistry. The central eight-membered ring is in a chair-type conformation. In the crystal structure, there are no significant inter­molecular inter­actions and mol­ecules are separated by normal van der Waals distances

Polycyclic Aromatic Hydrocarbons not declining in Arctic air despite global emission reduction

Two decades of atmospheric measurements of polycyclic aromatic hydrocarbons (PAHs) were conducted at three Arctic sites, i.e., Alert, Canada; Zeppelin, Svalbard; and Pallas, Finland. PAH concentrations decrease with increasing latitude in the order of Pallas>Zeppelin>Alert. Forest fire was identified as an important contributing source. Three representative PAHs, phenanthrene (PHE), pyrene (PYR), and benzo(a)pyrene (BaP) were selected for the assessment of their long-term trends. Significant decline of these PAHs was not observed contradicting the expected decline due to PAH emission reductions. A global 3-D transport model was employed to simulate the concentrations of these three PAHs at the three sites. The model predicted that warming in the Arctic would cause the air concentrations of PHE and PYR to increase in the Arctic atmosphere, while that of BaP, which tends to be particle-bound, is less affected by temperature. The expected decline due to the reduction of global PAH emissions is offset by the increment of volatilization caused by warming. This work shows that this phenomenon may affect the environmental occurrence of other anthropogenic substances, such as, the more volatile flame retardants and pesticides