Sampling dan analisis cemaran senyawa organoklorin dalam air laut Jawa

ABSTRAK Suatu penyelidikan telah dilakukan untuk mengetahul tingkat pecemaran air taut oleh senyawa organoklorin, yakni poliklorbifenil (PCB) dan turunan DDT. Pengambilan contoh air taut sebanyak 100 liter yang kemudian disaring untuk memisahkan bahan tersuspensi. Ektraksi polutan baik dart air saringan maupun dad bahan tersuspensi dilakukan dengan menggunakan heksana. Analisis kualitatif dan kuantitatif dilakukan dengan kromatografi gas memakal kolom kapiler dan dilengkapi dengan ECD, pengambilan contoh otomatik dan integrator. Suhu kolom &program dart 60°C sampai 180°C. Hasil menunjukkan bahwa p\u27,p\u27-DDE ditemukan dimuara Sungai Porong, dan cemaran PCB ditemukan dekat kota Surabaya. Kedua fens senyawa tersebut lebih banyak ditemukan di Selat Madura bagian barat. Di Laut Jawa sangat rendah (harga tertinggi hanya 0.15 Lg/g lemak). Hasil keseluruhan kadar turunan DDT dan PCB masih dibawah ambang batas toksisitas. Kata kunci: Air taut, polikiorbifenils, penyari lssabella. ABSTRACT Organochlorine compounds polichlorbiphenils (PCBs) and DDT derivative are very undegradable. The compounds are very toxic, and very unsoluble in water. Therefore was required a hundret liters of sea water to analize them. Sea water was filtered and taken by vacuum pump into a 100 litre of container. The sample was pressed through a fine porous filter for collecting the suspended matter and push it into an lssabetla extractor, using hexane as a solvent. Hexane was dried using evaporator and the solid risidue was collected. About 100 mg of residue was accurately weight and disoived into 10 ml hexana, applied into an alumina and then into an silica coloumn respectively to sparate fatty acid, D7T derivative and PCB. The sample was eluted using hexane and hexane-ethyl ether (9:1) sequently. The suspended matter was ektracted with hexane continuously using Soxhlet and than was separated by alumina and silica coloumn. The solution was concentrated and applied on Gas liquid Chromatographic apparatus using open capilary coloumn. Temperature of the coloumn was programed from 60° to 180° and steply incresed by 5°C per minute, using automatic sampler, ECO, and programable intregrator. The results showed that pCp. DDE was found in Porong river\u27s estuarian. PCB was found in the beach around of Surabaya. Both DDT derivative and PCB were much more found in western part of Madura Strait, while in Java Sea they were found in very low concentration (0.15 p.g/g fat matterial). It was obtained that DDT and PCBs were below the minimum toxical limit

High-resolution measurement of the time-modulated orbital electron capture and of the β+\beta^+ decay of hydrogen-like 142^{142}Pm60+^{60+} ions

The periodic time modulations, found recently in the two-body orbital electron-capture (EC) decay of both, hydrogen-like $^{140}$Pr$^{58+}$ and $^{142}$Pm$^{60+}$ ions, with periods near to 7s and amplitudes of about 20%, were re-investigated for the case of $^{142}$Pm$^{60+}$ by using a 245 MHz resonator cavity with a much improved sensitivity and time resolution. We observed that the exponential EC decay is modulated with a period $T = 7.11(11)$s, in accordance with a modulation period $T = 7.12(11)$ s as obtained from simultaneous observations with a capacitive pick-up, employed also in the previous experiments. The modulation amplitudes amount to $a_R = 0.107(24)$ and $a_P = 0.134(27)$ for the 245 MHz resonator and the capacitive pick-up, respectively. These new results corroborate for both detectors {\it exactly} our previous findings of modulation periods near to 7s, though with {\it distinctly smaller} amplitudes. Also the three-body $\beta^+$ decays have been analyzed. For a supposed modulation period near to 7s we found an amplitude $a = 0.027(27)$, compatible with $a = 0$ and in agreement with the preliminary result $a = 0.030(30)$ of our previous experiment. These observations could point at weak interaction as origin of the observed 7s-modulation of the EC decay. Furthermore, the data suggest that interference terms occur in the two-body EC decay, although the neutrinos are not directly observed.Comment: In memoriam of Prof. Paul Kienle, 9 pages, 1 table, 5 figures Phys. Lett. B (2013) onlin

Maintaining ecosystem resilience: functional responses of tree cavity nesters to logging in temperate forests of the Americas

Logging often reduces taxonomic diversity in forest communities, but little is known about how this biodiversity loss affects the resilience of ecosystem functions. We examined how partial logging and clearcutting of temperate forests influenced functional diversity of birds that nest in tree cavities. We used point-counts in a before-after-control-impact design to examine the effects of logging on the value, range, and density of functional traits in bird communities in Canada (21 species) and Chile (16 species). Clearcutting, but not partial logging, reduced diversity in both systems. The effect was much more pronounced in Chile, where logging operations removed critical nesting resources (large decaying trees), than in Canada, where decaying aspen Populus tremuloides were retained on site. In Chile, logging was accompanied by declines in species richness, functional richness (amount of functional niche occupied by species), community-weighted body mass (average mass, weighted by species densities), and functional divergence (degree of maximization of divergence in occupied functional niche). In Canada, clearcutting did not affect species richness but nevertheless reduced functional richness and community-weighted body mass. Although some cavity-nesting birds can persist under intensive logging operations, their ecosystem functions may be severely compromised unless future nest trees can be retained on logged sites.Fil: Ibarra, José Tomás. University of British Columbia; Canadá. Pontificia Universidad Católica de Chile; ChileFil: Martin, Michaela. University of British Columbia; CanadáFil: Cockle, Kristina Louise. University of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Martin, Kathy. University of British Columbia; Canad

Oscillatory Cortical Network Involved in Auditory Verbal Hallucinations in Schizophrenia

Auditory verbal hallucinations (AVH), a prominent symptom of schizophrenia, are often highly distressing for patients. Better understanding of the pathogenesis of hallucinations could increase therapeutic options. Magnetoencephalography (MEG) provides direct measures of neuronal activity and has an excellent temporal resolution, offering a unique opportunity to study AVH pathophysiology.Twelve patients (10 paranoid schizophrenia, 2 psychosis not otherwise specified) indicated the presence of AVH by button-press while lying in a MEG scanner. As a control condition, patients performed a self-paced button-press task. AVH-state and non-AVH state were contrasted in a region-of-interest (ROI) approach. In addition, the two seconds before AVH onset were contrasted with the two seconds after AVH onset to elucidate a possible triggering mechanism.AVH correlated with a decrease in beta-band power in the left temporal cortex. A decrease in alpha-band power was observed in the right inferior frontal gyrus. AVH onset was related to a decrease in theta-band power in the right hippocampus.These results suggest that AVH are triggered by a short aberration in the theta band in a memory-related structure, followed by activity in language areas accompanying the experience of AVH itself

Meta-analysis and the science of research synthesis

Meta-analysis is the quantitative, scientific synthesis of research results. Since the term and modern approaches to research synthesis were first introduced in the 1970s, meta-analysis has had a revolutionary effect in many scientific fields, helping to establish evidence-based practice and to resolve seemingly contradictory research outcomes. At the same time, its implementation has engendered criticism and controversy, in some cases general and others specific to particular disciplines. Here we take the opportunity provided by the recent fortieth anniversary of meta-analysis to reflect on the accomplishments, limitations, recent advances and directions for future developments in the field of research synthesis

Electrical Brain Responses to an Auditory Illusion and the Impact of Musical Expertise

The presentation of two sinusoidal tones, one to each ear, with a slight frequency mismatch yields an auditory illusion of a beating frequency equal to the frequency difference between the two tones; this is known as binaural beat (BB). The effect of brief BB stimulation on scalp EEG is not conclusively demonstrated. Further, no studies have examined the impact of musical training associated with BB stimulation, yet musicians' brains are often associated with enhanced auditory processing. In this study, we analysed EEG brain responses from two groups, musicians and non-musicians, when stimulated by short presentation (1 min) of binaural beats with beat frequency varying from 1 Hz to 48 Hz. We focused our analysis on alpha and gamma band EEG signals, and they were analysed in terms of spectral power, and functional connectivity as measured by two phase synchrony based measures, phase locking value and phase lag index. Finally, these measures were used to characterize the degree of centrality, segregation and integration of the functional brain network. We found that beat frequencies belonging to alpha band produced the most significant steady-state responses across groups. Further, processing of low frequency (delta, theta, alpha) binaural beats had significant impact on cortical network patterns in the alpha band oscillations. Altogether these results provide a neurophysiological account of cortical responses to BB stimulation at varying frequencies, and demonstrate a modulation of cortico-cortical connectivity in musicians' brains, and further suggest a kind of neuronal entrainment of a linear and nonlinear relationship to the beating frequencies