Microtesla NMR J-coupling spectroscopy with an unshielded atomic magnetometer

We present experimental data and theoretical interpretation of NMR spectra of remotely magnetized samples, detected in an unshielded environment by means of a differential atomic magnetometer. The measurements are performed in an ultra-low-field at an intermediate regime, where the J-coupling and the Zeeman energies have comparable values and produce rather complex line sets, which are satisfactorily interpreted.Comment: 8 pages, 8 figs, appearing in JMR (2016

Microplastics in the environment: risk of metallic pollution and social perspective

[Resumen]: El presente trabajo se centra en el estudio de la problemática derivada de los plásticos y los microplásticos a nivel ambiental y en la salud humana. Se estructura en dos partes. En la primera se aborda la temática desde una perspectiva social para evaluar el grado de interés y conocimiento de los ciudadanos sobre esta problemática. Para ello se evalúa el volumen de información divulgada en la prensa local de mayor difusión y se elabora una encuesta en línea dirigida a dos grupos de población. Se comprueba que a pesar de que la información difundida sobre la problemática de los plásticos es muy elevada, no lo es la relativa a los microplásticos y los encuestados manifiestan no estar bien informados. Por lo que se considera de interés un vídeo divulgativo que se incorporó al final de la encuesta. En general, los encuestados tienen una buena actitud hacia el uso sostenible de los materiales plásticos. En la segunda parte, se evalúa el grado de incorporación a nuestro organismo de metales que estén presentes en los microplásticos, realizando ensayos de biodisponibilidad oral de Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb y Sn en microplásticos (PET virgen), que previamente se han sometido a un proceso de adsorción metálica. Se comprueba que aproximadamente el 20% del Cu y el 50% de la concentración de Cr, Fe, Mn, Pb y Sb liberados desde el microplástico son biodisponibles. También se constató que el contenido metálico desorbido desde el microplástico puede proceder tanto de la propia matriz polimérica del PET (del 40% al 80% para el Cu, Fe, Mn y Sb) como de la fracción metálica adsorbida durante la exposición del microplástico a los contaminantes metálicos en el medio marino (hasta el 100% para el Cr y Pb).[Resumo]: O presente traballo céntrase no estudo da problemática derivada dos plásticos e os microplásticos a nivel ambiental e na saúde humana. Estructúrase en dúas partes. Na primeira abórdase a temática desde unha perspectiva social para avaliar o grao de interese e coñecemento dos individuos sobre esta problemática. Para isto, evalúase o volume de información divulgada na prensa local de maior difusión e elabórase unha enquisa en liña dirixida a dous grupos de poboación. Compróbase que malia a información difundida sobre a problemática dos plásticos é moi elevada, non o é a relativa ós microplásticos e os enquisados mostran non estar ben informados. Considérase de interese un vídeo divulgativo que se incorporou ó final da enquisa. En xeral, os enquisados mostran unha boa actitude de cara ó uso sostible dos materiais plásticos. Na segunda parte, avalíase o grao de incorporación ó noso organismo de metais presentes en microplásticos, realizando ensaios de biodispoñibilidade oral de Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb e Sn en microplásticos (PET virxe), que previamente sometéronse a un proceso de adsorción metálica. Compróbase que aproximadamente entre o 20% do Cu e o 50% da concentración de Cr, Fe, Mn, Pb e Sb liberados desde o microplástico son biodispoñibles. Tamén se notou que o contido metálico desorbido desde o microplástico pode proceder tanto da propia matriz polimérica do PET (do 40% ó 80% para o Cu, Fe, Mn e Sb) como da fracción metálica desorbida durante a exposición do microplástico ós contaminantes metálicos no medio mariño (ata o 100% para o Cr e Pb).[Abstract]: The present report deals with the study of the difficulties derived from plastic and microplastics at environmental and human levels. It is structured in two parts. In the first part, a evaluation of the degree of knowledge and concern of citizens about this problem is done from a social perspective. To achieve this, the amount of information given by the local press is assessed and an online survey among two population grupos was performed. It is found that despite the fact that the information given on the environmental problem of plastic is considerably high, there is not as much related to microplastics, so survey respondents answered do not seem to be informed on the subject. For this reason, an informative video was included at the end of the survey. In general, survey respondents had a good attitude towards the sustainable use of plastic materials. In the second part, the degree of inclusion of metals present in microplastics into our organism is assessed by performing oral bioavailability essays of Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb and Sn in microplastics (virgin PET), which have previously undergone a metal adsorption process. It is confirm that approximately 20 % of the Cu and 50 % of the Cr, Fe, Mn, Pb and Sb concentration released from the microplastic are bioavailable. It was also found that metal content desorbed from the microplastic can came from both PET polymeric matrix itself (from 40 % to 80 % for Cu, Fe, Mn and Sb) and from the metal fraction adsorbed during the exposure of the microplastic to metal pollutants in the marine environment (up to 100 % for Cr and Pb).Traballo fin de grao (UDC.CIE). Química. Curso 2020/202

Observation of the Inverse Cotton-Mouton Effect

We report the observation of the Inverse Cotton-Mouton Effect (ICME) i.e. a magnetization induced in a medium by non resonant linearly polarized light propagating in the presence of a transverse magnetic field. We present a detailed study of the ICME in a TGG crystal showing the dependence of the measured effect on the light intensity, the optical polarization, and on the external magnetic field. We derive a relation between the Cotton-Mouton and Inverse Cotton-Mouton effects that is roughly in agreement with existing experimental data. Our results open the way to applications of the ICME in optical devices

The Public Pension System in Romania – Analysis Before and After 1999

Objectives This paper aims to examine the public pension system in Romania and the significant differences that 1999 brought it. It is important to see if system effects such as the number of beneficiaries and collapse on the number of taxpayers are experienced in present. It explores the main types of pension granted in the public pension system - pensions for old age. Approach It is an attempt to identify the main sources (contributions owed by employers and employees) and also the way pensions are calculated and given before and after 1999. Results We conclude that public pension system in Romania has suffered many changes in a positive way. Implications For taxpayers, both employers and employees it is important that the public pension system work in optimal conditions, that the minimum and maximum contribution "stage" take the proper values. Value Knowing the importance of the public pension system in the Romanian society will know what measures should be taken to improve it

Massive structural and compositional changes over two decades in forest fragments near Kampala, Uganda

Private forests harbor considerable biodiversity, however, they are under greater threat than reserved areas, particularly from urbanization, agriculture, and intense exploitation for timber and fuel wood. The extent to which they may act as habitats for biodiversity and how level of protection impacts trends in biodiversity and forest structure over time remain underresearched. We contribute to filling this research gap by resampling a unique data set, a detailed survey from 1990 of 22 forests fragments of different ownership status and level of protection near Kampala, Uganda. Eleven of the 22 fragments were lost over 20 years, and six of the remnants reduced in size. Forest structure and composition also showed dramatic changes, with six of the remnant fragments showing high temporal species turnover. Species richness increased in four of the remaining forests over the resample period. Forest ownership affected the fate of the forests, with higher loss in privately owned forests. Our study demonstrates that ownership affects the fate of forest fragments, with private forests having both higher rates of area loss, and of structural and compositional change within the remaining fragments. Still, the private forests contribute to the total forest area, and they harbor biodiversity including IUCN “vulnerable” and “endangered” species. This indicates the conservation value of the fragments and suggests that they should be taken into account in forest conservation and restoration.publishedVersio

Crop raiding patterns of solitary and social groups of red-tailed monkeys on cocoa pods in Uganda

Crop damage by wildlife is a very prevalent form of human-wildlife conflict adjacent to protected areas, and great economic losses from crop raiding impede efforts to protect wildlife. Management plans are needed to decrease damage by raiding wildlife, yet conservation biologists typically lack the basic information needed for informed conservation strategies. Red-tailed monkeys (Cercopithecus ascanius) raid a variety of crops adjacent to protected forests in East Africa; however, the role of group structure on crop raiding has not been explored. Here, crop raiding patterns of solitary males and social groups were investigated during 10 months in a plantation of mature cocoa in Uganda. Monkeys gained access to the plantation via trees planted as wind breaks and shade trees, and the sighting frequency of groups was negatively related to the distance from the forest edge. In contrast, solitary males were sighted more frequently far from the forest edge and caused proportionately greater damage than members raiding in a social group. These results highlight that for social animals, crop raiding behavior can vary among types of social groupings; appropriate strategies to cope with raiding must therefore respond to this variation. Deborah Baranga, G. Isabirye Basuta, Julie A. Teichroeb, and Colin A. Chapman

Quantum Zeno effect in atomic spin-exchange collisions

The suppression of spin-exchange relaxation in dense alkali-metal vapors discovered in 1973 and governing modern atomic magnetometers is here reformulated in terms of quantum measurement theory and the quantum Zeno effect. This provides a new perspective of understanding decoherence in spin-polarized atomic vapors.Comment: 4 pages, 1 figur

The diet and feeding behavior of the black-and-white colobus (Colobus guereza) in the Kalinzu Forest, Uganda

One of the goals for primate feeding ecology is to understand the factors that affect inter- and intra-specific variations. Therefore, a detailed description of basic feeding ecology in as many populations as possible is necessary and warrants further understanding. The black-and-white colobus (Colobus guereza) or guereza is widely distributed in Africa and is one of the well-studied colobines in terms of their feeding; they demonstrate considerable variation in their diets in response to local conditions. We studied the diet of a group of guerezas in the Kalinzu Forest, Uganda, for over 30 consecutive months using behavioral observation (4308 h in total), phenology, and vegetation surveys. A total of 31 plant species were consumed by the study group. This study group was predominantly folivorous; the majority of their feeding time was involved in feeding on young leaves (87%). However, during certain times of the year, fruits and seeds accounted for 45% of monthly feeding time. Young leaves of Celtis durandii were by far the most important food, which constituted 58% of the total feeding records. There was a significant increase in the consumption of fruits and flowers once young leaf availability was low, but their consumption of fruits did not significantly increase even when fruit availability was high. Their monthly dietary diversity increased as the number of available plants with young leaves declined, suggesting that much of the dietary diversity in the study group may be attributable to the young leaf portion of their diet. Our findings may help contribute to a better understanding of the dietary adaptations and feeding ecology of guerezas in response to local environmental conditions