10 research outputs found
I tratti distintivi degli operatori del terzo settore: un percorso di ricerca sul campo per la determinazione delle professionalità esistenti e delle competenze richieste dal mondo del lavoro
Il lavoro presenta i risultati della ricerca realizzatat per la definizione delle professionalità esistenti ed emergenti nel terzo settore, con particolare riferimento all’ambito dei servizi agli immigrati
Bacterial Community Dynamics and Hydrocarbon Degradation during a Field-Scale Evaluation of Bioremediation on a Mudflat Beach Contaminated with Buried Oil
A field-scale experiment with a complete randomized block design was performed to study the degradation of buried oil on a shoreline over a period of almost 1 year. The following four treatments were examined in three replicate blocks: two levels of fertilizer treatment of oil-treated plots, one receiving a weekly application of liquid fertilizer and the other treated with a slow-release fertilizer; and two controls, one not treated with oil and the other treated with oil but not with fertilizer. Oil degradation was monitored by measuring carbon dioxide evolution and by chemical analysis of the oil. Buried oil was degraded to a significantly greater extent in fertilized plots, but no differences in oil chemistry were observed between the two different fertilizer treatments, although carbon dioxide production was significantly higher in the oil-treated plots that were treated with slow-release fertilizer during the first 14 days of the experiment. Bacterial communities present in the beach sediments were profiled by denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA gene fragments and 16S rRNA amplified by reverse transcriptase PCR. Similarities between the DGGE profiles were calculated, and similarity matrices were subjected to statistical analysis. These analyses showed that although significant hydrocarbon degradation occurred both in plots treated with oil alone and in the plots treated with oil and liquid fertilizer, the bacterial community structure in these plots was, in general, not significantly different from that in the control plots that were not treated with oil and did not change over time. In contrast, the bacterial community structure in the plots treated with oil and slow-release fertilizer changed rapidly, and there were significant differences over time, as well as between blocks and even within plots. The differences were probably related to the higher concentrations of nutrients measured in interstitial water from the plots treated with slow-release fertilizer. Bacteria with 16S rRNA sequences closely related (>99.7% identity) to Alcanivorax borkumensis and Pseudomonas stutzeri sequences dominated during the initial phase of oil degradation in the plots treated with slow-release fertilizer. Field data were compared to the results of previous laboratory microcosm experiments, which revealed significant differences
Nontidal ocean loading: amplitudes and potential effects in GPS height time series
Ocean bottom pressure (OBP) changes are caused
by a redistribution of the ocean’s internal mass that are driven
by atmospheric circulation, a change in the mass entering or
leaving the ocean, and/or a change in the integrated atmospheric
mass over the ocean areas. The only previous global
analysis investigating the magnitude of OBP surface displacements
used older OBP data sets (van Dam et al. in
J Geophys Res 129:507–517, 1997). Since then significant
improvements in meteorological forcing models used to predict
OBP have been made, augmented by observations from
satellite altimetry and expendable bathythermograph profiles.
Using more recent OBP estimates from the Estimating
the Circulation and Climate of the Ocean (ECCO) project,
we reassess the amplitude of the predicted effect of OBP on
the height coordinate time series from a global distribution
of GPS stations. OBP-predicted loading effects display an
RMS scatter in the height of between 0.2 and 3.7 mm, larger
than previously reported but still much smaller (by a factor
of 2) than the scatter observed due to atmospheric pressure
loading. Given the improvement in GPS hardware and data
analysis techniques, the OBP signal is similar to the precision
of weekly GPS height coordinates. We estimate the effect of OBP on GPS height coordinate time series using
the MIT reprocessed solution, mi1. When we compare the
predicted OBP height time series with mi1, we find that the
scatter is reduced over all stations by 0.1 mm on average
with reductions as high as 0.7 mm at some stations. More
importantly we are able to reduce the scatter on 65 % of
the stations investigated. The annual component of the OBP
signal is responsible for 80 % of the reduction in scatter on
average.We find that stations located close to semi-enclosed
bays or seas are affected by OBP loading to a greater extent
than other stations