Marcatili's Lossless Tapers and Bends: an Apparent Paradox and its Solution

Numerical results based on an extended BPM algorithm indicate that, in Marcatili's lossless tapers and bends, through-flowing waves are drastically different from standing waves. The source of this surprising behavior is inherent in Maxwell's equations. Indeed, if the magnetic field is correctly derived from the electric one, and the Poynting vector is calculated, then the analytical results are reconciled with the numerical ones. Similar considerations are shown to apply to Gaussian beams in free space.Comment: 4 pages, figures include

The effect of marine protected areas of the biological environment. A case of study in southern Sardinia (Capo Carbonara (MPA)

The growing interest in environmental issues and the establishment of new protected areas on land and seaside correspond to the worldwide need to understand and preserve the natural development of the ecosystems. The establishment of protected areas is fairly new for the marine habitat. It is becoming increasingly clear that marine protected areas represent an effective biodiversity conservation tool. Nowadays, there is a widespread growing need to recognize ecosystem interactions and to improve the effectiveness of protected areas in order to understand biological interrelations and human impacts. It was the lack of high quality and rigorous monitoring data concerning the marine protected areas (and not the lack of effects, which are almost certain) to bring us to perform the environmental monitoring described in this thesis. In order to understand the biological interactions of a marine protected area in the Mediterranean sea, a study was carried out inside and around the Marine Protected Area of Capo Carbonara located off the southern Sardinia Island. Samplings were performed to identify and quantify the benthonic fish stock and the composition of benthos in rocky shores at different depths and in different times of sampling. The composition of fish assemblages was evaluated both by the non-destructive visual census with SCUBA technique and the destructive method of the trammel net fishing. Fish assemblages in shallow rocky habitats (4–8 m deep) have been assessed between September 2004 and July 2005. Overall the list of target species included 24 species from 8 families (Labridae, Moronidae, Mullidae, Sciaenidae, Scorpaenidae, Serranidae, Sparidae, Sphiraenidae). The fish assemblages observed inside the protected area and outside, in the unprotected fished area were statistically different during all the sampling periods. Larger amount of fish was found in the protected than in the fished area, and differences were observed in total fish density, abundance, biomass: most fish species targeted by fisheries had a greater density (e.g. Diplodus puntazzo, Diplodus sargus, Diplodus vulgaris, Epinephelus marginatus, Mullus surmuletus, Pagrus pagrus, Sciena umbra, Scorpaena porcus, Serranus scriba, Sphyraena Sphyraena and Synphodus tinca) and/or size (e.g. Dentex dentex, Diplodus puntazzo, Diplodus sargus) within the protected area than in the fished areas outside. In the internal protected areas the Shannon Weaver diversity index showed richer ichtiofauna than outside, near the boundaries. Cluster analysis and MDS plot showed a general progressive increased similarity between protected and unprotected sites from the early census to the end, validating the spillover effects from inside to outside areas. These results indicate that reserve effects (protection) from fishing may have the potential to influence fish assemblages of outside areas. The composition of benthos in hard substrate, was examined applying benthic biocoenosis census through photographic and SCUBA techniques. Three years of sampling displayed the usefulness of the used techniques in a low budget study. The Visual census outcomes for macro benthic biocoenosis assemblages (5-25 m deep), assessed from September 2004 to May 2006, revealed 325 species (4 Phyla of Thallophyta, 1 of Anthophyta and 10 Phyla of Invertebrata) in all the analyzed sites. The analysis of the community structure revealed high biodiversity. In each sampling an ecological index classification as “Moderate” was recorded, both in the whole sanctuary and nearby the boundaries. In particular, some sites within the sanctuary showed a “Good” quality in different times and at different depths. Moreover, ecological and environmental factors able to modify the benthic composition often risked to warp outputs e.g. the presence of an alien species, the Caulerpa racemosa. In particular the analysis of these green algae within the sites was necessary because of its influence on the environment and consequently on the statistical analysis outputs. It is relevant that the recorded temporal scale of events can be useful for further analysis in the studied area and/or in other Marine Protected Areas. The application of this protocol seems to be a functional tool to manage marine environments almost until a co-ordinated network between the Mediterranean Marine Protected Areas will be create

The effect of marine protected areas of the biological environment. A case of study in southern Sardinia (Capo Carbonara (MPA)

The growing interest in environmental issues and the establishment of new protected areas on land and seaside correspond to the worldwide need to understand and preserve the natural development of the ecosystems. The establishment of protected areas is fairly new for the marine habitat. It is becoming increasingly clear that marine protected areas represent an effective biodiversity conservation tool. Nowadays, there is a widespread growing need to recognize ecosystem interactions and to improve the effectiveness of protected areas in order to understand biological interrelations and human impacts. It was the lack of high quality and rigorous monitoring data concerning the marine protected areas (and not the lack of effects, which are almost certain) to bring us to perform the environmental monitoring described in this thesis. In order to understand the biological interactions of a marine protected area in the Mediterranean sea, a study was carried out inside and around the Marine Protected Area of Capo Carbonara located off the southern Sardinia Island. Samplings were performed to identify and quantify the benthonic fish stock and the composition of benthos in rocky shores at different depths and in different times of sampling. The composition of fish assemblages was evaluated both by the non-destructive visual census with SCUBA technique and the destructive method of the trammel net fishing. Fish assemblages in shallow rocky habitats (4–8 m deep) have been assessed between September 2004 and July 2005. Overall the list of target species included 24 species from 8 families (Labridae, Moronidae, Mullidae, Sciaenidae, Scorpaenidae, Serranidae, Sparidae, Sphiraenidae). The fish assemblages observed inside the protected area and outside, in the unprotected fished area were statistically different during all the sampling periods. Larger amount of fish was found in the protected than in the fished area, and differences were observed in total fish density, abundance, biomass: most fish species targeted by fisheries had a greater density (e.g. Diplodus puntazzo, Diplodus sargus, Diplodus vulgaris, Epinephelus marginatus, Mullus surmuletus, Pagrus pagrus, Sciena umbra, Scorpaena porcus, Serranus scriba, Sphyraena Sphyraena and Synphodus tinca) and/or size (e.g. Dentex dentex, Diplodus puntazzo, Diplodus sargus) within the protected area than in the fished areas outside. In the internal protected areas the Shannon Weaver diversity index showed richer ichtiofauna than outside, near the boundaries. Cluster analysis and MDS plot showed a general progressive increased similarity between protected and unprotected sites from the early census to the end, validating the spillover effects from inside to outside areas. These results indicate that reserve effects (protection) from fishing may have the potential to influence fish assemblages of outside areas. The composition of benthos in hard substrate, was examined applying benthic biocoenosis census through photographic and SCUBA techniques. Three years of sampling displayed the usefulness of the used techniques in a low budget study. The Visual census outcomes for macro benthic biocoenosis assemblages (5-25 m deep), assessed from September 2004 to May 2006, revealed 325 species (4 Phyla of Thallophyta, 1 of Anthophyta and 10 Phyla of Invertebrata) in all the analyzed sites. The analysis of the community structure revealed high biodiversity. In each sampling an ecological index classification as “Moderate” was recorded, both in the whole sanctuary and nearby the boundaries. In particular, some sites within the sanctuary showed a “Good” quality in different times and at different depths. Moreover, ecological and environmental factors able to modify the benthic composition often risked to warp outputs e.g. the presence of an alien species, the Caulerpa racemosa. In particular the analysis of these green algae within the sites was necessary because of its influence on the environment and consequently on the statistical analysis outputs. It is relevant that the recorded temporal scale of events can be useful for further analysis in the studied area and/or in other Marine Protected Areas. The application of this protocol seems to be a functional tool to manage marine environments almost until a co-ordinated network between the Mediterranean Marine Protected Areas will be create

Investigation of Genetic Variants Associated with Tryptophan Metabolite Levels via Serotonin and Kynurenine Pathways in Patients with Bipolar Disorder

The kynurenine pathway (KP) may play a role in the pathophysiology of bipolar disorder (BD). We conducted a genome-wide association study (GWAS) to identify genetic variants associated with the plasma levels of the metabolites of tryptophan (TRP) via the serotonin (5-HT) and kynurenine (KYN) pathways in 44 patients with BD and 45 healthy controls. We assessed whether variants that were differentially associated with metabolite levels based on the diagnostic status improved the prediction accuracy of BD using penalized regression approaches. We identified several genetic variants that were significantly associated with metabolites (5-HT, 5-hydroxytryptophan (5-HTP), TRP, and quinolinic acid (QA) or metabolite ratios (5-HTP/TRP and KYN/TRP) and for which the diagnostic status exerted a significant effect. The inclusion of genetic variants led to increased accuracy in the prediction of the BD diagnostic status. Specifically, we obtained an accuracy of 0.77 using Least Absolute Shrinkage and Selection Operator (LASSO) regression. The predictors retained as informative in this model included body mass index (BMI), the levels of TRP, QA, and 5-HT, the 5-HTP/TRP ratio, and genetic variants associated with the levels of QA (rs6827515, rs715692, rs425094, rs4645874, and rs77048355) and TRP (rs292212) or the 5-HTP/TRP ratio (rs7902231). In conclusion, our study identified statistically significant associations between metabolites of TRP via the 5-HT and KYN pathways and genetic variants at the genome-wide level. The discriminative performance of penalized regression models incorporating clinical, genetic, and metabolic predictors warrants a follow-up analysis of this panel of determinants

Melatonin MT1 receptors as a target for the psychopharmacology of bipolar disorder: a translational study

The treatment of bipolar disorder (BD) still remains a challenge. Melatonin (MLT), acting through its two receptors MT1 and MT2, plays a key role in regulating circadian rhythms which are dysfunctional in BD. Using a translational approach, we examined the implication and potential of MT1 receptors in the pathophysiology and psychopharmacology of BD. We employed a murine model of the manic phase of BD (Clock mutant (ClockΔ19) mice) to study the activation of MT1 receptors by UCM871, a selective partial agonist, in behavioral pharmacology tests and in-vivo electrophysiology. We then performed a high-resolution Nuclear Magnetic Resonance study on isolated membranes to characterize the molecular mechanism of interaction of UCM871. Finally, in a cohort of BD patients, we investigated the link between clinical measures of BD and genetic variants located in the MT1 receptor and CLOCK genes. We demonstrated that: 1) UCM871 can revert behavioral and electrophysiological abnormalities of ClockΔ19 mice; 2) UCM871 promotes the activation state of MT1 receptors; 3) there is a significant association between the number of severe manic episodes and MLT levels, depending on the genetic configuration of the MT1 rs2165666 variant. Overall, this work lends support to the potentiality of MT1 receptors as target for the treatment of BD

A geostatistical approach for the stock assessment of the edible sea urchin, Paracentrotus lividus, in four coastal zones of Southern and West Sardinia (SW Italy, Mediterranean Sea)

Quantitative surveys of the edible sea urchin, Paracentrotus lividus, were conducted in four fishing zones of Sardinia (Southern Italy, Mediterranean Sea), in Autumn 2007. A total of 120 stations were geo-located along a bathymetric gradient ranging from 0 to 10 m. A geostatistical method was used to evaluate spatial patterns in density and to estimate harvestable stocks. Variographic analyses showed that the isotropic Gaussian and spherical models successfully explained the spatial structure of sea urchin assemblages in these areas. Density maps obtained by punctual kriging showed that sea urchin populations tend to be patchy rather than uniform in their density distribution. A combination of mapping and size categories was used to generate diverse scenarios of harvestable stocks (specimens ≥50 mm in diameter) before the start of the current fishing season. We conclude that the geostatistical approach, which takes into consideration the spatial autocorrelation structure of the populations in small areas, seems to be a good estimator of P. lividus density and biomass and for the assessment of its harvestable stocks, and thus provides an initial step towards a scientific approach to the management of local sea urchin fisherie

Confined growth of iron cobalt nanocrystals in mesoporous silica thin films: FeCo–SiO2 nanocomposites

Mesoporous silica films with controlled porosity were utilized as the host matrices to prepare FeCo–SiO2 nanocomposites through an impregnation process. The mesoporous silica films were first impregnated with a solution containing Co(II) and Fe(III) ions and then submitted to a reduction treatment under H2 flow. FeCo nanocrystals growth took place inside the mesopores, and their monodisperse size was dictated only by the size of the mesopores. We illustrate this process by the use of two different silica film matrices having different pore size and mesophase symmetry as the templates for the growth of FeCo alloy nanocrystals. The films and the nanocomposite samples were investigated by grazing-incidence small-angle X-ray scattering, X-ray diffraction and transmission electron microscopy. Unimpregnated mesoporous silica samples before and after the same thermal reduction treatment were also studied in order to investigate the mesopore structure variation upon the reduction treatment