Caribbean Plate margin evolution : constraints and current problems

Oceanic crust was generated at multiple spreading centres during the Jurassic and Early Cretaceous, forming a "proto-Caribbean" oceanic domain. During the Cretaceous, part of that crustal domain thickened into an oceanic plateau, of petrologic Mid-Ocean Ridge (MOR) to Ocean Island Basalt (OIB) affinity. Simultaneously, the South and North American continental plates developed rifting and tholeiitic magmatism in the Middle America region (Venezuela and Cuba). The rifting created space for the proto-Caribbean oceanic domain. Petrological and regional correlations suggest that, beginning in the Cretaceous, the proto-Caribbean domain was involved into two main stages of subduction, referred to as first and second "eo-Caribbean" phases. Each phase is characterized by oblique convergence. The older (mid-Cretaceous) stage, involved in subduction (probably eastward dipping) of thin proto-Caribbean lithosphere, with generation of Island Arc Tholeiitic (IAT) and Calc-Alkaline (CA) magmatism, accompanied by high pressure - low temperature (HP - LT) metamorphic effects, and formation of arc units and ophiolitic melanges (Guatemala, Cuba, Hispaniola and Puerto Rico, in the northern margin; Venezuela in the southern). The Late Cretaceous second stage consisted of westward dipping intra-oceanic subduction; it is recorded by tonalitic arc magmatism related to the onset of the Aves - Lesser Antilles arc system. Since the Late Cretaceous, the inner undeformed portions of the Caribbean oceanic plateau (i.e. the Colombian and Venezuelan Basins) were trapped east of the Pacific subduction of the Chortis, Chorotega and Choco blocks, ultimately building the Central American Isthmus. From Tertiary to Present, continuous eastward movement of the Caribbean Plate with respect to the Americas, gave rise to transpression along both the northern and southern margins, marked by scattered and dismembered ophiolitic terranes

evolutionary frequency response function of linear systems subjected to earthquake accelerograms using the adaptive chirplet decomposition

Abstract In seismic engineering, in order to reproduce the typical characteristics of real earthquakes ground-motion time history, several approaches has been proposed in literature. In this study the adaptive chirplet signal decomposition is adopted to analyze recorded accelerograms in order of defining appropriately evolutionary power spectra [1]. The present study focuses on a method to evaluate in closed-form the evolutionary frequency response function, that is required to evaluate the statistics of the response of linear structural systems [2], once the adaptive chirplet signal decomposition is adopted

Caribbean Plate margin evolution: constraints and current problems

Oceanic crust was generated at multiple spreading centres during the Jurassic and Early Cretaceous, forming a “proto-Caribbean” oceanic domain. During the Cretaceous, part of that crustal domain thickened into an oceanic plateau, of petrologic Mid-Ocean Ridge (MOR) to Ocean Island Basalt (OIB) affinity. Simultaneously, the South and North American continental plates developed rifting and tholeiitic magmatism in the Middle America region (Venezuela and Cuba). The rifting created space for the proto-Caribbean oceanic domain. Petrological and regional correlations suggest that, beginning in the Cretaceous, the proto-Caribbean domain was involved into two main stages of subduction, referred to as first and second “eo-Caribbean” phases. Each phase is characterized by oblique convergence. The older (mid-Cretaceous) stage, involved in subduction (probably eastward dipping) of thin proto-Caribbean lithosphere, with generation of Island Arc Tholeiitic (IAT) and Calc-Alkaline (CA) magmatism, accompanied by high pressure - low temperature (HP - LT) metamorphic effects, and formation of arc units and ophiolitic melanges (Guatemala, Cuba, Hispaniola and Puerto Rico, in the northern margin; Venezuela in the southern). The Late Cretaceous second stage consisted of westward dipping intra-oceanic subduction; it is recorded by tonalitic arc magmatism related to the onset of the Aves - Lesser Antilles arc system. Since the Late Cretaceous, the inner undeformed portions of the Caribbean oceanic plateau (i.e. the Colombian and Venezuelan Basins) were trapped east of the Pacific subduction of the Chortis, Chorotega and Choco blocks, ultimately building the Central American Isthmus. From Tertiary to Present, continuous eastward movement of the Caribbean Plate with respect to the Americas, gave rise to transpression along both the northern and southern margins, marked by scattered and dismembered ophiolitic terranes

Adipose-derived stem cells: true or false? A different point of view

SPECIAL EDITORIA

Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real fixation point maps. One of our contributions is to detect the main differences between the aforementioned human visual systems related to color vision deficiencies by analyzing real fixation maps among people with and without color vision deficiencies. Another contribution is to provide a method to enhance color regions of the image by using a detailed color mapping of the segmented salient regions of the given image. The segmentation is performed by using the difference between the original input image and the corresponding color blind altered image. A second eye-tracking of color blind people with the images enhanced by using recoloring of segmented salient regions reveals that the real fixation points are then more coherent (up to 10%) with the normal visual system. The eye-tracking data collected during our experiments are in a publicly available dataset called Eye-Tracking of Color Vision Deficiencies

Toxoplasma gondii in raw milk from Sicily

Toxoplasma gondii tachyzoites shed in milk of infected animals are a potential source of human infection often underestimated. Furthermore, limited risk assessment studies have been carried out to evaluate the transmission of toxoplasmosis by milk consumption. In this frame the availability of few and often not validated analytical methods can be a major shortcoming when investigating the extent of milk contamination and the parasite viability. To address the issue, 1381 samples of raw milk from unknown sero-status cows, donkeys, sheep and goats were examined for the detection of T. gondii DNA by a real time PCR method targeting the 529bp repeating element. The protozoan DNA was detected in 67 samples of cow’s milk (4,93% and 35% individual and herd prevalence respectively) and in one sample of donkey milk. Allegedly, on farm cats cohabitation as well as extensive management in the cattle farms that tested positive, can be accounted for environmental loading and transmission of T. gondii oocysts that are the unique sources of infection for milk-producing animals. Food safety-wise, results are noteworthy since recently raw cow’s milk consumption has become increasingly popular with the spread of automatic raw milk vending machines. Albeit heating treatment before consumption is mandatory for consumers, neglect of this requirement cannot be ruled out and could lead the way for foodborne infection. This is particularly true in view of evidences that T. gondii tachyzoites in experimentally spiked cow’s milk samples could be able to survive in gastric fluids for long enough (1 h) before reaching the intestine and infect the host

A comparison between standard and crossfeed monopulse radars in presence of rough sea scattering and ship movements

Monopulse radars are widely used in tracking systems, due to their relative simplicity and theoretical precision, but the presence of multipath impairs the tracking capabilities of these radars, especially when multipath signals are strong, as in a naval environment. A special monopulse setup, the crossfeed, has been proposed in the past to provide an automatic cancellation from smooth sea multipath. In this contribution, the performances of such a system are analyzed in presence of rough sea scattering and compared with those of a standard monopulse setup. Particular attention is devoted to performance degradations due to possible phase errors in the passive network implementing the comparator and due to ship rolling and pitching. This latter requires a full 3D monopulse simulator for its correct evaluation

Working with children who are victims of abuse: Emotions and representations of professionals in residential children's communities

Professionals who work in residential children's communities face many difficulties and, when the hosted children have a history of abuse and maltreatment, the risk of vicarious traumatization and professional burn-out, which has a negative effect on the professional's work and well-being as well as on the effectiveness at work, is very high. This qualitative study aims to explore, via the content analysis of text recorded in some Photolangage® groups, the representations of social workers and educators in residential children's communities on the theme of work management of physical and sexual abuse victims. The participants were 37 social workers from 6 residential communities for 0-6 years old child in the region of Palermo (Italy). The analysis of the discourse revealed four main themes: "emotional responses", "difficulty in coping with emotions related to abuse", "relationship with the institutional network" and "work methods/strategies", which seem to guide and inform the social workers in our daily relationship with children. These results, which are in line with clinical observations, indicate the importance of supporting, through tools such as supervision and analysis of professional practices, professionals who work with maltreated and abused children, the only way to protect their well-being and the "therapeutic role" in the care and protection of children which they fulfil

One year of CNR-IMAA multi-wavelength Raman lidar measurements in coincidence with CALIPSO overpasses: Level 1 products comparison

At CNR-IMAA, an aerosol lidar system has operated since May 2000 in the framework of EARLINET (European Aerosol Research Lidar Network), the first lidar network for tropospheric aerosol study on a continental scale. High quality multi-wavelength measurements make this system a reference point for the validation of data products provided by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations), the first satellite-borne lidar specifically designed for aerosol and cloud study. Since 14 June 2006, dedicated measurements have been performed at CNR-IMAA in coincidence with CALIPSO overpasses. For the first time, results on 1-year comparisons between ground-based multi-wavelength Raman lidar measurements and corresponding CALIPSO lidar Level 1 profiles are presented. A methodology for the comparison is presented and discussed in detail. Night-time cases are considered to take advantage from Raman capability of the ground based lidar. Cases with the detection of cirrus clouds in CALIPSO data are separately analysed for taking into account multiple scattering effects. For cirrus cloud cases, few cases are available to draw any conclusions. For clear sky conditions, the comparison shows good performances of the CALIPSO on-board lidar: the mean relative difference between the ground-based and CALIPSO Level 1 measurements is always within its standard deviation at all altitudes, with a mean difference in the 3–8 km altitude range of (−2±12)%. At altitude ranges corresponding to the typical PBL height observed at CNR-IMAA, a mean difference of (−24±20)% is observed in CALIPSO data, probably due to the difference in the aerosol content at the location of PEARL and CALIPSO ground-track location. Finally, the mean differences are on average lower at all altitude ranges for the closest overpasses (at about 40 km) respect to the 80-km overpasses