Microsatellite instability in gastric cancer is associated with tumor location and family history in a high-risk population from Tuscany

We studied the presence of microsatellite instability (MSI) in a series of 108 gastric cancers (GCs) previously identified in an epidemiological study carried out in a high-risk area around Florence, To investigate associations between MSI and GC family history, 34 cases (31.5%) who had a GC-affected first-degree relative were included in the series, A family history positive for colorectal cancer was reported quite rarely (5.6%). The analysis of 6 microsatellite loci in DNA from paired normal tissue and tumor samples microdissected from paraffin-embedded specimens revealed varying degrees of instability: 56 cases (51.8%) did not show instability at any of the 6 loci; 19 (17.6%) showed instability at 1 locus; 16 (14.8%) showed instability at 2 loci; 11 (10.2%) showed instability at 3 loci; 4 (3.7%) showed instability at 4 loci; and 2 (1.9%) showed instability at 5 loci, The replication error-positive (RER+) phenotype, defined as the presence of MSI at 2 or more loci, had a frequency of 30.6% (33 of 108) and tended to be positively associated with female sex, intestinal histological type, advanced tumor stage, vascular invasion, positive GC family history, and blood group of A type, No correlation emerged between age at diagnosis and RER+ phenotype, whereas a significant association with the RER+ phenotype was shown by the antral location. A multivariate analysis adjusting for a selected group of potential confounding factors confirmed the strong association of the RER+ phenotype with the antral location (P = 0.001) and with a positive GC family history (P < 0.05). Survival analyses at 5 and 8 years showed no difference between RER+ and RER-patients, even when corrected for stage distribution. By the microdissection technique, we also used microsatellite allele patterns to investigate intratumoral heterogeneity and genetic relationships between tumors and adjacent dysplasia and/or intestinal metaplasia. Areas of metaplasia and dysplasia demonstrated MSI only in cases with MSI-positive tumors, In MSI-positive tumors, there was consistent evidence of intratumoral microsatellite allele heterogeneity, indicating the presence of genetically divergent tumor cell clones within the same neoplasm

Indici per la valutazione della qualit? ecologica dei laghi

Collection of methods to evaluate lake quality using biological element

​​Observing Antarctic Bottom Water in the Southern Ocean​

Dense, cold waters formed on Antarctic continental shelves descend along the Antarctic continental margin, where they mix with other Southern Ocean waters to form Antarctic Bottom Water (AABW). AABW then spreads into the deepest parts of all major ocean basins, isolating heat and carbon from the atmosphere for centuries. Despite AABW’s key role in regulating Earth’s climate on long time scales and in recording Southern Ocean conditions, AABW remains poorly observed. This lack of observational data is mostly due to two factors. First, AABW originates on the Antarctic continental shelf and slope where in situ measurements are limited and ocean observations by satellites are hampered by persistent sea ice cover and long periods of darkness in winter. Second, north of the Antarctic continental slope, AABW is found below approximately 2 km depth, where in situ observations are also scarce and satellites cannot provide direct measurements. Here, we review progress made during the past decades in observing AABW. We describe 1) long-term monitoring obtained by moorings, by ship-based surveys, and beneath ice shelves through bore holes; 2) the recent development of autonomous observing tools in coastal Antarctic and deep ocean systems; and 3) alternative approaches including data assimilation models and satellite-derived proxies. The variety of approaches is beginning to transform our understanding of AABW, including its formation processes, temporal variability, and contribution to the lower limb of the global ocean meridional overturning circulation. In particular, these observations highlight the key role played by winds, sea ice, and the Antarctic Ice Sheet in AABW-related processes. We conclude by discussing future avenues for observing and understanding AABW, impressing the need for a sustained and coordinated observing system

A turbulent story: role of diapycnal mixing in the ocean overturning circulation and tracer distribution

Natural and anthropogenic heat and carbon, as well as other climatically and biologically important tracers, enter the deep global overturning circulation mainly during the formation of dense waters at the high latitudes around Antarctica and in the North Atlantic. Through the transport, sequestration and upwelling of tracers, the global overturning circulation contributes to the regulation and variability of our climate system. This thesis investigates the role of diapycnal (cross-density) mixing in regulating the deep ocean overturning circulation and the distribution of tracers carried within it. Diapycnal mixing is here quantified through a combination of pre-existing estimates inferred from different observational sources, namely Argo floats, CTD casts combined with microstructure profiles, bulk estimates from an inverse model and observation-based theoretical estimates of the mixing generated by internal tides and lee waves. Firstly, it is shown that the upwelling of abyssal waters is the residual of large near-boundary upwelling and interior downwelling, the patterns of which are highly sensitive to the specifics of the energy pathways from tides and geostrophic motions to internal waves and thereafter to mixing and dissipation. Secondly, we focus on the Atlantic Ocean, where we investigate the role of mixing in the closure of the Atlantic meridional overturning circulation. Diapycnal mixing is shown to contribute only marginally to the conversion of the dense waters formed in the North Atlantic into lighter northward-flowing waters within the Atlantic basin, but it plays a crucial role in the distribution of tracers carried from the North Atlantic to the Southern Ocean. The impact of mixing on tracer distributions is analysed both from observational mixing estimates and from pre-existing numerical simulations of a tracer release experiment in a quasi-realistic Atlantic sector model. As a tracer is carried southward by the Atlantic overturning circulation, we quantify its exchange between different water masses. The tracer transport and exchange rates are key in determining in which density classes tracers are going to upwell in the Southern Ocean, therefore determining which pathway they will follow in the global overturning circulation

Meanders and eddy formation by a buoyant coastal current flowing over a sloping topography

This study investigates the linear and non-linear instability of a buoyant coastal current flowing along a sloping topography. In fact, the bathymetry strongly impacts the formation of meanders or eddies and leads to different dynamical regimes that can both enhance or prevent the cross-shore transport. We use the Regional Ocean Modeling System (ROMS) to run simulations in an idealized channel configuration, using a fixed coastal current structure and testing its unstable evolution for various depths and topographic slopes. The experiments are integrated beyond the linear stage of the instability, since our focus is on the non-linear end state, namely the formation of coastal eddies or meanders, to classify the dynamical regimes. We find three non-linear end states, whose properties cannot be deduced solely from the linear instability analysis. They correspond to a quasi-stable coastal current, the propagation of coastal meanders, and the formation of coherent eddies. We show that the topographic parameter T-p, defined as the ratio of the topographic Rossby wave speed over the current speed, plays a key role in controlling the amplitude of the unstable cross-shore perturbations. This result emphasizes the limitations of linear stability analysis to predict the formation of coastal eddies, because it does not account for the non-linear saturation of the cross-shore perturbations, which is predominant for large negative T-p values. We show that a second dimensionless parameter, the vertical aspect ratio gamma, controls the transition from meanders to coherent eddies. We suggest the use of the parameter space (T-p, gamma) to describe the emergence of coastal eddies or meanders from an unstable buoyant current. By knowing the values of T-p and gamma for an observed flow, which can be calculated from hydrological sections, we can identify which non-linear end state characterizes that flow - namely if it is quasi-stable, meanders, or forms eddies

Mountains to climb: on the role of seamounts in upwelling of deep ocean waters

Ocean turbulent mixing exerts an important control on the rate and structure of the overturning circulation. Recent observational evidence suggests, however, that there could be a mismatch between the observed intensity of mixing integrated over basin or global scales, and the net mixing required to sustain the overturning's deep upwelling limb. Here, we investigate the hitherto largely overlooked role of tens of thousands of seamounts in resolving this discrepancy. Dynamical theory indicates that seamounts may stir and mix deep waters by generating lee waves and topographic wake vortices. At low latitudes, this is enhanced by a layered vortex regime in the wakes. We consider three case studies (in the equatorial zone, Southern Ocean and Gulf Stream) that are predicted by theory to be representative of, respectively, a layered vortex, barotropic wake, and hybrid regimes, and corroborate theoretical scalings of mixing in each case with a realistic regional ocean model. We then apply such scalings to a global seamount dataset and an ocean climatology to show that seamount-generated mixing makes a leading-order contribution to the global upwelling of deep waters. Our work thus brings seamounts to the fore of the deep-ocean mixing problem, and urges observational, theoretical and modeling efforts toward incorporating the seamounts' mixing effects in conceptual and numerical models of the ocean circulation

A spatial multi-criteria evaluation for site selection of offshore marine fish farm in the Ligurian Sea, Italy

Mariculture is a relatively new activity that is expanding globally and interacts with other coastal uses. Therefore, it is necessary to allocate suitable sites from environmental, economic and social points of view, involving different stakeholders in the decision-making process. In particular, in the Ligurian Sea (Italy), for its environmental characteristics and tradition, fish farming should be further boosted and an accurate marine spatial planning should be done. This paper presents a spatial multi-criteria evaluation (SMCE) addressed to identify suitable areas for siting offshore medium size fish farms in the Ligurian Sea at the regional scale. The SMCE procedure follows an integrated approach that can be potentially adapted and applied to any coastal system. The site selection is based on the definition of criteria that assess their suitability and on conditions related to the entire study area. Suitability values are ranked on a scale from 1 (suitable) to 10 (optimal). More than 9000 ha were identified and almost 40% of this area gets high suitability values, from 7 to 9, pointing out the untapped potential for Ligurian marine coastal zone. Results demonstrate that our SMCE, and in particular its procedure, allows identifying the most suitable areas in an easy and quick way and solving effectively the complex spatial problem of suitable site se- lection for fish farming

Significance of Diapycnal Mixing Within the Atlantic Meridional Overturning Circulation

Diapycnal mixing shapes the distribution of climatically important tracers, such as heat and carbon, as these are carried by dense water masses in the ocean interior. Here, we analyze a suite of observation-based estimates of diapycnal mixing to assess its role within the Atlantic Meridional Overturning Circulation (AMOC). The rate of water mass transformation in the Atlantic Ocean's interior shows that there is a robust buoyancy increase in the North Atlantic Deep Water (NADW, neutral density γn ≃ 27.6–28.15), with a diapycnal circulation of 0.5–8 Sv between 48°N and 32°S in the Atlantic Ocean. Moreover, tracers within the southward-flowing NADW may undergo a substantial diapycnal transfer, equivalent to a vertical displacement of hundreds of meters in the vertical. This result, confirmed with a zonally averaged numerical model of the AMOC, indicates that mixing can alter where tracers upwell in the Southern Ocean, ultimately affecting their global pathways and ventilation timescales. These results point to the need for a realistic mixing representation in climate models in order to understand and credibly project the ongoing climate change. Key Points The cross-density mixing of water and tracers is quantified from observation-based estimates and numerical simulations in the Atlantic Ocean A net 0.5–8 Sv of North Atlantic Deep Water upwells diapycnally in the Atlantic Ocean (48°N–32°S), comprised of larger regional up/downwelling fluxes Tracer mixing in the deep Atlantic Ocean can significantly modify pathways and ventilation rates of tracers upwelling in the Southern Ocean Plain Language Summary The Atlantic Ocean meridional overturning circulation plays a key role in regulating the global heat and carbon budgets by inter-hemispheric transport of anthropogenic and natural tracers as well as water masses. While most of this transport occurs along nearly horizontal density surfaces in the ocean interior, vertical transport across density levels is key to bringing deep waters back to the surface. Such cross-density transport is facilitated mainly by the internal waves breaking into turbulence and near boundary processes. This work employs a host of observation-based estimates of turbulence in the Atlantic Ocean to (a) better quantify the contribution of cross-density mixing to the inter-hemispheric Atlantic circulation, and (b) discuss the potential implications for pathways and residence times of tracers carried from the North Atlantic to the Southern Ocean. This work calls for a more careful representation of turbulence-induced vertical mixing within the Atlantic Ocean in climate models to better understand and project the ongoing climate change

Musulmanes et féministes en Grande-Bretagne

Le terrorisme international et les attentats de Londres en 2005 ont mis un terme à une relative neutralité politique de l’islam en Grande-Bretagne. Ce dossier analyse comment les femmes musulmanes britanniques se mobilisent en tentant de concilier identité et culture musulmane, défense des droits des femmes, activisme civique et politique. The international terrorism and the attempts of London in 2005 put an end to a relative political neutrality of the Islam in Great Britain. This file analyzes how the British Muslim women mobilize by trying to reconcile identity and culture Muslim, defense of the rights of the women, civic and political activism