Distribution of phytobenthos along the coast of Lebanon

A phytosociological study of the phytobenthos was carried out along the coast of Lebanon during 1996-97. Samples were collected seasonally at six sites, some of which showed distinct pollution signature. Quadrates of 0.04 m-2 were taken at selected stations fixed on transects perpendicular to the rocky shore and covering the supralittoral, the mediolittoral and infralittoral zones. The taxonomic composition, the abundance and species diversity of algal community were analysed in relation to environmental factors. A total of 230 taxa were identified during the period of survey. Several sources of pollution, resulted in the reduction of macroalgae biomass and of the taxonomic diversity. Several Indo-Pacific species were found within the different phytocoenoses of the area; most of them were introduced into the Levantine Basin through the Suez Canal. These species, that were introduced into the Eastern Mediterranean, formed permanent populations; some of them were highly spread and dominated over other endemic species or even they replaced them

Optimal processings design for synthetic aperture radar

Synthetic aperture radar (SAR) is a microwave imagery system capable ofproducing high resolution images by processing properly data collected by a relatively small antenna. In this papet the bi-dimensionnal received signal, using spatial coordinates, is formulated. The image is reconstructed by a two- dimensionnal filtering operation . We propose a straightforward derivation for the coherent sommation method (or bock-projection of range responses) and the 2-D azimuth matched filtering . The image quality is determined by that of the ambiguity fonction. This latter is analyzed and optimized for two performance criteria. First, for a matched filter receiver (maximal signal-to-noise ratio receiver), the optimal waveform is shown ta be a non linear FM pulse which autocorrelationfunction is a Taylor . The optimal azmiuth weighting fonction is related to that of Taylor by a Fourier transform . Second, for a Wiener filter (least mean-squares receiver), we show that the optimal waveform is the firstprolate spheroidal fonction . The single-hit measurement of the scattering matrix by mean of two optimal orthogonal waves is discussed . Resolutions, SNR as well as ambiguities, are specified .Le radar à visée latérale et à ouverture synthétique est un système d'imagerie micro-onde capable de produire des images de très haute résolution des terrains, et ceci à partir d'un traitement approprié des signaux reçus par une antenne de faible dimension, Dans cet article, nous présentons la formulation exacte du signal reçu, ainsi que les traitements associés afin de former l'image. On met en évidence l'équivalence entre la méthode de la sommation cohérente et le filtrage adapté bidimensionnel en azimut. La qualité de l'image ainsi formée est déterminée par celle de la fonction d'ambiguït

Diferencias estacionales entre tropopausas térmicas calculadas usando perfiles verticales de temperatura a partir de niveles significativos y estándar de radiosondeos para la red aerológica de Sudamérica

Se llevó a cabo un estudio de diferencias entre dos tropopausas térmicas sobre 59 estaciones aerológicas de Sudamérica. La tropopausa térmica primigenia, llamada lapse rate tropopause (LRT) y obtenida de perfiles verticales de temperatura en niveles significativos incluidos en los radiosondeos siguiendo la definición de la Organización Meteorológica Mundial (World Meteorological Organization, WMO), fue comparada con la tropopausa estimada de los niveles estándar (LRTM) con un algoritmo que está de acuerdo con la definición de la WMO. El período de estudio comprende enero 1973‒diciembre 2019. Las comparaciones entre la LRT y la LRTM se llevaron a cabo de manera estacional para presión, altura y temperatura. Los resultados fueron organizados en bandas latitudinales de 5º de ancho. Por bandas zonales la LRTM está, en promedio, por debajo o por encima de la LRT dependiendo de la banda, y en general ambas tropopausas son estadísticamente distintas. Con el objetivo de estimar si existe una relación entre ellas se calculó el coeficiente de correlación de Spearman entre las mismas variables de LRTM y LRT, los cuales resultaron positivos por lo que las variables correlacionadas pueden vincularse a través de funciones monótonas crecientes. Se escogió una función lineal y las pendientes y ordenadas al origen fueron obtenidas para cada banda de latitud. Las variables de la LRTM tomadas como predictores permiten así conocer las correspondientes a la LRT estimada (LRT*). La discrepancia entre LRT* y LRT fueron cuantificadas con el error cuadrático medio, cuya maximización tiene lugar en la región de influencia del jet subtropical.An analysis on the differences between two thermal tropopauses at 59 South American upper-air stations was carried out. The original lapse rate tropopause (LRT) derived from significant-level radiosonde temperature profiles following the World Meteorological Organization (WMO) definition was compared with the tropopause estimated from radiosonde mandatory levels (LRTM) with a WMO-compliant algorithm. The study period encompasses January 1973–December 2019. The comparisons between the LRT and the LRTM were performed on a seasonal basis for pressure, height and temperature and the results were organized into latitudinal bands of 5° width. On average, the LRTM locates below or above the LRT, depending on the band considered, and in general the both tropopauses are statistically different. The Spearman’s correlation coefficients between the same LRTM and LRT variables were calculated in order to estimate whether there exists a relation between them. The coefficients resulted positive so the correlated variables can be related through monotonic increasing functions. A linear function was selected and the slopes and the intercepts for this relation were provided at each latitudinal band. Taking the LRTM variables as predictors enables the obtention of the corresponding LRT variables. The matching between the LRT and the LRTM-derived LRT was addressed through root mean squares, whose maximization occurs in the subtropical jet’s region of influence.Asociación Argentina de Geofísicos y Geodesta

Diferencias estacionales entre tropopausas térmicas calculadas usando perfiles verticales de temperatura a partir de niveles significativos y estándar de radiosondeos para la red aerológica de Sudamérica

Se llevó a cabo un estudio de diferencias entre dos tropopausas térmicas sobre 59 estaciones aerológicas de Sudamérica. La tropopausa térmica primigenia, llamada lapse rate tropopause (LRT) y obtenida de perfiles verticales de temperatura en niveles significativos incluidos en los radiosondeos siguiendo la definición de la Organización Meteorológica Mundial (World Meteorological Organization, WMO), fue comparada con la tropopausa estimada de los niveles estándar (LRTM) con un algoritmo que está de acuerdo con la definición de la WMO. El período de estudio comprende enero 1973‒diciembre 2019. Las comparaciones entre la LRT y la LRTM se llevaron a cabo de manera estacional para presión, altura y temperatura. Los resultados fueron organizados en bandas latitudinales de 5º de ancho. Por bandas zonales la LRTM está, en promedio, por debajo o por encima de la LRT dependiendo de la banda, y en general ambas tropopausas son estadísticamente distintas. Con el objetivo de estimar si existe una relación entre ellas se calculó el coeficiente de correlación de Spearman entre las mismas variables de LRTM y LRT, los cuales resultaron positivos por lo que las variables correlacionadas pueden vincularse a través de funciones monótonas crecientes. Se escogió una función lineal y las pendientes y ordenadas al origen fueron obtenidas para cada banda de latitud. Las variables de la LRTM tomadas como predictores permiten así conocer las correspondientes a la LRT estimada (LRT*). La discrepancia entre LRT* y LRT fueron cuantificadas con el error cuadrático medio, cuya maximización tiene lugar en la región de influencia del jet subtropical.An analysis on the differences between two thermal tropopauses at 59 South American upper-air stations was carried out. The original lapse rate tropopause (LRT) derived from significant-level radiosonde temperature profiles following the World Meteorological Organization (WMO) definition was compared with the tropopause estimated from radiosonde mandatory levels (LRTM) with a WMO-compliant algorithm. The study period encompasses January 1973–December 2019. The comparisons between the LRT and the LRTM were performed on a seasonal basis for pressure, height and temperature and the results were organized into latitudinal bands of 5° width. On average, the LRTM locates below or above the LRT, depending on the band considered, and in general the both tropopauses are statistically different. The Spearman’s correlation coefficients between the same LRTM and LRT variables were calculated in order to estimate whether there exists a relation between them. The coefficients resulted positive so the correlated variables can be related through monotonic increasing functions. A linear function was selected and the slopes and the intercepts for this relation were provided at each latitudinal band. Taking the LRTM variables as predictors enables the obtention of the corresponding LRT variables. The matching between the LRT and the LRTM-derived LRT was addressed through root mean squares, whose maximization occurs in the subtropical jet’s region of influence.Asociación Argentina de Geofísicos y Geodesta

Effect of increasing age on percutaneous coronary intervention vs coronary artery bypass grafting in older adults with unprotected left main coronary artery disease: A meta-analysis and meta-regression

Background: Older adults (≥70-year-old) are under-represented in the published data pertaining to unprotected left main coronary artery disease (ULMCAD).Hypothesis: Percutaneous coronary intervention (PCI) might be comparable to coronary artery bypass grafting (CABG) for revascularization of ULMCAD.Methods: We compared PCI versus CABG in older adults with ULMCAD with an aggregate data meta-analyses (4880 patients) of clinical outcomes [all-cause mortality, myocardial infarction (MI), repeat revascularization, stroke and major adverse cardiac and cerebrovascular events(MACCE)] at 30 days, 12-24 months & ≥36 months in patients with mean age ≥70 years and ULMCAD. A meta-regression analysis evaluated the effect of age on mortality after PCI. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using random-effects model.Results: All-cause mortality between PCI and CABG was comparable at 30-days (OR0.77, 95% CI 0.42- 1.41) and 12-24-months (OR 1.22, 95% CI 0.78-1.93). PCI was associated with a markedly lower rate of stroke at 30-day follow-up in octogenarians (OR 0.14, 95% CI 0.02-0.76) but an overall higher rate of repeat revascularization. At ≥36-months, MACCE (OR 1.26,95% CI 0.99-1.60) and all-cause mortality (OR 1.39, 95% CI 1.00-1.93) showed a trend favoring CABG but did not reach statistical significance. On meta-regression, PCI was associated with a higher mortality with advancing age (coefficient=0.1033, p=0.042).Conclusions: PCI was associated with a markedly lower rate of early stroke in octogenarians as compared to CABG. All-cause mortality was comparable between the two arms with a trend favoring CABG at ≥36-months.PCI was however associated with increasing mortality with advancing age as compared to CABG

Global existence for semilinear reaction-diffusion systems on evolving domains

We present global existence results for solutions of reaction-diffusion systems on evolving domains. Global existence results for a class of reaction-diffusion systems on fixed domains are extended to the same systems posed on spatially linear isotropically evolving domains. The results hold without any assumptions on the sign of the growth rate. The analysis is valid for many systems that commonly arise in the theory of pattern formation. We present numerical results illustrating our theoretical findings.Comment: 24 pages, 3 figure

Impediments to eye transplantation: Ocular viability following optic-nerve transection or enucleation

Maintenance of ocular viability is one of the major impediments to successful whole-eye transplantation. This review provides a comprehensive understanding of the current literature to help guide future studies in order to overcome this hurdle. A systematic multistage review of published literature was performed. Three specific questions were addressed: (1) Is recovery of visual function following eye transplantation greater in cold-blooded vertebrates when compared with mammals? (2) Is outer retina function following enucleation and reperfusion improved compared with enucleation alone? (3) Following optic-nerve transection, is there a correlation between retinal ganglion cell (RGC) survival and either time after transection or proximity of the transection to the globe? In a majority of the studies performed in the literature, recovery of visual function can occur after whole-eye transplantation in cold-blooded vertebrates. Following enucleation (and reperfusion), outer retinal function is maintained from 4 to 9 h. RGC survival following optic-nerve transection is inversely related to both the time since transection and the proximity of transection to the globe. Lastly, neurotrophins can increase RGC survival following optic-nerve transection. This review of the literature suggests that the use of a donor eye is feasible for whole-eye transplantation.published_or_final_versio

Transitional B cell cytokines predict renal allograft outcomes

Early immunological biomarkers that predict rejection and chronic allograft loss are needed to inform preemptive therapy and improve long-term outcomes. Here, we prospectively examined the ratio of interleukin-10 (IL-10) to tumor necrosis factor–α (TNFα) produced by transitional-1 B cells (T1B) 3 months after transplantation as a predictive biomarker for clinical and subclinical renal allograft rejection and subsequent clinical course. In both Training (n = 162) and Internal Validation (n = 82) Sets, the T1B IL-10/TNFα ratio 3 months after transplantation predicted both clinical and subclinical rejection anytime in the first year. The biomarker also predicted subsequent late rejection with a lead time averaging 8 months. Among biomarker high-risk patients, 60% had early rejection, of which 48% recurred later in the first posttransplant year. Among high-risk patients without early rejection, 74% developed rejection later in the first year. In contrast, only 5% of low-risk patients had early and 5% late rejection. The biomarker also predicted rejection in an External Validation Set (n = 95) and in key patient subgroups, confirming generalizability. Biomarker high-risk patients exhibited progressively worse renal function and decreased 5-year graft survival compared to low-risk patients. Treatment of B cells with anti-TNFα in vitro augmented the IL-10/TNFα ratio, restored regulatory activity, and inhibited plasmablast differentiation. To conclude, the T1B IL-10/TNFα ratio was validated as a strong predictive biomarker of renal allograft outcomes and provides a rationale for preemptive therapeutic intervention with TNF blockade

Early 21st century cyclone climatology: a 3D perspective. Basic characterization

Extratropical cyclones are a relevant feature in the climate at middle and high latitudes. Despite their relevance, most of studies typically focus on cyclones identified at a single atmospheric level and on events close to the surface. This paper provides a new perspective on the Southern Hemisphere cyclone events based on the multilevel cyclone tracking algorithm STACKER. The algorithm, using relative vorticity, detects the raw tracks at single levels and objectively combine them to provide the 3D events and their evolutionary timeline. As result, 3D cyclone climatology, based on ECMWF Reanalysis ERA-I data from 12 pressure levels in the troposphere and lowermost stratosphere is presented. To the best of our knowledge this is the first analysis carried out throughout the troposphere and the lowermost extratropical/subpolar stratosphere in order to give a comprehensive picture of the cyclone events as physical entities throughout their lifetime. Cyclone properties analysed are track densities, translational velocity, vorticity and lifetimes. For the subtropical and extrattropical SH, results support many previous ideas about cyclone characteristics, but new insights are also obtained. A total of 58231 multilevel cyclone events lasting at least 2 days were detected, with vertical structures spanning two or more levels. This means an average of 303 cyclone events of all types per month, between 2001 and 2017, disregarding seasonality. Results shows that the lowermost level of cyclones are most frequently detected at 925 and 700 hPa, Considering that cyclonic systems can be grouped into families, results per month on average, show that shallow systems are the most frequent events with approximately 248 systems detected, followed by 43 intermediates and 11 deep events. Shallow and deep systems have a large percentage of events with genesis at 925 and 700hPa. Density statistics show that shallow events are present at all latitude ranges mostly poleward 30ºS with high and medium intensities, while intermediate ones are mostly restricted to mid-latitudes and deep events are mostly confined to sub-polar and polar latitudes. Cyclones over Antarctica seems to be mostly intermediates and deeps, with longer lifetimes and lower velocities

American Academy of Optometry Microbial Keratitis Think Tank

SIGNIFICANCE Think Tank 2019 affirmed that the rate of infection associated with contact lenses has not changed in several decades. Also, there is a trend toward more serious infections associated with Acanthamoeba and fungi. The growing use of contact lenses in children demands our attention with surveillance and case-control studies. PURPOSE The American Academy of Optometry (AAO) gathered researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting. METHODS Experts presented within four sessions. Session 1 covered the epidemiology of microbial keratitis, pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease. Session 2 covered nonbacterial forms of keratitis in contact lens wearers. Session 3 covered future needs, challenges, and research questions in relation to microbial keratitis in youth and myopia control, microbiome, antimicrobial surfaces, and genetic susceptibility. Session 4 covered compliance and communication imperatives. RESULTS The absolute rate of microbial keratitis has remained very consistent for three decades despite new technologies, and extended wear significantly increases the risk. Improved oxygen delivery afforded by silicone hydrogel lenses has not impacted the rates, and although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis. Overnight orthokeratology lenses may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into host microbiome and genetic susceptibility may uncover new theories. More studies such as case-control designs suited for rare diseases and registries are needed. CONCLUSIONS The first annual AAO Think Tank acknowledged that the risk of microbial keratitis has not decreased over decades, despite innovation. Important questions and research directions remain