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The southern Red Sea is genetically distinct from the rest of the basin; yet the reasons responsible for this genetic separation remain unclear. Connectivity is a vital process for the exchange of individuals and genes among geographically separated populations, and is necessary for maintaining biodiversity and resilience in coral reef ecosystems. Here, using long-term, high-resolution, 3-D backward particle tracking simulations, we investigate the physical connectivity of coral reefs in the southern Red Sea with neighbouring regions. Overall, the simulation results reveal that the southern Red Sea coral reefs are more physically connected with regions in the Indian Ocean (e.g., the Gulf of Aden) than with the northern part of the basin. The identified connectivity exhibits a distinct monsoon-related seasonality. Though beyond the country boundaries, relatively remote regions of the Indian Ocean may have a substantial impact on the southern Red Sea coral reef regions, and this should be taken into consideration when establishing conservation strategies for these vulnerable biodiversity hot-spots.

The Red Sea, home to the second-longest coral reef system in the world, is a vital resource for the Kingdom of Saudi Arabia. The Red Sea provides 90% of the Kingdom’s potable water by desalinization, supporting tourism, shipping, aquaculture, and fishing industries, which together contribute about 10%–20% of the country’s GDP. All these activities, and those elsewhere in the Red Sea region, critically depend on oceanic and atmospheric conditions. At a time of mega-development projects along the Red Sea coast, and global warming, authorities are working on optimizing the harnessing of environmental resources, including renewable energy and rainwater harvesting. All these require high-resolution weather and climate information. Toward this end, we have undertaken a multipronged research and development activity in which we are developing an integrated data-driven regional coupled modeling system. The telescopically nested components include 5-km- to 600-m-resolution atmospheric models to address weather and climate challenges, 4-km- to 50-m-resolution ocean models with regional and coastal configurations to simulate and predict the general and mesoscale circulation, 4-km- to 100-m-resolution ecosystem models to simulate the biogeochemistry, and 1-km- to 50-m-resolution wave models. In addition, a complementary probabilistic transport modeling system predicts dispersion of contaminant plumes, oil spill, and marine ecosystem connectivity. Advanced ensemble data assimilation capabilities have also been implemented for accurate forecasting. Resulting achievements include significant advancement in our understanding of the regional circulation and its connection to the global climate, development, and validation of long-term Red Sea regional atmospheric–oceanic–wave reanalyses and forecasting capacities. These products are being extensively used by academia, government, and industry in various weather and marine studies and operations, environmental policies, renewable energy applications, impact assessment, flood forecasting, and more.

Using satellite observations, this study uncovers the biophysical drivers of the lucrative chokka squid fishery in South Africa over the last two decades (1998–2017) and addresses their potential links with low squid catches. Chokka squid fishing is crucial to the economic wellbeing of local communities. However, the squid biomass is prone to considerable fluctuations, including abrupt declines with negative socio-economic impacts. We show that the squid catch is significantly and positively correlated with satellite-derived chlorophyll-a (Chl-a, an index of phytoplankton biomass) from year to year in South African coastal waters. Two main phytoplankton blooms are observed to occur seasonally in the austral spring and autumn, peaking in October and April, respectively. From October to April, phytoplankton abundance is influenced by the occurrence of wind-driven upwelling over the South African west coast (southern Benguela) and the central Agulhas Bank (so-called Cold Ridge upwelling), while the surface currents appear more important for shelf edge processes and advection along the Cold Ridge on shorter timescales. Low squid catches are observed in 2001 and 2013 and linked to declines in Chl-a induced by weak winds and relaxed negative wind stress curl over the southwest coast in 2001, and over the southwest coast and the central Agulhas Bank in 2013. Phytoplankton phenology (bloom timing) analysis reveals absent, or shorter and delayed blooms, over the Benguela upwelling region in 2001 and both the Benguela and Cold Ridge upwelling areas in 2013. In contrast, the high catch years of 2004 and 2009, associated with elevated Chl-a, coincide with early and/or prolonged seasonal blooms. These are induced by strong winds over the Benguela upwelling and Cold Ridge areas in 2004, and by intensified negative wind stress curl over the Benguela upwelling area in 2009. These results show that the squid catch fluctuations are potentially predictable and could support policymakers seeking to improve their planning of adaptation strategies and risk mitigation.

Lagrangian analysis is becoming increasingly important to better understand the ocean's biological and biogeochemical cycles. Yet, biologists and chemists often lack the technical skills required to set up such analyses. Here, we present a new product of pre-computed ocean Lagrangian trajectories (OLTraj) targeting non-expert users, and demonstrate how to use it by means of worked examples. OLTraj is based on satellite-derived geostrophic currents, which allows one to directly compare it with other in-situ or satellite products. We anticipate that OLTraj will foster a new interest in Lagrangian applications in ocean biology and biogeochemistry.

The timing of phytoplankton growth (phenology) in tropical oceans is a crucial factor influencing the survival rates of higher trophic levels, food web structure and the functioning of coral reef ecosystems. Phytoplankton phenology is thus categorised as an ‘ecosystem indicator’, which can be utilised to assess ecosystem health in response to environmental and climatic perturbations. Ocean-colour remote sensing is currently the only technique providing global, long-term, synoptic estimates of phenology. However, due to limited available in situ datasets, studies dedicated to the validation of satellite-derived phenology metrics are sparse. The recent development of autonomous oceanographic observation platforms provides an opportunity to bridge this gap. Here, we use satellite-derived surface chlorophyll-a (Chl-a) observations, in conjunction with a Biogeochemical-Argo dataset, to assess the capability of remote sensing to estimate phytoplankton phenology metrics in the northern Red Sea – a typical tropical marine ecosystem. We find that phenology metrics derived from both contemporary platforms match with a high degree of precision (within the same 5-day period). The remotely-sensed surface signatures reflect the overall water column dynamics and successfully capture Chl-a variability related to convective mixing. Our findings offer important insights into the capability of remote sensing for monitoring food availability in tropical marine ecosystems, and support the use of satellite-derived phenology as an ecosystem indicator for marine management strategies in regions with limited data availability.

In the tropics, thermal stratification (during warm conditions) may contribute to a shallowing of the mixed layer above the nutricline and a reduction in the transfer of nutrients to the surface lit-layer, ultimately limiting phytoplankton growth. Using remotely sensed observations and modelled datasets, we study such linkages in the northern Red Sea (NRS) - a typical tropical marine ecosystem. We assess the interannual variability (1998–2015) of both phytoplankton biomass and phenological indices (timing of bloom initiation, duration and termination) in relation to regional warming. We demonstrate that warmer conditions in the NRS are associated with substantially weaker winter phytoplankton blooms, which initiate later, terminate earlier and are shorter in their overall duration (~ 4 weeks). These alterations are directly linked with the strength of atmospheric forcing (air-sea heat fluxes) and vertical stratification (mixed layer depth [MLD]). The interannual variability of sea surface temperature (SST) is found to be a good indicator of phytoplankton abundance, but appears to be less important for predicting bloom timing. These findings suggest that future climate warming scenarios may have a two-fold impact on phytoplankton growth in tropical marine ecosystems: 1) a reduction in phytoplankton abundance and 2) alterations in the timing of seasonal phytoplankton blooms.

Harmful Algal Blooms (HABs) are of global concern, as their presence is often associated with socio-economic and environmental issues including impacts on public health, aquaculture and fisheries. Therefore, monitoring the occurrence and succession of HABs is fundamental for managing coastal regions around the world. Yet, due to the lack of adequate in situ measurements, the detection of HABs in coastal marine ecosystems remains challenging. Sensors on-board satellite platforms have sampled the Earth synoptically for decades, offering an alternative, cost-effective approach to routinely detect and monitor phytoplankton. The Red Sea, a large marine ecosystem characterised by extensive coral reefs, high levels of biodiversity and endemism, and a growing aquaculture industry, is one such region where knowledge of HABs is limited. Here, using high-resolution satellite remote sensing observations (1km, MODIS-Aqua) and a second-order derivative approach, in conjunction with available in situ datasets, we investigate for the first time the capability of a remote sensing model to detect and monitor HABs in the Red Sea. The model is able to successfully detect and generate maps of HABs associated with different phytoplankton functional types, matching concurrent in situ data remarkably well. We also acknowledge the limitations of using a remote-sensing based approach and show that regardless of a HAB's spatial coverage, the model is only capable of detecting the presence of a HAB when the Chl-a concentrations exceed a minimum value of ~ 1 mg m-3. Despite the difficulties in detecting HABs at lower concentrations, and identifying species toxicity levels (only possible through in situ measurements), the proposed method has the potential to map the reported spatial distribution of several HAB species over the last two decades. Such information is essential for the regional economy (i.e., aquaculture, fisheries & tourism), and will support the management and sustainability of the Red Sea's coastal economic zone.

The Gulf of Aden, situated in the northwest Arabian Sea and linked to the Red Sea, is a relatively unexplored ecosystem. Understanding of large-scale biological dynamics is limited by the lack of adequate datasets. In this study, we analyse 15 years of remotely-sensed chlorophyll-a data (Chl- a , an index of phytoplankton biomass) acquired from the Ocean Colour Climate Change Initiative (OC-CCI) of the European Space Agency (ESA). The improved spatial coverage of OC-CCI data in the Gulf of Aden allows, for the first time, an investigation into the full seasonal succession of phytoplankton biomass. Analysis of indices of phytoplankton phenology (bloom timing) reveals distinct phytoplankton growth periods in different parts of the gulf: a large peak during August (mid-summer) in the western part of the gulf, and a smaller peak during November (mid-autumn) in the lower central gulf and along the southern coastline. The summer bloom develops rapidly at the beginning of July, and its peak is approximately three times higher than that of the autumnal bloom. Remotely-sensed sea-surface temperature (SST), wind-stress curl, vertical nutrient profiles and geostrophic currents inferred from the sea-level anomaly, were analysed to examine the underlying physical mechanisms that control phytoplankton growth. During summer, the prevailing southwesterlies cause upwelling along the northern coastline of the gulf (Yemen), leading to an increase in nutrient availability and enhancing phytoplankton growth along the coastline and in the western part of the gulf. In contrast, in the central region of the gulf, lowest concentrations of Chl- a are observed during summer, due to strong downwelling caused by a mesoscale anticyclonic eddy. During autumn, the prevailing northeasterlies enable upwelling along the southern coastline (Somalia) causing local nutrient enrichment in the euphotic zone, leading to higher levels of phytoplankton biomass along the coastline and in the lower central gulf. The monsoon wind reversal is shown to play a key role in controlling phytoplankton growth in different regions of the Gulf of Aden.

Knowledge on large-scale biological processes in the southern Red Sea is relatively limited, primarily due to the scarce in situ, and satellite-derived chlorophyll-a (Chl-a) datasets. During summer, adverse atmospheric conditions in the southern Red Sea (haze and clouds) have long severely limited the retrieval of satellite ocean colour observations. Recently, a new merged ocean colour product developed by the European Space Agency (ESA)-the Ocean Color Climate Change Initiative (OC-CCI)-has substantially improved the southern Red Sea coverage of Chl-a, allowing the discovery of unexpected intense summer blooms. Here we provide the first detailed description of their spatiotemporal distribution and report the mechanisms regulating them. During summer, the monsoon-driven wind reversal modifies the circulation dynamics at the Bab-el-Mandeb strait, leading to a subsurface influx of colder, fresher, nutrient-rich water from the Indian Ocean. Using satellite observations, model simulation outputs, and in situ datasets, we track the pathway of this intrusion into the extensive shallow areas and coral reef complexes along the basin's shores. We also provide statistical evidence that the subsurface intrusion plays a key role in the development of the southern Red Sea phytoplankton blooms.

In his hours of relaxation, it is interesting for the physician occasionally to wander into the philosophical byways which offer opportunities for quiet reflection on medicine as a whole: its ends and aims, its pitfalls and dangers, its methods and standards and its accomplishments. In this vein it seems desirable to consider the trend of morbidity in childhood, particularly with a view to evaluating the results of efforts for prevention and the lines along which future effort should be directed. The first logical step requires a familiarity with pediatrics of the past and with the causes of its morbidity and mortality. Most pediatricians have dipped lightly into the pools of ancient knowledge, and all are familiar with the reputation credited to the authors of old of being past-masters in the observation and recording of clinical phenomena. In individual instances, this reputation is warranted, but in general, the outstanding and inevitable

In 1934 DeLange1reported a syndrome, occurring in infants, characterized by congenital muscular hypertrophy, extrapyramidal disturbances and mental deficiency. She described three cases which had come directly under her observation and cited one case which had been reported nearly a half-century before by Bruck.2With the possible exception of one other case, which will be referred to later (Schiff and Balint3), these four cases are the only instances of this syndrome which we have found reported in the literature. We are presenting an additional case, with certain studies on the metabolism of the patient. REPORT OF CASE History.—A Negro boy was delivered at the Philadelphia General Hospital spontaneously and without injury at term in July 1933. The mother, a low grade moron, was only 14 years of age. The father of the patient was also the father of the child's mother. The weight of the child

The purpose of the study to be reported was to determine the value of percomorph liver oil 1 as the sole antirachitic agent in healthy young infants, ultimate reliance being placed on roentgenologic rather than clinical criteria for detecting rickets. There has been considerable confusion concerning adequate prophylactic dosage of vitamin D, especially of the concentrates, such as viosterol. Studies in which unassayed vitamin D products and clinical rather than roentgenologic data have been used have clouded the issue. Shelling and Hopper 2 have pointed out the inadequacies of the early studies in which cod liver oil and viosterol were used in the prevention of rickets. There has been much controversy over the relative efficacy, unit for unit, of natural and irradiated products containing vitamin D. Recently Shelling and Hopper 2 maintained that cod liver oil and viosterol are of equal antirachitic potency in relation to the number of units

Next to treatment, prognosis most intimately concerns the patient; and yet, of all the subdivisions of medical study, prognosis lends itself least to scientific precision. In the case of tuberculosis, one of the chief reasons for this is the lack of sufficiently numerous data, gathered after observation sufficiently prolonged. When the active stage has been estimated as lasting from five to twenty years on the average, it is not hard to explain the deficiencies. The general practitioner, who may follow patients from birth to death even in the third and fourth decades, has material at hand for valuable observations but usually lacks time or inclination to put them on record. For some years, certain general conclusions as to the prognosis of tuberculosis in early life have received wide acceptance. These may be epitomized from an article by Nassau and Zweig. 1 When infection occurs in the first three months of

To the Editor:— InThe JournalJanuary 21, page 261, appears a letter from Dr. J. G. Downing of Boston with a note of warning against the use of ammoniated mercury in the treatment of impetigo in the newborn and of its possible effect of causing diarrhea. Without attempting to discuss the latter factor, I should like to suggest the use of a 1 or 2 per cent alcoholic solution of gentian violet in the treatment of impetigo. Some fifteen years ago it occurred to my associates and me that any gram-positive organism should be killed by the use of gentian violet. It was also found that the Sacharomyces albicans causing thrush was gram positive. For use in the mouth we employed a 1 or 2 per cent aqueous solution of gentian violet. Since adopting these procedures we have had practically no difficulty in curing either thrush or impetigo with