Characterization of the Nigerian Shoreline using Publicly-Available Satellite Imagery

Current methods of shoreline mapping include aerial and high-resolution satellite imagery and ground-based surveying, all of which require considerable investment of human and material resources. Mapping and continuous updating of the shoreline for developing countries, such as Nigeria, is a challenge. Most of the information on the Nigerian shoreline is based on ‘surveys of opportunity’ performed by various government agencies over a wide time span. Additional surveys conducted by the multi-national oil and gas companies exploring in the region are typically not available for use by government agencies. In cases where the data are available, the variety in methods used for shoreline mapping can result in inconsistencies

Beyond the Chart: The use of Satellite Remote Sensing for Assessing the Adequacy and Completeness Information

Chart adequacy and completeness information consists of the symbols, abbreviations and warnings used to inform mariners of the level of confidence that should be given to data on a nautical chart. This information is derived both from the nautical chart and sailing directions. However, analysis based solely on these datasets is limited without access to the sources (e.g., smooth sheets). Publically-available, multi-spectral satellite imagery and published algorithms can be used to derive estimates of the relative bathymetry in shallow, clear waters. In this study, we evaluate the potential of these methods for supplementing the procedure to assess the adequacy of hydrographic surveying and nautical charting coverage. Optically-derived bathymetry provides information in areas that have not been surveyed and monitor any seafloor changes that may have occurred since the last survey of the area. Preliminary results show that multi-spectral satellite remote sensing is also potentially beneficial as a reconnaissance tool prior to a hydrographic acoustic survey

Spectral characterization of the Nigerian shoreline using Landsat imagery

The challenges of shoreline mapping include the high costs of acquiring up-to-date survey data over the coastal area. As a result, in many developing countries, the shoreline has not been consistently mapped. The variety of methods used for this mapping and the large time differences between the surveys (on the order of decades) could result in inaccuracies in shoreline data. This study presents the development of a shoreline characterization procedure for the Nigerian coastline using satellite remote sensing technology. The study goal is to produce a complete, consistent and continuous shoreline map using publicly available data processed in a GIS environment. A spectral analysis using different satellite bands was conducted to define the land/water boundary and characterize the coastal area around the shoreline. The satellite-derived shorelines were compared to charted shorelines for adequacy and consistency. The procedure was developed based on study sites along the Nigerian coastline. Although the shoreline characterization procedure is developed based on datasets from Nigeria, the procedure should be suitable for use in mapping other developing areas around world

Development of a Geo-spatial Analysis Methodology for Assessing the Adequacy of Hydrographic Surveying and Nautical Charts

IHO Publication C-55 (Status of Hydrographic Surveying and Nautical Charting Worldwide) contains information about the progress of hydrographic surveying and nautical charting for a country with navigable waters under its jurisdiction. Listed primarily as percent coverage, it is difficult to use this information to determine: 1) if the current level of surveying or charting is adequate or in need of action, or 2) can be used to compare different locations. An analysis and assessment methodology has been developed to assess the adequacy hydrographic surveying and nautical charting coverage. Indications of chart adequacy and completeness as depicted on current charts or sailing directions are spatially correlated with significant maritime sites/areas associated with social, environmental and economic factors. The procedure was developed in a GIS environment for Belize and Nigeria. Areas within the charts were prioritized based on zone of confidence, source diagrams, chart quality symbols/indicators, doubtful danger markings, survey completeness, navigationally-significant depths, and areas of significant maritime importance

Future directions in hydrography using satellite-derived bathymetry

Satellite remote sensing provides useful reconnaissance tool for mapping near-shore bathymetry, characterizing a coastal area and monitoring any seafloor changes that may have occurred since the last hydrographic survey of the area. At the 2012 Canada Hydro conference, a study was presented on the potential use of Landsat satellite imagery to map shallow-water bathymetry in a GIS environment over three study sites. Since then, several collaborations between the current study group and various hydrographic organizations were established with the goal of implementing optically-derived bathymetry as part of their data acquiring procedure. Bathymetry over additional study sites around the world was tested. Also, different commercial software packages were evaluated to provide an affordable processing platform for hydrographic offices in developing countries. In this paper, an overview will be provided on the advances that have been achieved in the past year and an update and future directions of the study

Selecting Forecasting Methods

I examined six ways of selecting forecasting methods: Convenience, “what’s easy,” is inexpensive, but risky. Market popularity, “what others do,” sounds appealing but is unlikely to be of value because popularity and success may not be related and because it overlooks some methods. Structured judgment, “what experts advise,” which is to rate methods against prespecified criteria, is promising. Statistical criteria, “what should work,” are widely used and valuable, but risky if applied narrowly. Relative track records, “what has worked in this situation,” are expensive because they depend on conducting evaluation studies. Guidelines from prior research, “what works in this type of situation,” relies on published research and offers a low-cost, effective approach to selection. Using a systematic review of prior research, I developed a flow chart to guide forecasters in selecting among ten forecasting methods. Some key findings: Given enough data, quantitative methods are more accurate than judgmental methods. When large changes are expected, causal methods are more accurate than naive methods. Simple methods are preferable to complex methods; they are easier to understand, less expensive, and seldom less accurate. To select a judgmental method, determine whether there are large changes, frequent forecasts, conflicts among decision makers, and policy considerations. To select a quantitative method, consider the level of knowledge about relationships, the amount of change involved, the type of data, the need for policy analysis, and the extent of domain knowledge. When selection is difficult, combine forecasts from different methods

Protein carbonylation and aggregation precede neuronal apoptosis induced by partial glutathione depletion

While the build-up of oxidized proteins within cells is believed to be toxic, there is currently no evidence linking protein carbonylation and cell death. In the present study, we show that incubation of nPC12 (neuron-like PC12) cells with 50 μM DEM (diethyl maleate) leads to a partial and transient depletion of glutathione (GSH). Concomitant with GSH disappearance there is increased accumulation of PCOs (protein carbonyls) and cell death (both by necrosis and apoptosis). Immunocytochemical studies also revealed a temporal/spatial relationship between carbonylation and cellular apoptosis. In addition, the extent of all three, PCO accumulation, protein aggregation and cell death, augments if oxidized proteins are not removed by proteasomal degradation. Furthermore, the effectiveness of the carbonyl scavengers hydralazine, histidine hydrazide and methoxylamine at preventing cell death identifies PCOs as the toxic species. Experiments using well-characterized apoptosis inhibitors place protein carbonylation downstream of the mitochondrial transition pore opening and upstream of caspase activation. While the study focused mostly on nPC12 cells, experiments in primary neuronal cultures yielded the same results. The findings are also not restricted to DEM-induced cell death, since a similar relationship between carbonylation and apoptosis was found in staurosporine- and buthionine sulfoximine-treated nPC12 cells. In sum, the above results show for the first time a causal relationship between carbonylation, protein aggregation and apoptosis of neurons undergoing oxidative damage. To the best of our knowledge, this is the first study to place direct (oxidative) protein carbonylation within the apoptotic pathway

Confronting and mitigating the risk of COVID-19 associated pulmonary aspergillosis.

Cases of COVID-19 associated pulmonary aspergillosis (CAPA) are being increasingly reported and physicians treating patients with COVID-19-related lung disease need to actively consider these fungal co-infections. The SARS-CoV-2 (COVID-19) virus causes a wide spectrum of disease in healthy individuals as well as those with common comorbidities [1]. Severe COVID-19 is characterised acute respiratory distress syndrome (ARDS) secondary to viral pneumonitis, treatment of which may require mechanical ventilation or extracorporeal membrane oxygenation (ECMO) [2]. Clinicians are alert to the possibility of bacterial co-infection as a complication of lower respiratory tract viral infection; for example a recent review found that 72% of patients with COVID-19 received antimicrobial therapy [3]. However, the risk of fungal co-infection, in particular COVID-19 associated pulmonary aspergillosis (CAPA), remains underappreciated. Fungal disease consistent with invasive aspergillosis (IA) has been observed with other severe Coronaviruses such as Severe Acute Respiratory Syndrome (SARS-CoV-2003) [4, 5] and Middle East Respiratory Syndrome (MERS-CoV) [6]. From the outset of the COVID-19 pandemic, there were warning signs of secondary invasive fungal infection; Aspergillus flavus was isolated from the respiratory tract from one of 99 patients in the first COVID-19 cohort from Wuhan to be reported in any detail [2] and Aspergillus spp. were isolated from 2/52 (3.8%) of a subsequent cohort of critically unwell patients from this region [7]. More recently, retrospective case series from Belgium [8], France [9], The Netherlands [10] and Germany [11] have reported evidence of CAPA in an alarming 20–35% of mechanically ventilated patients