Monitoring land degradation in southern Tunisia: A test of LANDSAT imagery and digital data

The possible use of LANDSAT imagery and digital data for monitoring desertification indicators in Tunisia was studied. Field data were sampled in Tunisia for estimation of mapping accuracy in maps generated through interpretation of LANDSAT false color composites and processing of LANDSAT computer compatible tapes respectively. Temporal change studies were carried out through geometric registration of computer classified windows from 1972 to classified data from 1979. Indications on land degradation were noted in some areas. No important differences, concerning results, between the interpretation approach and the computer processing approach were found

The use of LANDSAT-1 imagery for water quality studies in southern Scandinavia

The possibilities of using LANDSAT-1 images for environmental studies, with special references to water quality studies, were investigated by selecting test areas in southern Scandinavia. The MSS images of different bands are compared under the magnification of an Interpretoscope and densitometric analyses are performed in a Schnell-photometer. The possibility of tracing pollution plumes is studied in the Oresund outside Copenhagen. The effect of different sewers and the circulation of the polluted water is analyzed in various situations. The variation in reflectivity of a great number of lakes in South and Middle Sweden is studied by means of densitometric analyses and significant regional differences are found. The correlation with in situ measurements of water quality (turbidity and secchi disc transparency) of the sampled lakes (made by the National Swedish Environment Protection Board) is fairly good

Assessing Land Degradation/Recovery in the African Sahel from Long-Term Earth Observation Based Primary Productivity and Precipitation Relationships

The ‘rain use efficiency’ (RUE) may be defined as the ratio of above-ground net primary productivity (ANPP) to annual precipitation, and it is claimed to be a conservative property of the vegetation cover in drylands, if the vegetation cover is not subject to non-precipitation related land degradation. Consequently, RUE may be regarded as means of normalizing ANPP for the impact of annual precipitation, and as an indicator of non-precipitation related land degradation. Large scale and long term identification and monitoring of land degradation in drylands, such as the Sahel, can only be achieved by use of Earth Observation (EO) data. This paper demonstrates that the use of the standard EO-based proxy for ANPP, summed normalized difference vegetation index (NDVI) (National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies 3rd generation (GIMMS3g)) over the year (ΣNDVI), and the blended EO/rain gauge based data-set for annual precipitation (Climate Prediction Center Merged Analysis of Precipitation, CMAP) results in RUE-estimates which are highly correlated with precipitation, rendering RUE useless as a means of normalizing for the impact of annual precipitation on ANPP. By replacing ΣNDVI by a ‘small NDVI integral’, covering only the rainy season and counting only the increase of NDVI relative to some reference level, this problem is solved. Using this approach, RUE is calculated for the period 1982–2010. The result is that positive RUE-trends dominate in most of the Sahel, indicating that non-precipitation related land degradation is not a widespread phenomenon. Furthermore, it is argued that two preconditions need to be fulfilled in order to obtain meaningful results from the RUE temporal trend analysis: First, there must be a significant positive linear correlation between annual precipitation and the ANPP proxy applied. Second, there must be a near-zero correlation between RUE and annual precipitation. Thirty-seven percent of the pixels in Sahel satisfy these requirements and the paper points to a range of different reasons why this may be the case

Biomass Productivity-Based Mapping of Global Land Degradation Hotspots

Land degradation is a global problem affecting negatively the livelihoods and food security of billions of people, especially farmers and pastoralists in the developing countries. Eradicating extreme poverty without adequately addressing land degradation is highly unlikely. Given the importance and magnitude of the problem, there have been recurring efforts by the international community to identify the extent and severity of land degradation in global scale. As discussed in this paper, many previous studies were challenged by lack of appropriate data or shortcomings of their methodological approaches. In this paper, using global level remotely sensed vegetation index data, we identify the hotspots of land degradation in the world across major land cover types. In doing so, we use the long-term trend of inter-annual vegetation index as an indicator of biomass production decline or improvement. Besides the elimination of technical factors, confounding the relationship between the indicator and the biomass production of the land, we apply a methodology which accounts for masking effects of both inter-annual rainfall variation and atmospheric fertilization. We also delineate the areas where chemical fertilization could be hiding the inherent land degradation processes. Our findings show that land degradation hotpots cover about 29% of global land area and are happening in all agro-ecologies and land cover types. Land degradation is especially massive in grasslands. About 3.2 billion people reside in these degrading areas. However, the number of people affected by land degradation is likely to be higher as more people depend on the continuous flow of ecosystem goods and services from these affected areas. As we note in the paper, this figure, although, does not include all possible areas with degraded lands, it identifies those areas where land degradation is most acute and requires priority actions in both in-depth research and management measures to combat land degradation. Our findings indicate that, in fact, land improvement has also occurred in about 2.7% of global land area during the last three decades, providing a support that with appropriate actions land degradation trend could be reversed, and that the efforts to address land degradation need to be substantially increased, at least by a factor, to attain the vision of Zero Net Land Degradation. We also identify concrete aspects in which these results should be interpreted with caution, the limitations of this work and the key areas for future research

Assessing Land Degradation and Desertification Using Vegetation Index Data: Current Frameworks and Future Directions

Land degradation and desertification has been ranked as a major environmental and social issue for the coming decades. Thus, the observation and early detection of degradation is a primary objective for a number of scientific and policy organisations, with remote sensing methods being a candidate choice for the development of monitoring systems. This paper reviews the statistical and ecological frameworks of assessing land degradation and desertification using vegetation index data. The development of multi-temporal analysis as a desertification assessment technique is reviewed, with a focus on how current practice has been shaped by controversy and dispute within the literature. The statistical techniques commonly employed are examined from both a statistical as well as ecological point of view, and recommendations are made for future research directions. The scientific requirements for degradation and desertification monitoring systems identified here are: (I) the validation of methodologies in a robust and comparable manner; and (II) the detection of degradation at minor intensities and magnitudes. It is also established that the multi-temporal analysis of vegetation index data can provide a sophisticated measure of ecosystem health and variation, and that, over the last 30 years, considerable progress has been made in the respective research

Injectable local anaesthetic agents for dental anaesthesia

Background: Pain during dental treatment, which is a common fear of patients, can be controlled successfully by local anaesthetic. Several different local anaesthetic formulations and techniques are available to dentists. / Objectives: Our primary objectives were to compare the success of anaesthesia, the speed of onset and duration of anaesthesia, and systemic and local adverse effects amongst different local anaesthetic formulations for dental anaesthesia. We define success of anaesthesia as absence of pain during a dental procedure, or a negative response to electric pulp testing or other simulated scenario tests. We define dental anaesthesia as anaesthesia given at the time of any dental intervention. Our secondary objective was to report on patients' experience of the procedures carried out. / Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library; 2018, Issue 1), MEDLINE (OVID SP), Embase, CINAHL PLUS, WEB OF SCIENCE, and other resources up to 31 January 2018. Other resources included trial registries, handsearched journals, conference proceedings, bibliographies/reference lists, and unpublished research. / Selection criteria: We included randomized controlled trials (RCTs) testing different formulations of local anaesthetic used for clinical procedures or simulated scenarios. Studies could apply a parallel or cross‐over design. / Data collection and analysis: We used standard Cochrane methodological approaches for data collection and analysis. / Main results: We included 123 studies (19,223 participants) in the review. We pooled data from 68 studies (6615 participants) for meta‐analysis, yielding 23 comparisons of local anaesthetic and 57 outcomes with 14 different formulations. Only 10 outcomes from eight comparisons involved clinical testing. We assessed the included studies as having low risk of bias in most domains. Seventy‐three studies had at least one domain with unclear risk of bias. Fifteen studies had at least one domain with high risk of bias due to inadequate sequence generation, allocation concealment, masking of local anaesthetic cartridges for administrators or outcome assessors, or participant dropout or exclusion. We reported results for the eight most important comparisons. / Success of anaesthesia: When the success of anaesthesia in posterior teeth with irreversible pulpitis requiring root canal treatment is tested, 4% articaine, 1:100,000 epinephrine, may be superior to 2% lidocaine, 1:100,000 epinephrine (31% with 2% lidocaine vs 49% with 4% articaine; risk ratio (RR) 1.60, 95% confidence interval (CI) 1.10 to 2.32; 4 parallel studies; 203 participants; low‐quality evidence). When the success of anaesthesia for teeth/dental tissues requiring surgical procedures and surgical procedures/periodontal treatment, respectively, was tested, 3% prilocaine, 0.03 IU felypressin (66% with 3% prilocaine vs 76% with 2% lidocaine; RR 0.86, 95% CI 0.79 to 0.95; 2 parallel studies; 907 participants; moderate‐quality evidence), and 4% prilocaine plain (71% with 4% prilocaine vs 83% with 2% lidocaine; RR 0.86, 95% CI 0.75 to 0.99; 2 parallel studies; 228 participants; low‐quality evidence) were inferior to 2% lidocaine, 1:100,000 epinephrine. Comparative effects of 4% articaine, 1:100,000 epinephrine and 4% articaine, 1:200,000 epinephrine on success of anaesthesia for teeth/dental tissues requiring surgical procedures are uncertain (RR 0.85, 95% CI 0.71 to 1.02; 3 parallel studies; 930 participants; very low‐quality evidence). Comparative effects of 0.5% bupivacaine, 1:200,000 epinephrine and both 4% articaine, 1:200,000 epinephrine (odds ratio (OR) 0.87, 95% CI 0.27 to 2.83; 2 cross‐over studies; 37 participants; low‐quality evidence) and 2% lidocaine, 1:100,000 epinephrine (OR 0.58, 95% CI 0.07 to 5.12; 2 cross‐over studies; 31 participants; low‐quality evidence) on success of anaesthesia for teeth requiring extraction are uncertain. Comparative effects of 2% mepivacaine, 1:100,000 epinephrine and both 4% articaine, 1:100,000 epinephrine (OR 3.82, 95% CI 0.61 to 23.82; 1 parallel and 1 cross‐over study; 110 participants; low‐quality evidence) and 2% lidocaine, 1:100,000 epinephrine (RR 1.16, 95% CI 0.25 to 5.45; 2 parallel studies; 68 participants; low‐quality evidence) on success of anaesthesia for teeth requiring extraction and teeth with irreversible pulpitis requiring endodontic access and instrumentation, respectively, are uncertain. For remaining outcomes, assessing success of dental local anaesthesia via meta‐analyses was not possible. / Onset and duration of anaesthesia: For comparisons assessing onset and duration, no clinical studies met our outcome definitions. Adverse effects (continuous pain measured on 170‐mm Heft‐Parker visual analogue scale (VAS)) Differences in post‐injection pain between 4% articaine, 1:100,000 epinephrine and 2% lidocaine, 1:100,000 epinephrine are small, as measured on a VAS (mean difference (MD) 4.74 mm, 95% CI ‐1.98 to 11.46 mm; 3 cross‐over studies; 314 interventions; moderate‐quality evidence). Lidocaine probably resulted in slightly less post‐injection pain than articaine (MD 6.41 mm, 95% CI 1.01 to 11.80 mm; 3 cross‐over studies; 309 interventions; moderate‐quality evidence) on the same VAS. For remaining comparisons assessing local and systemic adverse effects, meta‐analyses were not possible. Other adverse effects were rare and minor. / Patients' experience: Patients' experience of procedures was not assessed owing to lack of data. / Authors' conclusions: For success (absence of pain), low‐quality evidence suggests that 4% articaine, 1:100,000 epinephrine was superior to 2% lidocaine, 1:100,000 epinephrine for root treating of posterior teeth with irreversible pulpitis, and 2% lidocaine, 1:100,000 epinephrine was superior to 4% prilocaine plain when surgical procedures/periodontal treatment was provided. Moderate‐quality evidence shows that 2% lidocaine, 1:100,000 epinephrine was superior to 3% prilocaine, 0.03 IU felypressin when surgical procedures were performed. Adverse events were rare. Moderate‐quality evidence shows no difference in pain on injection when 4% articaine, 1:100,000 epinephrine and 2% lidocaine, 1:100,000 epinephrine were compared, although lidocaine resulted in slightly less pain following injection. Many outcomes tested our primary objectives in simulated scenarios, although clinical alternatives may not be possible. Further studies are needed to increase the strength of the evidence. These studies should be clearly reported, have low risk of bias with adequate sample size, and provide data in a format that will allow meta‐analysis. Once assessed, results of the 34 ‘Studies awaiting classification (full text unavailable)’ may alter the conclusions of the review