Automatic plant pest detection and recognition using k-means clustering algorithm and correspondence filters

Plant pest recognition and detection is vital for food security, quality of life and a stable agricultural economy. This research demonstrates the combination of the k-means clustering algorithm and the correspondence filter to achieve pest detection and recognition. The detection of the dataset is achieved by partitioning the data space into Voronoi cells, which tends to find clusters of comparable spatial extents, thereby separating the objects (pests) from the background (pest habitat). The detection is established by extracting the variant distinctive attributes between the pest and its habitat (leaf, stem) and using the correspondence filter to identify the plant pests to obtain correlation peak values for different datasets. This work further establishes that the recognition probability from the pest image is directly proportional to the height of the output signal and inversely proportional to the viewing angles, which further confirmed that the recognition of plant pests is a function of their position and viewing angle. It is encouraging to note that the correspondence filter can achieve rotational invariance of pests up to angles of 360 degrees, which proves the effectiveness of the algorithm for the detection and recognition of plant pests

Cor triatriatum sinistrium in a 10 year old Nigerian: A case report

We present a rare and first case of Cor triatriatum sinistrum (CT) in a patient who presents with dyspnoea, easy fatigability, chest pain, murmurs and typical ECG and 2D-echo findings. The purpose of presenting this casereport is to highlight the distinctive manifestation of Cor triatriatumsinistrum and to provide a concise report of this disease with the hopethat such information will help identify patients earlier in the course of their disease. Surgical correction offers good and long term results for both classicand atypical types. In a resource poor country like ours, high index of suspicion, early diagnosis and timely referral are warranted so as to avert death

Mercury presence and speciation in the South Atlantic Ocean along the 40°S transect

Mercury (Hg) natural biogeochemical cycle is complex and a significant portion of biological and chemical transformation occurs in the marine environment. To better understand the presence and abundance of Hg species in the remote ocean regions, waters of South Atlantic Ocean along 40°S parallel were investigated during UK-GEOTRACES cruise GA10. Total mercury (THg), methylated mercury (MeHg), and dissolved gaseous mercury (DGM) concentrations were determined. The concentrations were very low in the range of pg/L (femtomolar). All Hg species had higher concentration in western than in eastern basin. THg did not appear to be a useful geotracer. Elevated methylated Hg species were commonly associated with low-oxygen water masses and occasionally with peaks of chlorophyll a, both involved with carbon (re)cycling. The overall highest MeHg concentrations were observed in themixed layer (500m) and in the vicinity of the Gough Island. Conversely, DGM concentrations showed distinct layering and differed between the water masses in a nutrient-like manner. DGM was lowest at surface, indicating degassing to the atmosphere, and was highest in the Upper Circumpolar Deep Water, where the oxygen concentration was lowest. DGM increased also in Antarctic Bottom Water. At one station, dimethylmercury was determined and showed increase in region with lowest oxygen saturation. Altogether, our data indicate that the South Atlantic Ocean could be a source of Hg to the atmosphere and that its biogeochemical transformations depend primarily upon carbon cycling and are thereby additionally prone to global ocean change

Chinawa JM Cor triatriatum sinistrium in a 10 year old Nigerian: A case report

Abstract We present a rare and first case of Cor triatriatum sinistrum (CT) in a patient who presents with dyspnoea, easy fatigability, chest pain, murmurs and typical ECG and 2D-echo findings. The purpose of presenting this case report is to highlight the distinctive manifestation of Cor triatriatum sinistrum and to provide a concise report of this disease with the hope that such information will help identify patients earlier in the course of their disease. Surgical correction offers good and long term results for both classic and atypical types. In a resource poor country like ours, high index of suspicion, early diagnosis and timely referral are warranted so as to avert death

Ice wedge polygon development on different temporal and spatial scales in the northern Yukon, Canada

Ice wedge polygons (IWP) are amongst the most typical permafrost phenomena in Arctic lowlands. Within the northern hemisphere, IWP are thought to occupy between 250,000 km² (Minke et al., 2007) and 2,600,000 km² (Mackay 1972) of the tundra and boreal forest, which accounts for 3 to 31% of the arctic land mass including glaciated regions. Besides the wide spatial distribution, IWP have stored large quantities of organic carbon and nitrogen on geological timescales and are therefore regarded as greenhouse gas sinks. Continuous organic matter accumulation and preservation due to syngenetic permafrost aggradation make arctic polygon mires an excellent climate and environmental archive. Here we present the results of a multidisciplinary palaeoenvironmental study on IWP in the northern Yukon, Canada. High-resolution laboratory analyses were carried on a permafrost core together with the overlying active layer (233 cm length) which was drilled in 2012. Based on 14 AMS radiocarbon dates spanning the last 5,000 years, we report high-resolution ground ice stratigraphy, stable water isotopes (δ18O, δD), sedimentary data including grain size distribution and biogeochemical parameters (OC, N, C/N ratio, δ13C), as well as pollen and diatom assemblages. This is accompanied by high-resolution remote sensing data based on airborne LIDAR and on underground investigations using electrical resistivity tomography in different resolutions. The studied low-centered IWP indicates that the whole IWP field was established after a shallow lake had drained at about 3200 cal BP. The diatom assemblage in the lower part of the sedimentary record is dominated by planktonic and pioneer species and by those preferring alkaline conditions. Ice-wedge cracking in water-saturated sediments started immediately after lake drainage and led to the formation of a polygon mire. Downward closed-system freezing of the talik is indicated by continuously decreasing δ18O (δD) values, a δ18O/δD-regression-slope below the Global Meteoric Water Line and a negative relationship between δD and D excess. On the one hand, pollen assemblages in lake sediments have captured a regional signal of vegetation composition and climate. On the other hand, we assume that after lake drainage the pollen record represents a very local signal as it is dominated by the local plant communities growing in the IWP. Therefore, we suggest that the ability to infer regional climate information on temperature and precipitation is good for lake sediments but weak for the overlying peat record. This is indicated by a sudden dominance of Cyperaceae pollen after the transition from lake sediments into terrestrial peat of the IWP. Other IWP along the mainland coast of the Yukon suggest a high temporal diversity in polygon mire origin and behavior. IWP beyond the late Wisconsin glacial limit are mostly high-centered with strong signs of degradation. Coastal cliff exposures with deeply thawed ice wedge surfaces and secondary or even tertiary IW generations support this view. Ice wedge casts dating back until 8,400 cal BP (Fritz et al., 2012) indicate previous periods of ice wedge degradation and meltout. Intermediate forms of IWP (neither low-centered nor high-centered) dominate the mainland coast of the Yukon on the rolling ground moraines. Glacial outwash plains at the former glacial border host mostly low-centered IWP. On Herschel Island, we find many generations of IW and corresponding sedimentary records in the centers although IWP are not as frequent on the high-relief endmoraine, which is Herschel Island, than on the relatively flat mainland coast of the Yukon. Holocene IWP have mostly a surficial expression whereas the older late Wisconsin/Pleistocene/glacial IWP are often buried under a 0.7 to 1.5 m thick sediment cover. Higher than modern summer air temperatures, presumable during the Holocene thermal maximum, caused deeper thaw and led to a truncation of late Wisconsin/Pleistocene/glacial IW. This suggests that remote-sensing based estimations of arctic-wide IWP coverage will give conservative numbers as buried IWP systems will remain invisible. References Fritz, M., Wetterich, S., Schirrmeister, L., Meyer, H., Lantuit, H., Preusser, F., Pollard, W.H., 2012. Eastern Beringia and beyond: Late Wisconsinan and Holocene landscape dynamics along the Yukon Coastal Plain, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 319–320, 28-45. doi:10.1016/j.palaeo.2011.12.015. Mackay, J.R., 1972. The world of underground ice. Annals of the Association of American Geographers 62, 1-22. Minke, M., Donner, N., Karpov, N.S., de Klerk, P., Joosten, H. (2007). Distribution, diversity, development and dynamics of polygon mires: examples from Northeast Yakutia (Siberia), Peatlands International 1/2007, 36-40