Introducing an effect of climate change into globals models of rain fade on telecommunications links

Rain attenuation limits the performance of microwave telecommunication links functioning above approximately 5 GHz. Recent studies have revealed that over the last twenty years the occurrence of rain, at intensities that cause outage on terrestrial links, has experienced a strongly increasing trend in the UK. Globally, the height of rain events has also been observed to increase, which may compound increasing trends in rain fade experienced by Earth-Space communication systems. These climatic changes are almost certainly having significant effect on the performance of existing radio systems, and need to be taken into consideration when planning future systems. The International Telecommunication Union – Radio Section (ITU-R), maintains a set of internationally accepted models for the engineering and regulation of radio systems globally. Although under constant revision, these models assume that atmospheric fading is stationary. This assumption is inherent in the way models are tested.In this project, a method is developed to estimate global trends in one of the most fundamental parameters to the ITU-R models: the one-minute rain rate exceeded for 0.01% of an average year. This method introduces climate change into the ITU-R model of this parameter: Rec. ITU-R P.837. The new model is tested using a method that does not make a stationary climate assumption. Salonen-Poiares Baptista distribution, which is the fundamental method for developing ITU-R Rec. P.837 has been tested using UK Environment Agency data, but no correlations was found between measured annual accumulations and distribution parameters. Nonetheless a link was found between mean annual total precipitations (MT) and rain exceeded at larger time percentages such as; 0.1% and 1%

Impact Damage Tolerance of Composite Laminates with Through-The-Thickness Stitches

The ability of through-the-thickness stitches to contain damage during a low-velocity impact event and increase the residual strength of stitched panels was investigated in this research. The impact response, spread of interlaminar delaminations, dent depth, surface damage, and static residual strength after impact were studied for carbon-epoxy specimens fabricated from HTS40 TohoTenax standard modulus fibers, stitched together with Vectran 1200 denier thread and infused with API 1078 resin after through-the-thickness stitching. Three different stitch patterns were used to explore the ability to arrest impact damage during and after impact. Simply supported boundary conditions were maintained during the impact testing. Non-destructive evaluations were performed using ultrasonic C-scans and X-ray computed tomography (CT) imaging to determine the shape, size, and location of delaminations. Results indicate that while the dynamic response during the impact event was almost the same for the unstitched specimens and all stitch patterns considered, the extent of delamination and the compression strength after impact varied greatly. For both the 60 J and 80 J impact energies, the delamination area was significantly less for the stitched specimens than for the unstitched specimens, but the range of delamination areas among the stitch patterns was much larger for the lower impact energy than for the greater impact energy. Similarly, while the presence of stitching influenced the compression after impact strength, the strength values for all stitch patterns were very similar. These results are a step toward quantifying the influence of through-the-thickness stitching

Synthesis, Characterization, and Evaluation of Small Molecule-based Fluorogenic Probes for the Detection of Cellular Thiols

Fluorescence methods for disease diagnosis and detection of important analytes are becoming popular route as a technique, as they offer a simple non-invasive approach. Recently, many novel fluorophores and probes have been reported for selectively and sensitively detecting low abundance biological species in disease pathways. Biological thiols, such as glutathione, cysteine, and homocysteine, along with the smallest member hydrogen sulfide, are key thiol analytes in biological environments, and they play a vital role in living systems by maintaining the redox homeostasis of cells. Alteration of their ratios can cause cellular dysfunction and cell death. Furthermore, thiol levels in cells and biological fluids act as biomarkers of several diseases, including neurodegenerative disorders, liver disease, cystic fibrosis, pulmonary and cardiovascular diseases, and Alzheimer’s disease. Thus, the development of efficacious methods for detection and quantification of biological thiols has received significant attention in recent years. Although many traditional thiol detection methods are available, fluorescent methods hold more promise for simple, non-invasive detection with simple instrumentation. The work presented in this dissertation discusses the successful fluorescent detection of biologically important thiols with two probes HMBQ-Nap 1 and DCM-Cys. The HMBQ-Nap 1 probe consists of a hydroxymethyl benzoquinone trigger group (HMBQ) and 4-amino-9-(n-butyl)-1,8-naphthalimide (Nap 2) as the reporter dye. This probe led to excellent class selective detection of the free thiols glutathione, cysteine, and homocysteine versus other analytes found in the body. The second probe, DCM-Cys, is composed of a cysteine-selective acrylate moiety attached to dicyanomethylene-4H-pyran (DCM) reporter dye via a benzyl alcohol linker. DCM-Cys exhibited a remarkable ability to detect free cysteine in media versus other thiols and various potent analytes found in biological environments. Both HMBQ-Nap 1 and DCM-Cys offer nM in vitro detection, and successful in cyto imaging of thiols. Selectivity, a relative low limit of detection (nM), the ability to function under physiological conditions and a high signal-to-background ratio of these methods as well as low thiol-to-probe ratios for the qualitative and quantitative detection, and relatively short response time make these probes excellent systems for thiol analysis

Evidence of Microplastic Contamination in Surface Waters and Sediment of Kelani River Estuary

The presence of microplastics poses a significant threat to the marine environment. Amidst the issue has a global concern, there are very limited studies conducted in Sri Lanka. Therefore, the present study attempts to study the presence of microplastics in the Kelani River estuary from the head waters to the river mouth samples were collected from nine locations within the estuary including both river banks and mid rivers and also from the coastal waters. Sampling was conducted between February 2018 to November 2018 considering the both dry and wet period of the year. Water samples were collected using 200 μm plankton net and organic matter was removed with 10% KOH. Digested water samples were filtered through 1.2 μm GF/C filter paper. Density separation was used to separate microplastics from and sediment. Saturated NaCl was mixed with sediment and kept for several hours to separate. Low density upper layer was collected with filter paper. Microplastics were enumerated and categorised according to shape and color with the aid of a stereomicroscope. Polymer types of microplastics were determined by analysing the FTIR spectrum. Microplastics were more abundant in surface water (7±0.28 to 2.5±1.323 items/m3) compared to sediment samples (4±0.5 to 1±0.43 item/kg). Plastic fibers (36%) recorded significantly high numbers and transparent color (29%) was the dominant among the samples. Polyethylene, Polyethylene terephthalate, Polypropylene, Polystyrene, and Polyamide were the polymer types that were detected in ATR-FTIR spectroscopy. Majority of microplastics showed a secondary origin from the breakdown of large plastic items.Keywords: Microplastics, Surface water, Sediment, Kelani river estuar

Biofouling Community Assemblage in Coastal Waters Adjacent to Port of Colombo, West Coast of Sri Lanka

Port of Colombo which controls majority of country's foreign cargo has been the major trading canter of the country for decades. Although, the port has been subjected to Port biological baseline surveys for non-indigenous species, adjacent coastal waters have obtained limited attention. Hence present study was conducted in three sampling locations; Dikkowita Fisheries Harbour, Kirulapone canal opening, Panadura Fisheries Harbour along the coastal waters adjacent to Port of Colombo. Panadura Fisheries Harbour was taken as the reference point due to its distance from Colombo Port and relatively low international shipping activities. Combination of environmental surveys with photo quadrant sampling, and submerged structure sampling was conducted to detect fouling and associated organisms. A modified version of survey procedure and protocol developed by Marine Biological Association of United Kingdom was followed for the study. Convenience sampling method was used to select sampling points where four replicates of quadrants were randomly placed within 12 m long belt transect. Coral Point Count with Excel Extension version 4.1 software was used to quantify the abundance of the species by estimating the percentage cover and the individual count from each photo quadrant. Environmental surveys were carried out once in two months’ intervals along the inter-tidal zone of each study location. Artificial structures having four substrate types were deployed at a depth of 2 m from the water surface in all 3 sampling locations and sampled once in two months’ intervals. Randomised Complete Block Design analysis were conducted using number of individuals, percentage area covers, study locations, monsoon seasons and tide hitting attributes as variables. A total of 49 taxa were recorded during the course of the study. Highest number of species were recorded from phylum Mollusca. Oysters species were the dominant macro fouling organisms in terms of percentage area cover in Dikkowita (33.39% cover) and Wellawatte (49.80% cover) study locations. Recording the presence of three Non-indigenous species; Isognomon alatus, Cassostrea virginica, Ostrea edulis together with four globally known invasive species: Balanus amphitrite, B. reticulatus, Perna viridis, was alarming. Randomised Complete Block Design analysis for both biofouling organisms number and percentage area coverage confirmed a significant paired interaction between tide hitting attributes and study locations. Similarly, significant paired interactions were yielded between monsoon seasons and study locations. Submerged structure sampling recorded tube-worm species as the climax species in the wooden substrate, conversely no climax species were observed on other substrate types.Keywords: Biofouling, Port of Colombo, Port biological baseline survey, Non-indigenous specie

A method to estimate trends in distributions of 1 min rain rates from numerical weather prediction data

It is known that the rain rate exceeded 0.01% of the time in the UK has experienced an increasing trend over the last 20 years. It is very likely that rain fade and outage experience a similar trend. This paper presents a globally applicable method to estimate these trends, based on the widely accepted Salonen-Poiares Baptista model. The input data are parameters easily extracted from numerical weather prediction reanalysis data. The method is verified using rain gauge data from the UK, and the predicted trend slopes of 0.01% exceeded rain rate are presented on a global grid

Aminoglycoside-Induced Phosphatidylserine Externalization in Sensory Hair Cells Is Regionally Restricted, Rapid, and Reversible

The aminophospholipid phosphatidylserine (PS) is normally restricted to the inner leaflet of the plasma membrane. During certain cellular processes, including apoptosis, PS translocates to the outer leaflet and can be labeled with externally applied annexin V, a calcium-dependent PS-binding protein. In mouse cochlear cultures, annexin V labeling reveals that the aminoglycoside antibiotic neomycin induces rapid PS externalization, specifically on the apical surface of hair cells. PS externalization is observed within ~75 s of neomycin perfusion, first on the hair bundle and then on membrane blebs forming around the apical surface. Whole-cell capacitance also increases significantly within minutes of neomycin application, indicating that blebbing is accompanied by membrane addition to the hair cell surface. PS externalization and membrane blebbing can, nonetheless, occur independently. Pretreating hair cells with calcium chelators, a procedure that blocks mechanotransduction, or overexpressing a phosphatidylinositol 4,5-biphosphate (PIP2)-binding pleckstrin homology domain, can reduce neomycin-induced PS externalization, suggesting that neomycin enters hair cells via transduction channels, clusters PIP2, and thereby activates lipid scrambling. The effects of short-term neomycin treatment are reversible. After neomycin washout, PS is no longer detected on the apical surface, apical membrane blebs disappear, and surface-bound annexin V is internalized, distributing throughout the supranuclear cytoplasm of the hair cell. Hair cells can therefore repair, and recover from, neomycin-induced surface damage. Hair cells lacking myosin VI, a minus-end directed actin-based motor implicated in endocytosis, can also recover from brief neomycin treatment. Internalized annexin V, however, remains below the apical surface, thereby pinpointing a critical role for myosin VI in the transport of endocytosed material away from the periphery of the hair cell