A preliminary weather model for optical communications through the atmosphere

A preliminary weather model is presented for optical propagation through the atmosphere. It can be used to compute the attenuation loss due to the atmosphere for desired link availability statistics. The quantitative results that can be obtained from this model provide good estimates for the atmospheric link budget necessary for the design of an optical communication system. The result is extended to provide for the computation of joint attenuation probability for n sites with uncorrelated weather patterns

Atmospheric propagation effects relevant to optical communications

A number of atmospheric phenomena affect the propagation of light. The effects of clear air turbulence are reviewed as well as atmospheric turbidity on optical communications. Among the phenomena considered are astronomical and random refraction, scintillation, beam broadening, spatial coherence, angle of arrival, aperture averaging, absorption and scattering, and the effect of opaque clouds. An extensive reference list is also provided for further study. Useful information on the atmospheric propagation of light in relation to optical deep space communications to an earth based receiving station is available, however, further data must be generated before such a link can be designed with committed performance

Chloroplast Division Protein ARC3: Effects on FtsZ2 Assembly and GTPase Activity

Chloroplasts evolved from cyanobacterial endosymbiotic ancestors and their division is a complex process initiated by assembly of cytoskeletal FtsZ proteins into a ring structure at the division site (Z-ring). The cyanobacterial Z-ring positioning system (MinCDE proteins) is also conserved in chloroplasts except that MinC was lost and replaced by the eukaryotic ARC3. Both MinC and ARC3 act as negative regulators of FtsZ assembly, but ARC3 bears little sequence similarity with MinC. Here, light scattering assays, co-sedimentation, light microscopy, GTPase assay and transmission electron microscopy in conjunction with single particle analysis have been used to elucidate the structure of ARC3 and its effect on its main target in chloroplast division: FtsZ2. Analysis of FtsZ2 in vitro assembly reactions in the presence and absence of GMPCPP showed that ARC3 promotes FtsZ2 debundling and disassembly of existing filaments in a concentration-dependent manner and requires GTP hydrolysis. 3D reconstruction of ARC3 revealed an almost circular molecule in which the FtsZ-binding N-terminus and the C-terminal PARC6-binding MORN domain are in close proximity and suggests a model for PARC6-enabled binding of ARC3 to FtsZ2. The latter is corroborated by in vivo data

Evaluation and Comparison of the Morphological and Histopathological changes induced by ER:YAG Laser and burs on Enamel, Dentin and Pulp Tissue

The cavity preparation between the convent ion al methods and lasers were compared in 18 patients with 40 samples. • The patient acceptance was good with the laser procedures like that of the conventional methods. • The time required to prepare the cavity with laser was (6.50±1.63 minutes) slight longer than the conventional methods (4.65±0.93 minutes). • On the Scanning Electron Microscope analysis the surface of lased cavity was irregular in appearance with absence of smear layer. • The ground sect ions of the teeth in both methods showed no differences. • The histopathological study of the decalcified sect ions showed that there was no demonstrable pulpal hyperaemia and inflammation in both the methods. In conclusion, there were no significant difference s in the ground sect ion and decalcified sect ion with respect to laser and bur. • However with Scanning Electron Microscope there were significant surface changes between the groups with the laser showing a surface that is beneficial for adhesive restoration and features which suggest that they could reduce the post operative hypersensitivity

Case – Calcification of the epiglottis

This 70-year-old male patient presented to the Department of Oral and Maxillofacial Radiology for CBCT imaging prior to implant therapy (Figure 1

Effects of Trade Openness on Economic Growth: The Case of African Countries

The relationship between trade and productivity has not been established theoretically. Some researchers have indeed found some, if not complete, support for the view that increasing openness has a positive impact on productivity. This study used a Cobb-Douglas production function as in Miller and Upadhyay (2000) to estimate the impact of FDI, exchange rate, capital-labor ratio and trade openness on GDP for 38 African countries from 1980 to 2008. Data were transformed to natural logs and estimated using alternative panel models; which included one- or-two-way fixed or random effects models. The results found trade openness having a positive relationship with GDP; which is comparable to findings of Ahmed et al.; (2008).Trade Openness, Productivity, Africa, Cobb Douglas Production Function., International Development, International Relations/Trade, Productivity Analysis,

Design And Implementation Of Multibit Flip-Flop Utilizing Verilog Hdl

Power consumption is an important issue in modern low-power, high-frequency VLSI design. Joining these methods that group account flows and settings also allows money control. We are considering the MBFF alignment and its collaborative energy with the FF information for clock change probabilities. A probabilistic model is triggered to increase normal vital sign buffers by collecting FFs by extending your request for information to the probabilities of turning the clock. Front-end configuration flow, guided by reflections on the physical design of a 65nm 32-bit 28nm MIPS mechanical system processor. It was shown in 24% and 18% individually, contrasting and specifically with the common FF. On mutual funds it was due to the DDCG format in the MBFF

Performance Evaluation of EM and K-Means Clustering Algorithms in Data Mining System

In the Emerging field of Data Mining System there are different techniques namely Clustering, Prediction, Classification, and Association etc. Clustering technique performs by dividing the particular data set into associated groups such that every group does not have anything in common.Clustering algorithms have emerged as an alternative powerful meta-learning tool to accurately analyze the massive volume of data generated by modern applications. Actually the main goal is to classify data into clusters such that objects are clustered in the same cluster when they are related according to particular metrics. Classification is the organization of data sets into some predefined sets using various mathematical models. This research discusses the comparison of algorithms K-Means and Expectation-Maximization in clustering. Empirically, we focused on wide experiments where wecompared the best typical algorithm from each of the categories using a large number of real or bigdata sets. The effectiveness of the Expectation-Maximization clustering algorithm is measured through a number of internaland external validity metrics, stability, runtime and scalability tests

Ga3-Mediated Dormancy Alleviation In The Reputed African Potato, Hypoxis Hemerocallidea

Background: Hypoxis hemerocallidea, arguably the most well-known medicinal species in South Africa, has been the subject of intensive harvesting from the wild leading to recent conservation concerns. The seeds of this species do not propagate easily and can lie dormant for up to twelve months.Materials and Methods: In the in vitro germination experiments water, acid and chemical pre-sowing treatments were performed to determine the germination response of this species in both light and dark conditions. In the ex vitro experiment, intact seeds were sown and left to germinate in a potting soil mix under greenhouse conditions.Results: Highest levels of germination (36.7-60.0% in the light and 36.7-46.7% in the dark) were achieved by treating mechanically scarified seeds with GA3 at various concentrations for 24 h. This was followed by scarified seeds soaked in water (26.7% in the light and 23.3% in the dark). Similar results (23.3 and 26.7%) were obtained in the 1% and 4% KNO3 treatments, respectively, under light conditions only. The fastest time to germinate was two days and was obtained in the 1200 ppm GA3 treatment in both light and dark conditions. Ex vitro germination of H. hemerocallidea seeds under greenhouse conditions was unsuccessful.Conclusion: H. hemerocallidea displays physical and non-deep physiological dormancy where pre-sowing treatments are required before the seeds will germinate.Keywords: medicinal plant; dormancy; GA3; pre-sowin

Are you responsible and accountable for your actions?

In all walks of life we are accountable for our actions. However in dentistry the scope and extent of one’s responsibilities may not always be obvious. This paper aims to remind clinicians of their need to be cognisant of some fundamental principles, and to ask themselves certain relevant questions before embarking on any procedure. It makes special reference to the obligations associated with the increased use of dental imaging modalities. It does not purport to be a comprehensive review into any specific dental condition or treatment modality, but is rather a broad overview and reminder of their ethical obligations with respect to their “duty of care”