Scientific Research and Essays

  • Oral Appliances Indications in Obstructive Sleep Apnea

    Introduction: Obstructive sleep apnea (OSA) is a respiratory disorder that causes upper airway obstruction during sleep. The performance of a dentist in patients with OSA is evidenced by the preparation and indication of the Oral Appliances (OA) as a treatment measure. The OAs are devices used in the oral cavity during sleep avoiding an obstruction of the oropharynx. These are classified as lingual, mandibular and/or conjugate control devices. Objective: To describe the OA models and to make explicit the indication of each one for the type of apnea in question. Methodology: A database was searched (Pubmed, Scielo) using the following documents: Intraoral device, lingual control, mandibular advancement, indication. Publications from 2010 to 2017 were included in the Portuguese and English languages whose content was pertinent to the theme. Results and Discuss: 60 articles were found. Of these, 24 directly addressed the theme and only 4 articles were used. A practicality and comfort provided by the OAs make them more accepted and indicated for OSA. The indications for the use of OAs include: patients with the diagnosis of mild, moderate and severe OSA. The lingual control device is based on control of the positioning of the aforementioned organ and is indicated for patients with extensive dental loss, edentulous, periodontal problems, temporomandibular dysfunction and bruxism. The most commonly indicated mandibular advancement OA is retained by teeth and protrudes the mandible in order to increase the volume of the oropharynx. Ideal for patients with at least 10 teeth in each arch and on a semi-flexible model for transport conditions, small mandibular movements. Conclusion: The indication of AIO depends on the oral cavity conditions and the general health of the patient and are potentially capable of improving the quality of life of an OSA carrier.

  • Physicochemical Analysis of Hora and spring water bodies in Anderacha Woreda, Sheka Zone, South west Ethiopia

    Access to safe water is a worldwide need though, many of the world’s population lack access to adequate and safe water. Contaminated water jeopardizes both the physical and social health of all people. Hence the purpose of the research was to assess the physicochemical analysis of hora/salty unprotected springs and protected springs in Anderacha wereda, sheka zone south west of Ethiopia. Water samples collected were analyzed for physicochemical parameters such as temperature, pH, conductivity, total hardness,Cl-, NO3-,NO2-,CO32-,PO43-,Co,Cd,Cu,Zn,Mn,Fe, Mg,Ca,Cr,Ni and Pb using standard analytical methods, Analysis of official analytical chemist 1990. . The obtained results of each parameter are comparable with the standard values set by WHO and other national guidelines. The values of most physicochemical parameters were found to be within the recommended permissible limits except temperature, Fe,Cu and Mn. These outcomes demonstrate the need to come up with water source protection strategies for the study area.


    The mine of Trepca in Stanterg has had a big economic importance since the earlier period to now. Even if there is not any written source about the development in this times, some signs prove the begining of the mine activities since the ilyrian period. The archelogyc documents prove the cink and leaden in TREPCA, are used for more than 2000 years. The documents of middle ages prove that the namr of “Trepca” for the first is mentioned in the Dubrovnik’s archive in 1303. In this study we’re going to treat the destroyment of Trepca, during the Ottoman leading since 1445 till the 20th cebtury. The historical importance of Trepca’s mine is Stanterg is a big and valuable as it is impossible to describe it in a few words. However, I have tried to show it is a science manner and as a historical, economic and social issue during the 20th century.

  • The Theory of Relativity is an Error in Physics; the Speed of Light excludes the Laws of Optics

    Physicists measured the propagation of light in vacuum and matter through experiments with light over the course of several centuries. The Laws of Optics were derived from these measured results. The Laws of Optics were verified repeatedly via real experiments with light and used in the calculations of optical instruments that work properly. The Laws of Optics accurately define the propagation of light in vacuum and matter. All the theories of the propagation of light that ignore the Laws of Optics can, therefore, be considered an error in physics. The theories and laws of propagation of light in matter were written by famous physicists, such as Isaac Newton (1670), Christiaan Huygens (1650), Augustin-Jean Fresnel (1819), and Thomas Young (1800). The law of propagation of light in matter was described by Snell in 1620. Snell’s law is the law of the light refractive index in matter. Optical instruments are calculated according to the Laws of Optics, so by their correct operation they confirm the validity of the Laws of Optics. Two hundred years ago, André-Marie Ampére expressed the basic approach in discovering the laws of physics: “First observe the facts, to vary their circumstances as much as possible, to accompany this first task with exact measurement so as to deduce from them the general laws based solely upon experience, and to deduce from these laws, independently of any hypothesis on the nature of the forces that produce the phenomena, the mathematical value of these forces”. This approach to the measurement of the light propagation is now used in all the laboratories around the world and, therefore, can be considered as objective and accurate.

  • The Doppler effect of spectral lines and shift of the frequency of light in space

    The Doppler effect of spectral lines in space is the change in the frequency of light emitted by an illuminated celestial body, which moves closer or farther away from the Earth in vacuum. A description of the change in light frequency is realized with the assumption that an illuminated celestial body in vacuum moves closer or farther away from the observer in vacuum. In this case, the propagation of light of the moving celestial body toward an observer also occurs in vacuum. Everywhere on Earth and in the surrounding space there is matter, so the choice of vacuum for the Doppler effect and the propagation of light from the moving celestial body toward the observer is not correct. From the observation of space as we know it, such as galaxies and stars, the area between the celestial bodies consists of a vacuum, but in some restricted spaces of the universe there is a transparent mass – gas, that moves at high speed against Earth. These spaces in universe filled by gas were called “intergalactic bubbles of gas” by astronomers. The propagation of light on the trajectory from an illuminated celestial body toward the observer takes place not only in a vacuum, but alternately also in the gases of intergalactic bubbles, respecting the laws of optics. The topic of the propagation of light in the universe is a very broad topic. For further information, please see reference [1], [2] and [3].

  • Market Chain Analysis of Koka Reservoir Fish in Ethiopia

    This study analyzed the fish market chain of Koka reservoir in Ethiopia which is found in Oromia Region, East shoa and Arsi zones. The objectives of the study were to assess the structure, conduct and performance of fish marketing as well as identify factors affecting fish market supply. The study was based on the data obtained from a sample of 104 fishers and 36 traders in the fish market chain. Both descriptive and econometric methods were employed to analyze the data. About 65% Tilapia (Coroso), 21% Catfish (Ambanza) and 14% Carp (Abasamuel) were the type of fish which dominantly appear in the day to day marketing activities of the fishers. The major determinant factors of market supply were estimated by using multiple linear regression models. The fish market performance was also measured using indicators of marketing margins. According to the results, there were three kinds of fish marketing channels i.e fishers to consumers, fishers to retailers then consumers, fishers to fishery cooperatives, wholesalers then consumers. The result showed that transportation and filleting costs were the largest costs of marketing followed by gutting cost. The price of a kilogram of filleted tilapia varied from 18 birr at landing site to 75 birr at Atiklt Tera in Addis Ababa. The Ordinary Least Square results indicated that education level, availability of credit facility and ownership of fishing license significantly affected the amount of fish supplied to market by fishers in the study area. Expanding adult education in fishery community, facilitating access to credit facility and encouraging fishers to be legal is very important for better harvesting and marketing of fish.

  • Adsorption Kinects and Isotherms for Removal of Rhodamine B

    The present work aims to investigate the removal of Rhodamine B dye (RB) from aqueous solution by using adsorbents prepared from alum sludge (AS) and Mud sludge (MS) of drinking water treatment plant. The effect of dye concentration, contact time, pH, temperature and adsorbent dose on the dye removal was studied. The equilibrium adsorption data of RB dye on the developed adsorbents were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) Isotherms. The sorption data fitted well to Langmuir isotherm model. The maximum dye removal efficiency was observed at pH 7, contact time 90 min,and 0.1-0.25 gm dosage for both (AS) and (MS) adsorbents . Also, four kinetic models such as Pseudo-first order, Pseudo-second order, Intraparticle diffusion and Elovich models were tested to interpret the experimental data. The kinetic experimental data were fitted well to Pseudo-second order model.The thermodynamics parameters of adsorption system indicated spontaneous and endothermic process. Results indicate the effectiveness of the developed adsorbents for removing RB dye.

  • Conventional and Molecular Diagnostic Tools for Genital Tuberculosis

    Mycobacterium tuberculosis, the etiological agent for tuberculosis, has been comprehensively studied for over a century now. But the disease still remains a major public health concern today in the 21st century. The precised and authenticated diagnosis is mandatorily pre-requisite to proper medication and cure of tuberculosis that specifically interferes and thus complicating physiological and biochemical mechanism of setting pregnancy in Indian women ranging between the age of 18-40 years. Various combinations of conventional and modern diagnostic tools were considered and monitored for the best possible option. Data obtained from the present study provides new insights into PCR with modified and advanced protocol likely to be competent as a novel molecular diagnostic technique for rapid and précised diagnosis of genital tuberculosis causing infertility in developing countries.

  • Direct measurement of the absolute light refractive index of air

    The paper describes the direct measurement of the absolute index of refraction of air double-Michel son interferometer without knowing parameters of the air, namely, pressure, temperature and chemical composition of the air. The direct measurement and the calculation of absolute index of refraction of air double Michelson interferometer is used as the applicable laws of optics.

  • Time Series Analysis: A Hydrological Prospective

    The analysis of time series is based on the assumption that successive values in the data file represent consecutive measurements taken at equally spaced time intervals. There are two main goals of time series analysis: (a) identifying the nature of the phenomenon represented by the sequence of observations, and (b) forecasting or predicting future values of the time series variable. Both of these goals require that the pattern of observed time series data is identified and more or less formally described. Once the pattern is established, one can interpret and integrate it with other data (i.e., Use it in the theory of the investigated phenomenon, e.g., Seasonal commodity prices). Regardless of the depth of one’s understanding and the validity of our interpretation (theory) of the phenomenon, one can extrapolate the identified pattern to predict future events. This paper discusses about how to analyze time series data, what are its goals, types of time series data, and models available to analyze time series data.