333 research outputs found
PENERAPAN GENERALIZED ADDITIVE MODELS DENGAN AUTOKORELASI DALAM PEMODELAN ANOMALI SUHU PERMUKAAN LAUT
Anomali Suhu Permukaan Laut (AnoSPL) di Samudera Hindia, atau yang lebih sering disebut dengan Indian Ocean Dipole (IOD) merupakan salah satu parameter yang mempengaruhi kondisi iklim di Indonesia khususnya di pulau Sumatera. AnoSPL juga erat kaitannya dengan kejadian iklim ekstrim. Terdapat beberapa fitur iklim utama yang mempengaruhi AnoSPL diantaranya suhu udara, curah hujan, kelembaban relatif, kecepatan angin, dan radiasi matahari. Analisis yang mengkaji kejadian-kejadian iklim ekstrim dibutuhkan untuk memperkecil dampak buruk karena adanya kejadian AnoSPL tersebut. Salah satu metode untuk pendugaan model dalam kajian ekstrim adalah Generalized Additive Models (GAM) dengan autokorelasi. Metode GAM dapat mengakomodasi dengan baik adanya pengaruh non linier antar variabel respon dengan variabel prediktor. Data yang digunakan dalam penelitian ini merupakan data deret waktu dimana residual antar pengamatan saling berkorelasi dari waktu ke waktu. Data yang digunakan merupakan data harian dari tahun 2006 s.d. 2017 dan terdapat gap didalamnya. Tujuan dari penelitian ini adalah untuk mendapatkan model yang representatif berdasarkan pola dari kejadian AnoSPL, mengetahui faktor-faktor yang berpengaruh terhadap AnoSPL, serta mengetahui perbandingan antara data ramalan dengan data aktual. Hasil yang diperoleh menunjukkan bahwa model terbaik GAM dengan autokorelasi adalah model GAM dengan memasukkan variabel bulan dan tahun dengan struktur autokorelasi bulan. Faktor yang berpengaruh terhadap AnoSPL adalah suhu udara, bulan, dan tahun. Hasil ramalan untuk AnoSPL tahun 2018 yang diperoleh menjauhi data aktual namun memiliki fluktuasi yang sama dengan data AnoSPL aktual. Namun dengan menggunakan data tahun 2015 s.d. 2017 diperoleh hasil ramalan telah mendekati data aktual dengan empat ukuran akurasi peramalan terendah yaitu MSE sebesar 0,256, MSLE sebesar 0,307, RMSE sebesar 0,506, dan RMSLE sebesar 0,553. Berdasarkan hal tersebut maka dapat disimpulkan bahwa gap pada data mempengaruhi urutan waktu sehingga mempengaruhi hasil peramalan dari model GAM dengan autokorelasi dalam penelitian ini.Kata kunci: AnoSPL, IOD, fitur iklim, GAM dengan autokorelas
Synthesis and Characterization Of Fe-modified Imogolite Nanotubes
During the past decades, and after introducing the most famous carbon nanotubes, the main role in these fields has been playing by the single- and multi-wall carbon nanotubes which have received tremendous research interest due to their superior mechanical, chemical, electrical and thermal properties. However, several problems in carbon nanotube technology, such as high-temperature process with low yield product, imprecise control over nanotube dimensions and chirality, limitations of chemical composition, intrinsic color of nanotubes which limits their application as nanofiller in transparent hybrid materials, low compatibility of carbon nanotubes with human body in bio-applications and the most important, in recent years, effect of carbon nanotubes on human health and environment because of their potential toxic nature, encouraged the research for analogue structure among inorganic materials and the possibility of applying them in other fields, such as catalysis and ion adsorption.Inorganic nanotubes like MoS2 and WS2 were the first inorganic nanotubes that succeeded the discovery of carbon nanotubes and in the following years, other metal oxide/hydroxide nanotube structures have been reported. Among the inorganic nanotubes, which have been developed in recent years, imogolite (IMO, chemical formula (OH)3Al2O3Si(OH)), a natural alumino-silicate clay mineral, recently entered this nanotechnologic scenario. It was discovered for the first time 1962 in Japanese soils of volcanic origins but its structure was determined ten years later. Being an analogue material to carbon nanotubes, IMO type materials can represent an intriguing different source for new technological potential applications as anions/cations retention from water, catalysis, gas adsorption, separation and storage, scaffold for biomedical applications and inorganic nanofiller for polymer matrixes.
The main features of imogolite is the crystalline organization of its walls, folded to create a nanotube with two distinct surfaces: an inner surface presenting free silanol groups and an outer surface characterized by hydroxyl groups bridged between two octahedral aluminum atoms. Since, variables such as purity, composition, reproducibility, and specifically designed features can be often better controlled in synthetic procedures rather than using natural clay specimens (which typically contain impurities and are often not easily available), synthetic single walled imogolite nanotunes with high monodispersity in diameter was obtained for the first time in 1972 by a sol-gel synthesis in acid environment.
Present PhD project is going to describe the developments obtained in imogolite research field, concerning the synthesis and characterization of a new kind of modified imogolite nanotubes by iron inclution in nanotubes outer surface, either by direct or post-synthesis reactions, as compared to unmodified synthetic IMO. A series of samples of iron-doped IMO, with a range of iron content, were obtained. To investigate the role of Fe ions in nanotube formation and the effect of Fe structural position on nanotubes textural properties, they were characterized by means of low angles X-ray Diffraction (XRD); IR spectroscopy (FT-IR); Transmission Electron Microscopy (HR-TEM); energy dispersive spectroscopy (EDS) and N2 sorption isotherms at -196 °C, indicating the limited level of Fe inclusion into nanotube structure, about up to 1 %wt Fe. The higher amount of Fe will hinder tube formation. The obtained modified samples by direct synthesis show more closely packing in bundles and presents slightly larger inner pores. Then, their physico-chemical properties were compared to those of proper IMO. Several experimental results are reported of nature and structural positions of Fe species in the samples obtained by direct (Fex-IMO) or post synthesis method (Fex-loaded-IMO) by Diffuse Reflectance (DR) UV-Vis pectroscopy, Raman spectroscopy, magnetic test and Electron Paramagnetic Resonance (EPR) spectroscopy which indicate the preferential isomorphic substitution of Fe for Al in the sample prepared by direct synthesis (Fex-IMO) and of the preferential formation of Fe2O3 clusters in that obtained by post-synthesis doping (Fex-loaded-IMO).
Same as other nanoporous aluminosilicate materials, IMO nanotubes materials contain considerable amount of water in their pores in ambient condition that influences and governs their properties. Therefore, hydration/dehydration behavior of bare and Fe-modified nanotubes was of paramount importance in dictating the operating conditions for any application requiring a surface interaction like catalytic activity or ion adsorption. Accordingly, the behavior of hydrated Imogolite markedly depends on thermal pre-treatments, which has been investigated by several complementary methods (XRD, IR spectroscopy, TG/DT analysis and N2 sorption isotherms at -196 °C). Obtained results show that, modification of imogolite nanotubes by iron either by direct or post synthesis, accelerate dehydroxylation and decrease their thermal stability, by likely forming some structural defects, able to catalyze silanols condensation. Such defects may be ascribed to those Fe ions substituting for Al ions that likely form also by post-synthesis procedure. After removing of water present at both the external and internal surfaces at 250 oC under residual vacuum equal to 10-3 mbar, inner âĄSiOH groups will be accessible to probes.
Surface acidic properties and accessibility of surface groups were investigated in gas and water media. In gas phase, surface acidic properties investigated by combination of IR spectroscopy and interaction with probe molecules (CO and NH3). Moreover a catalytic reaction: epoxidation of propylene by O2 over the obtained samples as catalyst was carried out to provide more information about surface acidity of Fe-modified samples in gas phase. According to the results, with both modified samples, when Fe substitutes for Al, at the outer surface Fe(OH)Al groups occur, the intrinsic acidity of which is only marginally different from that of Al(OH)Al. Fe(OH)Al groups likely act as crystallization centres for the growth of Fe2O3 nanoclusters, bearing less acidic OH groups.
The acidity of modified samples were studied in water, as shown by ïș-potential measurements and interaction with (acid orange 7, an organic sodium salt with formula C16H11N2NaO4S) AO7 molecules, for two important reaction: adsorption of AO7 molecules and catalytic reaction azo-dye molecule degradation by H2O2. In water, Fe(OH)Al bridged groups, which are slightly less acidic than Al(OH)Al groups, but provide accessible Fe3+ sites that may be accessible to species able to coordinate iron, as observed in the case of AO7-, leading to a higher efficiency towards the retention of such moiety and, more generally, of anions in aqueous solution. Finally we can conclude that Interaction with AO7- in water solution occurs in different ways, as documented by the observed pH changes: i) with proper IMO, AO7- anions preferentially adsorb via H-bonding; ii) with Fe1.4-IMO, Fe3+ cations of Fe(OH)Al groups act coordination centers for N atoms in the AO7- moiety; iii) with Fe1.4-loaded-IMO, Fe2O3 nanoclusters likely hinder AO7- adsorption.
The best condition for degradation if AO7 was observed in the presence of IMO sample as catalyst, by formation of very active OOH groups and then carries out an intermolecular rearrangement with the neighboring adsorbed AO7 molecules to achieve the degradation. In this case higher acidity of Al(OH)Al groups in water provide reacitve sites. Fe(OH)Al groups which are more basic in water environment seems to be weaker in H2O2 decomposition. Therefore IMO with more than 95% of degradation just in a few minutes could be proposed as a new candidate for waste water treatment
CALCIUM ION REQUIREMENT FOR PROLIFERATION OF BACTERIOPHAGE ΊΌ-4
SHAFIA, FRED (University of Nebraska, Lincoln), AND T. L. THOMPSON. Calcium ion requirement for proliferation of bacteriophage ΊΌ-4. J. Bacteriol. 88:293-296. 1964.-Divalent ions are essential for proliferation of phage ΊΌ-4. Small amounts of citrate interfere with efficient adsorption of phage to the host cells. Penetration of phage material into the cell is strictly dependent on divalent ions and is inhibited by low levels of citrate. Inhibition of infection can be partially reversed, in early latent period, by calcium ions. Synthesis of new phage particles is also dependent on divalent ions. Addition of citrate to infected cell suspensions significantly reduced the number of phage progeny produced. Chelates such as phosphate and citrate rapidly inactivated the free phage particles at 65 C. Chelate inactivation of phage is not reversible; however, it can be prevented to some degree by calcium ions
EVALUATION OF POLYHERBAL UNANI SHAMPOO USED IN DANDRUFF
Objective: The objective of the study was to evaluate the laboratory parameters of polyherbal Unani formulation with simple shampoo base used in seborrheic dermatitis (Huzaz) of scalp.
Methods: Evaluation of test drug formulation with shampoo base was done for its appearance, pH, % of solid contents, wetting time, density, viscosity, dirt dispersion test, froth test, and skin irritation test.
Results: Polyherbal formulation along with simple shampoo base was dark brown in color, thin in consistency, and with pungent aroma. pH of poly herbal formulation was 8.27 which will have positive effect on greasy and thin hairs. Solid contents were moderately easy to wash. Wetting time was 200 s, density was 1.17 g, and viscosity was 2.33 moderately good. Froth test showed froth >8 cm. Skin sensitivity on albino rats showed no allergic reaction.
Conclusion: Polyherbal Unani formulation can be a promising drug with least side-effects and cost-effective in treating dandruff which relapses every now and then
The Effect of Organizational Well-Being on Organizational Commitment in Telecommunication Employees
At work, an effective environment will increase a person's work productivity. Efforts to study this condition can be made by examining organizational well-being. This research was conducted to find out whether organizational well-being perceived by employees influences employee commitment to the company where they work. The population in this study was 128 telecommunication employees who were selected using stratified random sampling techniques. Data collection was carried out through an organizational well-being questionnaire developed by (I Prilleltensky, 2007) and an organizational commitment questionnaire adapted and modified from (JP Meyer, 1997) questionnaire. Hypothesis testing uses simple regression analysis techniques. The results showed that organizational well-being has a significant influence on the three components of organizational commitment, namely affective commitment, continuance commitment, and normative commitment. In this study, data was found that Organizational well-being contributes the most to affective commitment compared to other components.Dalam bekerja, lingkungan yang efektif akan meningkatkan produktivitas kerja seseorang. Upaya untuk menelaah kondisi ini dapat dilakukan dengan menelaah organizational well-being. Penelitian ini dilakukan untuk mengetahui apakah organizational wellbeing yang dipersepsi oleh karyawan berpengaruh pada komitmen karyawan terhadap perusahaan tempatnya bekerja. Populasi dalam penelitian ini adalah karyawan telekomunikasi sejumlah 128 orang yang dipilih menggunakan teknik stratified random sampling. Pengumpulan data dilakukan melalui kuesioner organizational well-being yang dikembangkan dari teori (I Prilleltensky, 2007) dan kuesioner organizational commitment yang diadaptasi dan dimodifikasi dari kuesioner (JP Meyer, 1997). Pengujian hipotesis menggunakan teknik analisis regresi sederhana. Hasil penelitian menunjukkan bahwa organizational well-being memiliki pengaruh yang signifikan terhadap ketiga komponen organizational commitment yaitu affective commitment, continuance commitment, dan normative commitment. Dalam penelitian ini, didapati data bahwa Organizational well-being berkontribusi terbesar terhadap affective commitment dibandingkan dengan komponen lainnya
Innovation Process is Facilitated in Virtual Environment of R&D Teams
Innovation is becoming the most important key issue for company's success in the 21st century. In the competitive environment it is necessary for the enterprises to put together different capabilities and services with the goal. It is widely accepted that innovation can be better achieved by working in team particularly in the virtual environments. The employed web services technology, although very popular nowadays but it is still not mature enough, so dealing with it can bring new findings. Virtual teams base on information technology are formed to facilitate transnational innovation processes and it should be noted that innovation has a positive impact on corporate performance if it is well guided. This has the pronounced effect when it comes to the learning issues as the virtual preconditions persist. In this environment the possibility of getting closer to the interest of learner from the new environment raise as the barriers being imposed by the service provider is reduced and the freedom of what is require to learn is improved. Information and communication technology has brought about significant changes in organizations and produced important benefits, including in the areas of innovation which is recognized as a prime source of national competitive advantage. This contribution proposes a conceptual model for understanding and analyzing the process of virtual R&D team as an innovation and technology assimilation facilitator when it comes to the issue of conveying innovative message for learning by individuals. The context of the knowledge-based economy introduces a major shift from serial to simultaneous R&D in the way of idea conception to technology creation is conceived. This paper briefly reviews the existing perspectives on virtual teams and their effect on innovation and technology regarding the learning capability which is being altered. It also discusses the main characteristics of virtual teams and clarifies the different aspects of virtual team application in the topic. To support the theoretical analysis, this paper provides a comprehensive review based on authentic and reputed publications. We argue that scanty research has been conducted to facilitate understanding the problem of systematically governing creative innovation toward a technology through virtual R&D teams in the atmosphere of educating individuals based on what they interest them to learn.Virtual team; e-learning; Innovation; Research and development, Learning
Consideration of the virtual team work and disabled citizens, as promising opportunity providers for the e government infrastructure's formation
The Information area has revolutionized the workplace. Douglas Kruse, a professor of human resources and the director of the program for disability research at Rutgers University, states that 7% of employed persons with disabilities work 20 hours or more a week from home. While some modern countries have established âvirtual teamsâ, which are said to be comprised of people who are geographically scattered and who work across boundaries of space and time using computer driven communication technologies, it is also true that many developing countries remain structured around conventional face-to-face teams. A motive toward virtual team working may be cost effectiveness. Increasing transport and human resource costs makes face to face contact less attractive unless they are essential. In an environment of urging to move into the direction of governing the activities via electronic moves, consideration of the individuals who deliver their services to the society in the form of virtual teams are of the primary value which should accelerate the E culture while E government is aimed at. By reviewing literature and theories, this paper present the definition and characteristics of virtual teams. A comparison of different types of virtual teams along with the application, strengths and limitations of them regarding as the promising elements of e activities are elaborated. Persons with disabilities are entitled to and capable of the same career options as their non-disabled counterparts and increasing numbers of them are taking advantage of virtual workplaces therefore creating a condition to facilitate the cultivation of e moves in the society.Virtual team, Virtual Workplaces, Disabled Citizen, Workplace, E Government
SHIFTING STUDENTSâ AWARENESS OF GEOMETRICAL CONCEPTS THROUGH LESSON STUDY
Studentsâ performance in geometry and hence, their geometric thinking remain a concern for researchers globally. This quasi-experimental research design aims to investigate the effects of Phase-Based Instruction (LS-PBI) using Geometerâs Sketch Pad to reveal Thai students awareness of geometric concepts. Three groups of mixed ability Grade 7 students (aged 12 â 13) were chosen as participants in one of the schools in Yala Province, Thailand. These groups were taught the topic of Properties of 2D and 3D geometric shapes in a cycle of three instructions by three different teachers engaging in Lesson Study method. A twelve-item multiple choices test was administered to students in each group before and after each lesson study session to assess their understanding of geometrical concepts. Findings of the pre-tests and post-tests revealed that LS-PBI using GSP was effective in revealing studentsâ shifts in awareness of geometrical concepts.
Keywords: Geometerâs Sketchpad, Geometric Thinking, Geometry, Lesson Stud
CHALLENGES IN THE MANAGEMENT OF BRONCHIOLITIS
ABSTRACTObjective: This study aims to review and evaluate current medication and to provide practical guidelines to the practitioners managing children withbronchiolitis.Methods: A 6-month retrospective study was carried out in the Department of Paediatrics in Tertiary Care Hospital, a 350-bedded multispecialtyhospital to review the management of bronchiolitis. A total of 60 cases selected from July 2014 to December 2014 were included in the study. Patientdata and prescription details were recorded and analyzed accordingly.Results: About 58.3% of bronchiolitis cases were reported in the age group of <1 year, 26.6% in the age group of 1-2 years and 15% casesreported at the age >2 years. Commonly reported symptoms in different cases include 85% of cases with fever, 90% with a cough, 93.3% withcold, 30% with vomiting, 35% with breathlessness, 33.3% with loose motions, and 68.3% with wheezing. A single broad-spectrum antibioticwas used in 68.3% cases, two broad spectrum antibiotics in 26.6% of cases, and three or more combinations in 5% of cases to prevent bacterialcoinfections. A careful assessment of study has evaluated that antiviral therapy was not used in any of the cases to avoid antiviral resistancebut broad-spectrum antibiotics were most commonly prescribed for a viral respiratory illness which is generally self-limiting adding to thethreat of antibiotic resistance. Bronchodilators and corticosteroids were routinely used. As per current Standard Treatment Guidelines for themanagement of bronchiolitis, the priority has been given to adequate rest, intravenous fluids, symptomatic therapy, and reserve antiviral therapyfor special cases. This study demonstrated the importance of routine medication review and the need of a clinical pharmacist at various levelsof clinical setup.Conclusion: From this study, it can be concluded that interventions by a clinical pharmacist are needed in taking a special effort to analyze prescriptionsand provide clinicians with a feedback involving available antiviral medications, antiviral resistance, prescription costs, limitations of antiviral agentsand updated current standard treatment guidelines.Keywords: Self-limiting, Antiviral therapy, Antiviral resistance, Antibiotic use, Antibiotic resistance
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