10 research outputs found
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Internet Subscription Plans: Thresholding, Throttling, and Zero-Rating
Internet Service Providers, or ISPs, like any other rational entity make decisions to maximize their profit. While some of their decisions are on how to attract customers, they inevitably need to control how much resources consumers utilize. In this dissertation, we focus on two different aspects of ISP's decisions, including bandwidth allocation and pricing techniques through which ISPs manage allotting their limited capacity to users with high demand, and zero-rating, which can be one of the tools through which the ISP can attract customers.
For bandwidth allocation, this dissertation discusses the data plans available for each user's monthly billing cycle. Within those, the ISPs guarantee a fixed amount of data at high rates until a byte threshold is reached, at which point the user's data rate is throttled to a lower rate for the remainder of the cycle. In practice, the thresholds and rates of throttling can appear and may be somewhat arbitrary. In this dissertation, we evaluate the choice of threshold and rate as an optimization problem (regret minimization) and demonstrate that intuitive formulations of client regret, which preserve desirable fairness properties, lead to optimization problems that have tractably computable solutions.
For zero-rating options in the ISP market, and their relation to net neutrality, we begin by introducing the concept of zero-rating, which refers to the practice of providing free Internet access to some users under certain conditions, and usually concurs with differentiation among users or content providers. Even though zero-rating is banned in some countries (India, Canada), others have either taken no stance or explicitly allowed it (South Africa, Kenya, U.S.). While there is broad agreement that preserving the content quality of service falls under the purview of net neutrality, the role of differential pricing, especially the practice of \emph{zero-rating} remains controversial. An objective of net neutrality is to design regulations for the Internet and ensure that it remains a public, open platform where innovations can thrive. We show the practice of zero-rating does not agree with that. This dissertation shows how ISPs could make zero-rating decisions to attract customers, and then show how these decisions may negatively impact the market and customer welfare, which necessitates the existence of some zero-rating regulations
Structure and Vibrational Spectra of Pyridine Solvated Solid Bis(Pyridine)silver(I) Perchlorate, [Agpy<sub>2</sub>ClO<sub>4</sub>]·0.5py
A hemipyridine solvate of bis(pyridine)silver(I) perchlorate, [Agpy2ClO4]·0.5py (compound 1) was prepared and characterized by single crystal X-ray analysis and vibrational spectroscopy (R and low-temperature Raman). Compound 1 was prepared via the trituration of [Agpy2ClO4] and 4[Agpy2ClO4]·[Agpy4]ClO4 (as the source of the solvate pyridine) in a mixed solvent of acetone:benzene =1:1 (v = v) at room temperature. The monoclinic crystals of compound 1 were found to be isomorphic with the analogous permanganate complex (a = 19.1093(16) Å, b = 7.7016(8) Å, c = 20.6915(19) Å, β = 105.515(7)°; space group: C2/c). Two [Agpy2]+ cations formed a dimeric unit [Agpy2ClO4]2, and each silver ion was connected to two ClO4− anions via oxygen atoms. The Ag∙∙∙Ag distance was 3.3873(5) Å, the perchlorate ions were coordinated to silver ions, and the Ag∙∙∙O distances were 2.840(2) Å and 2.8749(16) Å in the centrosymmetric rectangle of Ag-O-Ag-O. The stoichiometric ratio of the monomer [Agpy2ClO4] and the solvent pyridine was 1:0.5. The guest pyridine occupied 527.2 Å3, which was 18.0% of the volume of the unit cell. There was no additional residual solvent-accessible void in the crystal lattice. The solvate pyridine was connected via its a-CH to one of the O atoms of the perchlorate anion. Correlation analysis, as well as IR and low-temperature Raman studies, were performed to assign all perchlorate and pyridine vibrational modes. The solvate and coordinated pyridine bands in the IR and Raman spectra were not distinguishable. A perchlorate contribution via Ag-O coordination to low-frequency Raman bands was also assigned
Structural, Spectroscopic, and Thermal Decomposition Features of [Carbonatotetraamminecobalt(III)] Iodide—Insight into the Simultaneous Solid-Phase Quasi-Intramolecular Redox Reactions
[κ2-O,O′-Carbonatotetraamminecobalt(III)] iodide, or [Co(NH3)4CO3]I, named in this paper as compound 1, was prepared and characterized comprehensively with spectroscopic (IR, Raman and UV) and single-crystal X-ray diffraction methods. Compound 1 was orthorhombic, and isomorphous with the analogous bromide. The four ammonia ligands and the carbonate anion were coordinated to the central cobalt cation in a distorted octahedral geometry. The carbonate ion formed a four-membered symmetric planar chelate ring. The complex cations were bound to each other by N-H···O hydrogen bonds and formed zigzag sheets via an extended 2D hydrogen bond network. The complex cations and iodide ions were arranged into ion pairs and each cation bound its iodide pair through three hydrogen bonds. The thermal decomposition started with the oxidation of the iodide ion by CoIII in the solid phase resulting in [Co(NH3)4CO3] and I2. This intermediate CoII-complex in situ decomposed into Co3O4 and C-N bond containing intermediates. In inert atmosphere, CO or C-N bond containing compounds, and also, due to the in situ decomposition of CoCO3 intermediate, Co3O4 was formed. The quasi-intramolecular solid-phase redox reaction of [Co(NH3)4CO3] might have resulted in the formation of C-N bond containing compounds with substoichiometric release of ammonia and CO2 from compound 1. The C-N bond containing intermediates reduced Co3O4 into CoO and Co, whereas in oxygen-containing atmosphere, the end-product was Co3O4, even at 200 °C, and the endothermic ligand loss reaction coincided with the consecutive exothermic oxidation processes
Combined therapy of photobiomodulation and adipose-derived stem cells synergistically improve healing in an ischemic, infected and delayed healing wound model in rats with type 1 diabetes mellitus
Objective We assessed the therapeutic effects of photobiomodulation (PBM) and adipose-derived stem cell (ADS) treatments individually and together on the maturation step of repairing of a delayed healing wound model in rats with type 1 diabetes mellitus (DM1).Research design and methods We randomly assigned 24 rats with DM1 to four groups (n=6 per group). Group 1 was the control (placebo) group. In group 2, allograft human ADSs were transplanted. Group 3 was subjected to PBM (wavelength: 890 nm, peak power output: 80 W, pulse frequency: 80 Hz, pulsed duration: 180 ns, duration of exposure for each point: 200 s, power density: 0.001 W/cm2, energy density: 0.2 J/cm2) immediately after surgery, which continued for 6 days per week for 16 days. Group 4 received both the human ADS and PBM. In addition, we inflicted an ischemic, delayed healing, and infected wound simulation in all of the rats. The wounds were infected with methicillin-resistant Staphylococcus aureus (MRSA).Results All three treatment regimens significantly decreased the amount of microbial flora, significantly increased wound strength and significantly modulated inflammatory response and significantly increased angiogenesis on day 16. Microbiological analysis showed that PBM+ADS was significantly better than PBM and ADS alone. In terms of wound closure rate and angiogenesis, PBM+ADS was significantly better than the PBM, ADS and control groups.Conclusions Combination therapy of PBM+ADS is more effective that either PBM or ADS in stimulating skin injury repair, and modulating inflammatory response in an MRSA-infected wound model of rats with DM1
The association of subacute thyroiditis with viral diseases: a comprehensive review of literature
Introduction: Subacute thyroiditis (SAT), also known as de Quatrain's thyroiditis or granulomatous thyroiditis, is an inflammatory disease of the thyroid. Most of the time, it manifests in the thirties to fifties and is more common in women. SAT can have either viral or post-viral origin. Some viruses, like influenza, COVID-19, Epstein-Barr virus, cytomegalovirus, hepatitis, coxsackievirus 16, and mumps virus, have been linked to SAT development. The COVID-19 pandemic has affected people's lives all around the world and has changed our attitude toward the treatment of many diseases. It has also made us look deeper into the subject in a way that we would be able to treat this sort of disease with a newer insight. Objective: Regarding the importance of this issue, we decided to summarize our extensive searches from online databases, including PubMed, Google Scholar, Medline, Web of Science, and Scopus until February 2023, which we found effective in elucidating the association of subacute thyroiditis and viral diseases. Method: Different online databases were searched for narrative review articles, systemic review articles, and original articles, which were published until February 2023. Result: According to the included studies, we found that there is a correlation between SAT and several viruses such as Epstein-Barr virus, influenza virus, human immunodeficiency virus, cytomegalovirus, oral and cervical virus, hepatitis, dengue virus, and SARS-COV-2. The effect of each of the viral diseases mentioned in the SAT is given in the text. Conclusions: According to the results mentioned in the text, because SAT may be challenging for early diagnosis, due to the potential of classic symptoms as well as the interference of similar clinical symptoms between thyrotoxicosis and viral reactions, the correlation between SAT and viral diseases should be considered so that we can avoid misdiagnosis and lateness. National Institute of Public Health NIH – National Research Institute.
Author keywords
COVID-19; influenza; SAT; subacute thyroiditis; viral disease
The Iranian blood pressure measurement campaign, 2019: study protocol and preliminary results
Purpose Hypertension is one of the most important risk factors for premature mortality and morbidity in Iran. The objective of the Iranian blood pressure (BP) measurement campaign was to identify individuals with raised blood pressure and providing appropriate care and increase the awareness among the public and policymakers of the importance of tackling hypertension. Methods The campaign was conducted in two phases. The first (communication) phase started on May 17th (International Hypertension Day). The second phase started on June 8th, 2019, and lasted up to July 7th during which, blood pressures were measured. The target population was Iranians aged >= 30 years. Participants voluntarily referred to health houses in rural and health posts and comprehensive health centers in urban areas in the setting of the Primary Health Care network. Additionally, over 13,700 temporary stations were set up in highly visited places in urban areas. Volunteer healthcare staff interviewed the participants, measured their BP, and provided them with lifestyle advice and knowledge of the risks and consequences of high blood pressure. They referred participants to physicians in case their BP was high. Participants immediately received a text message containing the relevant advice based on their measured BP and their past history. Results Blood pressure was measured for a total of 26,678,394 participants in the campaign. A total of 13,722,148 participants (51.4%) were female. The mean age was 46 +/- 14.1 years. Among total participants, 15,012,693 adults (56.3%) with no past history of hypertension had normal BP, 7,959,288 participants had BP in the prehypertension range (29.8%), and finally, 3,706,413 participants (13.9%) had either past medical history of hypertension, used medications, or had high BP measured in the campaign. Conclusion The campaign was feasible with the objective to increase the awareness among the public and policymakers of the importance of tackling hypertension in Iran