360 research outputs found
Adaptive congestion control in networks with multiple congested nodes
No full textIn this paper, an analytical method for a design of a congestion control scheme in packet switching network is presented This scheme is particularly suitable for implementation in ATM Switch Systems, for the support of the available bit rate (ABR) service in ATM networks The control method is rate based with a local feedback controller associated with each switch node. The controller is a generalization of the standard proportional-plus-derivative controller, with the difference that extra higher order derivative terms are involved to accommodate for delay in networks. It is shown that there exist a set of control gain that result in applying asymptotic stability of the linearized network model. The use of adaptive control for finding the state feedback gains for asymptotically stability is our main purposes. Since the proposed approach considers the case of multiple congested nodes, it stabilizes the entire links in the network
Preserving Urmia Lake in a changing world : reconciling anthropogenic and climate drivers by hydrological modelling and policy assessment
No full textUrmia Lake, in north-western Iran, is an important internationally recognized natural area designated as a RAMSAR site and UNESCO Biosphere Reserve. Over the last 20 years, the surface area of Urmia Lake has declined by 80%. As a result, the salinity of the lake has sharply increased which is disturbing the ecosystems, local agriculture and livelihoods, regional health, as well as tourism, which could amplify economic, political and ethnic tensions in this already volatile region. In response to that, Iranian government established the ten-year “Urmia Lake Restoration Program (ULRP)” proposing six approaches in terms of controlling, protecting, surveying, studying and supplying water from other sources. This study first assessed the main reasons for the decreased inflow using the Variable Infiltration Capacity (VIC) hydrological model, including reservoirs and irrigation modules. The results showed that climate change was the main contributor to this inflow reduction. However, water resources development, particularly water use for irrigation, has played a substantial role as well. In the second step assessed Urmia lake inflow under future climate change and irrigation scenarios. Then, the (VIC) model was forced with bias-corrected climate model outputs for both the lowest (RCP2.6) and highest (RCP8.5) greenhouse-gas concentration scenarios to estimate future water availability. The results showed that the water resources plans are not robust to changes in climate. In other words, if future climate change is limited due to rapid mitigation measures (RCP2.6) the new strategy of reduction of irrigation water use can contribute to preserve Urmia Lake. The next step of this study assessed the quantitative impacts of ULRP by introducing a constructive framework. The framework depicts real water saving by distinguishing between water withdrawals, depletion, and demand in the context of uncertainties in future demand and supply. The results showed that although the ULRP helps to increase inflow by up to 57% it is unlikely to fully reach its target for three main reasons. The first reason is decreasing return flows due to increasing irrigation efficiency. The second reason is increased depletion which is due to neglecting the fact that agricultural water demand is currently higher than available water for agriculture. The third reason is ignoring the potential impact of climate change. However, there still can be some additional none-quantifiable barriers and challenges that may cause the failure of the restoration plan. Therefore, in the last step, this study used two types of qualitative data to explore these aspects: first, the opinions from 40 experts and the in-situ observation of some of the ULRP implementation practices. The results indicate a number of challenges for the ULRP implementation including the water use regulations and the agricultural measures. In addition, (water) demand-side measures such as crop pattern changes were more supported, as opposed to supply-side measures. This thesis showed that the sustainable approach to preserve Urmia Lake should incorporate both demand management (considering socioeconomic complexity) and flexible supply management strategies (to deal with uncertainties in climate variability and change) in a participatory approach. To be prepared for the future, also scenarios with reduced inflow into Urmia Lake, either due to climate change or water resources development, need to be considered to deal with considerable amounts of variability in the current system and with future changes in climate and socioeconomic conditions.</p
Efficacy and Safety of Single Low Dose Intravenous Fentanyl in Pain Reduction of Lumbar Puncture in Near Term Neonates by A Randomized Clinical Trial
No full textHow to Cite This Article: Fallah R, Habibian S, Noori-Shadkam M. Efficacy and Safety of Single Low Dose Intravenous Fentanyl in Pain Reduction of Lumbar Puncture in Near Term Neonates by A Randomized Clinical Trial. Iran J Child Neurol. Spring 2016; 10(2):60-66.AbstractObjectiveReduction of pain of invasive procedures in neonates can prevent pain side effects. The purpose of present study was to evaluate the efficacy and safety of a single low dose of intravenous fentanyl in reducing of lumbar puncture (LP) pain in neonates.Materials & MethodsIn this randomized clinical trial, registered with code number of 2014022616761N150, admitted neonates to Shahid Sadoughi Hospital, Yazd, Iran from August-April 2012 (45 cases) were randomly assigned into two groups to receive 2 μg/kg of intravenous fentanyl or 0.2 milliliter of normal saline, two min before LP. Primary outcome was success rate in reducing of pain during needle insertion to skin (pain score of less than three). Secondary outcomes were clinical side effects and serious adverse events.ResultsForty-five neonates including 23 girls and 22 boys were evaluated. Pain reduction was obtained in 39.1% (9 of 23 neonates) of fentanyl group and in 4.5% (one of 22 neonates) of control group. Means of pulse rate (136.41± 9.16 vs. 148.9± 8.99) and pain score during needle insertion (3.41±1.31 vs. 5.8±1.12) were lower in fentanyl group. No severe adverse effects were seen in both groups. Side effects such as vomiting [9% (N=2) in control and 4.3% (N=1) in fentanyle group] and mild transient decrease in oxygen saturation in 8.7% (N=2) of fentanyle group were seen. Safety in two groups was not statistically different.ConclusionIntravenous fentanyl might be considered as a safe and effective analgesic drug in LP in neonates.ReferencesLehman RL, Schor NF. Special Diagnostic Procedures. In: Kliegman RM, Stanton BF, Schor NF, St. GemeJW, Behrman RE. Nelson Textbook of Pediatrics. Philadelphia, Saunders 2011; 19th edition, Pp: 2013-2017.Sacchetti A, Baren J, Carraccio C. Total procedural requirements as indication for emergency department sedation. Pediatr Emerg Care 2010;26(3):209-11.Leroy PL, Gorzeman MP, Sury MR. Procedural sedation and analgesia in children by non-anesthesiologists in an emergency department. Minerva Pediatr 2009;61(2):193-215.Gorchynski J, McLaughlin T. The routine utilization of procedural pain management for pediatric lumbar punctures: are we there yet? J Clin Med Res 2011 June 26;3(4):164-7.Maurizi P, Russo I, Rizzo D, Chiaretti A, Coccia P, Attinà G, Ruggiero A, Riccardi R. Safe lumbar puncture under analgo-sedation in children with acute lymphoblastic leukemia. Int J Clin Oncol 2014;19(1):173-7.Pedersen RS, Bayat A, Steen NP, Jacobsson ML.Nitrous oxide provides safe and effective analgesia for minor paediatric procedures--a systematic review. Dan Med J 2013;60(6): A4627.Derakhshanfar H, Modanlookordi M, Amini A, Shahrami A. A comparative study of the sedative effect of oral midazolam and oral promethazine medication in lumbar puncture. Iran J Child Neurol 2013;7(2):11-6.Anghelescu DL, Burgoyne LL, Faughnan LG, Hankins GM, Smeltzer MP, Pui CH. Prospective randomized crossover evaluation of three anesthetic regimens for painful procedures in children with cancer. J Pediatr 2013;162(1):137-41.Fein D, Avner JR, Khine H. Pattern of pain management during lumbar puncture in children. Pediatr Emerg Care. 2010;26(5):357-60.Anand KJ1, Aranda JV, Berde CB, Buckman S, Capparelli EV, Carlo W, Hummel P, Johnston CC, Lantos J, Tutag-Lehr V, Lynn AM, Maxwell LG, Oberlander TF, Raju TN, Soriano SG, Taddio A, Walco GA. Summary proceedings from the neonatal pain-control group. Pediatrics 2006; 117(3 Pt 2):S9-S22.Grunau RE, Holsti L, Haley DW, Oberlander T, Weinberg J, Solimano A, Whitfield MF, Fitzgerald C, Yu W. Neonatal procedural pain exposure predicts lower cortisol and behavioral reactivity in preterm infants in the NICU. Pain 2005; 113(3):293-300.American Academy of Pediatrics Committee on Fetus and Newborn; American Academy of Pediatrics Section on Surgery; Canadian Paediatric Society Fetusand Newborn Committee, Batton DG, Barrington KJ, Wallman C. Prevention and management of pain in the neonate: an update. Pediatrics 2006;118(5):2231-41.Schmidt B, Adelmann C, Stützer H, Welzing L, Hünseler C, Kribs A, Roth B. Comparison of sufentanil versus fentanyl in ventilated term neonates. Klin Padiatr 2010;222(2):62-6.Anand KJ, Willson DF, Berger J, Harrison R, Meert KL, Zimmerman J, et al. Tolerance and withdrawal from prolonged opioid use in critically ill children. Pediatrics 2010;125(5): e1208-25.Lawrence J, Alcock D, McGrath P, Kay J, MacMurray SB, Dulberg C. The development of a tool to assess neonatal pain. Neonatal Netw 1993 ;12(6):59-66.Pedersen RS, Bayat A, Steen NP, Jacobsson ML.Nitrous oxide provides safe and effective analgesia for minor paediatric procedures--a systematic review. Dan Med J 2013; 60(6):A4627.Lago P, Guadagni A, Merazzi D, Ancora G, Bellieni CV, Cavazza A; Pain Study Group of the Italian Society of Neonatology. Pain management in the neonatal intensive care unit: a national survey in Italy. Paediatr Anaesth 2005; 15(11):925-31.Glatstein MM, Zucker-Toledano M, Arik A, Scolnik D, Oren A, Reif S.Incidence of traumatic lumbar puncture: experience of a large, tertiary care pediatric hospital. Clin Pediatr (Phila) 2011;50(11):1005-9.Roberts KD, Leone TA, Edwards WH, Rich WD, Finer NN. Premedication for nonemergent neonatal intubations: a randomized, controlled trial comparing atropine and fentanyl to atropine, fentanyl, and mivacurium. Pediatrics 2006; 118(4):1583-91.Ancora G, Lago P, Garetti E, Pirelli A, Merazzi D, Mastrocola M, Pierantoni L, Faldella G Efficacy and safety of continuous infusion of fentanyl for pain control in preterm newborns on mechanical ventilation. J Pediatr 2013;163(3):645-51.e1.Zier JL, Doescher JS. Seizures temporally associated with nitrous oxide administration for pediatric procedural sedation. J Child Neurol 2010;25(12):1517-20.Anghelescu DL, Burgoyne LL, Faughnan LG, Hankins GM, Smeltzer MP, Pui CH. Prospective randomized crossover evaluation of three anesthetic regimens for painful procedures in children with cancer. J Pediatr 2013;162(1):137-41.Mantadakis E, Katzilakis N, Foundoulaki E, Kalmanti M. Moderate intravenous sedation with fentanyl and midazolam for invasive procedures in children with acute lymphoblastic leukemia. J Pediatr Oncol Nurs 2009;26(4):217-22.Gitto E, Pellegrino S, Manfrida M, Aversa S, Trimarchi G, Barberi I, Reiter RJ. Stress response and procedural pain in the preterm newborn: the role of pharmacological and non-pharmacological treatments. Eur J Pediatr 2012;171(6):927-33.Mireskandari SM, Abulahrar N, Darabi ME, Rahimi I, Haji-Mohamadi F, Movafegh A. Comparison of the effect of fentanyl, sufentanil, alfentanil and remifentanil on cardiovascular response to tracheal intubation in children. Iran J Pediatr 2011; 21(2):173-80.Nouri shadkam M, Lotfi M.H. Effect of low dose venous fentanyl in reducing the pain of lumbar puncture in infants. Acta Medica Iranica 2007; 45(3);189-192.Dewhirst E, Naguib A, Tobias JD. Chest wall rigidity in two infants after low-dose fentanyl administration. Pediatr Emerg Care 2012 ;28(5):465-8.
Occurrence and description of Dactylogyrus sphyrna Linstow, 1878 (Monogenea: Dactylogyride) on the gills of an Iranian endemic fish Leucisucs persidis Coad, 1981 as a new host
No full textLeuciscus persidis as Iranian endemic fish in Kaftar lake and its headwaters (Mesopotamian subregion, Kor-Neiriz basin and Shadkam river) has been infected with a species of Dactylogyrus sphyrna. Comparison of collected parasites with Euro-Asian subregion showed that the similarity of them is more than their differences, although a little difference between them was observed. In this paper also introduce of Dactylogyrus sphyrna parasite to the new host is discussed
Occurrence and description of Dactylogyrus sphyrna Linstow, 1878 (Monogenea: Dactylogyride) on the gills of an Iranian endemic fish Leucisucs persidis Coad, 1981 as a new host
No full textLeuciscus persidis as Iranian endemic fish in Kaftar lake and its headwaters (Mesopotamian subregion, Kor-Neiriz basin and Shadkam river) has been infected with a species of Dactylogyrus sphyrna. Comparison of collected parasites with Euro-Asian subregion showed that the similarity of them is more than their differences, although a little difference between them was observed. In this paper also introduce of Dactylogyrus sphyrna parasite to the new host is discussed
A study on the coupled effects of solute and grain size on the work hardening of fine- grained FCC alloys
No full textThis thesis develops a physically based model for the work hardening of model (pure or solute strengthened) FCC alloys having grain sizes of between 2 μm and 100 μm. This model builds on a previous study of Sinclair et al. (2006) on fine-grained pure Cu and extends it to Cu16at%Ni, Cu50at%Ni and Cu1.5at%Al alloys. Through careful and systematic mechanical testing coupled with microstructural observations several basic hypotheses were tested. The yielding behaviour of fine-grained materials showed an extension of the elasto-plastic transition (over the generally accepted 0.002 offset strain) with decreasing grain size and increasing solute content. This resulted in Hall-Petch plots which showed that the grain size effect was more pronounced with increasing solute content. In all of the materials tested with a sufficiently fine grain size, the stress-strain plots showed an inflection (i.e. region of a low work hardening or “plateau”). While the work hardening rate dropped significantly in this portion of the test, image correlation was used to show that the drop in work hardening was not sufficient to cause strain localization. The stress-strain plots were differentiated and work hardening behaviour was analyzed using a Kocks-Mecking model. An important observation was that with increasing solute content from pure Cu to Cu50at%Ni, a grain size dependent separation between the work hardening plots appeared for tests performed at room temperature. This observation was initially hypothesized to be due to backstresses as proposed in the original model of Sinclair (Sinclair et al. 2006). This idea was tested using strain-rate sensitivity experiments. Strain-rate sensitivity tests showed that a single mechanism (forest hardening) controls the work hardening behaviour beyond the initial few percentage of straining. To unify all these experimental observations in a self-consistent work hardening model, the original Sinclair model was modified through the addition of a new variable, n*f , which accounts for additional dislocation storage by the forest dislocations blocked at grain boundaries. It was hypothesized that the effects of dislocation/grain boundary interactions on screening/annihilation of dislocations could be used to capture the initial high rate sensitivity at the “plateau” in the stress-strain curve of fine grained alloys.Applied Science, Faculty ofMaterials Engineering, Department ofGraduat
A Study of Homogenization and Precipitation Hardening Behaviour of Mg-Ca-Zn Alloys
No full textMicrostructural evolution during heat treatment and the precipitation hardening response of Mg-Ca-Zn alloys were investigated. The binary Mg-2.5Ca alloy was chosen as the base alloy and the effects of adding one and two wt% zinc on the microstructural characteristics and precipitation hardening of the alloy system were studied. The as-cast microstructure of all three alloys showed dendritic solidification of α-Mg and the formation of the eutectic mixtures and/or multiple phases within the interdendritic regions. Homogenization heat treatment of the binary alloy removed the dendritic structure of α-Mg and spherodized the lamellar eutectic of α-Mg+Mg2Ca. Homogenization heat treatment in the ternary Mg-Ca-Zn alloys resulted in the formation of α-Mg grains with Mg2Ca and zinc-containing particles mainly dispersed along the grain boundaries. The EDS analysis suggested that zinc is incorporated in Mg2Ca particles. To study the precipitation hardening response of the alloys, homogenized alloys were aged at 175°C, 200°C and 220°C. At all three isothermal aging temperatures, the binary alloy showed only a slight increase in hardness, i.e. from 50 VHN in the homogenized state to approximately 53 VHN when peak aged. On the other hand, adding zinc was found to promote the age hardening response of the ternary alloys and caused the hardness to increase up to 70 VHN at the peak-aged condition. To further study the precipitation hardening behavior of the alloys, DSC and IC studies were conducted on the homogenized, as–quenched, alloys. The DSC result of the binary alloy showed only one exothermic heat effect, while the ternary alloys showed multiple exothermic peaks. Analysis of the DSC and IC traces, along with the evaluation of the slight increase in microhardness, suggested that non-coherent equilibrium precipitates formed in the aged binary alloy. In addition, it was suggested that the formation of coherent precipitates during aging can be the cause of the pronounced increase in hardness in the aged ternary alloys. The IC traces of the alloys were used to evaluate the kinetics of precipitation in the ternary alloys. It was concluded that increasing aging temperature from 175°C to 220°C greatly increased the precipitation rate. Finally the JMAK model was fit to the experimentally analyzed data for the evolution of the relative volume fraction of precipitates. It was found that the experimentally analyzed data was reasonably well described by the JMAK model. The corresponding JMAK kinetic parameters k and n were relatively close for the two ternary alloys at any aging temperature. The temperature dependence of k was modeled using the Arrhenius-type rate relationship. This analysis resulted in a smaller value for the apparent activation energy in the ternary alloy containing the higher zinc level, i.e. in Mg-2Ca-2Zn alloy
Reclaiming the Urban Public Realm as a Site for Children’s Play
No full textSince the earliest waves of Modernist planning and the application of systematic zoning, parks and playgrounds have served as exclusive domains for children's recreational activities within the rational city. However, with the prevalence of car-dependent lifestyles, free outdoor play has nearly vanished from urban public realms. The increasing rates of childhood obesity worldwide, along with alarming risks to mental and physical health, underscore the urgent need to reevaluate the childless urban landscape. This dissertation challenges this phenomenon by recognizing the developmental significance of children's engagement in urban life, aiming to reassert the urban public realm as a vital site for children's play and agency.
Despite numerous studies advocating for the promotion of outdoor free play and exploring opportunities for children’s independent mobility, a persistent gap remains between research and practical urban policies. Grounded in the UN's Child-Friendly Cities Initiative, this research aims to bridge this divide by drawing on empirical data grounded in the lived experiences of children and emphasizing the reactivation of public spaces for play while promoting intergenerational coexistence.
Informed by relativist ontology, constructivist epistemology, and the communicative turn in planning theory, three key objectives underpin the investigation: to examine how urban configurations impact children's active play; to identify the types of play happening on pathways connecting residential areas to schools and play spaces; and, to explore the linkages between neighbourhood configurations, children's sense of belonging, and perceptions of safety. This research employs critical ethnography and draws on empirical data grounded in the lived experiences of children to address these objectives.
The findings advocate for urban planners to pay equal attention to the quality and configuration of urban pathways alongside parks and playgrounds, emphasizing the urban public realm as a play network and leveraging local knowledge and children's lived experiences to create inclusive, playful, and vibrant urban environments. Moreover, it holds added relevance in the context of the COVID-19 pandemic, offering insights into the impact of crises on public space usage. This research contributes to the broader planning discourse by opening new possibilities for reuniting families with children in the urban metropolitan core and achieving greater social and environmental sustainability goals
Preserving Urmia Lake in a changing world : reconciling anthropogenic and climate drivers by hydrological modelling and policy assessment
No full textA new hybrid method DSM for parameter setting of meta-heuristic algorithms
No full textParameters of meta-heuristic algorithms are very effective in their performance and are usually done experimentally, which is very time-consuming. In this research, a hybrid method for selecting the optimal parameters of meta-heuristic algorithms is presented. The proposed method is a combination of data envelopment analysis methods and response surface methodology and is called DSM. In fact, this method can be used to optimize multi-objective problems and its main advantage is to create and optimize one performance response procedure instead of optimizing multiple output response procedures. In addition to optimizing parameters, it also simultaneously maximizes efficiency. In this research, the proposed DSM method has been used to adjust the parameters of the cuckoo optimization algorithm to optimize the standard and experimental Aklay and Rastrigin functions. In the hybrid DSM method, first, the efficiency value is calculated using data envelopment analysis for each set of meta-heuristic algorithm parameters, then the response procedure for performance is determined according to the meta-heuristic algorithm parameters using the response surface methodology. Finally, by optimizing the efficiency surface, the optimal values of the cuckoo algorithm parameters are obtained. In order to validate, the results of the proposed method have been compared with a similar method. The results show better performance of the hybrid algorithm in terms of solution time, number of iterations, and accuracy of the optimization function compared to other similar methods
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