197 research outputs found
Square-Root Finding Problem In Graphs, A Complete Dichotomy Theorem
Graph G is the square of graph H if two vertices x,y have an edge in G if and
only if x,y are of distance at most two in H. Given H it is easy to compute its
square H^2. Determining if a given graph G is the square of some graph is not
easy in general. Motwani and Sudan proved that it is NP-complete to determine
if a given graph G is the square of some graph. The graph introduced in their
reduction is a graph that contains many triangles and is relatively dense.
Farzad et al. proved the NP-completeness for finding a square root for girth 4
while they gave a polynomial time algorithm for computing a square root of
girth at least six. Adamaszek and Adamaszek proved that if a graph has a square
root of girth six then this square root is unique up to isomorphism. In this
paper we consider the characterization and recognition problem of graphs that
are square of graphs of girth at least five. We introduce a family of graphs
with exponentially many non-isomorphic square roots, and as the main result of
this paper we prove that the square root finding problem is NP-complete for
square roots of girth five. This proof is providing the complete dichotomy
theorem for square root problem in terms of the girth of the square roots
Информационно-психологическое воздействие на выбор покупателей
В статье рассматривается свойство информации воздействовать на поведение и выбор потребителя, рассмотрены основные методы манипуляции потребительским выбором. Обсуждаются такие феномены как эффект заражения, маркетинговое паразитирование, создание якорей сознания, стереотипов выбора. Сделан вывод об эмоциональной природе дополнительной ценности товара, приобретаемого в результате психологической манипуляции потребителем
Evaluation of Iron Status in 9-Month to 5-Year-Old Children with Febrile Seizures: A Case-Control Study in the South West of Iran
ObjectiveFebrile convulsions are prevalent in children aged between 9 months and 5 years, with an incidence of 2-5%. On the other hand, iron deficiency anemia is the most common hematologic disease of infancy and childhood with a period of incidence that coincides with the time of developing febrile convulsions.Therefore, it is hypothesized that there is a possible association between these conditions. This study was designed to elucidate this association.Materials & MethodsTwo sex and age matched groups (n=50 in each) of 9-month to 5-year-old febrile children who were admitted to Abuzar Hospital between September 2003 and October 2004 were selected. The first group, or the case group, included children with the first attack of febrile seizure and the second group, or the control group, included febrile children without seizure. Blood samples were collected for measuring complete blood count (CBC) indices, serum Iron,ferritin and total iron binding capacity (TIBC) levels.ResultsBoth groups were comparable for age, sex, and the type of febrile illness at admission, except for seizure. There was no significant difference in CBC, Iron and TIBC between two groups but a signicant difference was seen in MCV (Mean Corpuscular Volume), especially in females (P= 0.017). The ferritin level in the case group was significantly lower (30.3 ±16.5 µg/dl) than the control group (84.2 ±28.5 µg /dl) (P= 0.000).ConclusionThe findings of this study suggested a positive association between iron deficiency and the first febrile seizure in children. Supplemental iron may prevent the recurrence of febrile seizure. Prudently, further studies with larger sample sizes and longer follow-up periods need to be undertaken to substantiate this hypothesis.
Vpliv zaobljenosti delcev in morfologije na strižni porušni mehanizem zrnatih zemljin pod pasovnimi temelji
This study investigates the effect of particles roundness and morphology on the shear failure mechanism of soil. A strip footing was modeled under laboratory conditions. Calcareous soil was tested with three roundness classes: angular, rounded and well-rounded shapes with sizes of 0.30 mm to 4.75 mm. These were divided into six different groups at three relative densities of 30%, 50% and 70%. A series of photographs was taken during the tests and analyzed using the particle image velocimetry (PIV) method to understand the soil-deformation mechanism. The results showed that increasing the sample sizes increased the affected area of the soil. At the same time, increasing the relative density caused a punching failure mechanism that went towards the general failure. The shear failure mechanism of the soil changed from general toward punching shear failure with increasing particle roundness. This effect was larger with the smaller materials. Underneath the affected layers of soil, the angular samples were deeper than the rounded and well-rounded samples. The affected depth in the angular soil was approximately 1.5B in the smallest size group. This was more than 3B and near 4B in the largest size group. Both the sides and the underlying soil layers should be considered on angular soils. The area under the footing becomes more important than the side parts after increasing the roundness of the particles.V članku je raziskovan učinek zaobljenosti delcev in morfologije na strižni porušni mehanizem zrnate zemljine. Pasovni temelj je bil modeliran v laboratorijskih pogojih. Apnenčasta zemljina je bila preizkušena s tremi razredi zaobljenosti zrn: koničasta, zaobljena in dobro zaobljena zrna z velikostmi od 0,30 mm do 4,75 mm. Ti so bili razdeljeni v šest različnih skupin pri treh relativnih gostotah 30 %, 50 % in 70 %. Da bi razumeli mehanizem deformacije zrnate zemljine je bila med preizkusi narejena vrsta fotografij in izvedena analiza z metodo slik sledilnih delcev (PIV). Rezultati so pokazali, da je povečanje velikosti vzorcev povečalo prizadeto območje zemljine. Hkrati pa je povečanje relativne gostote povzročilo prebodni porušitveni mehanizem, ki je prešel proti splošni porušitvi. Mehanizem strižne porušitve zemljine se je spremenil iz splošnega v prebodni porušitveni mehanizem z večanjem zaobljenosti delcev. Ta učinek je bil večji pri manjših drobnejših materialih. Vplivno območje je segalo globlje pri vzorcih s koničastimi zrni kot pri vzorcih z zaobljenimi in dobro zaobljenimi zrni. Ugotovljena globina v zemljini s koničastimi zrni je bila približno 1,5B v najmanjši velikostni skupini medtem, ko je bila več kot 3B in blizu 4B v skupini z največo velikostjo zrn. V zemljinah s koničastimi zrni je treba upoštevati stranske sloje in spodnje sloje zemljin. Območje pod temelji postane pomembnejše od stranskih delov s povečanjem zaobljenosti delcev
Silica Chloride Nano Particle Catalyzed Synthesis of 2,2\u27-(arylmethylene)bis(5,5-dimethylcyclohexane-1,3-dione) Derivatives
Silica chloride nano particle (nano SiO2–Cl), has been found to be heterogeneous catalyst for fa-cile and simple condensation of dimedone with aromatic aldehydes into 2,2\u27-(arylmethylene)bis(5,5-dimethylcyclohexane-1,3-dione) derivatives in dry CH2Cl2. (doi: 10.5562/cca1721
The Relationship between Osteogenesis Imperfecta and Spinal Muscular Atrophy
ObjectiveA 4-month-old female with osteogenesis imperfecta (OI) type II was admitted in PICU of our center due to severe respiratory distress and fever with a diagnosis of severe pneumonia, and mechanical ventilation was initiated. Due to severe hypotonia, NCV and EMG were performed, and spinal muscular atrophy (SMA) type I was diagnosed.Keywords: Osteogenesis imperfecta; spinal muscular atrophy; hypotoni
The Accuracy of Ultrasonography in Detection of Ulnar Collateral Ligament of Thumb Injuries; a Cross-Sectional Study
Introduction: Timely diagnosis and treatment of traumatic injury to ulnar collateral ligament (UCL) of thumb is of special importance for preserving the full function of the hand. Therefore, the present study has been designed with the aim of evaluating the accuracy of ultrasonography in detection of these injuries. Methods: The present diagnostic accuracy study was performed on traumapatients over 15 years oldwho had clinical evidence of injury to UCL of thumb and were admitted to the emergency department. All patients were evaluated regarding injury to the mentioned ligament via ultrasonography and MRI and finally, the accuracy of ultrasonography in this regard was measured considering MRI as the reference test. Results: 20 individuals with the mean age of 38.60 § 13.45 (16 – 64) years were evaluated (60% male). Based on ultrasonography andMRI findings 7 (35%) individuals and 7 (35%), respectively had complete ligament rupture (kappa: 0.560 (95% CI: 0.179 – 0.942)). Sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio of ultrasonography in detecting injuries of the mentioned ligament were 71.42 (30.25 – 94.88), 84.61 (53.66 – 97.28), 71.42 (30.25 – 94.88), 84.61 (53.66 – 97.28), 2.5 (0.71 – 8.82), and 0.18 (0.04 – 0.67), respectively. Conclusion: Based on the findings of the present study, performance of ultrasonography by a radiologist in the emergency department has 80% accuracy in detecting traumatic injuries of UCL of the thumb
Modelling of waste heat recovery of a biomass combustion plant through ground source heat pumps- development of an efficient numerical framework
Development of a reliable and convenient dynamic modelling approach for ground source heat pumps remains as an important unresolved issue. As a remedy, in this work a novel, computationally-efficient modelling framework is developed and rigorously validated. This is based upon an implicit computational modelling approach of the ground together with an empirical modelling of heat and fluid flow inside U-tube ground heat exchangers and waste heat calculations. The coupled governing equations are solved simultaneously and the influences of parameters on the performance of the whole system are evaluated. The outcomes of the developed framework are, first, favorably compared against two different existing cases in the literature. Subsequently, the underground storage and recovery process of the waste heat through flue gases generated by a biomass combustion plant are modelled numerically. This reveals the history of temperature distributions in the ground under different configurations of the system. The results show that for a biomass combustion plant generating flue gases at 485.9 K as waste heat with the mass flow rate of 0.773 kg/s, the extracted heat from the ground is increase by 7.6%, 14.4% and 23.7% per unit length of the borehole corresponding to 40 °C, 50 °C and 60 °C storage temperatures. It is further shown that the proposed storage system can recover a significant fraction of the thermal energy otherwise wasted to the atmosphere. Hence, it practically offers a sizable reduction in greenhouse gas emissions
Predicting Factors for the Communication between hydatid Cyst and Biliary Tract
Background: Hydatid cyst communicated with biliary tract increases the morbidity and mortality rates. Therefore, early detection and treatment are vital.Methods: From 96 patients undergone hydatid cyst surgery, 12 were excluded. The specifications, size, location, and position of the cyst, the condition of the cyst wall thickness, the caught lobe, cyst rupture, liver abscess, and the size of the inside and outside liver bile ducts were identified through computed tomography scanning. Age, gender, icterus, white blood cell (WBC) count, the total, direct, and indirect bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase were identified.Results: In 21 patients (13 men and 8 women), there was communication between the hydatid cyst and biliary tract; from them, 14 patients had icterus. There were significant differences between the size of the cyst, the levels of liver enzymes, bilirubin, and alkaline phosphatase, and WBC count in communicated and non-communicated hydatid cysts (P = 0.001). There were no significant differences between the two groups in terms of age, gender, location of the cysts in the liver, and the thickness of the liver.Conclusions: Only the cyst size and the level of bilirubin were the predicting factor for the communication between hydatid cyst and biliary tract
PROJETO GENERATIVO E OTIMIZAÇÃO DE DESEMPENHO IEQ DE EDIFÍCIOS ESCOLARES COM BASE EM UM ALGORITMO PARAMÉTRICO
This research aims to examine the potential of generative and optimization algorithms in the early stage of a school building design in Tabriz to achieve better IEQ. It also investigates the compatibility of the evolutionary optimization tools combined with a parametric model in stimulating building comfort performance in achieving an optimized design. This process includes four steps: defining the parametric building model, defining its material and construction properties, stimulation of thermal and visual comfort and carbon dioxide concentration, optimization, and choosing the best result. The adaptive PMV model is used for thermal comfort, imageless daylight glare probability is used for visual comfort, and a CO2 concentration is used for IAQ assessment. It was found that the performance of the options introduced by the algorithm is more appropriate than the design prototype. However, the results show that the samples are acceptable in carbon dioxide concentration. What needs further investigation is thermal and visual comfort. Among the studied variables on IEQ performance, the WWR ratio of the southern wall had the most significant impact. Based on the optimization results, thermal comfort changed in the range of 10%, visual comfort in the range of 30%, and CO2 concentration in the range of 0.19%.Esta pesquisa tem como objetivo examinar os potenciais de algoritmos generativos e de otimização na fase inicial de um projeto de edifício escolar em Tabriz para obter um melhor IEQ. Também investiga a compatibilidade das ferramentas de otimização evolutiva combinadas com um modelo paramétrico para estimular o desempenho de conforto de construção na obtenção de um design otimizado. Este processo inclui quatro etapas: definição do modelo paramétrico de construção, definição de suas propriedades materiais e construtivas, estimulação do conforto térmico e visual e da concentração de dióxido de carbono, otimização e escolha do melhor resultado. O modelo adaptativo PMV é usado para conforto térmico, a probabilidade de ofuscamento da luz do dia sem imagens é usada para conforto visual, uma concentração de CO2 é usada para avaliação de IAQ. A investigação revelou que o desempenho das opções introduzidas pelo algoritmo é mais adequado do que o protótipo de projecto. No entanto, os resultados mostram que as amostras são aceitáveis na concentração de dióxido de carbono. É necessário mais investigação para conforto térmico e visual. Dentre as variáveis estudadas sobre o desempenho do IEQ, a relação WWR da parede sul teve o impacto mais significativo. Com base nos resultados da otimização, o conforto térmico mudou na faixa de 10%, o conforto visual na faixa de 30% e a concentração de CO2 na faixa de 0,19%
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