338 research outputs found
Flow characteristics in heated trapezoidal channels: A finite element method study of Reynolds number and fin design influences
No full textThis work investigates the effect of a number of perforated fin configurations on the convective flow characteristics within a heated trapezoidal channel. By improving the flow characteristics, pressure distribution, velocity profiles, and temperature patterns, it is intended to investigate optimum performance by using different geometrical fin designs. Numerical simulations are performed for solid and perforated fins with Reynolds numbers from 100 000 up to 200 000. Most importantly, the results highlight that perforations cause significant changes in flow behavior, such as the formation of distinct recirculation zones and dynamic pressure profile variations, which influence the thermal characteristics. This study identifies that optimization of perforated fin geometries is a key strategy to achieve high efficiency in thermal management systems for effective cooling of engineering applications
Constructing Antidictionaries in Output-Sensitive Space
No full textA word x that is absent from a word y is called minimal if all its proper factors occur in y. Given a collection of k words y_1,y_2,...,y_k over an alphabet Σ, we are asked to compute the set M^ℓ_y_1#...#y_k of minimal absent words of length at most ℓ of word y=y_1#y_2#...#y_k, #∉Σ. In data compression, this corresponds to computing the antidictionary of k documents. In bioinformatics, it corresponds to computing words that are absent from a genome of k chromosomes. This computation generally requires Ω(n) space for n=|y| using any of the plenty available O(n)-time algorithms. This is because an Ω(n)-sized text index is constructed over y which can be impractical for large n. We do the identical computation incrementally using output-sensitive space. This goal is reasonable when ||M^ℓ_y_1#...#y_N||=o(n), for all N∈[1,k]. For instance, in the human genome, n ≈ 3× 10^9 but ||M^12_y_1#...#y_k|| ≈ 10^6. We consider a constant-sized alphabet for stating our results. We show that all M^ℓ_y_1,...,M^ℓ_y_1#...#y_k can be computed in O(kn+∑^k_N=1||M^ℓ_y_1#...#y_N||) total time using O(MaxIn+MaxOut) space, where MaxIn is the length of the longest word in {y_1,...,y_k} and MaxOut={||M^ℓ_y_1#...#y_N||:N∈[1,k]}. Proof-of-concept experimental results are also provided confirming our theoretical findings and justifying our contribution
Surgical Management of Diabetic Foot Ulcers: A Tanzanian University Teaching Hospital Experience.
No full text\ud
\ud
Diabetic foot ulcers (DFUs) pose a therapeutic challenge to surgeons, especially in developing countries where health care resources are limited and the vast majority of patients present to health facilities late with advanced foot ulcers. A prospective descriptive study was done at Bugando Medical Centre from February 2008 to January 2010 to describe our experience in the surgical management of DFUs in our local environment and compare with what is known in the literature. Of the total 4238 diabetic patients seen at BMC during the period under study, 136 (3.2%) patients had DFUs. Males outnumbered females by the ratio of 1.2:1. Their mean age was 54.32 years (ranged 21-72years). Thirty-eight (27.9%) patients were newly diagnosed diabetic patients. The majority of patients (95.5%) had type 2 diabetes mellitus. The mean duration of diabetes was 8.2 years while the duration of DFUs was 18.34 weeks. Fourteen (10.3%) patients had previous history of foot ulcers and six (4.4%) patients had previous amputations. The forefoot was commonly affected in 60.3% of cases. Neuropathic ulcers were the most common type of DFUs in 57.4% of cases. Wagner's stage 4 and 5 ulcers were the most prevalent at 29.4% and 23.5% respectively. The majority of patients (72.1%) were treated surgically. Lower limb amputation was the most common surgical procedure performed in 56.7% of cases. The complication rate was (33.5%) and surgical site infection was the most common complication (18.8%). Bacterial profile revealed polymicrobial pattern and Staphylococcus aureus was the most frequent microorganism isolated. All the microorganisms isolated showed high resistance to commonly used antibiotics except for Meropenem and imipenem, which were 100% sensitive each respectively. The mean hospital stay was 36.24 ± 12.62 days (ranged 18-128 days). Mortality rate was 13.2%. Diabetic foot ulceration constitutes a major source of morbidity and mortality among patients with diabetes mellitus at Bugando Medical Centre and is the leading cause of non-traumatic lower limb amputation. A multidisciplinary team approach targeting at good glycaemic control, education on foot care and appropriate footware, control of infection and early surgical intervention is required in order to reduce the morbidity and mortality associated with DFUs. Due to polymicrobial infection and antibiotic resistance, surgical intervention must be concerned
Author Correction: A consensus protocol for functional connectivity analysis in the rat brain
No full textMutation Subsumption as Relative Incorrectness
No full textThis paper attempts to link two lines of research that have proceeded independently so far: Mutant subsumption, which is used to identify redundant mutants; and Relative correctness, which is used to define and analyze software faults. We say that a mutant M′ of a program P subsumes a mutant M of P if and only if any test datum that kills M kills M′. On the other hand, we say that a program P′ is more-correct than a program P with respect to a specification R if and only if whenever program P behaves correctly with respect to R on some input datum, so does program P′. We highlight the relationships between these two concepts and consider some potential synergies between these two research directions
Enhanced Deep Learning with Improved Feature Subspace Separation
No full textThis research proposes a new deep convolutional network architecture that improves the feature subspace separation. In training, the system considers M classes of input sets {C-i}(i=1)(M) and M deep convolutional networks {DNi}(i=1)(M) whose filter and other parameters are randomly initialized. For each input class C-i, Convolutional Neural Network generates a set of features F-i. Then, a local subspace S-i is matched for each set F-i. This is followed with a full training of the deep convolutional network DNi based on a decision criteria developed with computation of rejections of all features in {F-i}(i=1)(M) to S-i. Five different deep convolutional network topologies are used to show that the proposed technique works better for small network topologies and has comparable performance to more complex networks
Effects of Agricultural Land Use on Desert Soil Classification in Holy Karbala Governorate
No full textThis study was conducted to evaluate physical, chemical, and morphological features to classify soils at the subgroup level. The research area, located west of Karbala, consists of three locations, each comprising pedons in both cultivated and uncultivated lands. GPS coordinates were recorded, and morphological descriptions of pedon horizons were made in accordance with the American Soil Survey Manual. This study investigates the effect of agricultural land use on the classification of desert soils in the Holy Karbala Governorate. The results revealed that the dry climate caused diversity in the morphological features of the soils, mainly in horizon type, thickness, and arrangement. Agricultural usage had an impact on diagnostic horizons, particularly the gypsic horizon, and features such as soil color, structure, organic matter, carbonate minerals, gypsum, and root distribution. However, there was no substantial impact on soil texture development, and soils did not show a consistent pattern of soil separation distribution with depth, indicating weak pedogenic processes. The most common texture classes were loamy sand, sandy loam, and sand, with sand contents ranged from 902.08 to 574.12 g kg. Soil bulk density differed from 1.67 to 1.30 Mg m³, with lower values in farmed areas. Chemical properties were influenced, with soil pH ranging from 8.36 to 7.54, electrical conductivity (EC) from 5.46 to 2.03 dS m, cation exchange capacity (CEC) from 15.25 to 2.05 meq.100g, organic matter from 43.51 to 1.18 g kg, carbonate minerals from 461.18 to 174.06 g kg, and calcium sulfate from 182 to 21 g kg. The soils were classed as Aridisols because they were found in a dry desert with an Aridic moisture regime. The presence of distinctive saline layers such as Calcic and Gypsic was discovered, resulting in the classification of cultivated soils as Typic Haplocalcids and uncultivated lands as Typic Calcigypsids
POLYMERIZATION OF STYRENE USING ZIEGLER – NATTA CATALYST TYPE TICL4/MGCL2 – EB /ALET3
No full textIn this study Ziegler – Natta catalyst was prepared which is a multi component catalytic system composed of, titaniumtetrachloride (TiCl4) as a active material, anhydrous magnesium chloride MgCl2 as support (carrier) which distribute the active material, ethyl benzoate EB as electron donor compound, and triethylaluminum (AlEt3) as co-catalyst ( promoter ). This catalyst used to product stereoregular polystyrene with high percent of isotactic isomer. The effect of triethylaluminum concentration on polymer yield was also studied and found that optimum concentration of AlEt3 in the polymerization mixture is 0.257 M, The kinetic study showed that the rate of polymerization decay with time because of decrease in catalyst activity. The values of isotacticity index showed that the isotacticity decrease with increase triethylaluminum concentratio
Nerve sheath tumor with degenerative atypia and multivacuolated lipoblasts
No full textLipoblastic nerve sheath tumor is a recently described benign soft tissue tumor consisting of lipoblasts in a neural-schwannian background. The 6 reported cases have exclusively comprised signet ring lipoblasts and showed no cellular atypia. The authors describe the first lipoblastic nerve sheath tumor to harbor multivacuolated lipoblasts and degenerative atypia, underscoring its important differential diagnosis with well-differentiated liposarcoma. The purpose of this report is to expand the morphologic spectrum of this unusual neoplasm, and reemphasize the potential of benign nonadipocytic tumors to harbor multivacuolated lipoblasts and mimic liposarcoma. © 2012 The Author(s).Ayad T, 2007, EUR ARCH OTO-RHINO-L, V264, P93, DOI 10.1007-s00405-006-0119-6; Ceballos KM, 1999, ARCH PATHOL LAB MED, V123, P941; Chen E, 2010, AM J SURG PATHOL, V34, P707, DOI 10.1097-PAS.0b013e3181d74bdb; Coffin CM, 2009, AM J SURG PATHOL, V33, P1705, DOI 10.1097-PAS.0b013e3181b76462; Dei Tos Angelo P., 1994, American Journal of Surgical Pathology, V18, P913, DOI 10.1097-00000478-199409000-00006; Fukunaga M, 1998, PATHOL INT, V48, P562, DOI 10.1111-j.1440-1827.1998.tb03950.x; Hornick JL, 2004, AM J SURG PATHOL, V28, P1257, DOI 10.1097-01.pas.0000135524.73447.4a; Khalifa MA, 2000, AM J CLIN PATHOL, V114, P123; Lae ME, 2002, HISTOPATHOLOGY, V40, P505, DOI 10.1046-j.1365-2559.2002.01409.x; Mentzel T, 2010, MODERN PATHOL, V23, P729, DOI 10.1038-modpathol.2010.66; Plaza JA, 2006, AM J SURG PATHOL, V30, P337; Vecchio G M, 2010, Pathologica, V102, P108; Weiss SW, 2008, ENZINGER WEISSS SOFT; Weiss S W, 1996, Monogr Pathol, V38, P2070
- …
