187 research outputs found
Can the "Strength of Connections" Account Explain Picture and Word Naming and Categorization Data?
Potter and Faulconer (1975) reported that participants were faster to read words aloud than they were to name pictures, but were faster to categorize pictures than words. They took this as falsification of an account in which picture representations have to be translated to their verbal counterparts before semantic information about the object could be activated, and corroboration of an account that claimed that both picture and verbal representations have direct access to semantics. Their direct access account does sufficiently explain the findings, but there are other plausible accounts that could better explain the specific pattern they found. In the present work, I sought to explain their findings using an alternative account proposed by Besner et al. (2011), which posits that the strength of connections between localist modules vary as a function of use. Besner et al. (2011) found that participants were faster to perform parity judgments on Arabic numerals than on number words, but were equally fast at reading/naming aloud both, a finding that cannot be explained by the received view that frequency effects exist as resting levels of activation in localist modules, but can be explained by the strength of connections (SOC) account. The present experiments replicate Potter and Faulconer’s (1975) findings, and also replicate findings by Rogers and Monsell (1995) that show that switching from one task to the other incurs an RT cost. I derived and predicted that these switch costs would be larger in blocks in which the task instructions conflict with the task participants have learned to associate with a stimulus (default set), than in blocks in which task instructions are compatible with the default set. I find data in support of this prediction for words, but not for pictures. Possible reasons for the failure to find the predicted pattern for pictures are briefly discussed
Low Complexity V-BLAST MIMO-OFDM Detector by Successive Iterations Reduction
V-BLAST detection method suffers large computational complexity due to its
successive detection of symbols. In this paper, we propose a modified V-BLAST
algorithm to decrease the computational complexity by reducing the number of
detection iterations required in MIMO communication systems. We begin by
showing the existence of a maximum number of iterations, beyond which, no
significant improvement is obtained. We establish a criterion for the number of
maximum effective iterations. We propose a modified algorithm that uses the
measured SNR to dynamically set the number of iterations to achieve an
acceptable bit-error rate. Then, we replace the feedback algorithm with an
approximate linear function to reduce the complexity. Simulations show that
significant reduction in computational complexity is achieved compared to the
ordinary V-BLAST, while maintaining a good BER performance.Comment: 6 pages, 7 figures, 2 tables. The final publication is available at
www.aece.r
Performance of reinforced collapsible soils
Geotechnical engineers face serious problems when construction sites contain collapsible soils, which are known by their strength when dry and experience sudden and excessive settlement when inundated. The amount of soil collapse depends on the extent of the wetting zone and the degree of saturation reached when the surface water is the source of inundation. On the other hand, full saturation of the collapsible soil and accordingly, the maximum collapse are expected when the source of inundation is the rise of groundwater table. In this thesis, experimental investigation was carried out on prototype set-up to simulate the case of a surface rigid strip footing resting on collapsible soils. The objective of this research has been to evaluate the collapse settlement of the footing when the collapsible soils are subjected to full inundation due to the rise of ground water table. The case of footings on homogeneous collapsible soils having various collapse potentials, heights and applied stresses were first examined. Then, the case of footing resting on partially replaced collapsible soils by compacted sand was tested to establish the optimum thickness of the soil replaced on the collapse settlement of these footings. In addition, tests were carried out on these footings where geosynthetic layers were placed at the interface between the replaced and the collapsible soil layers and within the replaced soil layer. Analytical and empirical models were developed to predict the collapse settlement of these footings for a given soil / replacement layer / geotextile layer conditions. Design procedures and charts were provided for practicing use
Incidence, Bacterial causes and Antibiotic Resistance Patterns of Urinary Tract Infection in Pet Animals
T The primary goal of the study was to determine the prevalence and various bacterial risks of lower urinary tract infections (UTI) in diseased and seemingly healthy pet animals with and without urine retention whether they were catheterized or not. The bacterial isolates were in vitro tested for their antibiotic resistance and antibiotic resistance genes were investigated. Between October 2020 and January 2022, 128 urine samples were randomly collected from pets recruited to veterinary hospitals and clinics in Cairo and Giza. Samples were cultivated for bacteriological isolation. Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Klebsiella spp. were found to be the most common bacterial causes of urinary tract infections in pets, with prevalence rates of 32.9%, 28%, and 19.5%, respectively followed by Proteus mirabilis (P. mirabilis) and Pseudomonas aeruginosa (P. aeruginosa) with incidences of 18.2% and 1.2%, respectively. Based on bacterial types and their virulence genes, antibiotic resistance and multi-drug resistance (MDR) behaviour varied. Epidemiology, diagnosis, and control of the urinary tract infection would benefit from the identification and characterization of isolated bacterial species
Bilateral Brachial Plexus Home Going Catheters After Digital Amputation for Patient With Upper Extremity Digital Gangrene
Peripheral nerve catheter placement is used to control surgical pain. Performing bilateral brachial plexus block with catheters is not frequently performed; and in our case sending patient home with bilateral brachial plexus catheters has not been reported up to our knowledge. Our patient is a 57 years old male patient presented with bilateral upper extremity digital gangrene on digits 2 through 4 on both sides with no thumb involvement. The plan was to do the surgery under sequential axillary blocks. On the day of surgery a right axillary brachial plexus block was performed under ultrasound guidance using 20 ml of 0.75% ropivacaine. Patient was taken to the OR and the right fingers amputation was carried out under mild sedation without problems. Left axillary brachial plexus block was then done as the surgeon was closing the right side, two hours after the first block was performed. The left axillary block was done also under ultrasound using 20 ml of 2% mepivacaine. The brachial plexus blocks were performed in a sequential manner. Surgery was unremarkable, and patient was transferred to post anesthetic care unit in stable condition. Over that first postoperative night, the patient complained of severe pain at the surgical sites with minimal pain relief with parentral opioids. We placed bilateral brachial plexus catheters (right axillary and left infra-clavicular brachial plexus catheters). Ropivacaine 0.2% infusion was started at 7 ml per hour basal rate only with no boluses on each side. The patient was discharged home with the catheters in place after receiving the appropriate education. On discharge both catheters were connected to a single ON-Q (I-flow Corporation, Lake Forest, CA) ball pump with a 750 ml reservoir using a Y connection and were set to deliver a fixed rate of 7 ml for each catheter. The brachial plexus catheters were removed by the patient on day 5 after surgery without any difficulty. Patient's postoperative course was otherwise unremarkable. We concluded that home going catheters are very effective in pain control postoperatively and they shorten the period of hospital stay
Influence of microclimatic ammonia levels on productive performance of different broilers' breeds estimated with univariate and multivariate approaches
Background and Aim: Birds litter contains unutilized nitrogen in the form of uric acid that is converted into ammonia; a fact that does not only affect poultry performance but also has a negative effect on people's health around the farm and contributes in the environmental degradation. The influence of microclimatic ammonia emissions on Ross and Hubbard broilers reared in different housing systems at two consecutive seasons (fall and winter) was evaluated using a discriminant function analysis to differentiate between Ross and Hubbard breeds.
Materials and Methods: A total number of 400 air samples were collected and analyzed for ammonia levels during the experimental period. Data were analyzed using univariate and multivariate statistical methods.
Results: Ammonia levels were significantly higher (p0.05) were found between the two farms in body weight, body weight gain, feed intake, feed conversion ratio, and performance index (PI) of broilers. Body weight; weight gain and PI had increased values (p0.05). Test of significance of discriminant function analysis did not show a classification based on the studied traits suggesting that they cannot been used as predictor variables. The percentage of correct classification was 52% and it was improved after deletion of highly correlated traits to 57%.
Conclusion: The study revealed that broiler's growth was negatively affected by increased microclimatic ammonia concentrations and recommended the analysis of broilers' growth performance parameters data using multivariate discriminant function analysis
Fabrication and In Vitro Characterization of a Tissue Engineered PCL-PLLA Heart Valve.
Heart valve diseases are among the leading causes of cardiac failure around the globe. Nearly 90,000 heart valve replacements occur in the USA annually. Currently, available options for heart valve replacement include bioprosthetic and mechanical valves, both of which have severe limitations. Bioprosthetic valves can last for only 10-20 years while patients with mechanical valves always require blood-thinning medications throughout the remainder of the patient's life. Tissue engineering has emerged as a promising solution for the development of a viable, biocompatible and durable heart valve; however, a human implantable tissue engineered heart valve is yet to be achieved. In this study, a tri-leaflet heart valve structure is developed using electrospun polycaprolactone (PCL) and poly L-lactic acid (PLLA) scaffolds, and a set of in vitro testing protocol has been developed for routine manufacturing of tissue engineered heart valves. Stress-strain curves were obtained for mechanical characterization of different valves. The performances of the developed valves were hemodynamically tested using a pulse duplicator, and an echocardiography machine. Results confirmed the superiority of the PCL-PLLA heart valve compared to pure PCL or pure PLLA. The developed in vitro test protocol involving pulse duplicator and echocardiography tests have enormous potential for routine application in tissue engineering of heart valves
Synthesis, characterization and molecular modeling of new ruthenium(II) complexes with nitrogen and nitrogen/oxygen donor ligands
Ru(II) complexes with some dinitrogen ligands; 3,4-diamino benzoic acid (DABA), 2-hydazinopyridine (hzpy), 2,2′-bipyridyl (bipy) and anthranilic acid (anth) have been synthesized and characterized by using IR, mass, and UV–Vis spectrometry and thermal analysis. The thermodynamic parameters (ΔE, ΔH, ΔS and ΔG) have been calculated by using Coats–Redfern and Horowitz–Metzger methods. The electrochemical properties of these complexes have been studied by using cyclic voltammetry. The evaluated energies of the HOMO and LUMO are in the range of −4.94 to −4.85 eV and −2.86 to −2.68 eV, respectively. The complexes have been proven to have an octahedral geometry with DABA, hzpy and bipy as N2 donor ligands and NSC as monodentate ligand. The structure of the Ru(II) complexes has been geometrically optimized by using parameterized PM3 semiempirical method. © 2015 The Author
Two decades of experience in explantation and graft preserving strategies following primary endovascular aneurysm repair and lessons learned
ObjectivesWe aim to scrutinize our evolving re-intervention strategies following primary endovascular aortic aneurysm repair (EVAR) - EVAR GORE SalvAge Fabric Technique (ARAFAT), aortic sac double breasting with endograft preservation, and stent-graft explantation.MethodsWe performed 1,555 aortic interventions over the study period, including 910 EVARs. Factors associated with the need for reintervention and the likelihood of chronic fabric fatigue failure (CFFF) were investigated. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 136 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV).ResultsForty-four (4.84%) patients underwent re-intervention post-primary EVAR; 18 ARAFATs, 12 double breastings, and 14 explantations. Choice of re-intervention was based on patient fitness and mode of failure. Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while mean time to re-intervention was 70.20 ± 6.98 months. The mean sac size before the primary EVAR and re-intervention was 6.00 ± 1.75 cm and 7.51 ± 1.94 cm, respectively. Polyester (61.40%) was the most commonly employed stent-graft material. Use of more than three modular stent-graft components (3.42 ± 1.31, p = 0.846); with the proximal stent-graft diameter of 31.6 ± 3.80 cm (p = 0.651) and the use of iliac limbs more than 17 mm (p = 0.364), all added together are contributing factors. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure.ConclusionsOur re-intervention strategies matured from stent graft explantation to graft preservation with endovascular relining of the stent-graft. Graft preservation with aortic sacotomy and double breasting were used to manage concealed ELs due to aortic hygroma
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