Attention, automaticity, and developmental dyscalculia.

People suffering from developmental dyscalculia (DD) show an abnormal pattern of the size congruity effect. They do not display a facilitation component in a numerical Stroop task. In this task, participants are presented with 2 digits that differ both in physical size and numerical value, and they have to compare the digits while ignoring one of the dimensions. The present study examined performance of those with DD and control participants in the numerical Stroop task under cognitive load. The no-load condition replicated previous findings (i.e., lack of facilitation in the physical task for the DD group). Load had opposite effects on interference and facilitation. Load eliminated facilitation and increased interference in the control group. Load increased interference only in the physical task in the DD group. The opposite effect of load on facilitation and interference suggests that these components are related to different cognitive mechanisms. The fact that load produced a DD-like pattern in the control group could suggest that individuals with DD suffer from difficulty in recruiting attention in addition to the deficits in numerical processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interface fracture properties of a bimaterial ceramic composite

In this investigation, the interface fracture toughness is measured for a pair of ceramic clays which are joined together. The Brazilian disk specimen, which provides a wide range of mode mixity, is employed to measure these properties. Calibration equations relating the stress intensity factors to the applied load and geometry are determined by means of the finite element method and the M-integral. The effect of residual stresses is accounted for by employing a weight function to obtain the contribution to the stress intensity factors. Total stress intensity factors are obtained by superposition. These are employed to determine the critical interface energy release rate as a function of mode mixity from critical data obtained from tests carried out on the Brazilian disk specimens. An energy release rate fracture criterion is compared to the experimental results for .     

Major adverse reactions to yeast-derived hepatitis B vaccines--a review

Blood was taken from 49 Thoroughbred horses before and after racing at the track to determine if frusemide modified the apparent viscosity of the blood and to determine the effects of changes in shear rate and packed cell volume (PCV), associated with strenuous exercise, on apparent and relative viscosities. Small increases in apparent viscosity of the blood (at a specified PCV and shear rate) occurred in horses given frusemide compared to those receiving no frusemide; however, no differences were seen in relative viscosity. Although 2 groups of horses, those receiving frusemide before racing and those not receiving this drug were studied, the results suggest no influence of frusemide on any red blood cell variable that might modify apparent blood viscosity. Apparent viscosity of the blood was slightly (but significantly) higher after racing than before racing at any given PCV and shear rate, but relative viscosity was lower in the post race than in the prerace blood sample. The most important contributing factor to the increase in apparent viscosity in blood during racing is the increase in PCV, because the blood becomes nearly shear rate independent at shear rates likely to exist in the cardiovascular system during exercise. With an increase in PCV from 40 to 65% at shear rates above 225/s, apparent viscosity approximately doubled. However, this increase alone cannot account for the elevated pulmonary vascular pressure in the running horse, and additional factors, especially those causing the high left atrial pressure, must be considered. The cause of the elevated pressure may be multifactorial in nature.     

Algorithm optimization using a rule-based system. A case study: The Direct Kinematic Solution in robotics

The computation burden of intensive numerical real-time algorithms is a problem encountered in robotics and many other fields. A cost-effective solution for the implementation of these algorithms requires knowledge of computer architecture, compiler technology and algorithms. A cost-effective numeric processing methodology using a combined hardware-software approach and taking advantage of logic programming tools is presented. The methodology is based on optimizing the numerical calculation process of the algorithm. It also enables the specification of hardware resources. The process uses a rule-based-system (RBS) implemented in the logic programming language Prolog to automatically reduce the number of operations in the numerical execution of the algorithm and optimizes the use of hardware resources. The methodology provides a solution for the problems of handshake overhead and algorithm translation efficiency.The Direct Kinematics Solution (DKS), a robot arm control algorithm, is presented as a case study to illustrate the methodology. The proposed methodology has a general potential which can be extended to the optimization or implementation of different algorithms.     

Penicillin-resistant pneumococcal meningitis in Israel

Penicillin-resistant Streptococcus pneumoniae (PRP) is of worldwide concern. Treatment failures and fatalities of meningitis caused by PRP have been reported in other locations but not yet in Israel. We describe an 11-month-old infant with meningitis caused by PRP who failed to respond to initial treatment with cefotaxime. Vancomycin treatment caused a prompt cure. The minimal inhibitory concentrations of the isolate to penicillin, cefuroxime and cefotaxime were 1.0, 4.0 and 1.0 micrograms/ml, respectively. New guidelines for the treatment of meningitis in Israel are suggested.     

Why should a deformed, anaesthetic, functionless hand be wanted?

A 58-year-old woman presented at a disability assessment tribunal with a severely deformed left forearm. She had broken the arm 25 years previously and the infected open fracture had not healed. There were no sensory or motor functions in the hand, which the patient kept constantly hidden in her garments. The question of an amputation was raised and the advantages of modern prosthetics with respect to cosmesis and function failed to convince the patient that she might benefit from such surgery. One questions why a patient should want to retain this cumbersome, obviously embarrassing, burden and whether the question of surgery should have been raised.     

Differences between left- and right-hand reaction time rhythms: indications of shifts in strategies of human brain activity

Surgery for symptomatic hyperparathyroidism remains the standard therapy. Asymptomatic primary hyperparathyroidism (pHPT) is being diagnosed with increasing frequency owing to broad serum testing. Indications for surgery in this setting are controversial. For evaluation of surgical safety we performed a retrospective analysis of our patients who were being operated on for asymptomatic pHPT. From January 1988 until August 1995, 243 patients were treated for pHPT and registered prospectively at our unit. Seventy-six patients were classified as asymptomatic. In all, 75% of the patients were female; the mean age was 62 years. In this group, 87% of the patients had cervical sonography in order to localize the adenoma. Highly selective venous catheterization was required in cervical reexplorations. Statistical analysis for potential prognostic factors for the clinical outcome was performed. Successful cervical exploration was possible in 71 patients (94.7%). With 4 patients remaining hypercalcemic, the rate of persistency was 5.2%. Localization procedures were correct in 58% for cervical ultrasound and 77% for selective venous catheterization. Postoperative morbidity included one permanent recurrent laryngeal nerve palsy and 2 patients with hemorrhage who were treated by reoperation. While one case of permanent hypoparathyroidism was well controlled by oral supplementation, 18 patients recovered from temporary hypoparathyroidism. No postoperative mortality occurred. Risk factor analysis revealed only cervical reexplorations for HPT to be associated with a higher morbidity (P = 0.02). Surgery for asymptomatic pHPT can be performed with reasonable safety. Cervical reexplorations in asymptomatic patients should be reserved for special indications. Apart from this small group, all patients should be evaluated for surgery.     

Propellanes 100. The Nature of the Stereoelectronic Effect in the Highly Stereospecific Hydroxyl Elimination from syn,anti-[4.3.3]Propellane-8,11-diol upon Isobutane Chemical Ionization

A stereospecific ¹⁸O-labelling study shows that the syn-hydroxy group is preferentially lost from the syn, anti-title diol upon i-C₄H₁₀ chemical ionization, indicating occurrence of a stereoelectronic effect in this process. A collision-induced dissociation study of deuterium- and ¹⁸O-labelled analogs shows that a symmetrical ether structure is not formed in the above process by an S_Ni mechanism. This result leads to the conclusion that the stereoelectronic assistance of the anti-OH group in the loss of the syn-hydroxyl is expressed either in a weak transition state interaction or by other processes such as β-elimination via hydrogen transfer with concomitant double bond formation.     

Automated agents for reward determination for human work in crowdsourcing applications

Crowdsourcing applications frequently employ many individual workers, each performing a small amount of work. In such settings, individually determining the reward for each assignment and worker may seem economically beneficial, but is inapplicable if manually performed. We thus consider the problem of designing automated agents for automatic reward determination and negotiation in such settings. We formally describe this problem and show that it is NP-hard. We therefore present two automated agents for the problem, based on two different models of human behavior. The first, the Reservation Price Based Agent (RPBA), is based on the concept of a RP, and the second, the No Bargaining Agent (NBA) which tries to avoid any negotiation. The performance of the agents is tested in extensive experiments with real human subjects, where both NBA and RPBA outperform strategies developed by human experts.