Little evidence for fast mapping in adults with developmental amnesia.

Cooper, Greve, and Henson (this issue) conclude that hippocampal-independent learning, as operationalised by 'fast mapping' (FM), is unlikely to facilitate learning in adults. We provide evidence from patients with Developmental Amnesia (DA), who acquire language and semantic knowledge despite early hippocampal pathology. We administered an FM paradigm to three patients with DA and controls. Patients showed no benefit of FM compared to explicit encoding. These data support the conclusion that FM is unlikely to facilitate learning in amnesia, regardless of age at onset. Hippocampal-independent learning may be possible in adults with DA, but such learning requires a prolonged consolidation period

Epidemiology of Poisoning in Northeast of Iran (2004-2013)

Background: Poisoning is a major concern, especially in developing countries. We aimed to focus on poisoning trends based on registry data for the recent 10 years.Methods: This cross-sectional study was performed on registry database of Imam Reza Hospital in Mashhad, Iran. All cases of toxic exposure or poisoning during 2004 to 2013 were included (49189 patients). Data from two national censuses were used for calculating rates. SPSS 11.5 was used for data analysis. P<0.05 was considered statistically significant.Results: There were 49189 admissions during the 10-year period with a mean age of 26.21±14.97 years out of which 50.3% were female. The prevalence rate had increased three times in women and four times in men. Pharmaceutical toxins (63.5%) had the highest proportional mortality ratio, which mostly occurred in winters. The mean age of admission began to decline again in recent years.Conclusion: Analyzing data on secular trends can always enlighten the healthcare decision makers for real health problems. Designing the proper population-based interventions can be one of the many uses of these findings

Using recognition testing to support semantic learning in developmental amnesia

Patients with developmental amnesia (DA) have suffered hippocampal damage in infancy and subsequently shown poor episodic memory, but good semantic memory. It is not clear how patients with DA learn semantic information in the presence of episodic amnesia. However, patients with DA show good recognition memory and it is possible that semantic learning may be supported by recognition. Building on previous work, we compared two methods for supporting semantic learning in DA; recognition-learning and recall-learning. In each condition, a patient with DA (aged 8 years) was presented with semantic information in animated videos. After each presentation of a video, learning was supported by an immediate memory test. Two videos were paired with a cued recall test. Another two videos were paired with a multiple-choice test to enable recognition-based learning. The outcome measure was semantic recall performance after a short delay of 30 min and a long delay of one week. Results showed a benefit of recognition-learning compared to recall-learning on cued recall in the patient with DA (76% vs. 35%). This finding indicates that young people with severe hippocampal damage can utilize recognition to support semantic learning. This has implications for the support of school-aged children with episodic memory difficulties

Search efficiency of discrete fractional Brownian motion in a random distribution of targets

Efficiency of search for randomly distributed targets is a prominent problem in many branches of the sciences. For the stochastic process of Lévy walks, a specific range of optimal efficiencies was suggested under variation of search intrinsic and extrinsic environmental parameters. In this paper, we study fractional Brownian motion as a search process, which under parameter variation generates all three basic types of diffusion, from sub- to normal to superdiffusion. In contrast to Lévy walks, fractional Brownian motion defines a Gaussian stochastic process with power-law memory yielding antipersistent, respectively persistent motion. Computer simulations of search by time-discrete fractional Brownian motion in a uniformly random distribution of targets show that maximising search efficiencies sensitively depends on the definition of efficiency, the variation of both intrinsic and extrinsic parameters, the perception of targets, the type of targets, whether to detect only one or many of them, and the choice of boundary conditions. In our simulations, we find that different search scenarios favor different modes of motion for optimising search success, defying a universality across all search situations. Some of our numerical results are explained by a simple analytical model. Having demonstrated that search by fractional Brownian motion is a truly complex process, we propose an overarching conceptual framework based on classifying different search scenarios. This approach incorporates search optimization by Lévy walks as a special case

Estimation levels of CTHRC1and some cytokines in Iraqi patients with Rheumatoid Arthritis

Collagen triple helix repeat containing-1 (CTHRC1) is an essential marker for Rheumatoid Arthritis (RA), but its relationship with pro-inflammatory, anti-inflammatory, and inflammatory markers has been scantily covered in extant literature. To evaluate the level of CTHRC1 protein in the sera of 100 RA patients and 25 control and compare levels of tumour necrosis factor alpha (TNF-α), interleukin 10 (IL-10), RA disease activity (DAS28), and inflammatory factors. Higher significant serum levels of CTHRC1 (29.367 ng/ml), TNF-α (63.488 pg/ml), and IL-10 (67.1 pg/ml) were found in patient sera as compared to that in control sera (CTHRC1 = 15.732 ng/ml, TNF-α = 33.788 pg/ml, and IL-10 = 25.122 pg/ml). There was no significant correlation between the level of serum CTHRC1 and DAS28 (r = 0.046, P = 0.650), while there were positive significant correlations between the levels of serum CTHRC1 and CRP (r = 0.372, P = 0.0001), ACPA (r = 0.254, P = 0.01), TNF-α (r = 0.202, P = 0.044), and IL-10 (r = 0.260, P = 0.0001). The level of CTHRC1 (> 25.385 ng/ml) in combination with the levels of CRP and ACPA provided a good indication of RA prediction with sensitivity = 71.0%, specificity = 100.0%, accuracy = 0.71%, positive predictive value (PPV) = 100.0%, and negative predictive value (NPV) = 46.3%. The study showed a significant correlation between the levels of CTHRC1 and TNF-α, and IL-10. These molecules may play a prominent role in the diagnostic and etiology of R

Hippocampal and diencephalic pathology in developmental amnesia.

Developmental amnesia (DA) is a selective episodic memory disorder associated with hypoxia-induced bilateral hippocampal atrophy of early onset. Despite the systemic impact of hypoxia-ischaemia, the resulting brain damage was previously reported to be largely limited to the hippocampus. However, the thalamus and the mammillary bodies are parts of the hippocampal-diencephalic network and are therefore also at risk of injury following hypoxic-ischaemic events. Here, we report a neuroimaging investigation of diencephalic damage in a group of 18 patients with DA (age range 11-35 years), and an equal number of controls. Importantly, we uncovered a marked degree of atrophy in the mammillary bodies in two thirds of our patients. In addition, as a group, patients had mildly reduced thalamic volumes. The size of the anterior-mid thalamic (AMT) segment was correlated with patients' visual memory performance. Thus, in addition to the hippocampus, the diencephalic structures also appear to play a role in the patients' memory deficit

Effects of Gas Cross-over through the Membrane on Water Management in the Cathode and Anode Sides of PEM Fuel Cell

Water management in a proton exchange membrane fuel cell (PEMFC) is numerically modeled by considering the 2D, non-isothermal steady flow assumptions. Governing equations are solved in all cell layers including cathode and anode electrodes by finite volume method using a single-region approach. The effect of gas cross-over through the membrane is studied on cell performance. This consideration, not only improves the general accuracy of modeling but also makes it possible to model energy losses due to direct reaction of reactant gases. The effect of some key variables such as liquid water diffusivity, current density, membrane thickness, etc. on PEMFC conditions such as the amount of saturated liquid water, power density, cell temperature, cross-over efficiency and so on are examined. It was observed that the amount of saturated liquid water on the anode side is considerably important. This observation addresses needs for further investigation of liquid water behavior in the anode electrode. The amount of liquid water saturation in both the cathode and anode electrodes is increased with increasing the current density. The results showed that at the current density of 0.2 A/cm2, cross-over effect causes about 10% reduction in cell efficiency and by decreasing the current density this effect is enhanced