Missing the trees for the forest: A construal level account of the illusion of explanatory depth.

An illusion of explanatory depth (IOED) occurs when people believe they understand a concept more deeply than they actually do. To date, IOEDs have been identified only in mechanical and natural domains, occluding why they occur and suggesting that their implications are quite limited. Six studies illustrated that IOEDs occur because people adopt an inappropriately abstract construal style when they assess how well they understand concrete concepts. As this mechanism predicts, participants who naturally adopted concrete construal styles (Study 1) or were induced to adopt a concrete construal style (Studies 2–4 and 6), experienced diminished IOEDs. Two additional studies documented a novel IOED in the social psychological domain of electoral voting (Studies 5 and 6), demonstrating the generality of the construal mechanism, the authors also extended the presumed boundary conditions of the effect beyond mechanical and natural domains. These findings suggest a novel factor that might contribute to such diverse social-cognitive shortcomings as stereotyping, egocentrism, and the planning fallacy, where people adopt abstract representations of concepts that should be represented concretely. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biomechanical and densitometric bone properties after callus distraction in sheep

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.     

Acute non-A-E hepatitis in the United States and the role of hepatitis G virus infection. Sentinel Counties Viral Hepatitis Study Team

BACKGROUND: Little is known about the relation of the newly discovered hepatitis G virus (HGV) to the cause and clinical course of acute and chronic viral hepatitis. METHODS: We selected patients from a surveillance study of acute viral hepatitis in four U.S. counties who had acute disease during 1985 to 1986 or 1991 to 1995. Serum samples were tested for HGV RNA by the polymerase chain reaction. RESULTS: HGV RNA was detected in 4 of 45 patients with a diagnosis of non-A-E hepatitis (9 percent), 23 of 116 patients with hepatitis C (20 percent), 25 of 100 patients with hepatitis A (25 percent), and 32 of 100 patients with hepatitis B (32 percent) (P<0.05 for the comparison of hepatitis B with hepatitis non-A-E or C). The clinical characteristics of the acute illness were similar for patients with HGV alone and those with hepatitis A, B, or C with or without HGV infection. During a follow-up period of one to nine years, chronic hepatitis did not develop in any of the patients with HGV alone, but 75 percent were persistently positive for HGV RNA, as were 87 percent of those with both hepatitis C and HGV infection. The rates of chronic hepatitis were similar in patients with hepatitis C alone (60 percent) and those with both hepatitis C and HGV infection (61 percent). CONCLUSIONS: The evidence from this surveillance study does not implicate HGV as an etiologic agent of non-A-E hepatitis. Persistent infection with HGV was common, but it did not lead to chronic disease and did not affect the clinical course in patients with hepatitis A, B, or C.     

Differentiation of emotions in laughter at the behavioral level.

Although laughter is important in human social interaction, its role as a communicative signal is poorly understood. Because laughter is expressed in various emotional contexts, the question arises as to whether different emotions are communicated. In the present study, participants had to appraise 4 types of laughter sounds (joy, tickling, taunting, schadenfreude) either by classifying them according to the underlying emotion or by rating them according to different emotional dimensions. The authors found that emotions in laughter (a) can be classified into different emotional categories, and (b) can have distinctive profiles on W. Wundt’s (1905) emotional dimensions. This shows that laughter is a multifaceted social behavior that can adopt various emotional connotations. The findings support the postulated function of laughter in establishing group structure, whereby laughter is used either to include or to exclude individuals from group coherence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lipid Composition and State of Oxidation of Fortified Infant Flours in Low‐Income Countries Are Not Optimal and Strongly Affected by the Time of Storage

Food fortification is widely used to address the public health problem of nutrient deficiencies. This study's purpose is to assess the lipid profile and nutritional quality of 13 fortified infant flours (FI) collected “in the field” in Africa and Asia after different periods of storage. The lipid content, fatty acid profiles, lipophilic vitamin content, and lipid oxidation state (peroxide values, secondary oxidation products) are determined. Mycotoxins and packaging materials are also characterized. The lipid content averages 9.1 ± 3.5 g/100 g. Fatty acid profiles are dominated by linoleic (43.3 ± 8.8%), oleic (29.5 ± 7.4%), and palmitic acid (17.8 ± 6.7%) and result in an average ω6/ω3 ratio of 12.2 ± 5.9 but with high values for some FI. Very high overages in vitamins A, D, and E are observed in products stored for short periods (1–6 months), whereas FI stored for more than 12 months has insufficient vitamin content. Lipid oxidation is acceptable but for six products presenting excessive peroxide values. Most products are contaminated by low amounts of mycotoxins but only two FI do not abide by the regulation. A strong correlation between peroxide values, hexanal content, and time of storage is observed. Practical Applications: The expiration dates for FI commercialized in low‐income countries should be shortened from 36 to 12 months so as to guarantee their nutritional quality of these functional foods and to abide by the fortified infant flour legislation. Indeed, FI quality significantly decreases over time of storage. The use of high barrier packaging materials must be generalized, although it is a necessary criterion but not sufficient to ensure the long‐term stability of FI. Special attention should be given to reduce lipophilic vitamin overages and to improve their lipid profile, especially the ω6/ω3 ratio, which has to be lower than 15.     

Hepatitis C: Part II. Prevention counseling and medical evaluation

An estimated 3.9 million Americans are infected with hepatitis C virus (HCV), and most do not know that they are infected. This group includes persons who are at risk for HCV-associated chronic liver disease and who also serve as reservoirs for transmission of HCV to others. Because there is no vaccine to prevent HCV infection and immune globulin is not effective for postexposure prophylaxis, prevention of HCV infection is paramount. Patients who are at risk of exposure to HCV should be advised on steps they might take to minimize their risk of infection. Patients who are infected with HCV should be counseled on ways to prevent transmission of HCV to others and to avoid hepatotoxins. They should also be examined for liver disease and referred for treatment, if indicated.     

p53-dependent ceramide response to genotoxic stress

Both p53 and ceramide have been implicated in the regulation of growth suppression. p53 has been proposed as the "guardian of the genome" and ceramide has been suggested as a "tumor suppressor lipid. " Both molecules appear to regulate cell cycle arrest, senescence, and apoptosis. In this study, we investigated the relationship between p53 and ceramide. We found that treatment of Molt-4 cells with low concentrations of actinomycin D or gamma-irradiation, which activate p53-dependent apoptosis, induces apoptosis only in cells expressing normal levels of p53. In these cells, p53 activation was followed by a dose- and time-dependent increase in endogenous ceramide levels which was not seen in cells lacking functional p53 and treated similarly. Similar results were seen in irradiated L929 cells whereby the p53-deficient clone was significantly more resistant to irradiation and exhibited no ceramide response. However, in p53-independent systems, such as growth suppression induced by TNF-alpha or serum deprivation, ceramide accumulated irrespective of the upregulation of p53, indicating that p53 regulates ceramide accumulation in only a subset of growth-suppressive pathways. Finally, ceramide did not increase p53 levels when used at growth-suppressive concentrations. Also, when cells lacking functional p53, either due to mutation or the expression of the E6 protein of human papilloma virus, were treated with exogenous ceramide, there was equal growth suppression, cell cycle arrest, and apoptosis as compared with cells expressing normal p53. These results indicate that p53 is unlikely to function "downstream" of ceramide. Instead, they suggest that, in situations where p53 performs a critical regulatory role, such as the response to genotoxic stress, it functions "upstream" of ceramide. These studies begin to define a relationship between these two pathways of growth inhibition.     

3-D pose from 3 points using weak-perspective

This correspondence discusses computing the pose of a model from three matching point pairs under weak-perspective projection. A new approach to the problem that is motivated geometrically is described. Like previous methods, the method here involves solving a biquadratic equation, but here the biquadratic's solutions, comprised of an actual and a false solution, are interpreted graphically. The final equations take a new form, which leads to a simple expression for the image position of any unmatched model point     

Current perspective on fast reactor containment

The concept of “containment” is to provide a series of physical barriers between the radioactive products of the fission process and the public. All nuclear reactors have several such barriers and LMFBRs have more than most. These barriers are, successively:

1. fuel, which retains fission products;

2. fuel cladding, which encloses the fuel;

3. sodium coolant, which absorbs fission products released through fuel caldding;

4. primary coolant boundary, which has energy absorption and leakage control capabilities;

5. containment building, hereafter referred to as containment, which provides the final engineered barrier for control of radioactive releases;

6. exclusion distance, which provides space for natural attenuation of radioactive releases before reaching the public.

These barriers, along with the design approaches and features which protect their integrity under normal and accident conditions, assure that the public is adequately protected from the potential hazards of radioactivity residing in the core. It is only in the case of hypothesized core disruptive accidents (HCDAs) that these successive barriers can be sufficiently threatened as to pose a significant threat to the public. These HCDAs involve an extremely low probability sequence of successive failures resulting in core cooling imbalances which lead to fuel overheating. Under such conditions, the fuel and cladding barriers can be lost and energy sources can be generated which threaten the primary coolant boundary and containment. This paper addresses current perspectives on containment of HCDAs with emphasis on the approach and programs in the US.