CLASS SIZE EFFECTS ON STUDENT ACHIEVEMENT: HETEROGENEITY ACROSS ABILITIES AND FIELDS

In this paper we analyze class size effects on college students exploiting data from a project offering special remedial courses in Mathematics and Language skills to freshmen enrolled at an Italian medium sized public University. To estimate the effects of class size we take advantage of the fact that students and teacher where virtually randomly assigned to teaching classes of different sizes. From our analysis it emerges that, controlling for a number of individual characteristics, larger classes determine a significant and sizeable negative effect on student performance in Mathematics. Importantly, this negative effect is significantly larger for low ability students and negligible for high ability students. On the other hand, class size effects do not appear to be relevant for student achievement in Language Skills.Class size, student achievement, educational production function

Human Factors Issues and the Risk of High Voltage Equipment: Are Standards Sufficient to Ensure Safety by Design?

High voltage equipment is mostly designed according to technically prescriptive standards requirements based on electrical engineering safety principles. However a more risk-based approach to standards and regulation may be advisable to enable designer and user to take an active role in establishing that their installation is inherently safe. The use of Gas Insulated Switchgear (GIS) for instance is enabling the new substation to be housed indoors and condensed into around one quarter of the space. The manufacturers argue that design improvements in GIS make it virtually “maintenance free”, comply with all the relevant standards. However some of these improvements have implications for the operators that need to be taken into account. Commissioning, operational checks and inspections and the occasional maintenance interventions are activities during which the technicians need to interface with the equipment, the issues regarding the interfaces provided have been analysed to identify their relevance in the overall risk assessment of the equipment. The paper reports about a study aimed at verifying through a risk analysis the impacts that the issues related to deficit in ergonomic design may present for the overall availability and safety of the plant. Those issues are not tackled in the technical standards and/or designers current practice

Parkinson's disease: autoimmunity and neuroinflammation

Parkinson's disease is a neurodegenerative disease that causes the death of dopaminergic neurons in the substantia nigra. The resulting dopamine deficiency in the basal ganglia leads to a movement disorder that is characterized by classical parkinsonian motor symptoms. Parkinson's disease is recognized as the most common neurodegenerative disorder after Alzheimer's disease. PD ethiopathogenesis remains to be elucidated and has been connected to genetic, environmental and immunologic conditions. The past decade has provided evidence for a significant role of the immune system in PD pathogenesis, either through inflammation or an autoimmune response. Several autoantibodies directed at antigens associated with PD pathogenesis have been identified in PD patients. This immune activation may be the cause of, rather than a response to, the observed neuronal loss. Parkinsonian motor symptoms include bradykinesia, muscular rigidity and resting tremor. The non-motor features include olfactory dysfunction, cognitive impairment, psychiatric symptoms and autonomic dysfunction. Microscopically, the specific degeneration of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies, which are brain deposits containing a substantial amount of α-synuclein, have been recognized. The progression of Parkinson's disease is characterized by a worsening of motor features; however, as the disease progresses, there is an emergence of complications related to long-term symptomatic treatment. The available therapies for Parkinson's disease only treat the symptoms of the disease. A major goal of Parkinson's disease research is the development of disease-modifying drugs that slow or stop the neurodegenerative process. Drugs that enhance the intracerebral dopamine concentrations or stimulate dopamine receptors remain the mainstay treatment for motor symptoms. Immunomodulatory therapeutic strategies aiming to attenuate PD neurodegeneration have become an attractive option and warrant further investigation

H2O2 Signature and Innate Antioxidative Profile Make the Difference Between Sensitivity and Tolerance to Salt in Rice Cells

Salt tolerance is a complex trait that varies between and within species. H2O2 profiles as well as antioxidative systems have been investigated in the cultured cells of rice obtained from Italian rice varieties with different salt tolerance. Salt stress highlighted differences in extracellular and intracellular H2O2 profiles in the two cell cultures. The tolerant variety had innate reactive oxygen species (ROS) scavenging systems that enabled ROS, in particular H2O2, to act as a signal molecule rather than a damaging one. Different intracellular H2O2 profiles were also observed: in tolerant cells, an early and narrow peak was detected at 5 min; while in sensitive cells, a large peak was associated with cell death. Likewise, the transcription factor salt-responsive ethylene responsive factor 1 (TF SERF1), which is known for being regulated by H2O2, showed a different expression profile in the two cell lines. Notably, similar H2O2 profiles and cell fates were also obtained when exogenous H2O2 was produced by glucose/glucose oxidase (GOX) treatment. Under salt stress, the tolerant variety also exhibited rapid upregulation of K+ transporter genes in order to deal with K+/Na+ impairment. This upregulation was not detected in the presence of oxidative stress alone. The importance of the innate antioxidative profile was confirmed by the protective effect of experimentally increased glutathione in salt-treated sensitive cells. Overall, these results underline the importance of specific H2O2 signatures and innate antioxidative systems in modulating ionic and redox homeostasis for salt stress tolerance

Total Safety Management: What Are the Main Concerns in the Integration of Best Available Methods and Tools

“BP released findings from its own internal investigation of the oil spill in the Gulf of Mexico, revealed inefficient Organization interfaces among BP management, the rig crew and well site leader. Also according to the investigation, one important contributor to the accident was inadequate guidelines for critical tests and operations”. (Pires and Mosleh 2011) Over the recent past, the accumulation of major mishaps, crises and accidents have made it clear that organisations must still improve their capabilities to address safety “not as a stand-alone activity that is separate from the main activities and processes of the organization” but as an integrated part of total performance management. The requirements for safety management in existing and upcoming standards and regulations, as for example the ISO 31000 and or the Seveso II directive, call for a proactive strategic approach, anticipating risks and demonstrating a capacity to keep safety at the centre of changes driven by commercial competition, and ensuring that safety evidence itself becomes an effective driver of change. However there is often a gap between the state principles and an actual roadmap to their implementation. Furthermore organisations, especially the one dealing with safety critical operations, find it difficult to integrate their different functional units in a common programme of operations management or change; there is no clear consensus about what it means to be ‘proactive’; there is no integrated framework for analysing or managing all the human related functions in an operational system. Innovation may rely on assembling the best practices, tools and methods already available for functional analysis, risk assessment, interactive emergency scenarios analysis, performance monitoring, design review, training and knowledge management, in an integrated framework able to address safety management in the main aspects of a product or process lifecycle the cornerstone of which is the building of a common operational picture to support the capacity to perform more participatory and dynamic risk identification and solutions loops in: - Design (new plants, processes /procedures availing new visualization tools) - Ad hoc critical activities (management of change or scheduled overhaul) - Operations management (establishing of dynamic risk registers). This is the scope of a new EU funded research project called TOSCA and the present paper will introduce the current framework being built

Phantoms in medicine: the case of ophthalmology

Physical and in-silico phantoms have revealed extremely useful in the development of new surgical techniques and medical devices and for training purposes. The fabrication of eye phantoms requires knowledge of anatomy and physical principles beyond the eye physiology and medical instruments used in the clinical scenario. After a proper definition of phantoms and the discussion about their classification, the present work reviews the various phantoms developed in ophthalmology, illustrating the rationale of their design

Alternating Hemiplegia of Childhood: Pharmacological treatment of 30 Italian patients

Background Alternating Hemiplegia of Childhood (AHC) is a severe disorder. Several drugs have been administered as prophylaxis for paroxysmal attacks, however, no therapy is completely effective. Methods Our aim is to review the pharmacological data related to the prophylactic and acute treatment of a cohort of 30 patients (16 M, 14 F, age range 5\u201342 years) and to correlate them with the clinical and genetic data collected through the Italian Biobank and Clinical Registry for AHC. Results Flunarizine was the most commonly used long-term treatment in the cohort; it reduced duration and frequency of attacks in 50% of patients and decreased intensity in 32.1%. In younger patients, flunarizine seemed significantly more effective in reducing intensity. We found no correlation between the effectiveness of flunarizine and genotype, or between developmental outcome and duration of treatment. In particular, 3 of our patients affected by E815K mutation presented rapid neurological deterioration despite ongoing treatment. Among the other administered prophylactic therapies, few proved to be effective (benzodiazepines, niaprazine, acetazolamide, melatonin, olanzapine, ketogenic diet). No clear rationale exists regarding their use, but these therapies may work by reducing the triggering factors. Conclusions The presented data are retrospective, but they are aimed at filling a gap given the rarity of the disease and the lack of randomized and controlled studies. Besides their usefulness in clarifying the pathophysiology of the disease, prospective studies involving larger cohorts of ATP1A3 mutated AHC patients are needed to provide a rationale for testing other molecules