Simulation is the process of executing a model that describes a system with enough detail; this model has its entities, an internal state, some input and output variables and a list of processes bound to these variables. Teaching a simulation language such as general purpose simulation system (GPSS) is always a challenge, because of the way it executes the models and the abstraction level it can achieve, very different compared with most well-known programming languages. This article presents an open source simulation framework that implements a subset of entities of GPSS, which could help students to improve the understanding of this language. This tool also stores all entities of simulations in every single simulation time, which is very useful for debugging simulations, but also for getting a detailed history of all entities in the simulations, knowing exactly how they have behaved in every simulation time. 相似文献
Many schools are faced with the prospect of soaring absenteeism rates, despite the use of traditional truancy courts and other legal interventions. A recent trend in the literature has been to explore alternative, hybrid, and multidisciplinary approaches to address the underlying obstacles to school attendance. These programs are often integrated into schools to reduce stigma and transportation burdens on families. The present study involved an evaluation of a truancy diversion program in nine at‐risk middle schools in an ethnically diverse sample. Graduates from the program demonstrated significant declines in internalizing and externalizing behavior problems. In addition, participants and their parents expressed high levels of perceived improvement in academic performance. Academic tutoring was found to differentiate program graduates from nongraduates. Results are preliminary but discussed within the context of the role of school attachment in truancy diversion programs. 相似文献
The medical ultrasonic phased array technology was modified for the non-destructive testing of marble sculptures and the feasibility of the approach was evaluated. For this purpose, 1?MHz, 64-channel phased array electronic and phased array transducers were developed. The specifications of the electronics and the transducers are presented and discussed. Ultrasound images of inner structures of a marble sculpture are presented. The problem of the acoustic matching layers for different states of deterioration is discussed and the developments in view of a suitable matching layer solution are presented. This matching layer is combined with a new coupling technique that protects the marble surface. The results of experiments on ultrasound phantoms and on a marble sculpture are presented. 相似文献
This paper aims at proposing a new calibration material for microdrilling resistance measurements. Microdrilling resistance is a microdestructive method mainly used in built heritage in order to determine the strength profile in depth. This method is suitable to detect changes in the material cohesion, either due to a different state of preservation or to the action of a consolidant. Calibration materials are often used in microdrilling measurements in order to characterise the drill bit initial value and to correct the variations existing within the initial values of a set of drill bits. Calibration materials are also useful to detect the wear effect on a drill bit due to an abrasive stone. Moreover, such materials can be used for comparing results obtained with different microdrilling machines. In this work, halite was chosen to be tested as a calibration material due to its properties, as low hardness and isotropy. Halite single crystals and halite salt stone from different provenances were tested in order to evaluate the suitability of this material to the requests of a calibration material for microdrilling resistance applications, as for instance being homogeneous, non-abrasive, sensitive and available worldwide. Experimental results show that halite from different provenances is very homogeneous, especially in the crystalline form. This form of halite is slightly more expensive than stone halite; however its costs are comparable to ARS and significantly lower than Macor (other calibration materials commonly used for microdrilling resistance measurements). Due to the advantages of halite for calibration purposes, this material should be further tested by other authors in order to validate our conclusions. 相似文献
Microvascular and macrovascular diseases are the main causes of morbidity in type 2 diabetes patients through chronic hyperglycaemic condition via oxidative stress and inflammation. Reactive oxygen species (ROS) activate p38 MAPK phosphorylation and inflammation which enhances protein modification by carbonylation. The use of metformin and a p38 MAPK inhibitor is hypothesised to reduce ROS production and inflammation but effects of metformin and p38 MAPK inhibitor (SB203580) on ROS production and inflammation in vascular type 2 diabetes mellitus non-obese (T2DM) have not been investigated. The Goto-Kakizaki rat T2DM model was divided into three groups as T2DM, T2DM treated with 15 mg/kg bw metformin and T2DM treated with 2 mg/kg bw SB203580 for 4 weeks. Rat aortas were isolated and protein carbonyl (PC) contents were measured by spectrophotometric DNPH assay. Aortic IL-1ß level was determined by ELISA. Results showed that aortic PC contents in the T2DM group were significantly higher than in non-diabetic rats. Treatment with metformin or SB203580 significantly reduced PC contents while only metformin significantly reduced IL-1ß levels. Findings indicated that metformin reduced ROS production and inflammation in diabetic vessels and possibly reduce vascular complications in non-obese T2DM. 相似文献
Children with deficits in executive functions (EFs) and impairments in pragmatic language have a range of cognitive and language difficulties that affect their literacy and educational achievements. As deficits in EFs and pragmatic impairments are characteristics of autism spectrum disorders, this study examined the associations between EFs and pragmatic skills in children with high-functioning autism (HFA). Fifteen children with HFA (5–9 years; M?=?7.44, SD 1.21), matched to 15 typically developing peers on age, gender, and non-verbal intelligence participated in the study. Children completed a pragmatic language assessment protocol, and a rating scale of EFs was administered to parents. Our results point to two main findings: children with HFA presented pragmatic difficulties and EFs impairments when compared with typically developing peers; and, as shown by a significant indirect effect of group on pragmatics via EFs, the poor pragmatics skills of HFA children were associated with their EFs difficulties. These findings may be of clinical relevance for children with pragmatic impairments, such as autism spectrum disorders. Future studies are crucial to further investigate the relationship between impaired pragmatics and EFs.
In recent experiments in which the social influences on feeding in Mongolian gerbils were investigated, observer gerbils acquired food preferences from conspecific demonstrators only if the demonstrators and observers were either related or familiar. Even then, the effects of demonstrator gerbils on observers’ food choices lasted less than 24 h. In similar experiments with Norway rats, the familiarity/relatedness of demonstrators and observers had little effect on social learning, and the demonstrators’ influence on observers’ food choices lasted many days. We examined the causes of these differences and found that, after observer gerbils interacted with either unfamiliar or familiar conspecific demonstrators that had been fed using procedures typically used to feed demonstrator rats, they showed long-lasting social learning about foods, whereas observer rats interacting with conspecific demonstrators that had been fed as demonstrator gerbils normally are fed showed effects of familiarity/relatedness to demonstrators on their social learning about foods. Procedural differences, rather than species differences, seem to be responsible for reported inconsistencies in social learning about foods by rats and gerbils. 相似文献