On Optimal Pointwise in Time Error Bounds and Difference Quotients for the Proper Orthogonal Decomposition

In this paper, we resolve several long standing issues dealing with optimal pointwise in time error bounds for proper orthogonal decomposition (POD) reduced order modeling of the heat equation. In particular, we study the role played by difference quotients (DQs) in obtaining reduced order model (ROM) error bounds that are optimal with respect to both the time discretization error and the ROM discretization error. When the DQs are not used, we prove that both the ROM projection error and the ROM error are suboptimal. When the DQs are used, we prove that both the ROM projection error and the ROM error are optimal. The numerical results for the heat equation support the theoretical results

The implementation of a novelty concept and measurement model for a developing B2B marketplace

Regardless of the market on which the company operates - B2B or B2C, brand and customer experience are the keys to success in the modern world. The B2C companies succeeded in adapting to the new trends, while B2B companies didn’t keep pace and missed the opportunity to experience the competitive advantage. The purpose of this work is to assess the brand equity through its elements – brand associations, brand attitudes, brand loyalty and other services and to identify the metrics such as Customer Lifetime Value and Retention that enforce the overall customer equity (Fig. 3.2.1). The literature was analysed and the approaches regarding brand equity and customer equity and the linkage between them were reviewed. Subsequently, the model proposed by Leone et al (2006) guided research in order to answer to the following questions: “Does a brand differentiate a distributor?” and “Are the brand equity and customer equity related in the Romanian developing B2B market?”, The quantitative research applied in this paper on a sample of 110 people from the cash- generators category showed that the brand equity is influenced by loyalty in a proportion of 29.9%. However, the conclusion is that it cannot be assumed a linear relation between brand and customer equity in the current research, from the perspective of a tyre and construction materials distributor, that operates in a developing economy. The recommendations highlights loyalty as an essential asset for Dynamic 92 who experiences long-term relationships and promising recommendations (see Net promoter score is over 70%) However, the customers are not alike and therefore the implementation of Customer Lifetime Value as a managerial KPI used in modern economies, assists the sales managers to evaluate the purchasing behaviour of up mentioned customers, to monitor their retention and the customer’s cost centre. This project could generate the company’s empowerment by the novelty and differentiation in the Romanian environment and it ensures the conditions for the company to compete with international distributors, on equal terms/positions

Our policy in intraventricular colloid cysts. Experience of 31 operated cases.

The colloid cyst of the third ventricle is abenign tumor situated in the anterior partof the third ventricle. This lesion representsless than 1% of the primary brain tumorbeing more common in young adults.Because of its particular location, thecolloid cyst can obstruct the Monroforamen, producing intermittentintracranian hypertension with headache,vomiting and visual disturbances. Thirtyonecases of colloid cysts have beenoperated using the microsurgical approachin the First Neurosurgical Department ofEmergency Clinical Hospital “Bagdasar-Arseni” between January 1995 andDecember 2008. The age of the patientswas between 17 and 46 years, with amedium age of 31 years. The follow-upperiod was between 9 months and 7 years.In three cases TTA approach has beenperformed. One of the cases developed avenous cerebral infarct after this procedure,but the patient had finally a good outcome.For 28 patients the transcortical approachhas been performed. In all cases the totalresection of the colloid cyst has beenperformed. Of all 31 cases, one casepresented a transitory hemiparesis, twocases showed negativist behavior, and threecases had transitory memory disturbances.There was no intraventricular hemorrhageafter colloid cyst resection in our series. Inconclusion, according to our policy, themicrosurgical approach is the besttreatment for third ventricular colloid cystsbecause of its main advantages comparedwith the endoscopic approach: thepossibility of total resection of the cyst, thegood control of the bleeding source duringthe procedure, and a better exposure of theanatomical landmarks

The nature of phenotypic variation in Pavlovian conditioning

Pavlovian conditioning procedures result in dramatic individual differences in the topography of learnt behaviors in rats: When the temporary insertion of a lever into an operant chamber is paired with food pellets, some rats (known as sign-trackers) predominantly interact with the lever, while others (known as goal-trackers) predominantly approach the food well. Two experiments examined the sensitivity of these two behaviors to changing reinforcement contingencies in groups of males and female rats exhibiting the different phenotypes (i.e., sign-trackers and goal-trackers). In both phenotypes, behavior oriented to the food well was more sensitive to contingency changes (e.g., a reversal in which of two levers was reinforced) than was lever-oriented behavior. That is, the nature of the two behaviors differed independently of the rats in which they were manifest. These results indicate that the behavioral phenotypes reflect the parallel operation of a stimulus-stimulus associative process that gives rise to food-well activity and a stimulus-response process that gives rise to leveroriented activity, rather than the operation of a single process (e.g., stimulus-stimulus) that generates both behaviors

Why we need systematic reviews and meta-analyses in the testing and assessment literature

Multivariate analysis of psychological dat

Incidental durotomy in lumbar spine surgery: Incidence, risk factors and management

Incidental durotomy is a common complication of lumbar spine operations for degenerative disorders. Its incidence varies depending on several risk factors and regarding the intra and postoperative management, there is no consensus. Our objective was to report our experience with incidental durotomy in patients who were operated on for lumbar disc herniation, lumbar spinal stenosis and revision surgeries. Between 2009 and 2012, 1259 patients were operated on for degenerative lumbar disorders. For primary operations, the surgical approach was mino-open, interlamar, uni- or bilateral, as for recurrences, the removal of the compressive element was intended: the epidural scar and the disc fragment. 863 patients (67,7%) were operated on for lumbar disc herniation, 344 patients (27,3%) were operated on for lumbar spinal stenosis and 52 patients (5%) were operated for recurrences. The operations were performed by neurosurgeons with the same professional degree but with different operative volume. Unintentional durotomy occurred in 20 (2,3%) of the patients with herniated disc, in 14 (4,07%) of the patients with lumbar spinal stenosis and in 12 (23%) of the patients who were operated on for recurrences. The most frequent risk factors were: obesity, revised surgery and the physician’s low operative volume. Intraoperative dural fissures were repaired through suture (8 cases), by applying muscle, fat graft or by applying curaspon, tachosil. There existed 4 CSF fistulas which were repaired at reoperation. Incidental dural fissures during operations for degenerative lumbar disorders must be recognized and immediately repaired to prevent complications such as CSF fistula, osteodiscitis and increased medical costs. Preventing, identifying and treating unintentional durotomies can be best achieved by respecting a neat surgical technique and a standardized treatment protocol

First measurements at the DAΦNE φ-factory with the DEAR experimental setup

The relevant background for the DEAR experiment } low-energy X rays and ionizing particles } present in the DEAR interaction region of the DA'NE e'e~ collider was investigated using the "rst-stage DEAR setup and CCD detectors. An extensive Monte Carlo simulation was performed for the present setup and beam conditions. Good quantitative agreement between measurements and simulation was achieved. This is a con"rmation that, with respect to the expected background, which gives an important contribution to the statistical precision of the experiment, the con"guration chosen to measure the strong interaction shift and width in kaonic hydrogen and kaonic deuterium can indeed reach the planned level of accuracy. ( 2000 Elsevier Science B.V. All rights reserved