Attenuation of "acute" habituation by scopolamine in the black-tailed prairie dog (Cynomys ludovicianus).

Tested and confirmed the hypothesis that scopolamine attenuates habituation occurring within a training session as well as that occurring between training sessions. Subcutaneous scopolamine injections (.5 mg/kg) reduced spontaneous wheel running in 8 female prairie dogs. The same dosage did not affect the threshold for wheel running induced by electrical brain stimulation (EBS) in 6 Ss in Exp II. Exp III (n = 6) demonstrated that EBS-induced running declined during a 10-min stimulation period and indicated that the decline was habituative since the response was repeatedly dishabituated. In Exp IV .5 mg/kg of scopolamine reduced habituation of EBS-induced wheel running during 10-min sessions with the 6 Ss used in Exp II. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The selection of variable gear for minimum energy

The system under consideration is that of a motor, coupled by a gear train to an inertial load, where the requirement is to rotate the load by a given angle and come to a halt. The question considered is whether the use of a variable gear, instead of one with constant ratio, will reduce the required energy, and if so, what are the optimal gear ratio function and the corresponding control function.     

Commit protocols for externalized-commit heterogeneous database systems

In designing a heterogeneous database systems, one of the main technical challenges is developing techniques for ensuring global commit. That is, guaranteeing that a transaction spanning multiple individual database management systems (DBMSs) either commits at all the participating DBMSs or at none of them. Previous work in this area typically assumes that the participating DBMSs do not provide a mechanism for interacting with their commit facilities. While this is true in many cases, in practice there are systems which support a programmatic interface to their commit protocols. We refer to database systems offering such facilities asexternalized commit DBMSs.The focus of this paper is on commit protocols for these systems. We propose two new commit protocols for externalized commit DBMSs. The first may be used to obtain global commit in heterogeneous database systems composed of DBMSs with different 2-phase commit protocols (e.g., centralized and linear). The second protocol is more general, and ensures global commit even if the participating DBMSs employ 3-phase commit protocols. The more general protocol also preserves database autonomy, since it does not block a DBMS upon failure of another system. We describe both protocols in detail and prove their correctness. Recommended by: M. RusinkiewiczThis work was partially supported by an IBM Research Initiation Grant.     

Meningoencephalitis and brain abscessation due to Escherichia coli in a 2 week old alpaca cria

An alpaca cria which received insufficient colostrum, presented with lethargy, anorexia, no passage of faeces and neurological signs. Differential diagnosis included neonatal septicaemia, meningitis and gastrointestinal obstruction. The cria died despite treatment. Necropsy revealed brain abscesses with Escherichia Coli in pure culture. The importance of the amount and timing of colostrum intake is discussed.     

Fetal cardiac measurements derived by transvaginal and transabdominal cross-sectional echocardiography from 14 weeks of gestation to term

OBJECTIVE: Most of the routine ultrasound screening in our institution consists of early transvaginal examinations at 14-17 weeks. Complete fetal echocardiography is performed in every case. However, normal values for most fetal cardiac structures at this stage of gestation are not available. Our aim was to construct normal ranges for fetal cardiac structures, derived from cross-sectional echocardiography, at 14-40 weeks of gestation. DESIGN: A prospective study was performed. The study group consisted of 637 pregnant women referred for a routine sonographic examination. Women with abnormal prenatal or postnatal outcome were not included in the study. Transvaginal examinations were used for 14-17 weeks of gestation. More advanced pregnancies were examined transabdominally. RESULTS: We constructed normal ranges for the left and right end-diastolic transverse ventricular diameters (n = 637), left/right ventricular ratio (n = 637), aortic root diameter (n = 637), pulmonary artery diameter (n = 637), aortic/pulmonary ratio (n = 490), left and right transverse atrial diameters (n = 201) and left/right atrial ratio (n = 201). CONCLUSIONS: The results provide the examiner with normal ranges for fetal cardiac structures for the early transvaginal examination. The continuity of all curves from 14 to 40 weeks of gestation allows follow-up of any specific fetus to term.     

A wrinkle in time: a case study in DNS poisoning

International Journal of Information Security - The domain name system (DNS) provides a translation between readable domain names and IP addresses. The DNS is a key infrastructure component of the...     

Uncluttering Graph Layouts Using Anisotropic Diffusion and Mass Transport

Many graph layouts include very dense areas, making the layout difficult to understand. In this paper, we propose a technique for modifying an existing layout in order to reduce the clutter in dense areas. A physically inspired evolution process based on a modified heat equation is used to create an improved layout density image, making better use of available screen space. Using results from optimal mass transport problems, a warp to the improved density image is computed. The graph nodes are displaced according to the warp. The warp maintains the overall structure of the graph, thus limiting disturbances to the mental map, while reducing the clutter in dense areas of the layout. The complexity of the algorithm depends mainly on the resolution of the image visualizing the graph and is linear in the size of the graph. This allows scaling the computation according to required running times. It is demonstrated how the algorithm can be significantly accelerated using a graphics processing unit (GPU), resulting in the ability to handle large graphs in a matter of seconds. Results on several layout algorithms and applications are demonstrated.     

Online scheduling of two job types on a set of multipurpose machines with unit processing times

We study a problem of scheduling a set of n jobs with unit processing times on a set of m multipurpose machines in which the objective is to minimize the makespan. It is assumed that there are two different job types, where each job type can be processed on a unique subset of machines. We provide an optimal offline algorithm to solve the problem in constant time and an online algorithm with a competitive ratio that equals the lower bound. We show that the worst competitive ratio is obtained for an inclusive job-machine structure in which the first job type can be processed on any of the m machines while the second job type can be processed only on a subset of m/2 machines. Moreover, we show that our online algorithm is 1-competitive if the machines are not flexible, i.e., each machine can process only a single job type.