An exemplar-based random walk model of speeded classification

The authors propose and test an exemplar-based random walk model for predicting response times in tasks of speeded, multidimensional perceptual classification. The model combines elements of R. M. Nosofsky's (1986) generalized context model of categorization and G. D. Logan's (1988) instance-based model of automaticity. In the model, exemplars race among one another to be retrieved from memory, with rates determined by their similarity to test items. The retrieved exemplars provide incremental information that enters into a random walk process for making classification decisions. The model predicts correctly effects of within- and between-categories similarity, individual-object familiarity, and extended practice on classification response times. It also builds bridges between the domains of categorization and automaticity.     

Random Vibration of Systems with Viscoelastic Memory

The equation of motion of linear dynamic systems with viscoelastic memory is usually expressed in a integrodifferential form, and its numerical solution is computationally heavy. In two recent papers, the writers suggested that the system memory be accounted for through the introduction of a number of additional internal variables. Following this approach, the motion of the system is governed by a set of first-order, linear differential equations, whose solution is quite easy. In this paper, the approach is extended to single-degree-of-freedom systems subjected to random, nonstationary excitation. The equations governing the time variation of the second-order statistics are derived, and an effective step-by-step solution procedure is proposed. Numerical example shows the accuracy of the procedure for white and nonwhite excitations.     

Multiconfiguration Dirac-Fock wavelengths and transition rates in the X-ray spectra of highly charged Ga-like ions from Yb to U

A multiconfiguration Dirac-Fock (MCDF) technique has been used for computing the wavelengths and transition probabilities for lines in the X-ray spectra of the gallium-like ions from Yb XL to U LXII. Results are presented for the 4s²4p-4s²4d and 4s²4p-4s4p² allowed transitions (E1) as well as for the forbidden transitions (M1 and E2) within the ground configuration 4s²4p. A comparison of the calculated wavelengths with the few experimental results available is also presented.     

Beneficial effects on water management of simple hydraulic structures in wetland systems: the Vallevecchia case study, Italy

Conflicting water uses in coastal zones demand integrated approaches to achieve sustainable water resources management, protecting water quality while allowing those human activities which rely upon aquatic ecosystem services to thrive. This case study shows that the creation and simple management of hydraulic structures within constructed wetlands can markedly reduce the non-point pollution from agriculture and, simultaneously, benefit agricultural activities, particularly during hot and dry periods. The Vallevecchia wetland system is based on a reclaimed 900 ha-large drainage basin in Northern Italy, where droughts recently impacted agriculture causing water scarcity and saltwater intrusion. Rainwater and drained water are recirculated inside the system to limit saltwater intrusion, provide irrigation water during dry periods and reduce the agricultural nutrient loads discharged into the bordering, eutrophic Adriatic Sea. Monitoring (2003-2009) of water quality and flows highlights that the construction (ended in 2005) of a gated spillway to control the outflow, and of a 200,000 m3 basin for water storage, dramatically increased the removal of nutrients within the system. Strikingly, this improvement was achieved with a minimal management effort, e.g., each year the storage basin was filled once: a simple management of the hydraulic structures would greatly enhance the system efficiency, and store more water to irrigate and limit saltwater intrusion.     

Hybrid prediction-optimization approaches for maximizing parts density in SLM of Ti6Al4V titanium alloy

Journal of Intelligent Manufacturing - It is well known that the processing parameters of selective laser melting (SLM) highly influence mechanical and physical properties of the manufactured...     

Cervical pregnancy: an obstetric emergency. A clinical case

Cervical implantation could develop in three different ways. The gestational sac can grow up to external os and interruption may simulate an abnormal menstruation. Theoretically the gestational sac could reach the uterine cavity, with a normal evolution of the pregnancy, even if the implantation of the placenta would be on internal uterine os. Lastly, the ectopic gestational sac developes all in cervical channel with an "obstetrical catastrophe". The incidence of cervical pregnancy presents great differences between authors, from 1:1,000 to 1:95,000 pregnancies; this is due to the variability of diagnostic criteria. A 36 year-old woman, para 1001, came to the emergency unit with painless vaginal bleeding. She was pregnant at 8 weeks of amenorrhoea, and previously undergone a cesarean section. The portio was swollen and bluewish, the external os was opened. The uterus was slightly increased, expecially in the peri-isthmic area; no adnexal mass. The urinary hCG was < 15,000 I.U. An ultrasound examination showed the endometrium in decidual transformation, without identification of embrional or extraembrional structures. The diagnosis was retained miscarriage. During the cervical dilatation, an impressive and uncontrollable haemorrhage occurred. It was decided to perform a total hysterectomy via laparotomy. The macroscopic examination of the uterus showed the cavity empty and the sopravaginal cervical area enlarged, invaded by an ectopic trophoblastic proliferation. The majority of obstetricians will never see a cervical pregnancy; the minority who has to treat this pathology wishes to have never seen one.     

Using a neural network for predicting the average grain size in friction stir welding processes

In the paper the microstructural phenomena in terms of average grain size occurring in friction stir welding (FSW) processes are focused. A neural network was linked to a finite element model (FEM) of the process to predict the average grain size values. The utilized net was trained starting from experimental data and numerical results of butt joints and then tested on further butt, lap and T-joints. The obtained results show the capability of the AI technique in conjunction with the FE tool to predict the final microstructure in the FSW joints.     

Wavelengths and transition probabilities for n = 4 → n′ = 4 transitions in heavy Cu-like ions (70 ? Z ? 92)

Wavelengths and transition probabilities have been calculated for the n = 4 → n′ = 4 allowed transitions in the heavy Cu-like ions with Z = 70-92. Fully relativistic multiconfiguration Dirac-Fock (MCDF) calculations were carried out. They take into account the correlations within the n = 4 complex, the core-valence n = 3 → n′ = 4 virtual excitations, and quantum electrodynamics effects. The present results are compared to and agree well with recent electron-beam ion-trap (EBIT) measurements in ytterbium, tungsten, osmium, gold, lead, bismuth, thorium, and uranium.     

Increase of trans-resveratrol in typical Sicilian wine using β-Glucosidase from various sources

β-Glucosidase (EC 3.2.1.21) (β-G) from different sources were tested to increase the trans-resveratrol in some Sicilian wines by hydrolysing resveratrol glucoside. β-G from Aspergillus niger mould was tested as a crude and purified enzyme, and compared with the same enzyme from Saccharomyces cerevisiae yeast. Specific purification served to eliminate collateral enzyme activities so that β-G could be used simply and economically. Aspergillus niger β-G produced trans-resveratrol increases of up to 75%, with no change in physico-chemical properties and bouquet, and an increase in health and nutritional properties. S. cerevisiae β-G raised free-terpenol levels, but impaired wine colour due to anthocyanase activity.