On the optimization of heap leaching

Although heap leaching has become established as the technology for treatment of some copper, gold, and zinc minerals, as well as its extension to the treatment of other types of minerals such as saltpeter and mine tailings, little study has been made on the optimization of this technology. Usually the operation of heap leaching is carried out until the maximum recovery has been obtained, or until observing that the concentration in the output solution of the heap exhibits no further extraction. The present study makes an analysis to determine if these criteria present the best conditions from the economic standpoint. Two variables are examined including, (1) leaching time, and (2) height of the heap, at a copper mineral treatment plant. The results of the study showed that the design (height of the heap), and planning of the operation (operational time) were interactive factors, and that maximum recovery was not necessarily the best measure of operational efficiency based on economic considerations.     

Finding the most unusual time series subsequence: algorithms and applications

In this work we introduce the new problem of finding time seriesdiscords. Time series discords are subsequences of longer time series that are maximally different to all the rest of the time series subsequences. They thus capture the sense of the most unusual subsequence within a time series. While discords have many uses for data mining, they are particularly attractive as anomaly detectors because they only require one intuitive parameter (the length of the subsequence) unlike most anomaly detection algorithms that typically require many parameters. While the brute force algorithm to discover time series discords is quadratic in the length of the time series, we show a simple algorithm that is three to four orders of magnitude faster than brute force, while guaranteed to produce identical results. We evaluate our work with a comprehensive set of experiments on diverse data sources including electrocardiograms, space telemetry, respiration physiology, anthropological and video datasets. Eamonn Keogh is an Assistant Professor of computer science at the University of California, Riverside. His research interests include data mining, machine learning and information retrieval. Several of his papers have won best paper awards, including papers at SIGKDD and SIGMOD. Dr. Keogh is the recipient of a 5-year NSF Career Award for “Efficient discovery of previously unknown patterns and relationships in massive time series databases.” Jessica Lin is an Assistant Professor of information and software engineering at George Mason University. She received her Ph.D. from the University of California, Riverside. Her research interests include data mining and informational retrieval. Sang-Hee Lee is a paleoanthropologist at the University of California, Riverside. Her research interests include the evolution of human morphological variation and how different mechanisms (such as taxonomy, sex, age, and time) explain what is observed in fossil data. Dr. Lee obtained her Ph.D. in anthropology from the University of Michigan in 1999. Helga Van Herle is an Assistant Clinical Professor of medicine at the Division of Cardiology of the Geffen School of Medicine at UCLA. She received her M.D. from UCLA in 1993; completed her residency in internal medicine at the New York Hospital (Cornell University, 1993–1996) and her cardiology fellowship at UCLA (1997–2001). Dr. Van Herle holds a M.Sc. in bioengineering from Columbia University (1987) and a B.Sc. in Chemical Engineering from UCLA (1985)     

Concerns about breast cancer and relations to psychosocial well-being in a multiethnic sample of early-stage patients.

Much work on psychosocial sequelae of breast cancer has been guided by the assumption that body image and partner reaction issues are focal. In a tri-ethnic sample of 223 women treated for early-stage breast cancer within the prior year, the authors assessed a wider range of concerns and relations to well-being. Strongest concerns were recurrence, pain, death, harm from adjuvant treatment, and bills. Body-image concerns were moderate; concern about rejection was minimal. Younger women had stronger sexual and partner-related concerns than older women. Hispanic women had many stronger concerns and more disruption than other women. Life and pain concerns and sexuality concerns contributed uniquely to predicting emotional and psychosexual disruption; life and pain concerns and rejection concerns contributed to predicting social disruption. In sum, adaptation to breast cancer is a process bearing on several aspects of the patient's life space. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cue-elicited negative affect in impulsive smokers.

Impulsivity is associated with cigarette smoking, but the nature of this relationship and the mechanisms that maintain it are relatively unknown. The relationship has often been thought to reflect appetitive processes, but research suggests that an affective pathway exists as well. The present study tested the effect of impulsivity on affective responses to an environmental smoking cue. Adult smokers (N=62) were exposed to a neutral cue and a smoking cue in separate experimental sessions in a repeated-measures design. Mixed-effects regression analyses showed that larger postexposure increases in negative affect were associated with high scores on 2 facets of impulsivity: urgency, t(179)=6.16, p     

The role of CA3 and CA1 in the acquisition of an object-trace-place paired-associate task.

The hippocampus mediates associative learning involving spatial and temporal information. Specifically, paired associations in which a trace interval separates the elements appear to be associated within CA1. In contrast, CA3 appears to be involved in associations containing spatial elements. This suggests that CA3, but not CA1, is involved as long as the spatial association does not contain temporal elements; conversely, CA1 is involved when a temporal element is included, regardless of whether there are spatial elements present. In the present study, rats were run on an object-trace-place paired-associate learning paradigm. Rats with CA3 as well as rats with CA1 lesions showed deficits in the acquisition of this task. These results suggest that CA1 is involved in making arbitrary associations involving a temporal (trace) element, whereas CA3 is involved in making associations that involve spatial elements; furthermore, CA1 and CA3 interact in the presence of both spatial and temporal information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representational momentum and Michotte's "launching effect" paradigm (1946/1963).

In A. Michotte's (1946/1963) launching effect, a moving launcher contacts a stationary target, and then the launcher becomes stationary and the target begins to move. In this experiment, observers viewed modifications of a launching effect display, and displacement in memory for the location of targets was measured. Forward displacement of targets in launching effect displays was decreased relative to that of targets (a) that were presented in isolation and either moved at a constant fast or slow velocity of decelerated or (b) that moved in a direction orthogonal to previous motion of the launcher. Possible explanations involving a deceleration of motion or landmark attraction effects were ruled out. Displacement patterns were consistent with naive impetus theory and the hypothesis that observers believed impetus from the launcher was imparted to the target and then dissipated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What men want: The role of reflective opposite-sex normative preferences in alcohol use among college women.

Misperceptions of peer drinking norms have been found to be strongly associated with individual drinking behavior, especially for proximal reference groups such as same-sex friends. Less studied are the effects of perceived preferences from the opposite sex on alcohol use; that is, the behaviors an individual believes the opposite sex prefers from them. Research suggests that these perceived “reflective” normative preferences may be particularly salient among college women, who may drink in pursuit of intimate relationships and positive attention from male peers. Heterosexual undergraduate students from two universities participated in this project. Females answered questions regarding the amount of alcohol they believe a typical male would like his female friends, dates, or romantic partners to drink. Males answered the same questions, stating their actual preferences. Results showed that females overestimate the amount of alcohol males want their female friends, dating partners, and sexual partners to drink, and that this misperception was associated with their drinking behavior, even after controlling for perceived same-sex norms. These results suggest that reflective normative feedback may offer a powerful new tool for female-targeted interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using workforce analysis to answer questions related to the internship imbalance and career pipeline in professional psychology.

This article defines workforce analysis and reviews the ongoing call for the field of psychology to address workforce analysis issues in a systematic manner. The American Psychological Association's progress in developing a workforce analysis capacity is traced, and the authors focus on how workforce analysis can be used to answer a series of questions regarding career pipeline issues, the supply of students and demand for internship training positions, and employment opportunities in professional psychology. The authors conclude that professional education and training issues can only be fully understood in the context of a databased approach to workforce demands for psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of 5-HT1A receptors in the behavioral responses associated with innate fear.

Fear is a response induced by threatening stimuli and represents an important adaptive system. The serotonin (5-HT) system has been shown to be involved in the modulation of fear responses and anxiety disorders. In preclinical studies, it has been demonstrated that R (+)-8-hydroxy-dipropylaminotetralin (8-OHDPAT), a 5-HT1A agonist, has anxiolytic properties. However, 8-OHDPATs potential role in unconditioned fear has yet to be elucidated. The current study was designed to investigate the effects of 8-OHDPAT on behavioral and HPA axis function in response to an innate fear-inducing stimulus. Pretreatment with 8-OHDPAT resulted in a significant decrease in freezing grooming, and climbing and caused a significant increase in approach after exposure to an extract from fox feces, 2,5-dihyrdo-2,4,5-trimethylthiazoline (TMT), an unconditioned fear-inducing stimulus. Furthermore, 8-OHDPAT pretreatment also resulted in a significant decrease in blood corticosterone levels, a marker of HPA activation. Taken together, these results suggest an additional anxyolitic-like effect of 8-OHDPAT in innate fear paradigms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)