Impact of SRT on the performance of MBRs for the treatment of high strength landfill leachate

KAUST Repository

El-Fadel, M.

2017-12-14

This study examines the performance and fouling potential of flat sheet (FS) and hollow fiber (HF) membrane bioreactors (MBRs) during the treatment of high strength landfill leachate under varying solid retention times (SRT = 5–20 days). Mixed-liquor bacterial communities were examined over time using 16S rRNA gene sequence analysis in an attempt to define linkages between the system performance and the microbial community composition. Similarly, biofilm samples were collected at the end of each SRT to characterize the microbial communities that evolved on the surface of the FS and HF membranes. In general, both systems exhibited comparable removal efficiencies that dropped significantly as SRT was decreased down to 5 days. Noticeably, ammonia and nitrite oxidizing bacteria were not detected at the tested SRTs. This suggests that the nitrifiers were not enriched, possibly due to the high organic and ammonium content of the leachate that led to low TN and NH3 removal efficiency. The steady-state fouling rate of both membranes increased linearly with the decrease in SRT at an estimated factor of 1.1 and 1.2 for the FS- and HF-MBR, respectively, when the SRT was reduced from 15 to 10 days and from 10 to 5 days. Similar dominant genera were detected in both MBRs, including Pseudomonas, Aequorivita, Ulvibacter, Taibaiella, and Thermus. Aequorivita, Taibaiella; Thermus were the dominant genera in the biofilms. Hierarchical clustering and non-metric multidimensional scaling revealed that while the mixed liquor communities in the FS-MBR and HF-MBRs were dynamic, they clustered separately. Similarly, biofilm communities on the FS and HF membranes differed in the dynamic bacterial community structure, especially for the FS-MBR; however this was less dynamic than the mixed liquor community.

Improved production of short-chain fatty acids from waste activated sludge driven by carbohydrate addition in continuous-flow reactors: Influence of SRT and temperature

International Nuclear Information System (INIS)

Luo, Jingyang; Feng, Leiyu; Zhang, Wei; Li, Xiang; Chen, Hong; Wang, Dongbo; Chen, Yinguang

2014-01-01

Highlights: • SRT or temperature increase benefited the hydrolysis of fermentation substrates. • SCFAs, especially propionic acid, accumulated most at SRT 8 d and 37 °C. • The activities of key enzymes were in accordance with SCFAs production. • The ratio of Bacteria to Archaea was improved at SRT 8 d and 37 °C. - Abstract: During anaerobic fermentation of waste activated sludge (WAS), the production of short-chain fatty acids (SCFAs), especially propionic acid which is considered as the most preferred carbon source for enhanced biological phosphorus removal, can be improved by controlling the suitable mass ratio of carbon to nitrogen (C/N) and pH in batch mode. In this study the influences of solids retention time (SRT) and temperature on WAS hydrolysis and acidification in the continuous-flow systems in which the C/N ratio of WAS was modified by carbohydrate addition were investigated. Experimental results showed that the increase of SRT and temperature in a pertinent range benefited the hydrolysis of fermentation substrates and the accumulation of SCFAs, and SRT 8 d and temperature 37 °C were the most preferred conditions for the production of SCFAs, especially propionic acid. As there were more consumption of protein and carbohydrate and less production of methane at SRT 8 d and temperature 37 °C, more SCFAs were accumulated. Also, both the activities of key hydrolases and acid-forming enzymes and the ratio of acidogenic bacteria to methanogens showed good agreements with SCFAs production

Toward automated selective retina treatment (SRT): an optical microbubble detection technique

Science.gov (United States)

Seifert, Eric; Park, Young-Gun; Theisen-Kunde, Dirk; Roh, Young-Jung; Brinkmann, Ralf

2018-02-01

Selective retina therapy (SRT) is an ophthalmological laser technique, targeting the retinal pigment epithelium (RPE) with repetitive microsecond laser pulses, while causing no thermal damage to the neural retina, the photoreceptors as well as the choroid. The RPE cells get damaged mechanically by microbubbles originating, at the intracellular melanosomes. Beneficial effects of SRT on Central Serous Retinopathy (CSR) and Diabetic Macula Edema (DME) have already been shown. Variations in the transmission of the anterior eye media and pigmentation variation of RPE yield in intra- and inter- individual thresholds of the pulse energy required for selective RPE damage. Those selective RPE lesions are not visible. Thus, dosimetry-systems, designed to detect microbubbles as an indicator for RPE cell damage, are demanded elements to facilitate SRT application. Therefore, a technique based on the evaluation of backscattered treatment light has been developed. Data of 127 spots, acquired during 10 clinical treatments of CSR patients, were assigned to a RPE cell damage class, validated by fluorescence angiography (FLA). An algorithm has been designed to match the FLA based information. A sensitivity of 0.9 with a specificity close to 1 is achieved. The data can be processed within microseconds. Thus, the process can be implemented in existing SRT lasers with an automatic pulse wise increasing energy and an automatic irradiation ceasing ability to enable automated treatment close above threshold to prevent adverse effects caused by too high pulse energy. Alternatively, a guidance procedure, informing the treating clinician about the adequacy of the actual settings, is possible.

Initial clinical results of linac stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) for pituitary adenomas

International Nuclear Information System (INIS)

Mitsumori, Michihide; Shrieve, Dennis C.; Alexander, Eben; Kaiser, Ursula B.; Richardson, Gary E.; McL Black, Peter; Loeffler, Jay S.

1997-01-01

Purpose: To evaluate the initial clinical results of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) for pituitary adenomas with regard to tumor control and toxicity of the treatment, thus evaluate the feasibility of these technique for the treatment of pituitary adenomas. Subjects and Methods: 48 patients with either inoperable, recurrent or residual pituitary adenoma who underwent either SRS or SRT at the Brigham and Women's Hospital between 9/89 and 9/95 were analyzed. Of these, 18 received treatment with SRS, and 30 received SRT. SRS was contraindicated for the patients in whom the minimal distance of the target and optic chiasm or optic nerve was less than 5 mm. Patient characteristics were similar in the two groups, with the exception of tumor volume and previous irradiation. Median tumor volumes were 1.8 cm 3 and 7.7 cm 3 for SRS and SRT, respectively. Three of the SRS and none of the SRT patients had a history of previous external radiation therapy. Both SRS and SRT were performed by the use of dedicated stereotactic 6-MV linear accelerator with a treatment plan designed using a dedicated software. Doses were prescribed to the isodose distribution that covered the identified target. Dose and normalization used for SRS varied from 1000 cGy at 85 % isodose line to 1800 cGy at 80 % isodose line. For SRT patients, total dose of 4500 cGy was normalized at 90 or 95 % isodose line and this was delivered in 25 fractions of 180 cGy daily dose. Results: Local control: There was 1 case of local failure in each of SRS and SRT series (median follow up 42.5 months and 22 month, respectively). CNS adverse effects: There were 3 SRS cases in whom a ring enhancement in the temporal lobe was observed in follow-up MRI. (median follow up 32 months). Of these, one resolved spontaneously, whereas the other 2 lesion persisted and considered to be radiation necrosis. None of them required surgical intervention to date. These were observed in the

Contribution of sortase SrtA2 to Lactobacillus casei BL23 inhibition of Staphylococcus aureus internalization into bovine mammary epithelial cells.

Directory of Open Access Journals (Sweden)

Renata F S Souza

Full Text Available Probiotics have been considered as a promising strategy to prevent various diseases in both humans and animals. This approach has gained interest in recent years as a potential means to control bovine mastitis. In a previous study, we found that several L. casei strains, including BL23, were able to inhibit the internalization of S. aureus, a major etiologic agent of mastitis, into bovine mammary epithelial cells (bMEC. This antagonism required a direct contact between L. casei and bMEC or S. aureus, suggesting the inhibition relied on interactions between L. casei cell surface components and bMEC. In this study, we have investigated the impact of some candidates which likely influence bacteria host cell interactions. We have shown that L. casei BL23 fbpA retained its inhibitory potential, indicating that L. casei BL23 antagonism did not rely (solely on competition between S. aureus and L. casei fibronectin-binding proteins for adhesion to bMEC. We have then investigated the impact of four sortase mutants, srtA1, srtA2, srtC1 and srtC2, and a double mutant (srtA1-srtA2 on L. casei BL23 inhibitory potential. Sortases are responsible for the anchoring on the bacterial cell wall of LPXTG-proteins, which reportedly play an important role in bacteria-host cell interaction. All the srt mutants tested presented a reduced inhibition capacity, the most pronounced effect being observed with the srtA2 mutant. A lower internalization capacity of L. casei srtA2 into bMEC was also observed. This was associated with several changes at the surface of L. casei BL23 srtA2 compared to the wild type (wt strain, including altered abundance of some LPXTG- and moonlighting proteins, and modifications of cell wall structure. These results strongly support the role of sortase A2 in L. casei BL23 inhibition against S. aureus internalization. Deciphering the contribution of the cell surface components altered in srtA2 strain in the inhibition will require further

Modulation of EMG-EMG Coherence in a Choice Stepping Task

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Ippei Nojima

2018-02-01

Full Text Available The voluntary step execution task is a popular measure for identifying fall risks among elderly individuals in the community setting because most falls have been reported to occur during movement. However, the neurophysiological functions during this movement are not entirely understood. Here, we used electromyography (EMG to explore the relationship between EMG-EMG coherence, which reflects common oscillatory drive to motoneurons, and motor performance associated with stepping tasks: simple reaction time (SRT and choice reaction time (CRT tasks. Ten healthy elderly adults participated in the study. Participants took a single step forward in response to a visual imperative stimulus. EMG-EMG coherence was analyzed for 1000 ms before the presentation of the stimulus (stationary standing position from proximal and distal tibialis anterior (TA and soleus (SOL muscles. The main result showed that all paired EMG-EMG coherences in the alpha and beta frequency bands were greater in the SRT than the CRT task. This finding suggests that the common oscillatory drive to the motoneurons during the SRT task occurred prior to taking a step, whereas the lower value of corticospinal activity during the CRT task prior to taking a step may indicate an involvement of inhibitory activity, which is consistent with observations from our previous study (Watanabe et al., 2016. Furthermore, the beta band coherence in intramuscular TA tended to positively correlate with the number of performance errors that are associated with fall risks in the CRT task, suggesting that a reduction in the inhibitory activity may result in a decrease of stepping performance. These findings could advance the understanding of the neurophysiological features of postural adjustments in elderly individuals.

A coagulase-negative and non-haemolytic strain of Staphylococcus aureus for investigating the roles of SrtA in a murine model of bloodstream infection.

Science.gov (United States)

Wang, Lin; Bi, Chongwei; Wang, Tiedong; Xiang, Hua; Chen, Fuguang; Hu, Jinping; Liu, Bingrun; Cai, Hongjun; Zhong, Xiaobo; Deng, Xuming; Wang, Dacheng

2015-08-01

Sortase A (SrtA) is a cysteine transpeptidase and virulence factor from Staphylococcus aureus (S. aureus) that catalyses the attachment and display of surface proteins on the cell wall, thereby mediating bacterial adhesion to host tissues, host-cell entry and evasion of the immune response. As a result, SrtA has become an important target in the development of therapies for S. aureus infections. In this study, we used the new reference strain S. aureus Newman D2C to investigate the role of SrtA in a murine model of bloodstream infection, when the impact of coagulase and haemolysin is excluded. The results suggested that deletion of SrtA reduced the bacterial burden on the heart, liver and kidneys by blunting the host proinflammatory cytokine response at an early point in infection. Kidneys, but not heart or liver, formed abscesses on the sixth day following non-lethal infection, and this effect was diminished by SrtA mutation. These findings indicate that SrtA is a determining virulence factor in lethality and formation of renal abscesses in mice followed by S. aureus bloodstream infection. We have thus established a convenient in vitro and mouse model for developing SrtA-targeted therapeutic strategies. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Time scarcity and food choices: an overview.

Science.gov (United States)

Jabs, Jennifer; Devine, Carol M

2006-09-01

Time scarcity, the feeling of not having enough time, has been implicated in changes in food consumption patterns such as a decrease in food preparation at home, an increase in the consumption of fast foods, a decrease in family meals, and an increase in the consumption of convenience or ready-prepared foods. These food choices are associated with less healthful diets and may contribute to obesity and chronic health problems such as cardiovascular disease, diabetes, and cancer. In spite of the potential importance for health, there has been little study of how time scarcity influences people's food choices. This paper presents an overview of time issues related to food choices and discuss applications of time research for nutrition and health researchers, policy makers, and practitioners interested in food choice.

Factors influencing the latency of simple reaction time.

Science.gov (United States)

Woods, David L; Wyma, John M; Yund, E William; Herron, Timothy J; Reed, Bruce

2015-01-01

Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

Factors influencing the latency of simple reaction time

Directory of Open Access Journals (Sweden)

David L Woods

2015-03-01

Full Text Available Simple reaction time (SRT, the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by computer hardware and software used for SRT measurement. We developed a calibrated and temporally-precise SRT paradigm to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs. Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231 ms, 213 ms when corrected for hardware delays and increased significantly with age (0.55 ms/year, but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT was estimated by subtracting movement-initiation time, measured in a speeded finger-tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms. SRT latencies increased with age while SDT latencies did not. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in those from the Victorian era and that age-related increases in SRT latencies are due primarily to slowed motor output.

Factors influencing the latency of simple reaction time

Science.gov (United States)

Woods, David L.; Wyma, John M.; Yund, E. William; Herron, Timothy J.; Reed, Bruce

2015-01-01

Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output. PMID:25859198

Reverse chemomodulatory effects of the SIRT1 activators resveratrol and SRT1720 in Ewing's sarcoma cells: resveratrol suppresses and SRT1720 enhances etoposide- and vincristine-induced anticancer activity.

Science.gov (United States)

Sonnemann, Jürgen; Kahl, Melanie; Siranjeevi, Priyanka M; Blumrich, Annelie; Blümel, Lisa; Becker, Sabine; Wittig, Susan; Winkler, René; Krämer, Oliver H; Beck, James F

2016-01-01

SIRT1-activating compounds (STACs) may have potential in the management of cancer. However, the best-studied STAC, the naturally occurring compound resveratrol, is reported to have contradictory effects in combination chemotherapy regimens: It has been shown both to increase and to decrease the action of anticancer agents. To shed more light on this issue, we comparatively investigated the impact of resveratrol and the synthetic STAC SRT1720 on the responsiveness of Ewing's sarcoma (ES) cells to the chemotherapeutic drugs etoposide and vincristine. Because the effects of STACs can depend on the functionality of the tumor suppressor protein p53, we used three ES cell lines differing in their p53 status, i.e., wild-type p53 WE-68 cells, mutant p53 SK-ES-1 cells and p53 null SK-N-MC cells. Single agent and combination therapy effects were assessed by flow cytometric analyses of propidium iodide uptake and mitochondrial depolarization, by measuring caspase 3/7 activity and by gene expression profiling. When applied as single agents, both STACs were effective in ES cells irrespective of their p53 status. Strikingly, however, when applied in conjunction with cytostatic agents, the STACs displayed reverse effects: SRT1720 largely enhanced etoposide- and vincristine-induced cell death, while resveratrol inhibited it. Combination index analyses validated the antipodal impact of the STACs on the effectiveness of the chemotherapeutics. These findings suggest that the synthetic STAC SRT1720 may be useful to enhance the efficacy of anticancer therapy in ES. But they also suggest that the dietary intake of the natural STAC resveratrol may be detrimental during chemotherapy of ES.

A pilot randomized, placebo controlled, double blind phase I trial of the novel SIRT1 activator SRT2104 in elderly volunteers.

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Vincenzo Libri

Full Text Available SRT2104 has been developed as a selective small molecule activator of SIRT1, a NAD(+-dependent deacetylase involved in the regulation of energy homeostasis and the modulation of various metabolic pathways, including glucose metabolism, oxidative stress and lipid metabolism. SIRT1 has been suggested as putative therapeutic target in multiple age-related diseases including type 2 diabetes and dyslipidemias. We report the first clinical trial of SRT2104 in elderly volunteers.Oral doses of 0.5 or 2.0 g SRT2104 or matching placebo were administered once daily for 28 days. Pharmacokinetic samples were collected through 24 hours post-dose on days 1 and 28. Multiple pharmacodynamic endpoints were explored with oral glucose tolerance tests (OGTT, serum lipid profiles, magnetic resonance imaging (MRI for assessment of whole body visceral and subcutaneous fat, maximal aerobic capacity test and muscle 31P magnetic resonance spectroscopy (MRS for estimation of mitochondrial oxidative capacity.SRT2104 was generally safe and well tolerated. Pharmacokinetic exposure increased less than dose-proportionally. Mean Tmax was 2-4 hours with elimination half-life of 15-20 hours. Serum cholesterol, LDL levels and triglycerides decreased with treatment. No significant changes in OGTT responses were observed. 31P MRS showed trends for more rapid calculated adenosine diphosphate (ADP and phosphocreatine (PCr recoveries after exercise, consistent with increased mitochondrial oxidative phosphorylation.SRT2104 can be safely administered in elderly individuals and has biological effects in humans that are consistent with SIRT1 activation. The results of this study support further development of SRT2104 and may be useful in dose selection for future clinical trials in patients.ClinicalTrials.gov NCT00964340.

Response time patterns in a stated choice experiment

DEFF Research Database (Denmark)

Börjesson, Maria; Fosgerau, Mogens

2015-01-01

This paper studies how response times vary between unlabelled binary choice occasions in a stated choice (SC) experiment, with alternatives differing with respect to in-vehicle travel time and travel cost. The pattern of response times is interpreted as an indicator of the cognitive processes...... employed by the respondents when making their choices. We find clear signs of reference-dependence in response times in the form of a strong gain–loss asymmetry. Moreover, different patterns of response times for travel time and travel cost indicate that these attributes are processed in different ways...

Status report of the SRT radiotelescope control software: the DISCOS project

Science.gov (United States)

Orlati, A.; Bartolini, M.; Buttu, M.; Fara, A.; Migoni, C.; Poppi, S.; Righini, S.

2016-08-01

The Sardinia Radio Telescope (SRT) is a 64-m fully-steerable radio telescope. It is provided with an active surface to correct for gravitational deformations, allowing observations from 300 MHz to 100 GHz. At present, three receivers are available: a coaxial LP-band receiver (305-410 MHz and 1.5-1.8 GHz), a C-band receiver (5.7-7.7 GHz) and a 7-feed K-band receiver (18-26.5 GHz). Several back-ends are also available in order to perform the different data acquisition and analysis procedures requested by scientific projects. The design and development of the SRT control software started in 2004, and now belongs to a wider project called DISCOS (Development of the Italian Single-dish COntrol System), which provides a common infrastructure to the three Italian radio telescopes (Medicina, Noto and SRT dishes). DISCOS is based on the Alma Common Software (ACS) framework, and currently consists of more than 500k lines of code. It is organized in a common core and three specific product lines, one for each telescope. Recent developments, carried out after the conclusion of the technical commissioning of the instrument (October 2013), consisted in the addition of several new features in many parts of the observing pipeline, spanning from the motion control to the digital back-ends for data acquisition and data formatting; we brie y describe such improvements. More importantly, in the last two years we have supported the astronomical validation of the SRT radio telescope, leading to the opening of the first public call for proposals in late 2015. During this period, while assisting both the engineering and the scientific staff, we massively employed the control software and were able to test all of its features: in this process we received our first feedback from the users and we could verify how the system performed in a real-life scenario, drawing the first conclusions about the overall system stability and performance. We examine how the system behaves in terms of network

Simulation of reflecting surface deviations of centimeter-band parabolic space radiotelescope (SRT) with the large-size mirror

Science.gov (United States)

Kotik, A.; Usyukin, V.; Vinogradov, I.; Arkhipov, M.

2017-11-01

he realization of astrophysical researches requires the development of high-sensitive centimeterband parabolic space radiotelescopes (SRT) with the large-size mirrors. Constructively such SRT with the mirror size more than 10 m can be realized as deployable rigid structures. Mesh-structures of such size do not provide the reflector reflecting surface accuracy which is necessary for the centimeter band observations. Now such telescope with the 10 m diameter mirror is developed in Russia in the frame of "SPECTR - R" program. External dimensions of the telescope is more than the size of existing thermo-vacuum chambers used to prove SRT reflecting surface accuracy parameters under the action of space environment factors. That's why the numerical simulation turns out to be the basis required to accept the taken designs. Such modeling should be based on experimental working of the basic constructive materials and elements of the future reflector. In the article computational modeling of reflecting surface deviations of a centimeter-band of a large-sized deployable space reflector at a stage of his orbital functioning is considered. The analysis of the factors that determines the deviations - both determined (temperatures fields) and not-determined (telescope manufacturing and installation faults; the deformations caused by features of composite materials behavior in space) is carried out. The finite-element model and complex of methods are developed. They allow to carry out computational modeling of reflecting surface deviations caused by influence of all factors and to take into account the deviations correction by space vehicle orientation system. The results of modeling for two modes of functioning (orientation at the Sun) SRT are presented.

Multiple choices of time in quantum cosmology

International Nuclear Information System (INIS)

Małkiewicz, Przemysław

2015-01-01

It is often conjectured that a choice of time function merely sets up a frame for the quantum evolution of the gravitational field, meaning that all choices should be in some sense compatible. In order to explore this conjecture (and the meaning of compatibility), we develop suitable tools for determining the relation between quantum theories based on different time functions. First, we discuss how a time function fixes a canonical structure on the constraint surface. The presentation includes both the kinematical and the reduced perspective, and the relation between them. Second, we formulate twin theorems about the existence of two inequivalent maps between any two deparameterizations, a formal canonical and a coordinate one. They are used to separate the effects induced by choice of clock and other factors. We show, in an example, how the spectra of quantum observables are transformed under the change of clock and prove, via a general argument, the existence of choice-of-time-induced semiclassical effects. Finally, we study an example, in which we find that the semiclassical discrepancies can in fact be arbitrarily large for dynamical observables. We conclude that the values of critical energy density or critical volume in the bouncing scenarios of quantum cosmology cannot in general be at the Planck scale, and always need to be given with reference to a specific time function. (paper)

Mode choice endogeneity in value of travel time estimation

DEFF Research Database (Denmark)

Mabit, Stefan Lindhard; Fosgerau, Mogens

The current way to estimate value of travel time is to use a mode-specific sample and hence to estimate mode-specific value of travel times. This approach raises certain questions concerning how to generalise the values to a population. A problem would be if there is an uncontrolled sample...... selection mechanism. This is the case if there is correlation between mode choice and the value of travel time that is not controlled for by explanatory variables. What could confuse the estimated values is the difficulty to separate mode effects from user effect. An example would be the effect of income...... of travel time we use a stated choice dataset. These data include binary choice within mode for car and bus. The first approach is to use a probit model to model mode choice using instruments and then use this in the estimation of the value of travel time. The second approach is based on the use of a very...

Examining the stability of dual-task posture and reaction time measures in older adults over five sessions: a pilot study.

Science.gov (United States)

Jehu, Deborah A; Paquet, Nicole; Lajoie, Yves

2016-12-01

Improved performance may be inherent due to repeated exposure to a testing protocol. However, limited research has examined this phenomenon in postural control. The aim was to determine the influence of repeated administration of a dual-task testing protocol once per week for 5 weeks on postural sway and reaction time. Ten healthy older adults (67.0 ± 6.9 years) stood on a force plate for 30 s in feet apart and semi-tandem positions while completing simple reaction time (SRT) and choice reaction time (CRT) tasks. They were instructed to stand as still as possible while verbally responding as fast as possible to the stimuli. No significant differences in postural sway were shown over time (p > 0.05). A plateau in average CRT emerged as the time effect revealed longer CRT during session 1 compared to sessions 3-5 (p task context. Postural sway and SRT were stable over the 5 testing sessions, but variability of CRT continued to improve over time. These findings form a basis for future studies to examine performance-related improvements due to repeated exposure to a testing protocol in a dual-task setting.

The Sirt1 activator SRT1720 attenuates angiotensin II-induced atherosclerosis in apoE{sup −/−} mice through inhibiting vascular inflammatory response

Energy Technology Data Exchange (ETDEWEB)

Chen, Yi xi; Zhang, Man; Cai, Yuehua; Zhao, Qihui; Dai, Wenjian, E-mail: wjdai@126.com

2015-10-02

Activation of the silent mating type information regulation 2 homolog 1 (SIRT1) has been shown consistent antiinflammatory function. However, little information is available on the function of SIRT1 during Angiotensin II (AngII)-induced atherosclerosis. Here we report atheroprotective effects of sirt1 activation in a model of AngII-accelerated atherosclerosis, characterized by suppression pro-inflammatory transcription factors Nuclear transcription factor (NF)-κB and Signal Transducers and Activators of Transcription. (STAT) signaling pathway, and atherosclerotic lesion macrophage content. In this model, administration of the SIRT1 agonist SRT1720 substantially attenuated AngII-accelerated atherosclerosis with decreasing blood pressure and inhibited NF-κB and STAT3 activation, which was associated with suppression of inflammatory factor and atherogenic gene expression in the artery. In vitro studies demonstrated similar changes in AngII-treated VSMCs and macrophages: SIRT1 activation inhibited the expression levels of proinflammatory factor. These studies uncover crucial proinflammatory mechanisms of AngII and highlight actions of SIRT1 activation to inhibit AngII signaling, which is atheroprotective. - Highlights: • SRT1720 reduced atherosclerotic lesion size in aortic arches and atherosclerotic lesion macrophage content. • SRT1720 could inhibit the phosphorylation of STAT3 and p65 phosphorylation and translocation. • SRT1720 could inhibit the expression of proinflammatory factor.

The influence of gymnastics in motor coordination and reaction time in urban public bus drivers

Directory of Open Access Journals (Sweden)

Stela Paula Mezzomo

2014-12-01

Full Text Available This study investigated the influence of labour gymnastics (LG on bus drivers' basic skills such as reaction time and gross motor coordination. Sixty male bus drivers (37.06 ± 7.66 years old from two bus lines in the city of Santa Maria (RS took part of this study. The participants were split into two groups, experimental group (EG and control group (CG. Subjects that were part of the EG took part in a LG intervention program, 2-3 times a week, over a year. Gross motor coordination was assessed by BURPEE Protocol (Johnson & Nelson, 1979, whereas reaction time by software providing a visual stimulus. Data normality was checked through Shapiro-Wilk test, which pointed to normal distribution only for the variables simple reaction time (SRT and choice reaction time (CRT in the EG. Therefore the non-parametric Mann-Whitney U test was selected to compare differences between groups. A statistically significant difference for gross motor coordination was found (z= −2.525, p= 0.012, suggesting the effectiveness of LG to improve motor skills. As regards SRT and CRT, no significant difference was found, in spite of better outcomes having been recorded after the LG program.

Factors that influence beverage choices at meal times

DEFF Research Database (Denmark)

Mueller Loose, Simone; Jaeger, S. R.

2012-01-01

Beverages are consumed at almost every meal occasion, but knowledge about the factors that influence beverage choice is less than for food choice. The aim of this research was to characterize and quantify factors that influence beverage choices at meal times. Insights into what beverages are chosen...... consumers. Participants (n=164) described 8356 meal occasions in terms of foods and beverages consumed, and the contextual characteristics of the occasion. Beverage choice was explored with random-parameter logit regressions to reveal influences linked to food items eaten, context factors and person factors....... Thereby this study contributed to the food choice kaleidoscope research approach by expressing the degree of context dependency in form of odds ratios and according significance levels. The exploration of co-occurrence of beverages with food items suggests that beverage-meal item combinations can be meal...

The effect of perceived mobility necessity in the choice of departure time

DEFF Research Database (Denmark)

Thorhauge, Mikkel; Cherchi, Elisabetta; Rich, Jeppe

2014-01-01

is likely to affect the choice of departure time. However departure time choice is also related to the full daily activity pattern, such as a restriction or a preference in one activity may form restrictions in the flexibility of other activities and thereby affect the preference for the related departure...... time. In this paper we investigate how the latent effect of the perceived mobility necessities affects the choice of departure time. A stated choice experiment collected among workers who commute to Copenhagen center is used to estimate 9 hybrid choice models where the discrete choice of departing...... before or later than the current trip depends on the latent construct of the perceived mobility necessities. Results show that individuals who perceive they have high mobility necessity tend to prefer the current departure time, and in particular dislike departing later. However the latent variables...

Experiments at SRT Using the NOAA CrIS/ATMS Proxy Data Set

Science.gov (United States)

Susskind, Joel; Kouvaris, Louis; Iredell, Lena

2011-01-01

The objectives of the talk are: (1) Assess the performance of NGAS Version-1.5.03.00 CrIS/ATMS retrieval algorithm as delivered by LaRC, modified to include the MW and IR tuning coefficients and new CrIS noise model (a) Percent acceptance (b) RMS and mean differences of T(p) vs. ECMWF truth as a function of % yield (2) Compare performance of NGAS retrieval algorithm with an AIRS Science Team Version-6 like retrieval algorithm modified at Sounder Research Team (SRT) for CrIS/ATMS

SU-E-T-536: LINAC-Based Single Isocenter Frameless SRT for Brain Metastases

International Nuclear Information System (INIS)

Liu, B; Zhang, L; Rigor, N; Kim, J

2015-01-01

Purpose: Single-isocenter Stereotactic Radiotherapy of multiple brain metastases with Varian 21 IX LINAC, using Aktina Pinpoint system for patient setup. Methods: In 2014, five single-isocenter RapidArc SRT plans were delivered to five patients with 2 to 8 brain metastases using Varian 21 IX. Aktina Pinpoint system was used for setup and 2mm PTV margin were used. CBCT was acquired before and after the beam delivery. The prescription is 2100 cGy in 3 fractions. Eclipse planning system was used for treatment planning. Depending on the number of metastases and their locations, 1 to 5 coplanar or non coplanar arcs were used. Typically, 2 or 3 arcs are used. IMRT QAs were performed by comparing an A1SL ion chamber point dose measurement in solid water phantom to point dose of the plan; also, based on EPID measurement, 3D spatial dose was calculated using DosimetryCheck software package from MathResolutions Inc. The EPID system has an active area of 40cm by 30cm with 1024 by 768 photodiodes, which corresponds to a resolution of 0.4mm by 0.4mm pixel dimension. Results: for all the plans, at least 95% PTV coverage was achieved for full prescription dose, with plan normalization > 75%. RTOG conformity indices are less than 1.1 and Paddick gradient indices are less than 4.5. The distance from prescription IDL to 50% IDL increases as the number of metastases increases, and it ranges from 0.6mm to 0.8mm. Treatment time varies from 10mins to 30mins, depending on the number of arcs and if the arcs are coplanar. IMRT QA shows that the ion chamber measurement agree with the eclipse calculation within 3%, and 95% of the points passed Gamma, using 3% dose difference and 3mm DTA Conclusion: High quality single isocenter RapidArc SRT plan can be optimized and accurately delivered using Eclipse and Varian 21IX

Impact of sludge retention time on sludge characteristics and microbial community in MBR.

Science.gov (United States)

Su, Yuchun; Pan, Jill Ruhsing; Huang, Chihpin; Chang, Chialing

2011-01-01

In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.

Factoring out nondecision time in choice reaction time data: Theory and implications.

Science.gov (United States)

Verdonck, Stijn; Tuerlinckx, Francis

2016-03-01

Choice reaction time (RT) experiments are an invaluable tool in psychology and neuroscience. A common assumption is that the total choice response time is the sum of a decision and a nondecision part (time spent on perceptual and motor processes). While the decision part is typically modeled very carefully (commonly with diffusion models), a simple and ad hoc distribution (mostly uniform) is assumed for the nondecision component. Nevertheless, it has been shown that the misspecification of the nondecision time can severely distort the decision model parameter estimates. In this article, we propose an alternative approach to the estimation of choice RT models that elegantly bypasses the specification of the nondecision time distribution by means of an unconventional convolution of data and decision model distributions (hence called the D*M approach). Once the decision model parameters have been estimated, it is possible to compute a nonparametric estimate of the nondecision time distribution. The technique is tested on simulated data, and is shown to systematically remove traditional estimation bias related to misspecified nondecision time, even for a relatively small number of observations. The shape of the actual underlying nondecision time distribution can also be recovered. Next, the D*M approach is applied to a selection of existing diffusion model application articles. For all of these studies, substantial quantitative differences with the original analyses are found. For one study, these differences radically alter its final conclusions, underlining the importance of our approach. Additionally, we find that strongly right skewed nondecision time distributions are not at all uncommon. (c) 2016 APA, all rights reserved).

Waste activated sludge fermentation: effect of solids retention time and biomass concentration.

Science.gov (United States)

Yuan, Q; Sparling, R; Oleszkiewicz, J A

2009-12-01

Laboratory scale, room temperature, semi-continuous reactors were set-up to investigate the effect of solids retention time (SRT, equal to HRT hydraulic retention time) and biomass concentration on generation of volatile fatty acids (VFA) from the non-methanogenic fermentation of waste activated sludge (WAS) originating from an enhanced biological phosphorus removal process. It was found that VFA yields increased with SRT. At the longest SRT (10d), improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield from the influent COD (0.14g VFA-COD/g TCOD). It was also observed that under the same SRT, VFA yields increased when the biomass concentration decreased. At a 10d SRT the VFA yield increased by 46%, when the biomass concentration decreased from 13g/L to 4.8g/L. Relatively high nutrient release was observed during fermentation. The average phosphorus release was 17.3mg PO(4)-P/g TCOD and nitrogen release was 25.8mg NH(4)-N/g TCOD.

Defining biochemical recurrence after radical prostatectomy and timing of early salvage radiotherapy. Informing the debate

International Nuclear Information System (INIS)

Budaeus, Lars; Schiffmann, Jonas; Graefen, Markus; Huland, Hartwig; Tennstedt, Pierre; Siegmann, Alessandra; Boehmer, Dirk; Budach, Volker; Bartkowiak, Detlef; Wiegel, Thomas

2017-01-01

The optimal prostate-specific antigen (PSA) level after radical prostatectomy (RP) for defining biochemical recurrence and initiating salvage radiation therapy (SRT) is still debatable. Whereas adjuvant or extremely early SRT irrespective of PSA progression might be overtreatment for some patients, SRT at PSA >0.2 ng/ml might be undertreatment for others. The current study addresses the optimal timing of radiation therapy after RP. Cohort 1 comprised 293 men with PSA 0.1-0.19 ng/ml after RP. Cohort 2 comprised 198 men with SRT. PSA progression and metastases were assessed in cohort 1. In cohort 2, we compared freedom from progression according to pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml). Multivariable Cox regression analyses predicted progression after SRT. In cohort 1, 281 (95.9%) men had further PSA progression ≥0.2 ng/ml and 27 (9.2%) men developed metastases within a median follow-up of 74.3 months. In cohort 2, we recorded improved freedom from progression according to lower pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml: 69 vs. 53%; log-rank p = 0.051). Patients with higher pre-SRT PSA ≥0.2 ng/ml were at a higher risk of progression after SRT (hazard ratio: 1.8; p [de

Factors that influence beverage choices at meal times. An application of the food choice kaleidoscope framework.

Science.gov (United States)

Mueller Loose, S; Jaeger, S R

2012-12-01

Beverages are consumed at almost every meal occasion, but knowledge about the factors that influence beverage choice is less than for food choice. The aim of this research was to characterize and quantify factors that influence beverage choices at meal times. Insights into what beverages are chosen by whom, when and where can be helpful for manufacturers, dieticians/health care providers, and health policy makers. A descriptive framework - the food choice kaleidoscope (Jaeger et al., 2011) - was applied to self-reported 24h food recall data from a sample of New Zealand consumers. Participants (n=164) described 8356 meal occasions in terms of foods and beverages consumed, and the contextual characteristics of the occasion. Beverage choice was explored with random-parameter logit regressions to reveal influences linked to food items eaten, context factors and person factors. Thereby this study contributed to the food choice kaleidoscope research approach by expressing the degree of context dependency in the form of odds ratios and according significance levels. The exploration of co-occurrence of beverages with food items suggests that beverage-meal item combinations can be meal specific. Furthermore, this study integrates psychographic variables into the 'person' mirror of the food choice kaleidoscope. A measure of habit in beverage choice was obtained from the inter-participant correlation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Departure time choice: Modelling individual preferences, intention and constraints

DEFF Research Database (Denmark)

Thorhauge, Mikkel

by nearly all studies within departure time. More importantly it shows that the underlying psychological processes are more complex than simply accounting for attitudes and perceptions which are typically used in other areas. The work in this PhD thesis accounts for the full Theory of Planned Behaviour......, but can also be perceived by the individuals as barriers towards participating in activities. Perceived constraints affect the departure time choice through the individual intention of being on time. This PhD thesis also contributes to the departure time literature by discussing the problem of collecting...... whether they are constrained. The thesis also provides empirical evidences of the policy implication of not accounting for other activities and their constraints. Thirdly, the thesis shows that the departure time choice can be partly explained by psychological factors, which have previously been neglected...

Influence of time orientation on food choice: Case study with cookie labels.

Science.gov (United States)

Tórtora, Giuliana; Ares, Gastón

2018-04-01

Time orientation can influence health-related behaviors, including food consumption. The aim of the present work was to study the influence of time orientation on food choice, using cookie labels as case study. A choice-conjoint task was designed using labels differing in type of cookie (chocolate chips vs. granola), front-of-pack nutrition information (nutritional warnings vs. Facts Up Front system) and nutritional claim (no claim vs. "0% cholesterol. 0% trans fat"). An online study was conducted, in which 155 participants evaluated 8 pairs of cookie labels and selected the one they would buy if they were in the supermarket. Then, they were asked to complete a consideration of future consequences scale (CFC) adapted to eating habits, as well as a questionnaire about socio-demographic characteristics. Time orientation influenced participants' choices of cookies labels; particularly the importance attached to type of cookie. Participants with greater consideration of future consequences preferred the granola cookies, associated with health, while those who prioritized immediate consequences preferred chocolate chip cookies. In addition, nutritional warnings discouraged choice regardless of participants' time orientation. Results from the present work provide additional evidence of the influence of time preferences on food choices and suggest that strategies to stimulate and generate a more future-oriented perspective on eating habits could contribute to more healthful food choices. Copyright © 2018 Elsevier Ltd. All rights reserved.

The homogeneity of audibility and prosody of Zulu words for speech reception threshold (SRT) testing.

Science.gov (United States)

Panday, Seema; Kathard, Harsha; Pillay, Mershen; Govender, Cyril

2009-01-01

The aim of this investigation was to determine which of 58 preselected Zulu words developed by Panday et al. (2007) could be used for Speech Reception Threshold (SRT) testing. To realize this aim the homogeneity of audibility of 58 bisyllabic Zulu low tone verbs was measured, followed by an analysis of the prosodic features of the selected words. The words were digitally recorded by a Zulu first language male speaker and presented at 6 intensity levels to 30 Zulu first language speakers (18-25 years, mean age of 21.5 years), whose hearing was normal. Homogeneity of audibility was determined by employing logistic regression analysis. Twenty eight words met the criterion of homogeneity of audibility. This was evidenced by a mean slope of 50% at 5.98%/dB. The prosodic features of the twenty eight words were further analyzed using a computerized speech laboratory system. The findings confirmed that the pitch contours of the words followed the prosodic pattern apparent within Zulu linguistic structure. Eighty nine percent of the Zulu verbs were found to have a difference in the pitch pattern between the two syllables i.e. the first syllable was low in pitch, while the second syllable was high in pitch. It emerged that the twenty eight words could be used for establishing SRT within a normal hearing Zulu speaking population. Further research within clinical populations is recommended.

SRTC criticality safety technical review of SRT-CMA-930039

International Nuclear Information System (INIS)

Rathbun, R.

1993-01-01

Review of SRT-CMA-930039, ''Nuclear Criticality Safety Evaluation (NCSE): DWPF Melter-Batch 1,'' December 1, 1993, has been performed by the Savannah River Technical Center (SRTC) Applied Physics Group. The NCSE is a criticality assessment of the Melt Cell in the DWPF. Additionally, this pertains only to Batch 1 operation, which differs from batches to follow. Plans for subsequent batch operations call for fissile material in the Salt Cell feed-stream, which necessitates a separate criticality evaluation in the future. The NCSE under review concludes that the process is safe from criticality events, even in the event that all lithium and boron neutron poisons are lost, provided uranium enrichments are less than 40%. Furthermore, if all the lithium and as much as 98% of the boron would be lost, uranium enrichments of 100% would be allowable. After a thorough review of the NCSE, this reviewer agrees with that conclusion. This technical review consisted of: an independent check of the methods and models employed, independent calculations application of ANSI/ANS 8.1, verification of WSRC Nuclear Criticality Safety Manual( 2 ) procedures

Kinetic modeling of the effect of solids retention time on methanethiol dynamics in anaerobic digestion.

Science.gov (United States)

Zhang, Dian; Strawn, Mary; Novak, John T; Wang, Zhi-Wu

2018-07-01

The highly volatile methanethiol (MT) with an extremely low odor threshold and distinctive putrid smell is often identified as a major odorous compound generated under anaerobic conditions. As an intermediate compound in the course of anaerobic digestion, the extent of MT emission is closely related to the time of anaerobic reaction. In this study, lab-scale anaerobic digesters were operated at solids retention time (SRTs) of 15, 20, 25, 30, 40 and 50 days to investigate the effect of SRT on MT emission. The experimental results demonstrated a bell-shaped curve of MT emission versus SRT with a peak around 20 days SRT. In order to understand this SRT effect, a kinetic model was developed to describe MT production and utilization dynamics in the course of anaerobic digestion and calibrated with the experimental results collected from this study. The model outcome revealed that the high protein content in the feed sludge together with the large maintenance coefficient of MT fermenters are responsible for the peak MT emission emergence in the range of typical SRT used for anaerobic digestion. A further analysis of the kinetic model shows that it can be extensively simplified with reasonable approximation to a form that anaerobic digestion practitioners could easily use to predict the MT and SRT relationship. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling effects of DO and SRT on activated sludge decay and production.

Science.gov (United States)

Liu, Guoqiang; Wang, Jianmin

2015-09-01

The effect of dissolved oxygen (DO) on the endogenous decay of active heterotrophic biomass and the hydrolysis of cell debris were studied. With the inclusion of a hydrolysis process for the cell debris, mathematical models that are capable of quantifying the effects of DO and sludge retention time (SRT) on concentrations of active biomass and cell debris in activated sludge are presented. By modeling the biomass cultivated with unlimited DO, the values of endogenous decay coefficient for heterotrophic biomass, the hydrolysis constant of cell debris, and the fraction of decayed biomass that became cell debris were determined to be 0.38 d(-1), 0.013 d(-1), and 0.28, respectively. Results from modeling the biomass cultivated under different DO conditions suggested that the experimental low DO (∼0.2 mg/L) did not inhibit the endogenous decay of heterotrophic biomass, but significantly inhibited the hydrolysis of cell debris with a half-velocity constant value of 2.1 mg/L. Therefore, the increase in sludge production with low DO was mainly contributed by cell debris rather than the active heterotrophic biomass. Maximizing sludge production during aerobic wastewater treatment could reduce aeration energy consumption and improve biogas energy recovery potential. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of low solids retention time and focused pulsed pre-treatment on anaerobic digestion of waste activated sludge.

Science.gov (United States)

Lee, Il-Su; Rittmann, Bruce E

2011-02-01

The interacting effects of Focused Pulsed (FP) treatment and solids retention time (SRT) were evaluated in laboratory-scale digesters operated at SRTs of 2-20 days. Anaerobic digestion and methanogenesis of waste activated sludge (WAS) were stable for SRT ≥ 5 days, but the effluent soluble organic compounds increased significantly for SRT=2 days due to a combination of faster hydrolysis kinetics and washout of methanogens. FP treatment increased the CH(4) production rate and TCOD removal efficiency by up to 33% and 18%, respectively, at a SRT of 20 days. These effects were the result of an increase in the hydrolysis rate, since the concentrations of soluble components remained low for SRT ≥ 5 days. Alternately, FP pre-treatment of WAS allowed the same conversion of TCOD to CH(4) with a smaller SRT and digester size: e.g., 40% size savings with a CH(4) conversion of 0.23 g CH(4)-COD/g COD(in). Copyright © 2010 Elsevier Ltd. All rights reserved.

The influence of time of day on decision fatigue in online food choice experiments

DEFF Research Database (Denmark)

Olsen, Søren Bøye; Meyerhoff, Jürgen; Mørkbak, Morten Raun

2017-01-01

is linked with knowledge from a food sociology survey on typical meal times as well as biophysical research linking food intake to blood sugar and mental energy in order to generate a proxy variable for each respondent’s level of mental energy when answering the food choice tasks in the questionnaire......Purpose: Fatigue effects related to answering a sequence of choice tasks have received much scrutiny in the stated choice experiments (SCE) literature. However, decision fatigue related to the time of day when respondents answer questionnaires has been largely overlooked in this literature even...... though time of day related fatigue effects are well known in the psychology literature. The purpose of this paper is to hypothesize that variations in the time of day when respondents answer an online food choice experiment will translate into observable fatigue effects in the food choices. Design...

Accounting for the Theory of Planned Behaviour in departure time choice

DEFF Research Database (Denmark)

Thorhauge, Mikkel; Haustein, Sonja; Cherchi, Elisabetta

2016-01-01

into a discrete choice model. The psychological factors were measured based on an online questionnaire addressed to car commuters to the city centre of Copenhagen (N = 286). The questionnaire additionally included a travel diary and a stated preference experiment with nine departure time choice scenarios. All...

Effect of solids retention time and wastewater characteristics on biological phosphorus removal

DEFF Research Database (Denmark)

Henze, Mogens; Aspegren, H.; Jansen, J.l.C.

2002-01-01

with time which has importance in relation to modelling. The overall conclusion of the comparison between the two plants is that the biological phosphorus removal efficiency under practical operating conditions is affected by the SRT in the plant and the wastewater composition. Thus great care should......The paper deals with the effect of wastewater, plant design and operation in relation to biological nitrogen and phosphorus removal and the possibilities to model the processes. Two Bio-P pilot plants were operated for 2.5 years in parallel receiving identical wastewater. The plants had SRT of 4...... and 21 days, the latter had nitrification and denitrification. The plant with 4 days SRT had much more variable biomass characteristics, than the one with the high SRT. The internal storage compounds, PHA, were affected significantly by the concentration of fatty acids or other easily degradable organics...

The effects of repeated testing, simulated malingering, and traumatic brain injury on high-precision measures of simple visual reaction time

Directory of Open Access Journals (Sweden)

David L Woods

2015-11-01

Full Text Available Simple reaction time (SRT, the latency to respond to a stimulus, has been widely used as a basic measure of processing speed. In the current experiments, we examined clinically-relevant properties of a new SRT test that presents visual stimuli to the left or right hemifield at varying stimulus onset asynchronies. Experiment 1 examined test-retest reliability in participants who underwent three test sessions at weekly intervals. In the first test, log-transformed (log-SRT z-scores, corrected for the influence of age and computer-use, were well predicted by regression functions derived from a normative population of 189 control participants. Test-retest reliability of log-SRT z-scores was measured with an intraclass correlation coefficient (ICC = 0.83 and equaled or exceeded those of other SRT tests and other widely used tests of processing speed that are administered manually. No significant learning effects were observed across test sessions. Experiment 2 investigated the same participants when instructed to malinger during a fourth testing session: 94% showed abnormal log-SRT z-scores, with 83% producing log-SRT z-scores exceeding a cutoff of 3.0, a degree of abnormality never seen in full-effort conditions. Thus, a log-SRT z-score cutoff of 3.0 had a sensitivity (83% and specificity (100% that equaled or exceeded that of existing symptom validity tests. We argue that even expert malingerers, fully informed of the malingering-detection metric, would be unable to successfully feign impairments on the SRT test because of the precise control of SRT latencies that would be required. Experiment 3 investigated 26 patients with traumatic brain injury (TBI tested more than one year post-injury. The 22 patients with mild TBI showed insignificantly faster SRTs than controls, but a small group of four patients with severe TBI showed slowed SRTs. Simple visual reaction time is a reliable measure of processing speed that is sensitive to the effects of

Defining biochemical recurrence after radical prostatectomy and timing of early salvage radiotherapy. Informing the debate

Energy Technology Data Exchange (ETDEWEB)

Budaeus, Lars; Schiffmann, Jonas; Graefen, Markus; Huland, Hartwig; Tennstedt, Pierre [University Medical Center Hamburg-Eppendorf, Martini-Clinic, Prostate Cancer Center, Hamburg (Germany); Siegmann, Alessandra; Boehmer, Dirk; Budach, Volker [Charite University Hospital, Department of Radiation Oncology, Berlin (Germany); Bartkowiak, Detlef; Wiegel, Thomas [University Hospital Ulm, Department of Radiation Oncology, Ulm (Germany)

2017-09-15

The optimal prostate-specific antigen (PSA) level after radical prostatectomy (RP) for defining biochemical recurrence and initiating salvage radiation therapy (SRT) is still debatable. Whereas adjuvant or extremely early SRT irrespective of PSA progression might be overtreatment for some patients, SRT at PSA >0.2 ng/ml might be undertreatment for others. The current study addresses the optimal timing of radiation therapy after RP. Cohort 1 comprised 293 men with PSA 0.1-0.19 ng/ml after RP. Cohort 2 comprised 198 men with SRT. PSA progression and metastases were assessed in cohort 1. In cohort 2, we compared freedom from progression according to pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml). Multivariable Cox regression analyses predicted progression after SRT. In cohort 1, 281 (95.9%) men had further PSA progression ≥0.2 ng/ml and 27 (9.2%) men developed metastases within a median follow-up of 74.3 months. In cohort 2, we recorded improved freedom from progression according to lower pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml: 69 vs. 53%; log-rank p = 0.051). Patients with higher pre-SRT PSA ≥0.2 ng/ml were at a higher risk of progression after SRT (hazard ratio: 1.8; p < 0.05). The vast majority of patients with PSA ≥0.1 ng/ml after RP will progress to PSA ≥0.2 ng/ml. Additionally, early administration of SRT at post-RP PSA level <0.2 ng/ml might improve freedom from progression. Consequently, we suggest a PSA threshold of 0.1 ng/ml to define biochemical recurrence after RP. (orig.) [German] Der optimale Wert des prostataspezifischen Antigens (PSA) nach radikaler Prostatektomie (RP) zur Definition eines biochemischen Rezidivs und zur Initiierung einer Salvage-Strahlentherapie (SRT) ist noch immer umstritten. Waehrend eine adjuvante oder extrem fruehe SRT unabhaengig vom PSA-Verlauf fuer einige Patienten eine Uebertherapie bedeuten wuerde, waere eine SRT bei einem PSA >0,2 ng/ml fuer andere eine Untertherapie. In der vorliegenden Studie wird der optimale

An investigation of leg and trunk strength and reaction times of hard-style martial arts practitioners.

Science.gov (United States)

Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H; Strutton, Paul H

2006-01-01

The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key PointsMartial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only.The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly.The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time

Evaluation of heterogeneity dose distributions for Stereotactic Radiotherapy (SRT: comparison of commercially available Monte Carlo dose calculation with other algorithms

Directory of Open Access Journals (Sweden)

Takahashi Wataru

2012-02-01

Full Text Available Abstract Background The purpose of this study was to compare dose distributions from three different algorithms with the x-ray Voxel Monte Carlo (XVMC calculations, in actual computed tomography (CT scans for use in stereotactic radiotherapy (SRT of small lung cancers. Methods Slow CT scan of 20 patients was performed and the internal target volume (ITV was delineated on Pinnacle3. All plans were first calculated with a scatter homogeneous mode (SHM which is compatible with Clarkson algorithm using Pinnacle3 treatment planning system (TPS. The planned dose was 48 Gy in 4 fractions. In a second step, the CT images, structures and beam data were exported to other treatment planning systems (TPSs. Collapsed cone convolution (CCC from Pinnacle3, superposition (SP from XiO, and XVMC from Monaco were used for recalculating. The dose distributions and the Dose Volume Histograms (DVHs were compared with each other. Results The phantom test revealed that all algorithms could reproduce the measured data within 1% except for the SHM with inhomogeneous phantom. For the patient study, the SHM greatly overestimated the isocenter (IC doses and the minimal dose received by 95% of the PTV (PTV95 compared to XVMC. The differences in mean doses were 2.96 Gy (6.17% for IC and 5.02 Gy (11.18% for PTV95. The DVH's and dose distributions with CCC and SP were in agreement with those obtained by XVMC. The average differences in IC doses between CCC and XVMC, and SP and XVMC were -1.14% (p = 0.17, and -2.67% (p = 0.0036, respectively. Conclusions Our work clearly confirms that the actual practice of relying solely on a Clarkson algorithm may be inappropriate for SRT planning. Meanwhile, CCC and SP were close to XVMC simulations and actual dose distributions obtained in lung SRT.

Manual Choice Reaction Times in the Rate-Domain

Directory of Open Access Journals (Sweden)

Chris eHarris

2014-06-01

Full Text Available Over the last 150 years, human manual reaction times (RTs have been recorded countless times. Yet, our understanding of them remains remarkably poor. RTs are highly variable with positively skewed frequency distributions, often modelled as an inverse Gaussian distribution reflecting a stochastic rise to threshold (diffusion process. However, latency distribution of saccades are very close to the reciprocal Normal, suggesting that ‘rate’ (reciprocal RT may be the more fundamental variable. We explored whether this phenomenon extends to choice manual RTs. We recorded two-alternative choice RTs from 24 subjects, each with 4 blocks of 200 trials with two task difficulties (easy vs. difficult discrimination and two instruction sets (urgent vs. accurate. We found that rate distributions were, indeed, very close to Normal, shifting to lower rates with increasing difficulty and accuracy, and for some blocks subjects they appeared to become left-truncated, but still close to Normal. Using autoregressive techniques, we found temporal sequential dependencies for lags of at least 3. We identified a transient and steady-state component in each block. Because rates were Normal, we were able to estimate autoregressive weights using the Box-Jenkins technique, and convert to a moving average model using z-transforms to show explicit dependence on stimulus input. We also found a spatial sequential dependence for the previous 3 lags depending on whether the laterality of previous trials was repeated or alternated. This was partially dissociated from temporal dependency as it only occurred in the easy tasks. We conclude that 2-alternative choice manual RT distributions are close to reciprocal Normal and not the inverse Gaussian. This is not consistent with stochastic rise to threshold models, and we propose a simple optimality model in which reward is maximized to yield to an optimal rate, and hence an optimal time to respond. We discuss how it might be

Impact of solids residence time on biological nutrient removal performance of membrane bioreactor.

Science.gov (United States)

Ersu, Cagatayhan Bekir; Ong, Say Kee; Arslankaya, Ertan; Lee, Yong-Woo

2010-05-01

Impact of long solids residence times (SRTs) on nutrient removal was investigated using a submerged plate-frame membrane bioreactor with anaerobic and anoxic tanks. The system was operated at 10, 25, 50 and 75 days SRTs with hydraulic retention times (HRTs) of 2 h each for the anaerobic and anoxic tanks and 8 h for the oxic tank. Recirculation of oxic tank mixed liquor into the anaerobic tank and permeate into the anoxic tank were fixed at 100% each of the influent flow. For all SRTs, percent removals of soluble chemical oxygen demand were more than 93% and nitrification was more than 98.5% but total nitrogen percent removal seemed to peak at 81% at 50 days SRT while total phosphorus (TP) percent removal showed a deterioration from approximately 80% at 50 days SRT to 60% at 75 days SRT. Before calibrating the Biowin((R)) model to the experimental data, a sensitivity analysis of the model was conducted which indicated that heterotrophic anoxic yield, anaerobic hydrolysis factors of heterotrophs, heterotrophic hydrolysis, oxic endogenous decay rate for heterotrophs and oxic endogenous decay rate of PAOs had the most impact on predicted effluent TP concentration. The final values of kinetic parameters obtained in the calibration seemed to imply that nitrogen and phosphorus removal increased with SRT due to an increase in anoxic and anaerobic hydrolysis factors up to 50 days SRT but beyond that removal of phosphorus deteriorated due to high oxic endogenous decay rates. This indirectly imply that the decrease in phosphorus removal at 75 days SRT may be due to an increase in lysis of microbial cells at high SRTs along with the low food/microorganisms ratio as a result of high suspended solids in the oxic tank. Several polynomial correlations relating the various calibrated kinetic parameters with SRTs were derived. The Biowin((R)) model and the kinetic parameters predicted by the polynomial correlations were verified and found to predict well the effluent water quality

Calculation of the permeability in porous media using the lattice Boltzmann method

International Nuclear Information System (INIS)

Eshghinejadfard, Amir; Daróczy, László; Janiga, Gábor; Thévenin, Dominique

2016-01-01

Highlights: • Lattice Boltzmann simulation of fluid flow in porous media delivers a high accuracy. • Domain size, relaxation time and force scheme affect the calculated permeability. • Multiple relaxation time model shows very low viscosity dependence as compared to single relaxation time. • The choice of relaxation time and force scheme is a trade-off between the required accuracy and computational cost. - Abstract: In this paper, the lattice Boltzmann method (LBM) is used to simulate three-dimensional laminar flows in porous media and to calculate the associated permeability. An in-house, parallelized code using the message passing interface technique is employed for the study. Three different flow configurations are studied: first, by manually specifying solid cells in a face-centered cube (FCC); then, doing the same in a body-centered cube (BCC); and finally by reading the solid cells for a real 3D geometry from a set of experimental 2D computed tomography images. In all simulations, the Reynolds number is kept well below 1. It was found that the current LBM simulations yield good estimates for the permeability value. The impact of the employed force scheme and single- or multiple-relaxation time (SRT, MRT) was also studied. Although each force scheme (Guo-SRT, Guo-MRT and Shan-Chen-SRT) may show better results in some regions, the strong dependency of SRT models on relaxation time suggests that the proper choice of the force scheme, relaxation time and domain resolution is a compromise between the required accuracy and computational cost. First, higher resolutions lead as expected to increasingly accurate results but requires more computational cost and time. Second, the MRT model shows a lower viscosity dependence in comparison with SRT models but is somewhat slower. Also, the results are more sensitive to the relaxation time value for coarser domains. Furthermore, lower relaxation times necessitate a higher number of iterations to reach the steady

Future Time Perspective Impacts Gain-Related but Not Loss-Related Intertemporal Choice.

Science.gov (United States)

Li, Tian; Tan, Yuxin; Gong, Xianmin; Yin, Shufei; Qiu, Fangshu; Hu, Xue

2018-01-01

Future time perspective (FTP) modulates individuals' temporal orientation in selecting their motivations and goals, which widely influences their cognitions and behaviors. However, it remains unclear how FTP exactly affects intertemporal choice. To clarify the effect of FTP on intertemporal choice, 90 college students ( M age = 21.70, SD = 1.23) were randomly assigned to the limited FTP condition (16 males, 29 females) and the open-ended FTP condition (17 males, 28 females). In the limited FTP condition, participants were instructed to imagine their states of being 70 years old, whereas in the open-ended FTP condition, they were instructed to describe their current states. All participants then completed a series of intertemporal choice tasks, in which they chose from gain- and loss-related choices occurring at various time points. Results showed that the participants who received the future-imagining manipulation had more limited FTP compared with those who did not receive the manipulation, which confirmed the validity of the FTP manipulation. A 2 (FTP: limited vs. open-ended) × 2 (type of choice: gain vs. loss) repeated measures ANOVA on discount rate revealed a significant interaction between these two factors. The participants in the limited FTP condition had higher discount rates on gain-related choices but showed no difference on loss-related choices compared with the participants under the open-ended FTP condition. The results suggest that limited FTP could lower individuals' future orientation (i.e., willingness to delay an outcome) on gain-related, but not on loss-related, intertemporal decision-making.

Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

Science.gov (United States)

Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

2016-11-01

The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

How libraries make tough choices in difficult times purposeful abandonment

CERN Document Server

Stern, David

2013-01-01

Contemporary library managers face the need to make difficult choices regarding resource allocation in the modern business environment. How Libraries Make Tough Choices in Difficult Times is a practical guide for library managers, offering techniques to analyze existing and potential services, implement best practices for maximizing existing resources, and utilize pressing financial scenarios in order to justify making difficult reallocation decisions. The book begins by asking the fundamental questions of why, what, and how, moving on to look at how to manage expectations and report to both a

Impact of sludge retention time on the fine composition of the microbial community and extracellular polymeric substances in a membrane bioreactor.

Science.gov (United States)

Silva, Ana F; Antunes, Sílvia; Saunders, Aaron; Freitas, Filomena; Vieira, Anabela; Galinha, Claudia F; Nielsen, Per H; Barreto Crespo, Maria Teresa; Carvalho, Gilda

2016-10-01

Membrane bioreactors (MBRs) are an advanced technology for wastewater treatment whose wide application has been hindered by rapid fouling of the membranes. MBRs can be operated with long sludge retention time (SRT), a crucial parameter impacting microbial selection in the reactor. This also affects filtration performance, since a major fouling agent are the extracellular polymeric substances (EPS). In this study, the impact of the SRT on the ecophysiology of the MBRs and, consequently, on membrane fouling was evaluated. A MBR was operated under a SRT of 60 days followed by a SRT of 20 days. A comprehensive analysis of the microbial community structure and EPS proteins and polysaccharide profiles of the mixed liquor and cake layer was carried out throughout both operation periods. The results of this study showed that the imposition of a shorter SRT led to a shift in the dominant bacterial populations. The mixed liquor and cake layer communities were very different, with Actinomycetales order standing out in the cake layer at SRT of 20 days. Overall, higher EPS concentrations (particularly proteins) were found at this SRT. Furthermore, EPS profiles were clearly affected by the SRT: it was possible to correlate a group of soluble EPS proteins with the SRT of 60 days, and a lower sludge age led to a lower diversity of polysaccharide sugar monomers, with an increase of glucose and galactose in the cake layer. This study improves our knowledge regarding the molecular reasons for fouling, which may contribute to improve MBR design and operation.

Discretionary Time of Chinese College Students: Activities and Impact of SARS-Induced Constraints on Choices

Science.gov (United States)

Yang, He; Hutchinson, Susan; Zinn, Harry; Watson, Alan

2011-01-01

How people make choices about activity engagement during discretionary time is a topic of increasing interest to those studying quality of life issues. Assuming choices are made to maximize individual welfare, several factors are believed to influence these choices. Constraints theory from the leisure research literature suggests these choices are…

Discretionary time of Chinese college students: Activities and impact of SARS-induced constraints on choices

Science.gov (United States)

He Yang; Susan Hutchinson; Harry Zinn; Alan Watson

2011-01-01

How people make choices about activity engagement during discretionary time is a topic of increasing interest to those studying quality of life issues. Assuming choices are made to maximize individual welfare, several factors are believed to influence these choices. Constraints theory from the leisure research literature suggests these choices are heavily influenced by...

Reproducibility of frequency-dependent low frequency fluctuations in reaction time over time and across tasks.

Science.gov (United States)

Liu, Zan-Zan; Qu, Hui-Jie; Tian, Zhuo-Ling; Han, Meng-Jian; Fan, Yi; Ge, Lie-Zhong; Zang, Yu-Feng; Zhang, Hang

2017-01-01

Increased levels of reaction time variability (RTV) are characteristics of sustained attention deficits. The clinical significance of RTV has been widely recognized. However, the reliability of RTV measurements has not been widely studied. The present study aimed to assess the test-retest reliability of RTV conventional measurements, e.g., the standard deviation (SD), the coefficient of variation (CV), and a new measurement called the amplitude of low frequency fluctuation (ALFF) of RT. In addition, we aimed to assess differences and similarities of these measurements between different tasks. Thirty-seven healthy college students participated in 2 tasks, i.e., an Eriksen flanker task (EFT) and a simple reaction task (SRT), twice over a mean interval of 56 days. Conventional measurements of RTV including RT-SD and RT-CV were assessed first. Then the RT time series were converted into frequency domains, and RT-ALFF was further calculated for the whole frequency band (0.0023-0.167 Hz) and for a few sub-frequency bands including Slow-6 (frequency bands (Slow-3), but SRT RT-ALFF values showed slightly higher ICC values than EFT values in lower frequency bands (Slow-5 and Slow-4). 2) RT-ALFF magnitudes in each sub-frequency band were greater for the SRT than those for the EFT. 3) The RT-ALFF in the Slow-4 of the EFT was found to be correlated with the RT-ALFF in the Slow-5 of the SRT for both two visits, but no consistently significant correlation was found between the same frequency bands. These findings reveal good test-retest reliability for conventional measurements and for the RT-ALFF of RTV. The RT-ALFF presented frequency-dependent similarities across tasks. All of our results reveal the presence of different frequency structures between the two tasks, and thus the frequency-dependent characteristics of different tasks deserve more attention in future studies.

The relationship between the intelligibility of time-compressed speech and speech in noise in young and elderly listeners

Science.gov (United States)

Versfeld, Niek J.; Dreschler, Wouter A.

2002-01-01

A conventional measure to determine the ability to understand speech in noisy backgrounds is the so-called speech reception threshold (SRT) for sentences. It yields the signal-to-noise ratio (in dB) for which half of the sentences are correctly perceived. The SRT defines to what degree speech must be audible to a listener in order to become just intelligible. There are indications that elderly listeners have greater difficulty in understanding speech in adverse listening conditions than young listeners. This may be partly due to the differences in hearing sensitivity (presbycusis), hence audibility, but other factors, such as temporal acuity, may also play a significant role. A potential measure for the temporal acuity may be the threshold to which speech can be accelerated, or compressed in time. A new test is introduced where the speech rate is varied adaptively. In analogy to the SRT, the time-compression threshold (or TCT) then is defined as the speech rate (expressed in syllables per second) for which half of the sentences are correctly perceived. In experiment I, the TCT test is introduced and normative data are provided. In experiment II, four groups of subjects (young and elderly normal-hearing and hearing-impaired subjects) participated, and the SRT's in stationary and fluctuating speech-shaped noise were determined, as well as the TCT. The results show that the SRT in fluctuating noise and the TCT are highly correlated. All tests indicate that, even after correction for the hearing loss, elderly normal-hearing subjects perform worse than young normal-hearing subjects. The results indicate that the use of the TCT test or the SRT test in fluctuating noise is preferred over the SRT test in stationary noise.

Operation of Small Radio Telescope (SRT) recorded 21 cm spectral line of Hydrogen at VATLY Laboratory

International Nuclear Information System (INIS)

Pham Ngoc Dong; Pham Tuan Anh; Pham Ngoc Diep; Pham Thi Tuyet Nhung; Nguyen Van Hiep

2013-01-01

A small radio telescope (SRT) has been installed on the roof of the Hanoi astrophysics laboratory VATLY. It is equipped with a 2.6 m diameter mobile parabolic dish remotely controlled in elevation and azimuth and with super-heterodyne detection around the 21 cm hydrogen line. They demonstrate the high quality of the telescope performance and are used to evaluate lobe size, signal to noise ratios, anthropogenic interferences and measurement accuracies. Particular attention is given to the measurement of the pointing accuracy. First results of observations of the Sun and of the centre of the Milky Way are presented. (author)

Predictor of response to salvage radiotherapy in patients with PSA recurrence after radical prostatectomy. The usefulness of PSA doubling time

International Nuclear Information System (INIS)

Numata, Kousaku; Azuma, Koji; Hashine, Katsuyoshi; Sumiyoshi, Yoshiteru

2005-01-01

We assessed predictors of response to salvage radiotherapy (sRT) in patients with prostate-specific antigen (PSA) recurrence after radical prostatectomy. A total of 21 patients receiving sRT for PSA recurrence without systemic progression after radical prostatectomy had medical records available for retrospective review. We defined sRT as external beam radiotherapy for patients with a continuous increase in PSA level≥0.2 ng/ml after radical prostatectomy. Response was defined as achievement of a PSA nadir of ≤0.1 ng/ml. Various pre-treatment parameters were evaluated retrospectively. The median follow-up period after sRT was 38 months. Of the 21 patients, 15 were good responders (71%). The only predictive factor was PSA doubling time (PSADT). Age and PSA level at diagnosis, Gleason score and surgical margin status were not significant predictors of response. The median PSADT in responders was 6.2 months versus 1.9 months in non-responders (P=0.019). The patients with a PSADT of ≥5 months were all responders. PSADT appears to be a good predictor of response to sRT. sRT was especially effective when PSADT was ≥5 months. (author)

Secular slowing auditory simple reaction time in Sweden (1959-1985

Directory of Open Access Journals (Sweden)

Guy Madison

2016-08-01

Full Text Available There are indications that simple reaction time might have slowed in Western countries, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT of 7,081 individuals (2,997 males and 4,084 females born in Sweden 1959-1985 (subjects were aged between 27 and 54 years at time of measurement. Depending on cut-offs and adjustment for ageing related slowing on SRT, the data suggest that SRT has increased between 3 and 16 ms in the 27 birth years covered in the present sample. The slowing is unlikely to be explained by attrition, as evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may result from several synergistic factors, such as possible recent micro-evolutionary trends favouring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.

Choice certainty in Discrete Choice Experiments

DEFF Research Database (Denmark)

Uggeldahl, Kennet Christian; Jacobsen, Catrine; Lundhede, Thomas

2016-01-01

In this study, we conduct a Discrete Choice Experiment (DCE) using eye tracking technology to investigate if eye movements during the completion of choice sets reveal information about respondents’ choice certainty. We hypothesise that the number of times that respondents shift their visual...

SRTC criticality safety technical review: Phase 1 criticality analysis for the 9972-9975 family of shipping casks: (SRT-CMA-940003)

International Nuclear Information System (INIS)

Rathbun, R.

1994-01-01

Review of SRT-CMA-940003, ''Phase I Criticality Analysis For The 9972-9975 Family Of Shipping Casks (U). (SRT-CMA-940003).'' January 22, 1994, has been performed by the SRTC Applied Physics Group. The NCSE is a criticality assessment of the 9972-9975 family of shipping casks. This work is a follow-on of a previous criticality safety evaluation, with the differences between this and the previous evaluation are that now wall tolerances are modeled and more sophisticated analytical methods are applied. The NCSE under review concludes that, with one exception, the previously specified plutonium and uranium mass limits for 9972-9975 family of shipping casks do ensure that WSRC Nuclear Criticality Safety Manual requirements (ref. 1) are satisfied. The one exception is that the plutonium mass limit for the 9974 cask had to be reduced from 4.4 to 4.3 kg. In contrast, the 7.5 kg uranium mass limit for the 9974 cask was raised to 14.5 kg, making the uranium mass identical for all casks in this family. This technical review consisted of an independent check of the methods and models employed, application of ANSI/ANS 8.1 and 8.15, and verification of WSRC Nuclear Criticality Safety Manual procedures

Otimização de propriedades mecânicas de misturas ternárias de polipropileno (PP/borracha de etileno-propileno-dieno (EPDM/pó de pneus (SRT sob tração e impacto usando a metodologia da superfície de resposta (MSR Optimization of mechanical properties of polypropylene (PP/ethylene-propylene-diene monomer rubber (EPDM/scrap rubber tire (SRT ternary mixtures under tensile and impact using the response surface methodology (RSM

Directory of Open Access Journals (Sweden)

Helson M. da Costa

2012-01-01

Full Text Available A metodologia da superfície de resposta (MSR é uma coleção de técnicas estatísticas e matemáticas para desenvolver, melhorar e otimizar processos. Neste estudo, a técnica MSR foi aplicada na investigação do comportamento mecânico de diferentes misturas ternárias de PP/EPDM/SRT. Após a mistura apropriada em uma extrusora de dupla rosca co-rotante e a moldagem por injeção, as propriedades mecânicas (resistência à tração e a resistência ao impacto foram determinadas e usadas como variáveis de resposta. A microscopia eletrônica de varredura (MEV foi usada para investigar a morfologia das diferentes misturas e interpretar os resultados. Com ferramentas estatísticas específicas, um número mínimo de experimentos permitiu o desenvolvimento de um modelo de superfície de resposta e a otimização das concentrações dos componentes de acordo com o desempenho mecânico. Valores elevados de resistência ao impacto são alcançados (>80 J.m-1 quando, de acordo com as condições experimentais estudadas, a mistura física de PP/EPDM/SRT mantém as proporções de EPDM e SRT em torno de 25%.The response surface methodology (RSM is a collection of statistical and mathematical techniques for developing, improving and optimizing processes. In this study, RSM technique was applied to the investigation of the mechanical behavior of different PP/EPDM/SRT ternary mixtures. After appropriate processing in a co-rotating twin extruder and injection molding, the mechanical properties, such as tensile strength and impact strength, were determined and used as response variables. Scanning electron microscopy (SEM was used for investigating the morphology of the different blends and to interpret the results. With specific statistical tools, a minimum number of experiments allowed the response surface model to be developed and the concentrations of the components to be optimized according to the mechanical performance. High values of impact

Leveraging delay discounting for health: Can time delays influence food choice?

Science.gov (United States)

Appelhans, Bradley M; French, Simone A; Olinger, Tamara; Bogucki, Michael; Janssen, Imke; Avery-Mamer, Elizabeth F; Powell, Lisa M

2018-03-15

Delay discounting, the tendency to choose smaller immediate rewards over larger delayed rewards, is theorized to promote consumption of immediately rewarding but unhealthy foods at the expense of long-term weight maintenance and nutritional health. An untested implication of delay discounting models of decision-making is that selectively delaying access to less healthy foods may promote selection of healthier (immediately available) alternatives, even if they may be less desirable. The current study tested this hypothesis by measuring healthy versus regular vending machine snack purchasing before and during the implementation of a 25-s time delay on the delivery of regular snacks. Purchasing was also examined under a $0.25 discount on healthy snacks, a $0.25 tax on regular snacks, and the combination of both pricing interventions with the 25-s time delay. Across 32,019 vending sales from three separate vending locations, the 25-s time delay increased healthy snack purchasing from 40.1% to 42.5%, which was comparable to the impact of a $0.25 discount (43.0%). Combining the delay and the discount had a roughly additive effect (46.0%). However, the strongest effects were seen under the $0.25 tax on regular snacks (53.7%) and the combination of the delay and the tax (50.2%). Intervention effects varied substantially between vending locations. Importantly, time delays did not harm overall vending sales or revenue, which is relevant to the real-world feasibility of this intervention. More investigation is needed to better understand how the impact of time delays on food choice varies across populations, evaluate the effects of time delays on beverage vending choices, and extend this approach to food choices in contexts other than vending machines. ClinicalTrials.gov, NCT02359916. Copyright © 2018 Elsevier Ltd. All rights reserved.

The role of intention as mediator between latent effects and behavior: application of a hybrid choice model to study departure time choices

DEFF Research Database (Denmark)

Thorhauge, Mikkel; Cherchi, Elisabetta; Walker, Joan L.

2017-01-01

of them consider the effect of intention and its role as mediator between those psychological effects and the choice, as implied in the Theory of Planned Behavior. In this paper we contribute to the literature in this field by specifically studying the direct effect of the intention on the actual behavior......, while attitude, social norms, and perceived behavioral control affect the intention to behave in a given way. We apply a hybrid choice model to study the departure time choice. For this, we use data from Danish commuters in the morning rush hours in the Greater Copenhagen area. We find a significant...

Influence of sludge retention time on tolerance of copper toxicity for polyphosphate accumulating organisms linked to polyhydroxyalkanoates metabolism and phosphate removal.

Science.gov (United States)

Tsai, Yung-Pin; Chen, Hsiu-Ting

2011-12-01

This study explored the influence of sludge retention time (SRT) on tolerance of copper invasion for polyphosphate accumulating organisms (PAOs) in an enhanced biological phosphorus removal (EBPR). The experimental data showed the anaerobic polyhydroxyalkanoates (PHA) storage for the sludge at 10d SRT was less influenced by copper invasion than those at 5d and 15d SRTs. The reaction of PAOs aerobically taking up phosphate for the sludge at 5d or 15d SRT almost ceased at 2 mg Cu L(-1), whereas PAOs in the sludge at 10d SRT retained half of the ability to take up phosphate. Both the PHAs degradation and synthesis rates decreased with increasing copper concentration, regardless of the SRTs. However, the copper inhibition of the former was greater than that of the later. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Determinants of the choice of part time employment and nurses' satisfaction: a multicentre descriptive study].

Science.gov (United States)

Ferrazzo, Martino; Filippi, Mauro; Meneghetti, Giulia; Palese, Alvisa

2012-01-01

To describe the main determinants for the choice of part time employment in Italian nurses and its' impact on work satisfaction. The main factors were identified with a focus-group. A questionnaire with 26 items for the choice of part time and 24 for work satisfaction was then devised and administered to part time nurses (503) of 5 North Italian hospitals. Two-hundred fifty-five nurses/471 answered the questionnaire. The choice of part time was voluntary for the large majority of nurses (251, 98.4%) except for 4 (1.6%) that asked for it for health problems (personal or of the spouse). Part time nurses are more satisfied for the relationships with colleagues (average 3; SD 0.6), the opportunity to deal with responsibilities (2.9; SD 0.6) and to have free time (2.9; SD 0.6). CONCLUSIONS; Part time is a need for mothers. Part time nurses complain for lack of access to information on patients and lack of involvement in ward projects and planned changes, possibly to be considered signals of isolation.

Sleep restriction therapy for insomnia is associated with reduced objective total sleep time, increased daytime somnolence, and objectively impaired vigilance: implications for the clinical management of insomnia disorder.

Science.gov (United States)

Kyle, Simon D; Miller, Christopher B; Rogers, Zoe; Siriwardena, A Niroshan; Macmahon, Kenneth M; Espie, Colin A

2014-02-01

To investigate whether sleep restriction therapy (SRT) is associated with reduced objective total sleep time (TST), increased daytime somnolence, and impaired vigilance. Within-subject, noncontrolled treatment investigation. Sleep research laboratory. Sixteen patients [10 female, mean age = 47.1 (10.8) y] with well-defined psychophysiological insomnia (PI), reporting TST ≤ 6 h. Patients were treated with single-component SRT over a 4-w protocol, sleeping in the laboratory for 2 nights prior to treatment initiation and for 3 nights (SRT night 1, 8, 22) during the acute interventional phase. The psychomotor vigilance task (PVT) was completed at seven defined time points [day 0 (baseline), day 1,7,8,21,22 (acute treatment) and day 84 (3 mo)]. The Epworth Sleepiness Scale (ESS) was completed at baseline, w 1-4, and 3 mo. Subjective sleep outcomes and global insomnia severity significantly improved before and after SRT. There was, however, a robust decrease in PSG-defined TST during acute implementation of SRT, by an average of 91 min on night 1, 78 min on night 8, and 69 min on night 22, relative to baseline (P insomnia.

Calibration of a joint time assignment and mode choice model system

OpenAIRE

Greeven, Paulina; Jara-Diaz, Sergio R.; Munizaga, Marcela A.; Axhausen, Kay W.

2005-01-01

In this paper we report the results of applying a new microeconomic framework to model time assignment to activities, goods consumption and mode choice jointly (Jara-Díaz and Guevara, 2003; Jara-Díaz and Guerra, 2003) that identifies the links between these decisions and permits the calculation of all the components of the subjective value of time defined in the literature: the value of time as a resource, value of assigning time to a specific activity and the value of saving time in a specif...

Testing the effect of time pressure on asymmetric dominance and compromise decoys in choice

Directory of Open Access Journals (Sweden)

Jonathan Pettibone

2012-07-01

Full Text Available Dynamic, connectionist models of decision making, such as decision field theory (Roe, Busemeyer, and Townsend, 2001, propose that the effect of context on choice arises from a series of pairwise comparisons between attributes of alternatives across time. As such, they predict that limiting the amount of time to make a decision should decrease rather than increase the size of contextual effects. This prediction was tested across four levels of time pressure on both the asymmetric dominance (Huber, Payne, and Puto, 1982 and compromise (Simonson, 1989 decoy effects in choice. Overall, results supported this prediction, with both types of decoy effects found to be larger as time pressure decreased.

Procedural learning is impaired in dyslexia: Evidence from a meta-analysis of serial reaction time studies☆

Science.gov (United States)

Lum, Jarrad A.G.; Ullman, Michael T.; Conti-Ramsden, Gina

2013-01-01

A number of studies have investigated procedural learning in dyslexia using serial reaction time (SRT) tasks. Overall, the results have been mixed, with evidence of both impaired and intact learning reported. We undertook a systematic search of studies that examined procedural learning using SRT tasks, and synthesized the data using meta-analysis. A total of 14 studies were identified, representing data from 314 individuals with dyslexia and 317 typically developing control participants. The results indicate that, on average, individuals with dyslexia have worse procedural learning abilities than controls, as indexed by sequence learning on the SRT task. The average weighted standardized mean difference (the effect size) was found to be 0.449 (CI95: .204, .693), and was significant (p dyslexia. PMID:23920029

SRT project: tele-robotics maintenance of nuclear power plants

International Nuclear Information System (INIS)

Gomez-Santamaria, J.; Calleja, J.M.; Carmena, P.; Avello, A.; Rubio, Y.A.

2001-01-01

The main aim of the SRT project was to develop a family of robots to help in the operation of nuclear power plants. Four robotic systems were developed and this paper focuses on three of them: ANAES -a steam leak detector through noise analysis-, MALIBA -a master-slave tele-operation system with force feedback- and ROBICEN -a compact pneumatic wall climbing robot-. ANAES (the Spanish acronym of spectrum analysis) consists of a set of sensor heads attached to a computer. Each head has two microphones and a video camera installed on it, and a DC motor that rotates the head. The heads are shielded with lead and boron steel, especially near the video camera. The noise generated by the plant is recorded every day at the same time and the software compares the recorded noise with the mean values of past records. The system can discern whether the noise has remarkably changed and, through phase analysis of the sound recorded by both microphones, identifies the direction of arrival (DOA) of the new noise, probably a steam leak. Using several heads, the new noise source can be identified. The video camera can be used to ease the location of the steam leaks. The stationariness of the measured noise has been tested in C.N. Cofrentes -a Spanish BWR-6 reactor-. A finished system with six heads has recently been installed in the MSR (moisture separator reheater) of the same plant. MALIBA is a master-slave tele-operated system with force feedback. It consists of two robots: a Stewart platform used as master robot and an open chain robot used as slave. The slave robot follows faithfully the movements of the master, and the master robot can reflect a force proportional to the force exerted by the slave on the environment. Three tools have been developed for the slave robot: a robot hand that includes a small video camera, a pneumatic drill and a rectifier. The results obtained have shown its effectiveness for the designed operations. ROBICEN is a lightweight pneumatic robot

SRT project: tele-robotics maintenance of nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Gomez-Santamaria, J. [Iberdrola SA, Madrid (Spain); Calleja, J.M.; Carmena, P. [Endesa, Madrid (Spain); Avello, A.; Rubio, Y.A. [CEIT-Centro de Estudias e Investigaciones Tecnicas de Guipuzcoa, San Sebastian (Spain)

2001-07-01

The main aim of the SRT project was to develop a family of robots to help in the operation of nuclear power plants. Four robotic systems were developed and this paper focuses on three of them: ANAES -a steam leak detector through noise analysis-, MALIBA -a master-slave tele-operation system with force feedback- and ROBICEN -a compact pneumatic wall climbing robot-. ANAES (the Spanish acronym of spectrum analysis) consists of a set of sensor heads attached to a computer. Each head has two microphones and a video camera installed on it, and a DC motor that rotates the head. The heads are shielded with lead and boron steel, especially near the video camera. The noise generated by the plant is recorded every day at the same time and the software compares the recorded noise with the mean values of past records. The system can discern whether the noise has remarkably changed and, through phase analysis of the sound recorded by both microphones, identifies the direction of arrival (DOA) of the new noise, probably a steam leak. Using several heads, the new noise source can be identified. The video camera can be used to ease the location of the steam leaks. The stationariness of the measured noise has been tested in C.N. Cofrentes -a Spanish BWR-6 reactor-. A finished system with six heads has recently been installed in the MSR (moisture separator reheater) of the same plant. MALIBA is a master-slave tele-operated system with force feedback. It consists of two robots: a Stewart platform used as master robot and an open chain robot used as slave. The slave robot follows faithfully the movements of the master, and the master robot can reflect a force proportional to the force exerted by the slave on the environment. Three tools have been developed for the slave robot: a robot hand that includes a small video camera, a pneumatic drill and a rectifier. The results obtained have shown its effectiveness for the designed operations. ROBICEN is a lightweight pneumatic robot

Does Ethnicity Matter For Food Choices? An Empirical Analysis of Asian Immigrant Time Use

OpenAIRE

Yang, Tongyang; Berning, Joshua; Colson, Greg; Smith, Travis A.

2015-01-01

As immigrants settle and extend their stay in the U.S., they may be exposed to a food culture and lifestyle that impacts their food choice decisions and health outcomes. This paper focuses on the behavioral changes and acculturation level of different generations of Asian immigrants on food choice decisions employing the 2013 American Time Use Survey. Heckman two-step regression results indicate that the 1st generation immigrants participate or spend more time on eating and drinking, food pre...

Widely applicable MATLAB routines for automated analysis of saccadic reaction times.

Science.gov (United States)

Leppänen, Jukka M; Forssman, Linda; Kaatiala, Jussi; Yrttiaho, Santeri; Wass, Sam

2015-06-01

Saccadic reaction time (SRT) is a widely used dependent variable in eye-tracking studies of human cognition and its disorders. SRTs are also frequently measured in studies with special populations, such as infants and young children, who are limited in their ability to follow verbal instructions and remain in a stable position over time. In this article, we describe a library of MATLAB routines (Mathworks, Natick, MA) that are designed to (1) enable completely automated implementation of SRT analysis for multiple data sets and (2) cope with the unique challenges of analyzing SRTs from eye-tracking data collected from poorly cooperating participants. The library includes preprocessing and SRT analysis routines. The preprocessing routines (i.e., moving median filter and interpolation) are designed to remove technical artifacts and missing samples from raw eye-tracking data. The SRTs are detected by a simple algorithm that identifies the last point of gaze in the area of interest, but, critically, the extracted SRTs are further subjected to a number of postanalysis verification checks to exclude values contaminated by artifacts. Example analyses of data from 5- to 11-month-old infants demonstrated that SRTs extracted with the proposed routines were in high agreement with SRTs obtained manually from video records, robust against potential sources of artifact, and exhibited moderate to high test-retest stability. We propose that the present library has wide utility in standardizing and automating SRT-based cognitive testing in various populations. The MATLAB routines are open source and can be downloaded from http://www.uta.fi/med/icl/methods.html .

The impact of total sleep deprivation upon cognitive functioning in firefighters

Directory of Open Access Journals (Sweden)

Kujawski S

2018-05-01

Full Text Available Sławomir Kujawski,1 Joanna Słomko,1 Małgorzata Tafil-Klawe,2 Monika Zawadka-Kunikowska,1 Justyna Szrajda,1 Julia L Newton,3 Paweł Zalewski,1 Jacek J Klawe1 1Department of Hygiene, Epidemiology and Ergonomics, Nicolaus Copernicus University, Toruń, Poland; 2Department of Human Physiology, Nicolaus Copernicus University, Toruń, Poland; 3Institute for Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, UK Introduction: Firefighters as a profession are required to maintain high levels of attention for prolonged periods. However, total sleep deprivation (TSD could influence negatively upon performance, particularly when the task is prolonged and repetitive. Purpose: The aim of this study is to examine the influence of TSD on cognitive functioning in a group of firefighters. Subjects and methods: Sixty volunteers who were active male fire brigade officers were examined with a computerized battery test that consisted of simple reaction time (SRT (repeated three times, choice reaction time, visual attention test, and delayed matching to sample. Six series of measurements were undertaken over a period of TSD. Results: Performance in the second attempt in SRT test was significantly worse in terms of increased number of errors and, consequently, decreased number of correct responses during TSD. In contrast, the choice reaction time number of correct responses as well as the visual attention test reaction time for all and correct responses significantly improved compared to initial time points. Conclusion: The study has confirmed that subjects committed significantly more errors and, consequently, noted a smaller number of correct responses in the second attempt of SRT test. However, the remaining results showed reversed direction of TSD influence. TSD potentially leads to worse performance in a relatively easy task in a group of firefighters. Errors during repetitive tasks in firefighting

The role of stereotactic radiation therapy and whole-brain radiotherapy in the treatment of multiple brain metastases

International Nuclear Information System (INIS)

Chen Xiujun; Xiao Jianping; Li Xiangpan; Jiang Xuesong; Zhang Ye; Xu Yingjie; Dai Jianrong; Li Yexiong

2012-01-01

Objective: To summarize the results of stereotactic radiation therapy (SRT) with or without whole-brain radiotherapy (WBRT) in the treatment of multiple brain metastasis. Methods: From May 1995 to April 2010, totally 98 newly diagnosed multiple (2 - 13 lesions) brain metastases patients were treated in our centre. Forty-four patients were treated with SRT alone and 54 with SRT + WBRT. Dose fractionation schemes were 15 -26 Gy in 1 fraction or 24.0 -52.5 Gy in 2 - 15 fractions with 3.5 - 12.0 Gy per fraction, depending on the tumor volume, location, and history of prior irradiation. Kaplan-Meier and Cox proportional hazards regression analyses were used for survival analysis. The median age of the whole group was 55 years. The survival time was calculated from the date of radiation treatment to the day of death by any cause. Results: The median follow-up time for the whole group was 12 months, and the follow-up rate was 100%. The median overall survival time was 13.5 months for the whole group, there was no difference between SRT alone group and SRT + WBRT group (13.0 months vs. 13.5 months, χ 2 =0.31, P =0.578). The Karnofsky Performance Score (KPS) at the time of treatment (χ 2 =6.25, P =0.012), the interval between the diagnosis of the primary tumor and brain metastases (χ 2 =7.34, P =0.025) and the status of extracranial metastases (χ 2 =4.20, P =0.040) were independent prognosis factors for survival in multivariate analyses. Conclusions: Stereotactic radiation therapy is an effective and alternative treatment choice for multiple brain metastases. (authors)

Flexible Scheduling by Deadline Inheritance in Soft Real Time Kernels

NARCIS (Netherlands)

Jansen, P.G.; Wygerink, Emiel

1996-01-01

Current Hard Real Time (HRT) kernels have their timely behaviour guaranteed on the cost of a rather restrictive use of the available resources. This makes HRT scheduling techniques inadequate for use in Soft Real Time (SRT) environment where we can make a considerable profit by a better and more

Constrained choices? Linking employees' and spouses' work time to health behaviors.

Science.gov (United States)

Fan, Wen; Lam, Jack; Moen, Phyllis; Kelly, Erin; King, Rosalind; McHale, Susan

2015-02-01

There are extensive literatures on work conditions and health and on family contexts and health, but less research asking how a spouse or partners' work conditions may affect health behaviors. Drawing on the constrained choices framework, we theorized health behaviors as a product of one's own time and spouses' work time as well as gender expectations. We examined fast food consumption and exercise behaviors using survey data from 429 employees in an Information Technology (IT) division of a U.S. Fortune 500 firm and from their spouses. We found fast food consumption is affected by men's work hours-both male employees' own work hours and the hours worked by husbands of women respondents-in a nonlinear way. The groups most likely to eat fast food are men working 50 h/week and women whose husbands work 45-50 h/week. Second, exercise is better explained if work time is conceptualized at the couple, rather than individual, level. In particular, neo-traditional arrangements (where husbands work longer than their wives) constrain women's ability to engage in exercise but increase odds of men exercising. Women in couples where both partners are working long hours have the highest odds of exercise. In addition, women working long hours with high schedule control are more apt to exercise and men working long hours whose wives have high schedule flexibility are as well. Our findings suggest different health behaviors may have distinct antecedents but gendered work-family expectations shape time allocations in ways that promote men's and constrain women's health behaviors. They also suggest the need to expand the constrained choices framework to recognize that long hours may encourage exercise if both partners are looking to sustain long work hours and that work resources, specifically schedule control, of one partner may expand the choices of the other. Copyright © 2014 Elsevier Ltd. All rights reserved.

The modulation of simple reaction time by the spatial probability of a visual stimulus

Directory of Open Access Journals (Sweden)

Carreiro L.R.R.

2003-01-01

Full Text Available Simple reaction time (SRT in response to visual stimuli can be influenced by many stimulus features. The speed and accuracy with which observers respond to a visual stimulus may be improved by prior knowledge about the stimulus location, which can be obtained by manipulating the spatial probability of the stimulus. However, when higher spatial probability is achieved by holding constant the stimulus location throughout successive trials, the resulting improvement in performance can also be due to local sensory facilitation caused by the recurrent spatial location of a visual target (position priming. The main objective of the present investigation was to quantitatively evaluate the modulation of SRT by the spatial probability structure of a visual stimulus. In two experiments the volunteers had to respond as quickly as possible to the visual target presented on a computer screen by pressing an optic key with the index finger of the dominant hand. Experiment 1 (N = 14 investigated how SRT changed as a function of both the different levels of spatial probability and the subject's explicit knowledge about the precise probability structure of visual stimulation. We found a gradual decrease in SRT with increasing spatial probability of a visual target regardless of the observer's previous knowledge concerning the spatial probability of the stimulus. Error rates, below 2%, were independent of the spatial probability structure of the visual stimulus, suggesting the absence of a speed-accuracy trade-off. Experiment 2 (N = 12 examined whether changes in SRT in response to a spatially recurrent visual target might be accounted for simply by sensory and temporally local facilitation. The findings indicated that the decrease in SRT brought about by a spatially recurrent target was associated with its spatial predictability, and could not be accounted for solely in terms of sensory priming.

SU-E-T-304: Dosimetric Comparison of Cavernous Sinus Tumors: Heterogeneity Corrected Pencil Beam (PB-Hete) Vs. X-Ray Voxel Monte Carlo (XVMC) Algorithms for Stereotactic Radiotherapy (SRT)

Energy Technology Data Exchange (ETDEWEB)

Pokhrel, D; Sood, S; Badkul, R; Jiang, H; Saleh, H; Wang, F [University of Kansas Hospital, Kansas City, KS (United States)

2015-06-15

Purpose: To compare dose distributions calculated using PB-hete vs. XVMC algorithms for SRT treatments of cavernous sinus tumors. Methods: Using PB-hete SRT, five patients with cavernous sinus tumors received the prescription dose of 25 Gy in 5 fractions for planning target volume PTV(V100%)=95%. Gross tumor volume (GTV) and organs at risk (OARs) were delineated on T1/T2 MRI-CT-fused images. PTV (range 2.1–84.3cc, mean=21.7cc) was generated using a 5mm uniform-margin around GTV. PB-hete SRT plans included a combination of non-coplanar conformal arcs/static beams delivered by Novalis-TX consisting of HD-MLCs and a 6MV-SRS(1000 MU/min) beam. Plans were re-optimized using XVMC algorithm with identical beam geometry and MLC positions. Comparison of plan specific PTV(V99%), maximal, mean, isocenter doses, and total monitor units(MUs) were evaluated. Maximal dose to OARs such as brainstem, optic-pathway, spinal cord, and lenses as well as normal tissue volume receiving 12Gy(V12) were compared between two algorithms. All analysis was performed using two-tailed paired t-tests of an upper-bound p-value of <0.05. Results: Using either algorithm, no dosimetrically significant differences in PTV coverage (PTVV99%,maximal, mean, isocenter doses) and total number of MUs were observed (all p-values >0.05, mean ratios within 2%). However, maximal doses to optic-chiasm and nerves were significantly under-predicted using PB-hete (p=0.04). Maximal brainstem, spinal cord, lens dose and V12 were all comparable between two algorithms, with exception of one patient with the largest PTV who exhibited 11% higher V12 with XVMC. Conclusion: Unlike lung tumors, XVMC and PB-hete treatment plans provided similar PTV coverage for cavernous sinus tumors. Majority of OARs doses were comparable between two algorithms, except for small structures such as optic chiasm/nerves which could potentially receive higher doses when using XVMC algorithm. Special attention may need to be paid on a case

The Drift Diffusion Model can account for the accuracy and reaction time of value-based choices under high and low time pressure

Directory of Open Access Journals (Sweden)

Milica Milosavljevic

2010-10-01

Full Text Available An important open problem is how values are compared to make simple choices. A natural hypothesis is that the brain carries out the computations associated with the value comparisons in a manner consistent with the Drift Diffusion Model (DDM, since this model has been able to account for a large amount of data in other domains. We investigated the ability of four different versions of the DDM to explain the data in a real binary food choice task under conditions of high and low time pressure. We found that a seven-parameter version of the DDM can account for the choice and reaction time data with high-accuracy, in both the high and low time pressure conditions. The changes associated with the introduction of time pressure could be traced to changes in two key model parameters: the barrier height and the noise in the slope of the drift process.

Input price risk and optimal timing of energy investment: choice between fossil- and biofuels

Energy Technology Data Exchange (ETDEWEB)

Murto, Pauli; Nese, Gjermund

2002-05-01

We consider energy investment, when a choice has to be made between fossil fuel and biomass fired production technologies. A dynamic model is presented to illustrate the effect of the different degrees of input price uncertainty on the choice of technology and the timing of the investment. It is shown that when the choice of technology is irreversible, it may be optimal to postpone the investment even if it would otherwise be optimal to invest in one or both of the plant types. We provide a numerical example based on cost, estimates of two different power plant types. (author)

Input price risk and optimal timing of energy investment: choice between fossil- and biofuels

International Nuclear Information System (INIS)

Murto, Pauli; Nese, Gjermund

2002-01-01

We consider energy investment, when a choice has to be made between fossil fuel and biomass fired production technologies. A dynamic model is presented to illustrate the effect of the different degrees of input price uncertainty on the choice of technology and the timing of the investment. It is shown that when the choice of technology is irreversible, it may be optimal to postpone the investment even if it would otherwise be optimal to invest in one or both of the plant types. We provide a numerical example based on cost, estimates of two different power plant types. (author)

SU-E-T-312: Dosimetric Consideration for the Agility MLC When Planning Rotational SRT/SBRT Treatments

Energy Technology Data Exchange (ETDEWEB)

Kong, X; Harris, J; Spitznagel, D; Walker, J [Avera Medical Group - Radiation Oncology, Sioux Falls, SD (United States)

2015-06-15

Purpose: To analyze the radiation transmission of the Agility MLC and make recommendation based on the MLC dosimetric characteristics for SRT, SBRT and VMAT planning Method and Materials: Agility MLC is the newest model from Elekta and has no back up diaphragm behind leaves for this generation. Leaves are single focused with rounded end; composed of leafs each 0.5cm wide, 9cm thick, constructed from tungsten alloy and provide low transmission <0.5%. Total radiation transmission from leaves and diaphragm is <0.13%. A 360degree arc was generated using iCom tools; leaves were programmed closed while keeping the diaphragm fully open to maximize the MLC transmission effect. Gafchromic EBT films were sandwiched between 4cm of solid water and situated at midplane to take dose measurement. 5000MU was delivered using 6MV VersaHD, various collimator angles, and a 5cm central axis offset was tested also. Films were scanned with Epson 10000XL scanner and analyzed using DoseLab Pro. Results: Due to the rounded leaf end and nature of rotation therapy, dose accumulation through the leaf gap is significant. By offsetting the leaf gap from central axis, this accumulation can be greatly reduced. There are dark bands showing accumulation of interleaf transmission which is improved by increasing collimator angle from 0 to 45dgree. However for 45 degree, in most cases, there are larger volumes sweeping under MLC alone, which needs considered planning. Conclusions: While inter-leaf leakage is minimized by using collimator angles greater than 0 degrees, the location of the leaf gap must also be managed. The leaf gap position becomes critically important when the treatment area is off axis such is the case when more than one PTV is being treated. With VMAT for SRT, SBRT becoming a more popular planning technique, special attention needs to be paid when initially setting up the field geometry.

Publicly announced access recommendations and consumers’ service time choices with uncertain congestion

NARCIS (Netherlands)

Han, Q.; Benedict, G.C.; Dellaert, W.; van Raaij, W.F.; Timmermans, H.J.P.

2014-01-01

This article investigates consumers' anticipation of other consumers' service time choices in capacity-constrained services and how this is affected by publicly announced access recommendations. Empirical results from an experiment with simulated congestion experiences show that the impact of

Publicly announced access recommendations and consumers' service time choices with uncertain congestion

NARCIS (Netherlands)

Han, Q.; Dellaert, B.G.C.; Raaij, W.F.V.; Timmermans, H.J.P.

2014-01-01

This article investigates consumers' anticipation of other consumers' service time choices in capacity-constrained services and how this is affected by publicly announced access recommendations. Empirical results from an experiment with simulated congestion experiences show that the impact of

Inconsistency in serial choice decision and motor reaction times dissociate in younger and older adults

OpenAIRE

Bunce, D; MacDonald, SWS; Hultsch, DF

2004-01-01

Intraindividual variability (inconsistency) in reaction time (RT) latencies was investigated in a group of younger (M = 25.46 years) and older (M = 69.29 years) men. Both groups performed 300 trials in 2-, 4-, and 8-choice RT conditions where RTs for decision and motor components of the task were recorded separately. A dissociation was evident in that inconsistency was greater in older adults for decision RTs when task demands relating to the number of choices and fatigue arising from time-on...

Response time in online stated choice experiments

DEFF Research Database (Denmark)

Campbell, Danny; Mørkbak, Morten Raun; Olsen, Søren Bøye

2017-01-01

In this paper, we use paradata relating to the length of time respondents required in a self-administered online stated preference surveys. Although this issue has been previously explored, there is little guidance on how to identify and deal with ‘fast’ and ‘slow’ respondents. In this paper, we...... in Denmark. Results from our analysis corroborate that response latency has a bearing on the estimates of utility coefficients and the error variance. Although the results highlight the non-triviality of identifying fast and slow respondents, they signal the need to estimate a large number of candidate...... models to identify the most appropriate ‘fast’ and ‘slow’ thresholds. Not doing so is likely to lead to an inferior model and has repercussions for marginal willingness to pay estimates and choice predictions....

Errors in Postural Preparation Lead to Increased Choice Reaction Times for Step Initiation in Older Adults

Science.gov (United States)

Nutt, John G.; Horak, Fay B.

2011-01-01

Background. This study asked whether older adults were more likely than younger adults to err in the initial direction of their anticipatory postural adjustment (APA) prior to a step (indicating a motor program error), whether initial motor program errors accounted for reaction time differences for step initiation, and whether initial motor program errors were linked to inhibitory failure. Methods. In a stepping task with choice reaction time and simple reaction time conditions, we measured forces under the feet to quantify APA onset and step latency and we used body kinematics to quantify forward movement of center of mass and length of first step. Results. Trials with APA errors were almost three times as common for older adults as for younger adults, and they were nine times more likely in choice reaction time trials than in simple reaction time trials. In trials with APA errors, step latency was delayed, correlation between APA onset and step latency was diminished, and forward motion of the center of mass prior to the step was increased. Participants with more APA errors tended to have worse Stroop interference scores, regardless of age. Conclusions. The results support the hypothesis that findings of slow choice reaction time step initiation in older adults are attributable to inclusion of trials with incorrect initial motor preparation and that these errors are caused by deficits in response inhibition. By extension, the results also suggest that mixing of trials with correct and incorrect initial motor preparation might explain apparent choice reaction time slowing with age in upper limb tasks. PMID:21498431

Removal of antibiotics in wastewater: Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process.

Science.gov (United States)

Kim, Sungpyo; Eichhorn, Peter; Jensen, James N; Weber, A Scott; Aga, Diana S

2005-08-01

A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was evaluated at tetracycline concentrations found in the influent of the wastewater treatment plant (WWTP) where the activated sludge was obtained. The concentrations of tetracyclines in the influent of the WWTP ranged from 0.1 to 0.6 microg/L. Three different operating conditions were applied during the study (phase 1-HRT: 24 h and SRT: 10 days; phase 2-HRT: 7.4 h and SRT: 10 days; and phase 3-HRT: 7.4 h and SRT: 3 days). The removal efficiency of tetracycline in phase 3 (78.4 +/- 7.1%) was significantly lower than that observed in phase 1 (86.4 +/- 8.7%) and phase 2 (85.1 +/- 5.4%) at the 95% confidence level. The reduction of SRT in phase 3 while maintaining a constant HRT decreased tetracycline removal efficiency. Sorption kinetics reached equilibrium within 24 h. Batch equilibrium experiments yielded an adsorption coefficient (Kads) of 8400 +/- 500 mL/g and a desorption coefficient (Kdes) of 22 600 +/- 2200 mL/g. No evidence of biodegradation for tetracycline was observed during the biodegradability test, and sorption was found to be the principal removal mechanism of tetracycline in activated sludge.

SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

International Nuclear Information System (INIS)

Ding, C; Hrycushko, B; Jiang, S; Meyer, J; Timmerman, R

2014-01-01

Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm 3 ) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan, the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment

Time use choices and healthy body weight: A multivariate analysis of data from the American Time use Survey

Directory of Open Access Journals (Sweden)

Stevens Robert B

2011-08-01

Full Text Available Abstract Background We examine the relationship between time use choices and healthy body weight as measured by survey respondents' body mass index (BMI. Using data from the 2006 and 2007 American Time Use Surveys, we expand upon earlier research by including more detailed measures of time spent eating as well as measures of physical activity time and sedentary time. We also estimate three alternative models that relate time use to BMI. Results Our results suggest that time use and BMI are simultaneously determined. The preferred empirical model reveals evidence of an inverse relationship between time spent eating and BMI for women and men. In contrast, time spent drinking beverages while simultaneously doing other things and time spent watching television/videos are positively linked to BMI. For women only, time spent in food preparation and clean-up is inversely related to BMI while for men only, time spent sleeping is inversely related to BMI. Models that include grocery prices, opportunity costs of time, and nonwage income reveal that as these economic variables increase, BMI declines. Conclusions In this large, nationally representative data set, our analyses that correct for time use endogeneity reveal that the Americans' time use decisions have implications for their BMI. The analyses suggest that both eating time and context (i.e., while doing other tasks simultaneously matters as does time spent in food preparation, and time spent in sedentary activities. Reduced form models suggest that shifts in grocery prices, opportunity costs of time, and nonwage income may be contributing to alterations in time use patterns and food choices that have implications for BMI.

Choice reaction time in patients with post-operative cognitive dysfunction

DEFF Research Database (Denmark)

Steinmetz, J.; Rasmussen, L.S.

2008-01-01

BACKGROUND: Post-operative cognitive dysfunction (POCD) is detected by administration of a neuropsychological test battery. Reaction time testing is at present not included as a standard test. Choice reaction time (CRT) data from the first International Study of Post-operative Cognitive Dysfunction...... in nine countries. CRT was measured 52 times using the four boxes test. Patients performed the test before surgery (n=1083), at 1 week (n=926) and at 3 months (n=852) post-operatively. CRT for the individual patient was determined as the median time of correct responses. The usefulness of the CRT...... had a significantly longer CRT. ROC curves revealed that a reaction time of 813 ms was the most appropriate cut-off at 1 week and 762 ms at 3 months but the positive predictive value for POCD was low: 34.4% and 14.7%, respectively. CONCLUSIONS: Post-operative cognitive dysfunction is associated...

The link between response time and preference, variance and processing heterogeneity in stated choice experiments

DEFF Research Database (Denmark)

Campbell, Danny; Mørkbak, Morten Raun; Olsen, Søren Bøye

2018-01-01

In this article we utilize the time respondents require to answer a self-administered online stated preference survey. While the effects of response time have been previously explored, this article proposes a different approach that explicitly recognizes the highly equivocal relationship between ...... between response time and utility coefficients, error variance and processing strategies. Our results thus emphasize the importance of considering response time when modeling stated choice data....... response time and respondents' choices. In particular, we attempt to disentangle preference, variance and processing heterogeneity and explore whether response time helps to explain these three types of heterogeneity. For this, we divide the data (ordered by response time) into approximately equal......-sized subsets, and then derive different class membership probabilities for each subset. We estimate a large number of candidate models and subsequently conduct a frequentist-based model averaging approach using information criteria to derive weights of evidence for each model. Our findings show a clear link...

Decision-Tree Models of Categorization Response Times, Choice Proportions, and Typicality Judgments

Science.gov (United States)

Lafond, Daniel; Lacouture, Yves; Cohen, Andrew L.

2009-01-01

The authors present 3 decision-tree models of categorization adapted from T. Trabasso, H. Rollins, and E. Shaughnessy (1971) and use them to provide a quantitative account of categorization response times, choice proportions, and typicality judgments at the individual-participant level. In Experiment 1, the decision-tree models were fit to…

Individual Differences in Impulsive Choice and Timing in Rats

Science.gov (United States)

Galtress, Tiffany; Garcia, Ana; Kirkpatrick, Kimberly

2012-01-01

Individual differences in impulsive choice behavior have been linked to a variety of behavioral problems including substance abuse, smoking, gambling, and poor financial decision-making. Given the potential importance of individual differences in impulsive choice as a predictor of behavioral problems, the present study sought to measure the extent…

Visual Attention During Brand Choice : The Impact of Time Pressure and Task Motivation

NARCIS (Netherlands)

Pieters, R.; Warlop, L.

1998-01-01

Measures derived from eye-movement data reveal that during brand choice consumers adapt to time pressure by accelerating the visual scanning sequence, by filtering information and by changing their scanning strategy. In addition, consumers with high task motivation filter brand information less and

Analysis of inertial choice behaviour based expected and experienced savings from a real-world route choice experiment

NARCIS (Netherlands)

Vreeswijk, J.D.; Rakha, H.; Van Berkum, E.; Van Arem, B.

2014-01-01

In the context of route choice, inertial behaviour shows that drivers make choices that are satisfactory rather than optimal. Consequently, drivers may not necessarily alter their choice when confronted with a travel time increase on the current choice or a travel time decrease of a choice

Influence of solids retention time on membrane fouling: characterization of extracellular polymeric substances and soluble microbial products.

Science.gov (United States)

Duan, Liang; Tian, Zhiyong; Song, Yonghui; Jiang, Wei; Tian, Yuan; Li, Shan

2015-01-01

The objective of this study was to investigate the influence of solids retention time (SRT) on membrane fouling and the characteristics of biomacromolecules. Four identical laboratory-scale membrane bioreactors (MBRs) were operated with SRTs for 10, 20, 40 and 80 days. The results indicated that membrane fouling occurred faster and more readily under short SRTs. Fouling resistance was the primary source of filtration resistance. The modified fouling index (MFI) results suggested that the more ready fouling at short SRTs could be attributed to higher concentrations of soluble microbial products (SMP). Fourier transform infrared (FTIR) spectra indicated that the SRT had a weak influence on the functional groups of the total extracellular polymeric substances (TEPS) and SMP. However, the MBR under a short SRT had more low-molecular-weight (MW) compounds (100 kDa). Aromatic protein and tryptophan protein-like substances were the dominant groups in the TEPS and SMP, respectively.

Effect of solids retention time and temperature on waste activated sludge hydrolysis and short-chain fatty acids accumulation under alkaline conditions in continuous-flow reactors.

Science.gov (United States)

Feng, Leiyu; Wang, Hua; Chen, Yinguang; Wang, Qin

2009-01-01

The effects of solids retention time (SRT) and temperature on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation were investigated in a series of continuous-flow reactors at pH 10. The experimental results showed that the increase of either SRT or temperature benefited the hydrolysis of WAS and the production of SCFAs. The changes in SRT gave also impact on the percentage of acetic and propionic acids in the fermentative SCFAs, but little influence on that of the slightly long-chain SCFAs, such as n-butyric, iso-butyric, n-valeric and iso-valeric acids. Compared with the control (pH unadjusted) experiment, at SRT of 12d and temperature of 20 degrees C the concentration of SCFAs produced at pH 10 increased from 261.2 to 933.5mg COD/L, and the propionic acid percentage improved from 11.7 to 16.0%. It can be concluded from this investigation that the efficient continuous production of SCFAs at pH 10 is feasible.

Influence of Two Different Exercise Programs on Physical Fitness and Cognitive Performance in Active Older Adults: Functional Resistance-Band Exercises vs. Recreational Oriented Exercises

Directory of Open Access Journals (Sweden)

Hernán Ponce-Bravo, Christian Ponce, Belén Feriche, Paulino Padial

2015-12-01

Full Text Available This study examines the impact of a resistance-band functional exercise program, compared with a recreational exercise program, on physical fitness and reaction times in persons older than 60 years. Fifty-four community-dwelling volunteers (71.76 ± 6.02 years were assigned to a specific exercise program: Functional activity program (focused on resistance-band multi-joint activities; experimental group, EG, or recreational physical activity program (with gross motor activities of ludic content; control group, CG. Before and after the intervention, we determined cognitive capacity in terms of simple reaction time (S-RT, choice reaction time (C-RT and fitness. In both groups physical performance improved, though this improvement was more marked in the EG for grip strength, arm strength and gross motor abilities (p < 0.05. Reaction times were better only in EG (S-RT = 10.70%, C-RT = 14.34%; p < 0.05 after the corresponding physical training intervention. The training period showed no effect on the moderate relationship between both RT and gross motor abilities in the CG, whereas the EG displayed an enhanced relationship between S-RT and grip-strength as well as the C-RT with arm strength and aerobic capacity (r ~ 0.457; p < 0.05. Our findings indicate that a functional exercise program using a resistance band improves fitness and cognitive performance in healthy older adults.

Time optimized path-choice in the termite hunting ant Megaponera analis.

Science.gov (United States)

Frank, Erik T; Hönle, Philipp O; Linsenmair, K Eduard

2018-05-10

Trail network systems among ants have received a lot of scientific attention due to their various applications in problem solving of networks. Recent studies have shown that ants select the fastest available path when facing different velocities on different substrates, rather than the shortest distance. The progress of decision-making by these ants is determined by pheromone-based maintenance of paths, which is a collective decision. However, path optimization through individual decision-making remains mostly unexplored. Here we present the first study of time-optimized path selection via individual decision-making by scout ants. Megaponera analis scouts search for termite foraging sites and lead highly organized raid columns to them. The path of the scout determines the path of the column. Through installation of artificial roads around M. analis nests we were able to influence the pathway choice of the raids. After road installation 59% of all recorded raids took place completely or partly on the road, instead of the direct, i.e. distance-optimized, path through grass from the nest to the termites. The raid velocity on the road was more than double the grass velocity, the detour thus saved 34.77±23.01% of the travel time compared to a hypothetical direct path. The pathway choice of the ants was similar to a mathematical model of least time allowing us to hypothesize the underlying mechanisms regulating the behavior. Our results highlight the importance of individual decision-making in the foraging behavior of ants and show a new procedure of pathway optimization. © 2018. Published by The Company of Biologists Ltd.

Right- and left-brain hemisphere. Rhythm in reaction time to light signals is task-load-dependent: age, gender, and handgrip strength rhythm comparisons.

Science.gov (United States)

Reinberg, Alain; Bicakova-Rocher, Alena; Mechkouri, Mohamed; Ashkenazi, Israel

2002-11-01

In healthy mature subjects simple reaction time (SRT) to a single light signal (an easy task) is associated with a prominent rhythm with tau = 24 h of dominant (DH) as well as nondominant (NDH) hand performance, while three-choice reaction time (CRT), a complex task, is associated with tau = 24 h of the DH but tau gender on the difference in tau of the NDH and DH, as it relates to the corresponding cortical hemisphere of the brain, in comparison to the rhythm in handgrip strength. Healthy subjects, 9 (5 M and 4 F) adolescents 10-16 yr of age and 15 (8 M and 7 F) adults 18-67 yr of age, active between 08:00 +/- 1 h and 23:00 +/- 1:30 h and free of alcohol, tobacco, and drug consumption volunteered. Data were gathered longitudinally at home and work 4-7 times daily for 11-20 d. At each test time the following variables were assessed: grip strength of both hands (Dynamometer: Colin-Gentile, Paris, France); single reaction time to a yellow signal (SRT); and CRT to randomized yellow, red, or green signal series with varying instruction from test to test (Psycholog-24: Biophyderm, France). Rhythms in the performance in SRT, CRT, and handgrip strength of both DH and NDH were explored. The sleep-wake rhythm was assessed by sleep-logs, and in a subset of 14 subjects it was also assessed by wrist actigraphy (Mini-Motionlogger: AMI, Ardsley NY). Exploration of the prominent period tau of time series was achieved by a special power spectra analysis for unequally spaced data. Cosinor analysis was used to quantify the rhythm amplitude A and rhythm-adjusted mean M of the power spectral analysis determined trial tau. A 24h sleep-wake rhythm was detected in almost all cases. In adults, a prominent tau of 24 h characterized the performance of the easy task by both the DH and NDH. In adults a prominent tau of 24 h was also detected in the complex CRT task performed by the DH, but for the NDH the tau was gender-related but was age-related since it was seldom observed in adolescent

How flexible is flexible? Accounting for the effect of rescheduling possibilities in choice of departure time for work trips

DEFF Research Database (Denmark)

Thorhauge, Mikkel; Cherchi, Elisabetta; Rich, Jeppe

2016-01-01

for each of these activities. We then built a stated preference experiment to infer preferences on departure time choice, and estimated a mixed logit model, based on the scheduling model, to account for the effects of daily activity schedules and their constraints. Our results show that measuring......In departure time studies it is crucial to ascertain whether or not individuals are flexible in their choices. Previous studies have found that individuals with flexible work times have a lower value of time for late arrivals. Flexibility is usually measured in terms of flexible work start time...... is not accounted for....

Value of time determination for the city of Alexandria based on a disaggregate binary mode choice model

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Mounir Mahmoud Moghazy Abdel-Aal

2017-12-01

Full Text Available In the travel demand modeling field, mode choice is the most important decision that affects the resulted road congestion. The behavioral nature of the disaggregate models and the associated advantages of such models over aggregate models have led to their extensive use. This paper proposes a framework to determine the value of time (VoT for the city of Alexandria through calibrating a disaggregate linear-in parameter utility-based binary logit mode choice model of the city. The mode attributes (travel time and travel cost along with traveler attributes (car ownership and income were selected as the utility attributes of the basic model formulation which included 5 models. Three additional alternative utility formulations based on the transformation of the mode attributes including relative travel cost (cost divided by income and log (travel time and the combination of the two transformations together were introduced. The parameter estimation procedure was based on the likelihood maximization technique and was performed in EXCEL. Out of 20 models estimated, only 2 models are considered successful in terms of the parameters estimates correct signs and the magnitude of their significance (t-statistics value. The determination of the VoT serves also in the model validation. The best two models estimated the value of time at LE 11.30/hr and LE 14.50/hr with a relative error of +3.7% and +33.0%, respectively, of the hourly salary of LE 10.9/hr. The proposed two models prove to be sensitive to trip time and income levels as factors affecting the choice mechanism. The sensitivity analysis was performed and proved the model with higher relative error is marginally more robust. Keywords: Transportation modeling, Binary mode choice, Parameter estimation, Value of time, Likelihood maximization, Sensitivity analysis

The effect of solids retention times on the characterization of extracellular polymeric substances and soluble microbial products in a submerged membrane bioreactor.

Science.gov (United States)

Duan, Liang; Song, Yonghui; Yu, Huibin; Xia, Siqing; Hermanowicz, Slawomir W

2014-07-01

In this study, the effect of solids retention times (SRTs) on extracellular polymeric substances (EPS) and soluble microbial products (SMPs) were investigated in a membrane bioreactor (MBR) at SRTs of 10, 5 and 3 days. The results showed that more carbohydrates and proteins were accumulated at short SRT, which can due to the higher biomass activity in the reactor. The molecular weight (MW) distribution analysis suggested that macromolecules (MW>30 kDa) and small molecules (MW<1 kDa) were the dominant fraction of EPS and SMP, respectively. The reactor at shorter SRT had more small molecules and less macromolecules of carbohydrates. The MW distribution of total organic carbon (TOC) suggested that other organic moieties were exuded by microbes into the solution. The shorter SRT had more undefined microbial by-product-like substances and different O − H bonds in hydroxyl functional groups. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impairment of willed actions and use of advance information for movement preparation in schizophrenia

Science.gov (United States)

Fuller, R.; Jahanshahi, M.

1999-01-01

OBJECTIVES—To assess willed actions in patients with schizophrenia using reaction time (RT) tasks that differ in the degree to which they involve volitionally controlled versus stimulus driven responses.
METHODS—Ten patients diagnosed with schizophrenia and 13 normal controls of comparable age were tested. Subjects performed a visual simple RT (SRT), an uncued four choice reaction time (CRT), and a fully cued four choice RT task. A stimulus 1(S1)−stimulus 2(S2) paradigm was used. The warning signal/precue (S1) preceded the imperative stimulus (S2) by either 0 (no warning signal or precue) 200, 800, 1600, or 3200ms.
RESULTS—The patients with schizophrenia had significantly slower RTs and movement times than normal subjects across all RT tasks. The unwarned SRT trials were significantly faster than the uncued CRT trials for both groups. For both groups, fully cued CRTs were significantly faster than the uncued CRTs. However, the S1−S2 interval had a differential effect on CRTs in the two groups. For the normal subjects fully cued CRTs and SRTs were equivalent when S1-S2 intervals were 800 ms or longer. A similar pattern of effects was not seen in the patients with schizophrenia, for whom the fully cued CRT were unexpectedly equivalent to SRT for the 200 ms interval and expectedly for the 1600 ms S1-S2 interval, but not the 3200 or 800 ms intervals.
CONCLUSIONS—Patients with schizophrenia were able to use advance information inherent in SRT or provided by the precue in fully cued CRT to speed up RT relative to uncued CRT. However, in the latter task, in which the volitional demands of preprogramming are higher since a different response has to be prepared on each trial, patients showed some unusual and inconsistent interval effects suggesting instability of attentional set. It is possible that future studies using RT tasks with higher volitional demands in patients with predominance of negative signs may disclose greater deficits in willed action in

Motherhood: From rights to choices

Directory of Open Access Journals (Sweden)

Renata Salecl

2010-01-01

Full Text Available Motherhood has been perceived as choice in the developed world after the liberalisation of abortion. However, this choice can be extremely anxiety provoking for women, especially in times when the ideology of choice dominates our lives in all possible ways. The paper shows how psychotherapy and psychoanalysis look at this anxiety, it reflects on how family relations are often the traumatic kernel behind this choice, and how the changes that women experience in today's times contribute to the increase of anxiety related to reproduction.

Cerebral activation related to implicit sequence learning in a Double Serial Reaction Time task

NARCIS (Netherlands)

van der Graaf, FHCE; Maguire, RP; Leenders, KL; de Jong, BM

2006-01-01

Using functional magnetic resonance imaging (fMRI), we examined the distribution of cerebral activations related to implicitly learning a series of fixed stimulus-response combinations. In a novel - bimanual - variant of the Serial Reaction Time task (SRT), simultaneous finger movements of the two

Perception bias in route choice

NARCIS (Netherlands)

Vreeswijk, Jacob Dirk; Thomas, Tom; van Berkum, Eric C.; van Arem, Bart

2014-01-01

Travel time is probably one of the most studied attributes in route choice. Recently, perception of travel time received more attention as several studies have shown its importance in explaining route choice behavior. In particular, travel time estimates by travelers appear to be biased against

Professional Aspirations among Pre-Service Teachers: Personal Responsibility, Time Perspectives, and Career Choice Satisfaction

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Eren, Altay

2017-01-01

Exploring the direct and indirect effects of pre-service teachers' sense of personal responsibility on their professional aspirations through affective (i.e., career choice satisfaction) and cognitive (i.e., time perspectives) variables may enable teacher educators and policy makers to better describe the factors influencing teacher development in…

The influence of solid retention time on IFAS-MBR systems: Assessment of nitrous oxide emission.

Science.gov (United States)

Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Laudicina, Vito Armando; Di Trapani, Daniele

2017-12-01

The aim of the present study was to investigate the nitrous oxide (N 2 O) emissions from a moving bed based Integrated Fixed Film Activated Sludge (IFAS) - membrane bioreactor (MBR) pilot plant, designed according to the University of Cape Town (UCT) layout. The experimental campaign had a duration of 110 days and was characterized by three different sludge retention time (SRT) values (∞, 30 d and 15 d). Results highlighted that N 2 O concentrations decreased when the biofilm concentrations increased within the aerobic reactor. Results have shown an increase of N 2 O with the decrease of SRT. Specifically, an increase of N 2 O-N emission factor occurred with the decrease of the SRT (0.13%, 0.21% and 0.76% of influent nitrogen for SRT = ∞, SRT = 30 d and SRT = 15 d, respectively). Moreover, the MBR tank resulted the key emission source (up to 70% of the total N 2 O emission during SRT = ∞ period) whereas the highest N 2 O production occurred in the anoxic reactor. Moreover, N 2 O concentrations measured in the permeate flow were not negligible, thus highlighting its potential detrimental contribution for the receiving water body. The role of each plant reactor as N 2 O-N producer/consumer varies with the SRT variation, indeed the aerobic reactor was a N 2 O consumer at SRT = ∞ and a producer at SRT = 30 d. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characteristics and fates of soluble microbial products in ceramic membrane bioreactor at various sludge retention times.

Science.gov (United States)

Shin, Hang-Sik; Kang, Seok-Tae

2003-01-01

The formation and fate of soluble microbial products (SMP) in membrane bioreactor (MBR) was investigated at various sludge retention times (SRT) for 170 days. The SMP concentration was estimated by feeding glucose, which could be completely degraded, and by measuring the dissolved organic carbon (DOC) of the effluent from MBR. Under the conditions of SRT of 20 days, influent DOC of 112 mg/l and HRT of 6 h, the produced SMP was 4.7 mg DOC/l of which 57% was removed or retained by the membrane. DOC of MBR supernatant increased during 100 days and then gradually decreased. Specific UV absorbance showed that the accumulated compounds had a portion of larger, more aromatic, more hydrophobic and double-bond-rich organics, which originated from the decayed biomass. Molecular weight distributions of SMP in MBR supernatant showed that the acclimated microorganisms in a long SRT could decompose high molecular weight organics, it caused the shift of molecular weight distributions of SMP to a lower range. During the operation period, enumeration of active cells in the MBR showed that microbial inhibitions by accumulated SMP was not observed.

A Departure Time Choice for Morning Commute Considering Train Capacity of a Rail Transit Line

OpenAIRE

Jia Feng; Baohua Mao; Zhijie Chen; Yun Bai; Minggao Li

2013-01-01

Every commuter utilizing urban rail transit decides the departure time from home to a station according to individual judgment for the biggest possibility to board a train as soon as possible after the arrival. Therefore, the departure time choice behavior of the commuters is complicated especially when the transport capacity of this transit line cannot meet the travel demands of its users in rush hour. This research first develops a travel cost function mainly considering the travel time to ...

Two-relaxation-time lattice Boltzmann method and its application to advective-diffusive-reactive transport

Science.gov (United States)

Yan, Zhifeng; Yang, Xiaofan; Li, Siliang; Hilpert, Markus

2017-11-01

The lattice Boltzmann method (LBM) based on single-relaxation-time (SRT) or multiple-relaxation-time (MRT) collision operators is widely used in simulating flow and transport phenomena. The LBM based on two-relaxation-time (TRT) collision operators possesses strengths from the SRT and MRT LBMs, such as its simple implementation and good numerical stability, although tedious mathematical derivations and presentations of the TRT LBM hinder its application to a broad range of flow and transport phenomena. This paper describes the TRT LBM clearly and provides a pseudocode for easy implementation. Various transport phenomena were simulated using the TRT LBM to illustrate its applications in subsurface environments. These phenomena include advection-diffusion in uniform flow, Taylor dispersion in a pipe, solute transport in a packed column, reactive transport in uniform flow, and bacterial chemotaxis in porous media. The TRT LBM demonstrated good numerical performance in terms of accuracy and stability in predicting these transport phenomena. Therefore, the TRT LBM is a powerful tool to simulate various geophysical and biogeochemical processes in subsurface environments.

Perceptions of public transport travel time and their effect on choice-sets among car drivers

NARCIS (Netherlands)

N.J.A. van Exel (Job); P. Rietveld (Piet)

2010-01-01

textabstractCar drivers' perceptions of the quality of alternative travel modes have been identified as a barrier for including these alternatives in their choice sets. The present study investigated the accuracy of car drivers' perceptions of public transport (PT) travel time and the potential

Not all choices are created equal: Task-relevant choices enhance motor learning compared to task-irrelevant choices.

Science.gov (United States)

Carter, Michael J; Ste-Marie, Diane M

2017-12-01

Lewthwaite et al. (2015) reported that the learning benefits of exercising choice (i.e., their self-controlled condition) are not restricted to task-relevant features (e.g., feedback). They found that choosing one's golf ball color (Exp. 1) or choosing which of two tasks to perform at a later time plus which of two artworks to hang (Exp. 2) resulted in better retention than did being denied these same choices (i.e., yoked condition). The researchers concluded that the learning benefits derived from choice, whether irrelevant or relevant to the to-be-learned task, are predominantly motivational because choice is intrinsically rewarding and satisfies basic psychological needs. However, the absence of a group that made task-relevant choices and the lack of psychological measures significantly weakened their conclusions. Here, we investigated how task-relevant and task-irrelevant choices affect motor-skill learning. Participants practiced a spatiotemporal motor task in either a task-relevant group (choice over feedback schedule), a task-irrelevant group (choice over the color of an arm-wrap plus game selection), or a no-choice group. The results showed significantly greater learning in the task-relevant group than in both the task-irrelevant and no-choice groups, who did not differ significantly. Critically, these learning differences were not attributed to differences in perceptions of competence or autonomy, but instead to superior error-estimation abilities. These results challenge the perspective that motivational influences are the root cause of self-controlled learning advantages. Instead, the findings add to the growing evidence highlighting that the informational value gained from task-relevant choices makes a greater relative contribution to these advantages than motivational influences do.

Features of real-time systems

OpenAIRE

Зинченко, Сергей Валериевич; Зинченко, Валерий Петрович

2017-01-01

The purpose of the work is to analyze the features and functioning of the RTS, RT operating systems (RTOS) and the development of applied programs (AP) for RTS; RTS standards; characteristics and analysis of the RTOS; problems of extensions of RT based on Linux and Windows.The main differences between the RTOS and the general purpose OS are shown: the main task is to have time to react to events at the site; an RTOS is a tool for creating a specific SRT. The following characteristic functions...

Resolving the paradox of suboptimal choice.

Science.gov (United States)

Zentall, Thomas R

2016-01-01

When humans engage in commercial (totally probabilistic) gambling they are making suboptimal choices because the return is generally less than the investment. This review (a) examines the literature on pigeon suboptimal choice, (b) describes the conditions under which it occurs, (c) identifies the mechanisms that appear to be responsible for the effect, and (d) suggests that similar processes may be able to account for analogous suboptimal choice when humans engage in commercial gambling. Pigeons show suboptimal choice when they choose between 1 alternative that 20% of the time provides them with a signal that they will always get fed or 80% of the time with a signal that they will not get fed (overall 20% reinforcement) and a second alternative that 100% of the time provides them with a signal that they will get fed 50% of the time (overall 50% reinforcement). The pigeons' strong preference for the suboptimal choice was investigated in a series of experiments that found the preference for the suboptimal alternative was determined by the value of the signal that predicted reinforcement, rather its frequency and that the frequency of the signal that predicted nonreinforcement had little effect on the suboptimal choice. Paradoxically, this account makes the prediction that pigeons will be indifferent between an alternative that 50% of the time provides a fully predictive stimulus for reinforcement and an alternative that 100% of the time provides a fully predictive stimulus for reinforcement. The similarities and differences of this suboptimal choice task to human gambling are discussed. (c) 2016 APA, all rights reserved).

Consumer choice of theme parks : a conjoint choice model of seasonality effects and variety seeking behavior

NARCIS (Netherlands)

Kemperman, A.D.A.M.; Borgers, A.W.J.; Oppewal, H.; Timmermans, H.J.P.

2000-01-01

Most existing mathematical models of tourist choice behavior assume that individuals' preferences for choice alternatives remain invariant over time. Although the assumption of invariant preference functions may be reasonable in some choice contexts, this study examines the hypothesis that

Factors Influencing Teaching Choice, Professional Plans about Teaching, and Future Time Perspective: A Mediational Analysis

Science.gov (United States)

Eren, Altay; Tezel, Kadir Vefa

2010-01-01

This study aimed to examine the mediating role of prospective English teachers' future time perspectives in relation to their motivations for teaching, beliefs about the profession, career choice satisfaction, and professional plans. A total of 423 prospective English teachers voluntarily participated in the study. The mediating role of the future…

Genome analysis of urease positive Serratia marcescens, co-producing SRT-2 and AAC(6')-Ic with multidrug efflux pumps for antimicrobial resistance.

Science.gov (United States)

Srinivasan, Vijaya Bharathi; Rajamohan, Govindan

2018-04-05

In this study, we present the genome sequence of Serratia marcescens SM03, recovered from a human gut in India. The final assembly consists of 26 scaffolds (4620 coding DNA sequences, 5.08 Mb, 59.6% G + C ratio) and 79 tRNA genes. Analysis identified novel genes associated with lactose utilization, virulence, P-loop GTPases involved in urease production, CFA/I fimbriae apparatus and Yersinia - type CRISPR proteins. Antibiotic susceptibility testing indicated drug tolerant phenotype and inhibition assays demonstrated involvement of extrusion in resistance. Presence of enzymes SRT-2, AAC(6')-Ic, with additional Ybh transporter and EamA-like efflux pumps signifies the genetic plasticity observed in S. marcescens SM03. Copyright © 2018 Elsevier Inc. All rights reserved.

Training impulsive choices for healthy and sustainable food.

Science.gov (United States)

Veling, Harm; Chen, Zhang; Tombrock, Merel C; Verpaalen, Iris A M; Schmitz, Laura I; Dijksterhuis, Ap; Holland, Rob W

2017-06-01

Many people find it hard to change their dietary choices. Food choice often occurs impulsively, without deliberation, and it has been unclear whether impulsive food choice can be experimentally created. Across 3 exploratory and 2 confirmatory preregistered experiments we examined whether impulsive food choice can be trained. Participants were cued to make motor responses upon the presentation of, among others, healthy and sustainable food items. They subsequently selected these food items more often for actual consumption when they needed to make their choices impulsively as a result of time pressure. This effect disappeared when participants were asked to think about their choices, merely received more time to make their choices, or when choosing required attention to alternatives. Participants preferred high to low valued food items under time pressure and without time pressure, suggesting that the impulsive choices reflect valid preferences. These findings demonstrate that it is possible to train impulsive choices for food items while leaving deliberative choices for these items unaffected, and connect research on attention training to dual-process theories of decision making. The present research suggests that attention training may lead to behavioral change only when people behave impulsively. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The association between choice stepping reaction time and falls in older adults--a path analysis model

NARCIS (Netherlands)

Pijnappels, M.A.G.M.; Delbaere, K.; Sturnieks, D.L.; Lord, S.R.

2010-01-01

Background: choice stepping reaction time (CSRT) is a functional measure that has been shown to significantly discriminate older fallers from non-fallers. Objective: to investigate how physiological and cognitive factors mediate the association between CSRT performance and multiple falls by use of

Constructing food choice decisions.

Science.gov (United States)

Sobal, Jeffery; Bisogni, Carole A

2009-12-01

Food choice decisions are frequent, multifaceted, situational, dynamic, and complex and lead to food behaviors where people acquire, prepare, serve, give away, store, eat, and clean up. Many disciplines and fields examine decision making. Several classes of theories are applicable to food decision making, including social behavior, social facts, and social definition perspectives. Each offers some insights but also makes limiting assumptions that prevent fully explaining food choice decisions. We used constructionist social definition perspectives to inductively develop a food choice process model that organizes a broad scope of factors and dynamics involved in food behaviors. This food choice process model includes (1) life course events and experiences that establish a food choice trajectory through transitions, turning points, timing, and contexts; (2) influences on food choices that include cultural ideals, personal factors, resources, social factors, and present contexts; and (3) a personal system that develops food choice values, negotiates and balances values, classifies foods and situations, and forms/revises food choice strategies, scripts, and routines. The parts of the model dynamically interact to make food choice decisions leading to food behaviors. No single theory can fully explain decision making in food behavior. Multiple perspectives are needed, including constructionist thinking.

A Conceptual Model of Leisure-Time Choice Behavior.

Science.gov (United States)

Bergier, Michel J.

1981-01-01

Methods of studying the gap between predisposition and actual behavior of consumers of spectator sports is discussed. A model is drawn from the areas of behavioral sciences, consumer behavior, and leisure research. The model is constructed around the premise that choice is primarily a function of personal, product, and environmental factors. (JN)

Choice consistency and preference stability in test-retests of discrete choice experiment and open-ended willingness to pay elicitation formats

NARCIS (Netherlands)

Brouwer, R.; Logar, I.; Sheremet, O.I.

2017-01-01

This study tests the temporal stability of preferences, choices and willingness to pay (WTP) values using both discrete choice experiment (DCE) and open-ended (OE) WTP elicitation formats. The same sample is surveyed three times over the course of two years using each time the same choice sets.

Inconsistency in Serial Choice Decision and Motor Reaction Times Dissociate in Younger and Older Adults

Science.gov (United States)

Bunce, D.; MacDonald, S.W.S.; Hultsch, D.F.

2004-01-01

Intraindividual variability (inconsistency) in reaction time (RT) latencies was investigated in a group of younger (M=25.46 years) and older (M=69.29 years) men. Both groups performed 300 trials in 2-, 4-, and 8-choice RT conditions where RTs for decision and motor components of the task were recorded separately. A dissociation was evident in that…

Choice blindness in financial decision making

Directory of Open Access Journals (Sweden)

Owen McLaughlin

2013-09-01

Full Text Available Choice Blindness is an experimental paradigm that examines the interplay between individuals' preferences, decisions, and expectations by manipulating the relationship between intention and choice. This paper expands upon the existing Choice Blindness framework by investigating the presence of the effect in an economically significant decision context, specifically that of pension choice. In addition, it investigates a number of secondary factors hypothesized to modulate Choice Blindness, including reaction time, risk preference, and decision complexity, as well as analysing the verbal reports of non-detecting participants. The experiment was administered to 100 participants of mixed age and educational attainment. The principal finding was that no more than 37.2% of manipulated trials were detected over all conditions, a result consistent with previous Choice Blindness research. Analysis of secondary factors found that reaction time, financial sophistication and decision complexity were significant predictors of Choice Blindness detection, while content analysis of non-detecting participant responses found that 20% implied significant preference changes and 62% adhered to initial preferences. Implications of the Choice Blindness effect in the context of behavioural economics are discussed, and an agenda for further investigation of the paradigm in this context is outlined.

Purification and characterization of extracellular lipase from a new strain: Pseudomonas aeruginosa SRT 9 Purificação e caracterização de uma lipase extracelular produzida por uma nova cepa: Pseudomonas aeruginosa SRT9

Directory of Open Access Journals (Sweden)

Prita S. Borkar

2009-06-01

Full Text Available An extra cellular lipase was isolated and purified from the culture broth of Pseudomonas aeruginosa SRT 9 to apparent homogeneity using ammonium sulfate precipitation followed by chromatographic techniques on phenyl Sepharose CL- 4B and Mono Q HR 5/5 column, resulting in a purification factor of 98 fold with specific activity of 12307.8 U/mg. The molecular weight of the purified lipase was estimated by SDS-PAGE to be 29 kDa with isoelectric point of 4.5. Maximum lipase activity was observed in a wide range of temperature and pH values with optimum temperature of 55ºC and pH 6.9. The lipase preferably acted on triacylglycerols of long chain (C14-C16 fatty acids. The lipase was inhibited strongly by EDTA suggesting the enzyme might be metalloprotein. SDS and metal ions such as Hg2+, Zn2+, Cu2+, Ag2+ and Fe2+ decreased the lipase activity remarkedly. Its marked stability and activity in organic solvents suggest that this lipase is highly suitable as a biotechnological tool with a variety of applications including organo synthetic reactions and preparation of enantiomerically pure pharmaceuticals. The Km and Vmax value of the purified enzyme for triolein hydrolysis were calculated to be 1.11 mmol/L and 0.05 mmol/L/minrespectively.Uma lipase extracelular foi isolada e purificada a partir de um caldo de cultura de Pseudomonas aeruginosa SRT9 até homogeneidade visível empregando-se precipitação com sulfato de amônia, seguida de técnicas cromatográficas em colunas de fenil sefarose CL-4B e Mono Q HR 5/5, obtendo-se um fator de purificação de 98 vezes, e atividade especifica de 12307,8 U/mg. Por SDS_PAGE, estimou-se que o peso molecular da lipase purificada é 29kDa, com um ponto isoelétrico de 4,5. A lipase apresentou atividade máxima em uma ampla faixa de temperatura e pH, com ótimos a 55ºC e pH 6,9. A lípase foi mais ativa sobre triacilglicerois de cadeia longa (C14-C16. A lipase foi fortemente inibida por EDTA, o que sugere que a

Choice Overload, Satisficing Behavior, and Price Distribution in a Time Allocation Model

Directory of Open Access Journals (Sweden)

Francisco Álvarez

2014-01-01

Full Text Available Recent psychological research indicates that consumers that search exhaustively for the best option of a market product—known as maximizers—eventually feel worse than consumers who just look for something good enough—called satisficers. We formulate a time allocation model to explore the relationship between different distributions of prices of the product and the satisficing behavior and the related welfare of the consumer. We show numerically that, as the number of options becomes large, the maximizing behavior produces less and less welfare and eventually leads to choice paralysis—these are effects of choice overload—whereas satisficing conducts entail higher levels of satisfaction and do not end up in paralysis. For different price distributions, we provide consistent evidence that maximizers are better off for a low number of options, whereas satisficers are better off for a sufficiently large number of options. We also show how the optimal satisficing behavior is affected when the underlying price distribution varies. We provide evidence that the mean and the dispersion of a symmetric distribution of prices—but not the shape of the distribution—condition the satisficing behavior of consumers. We also show that this need not be the case for asymmetric distributions.

The Ising Decision Maker: a binary stochastic network for choice response time.

Science.gov (United States)

Verdonck, Stijn; Tuerlinckx, Francis

2014-07-01

The Ising Decision Maker (IDM) is a new formal model for speeded two-choice decision making derived from the stochastic Hopfield network or dynamic Ising model. On a microscopic level, it consists of 2 pools of binary stochastic neurons with pairwise interactions. Inside each pool, neurons excite each other, whereas between pools, neurons inhibit each other. The perceptual input is represented by an external excitatory field. Using methods from statistical mechanics, the high-dimensional network of neurons (microscopic level) is reduced to a two-dimensional stochastic process, describing the evolution of the mean neural activity per pool (macroscopic level). The IDM can be seen as an abstract, analytically tractable multiple attractor network model of information accumulation. In this article, the properties of the IDM are studied, the relations to existing models are discussed, and it is shown that the most important basic aspects of two-choice response time data can be reproduced. In addition, the IDM is shown to predict a variety of observed psychophysical relations such as Piéron's law, the van der Molen-Keuss effect, and Weber's law. Using Bayesian methods, the model is fitted to both simulated and real data, and its performance is compared to the Ratcliff diffusion model. (c) 2014 APA, all rights reserved.

The impact of presentation format on visual attention and choice in discrete choice experiments

DEFF Research Database (Denmark)

Mueller Loose, Simone; Orquin, Jacob Lund

in the product mock-up presentation required significantly fewer fixations and less decision time, and more within-alternative transitions were observed compared to the verbal and visual presentation formats. Attributes presented visually or at larger size had a higher impact on participants’ choices......Objectives. Discrete choice experiments in which participants choose between alternatives differing on attribute levels are an important research method for preference elicitation. In such experiments choice stimuli is typically presented in tables with verbally described attributes, in tables...... with visual attributes, or as product mock-ups simulating realistic products as close as possible. So far little is known about how presentation formats affect visual attention patterns and choice behavior. This study addresses the question by analysing visual attention and part-worth utilities in choice...

Factors affecting food choices of older adults from high and low socioeconomic groups: a discrete choice experiment.

Science.gov (United States)

Kamphuis, Carlijn B M; de Bekker-Grob, Esther W; van Lenthe, Frank J

2015-04-01

Healthiness, price, and convenience are typically indicated as important motives for food choices; however, it is largely unknown to what extent older adults from high and low socioeconomic groups differ in these underlying motives. A discrete choice experiment (DCE) is an innovative way to elicit implicit motives for food choices. The aim was to investigate differences in food motives between socioeconomic groups by means of a DCE. A DCE was carried out during a face-to-face interview among older adults as part of the Health and Living Conditions in Eindhoven and surrounding cities (GLOBE) cohort study, The Netherlands. Participants (n = 399; mean age: 63.3 y) were offered a series of choice sets about a usual dinner at home and were asked to choose in each choice set between 2 meals and an opt-out choice, with different combinations of attribute levels. We included 5 meal attributes (taste, healthiness, preparation time, travel time to shops, and price) and 3 or 4 levels for each attribute. Data were analyzed by multinomial logit models. Healthiness, taste, price, and travel time to the grocery store proved to significantly influence older adults' meal decisions; preparation time was not significant. Healthiness was the most important attribute for all of the participants. More highly educated participants rated a healthy and less expensive meal to be more important than did less educated participants. Those with a high income rated a meal that was healthy and very tasteful to be more important than did those with a lower income. Healthiness, taste, price, and travel time to grocery shops influenced older adults' meal decisions. Higher socioeconomic groups valued health more than did lower socioeconomic groups. DCEs represent a promising method to gain insight into the relative importance of motives for food choices. This trial was registered at www.isrctn.com as ISRCTN60293770. © 2015 American Society for Nutrition.

Influence of time pressure in a simple response task, a choice-by-location task, and the Simon task

NARCIS (Netherlands)

van der Lubbe, Robert Henricus Johannes; Jaśkowski, Piotr; Wauschkuhn, Bernd; Verleger, Rolf

2001-01-01

Examined the influence of strategy for a simple response task, a choice-by-location task, and the Simon task by varying time pressure in 11 Ss (mean age 28 yrs). Besides reaction time (RT) and accuracy, we measured response force and derived two measures from the event-related EEG potential to form

School Choice Marches forward

Science.gov (United States)

Butcher, Jonathan

2013-01-01

One year ago, the "Wall Street Journal" dubbed 2011 "the year of school choice," opining that "this year is shaping up as the best for reformers in a very long time." School-choice laws took great strides in 2011, both in the number of programs that succeeded across states and also in the size and scope of the adopted…

Time Is Money: The Decision Making of Smartphone High Users in Gain and Loss Intertemporal Choice.

Science.gov (United States)

Tang, Zixuan; Zhang, Huijun; Yan, An; Qu, Chen

2017-01-01

Nowadays the smartphone plays an important role in our lives. While it brings us convenience and efficiency, its overuse can cause problems. Although a great number of studies have demonstrated that people affected by substance abuse, pathological gambling, and internet addiction disorder have lower self-control than average, scarcely any study has investigated the decision making of smartphone high users by using a behavioral paradigm. The present study employed an intertemporal task, the Smartphone Addiction Inventory (SPAI) and the Barratt Impulsiveness Scale 11th version (BIS-11) to explore the decision control of smartphone high users in a sample of 125 college students. Participants were divided into three groups according to their SPAI scores. The upper third (69 or higher), middle third (from 61 to 68) and lower third (60 or lower) of scores were defined as high smartphone users, medium users and low users, respectively. We compared the percentage of small immediate reward/penalty choices in different conditions between the three groups. Relative to the low users group, high users and medium users were more inclined to request an immediate monetary reward. Moreover, for the two dimensions of time and money in intertemporal choice, high users and medium users showed a bias in intertemporal choice task among most of the time points and value magnitude compared to low users. These findings demonstrated that smartphone overuse was associated with problematic decision-making, a pattern similar to that seen in persons affected by a variety of addictions.

A Comparison of Free Time Activity Choices of Third Culture Kids in Albania and Children in the UK

Science.gov (United States)

Purdon, Anne

2018-01-01

This study aims to consider children's perspectives about free time activity choices. Through the use of drawings, favourite free time activities of third culture kids in Albania are compared with those of children in the UK. The sample comprises four boys and three girls from four to eight years from each country. Further conversations reveal…

Taste, choice and timing: Investigating resident and carer preferences for meals in aged care homes.

Science.gov (United States)

Milte, Rachel; Ratcliffe, Julie; Chen, Gang; Miller, Michelle; Crotty, Maria

2018-03-01

There has been little empirical investigation of the preferences of people living in aged care homes for food services. The aim of the present study was to elicit consumer preferences and their willingness to pay for food service in aged care homes. Current residents or their family members were invited to take part in the discrete choice experiment questionnaire administered via interview. Of the 109 eligible residents and 175 eligible family members approached for consent 121 (43%) participated, including 43 residents. Participant preferences were influenced by food taste, choice in relation to serving size, timing of meal selection, visual appeal, and additional cost. Participants indicated they would be willing to pay an additional $24 (US$18.42) per week for food which tasted excellent and $8 (US$6.14) per week to have choice in serving sizes. The study found that respondents were willing to pay a premium to receive food that met their expectations of taste, and for a high level of control over serving sizes, which has implications for the funding and provision of food and dining in long-term care in the future. © 2018 The Authors Nursing & Health Sciences Published by John Wiley & Sons Australia, Ltd.

Analysis of inertia thresholds based on real-world route choice data

NARCIS (Netherlands)

Vreeswijk, Jacob Dirk; van Berkum, Eric C.; van Arem, Bart

2014-01-01

In the context of route choice, inertial behaviour shows that drivers make choices that are satisfactory rather than optimal. Consequently, drivers may not necessarily alter their choice when confronted with a travel time increase on the current choice or a travel time decrease of a choice

Informed Choice in the German Mammography Screening Program by Education and Migrant Status: Survey among First-Time Invitees.

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Eva-Maria Berens

Full Text Available Breast cancer is the most prevalent cancer among women and mammography screening programs are seen as a key strategy to reduce breast cancer mortality. In Germany, women are invited to the population-based mammography screening program between ages 50 to 69. It is still discussed whether the benefits of mammography screening outweigh its harms. Therefore, the concept of informed choice comprising knowledge, attitude and intention has gained importance. The objective of this observational study was to assess the proportion of informed choices among women invited to the German mammography screening program for the first time. A representative sample of 17,349 women aged 50 years from a sub-region of North Rhine Westphalia was invited to participate in a postal survey. Turkish immigrant women were oversampled. The effects of education level and migration status on informed choice and its components were assessed. 5,847 (33.7% women responded to the postal questionnaire of which 4,113 were used for analyses. 31.5% of the women had sufficient knowledge. The proportion of sufficient knowledge was lower among immigrants and among women with low education levels. The proportion of women making informed choices was low (27.1%, with similar associations with education level and migration status. Women of low (OR 2.75; 95% CI 2.18-3.46 and medium education level (OR 1.49; 95% CI 1.27-1.75 were more likely to make an uninformed choice than women of high education level. Turkish immigrant women had the greatest odds for making an uninformed choice (OR 5.30, 95% CI 1.92-14.66 compared to non-immigrant women. Other immigrant women only had slightly greater odds for making an uninformed choice than non-immigrant women. As immigrant populations and women with low education level have been shown to have poor knowledge, they need special attention in measures to increase knowledge and thus informed choices.

Future perspective and healthy lifestyle choices in adulthood.

Science.gov (United States)

Tasdemir-Ozdes, Aylin; Strickland-Hughes, Carla M; Bluck, Susan; Ebner, Natalie C

2016-09-01

Regardless of age, making healthy lifestyle choices is prudent. Despite that, individuals of all ages sometimes have difficulty choosing the healthy option. We argue that individuals' view of the future and position in the life span affects their current lifestyle choices. We capture the multidimensionality of future thinking by assessing 3 types of future perspective. Younger and older men and women (N = 127) reported global future time perspective, future health perspective, and perceived importance of future health-related events. They also rated their likelihood of making healthy lifestyle choices. As predicted, older participants indicated greater intention to make healthy choices in their current life than did younger participants. Compared to younger participants, older participants reported shorter global future time perspective and anticipated worse future health but perceived future health-related events as more important. Having a positive view of one's future health and seeing future health-related events as important were related to greater intention to make healthy lifestyle choices, but greater global future time perspective was not directly related to healthy choices. However, follow-up analyses suggested that greater global future time perspective indirectly affected healthy choices via a more positive view of future health. None of these relations were moderated by age. Individuals' perspective on the future is shown to be an important multidimensional construct affecting everyday healthy lifestyle choices for both younger and older adults. Implications for encouraging healthy choices across the adult life span are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Experience in the use of teleoperated robotic equipment in the Spanish Nuclear Power Plants (S.R.T. Project)

International Nuclear Information System (INIS)

Bielza, M.; Gomez, J.; Izquierdo, J.A.; Bercedo, A.; Espallardo, J.A.; Martinez, A.; Carmena, P.; Pascual, J.L.

1998-01-01

The main objective of the Teleoperated Robotic Systems project (SRT) is the development of teleoperated robotic systems for use in the inspection, surveillance and maintenance operations in nuclear and radioactive installations. These systems make possible the reduction of the individual and collective doses of the workers that undertake these operations, as well as an increase of plant availability as it is possible to carry out specific tasks of inspection and surveillance in high radiation dose areas without to reduce the power of the installation. This project started in 1995 deciding to priorize the inspection equipment in a first phase. As a result of this work currently several semi-industrial products are available: ROBCAR, ROBICEN y ANAES. These have been installed for testing and commercial operation in Spanish nuclear installations. In this paper the experience of using these prototypes in the S.M. de Garona and Cofrentes nuclear power plants is described, as well as the improvements in the design of these systems derived from these experiences that have been incorporated to the industrial prototypes that are currently in the last phase of development. (Author)

Development and conceptual validation of a questionnaire to help contraceptive choice: CHLOE (Contraception: HeLping for wOmen's choicE).

Science.gov (United States)

Jamin, Christian Georges; Häusler, Gunther; Lobo Abascal, Paloma; Fiala, Christian; Lete Lasa, Luis Ignacio; Nappi, Rossella Elena; Micheletti, Marie-Christine; Fernández-Dorado, Ana; Pintiaux, Axelle; Chabbert-Buffet, Natalie

2017-08-01

The aim of this research was to develop a questionnaire to facilitate choice of the most appropriate contraceptive method for individual women. A literature review was conducted to identify key aspects influencing contraceptive choice and inform development of a questionnaire for online completion. Questionnaire development was overseen by a steering committee consisting of eight gynaecologists from across Europe. The initial draft underwent conceptual validation through cognitive debriefing interviews with six native English-speaking women. A qualitative content analysis was conducted to accurately identify potential issues and areas for questionnaire improvement. A revised version of the questionnaire then underwent face-to-face and online evaluation by 115 international gynaecologists/obstetricians with expertise in contraception, prior to development of a final version. The final conceptually validated Contraception: HeLping for wOmen's choicE (CHLOE) questionnaire takes ≤10 min to complete and includes three sections to elicit general information about the individual, the health conditions that might influence contraceptive choice, and the woman's needs and preferences that might influence contraceptive choice. The questionnaire captures the core aspects of personalisation, efficacy and safety, identified as key attributes influencing contraceptive choice, and consists of 24 closed-ended questions for online completion prior to a health care provider (HCP) consultation. The HCP receives a summary of the responses. The CHLOE questionnaire has been developed to help women choose the contraception that best suits their needs and situation while optimising the HCP's time.

No effects of psychosocial stress on intertemporal choice.

Directory of Open Access Journals (Sweden)

Johannes Haushofer

Full Text Available Intertemporal choices - involving decisions which trade off instant and delayed outcomes - are often made under stress. It remains unknown, however, whether and how stress affects intertemporal choice. We subjected 142 healthy male subjects to a laboratory stress or control protocol, and asked them to make a series of intertemporal choices either directly after stress, or 20 minutes later (resulting in four experimental groups. Based on theory and evidence from behavioral economics and cellular neuroscience, we predicted a bidirectional effect of stress on intertemporal choice, with increases in impatience or present bias immediately after stress, but decreases in present bias or impatience when subjects are tested 20 minutes later. However, our results show no effects of stress on intertemporal choice at either time point, and individual differences in stress reactivity (changes in stress hormone levels over time are not related to individual differences in intertemporal choice. Together, we did not find support for the hypothesis that psychosocial laboratory stressors affect intertemporal choice.

Improving the representation of modal choice into bottom-up optimization energy system models - The MoCho-TIMES model

DEFF Research Database (Denmark)

Tattini, Jacopo; Ramea, Kalai; Gargiulo, Maurizio

2018-01-01

and mathematical expressions required to develop the approach. This study develops MoCho-TIMES in the standalone transportation sector of TIMES-DK, the integrated energy system model for Denmark. The model is tested for the Business as Usual scenario and for four alternative scenarios that imply diverse......This study presents MoCho-TIMES, an original methodology for incorporating modal choice into energy-economy-environment-engineering (E4) system models. MoCho-TIMES addresses the scarce ability of E4 models to realistically depict behaviour in transport and allows for modal shift towards transit...

Elderly fallers enhance dynamic stability through anticipatory postural adjustments during a choice stepping reaction time

Directory of Open Access Journals (Sweden)

Romain Tisserand

2016-11-01

Full Text Available In the case of disequilibrium, the capacity to step quickly is critical to avoid falling for elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT, where elderly fallers (F take longer to step than elderly non-fallers (NF. However, reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA that elderly F develop in a stepping context and their consequences on the dynamic stability. 44 community-dwelling elderly subjects (20 F and 22 NF performed a CSRT where kinematics and ground reaction forces were collected. Variables were analyzed using two-way repeated measures ANOVAs. Results for F compared to NF showed that stepping time is elongated, due to a longer APA phase. During APA, they seem to use two distinct balance strategies, depending on the axis: in the anteroposterior direction, we measured a smaller backward movement and slower peak velocity of the center of pressure (CoP; in the mediolateral direction, the CoP movement was similar in amplitude and peak velocity between groups but lasted longer. The biomechanical consequence of both strategies was an increased margin of stability (MoS at foot-off, in the respective direction. By elongating their APA, elderly F use a safer balance strategy that prioritizes dynamic stability conditions instead of the objective of the task. Such a choice in balance strategy probably comes from muscular limitations and/or a higher fear of falling and paradoxically indicates an increased risk of fall.

Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

KAUST Repository

Bagchi, Samik

2014-10-19

In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different solids retention time (SRT). Rank-abundance curves showed few dominant operational taxonomic units (OTUs) and a long tail of rare OTUs in all reactors. Results revealed that there was no detectable effect of SRT (2 vs. 10 days) on Shannon diversity index and OTU richness of both dominant and rare taxa. Nonmetric multidimensional scaling analysis showed that the total, dominant, and rare bacterial taxa were highly dynamic during the entire period of stable reactor performance. Also, the rare taxa were more dynamic than the dominant taxa despite expected low invasion rates because of the use of sterile synthetic media.

Effect of solids retention time on the bioavailability of organic carbon in anaerobically digested swine waste.

Science.gov (United States)

Kinyua, Maureen N; Cunningham, Jeffrey; Ergas, Sarina J

2014-06-01

Anaerobic digestion (AD) can be used to stabilize and produce energy from livestock waste; however, digester effluents may require further treatment to remove nitrogen. This paper quantifies the effects of varying solids retention time (SRT) methane yield, volatile solids (VS) reduction and organic carbon bioavailability for denitrification during swine waste AD. Four bench-scale anaerobic digesters, with SRTs of 14, 21, 28 and 42 days, operated with swine waste feed. Effluent organic carbon bioavailability was measured using anoxic microcosms and respirometry. Excellent performance was observed for all four digesters, with >60% VS removal and CH4 yields between 0.1 and 0.3(m(3)CH4)/(kg VS added). Organic carbon in the centrate as an internal organic carbon source for denitrification supported maximum specific denitrification rates between 47 and 56(mg NO3(-)-N)/(g VSS h). The digester with the 21-day SRT had the highest CH4 yield and maximum specific denitrification rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

On the choice of lens density profile in time delay cosmography

Science.gov (United States)

Sonnenfeld, Alessandro

2018-03-01

Time delay lensing is a mature and competitive cosmological probe. However, it is limited in accuracy by the well-known problem of the mass-sheet degeneracy: too rigid assumptions on the density profile of the lens can potentially bias the inference on cosmological parameters. I investigate the degeneracy between the choice of the lens density profile and the inference on the Hubble constant, focusing on double image systems. By expanding lensing observables in terms of the local derivatives of the lens potential around the Einstein radius, and assuming circular symmetry, I show that 3 degrees of freedom in the radial direction are necessary to achieve a few per cent accuracy in the time-delay distance. Additionally, while the time delay is strongly dependent on the second derivative of the potential, observables typically used to constrain lens models in time-delay studies, such as image position and radial magnification information, are mostly sensitive to the first and third derivatives, making it very challenging to accurately determine time-delay distances with lensing data alone. Tests on mock observations show that the assumption of a power-law density profile results in a 5 per cent average bias on H0, with a 6 per cent scatter. Using a more flexible model and adding unbiased velocity dispersion constraints allows me to obtain an inference with 1 per cent accuracy. A power-law model can still provide 3 per cent accuracy if velocity dispersion measurements are used to constrain its slope. Although this study is based on the assumption of axisymmetry, its main findings can be generalized to cases with moderate ellipticity.

Behaviour of biopolymeric substances in the activated sludge of an MBR system working with high hydraulic retention time.

Science.gov (United States)

Marín, Eugenio; Pérez, Jorge I; Gómez, Miguel A

2017-10-15

This study was undertaken to analyse the activated sludge of a membrane bioreactor (MBR), the behaviour of extracellular polymeric substances (EPS) and soluble microbial products (SMP) as well as their biopolymers composition, in the activated sludge of a membrane bioreactor (MBR) and their influence on membrane fouling were analysed. For the experiment an experimental fullscale MBR working with real urban wastewater at high hydraulic retention time with a variable sludge-retention time (SRT) was used. The MBR system worked in denitrification/nitrification conformation at a constant flow rate (Q = 0.45 m 3 /h) with a recirculation flow rate of 4Q. The concentrations of SMP in the activated sludge were lower than the concentrations of EPS over the entire study, with humic substances being the main components of the two biopolymers. SMP and, more specifically, SMP carbohydrates, were the most influential biopolymers in membrane fouling, while for EPS and their components, no relation was found with fouling. The SRT and temperature were the operational variables that most influenced the SMP and EPS concentration, causing the increase of SRT and temperature a lower concentration in both biopolymers, although the effect was not the same for all the components, particularly for the EPS carbohydrates, which increased with longer SRTs. Both operational variables were also the ones most influential on the concentration of organic matter of the effluent, due to their effect on the SMP. The volatile suspended solid/total suspended solid (VSS/TSS) ratio in the activated sludge can be applied as a good indicator of the risk of membrane fouling by biopolymers in MBR systems.

SU-F-T-580: New Tumor Modeling Using 3D Gel Dosimeter for Brain Stereoctactic Radiotherpy (SRT)

International Nuclear Information System (INIS)

Chang, K; Kim, M; Kwak, J; Kim, S; Ji, Y; Cho, B; Yoon, S; Lee, S

2016-01-01

Purpose: The purpose of this study is to develop new tumor model using 3D printing with 3D dosimeter for brain stereoctactic radiotherpy (SRT). Methods: BANG"3 polymer gel was prepared and the gel-filled glass vials were irradiated with a 6 MV photon beam to acquire the calibration curve that present the change of R2 (1/T_2) value with dose. Graded doses from 0 to 12 Gy with an interval of 2 Gy were delivered. A kit for calibration of gel dosimeter and an 2 tumor model phantoms with a spherical shape were produced using a 3D printer with a polylactic acid after its 3D images were created using Autodesk software. 3D printed tumor phantoms and EBT3 films were irradiated to compare with treatment plan. After irradiation, vials for calibration and tumor model phantoms were scanned at 9.4T MRI. The spin-spin relaxation times (T_2) according to the each dose were calculated to evaluate the dose response. Acquired images were analyzed using an ImageJ. Scanned MRI images of tumor models were transferred treatment planning system and these were registered to the CT images. In all treatment plans, two arc plans (CW and CCW) were designed to deliver 50 Gy for 10 fractions. For first PTV, treatment plan was accurately designed that 95% of dose to cover 100% of PTV. But 2nd PTV was not intentionally cover 100% of PTV to evaluate the intensity of delivered tumor phantom with polymer gel. We compared the 3D dose distributions obtained from measurements with the 3D printed phantom and calculated with the TPS. Results: 3D printed phantom with a polymer gel was successfully produced. The dose distributions showed qualitatively good agreement among gel, film, and RTP data. Conclusion: A hybrid phantom represents a useful to validate the 3D dose distributions for patient-specific QA.

SU-F-T-580: New Tumor Modeling Using 3D Gel Dosimeter for Brain Stereoctactic Radiotherpy (SRT)

Energy Technology Data Exchange (ETDEWEB)

Chang, K; Kim, M; Kwak, J; Kim, S; Ji, Y; Cho, B; Yoon, S; Lee, S [Asan Medical Center, Seoul, Seoul (Korea, Republic of)

2016-06-15

Purpose: The purpose of this study is to develop new tumor model using 3D printing with 3D dosimeter for brain stereoctactic radiotherpy (SRT). Methods: BANG{sup 3} polymer gel was prepared and the gel-filled glass vials were irradiated with a 6 MV photon beam to acquire the calibration curve that present the change of R2 (1/T{sub 2}) value with dose. Graded doses from 0 to 12 Gy with an interval of 2 Gy were delivered. A kit for calibration of gel dosimeter and an 2 tumor model phantoms with a spherical shape were produced using a 3D printer with a polylactic acid after its 3D images were created using Autodesk software. 3D printed tumor phantoms and EBT3 films were irradiated to compare with treatment plan. After irradiation, vials for calibration and tumor model phantoms were scanned at 9.4T MRI. The spin-spin relaxation times (T{sub 2}) according to the each dose were calculated to evaluate the dose response. Acquired images were analyzed using an ImageJ. Scanned MRI images of tumor models were transferred treatment planning system and these were registered to the CT images. In all treatment plans, two arc plans (CW and CCW) were designed to deliver 50 Gy for 10 fractions. For first PTV, treatment plan was accurately designed that 95% of dose to cover 100% of PTV. But 2nd PTV was not intentionally cover 100% of PTV to evaluate the intensity of delivered tumor phantom with polymer gel. We compared the 3D dose distributions obtained from measurements with the 3D printed phantom and calculated with the TPS. Results: 3D printed phantom with a polymer gel was successfully produced. The dose distributions showed qualitatively good agreement among gel, film, and RTP data. Conclusion: A hybrid phantom represents a useful to validate the 3D dose distributions for patient-specific QA.

Warnings to Counter Choice Blindness for Identification Decisions: Warnings Offer an Advantage in Time but Not in Rate of Detection

Directory of Open Access Journals (Sweden)

Anna Sagana

2018-06-01

Full Text Available Choice blindness for identification decisions refers to the inability of eyewitnesses to detect that an originally recognized target was swapped for a non-identified lineup member. The robustness of the effect calls for measures that can prevent or reduce the negative consequences of choice blindness manipulations. Here, we investigated whether pre- and post-warnings given to participants about the possibility of mistakes reduces choice blindness for identification decisions. Participants (N = 119 were presented with identifications they never made and were asked to justify those decisions. Either before or after the presentation of the manipulated identification outcome, participants were or were not warned about the possibility of mistakes in the identification process. Although warnings were not sufficient to reduce choice blindness for identification decisions they provided a time-related detection advantage. Pre-warned participants questioned the legitimacy of the manipulated outcome sooner (i.e., concurrent detection than participants in other conditions. Hence, pre-warnings can help detect mistakes in the identification procedure at an earlier stage, before they contaminate the memory of the witness and other pieces of evidence. From a theoretical stance, our findings attest to the strength of self-suggestion and indicate that choice blindness effects are deeply rooted in cognition.

The influence of socio-economic characteristics, land use and travel time considerations on mode choice for medium- and longer-distance trips

OpenAIRE

Limtanakool, N.; Dijst, M.J.; Schwanen, T.

2006-01-01

This paper contributes to the limited number of investigations into the influence of the spatial configuration of land use and transport systems on mode choice for medium- and longer-distance travel (defined here as home-based trips of 50 km and over) in the Netherlands. We have employed data from the 1998 Netherlands National Travel Survey to address the question as to how socioeconomic factors, land use attributes, and travel time affect mode choice for medium- and longer-distance travel, a...

Context-dependent preferences in starlings: linking ecology, foraging and choice.

Science.gov (United States)

Vasconcelos, Marco; Monteiro, Tiago; Kacelnik, Alex

2013-01-01

Foraging animals typically encounter opportunities that they either pursue or skip, but occasionally meet several alternatives simultaneously. Behavioural ecologists predict preferences using absolute properties of each option, while decision theorists focus on relative evaluations at the time of choice. We use European starlings (Sturnus vulgaris) to integrate ecological reasoning with decision models, linking and testing hypotheses for value acquisition and choice mechanism. We hypothesise that options' values depend jointly on absolute attributes, learning context, and subject's state. In simultaneous choices, preference could result either from comparing subjective values using deliberation time, or from processing each alternative independently, without relative comparisons. The combination of the value acquisition hypothesis and independent processing at choice time has been called the Sequential Choice Model. We test this model with options equated in absolute properties to exclude the possibility of preference being built at the time of choice. Starlings learned to obtain food by responding to four stimuli in two contexts. In context [AB], they encountered options A5 or B10 in random alternation; in context [CD], they met C10 or D20. Delay to food is denoted, in seconds, by the suffixes. Observed latency to respond (Li) to each option alone (our measure of value) ranked thus: LA≈LCchoice tests to predict sign and strength of preference in pairings. Starlings preferred A5 over C10 and C10 over B10. There was no detectable evaluation time, and preference magnitude was predictable from latency differentials. This implies that value reflects learning rather than choice context, that preferences are not constructed by relative judgements at the time of choice, and that mechanisms adapted for sequential decisions are effective to predict choice behaviour.

Air Cargo Transportation Route Choice Analysis

Science.gov (United States)

Obashi, Hiroshi; Kim, Tae-Seung; Oum, Tae Hoon

2003-01-01

Using a unique feature of air cargo transshipment data in the Northeast Asian region, this paper identifies the critical factors that determine the transshipment route choice. Taking advantage of the variations in the transport characteristics in each origin-destination airports pair, the paper uses a discrete choice model to describe the transshipping route choice decision made by an agent (i.e., freight forwarder, consolidator, and large shipper). The analysis incorporates two major factors, monetary cost (such as line-haul cost and landing fee) and time cost (i.e., aircraft turnaround time, including loading and unloading time, custom clearance time, and expected scheduled delay), along with other controls. The estimation method considers the presence of unobserved attributes, and corrects for resulting endogeneity by use of appropriate instrumental variables. Estimation results find that transshipment volumes are more sensitive to time cost, and that the reduction in aircraft turnaround time by 1 hour would be worth the increase in airport charges by more than $1000. Simulation exercises measures the impacts of alternative policy scenarios for a Korean airport, which has recently declared their intention to be a future regional hub in the Northeast Asian region. The results suggest that reducing aircraft turnaround time at the airport be an effective strategy, rather than subsidizing to reduce airport charges.

The Effects of Repeated Testing, Simulated Malingering, and Traumatic Brain Injury on Visual Choice Reaction Time

Directory of Open Access Journals (Sweden)

David L Woods

2015-11-01

Full Text Available Choice reaction time (CRT, the time required to discriminate and respond appropriately to different stimuli, is a basic measure of attention and processing speed. Here, we describe the reliability and clinical sensitivity of a new CRT test that presents lateralized visual stimuli and adaptively adjusts stimulus onset asynchronies (SOAs using a staircase procedure. Experiment 1 investigated the test-retest reliability in three test sessions at weekly intervals. Performance in the first test session was accurately predicted from age and computer-use regression functions obtained in a previously studied normative cohort. Central processing time (CentPT, the difference between the CRTs and simple reaction time latencies measured in a separate experiment, accounted for 55% of CRT latency and more than 50% of CRT latency variance. Performance improved significantly across the three test sessions. High intraclass correlation coefficients (ICCs were seen for CRTs (0.90, CentPTs (0.87, and an omnibus performance measure (0.81 that combined CRT and minimal SOA (mSOA z-scores. Experiment 2 investigated performance in the same participants when instructed to feign symptoms of traumatic brain injury (TBI: 87% produced abnormal omnibus z-scores. Simulated malingerers showed greater elevations in simple than choice reaction times, and hence reduced CentPTs. Latency-consistency z-scores, based on the difference between the CRTs obtained and those predicted from CentPT latencies, discriminated malingering participants from controls with high sensitivity and specificity. Experiment 3 investigated CRT test performance in military veterans who had suffered combat-related TBI and symptoms of post-traumatic stress disorder and revealed small but significant deficits in performance. The results indicate that the new CRT test shows high test-retest reliability, can assist in detecting participants performing with suboptimal effort, and is sensitive to the effects of

Measuring strategic control in implicit learning: how and why?

Science.gov (United States)

Norman, Elisabeth

2015-01-01

Several methods have been developed for measuring the extent to which implicitly learned knowledge can be applied in a strategic, flexible manner. Examples include generation exclusion tasks in Serial Reaction Time (SRT) learning (Goschke, 1998; Destrebecqz and Cleeremans, 2001) and 2-grammar classification tasks in Artificial Grammar Learning (AGL; Dienes et al., 1995; Norman et al., 2011). Strategic control has traditionally been used as a criterion for determining whether acquired knowledge is conscious or unconscious, or which properties of knowledge are consciously available. In this paper I first summarize existing methods that have been developed for measuring strategic control in the SRT and AGL tasks. I then address some methodological and theoretical questions. Methodological questions concern choice of task, whether the measurement reflects inhibitory control or task switching, and whether or not strategic control should be measured on a trial-by-trial basis. Theoretical questions concern the rationale for including measurement of strategic control, what form of knowledge is strategically controlled, and how strategic control can be combined with subjective awareness measures.

Factors influencing junior doctors' choices of future specialty: trends over time and demographics based on results from UK national surveys.

Science.gov (United States)

Smith, Fay; Lambert, Trevor W; Goldacre, Michael J

2015-10-01

To study trends in factors influencing junior doctors' choice of future specialty. Respondents were asked whether each of 15 factors had a great deal of influence on their career choice, a little influence or no influence on it. Percentages are reported of those who specified that a factor had a great deal of influence on their career choice. UK. A total of 15,765 UK-trained doctors who graduated between 1999 and 2012. Questions about career choices and factors which may have influenced those choices, in particular comparing doctors who qualified in 2008-2012 with those who qualified in 1999-2002. Enthusiasm for and commitment to the specialty was a greater influence on career choice in the 2008-2012 qualifiers (81%) than those of 1999-2002 (64%), as was consideration of their domestic circumstances (43% compared with 20%). Prospects for promotion were less important to recent cohorts (16%) than older cohorts (21%), as were financial prospects (respectively, 10% and 14%). Domestic circumstances and working hours were considered more important, and financial prospects less important, by women than men. Inclination before medical school was rated as important by 41% of doctors who were over 30 years old, compared with 13% of doctors who were under 21, at the time of starting medical school. The increasing importance of both domestic circumstances and enthusiasm for their specialty choice in recent cohorts suggest that today's young doctors prize both work-life balance and personal fulfilment at work more highly than did their predecessors. The differences in motivations of older and younger generations of doctors, men and women, and doctors who start medical school relatively late are worthy of note. © The Royal Society of Medicine.

On synchronous parallel computations with independent probabilistic choice

International Nuclear Information System (INIS)

Reif, J.H.

1984-01-01

This paper introduces probabilistic choice to synchronous parallel machine models; in particular parallel RAMs. The power of probabilistic choice in parallel computations is illustrate by parallelizing some known probabilistic sequential algorithms. The authors characterize the computational complexity of time, space, and processor bounded probabilistic parallel RAMs in terms of the computational complexity of probabilistic sequential RAMs. They show that parallelism uniformly speeds up time bounded probabilistic sequential RAM computations by nearly a quadratic factor. They also show that probabilistic choice can be eliminated from parallel computations by introducing nonuniformity

Motherhood, Choice and the British Media: A Time to Reflect

Science.gov (United States)

Hadfield, L.; Rudoe, N.; Sanderson-Mann, J.

2007-01-01

In this paper we ask: How is motherhood being represented in the British media, especially in relation to choice, age and fertility? Do media discourses reflect a redefinition or transformation of "motherhood" in the twenty-first century, and what implications do they have for feminist research into maternal identity and motherhood? As…

Determinants of choice of delivery place: Testing rational choice theory and habitus theory.

Science.gov (United States)

Broda, Anja; Krüger, Juliane; Schinke, Stephanie; Weber, Andreas

2018-05-07

The current study uses two antipodal social science theories, the rational choice theory and the habitus theory, and applies these to describe how women choose between intraclinical (i.e., hospital-run birth clinics) and extraclinical (i.e., midwife-led birth centres or home births) delivery places. Data were collected in a cross-sectional questionnaire-based survey among 189 women. A list of 22 determinants, conceptualized to capture the two theoretical concepts, were rated on a 7-point Likert scale with 1 = unimportant to 7 = very important. The analytic method was structural equation modelling. A model was built, in which the rational choice theory and the habitus theory as latent variables predicted the choice of delivery place. With regards to the choice of delivery place, 89.3% of the women wanted an intraclinical and 10.7% an extraclinical delivery place at the time of their last child's birth. Significant differences between women with a choice of an intraclinical or extraclinical delivery place were found for 14 of the 22 determinants. In the structural equation model, rational choice theory determinants predicted a choice of intraclinical delivery and habitus theory determinants predicted a choice of extraclinical delivery. The two theories had diametrically opposed effects on the choice of delivery place. Women are more likely to decide on intraclinical delivery when arguments such as high medical standards, positive evaluations, or good advanced information are rated important. In contrast, women are more likely to decide on extraclinical delivery when factors such as family atmosphere during birth, friendliness of health care professionals, or consideration of the woman's interests are deemed important. A practical implication of our study is that intraclinical deliveries may be promoted by providing comprehensive information, data and facts on various delivery-related issues, while extraclinical deliveries may be fostered by healthcare

Assessment of pedophilic sexual interest with an attentional choice reaction time task.

Science.gov (United States)

Mokros, Andreas; Dombert, Beate; Osterheider, Michael; Zappalà, Angelo; Santtila, Pekka

2010-10-01

Choice-reaction time (CRT) is an experimental information-processing paradigm. Based on an interference effect in visual attention, the CRT method has been shown to be suitable for measuring sexual orientation in men and women. The present study assessed the potential of the CRT to identify deviant (i.e., pedophilic) sexual interest. Participants were patients from forensic-psychiatric hospitals: 21 child molesters and 21 non-sex offenders. The dependent variable was reaction time in an ostensible seek-and-locate task (i.e., identifying the position of a dot superimposed on a picture of a person). There was an interaction effect between stimulus age category and participant group status: Child molesters took longer to respond to pictures of children relative to pictures of adults. Non-sex offenders showed an opposite pattern (i.e., longer reaction times with pictures of adults than with pictures of children). In addition, the data supported the notion of sexual content induced delay: Subjects took longer for the task with nude stimuli than with clothed ones. A subtractive preference index, derived from the reaction times for child and adult stimulus material, allowed distinguishing participants from both groups almost perfectly (ROC-AUC = .998). We conclude that a match of sexual interest with properties of visual stimuli led to a cognitive interference effect: Attentional resources were drawn from the ostensible task of locating the dot towards exploring the picture. This opens up the possibility of using this interference effect (i.e., the delay of response times) for diagnostic purposes.

Traffic-light labels and choice architecture: promoting healthy food choices.

Science.gov (United States)

Thorndike, Anne N; Riis, Jason; Sonnenberg, Lillian M; Levy, Douglas E

2014-02-01

Preventing obesity requires maintenance of healthy eating behaviors over time. Food labels and strategies that increase visibility and convenience of healthy foods (choice architecture) promote healthier choices, but long-term effectiveness is unknown. Assess effectiveness of traffic-light labeling and choice architecture cafeteria intervention over 24 months. Longitudinal pre-post cohort follow-up study between December 2009 and February 2012. Data were analyzed in 2012. Large hospital cafeteria with a mean of 6511 transactions daily. Cafeteria sales were analyzed for (1) all cafeteria customers and (2) a longitudinal cohort of 2285 hospital employees who used the cafeteria regularly. After a 3-month baseline period, cafeteria items were labeled green (healthy); yellow (less healthy); or red (unhealthy) and rearranged to make healthy items more accessible. Proportion of cafeteria sales that were green or red during each 3-month period from baseline to 24 months. Changes in 12- and 24-month sales were compared to baseline for all transactions and transactions by the employee cohort. The proportion of sales of red items decreased from 24% at baseline to 20% at 24 months (pchoice architecture cafeteria intervention resulted in sustained healthier choices over 2 years, suggesting that food environment interventions can promote long-term changes in population eating behaviors. © 2013 American Journal of Preventive Medicine Published by American Journal of Preventive Medicine All rights reserved.

Examination about the effects of future career choice on time perspective in Japanese high school students.

Science.gov (United States)

Tsuzuki, Manabu

2015-03-30

This study investigated types of career choice in high school students and examined the effects of career paths on time perspective development. The participants were 4,756 third grade students from nine public high schools in Tokyo. The high school questionnaire survey was conducted throughout autumn of 2008, 2009, and 2010. One year later, 962 graduates participated in the follow-up questionnaire survey by post. Distinguishing gender difference among career paths was found. Girls tend to choose significantly shorter learning careers (p time perspective than other groups (p time perspective between "school to school transition" and "school to work transition". It is suggested that the "school to work transition" tends to be more critical for adolescents and has negative effects on time perspective. These results suggest that the goal content in careers may promote or inhibit the formation of time perspectives during the graduation transition.

Kinetics of aggregation with choice.

Science.gov (United States)

Ben-Naim, E; Krapivsky, P L

2016-12-01

We generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected and the target cluster merges with the larger of the two candidate clusters. We study the long-time asymptotic behavior and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of different features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tails of the density are overpopulated, at the expense of the density of moderate-size clusters. We also study the complementary case where the smaller candidate cluster participates in the aggregation process and find an abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters and a symmetric implementation where the choice is between two pairs of clusters.

Response competition and response inhibition during different choice-discrimination tasks: evidence from ERP measured inside MRI scanner.

Science.gov (United States)

Gonzalez-Rosa, Javier J; Inuggi, Alberto; Blasi, Valeria; Cursi, Marco; Annovazzi, Pietro; Comi, Giancarlo; Falini, Andrea; Leocani, Letizia

2013-07-01

We investigated the neural correlates underlying response inhibition and conflict detection processes using ERPs and source localization analyses simultaneously acquired during fMRI scanning. ERPs were elicited by a simple reaction time task (SRT), a Go/NoGo task, and a Stroop-like task (CST). The cognitive conflict was thus manipulated in order to probe the degree to which information processing is shared across cognitive systems. We proposed to dissociate inhibition and interference conflict effects on brain activity by using identical Stroop-like congruent/incongruent stimuli in all three task contexts and while varying the response required. NoGo-incongruent trials showed a larger N2 and enhanced activations of rostral anterior cingulate cortex (ACC) and pre-supplementary motor area, whereas Go-congruent trials showed a larger P3 and increased parietal activations. Congruent and incongruent conditions of the CST task also elicited similar N2, P3 and late negativity (LN) ERPs, though CST-incongruent trials revealed a larger LN and enhanced prefrontal and ACC activations. Considering the stimulus probability and experimental manipulation of our study, current findings suggest that NoGo N2 and frontal NoGo P3 appear to be more associated to response inhibition rather than a specific conflict monitoring, whereas occipito-parietal P3 of Go and CST conditions may be more linked to a planned response competition between the prepared and required response. LN, however, appears to be related to higher level conflict monitoring associated with response choice-discrimination but not when the presence of cognitive conflict is associated with response inhibition. Copyright © 2013. Published by Elsevier B.V.

The impact of choice context on consumers' choice heuristics

DEFF Research Database (Denmark)

Mueller Loose, Simone; Scholderer, Joachim; Corsi, Armando M.

2012-01-01

Context effects in choice settings have received recent attention but little is known about the impact of context on choice consistency and the extent to which consumers apply choice heuristics. The sequence of alternatives in a choice set is examined here as one specific context effect. We compare...... how a change from a typical price order to a sensory order in wine menus affects consumer choice. We use pre-specified latent heuristic classes to analyse the existence of different choice processes, which begins to untangle the ‘black box’ of how consumers choose. Our findings indicate...... that in the absence of price order, consumers are less price-sensitive, pay more attention to visually salient cues, are less consistent in their choices and employ other simple choice heuristics more frequently than price. Implications for consumer research, marketing and consumer policy are discussed....

'Sea legs': sharpened Romberg test after three days on a live-aboard dive boat.

Science.gov (United States)

Gibbs, Clinton R; Commons, Katherine H; Brown, Lawrence H; Blake, Denise F

2010-12-01

The sharpened Romberg test (SRT) is commonly used by diving and hyperbaric physicians as an indicator of neurological decompression illness (DCI). People who spend a prolonged time on a boat at sea experience impairment in their balance on returning to shore, a condition known as mal de debarquement ('sea legs'). This conditioning of the vestibular system to the rocking motion of a boat at sea may impact on the utility of the SRT in assessing a diver with potential DCI after a live-aboard dive trip. To assess the impact 'sea legs' has on the SRT after three days on a live-aboard dive trip. Thirty-nine staff and passengers of a three-day, live-aboard dive trip performed a SRT before and after their journey, with assessment of potential variables, including middle ear barotrauma, alcohol consumption, sea-sickness and occult DCI. There was no statistically significant impact on SRT performance, with 100% completion pre-trip and 35 out of 36 divers (97.2%) post-trip. There were trends towards more attempts being required and time needed for successful SRT post-trip, but these were not statistically significant. There was a small, but noteworthy incidence of middle-ear barotrauma, with seven people affected pre-trip, and 13 post-trip. There was a higher incidence in student divers. Middle-ear barotrauma did not appear to have a direct impact on SRT performance. There was no significant impact on SRT performance resulting from 'sea legs' after three days at sea. Recreational divers, especially dive students, have a substantial incidence of mild middle ear barotrauma.

Make Better Food Choices

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10 tips Nutrition Education Series make better food choices 10 tips for women’s health Fruits Grains Dairy Vegetables Protein Make yourself a priority and take time to care for yourself. ChooseMyPlate. gov ...

Dynamic Portfolio Choice with Frictions

DEFF Research Database (Denmark)

Garleanu, Nicolae; Heje Pedersen, Lasse

2016-01-01

We show how portfolio choice can be modeled in continuous time with transitory and persistent transaction costs, multiple assets, multiple signals predicting returns, and general signal dynamics. The objective function is derived from the limit of discrete-time models with endogenous transaction...

Concurrent variable-interval variable-ratio schedules in a dynamic choice environment.

Science.gov (United States)

Bell, Matthew C; Baum, William M

2017-11-01

Most studies of operant choice have focused on presenting subjects with a fixed pair of schedules across many experimental sessions. Using these methods, studies of concurrent variable- interval variable-ratio schedules helped to evaluate theories of choice. More recently, a growing literature has focused on dynamic choice behavior. Those dynamic choice studies have analyzed behavior on a number of different time scales using concurrent variable-interval schedules. Following the dynamic choice approach, the present experiment examined performance on concurrent variable-interval variable-ratio schedules in a rapidly changing environment. Our objectives were to compare performance on concurrent variable-interval variable-ratio schedules with extant data on concurrent variable-interval variable-interval schedules using a dynamic choice procedure and to extend earlier work on concurrent variable-interval variable-ratio schedules. We analyzed performances at different time scales, finding strong similarities between concurrent variable-interval variable-interval and concurrent variable-interval variable- ratio performance within dynamic choice procedures. Time-based measures revealed almost identical performance in the two procedures compared with response-based measures, supporting the view that choice is best understood as time allocation. Performance at the smaller time scale of visits accorded with the tendency seen in earlier research toward developing a pattern of strong preference for and long visits to the richer alternative paired with brief "samples" at the leaner alternative ("fix and sample"). © 2017 Society for the Experimental Analysis of Behavior.

Exclusive queueing model including the choice of service windows

Science.gov (United States)

Tanaka, Masahiro; Yanagisawa, Daichi; Nishinari, Katsuhiro

2018-01-01

In a queueing system involving multiple service windows, choice behavior is a significant concern. This paper incorporates the choice of service windows into a queueing model with a floor represented by discrete cells. We contrived a logit-based choice algorithm for agents considering the numbers of agents and the distances to all service windows. Simulations were conducted with various parameters of agent choice preference for these two elements and for different floor configurations, including the floor length and the number of service windows. We investigated the model from the viewpoint of transit times and entrance block rates. The influences of the parameters on these factors were surveyed in detail and we determined that there are optimum floor lengths that minimize the transit times. In addition, we observed that the transit times were determined almost entirely by the entrance block rates. The results of the presented model are relevant to understanding queueing systems including the choice of service windows and can be employed to optimize facility design and floor management.

A simple test of choice stepping reaction time for assessing fall risk in people with multiple sclerosis.

Science.gov (United States)

Tijsma, Mylou; Vister, Eva; Hoang, Phu; Lord, Stephen R

2017-03-01

Purpose To determine (a) the discriminant validity for established fall risk factors and (b) the predictive validity for falls of a simple test of choice stepping reaction time (CSRT) in people with multiple sclerosis (MS). Method People with MS (n = 210, 21-74y) performed the CSRT, sensorimotor, balance and neuropsychological tests in a single session. They were then followed up for falls using monthly fall diaries for 6 months. Results The CSRT test had excellent discriminant validity with respect to established fall risk factors. Frequent fallers (≥3 falls) performed significantly worse in the CSRT test than non-frequent fallers (0-2 falls). With the odds of suffering frequent falls increasing 69% with each SD increase in CSRT (OR = 1.69, 95% CI: 1.27-2.26, p = falls in people with MS. This test may prove useful in documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions. Implications for rehabilitation Good choice stepping reaction time (CSRT) is required for maintaining balance. A simple low-tech CSRT test has excellent discriminative and predictive validity in relation to falls in people with MS. This test may prove useful documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions.

Selective attention increases choice certainty in human decision making.

Science.gov (United States)

Zizlsperger, Leopold; Sauvigny, Thomas; Haarmeier, Thomas

2012-01-01

Choice certainty is a probabilistic estimate of past performance and expected outcome. In perceptual decisions the degree of confidence correlates closely with choice accuracy and reaction times, suggesting an intimate relationship to objective performance. Here we show that spatial and feature-based attention increase human subjects' certainty more than accuracy in visual motion discrimination tasks. Our findings demonstrate for the first time a dissociation of choice accuracy and certainty with a significantly stronger influence of voluntary top-down attention on subjective performance measures than on objective performance. These results reveal a so far unknown mechanism of the selection process implemented by attention and suggest a unique biological valence of choice certainty beyond a faithful reflection of the decision process.

Initial clinical results of linac-based stereotactic radiosurgery and stereotactic radiotherapy for pituitary adenomas

International Nuclear Information System (INIS)

Mitsumori, Michihide; Shrieve, Dennis C.; Alexander, Eben; Kaiser, Ursula B.; Richardson, Gary E.; Black, Peter McL.; Loeffler, Jay S.

1998-01-01

Purpose: To retrospectively evaluate the initial clinical results of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) for pituitary adenomas with regard to tumor and hormonal control and adverse effects of the treatment. Subjects and Methods: Forty-eight patients with pituitary adenoma who underwent SRS or SRT between September 1989 and September 1995 were analyzed. Of these, 18 received SRS and 30 received SRT. The median tumor volumes were 1.9 cm 3 for SRS and 5.7 cm 3 for SRT. Eleven of the SRS and 18 of the SRT patients were hormonally active at the time of the initial diagnosis. Four of the SRS and none of the SRT patients had a history of prior radiation therapy. Both SRS and SRT were performed using a dedicated stereotactic 6-MV linear accelerator (LINAC). The dose and normalization used for the SRS varied from 1000 cGy at 85% of the isodose line to 1500 cGy at 65% of the isodose line. For SRT patients, a total dose of 4500 cGy at 90% or 95% of the isodose line was delivered in 25 fractions of 180 cGy daily doses. Results: Disease control--The three year tumor control rate was 91.1% (100% for SRS and 85.3% for SRT). Normalization of the hormonal abnormality was achieved in 47% of the 48 patients (33% for SRS and 54% for SRT). The average time required for normalization was 8.5 months for SRS and 18 months for SRT. Adverse effects--The 3-year rate of freedom from central nervous system adverse effects was 89.7% (72.2% for SRS and 100% for SRT). Three patients who received SRS for a tumor in the cavernous sinus developed a ring enhancement in the temporal lobe as shown by follow-up magnetic resonance imaging. Two of these cases were irreversible and were considered to be radiation necrosis. None of the 48 patients developed new neurocognitive or visual disorders attributable to the irradiation. The incidence of endocrinological adverse effects were similar in the two groups, resulting in 3-year rates of freedom from newly

Investing in biogas: Timing, technological choice and the value of flexibility from input mix

International Nuclear Information System (INIS)

Di Corato, Luca; Moretto, Michele

2011-01-01

In a stochastic dynamic frame, we study the technology choice problem of a continuous co-digestion biogas plant where input factors are substitutes but need to be mixed together to provide output. Given any initial rule for the composition of the feedstock, we consider the possibility of revising it if economic circumstances make it profitable. Flexibility in the mix is an advantage under randomly fluctuating input costs and comes at a higher investment cost. We show that the degree of flexibility in the productive technology installed depends on the value of the option to profitably re-arrange the input mix. Such option adds value to the project in that it provides a device for hedging against fluctuations in the input relative convenience. Accounting for such value we discuss the trade-off between investment timing and profit smoothing flexibility. - Research highlights: ► We study the technology choice problem of a continuous co-digestion biogas plant where input factors are substitutes but need to be mixed together to provide output. ► We show that the degree of flexibility in the productive technology installed depends on the value of the option to profitably re-arrange the input mix. ► Such option adds value to the project in that it provides a device for hedging against fluctuations in the input relative convenience.

Traffic-Light Labels and Choice Architecture Promoting Healthy Food Choices

Science.gov (United States)

Thorndike, Anne N.; Riis, Jason; Sonnenberg, Lillian M.; Levy, Douglas E.

2014-01-01

Background Preventing obesity requires maintenance of healthy eating behaviors over time. Food labels and strategies that increase visibility and convenience of healthy foods (choice architecture) promote healthier choices, but long-term effectiveness is unknown. Purpose Assess effectiveness of traffic-light labeling and choice architecture cafeteria intervention over 24 months. Design Longitudinal pre–post cohort follow-up study between December 2009 and February 2012. Data were analyzed in 2012. Setting/participants Large hospital cafeteria with mean of 6511 transactions daily. Cafeteria sales were analyzed for: (1) all cafeteria customers and (2) longitudinal cohort of 2285 hospital employees who used the cafeteria regularly. Intervention After 3-month baseline period, cafeteria items were labeled green (healthy), yellow (less healthy) or red (unhealthy) and rearranged to make healthy items more accessible. Main outcome measures Proportion of cafeteria sales that were green or red during each 3-month period from baseline to 24 months. Changes in 12- and 24-month sales were compared to baseline for all transactions and transactions by the employee cohort. Results The proportion of sales of red items decreased from 24% at baseline to 20% at 24 months (p<0.001), and green sales increased from 41% to 46% (p<0.001). Red beverages decreased from 26% of beverage sales at baseline to 17% at 24 months (p<0.001); green beverages increased from 52% to 60% (p<0.001). Similar patterns were observed for the cohort of employees, with largest change for red beverages (23% to 14%, p<0.001). Conclusions A traffic-light and choice architecture cafeteria intervention resulted in sustained healthier choices over 2 years, suggesting food environment interventions can promote long-term changes in population eating behaviors. PMID:24439347

Choice with frequently changing food rates and food ratios.

Science.gov (United States)

Baum, William M; Davison, Michael

2014-03-01

In studies of operant choice, when one schedule of a concurrent pair is varied while the other is held constant, the constancy of the constant schedule may exert discriminative control over performance. In our earlier experiments, schedules varied reciprocally across components within sessions, so that while food ratio varied food rate remained constant. In the present experiment, we held one variable-interval (VI) schedule constant while varying the concurrent VI schedule within sessions. We studied five conditions, each with a different constant left VI schedule. On the right key, seven different VI schedules were presented in seven different unsignaled components. We analyzed performances at several different time scales. At the longest time scale, across conditions, behavior ratios varied with food ratios as would be expected from the generalized matching law. At shorter time scales, effects due to holding the left VI constant became more and more apparent, the shorter the time scale. In choice relations across components, preference for the left key leveled off as the right key became leaner. Interfood choice approximated strict matching for the varied right key, whereas interfood choice hardly varied at all for the constant left key. At the shortest time scale, visit patterns differed for the left and right keys. Much evidence indicated the development of a fix-and-sample pattern. In sum, the procedural difference made a large difference to performance, except for choice at the longest time scale and the fix-and-sample pattern at the shortest time scale. © Society for the Experimental Analysis of Behavior.

Repetition priming of face recognition in a serial choice reaction-time task.

Science.gov (United States)

Roberts, T; Bruce, V

1989-05-01

Marshall & Walker (1987) found that pictorial stimuli yield visual priming that is disrupted by an unpredictable visual event in the response-stimulus interval. They argue that visual stimuli are represented in memory in the form of distinct visual and object codes. Bruce & Young (1986) propose similar pictorial, structural and semantic codes which mediate the recognition of faces, yet repetition priming results obtained with faces as stimuli (Bruce & Valentine, 1985), and with objects (Warren & Morton, 1982) are quite different from those of Marshall & Walker (1987), in the sense that recognition is facilitated by pictures presented 20 minutes earlier. The experiment reported here used different views of familiar and unfamiliar faces as stimuli in a serial choice reaction-time task and found that, with identical pictures, repetition priming survives and intervening item requiring a response, with both familiar and unfamiliar faces. Furthermore, with familiar faces such priming was present even when the view of the prime was different from the target. The theoretical implications of these results are discussed.

Speakers' choice of frame in binary choice

Directory of Open Access Journals (Sweden)

Marc van Buiten

2009-02-01

Full Text Available A distinction is proposed between extit{recommending for} preferred choice options and extit{recommending against} non-preferred choice options. In binary choice, both recommendation modes are logically, though not psychologically, equivalent. We report empirical evidence showing that speakers recommending for preferred options predominantly select positive frames, which are less common when speakers recommend against non-preferred options. In addition, option attractiveness is shown to affect speakers' choice of frame, and adoption of recommendation mode. The results are interpreted in terms of three compatibility effects, (i extit{recommendation mode---valence framing compatibility}: speakers' preference for positive framing is enhanced under extit{recommending for} and diminished under extit{recommending against} instructions, (ii extit{option attractiveness---valence framing compatibility}: speakers' preference for positive framing is more pronounced for attractive than for unattractive options, and (iii extit{recommendation mode---option attractiveness compatibility}: speakers are more likely to adopt a extit{recommending for} approach for attractive than for unattractive binary choice pairs.

How passion and impulsivity influence a player's choice of videogame, intensity of playing and time spent playing

OpenAIRE

Puerta-Cortés, Diana Ximena; Panova, Tayana; Carbonell, Xavier; Chamarro, Andrés

2016-01-01

Videogames have received much attention in addiction research due to their popularity and frequent use. However, few studies have addressed the effect of passion and impulsivity in gamers. Therefore, the aim of the current study was to examine the influence of passion and impulsivity on the intensity of play, playing time, and choice of Massive Multiplayer Online Role Play Game (MMORPG) vs. non-MMORPG. A sample of 630 university students (40.7% Colombian, 59.3% Spanish) responded ...

The uncertain first-time voter: Effects of political media exposure on young citizens’ formation of vote choice in a digital media environment

DEFF Research Database (Denmark)

Ohme, Jakob; de Vreese, Claes Holger; Albæk, Erik

2018-01-01

The digital media environment changes the way citizens receive political information, also during an election campaign. Particularly first-time voters increasingly use social media platforms as news sources. Yet, it is less clear how accessing political information in such a unique social setting...... exposure and certainty can be mediated by active campaign participation. An 11-wave national panel study was conducted, using a smartphone-based assessment of citizens’ (n = 1108) media exposure and vote choice certainty across the campaign period. Results suggest that first-time voters’ social media...... affects these cohorts’ decision-making processes during an election campaign, compared to experienced voters. We compare effects of these two groups’ political information exposure on their vote choice certainty during the 2015 Danish national election. We furthermore test how the relation between...

Simulation of Cavity Flow by the Lattice Boltzmann Method using Multiple-Relaxation-Time scheme

International Nuclear Information System (INIS)

Ryu, Seung Yeob; Kang, Ha Nok; Seo, Jae Kwang; Yun, Ju Hyeon; Zee, Sung Quun

2006-01-01

Recently, the lattice Boltzmann method(LBM) has gained much attention for its ability to simulate fluid flows, and for its potential advantages over conventional CFD method. The key advantages of LBM are, (1) suitability for parallel computations, (2) absence of the need to solve the time-consuming Poisson equation for pressure, and (3) ease with multiphase flows, complex geometries and interfacial dynamics may be treated. The LBM using relaxation technique was introduced by Higuerea and Jimenez to overcome some drawbacks of lattice gas automata(LGA) such as large statistical noise, limited range of physical parameters, non- Galilean invariance, and implementation difficulty in three-dimensional problem. The simplest LBM is the lattice Bhatnager-Gross-Krook(LBGK) equation, which based on a single-relaxation-time(SRT) approximation. Due to its extreme simplicity, the lattice BGK(LBGK) equation has become the most popular lattice Boltzmann model in spite of its well-known deficiencies, for example, in simulating high-Reynolds numbers flow. The Multiple-Relaxation-Time(MRT) LBM was originally developed by D'Humieres. Lallemand and Luo suggests that the use of a Multiple-Relaxation-Time(MRT) models are much more stable than LBGK, because the different relaxation times can be individually tuned to achieve 'optimal' stability. A lid-driven cavity flow is selected as the test problem because it has geometrically singular points in the flow, but geometrically simple. Results are compared with those using SRT, MRT model in the LBGK method and previous simulation data using Navier-Stokes equations for the same flow conditions. In summary, LBM using MRT model introduces much less spatial oscillations near geometrical singular points, which is important for the successful simulation of higher Reynolds number flows

Neuro-economics in chicks: foraging choices based on amount, delay and cost.

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Matsushima, Toshiya; Kawamori, Ai; Bem-Sojka, Tiaza

2008-06-15

Studies on the foraging choices are reviewed, with an emphasis on the neural representations of elementary factors of food (i.e., amount, delay and consumption time) in the avian brain. Domestic chicks serve as an ideal animal model in this respect, as they quickly associate cue colors with subsequently supplied food rewards, and their choices are quantitatively linked with the rewards. When a pair of such color cues was simultaneously presented, the trained chicks reliably made choices according to the profitability of food associated with each color. Two forebrain regions are involved in distinct aspects of choices; i.e., nucleus accumbens-medial striatum (Ac-MSt) and arcopallium intermedium (AI), an association area in the lateral forebrain. Localized lesions of Ac-MSt enhanced delay aversion, and the ablated chicks made impulsive choices of immediate reward more frequently than sham controls. On the other hand, lesions of AI enhanced consumption-time aversion, and the ablated chicks shifted their choices toward easily consumable reward with their impulsiveness unchanged; delay and consumption time are thus doubly dissociated. Furthermore, chicks showed distinct patterns of risk-sensitive choices depending on the factor that varied at trials. Risk aversion occurred when food amount varied, whereas consistent risk sensitivity was not found when the delay varied; amount and delay were not interchangeable. Choices are thus deviated from those predicted as optima. Instead, factors such as amount, delay and consumption time could be separately represented and processed to yield economically sub-optimal choices.

Socialized choices: Labour market behaviour of Dutch mothers

NARCIS (Netherlands)

Ruitenberg, J.F.

2014-01-01

Dutch mothers display diverse labour market behaviour, though typically they work part-time, making modest use of childcare. It is generally assumed that Dutch women are free to make their own choices regarding employment. This narrative of 'choice' finds fertile ground in an era of general

Physiological and cognitive mediators for the association between self-reported depressed mood and impaired choice stepping reaction time in older people.

NARCIS (Netherlands)

Kvelde, T.; Pijnappels, M.A.G.M.; Delbaere, K.; Close, J.C.; Lord, S.R.

2010-01-01

Background. The aim of the study was to use path analysis to test a theoretical model proposing that the relationship between self-reported depressed mood and choice stepping reaction time (CSRT) is mediated by psychoactive medication use, physiological performance, and cognitive ability.A total of

Timing of union formation and partner choice in immigrant societies: The United States and Germany.

Science.gov (United States)

Soehl, Thomas; Yahirun, Jenjira

2011-12-01

As Gordon noted in his 1964 treatise on assimilation, marriage across ethnic boundaries and in particular, marriage into the mainstream is a key indicator as well as a mechanism of immigrant assimilation. Since then research has investigated numerous micro- and macro level correlates of exogamy. In this paper we focus on a topic that has received less attention thus far - how the timing of marriage is associated with partner choice. We compare the United States and Germany as two countries with significant immigrant and second-generation populations but where mainstream patterns of union formation differ. In both contexts we show that unions that cross ethnic boundaries happen later in life than those that stay within. Comparing across countries we argue that in Germany differences in the timing of union formation between the second generation and the mainstream, may pose additional barriers to intermarriage that do not exist in the United States.

Commitment-based action: Rational choice theory and contrapreferential choice

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Radovanović Bojana

2014-01-01

Full Text Available This paper focuses on Sen’s concept of contrapreferential choice. Sen has developed this concept in order to overcome weaknesses of the rational choice theory. According to rational choice theory a decision-maker can be always seen as someone who maximises utility, and each choice he makes as the one that brings to him the highest level of personal wellbeing. Sen argues that in some situations we chose alternatives that bring us lower level of wellbeing than we could achieve if we had chosen some other alternative available to us. This happens when we base our decisions on moral principles, when we act out of duty. Sen calls such action a commitment-based action. When we act out of commitment we actually neglect our preferences and thus we make a contrapreferential choice, as Sen argues. This paper shows that, contrary to Sen, a commitment-based action can be explained within the framework of rational choice theory. However, when each choice we make can be explained within the framework of rational choice theory, when in everything we do maximisation principle can be loaded, then the variety of our motives and traits is lost, and the explanatory power of the rational choice theory is questionable. [Projekat Ministarstva nauke Republike Srbije, br. 47009: Evropske integracije i društveno-ekonomske promene privrede Srbije na putu ka EU i br. 179015: Izazovi i perspektive strukturnih promena u Srbiji: Strateški pravci ekonomskog razvoja i usklađivanje sa zahtevima EU

Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly.

Science.gov (United States)

Wormhoudt, Tiffany L; Boss, Mary-Keara; Lunn, Katharine; Griffin, Lynn; Leary, Del; Dowers, Kristy; Rao, Sangeeta; LaRue, Susan M

2018-05-21

Conventional fractionated radiotherapy has been shown to be partially effective for management of pituitary tumors in cats that cause acromegaly and diabetes mellitus (DM), but, the efficacy and safety of stereotactic radiation therapy (SRT) as a treatment for acromegalic cats has not been described. Stereotactic radiation therapy is an effective and safe treatment for controlling acromegaly associated with pituitary adenomas in cats. Additionally, SRT-treated acromegalic cats with DM will experience a decrease in insulin requirements after radiation therapy. Fifty-three client-owned cats referred to Colorado State University for SRT to treat pituitary tumors causing poorly controlled DM secondary to acromegaly. Retrospective study of cats treated for acromegaly with SRT between 2008 and 2016 at Colorado State University. Diagnosis of acromegaly was based on history, physical examination, laboratory results, and cross-sectional imaging of the pituitary. Signalment, radiation protocol, insulin requirements over time, adverse effects, and survival were recorded. Median survival time was 1072 days. Of the 41 cats for which insulin dosage information was available, 95% (39/41) experienced a decrease in required insulin dose, with 32% (13/41) achieving diabetic remission. Remission was permanent in 62% (8/13) and temporary in 38% (5/13) cats. Median duration to lowest insulin dose was 9.5 months. Of the treated cats, 14% developed hypothyroidism and required supplementation after SRT. Stereotactic radiation therapy is safe and effective for treating cats with acromegaly. Cats treated with SRT have improved survival time and control of their DM when compared to previously reported patients treated with non-SRT. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Students as First-Time Voters: The Role of Voter Advice Applications in Self-Reflection on Party Choice and Political Identity

Science.gov (United States)

Kristensen, Niels Nørgaard; Solhaug, Trond

2017-01-01

Purpose: This article analyses what characterises first time voters' self-reflections on party choice as they use voter advice applications. Method: This study is based on interviews of 28 Norwegian students (age 18-20) preparing themselves for their first election. Findings: Finding a party to vote for is primarily characterized by a process of…

Security. Review Software for Advanced CHOICE. CHOICE (Challenging Options in Career Education).

Science.gov (United States)

Pitts, Ilse M.; And Others

CHOICE Security is an Apple computer game activity designed to help secondary migrant students memorize their social security numbers and reinforce job and role information presented in "Career Notes, First Applications." The learner may choose from four time options and whether to have the social security number visible on the screen or…

Does Correct Answer Distribution Influence Student Choices When Writing Multiple Choice Examinations?

Science.gov (United States)

Carnegie, Jacqueline A.

2017-01-01

Summative evaluation for large classes of first- and second-year undergraduate courses often involves the use of multiple choice question (MCQ) exams in order to provide timely feedback. Several versions of those exams are often prepared via computer-based question scrambling in an effort to deter cheating. An important parameter to consider when…

Stereotactic radiotherapy of meningiomas compressing optical pathways

International Nuclear Information System (INIS)

Hamm, Klaus-Detlef; Henzel, Martin; Gross, Markus W.; Surber, Gunnar; Kleinert, Gabriele; Engenhart-Cabillic, Rita

2006-01-01

Purpose: Microsurgical resection is usually the treatment of choice for meningiomas, especially for those that compress the optical pathways. However, in many cases of skull-base meningiomas a high risk of neurological deficits and recurrences exist in cases where the complete tumor removal was not possible. In such cases (fractionated) stereotactic radiotherapy (SRT) can offer an alternative treatment option. We evaluated the local control rate, symptomatology, and toxicity. Patients and Methods: Between 1997 and 2003, 183 patients with skull-base meningiomas were treated with SRT, among them were 65 patients with meningiomas that compressed optical pathways (64 benign, 1 atypical). Of these 65 cases, 20 were treated with SRT only, 27 were subtotally resected before SRT, and 18 underwent multiple tumor resections before SRT. We investigated the results until 2005, with a median follow-up of 45 months (range, 22-83 months). The tumor volume (TV = gross tumor volume) ranged from 0.61 to 90.20 cc (mean, 18.9 cc). Because of the risk of new visual disturbances, the dose per fraction was either 2 or 1.8 Gy for all patients, to a total dose of 50 to 60 Gy. Results: The overall survival and the progression-free survival rates for 5 years were assessed to 100% in this patient group. To date, no progression for these meningiomas have been observed. Quantitatively, tumor shrinkage of more than 20%, or more than 2 mm in diameter, was proved in 35 of the 65 cases after SRT. In 29 of the 65 patients, at least 1 of the symptoms improved. On application of the Common Toxicity Criteria (CTC), acute toxicity (Grade 3) was seen in 1 case (worsening of conjunctivitis). Another 2 patients developed late toxicity by LENT-SOMA score, 1 x Grade 1 and 1 x Grade 3 (field of vision loss). Conclusion: As a low-risk and effective treatment option for tumor control, SRT with 1.8 to 2.0 Gy per fraction can also be recommended in case of meningiomas that compress optical pathways. An

Efficiency of Choice Set Generation Methods for Bicycle Routes

DEFF Research Database (Denmark)

Halldórsdóttir, Katrín; Rieser-Schüssler, Nadine; W. Axhausen, Kay

behaviour, observed choices and alternatives composing the choice set of each cyclist are necessary. However, generating the alternative choice sets can prove challenging. This paper analyses the efficiency of various choice set generation methods for bicycle routes in order to contribute to our...... travelling information with GPS loggers, compared to self-reported RP data, is more accurate geographic locations and routes. Also, the GPS traces give more reliable information on times and prevent trip underreporting, and it is possible to collect information on many trips by the same person without...

Processing of recognition information and additional cues: A model-based analysis of choice, confidence, and response time

Directory of Open Access Journals (Sweden)

Andreas Glockner

2011-02-01

Full Text Available Research on the processing of recognition information has focused on testing the recognition heuristic (RH. On the aggregate, the noncompensatory use of recognition information postulated by the RH was rejected in several studies, while RH could still account for a considerable proportion of choices. These results can be explained if either a a part of the subjects used RH or b nobody used it but its choice predictions were accidentally in line with predictions of the strategy used. In the current study, which exemplifies a new approach to model testing, we determined individuals' decision strategies based on a maximum-likelihood classification method, taking into account choices, response times and confidence ratings simultaneously. Unlike most previous studies of the RH, our study tested the RH under conditions in which we provided information about cue values of unrecognized objects (which we argue is fairly common and thus of some interest. For 77.5% of the subjects, overall behavior was best explained by a compensatory parallel constraint satisfaction (PCS strategy. The proportion of subjects using an enhanced RH heuristic (RHe was negligible (up to 7.5%; 15% of the subjects seemed to use a take the best strategy (TTB. A more-fine grained analysis of the supplemental behavioral parameters conditional on strategy use supports PCS but calls into question process assumptions for apparent users of RH, RHe, and TTB within our experimental context. Our results are consistent with previous literature highlighting the importance of individual strategy classification as compared to aggregated analyses.

Modelling Choice of Information Sources

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Agha Faisal Habib Pathan

2013-04-01

Full Text Available This paper addresses the significance of traveller information sources including mono-modal and multimodal websites for travel decisions. The research follows a decision paradigm developed earlier, involving an information acquisition process for travel choices, and identifies the abstract characteristics of new information sources that deserve further investigation (e.g. by incorporating these in models and studying their significance in model estimation. A Stated Preference experiment is developed and the utility functions are formulated by expanding the travellers' choice set to include different combinations of sources of information. In order to study the underlying choice mechanisms, the resulting variables are examined in models based on different behavioural strategies, including utility maximisation and minimising the regret associated with the foregone alternatives. This research confirmed that RRM (Random Regret Minimisation Theory can fruitfully be used and can provide important insights for behavioural studies. The study also analyses the properties of travel planning websites and establishes a link between travel choices and the content, provenance, design, presence of advertisements, and presentation of information. The results indicate that travellers give particular credence to governmentowned sources and put more importance on their own previous experiences than on any other single source of information. Information from multimodal websites is more influential than that on train-only websites. This in turn is more influential than information from friends, while information from coachonly websites is the least influential. A website with less search time, specific information on users' own criteria, and real time information is regarded as most attractive

Pulsed Radiation Therapy With Concurrent Cisplatin Results in Superior Tumor Growth Delay in a Head and Neck Squamous Cell Carcinoma Murine Model

Energy Technology Data Exchange (ETDEWEB)

Meyer, Kurt; Krueger, Sarah A.; Kane, Jonathan L.; Wilson, Thomas G.; Hanna, Alaa; Dabjan, Mohamad; Hege, Katie M.; Wilson, George D.; Grills, Inga; Marples, Brian, E-mail: brian.marples@beaumont.edu

2016-09-01

Purpose: To assess the efficacy of 3-week schedules of low-dose pulsed radiation treatment (PRT) and standard radiation therapy (SRT), with concurrent cisplatin (CDDP) in a head and neck squamous cell carcinoma xenograft model. Methods and Materials: Subcutaneous UT-SCC-14 tumors were established in athymic NIH III HO female mice. A total of 30 Gy was administered as 2 Gy/d, 5 d/wk for 3 weeks, either by PRT (10 × 0.2 Gy/d, with a 3-minute break between each 0.2-Gy dose) or SRT (2 Gy/d, uninterrupted delivery) in combination with concurrent 2 mg/kg CDDP 3 times per week in the final 2 weeks of radiation therapy. Treatment-induced growth delays were defined from twice-weekly tumor volume measurements. Tumor hypoxia was assessed by {sup 18}F-fluoromisonidazole positron emission tomography imaging, and calculated maximum standardized uptake values compared with tumor histology. Tumor vessel density and hypoxia were measured by quantitative immunohistochemistry. Normal tissues effects were evaluated in gut and skin. Results: Untreated tumors grew to 1000 mm{sup 3} in 25.4 days (±1.2), compared with delays of 62.3 days (±3.5) for SRT + CDDP and 80.2 days (±5.0) for PRT + CDDP. Time to reach 2× pretreatment volume ranged from 8.2 days (±1.8) for untreated tumors to 67.1 days (±4.7) after PRT + CDDP. Significant differences in tumor growth delay were observed for SRT versus SRT + CDDP (P=.04), PRT versus PRT + CDDP (P=.035), and SRT + CDDP versus PRT + CDDP (P=.033), and for survival between PRT versus PRT + CDDP (P=.017) and SRT + CDDP versus PRT + CDDP (P=.008). Differences in tumor hypoxia were evident by {sup 18}F-fluoromisonidazole positron emission tomography imaging between SRT and PRT (P=.025), although not with concurrent CDDP. Tumor vessel density differed between SRT + CDDP and PRT + CDDP (P=.011). No differences in normal tissue parameters were seen. Conclusions: Concurrent CDDP was more effective in combination PRT than SRT at

Cultures of choice: towards a sociology of choice as a cultural phenomenon.

Science.gov (United States)

Schwarz, Ori

2017-09-07

The article explores different ways to conceptualize the relationship between choice and culture. These two notions are often constructed as opposites: while sociologies of modernization (such as Giddens') portray a shift from cultural traditions to culturally disembedded choice, dispositional sociologies (such as Bourdieu's) uncover cultural determination as the hidden truth behind apparent choice. However, choice may be real and cultural simultaneously. Culture moulds choice not only by inculcating dispositions or shaping repertoires of alternatives, but also by offering culturally specific choice practices, ways of choosing embedded in meaning, normativity, and materiality; and by shaping attributions of choice in everyday life. By bringing together insights from rival schools, I portray an outline for a comparative cultural sociology of choice, and demonstrate its purchase while discussing the digitalization of choice; and cultural logics that shape choice attribution in ways opposing neoliberal trends. © London School of Economics and Political Science 2017.

Are vent crab behavioral preferences adaptations for habitat choice?

Science.gov (United States)

Dahms, Hans-Uwe; Tseng, Li-Chun; Hwang, Jiang-Shiou

2017-01-01

Hydrothermal vent organisms are adapted to their extreme and patchily distributed habitats. They are expected to have evolved mechanisms that keep them in their specific habitation. Since little is known about the recruitment or habitat selection of HV organisms such as brachyurans, we examined the properties of several hydrothermal vent-associated cues on the behavior of the hydrothermal vent (HV) crab Xenograpsus testudinatus in the laboratory that were contrasted by the offering of non-vent cues. This crab species is endemic and dominates the vent fauna of Turtle Island off the NE coast of Taiwan. HV crabs were separately and in combination offered the following vent-specific cues: (1) sulfuric sediment, (3) air-bubbling, (4) elevated temperature, (5) dead settled zooplankton, (7) other crabs, and (8) shade. The non-vent-specific cues were: (2) quarz sediment, (6) dead fish, (8) light. These cues were provided on either side of a two-choice chamber. The movement of individual crabs was monitored: as initial and final choices, and as the proportion of time the crabs spent in each compartment (resident time). Cues were offered alone and no such cue as a control in the same set-up. Sulfuric sediments and dead fish were significantly more attractive to females, and other crabs irrespective of gender were significantly more attractive to males. When compared to expected distributions, crabs, irrespective of gender, significantly avoided light and tended to select other crabs, air-bubbling, sulfuric sediment, elevated temperature, dead fish, dead zooplankton, and quarz sediments in the order of decreasing importance. Data do not support the hypothesis that dead settled zooplankton was particularly attractive nor that the other gender was selected. A combination of several vent-associated cues (sulfuric sediment, elevated temperature, air-bubbling) facilitated the strongest attraction to the crabs as reflected by all response variables. The 'first choice' responses

Health concern, food choice motives, and attitudes toward healthy eating: the mediating role of food choice motives.

Science.gov (United States)

Sun, Yu-Hua Christine

2008-07-01

This study addresses how various health concerns might influence not only consumers' food choice motives but also consumers' subsequent attitudes toward healthy eating. This study expects that those consumers with greater health concerns would have different food choice motives and better attitudes toward healthy eating. A self-completion questionnaire was used to gather information. Participants, a random sample of 500 undergraduate students from a national university in Taipei, Taiwan, provided a total of 456 usable questionnaires, representing a valid response rate of 91%. The average age of the respondents at the time of the survey was 21 years and 63% of respondents were females. The relationship between health concern and healthy eating attitudes was confirmed. The relationship between health concern of developing diseases and attitudes toward healthy eating was fully mediated by food choice motives. However, the relationship between calorie consumption health concern and healthy eating attitudes was only partially mediated by food choice motives. Implications of these findings are discussed.

Action and valence modulate choice and choice-induced preference change.

Directory of Open Access Journals (Sweden)

Raphael Koster

Full Text Available Choices are not only communicated via explicit actions but also passively through inaction. In this study we investigated how active or passive choice impacts upon the choice process itself as well as a preference change induced by choice. Subjects were tasked to select a preference for unfamiliar photographs by action or inaction, before and after they gave valuation ratings for all photographs. We replicate a finding that valuation increases for chosen items and decreases for unchosen items compared to a control condition in which the choice was made post re-evaluation. Whether choice was expressed actively or passively affected the dynamics of revaluation differently for positive and negatively valenced items. Additionally, the choice itself was biased towards action such that subjects tended to choose a photograph obtained by action more often than a photographed obtained through inaction. These results highlight intrinsic biases consistent with a tight coupling of action and reward and add to an emerging understanding of how the mode of action itself, and not just an associated outcome, modulates the decision making process.

Recent evolution of italian households’ equity portfolio choices: an empirical investigation

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Attilio Gardini

2013-05-01

Full Text Available We study Italian households’ portfolio choices, with a special focus on equity investments, by analysing jointly time series and cross-sectional portfolio data. We investigate the temporal evolution of the actual composition of Italian households’ investments in order to explain their portfolio choices and to detect possible determinants of the observed disequilibria phenomena. Moreover, we model the stock market participation choice by using probit regression techniques and we test for parameter stability over time. Instability of participation parameters and a peculiar evolution of Italian households’ portfolios pointed out by our concurrent analysis of cross-sectional and time series data seem to confirm the distance of Italian households’ financial decisions from the rational choice predicted by the Markowitz model. In particular, we find that the housing market bubbles interact strongly with the stock market and financial institutions seem to be unable to advise investors suggesting optimal portfolio choices. The deep reason behind these facts may be the bounded education of investors, in particular the low financial literacy of Italian households.

A narrative approach to understand students’ identities and choices

DEFF Research Database (Denmark)

Holmegaard, Henriette Tolstrup; Ulriksen, Lars; Madsen, Lene Møller

2015-01-01

This chapter demonstrates how narrative theory in general, and narrative psychology in particular, contribute to understand how students make meaning of their choice of post-secondary studies. In particular two central ideas within the theory are unfolded; the concept of identity and the concept...... of time. The applicability of the theory is discussed using empirical examples. The chapter argues that a narrative approach provides an understanding of choice of study as continuous processes where individuals work on their identities in terms of negotiating and constructing a coherent choice...... of the chapter consequences for future research are discussed as well as how this approach to students’ choices of study contributes to our understanding of students’ science, technology, engineering and mathematics (STEM) choices....

Using respondent uncertainty to mitigate hypothetical bias in a stated choice experiment

Science.gov (United States)

Richard C. Ready; Patricia A. Champ; Jennifer L. Lawton

2010-01-01

In a choice experiment study, willingness to pay for a public good estimated from hypothetical choices was three times as large as willingness to pay estimated from choices requiring actual payment. This hypothetical bias was related to the stated level of certainty of respondents. We develop protocols to measure respondent certainty in the context of a choice...

Informed Food Choice

DEFF Research Database (Denmark)

Coff, Christian

2014-01-01

of informed food choice. An informed food choice is an enlightened food choice made by the individual based on the information made available. Food choices are made when shopping for food or when eating/drinking, and information is believed to give clarity to the options by increasing market transparency......Food production and consumption influence health, the environment, social structures, etc. For this reason consumers are increasingly interested in information about these effects. Disclosure of information about the consequences of food production and consumption is essential for the idea......, supporting rationality (the best choice), consumers’ self-governance (autonomy) and life coherence (integrity). On a practical level, informed food choice remains an ideal to strive for, as information on food often is inadequate....

Project Choice: Lessons Learned.

Science.gov (United States)

Ewing Marion Kauffman Foundation, Kansas City, MO.

Project Choice began with a simple goal: to increase the number of inner-city students who graduate from high school on time and become productive members of society. To that end, Ewing M. Kauffman, his Foundation, and associates designed and implemented a program that promised postsecondary education or training to some students in the Kansas…

Investigating intertemporal choice through experimental evolutionary robotics.

Science.gov (United States)

Paglieri, Fabio; Parisi, Domenico; Patacchiola, Massimiliano; Petrosino, Giancarlo

2015-06-01

In intertemporal choices, subjects face a trade-off between value and delay: achieving the most valuable outcome requires a longer time, whereas the immediately available option is objectively poorer. Intertemporal choices are ubiquitous, and comparative studies reveal commonalities and differences across species: all species devalue future rewards as a function of delay (delay aversion), yet there is a lot of inter-specific variance in how rapidly such devaluation occurs. These differences are often interpreted in terms of ecological rationality, as depending on environmental factors (e.g., feeding ecology) and the physiological and morphological constraints of different species (e.g., metabolic rate). Evolutionary hypotheses, however, are hard to verify in vivo, since it is difficult to observe precisely enough real environments, not to mention ancestral ones. In this paper, we discuss the viability of an approach based on evolutionary robotics: in Study 1, we evolve robots without a metabolism in five different ecologies; in Study 2, we evolve metabolic robots (i.e., robots that consume energy over time) in three different ecologies. The intertemporal choices of the robots are analyzed both in their ecology and under laboratory conditions. Results confirm the generality of delay aversion and the usefulness of studying intertemporal choice through experimental evolutionary robotics. Copyright © 2015 Elsevier B.V. All rights reserved.

The Influence of Different Performance Level of Fencers on Simple and Choice Reaction Time

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Štefan Balkó

2016-09-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n4p391   In many sport disciplines reaction time plays a key role in the sport performance. It is good to point out for example ball games or fighting sports (fencing, karate etc.. The research is focused on detection of the differences in the simple and choice reaction time during visual stimulation among elite, sub-elite fencers and beginners. For the measurement a Fitrosword device and the SWORD software were used. An additional stimulus was added during measuring which should increase the overall number of stimuli, but shouldn’t force fencer to any reaction whatsoever. The results from presented study can be compared with Hicks law. The next focus of the study was to identify the difference in reaction time during two different movement tasks with different complexity movement requirements. The research was built up on a hypothesis that the results will differ among different performance groups of fencers. The difference however was overt among beginners and elite fencers (p = 0.0088, d = 0.5 in reaction time during different movement tasks (direct hit vs. lunge. The results of this research could be useful to trainers for training process organisation and increase the effectivity of muscle coordination during several movements in fencing.

The immediate effect of lumbar spine patterns of neuromuscular joint facilitation in young amateur baseball players.

Science.gov (United States)

Huo, Ming; Maruyama, Hitoshi; Kaneko, Takasumi; Naito, Daiki; Koiso, Yuta

2013-12-01

[Purpose] The aim of the study was to investigate the changes in baseball pitching velocity, the functional reach test (FR) and the simple reaction times (SRT) in young amateur baseball players after lumbar spine patterns of neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 11 young amateur baseball players. An NJF intervention and a proprioceptive neuromuscular facilitation (PNF) intervention were performed. The interventions were performed one after the other with one week between them. The order of the interventions was completely randomized. [Methods] The baseball pitching velocity, the FR and the SRT were evaluated before and after treatment. [Results] In the NJF group, there were significant differences in baseball pitching velocity, FR and SRT after treatment. In the PNF group, there was a significant difference in SRT after treatment. [Conclusion] NJF intervention shortens the SRT, increases the baseball pitching velocity and FR, and may be recommended to improve performance in baseball players.

[Continuing medical education: how to write multiple choice questions].

Science.gov (United States)

Soler Fernández, R; Méndez Díaz, C; Rodríguez García, E

2013-06-01

Evaluating professional competence in medicine is a difficult but indispensable task because it makes it possible to evaluate, at different times and from different perspectives, the extent to which the knowledge, skills, and values required for exercising the profession have been acquired. Tests based on multiple choice questions have been and continue to be among the most useful tools for objectively evaluating learning in medicine. When these tests are well designed and correctly used, they can stimulate learning and even measure higher cognitive skills. Designing a multiple choice test is a difficult task that requires knowledge of the material to be tested and of the methodology of test preparation as well as time to prepare the test. The aim of this article is to review what can be evaluated through multiple choice tests, the rules and guidelines that should be taken into account when writing multiple choice questions, the different formats that can be used, the most common errors in elaborating multiple choice tests, and how to analyze the results of the test to verify its quality. Copyright © 2012 SERAM. Published by Elsevier Espana. All rights reserved.

The Internal and External Factors of Vocational Path Choice

OpenAIRE

Urbanavičiūtė, Ieva

2010-01-01

The main objective of the doctoral thesis was to analyze the features of one’s vocational path during the time of undergraduate studies. Undergraduate studies can be treated as a pathway of transition from school to the world of work. Therefore, it is especially important to identify what makes vocational choice successful during this period of time. In the study, several psychological success indicators of vocational path choice were distinguished. Moreover, the following factors were analyz...

Retirement investment theory explains patterns in songbird nest-site choice

Science.gov (United States)

Streby, Henry M.; Refsnider, Jeanine M.; Peterson, Sean M.; Andersen, David E.

2014-01-01

When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

Influence of learning strategy on response time during complex value-based learning and choice.

Directory of Open Access Journals (Sweden)

Shiva Farashahi

Full Text Available Measurements of response time (RT have long been used to infer neural processes underlying various cognitive functions such as working memory, attention, and decision making. However, it is currently unknown if RT is also informative about various stages of value-based choice, particularly how reward values are constructed. To investigate these questions, we analyzed the pattern of RT during a set of multi-dimensional learning and decision-making tasks that can prompt subjects to adopt different learning strategies. In our experiments, subjects could use reward feedback to directly learn reward values associated with possible choice options (object-based learning. Alternatively, they could learn reward values of options' features (e.g. color, shape and combine these values to estimate reward values for individual options (feature-based learning. We found that RT was slower when the difference between subjects' estimates of reward probabilities for the two alternative objects on a given trial was smaller. Moreover, RT was overall faster when the preceding trial was rewarded or when the previously selected object was present. These effects, however, were mediated by an interaction between these factors such that subjects were faster when the previously selected object was present rather than absent but only after unrewarded trials. Finally, RT reflected the learning strategy (i.e. object-based or feature-based approach adopted by the subject on a trial-by-trial basis, indicating an overall faster construction of reward value and/or value comparison during object-based learning. Altogether, these results demonstrate that the pattern of RT can be informative about how reward values are learned and constructed during complex value-based learning and decision making.

Food choice decision-making by women with gestational diabetes.

Science.gov (United States)

Hui, Amy Leung; Sevenhuysen, Gustaaf; Harvey, Dexter; Salamon, Elizabeth

2014-02-01

To enhance the dietary education presented to women with gestational diabetes (GDM) by exploring the reasons and experiences that women with GDM reported in making their food-choice decisions after receipt of dietary education from a healthcare professional. Food Choice Map (FCM) semi-structured in-depth interviews were conducted with 30 women with GDM living in the Winnipeg area during their pregnancies. Verbatim transcripts were generated from the interviews. A constant comparative method was used to generate common themes to answer research inquiries. Personal food preferences, hunger and cravings were the main factors affecting food choice decision-making in women with GDM. Although the information from healthcare professionals was 1 factor that affected food choice decision-making for most of the participants, more than half of the women, including all the women who were on insulin, reported difficulties in quick adaptation to dietary management in a limited time period. Information from other sources such as family members, friends, and internet were used to cope with the adaptation. These difficulties led to a sense of decreased control of GDM and were accompanied by frustration, especially for women taking insulin. Food choice decision-making varied for this group of women with GDM. Knowledge and information aided in making healthy food choices and in portion control. However, balancing individual needs and blood glucose control in a short time period was felt to be difficult and created frustration. The findings suggested that dietary consultation needs to be personalized and to be time sensitive to promote confidence in self-control. Copyright © 2014 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

Overlapping defaults. The case of intertemporal choices

Directory of Open Access Journals (Sweden)

Sawicki Przemysław

2017-12-01

Full Text Available People make different choices depending on which decision is the default option. In intertemporal choices, the default option is typically imposed externally. For example, people expect more for delaying the gain (default in the present than are willing to pay for accelerating the future gain over the same period (default in the future. We claim that apart from the external default, people’s choices are also influenced by the internal (natural default such as the time perspective resulting in the reference point in the present. By manipulating the congruency between the internal and external defaults, we show that incongruence between defaults decreases the strength of discounting of gains, but not of losses.

Grading School Choice: Evaluating School Choice Programs by the Friedman Gold Standard. School Choice Issues in Depth

Science.gov (United States)

Enlow, Robert C.

2008-01-01

In 2004, The Friedman Foundation for Educational Choice published a report titled "Grading Vouchers: Ranking America's School Choice Programs." Its purpose was to measure every existing school choice program against the gold standard set by Milton and Rose Friedman: that the most effective way to improve K-12 education and thus ensure a stable…

Pairwise Choice Markov Chains

OpenAIRE

Ragain, Stephen; Ugander, Johan

2016-01-01

As datasets capturing human choices grow in richness and scale---particularly in online domains---there is an increasing need for choice models that escape traditional choice-theoretic axioms such as regularity, stochastic transitivity, and Luce's choice axiom. In this work we introduce the Pairwise Choice Markov Chain (PCMC) model of discrete choice, an inferentially tractable model that does not assume any of the above axioms while still satisfying the foundational axiom of uniform expansio...

Deep Brain Stimulation of the Subthalamic Nucleus Does Not Affect the Decrease of Decision Threshold during the Choice Process When There Is No Conflict, Time Pressure, or Reward.

Science.gov (United States)

Leimbach, Friederike; Georgiev, Dejan; Litvak, Vladimir; Antoniades, Chrystalina; Limousin, Patricia; Jahanshahi, Marjan; Bogacz, Rafal

2018-06-01

During a decision process, the evidence supporting alternative options is integrated over time, and the choice is made when the accumulated evidence for one of the options reaches a decision threshold. Humans and animals have an ability to control the decision threshold, that is, the amount of evidence that needs to be gathered to commit to a choice, and it has been proposed that the subthalamic nucleus (STN) is important for this control. Recent behavioral and neurophysiological data suggest that, in some circumstances, the decision threshold decreases with time during choice trials, allowing overcoming of indecision during difficult choices. Here we asked whether this within-trial decrease of the decision threshold is mediated by the STN and if it is affected by disrupting information processing in the STN through deep brain stimulation (DBS). We assessed 13 patients with Parkinson disease receiving bilateral STN DBS six or more months after the surgery, 11 age-matched controls, and 12 young healthy controls. All participants completed a series of decision trials, in which the evidence was presented in discrete time points, which allowed more direct estimation of the decision threshold. The participants differed widely in the slope of their decision threshold, ranging from constant threshold within a trial to steeply decreasing. However, the slope of the decision threshold did not depend on whether STN DBS was switched on or off and did not differ between the patients and controls. Furthermore, there was no difference in accuracy and RT between the patients in the on and off stimulation conditions and healthy controls. Previous studies that have reported modulation of the decision threshold by STN DBS or unilateral subthalamotomy in Parkinson disease have involved either fast decision-making under conflict or time pressure or in anticipation of high reward. Our findings suggest that, in the absence of reward, decision conflict, or time pressure for decision

Food Choice Architecture: An Intervention in a Secondary School and its Impact on Students’ Plant-based Food Choices

Directory of Open Access Journals (Sweden)

Hannah Ensaff

2015-06-01

Full Text Available With growing evidence for the positive health outcomes associated with a plant-based diet, the study’s purpose was to examine the potential of shifting adolescents’ food choices towards plant-based foods. Using a real world setting of a school canteen, a set of small changes to the choice architecture was designed and deployed in a secondary school in Yorkshire, England. Focussing on designated food items (whole fruit, fruit salad, vegetarian daily specials, and sandwiches containing salad the changes were implemented for six weeks. Data collected on students’ food choice (218,796 transactions enabled students’ (980 students selections to be examined. Students’ food choice was compared for three periods: baseline (29 weeks; intervention (six weeks; and post-intervention (three weeks. Selection of designated food items significantly increased during the intervention and post-intervention periods, compared to baseline (baseline, 1.4%; intervention 3.0%; post-intervention, 2.2% χ2(2 = 68.1, p < 0.001. Logistic regression modelling also revealed the independent effect of the intervention, with students 2.5 times as likely (p < 0.001 to select the designated food items during the intervention period, compared to baseline. The study’s results point to the influence of choice architecture within secondary school settings, and its potential role in improving adolescents’ daily food choices.

Sequential and simultaneous choices: testing the diet selection and sequential choice models.

Science.gov (United States)

Freidin, Esteban; Aw, Justine; Kacelnik, Alex

2009-03-01

We investigate simultaneous and sequential choices in starlings, using Charnov's Diet Choice Model (DCM) and Shapiro, Siller and Kacelnik's Sequential Choice Model (SCM) to integrate function and mechanism. During a training phase, starlings encountered one food-related option per trial (A, B or R) in random sequence and with equal probability. A and B delivered food rewards after programmed delays (shorter for A), while R ('rejection') moved directly to the next trial without reward. In this phase we measured latencies to respond. In a later, choice, phase, birds encountered the pairs A-B, A-R and B-R, the first implementing a simultaneous choice and the second and third sequential choices. The DCM predicts when R should be chosen to maximize intake rate, and SCM uses latencies of the training phase to predict choices between any pair of options in the choice phase. The predictions of both models coincided, and both successfully predicted the birds' preferences. The DCM does not deal with partial preferences, while the SCM does, and experimental results were strongly correlated to this model's predictions. We believe that the SCM may expose a very general mechanism of animal choice, and that its wider domain of success reflects the greater ecological significance of sequential over simultaneous choices.

Pregnant women's choice of birthing hospital

DEFF Research Database (Denmark)

Tayyari Dehbarez, Nasrin; Lou, Stina; Uldbjerg, Niels

2017-01-01

design was used and women were recruited during their first pregnancy-related visit to a general practitioner. The interviews were conducted using a semi-structured interview guide, and a thematic analysis of the data was carried out. RESULTS: Women made their hospital choice decision independently......OBJECTIVE: To investigate pregnant women's decision making in relation to their choice of birthing hospital and, in particular, their priorities regarding hospital characteristics. METHODS: The focus of this study was the choice of birthing hospital among pregnant women. A qualitative interview...... and they relied extensively on their own or peers' experiences. Travel distance played a role, but some women were willing to incur longer travel times to give birth at a specialized hospital in order to try to reduce the risks (in case of unexpected events). The women associated the presence of specialized...

Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

Science.gov (United States)

Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

2013-01-01

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

Role of postoperative radiation therapy after stabilization of fractures caused by metastatic disease

Energy Technology Data Exchange (ETDEWEB)

Townsend, Patrick W; Smalley, Stephen R; Cozad, Scott C; Rosenthal, Howard G; Hassanein, Ruth E S

1995-01-01

Purpose: Although orthopedic stabilization is frequently performed for pathological fractures caused by metastatic disease, no data is available to support the value of postoperative radiation therapy (S+RT) in this setting. Methods and Materials: We reviewed 64 orthopedic stabilization procedures in 60 consecutive patients with metastatic disease to previously unirradiated weight-bearing bones with pathological or impending pathological fracture (femur 91%). Thirty-five sites that received adjuvant S+RT were compared to 29 sites that were treated with surgery alone (SA). Many potential prognostic variables were evaluated. Endpoints were: functional status (FS) of the extremity (1 = normal pain free use; 2 = normal use with pain, 3 significantly limited use; 4 = nonfunctional extremity), subsequent orthopedic procedures to the same site, and survival following surgery. Results: At the univariate level, S+RT (p = 0.02) and prefracture FS (p 0.04) were the only significant predictors of patients achieving an FS of 1 or 2 after surgery. On multivariate analysis, only postoperative RT was significantly (p = 0.02) associated with attaining FS of 1 or 2 after surgery. The predicted probability of achieving FS 1 or 2 at any time was 53% for S+RT vs. 11.5% or SA (multiple logistic regression, p < 0.01). Evaluation of FS following surgery revealed that S+RT group had significantly better function in the 1-3, 3-6, and 6-12 month postoperative periods (chi-square, p < 0.04 for each time period). Second orthopedic procedures to the same site were more common in the SA group than the S+RT group (log rank, p = 0.03). Actuarial median survival of S group was 3.3 months compared with 12.4 months for the S+RT group (log rank, p = 0.02), confirming the beneficial association with survival shown by the multivariate Cox regression analysis (p = 0.025). Conclusion: Although this retrospective study is subject to possible biases, several analyses adjusting for numerous prognostic

Expanding the Nudge : Designing Choice Contexts and Choice Contents

OpenAIRE

Grill, Kalle

2014-01-01

To nudge is to design choice contexts in order to improve choice outcomes. Richard Thaler and Cass Sunstein emphatically endorse nudging but reject more restrictive means. In contrast, I argue that the behavioral psychology that motivates nudging also motivates what may be called jolting—i.e. the design of choice content. I defend nudging and jolting by distinguishing them from the sometimes oppressive means with which they can be im- plemented, by responding to some common arguments against ...

Treatment Outcomes from 68Ga-PSMA PET/CT-Informed Salvage Radiation Treatment in Men with Rising PSA After Radical Prostatectomy: Prognostic Value of a Negative PSMA PET.

Science.gov (United States)

Emmett, Louise; van Leeuwen, Pim J; Nandurkar, Rohan; Scheltema, Matthijs J; Cusick, Thomas; Hruby, George; Kneebone, Andrew; Eade, Thomas; Fogarty, Gerald; Jagavkar, Raj; Nguyen, Quoc; Ho, Bao; Joshua, Anthony M; Stricker, Phillip

2017-12-01

68 Ga-PSMA (prostate-specific membrane antigen) PET/CT is increasingly used in men with prostate-specific antigen (PSA) failure after radical prostatectomy (RP) to triage those who will benefit from salvage radiation treatment (SRT). This study examines the value of PSMA-informed SRT in improving treatment outcomes in the context of biochemical failure after RP. Methods: We analyzed men with rising PSA after RP with PSA readings between 0.05 and 1.0 ng/mL, considered eligible for SRT at the time of PSMA. For each patient, clinical and pathologic features as well as scan results, including site of PSMA-positive disease, number of lesions, and a certainty score, were documented. Subsequent management, including SRT, and most recent PSA were recorded using medical records. Treatment response was defined as both PSA ≤ 0.1 ng/mL and >50% reduction in PSA. Multivariate logistic regression analysis was performed for association of clinical variables and treatment response to SRT. Results: One hundred sixty-four men were included. PSMA was positive in 62% ( n = 102/164): 38 of 102 in the prostatic fossa, 41 of 102 in pelvic nodes, and 23 of 102 distantly. Twenty-four patients received androgen-deprivation therapy (ADT) and were excluded for outcomes analysis. In total, 99 of 146 received SRT with a median follow-up after radiation treatment of 10.5 mo (interquartile range, 6-14 mo). Overall treatment response after SRT was 72% ( n = 71/99). Forty-five percent ( n = 27/60) of patients with a negative PSMA underwent SRT whereas 55% (33/60) did not. In men with a negative PSMA who received SRT, 85% ( n = 23/27) demonstrated a treatment response, compared with a further PSA increase in 65% (22/34) in those not treated. In 36 of 99 patients with disease confined to the prostate fossa on PSMA, 81% ( n = 29/36) responded to SRT. In total, 26 of 99 men had nodal disease on PSMA, of whom 61% ( n = 16/26) had treatment response after SRT. On multivariate logistic regression

Rates of Second Malignancies After Definitive Local Treatment for Ductal Carcinoma In Situ of the Breast

International Nuclear Information System (INIS)

Shaitelman, Simona F.; Grills, Inga S.; Kestin, Larry L.; Ye Hong; Nandalur, Sirisha; Huang Jiayi; Vicini, Frank A.

2011-01-01

Purpose: We analyzed the risk of second malignancies developing in patients with ductal carcinoma in situ (DCIS) undergoing surgery and radiotherapy (S+RT) vs. surgery alone. Methods and Materials: The S+RT cohort consisted of 256 women treated with breast-conserving therapy at William Beaumont Hospital. The surgery alone cohort consisted of 2,788 women with DCIS in the regional Surveillance, Epidemiology, and End Results database treated during the same time period. A matched-pair analysis was performed in which each S+RT patient was randomly matched with 8 surgery alone patients (total of 2,048 patients). Matching criteria included age ± 2 years. The rates of second malignancies were analyzed overall and as contralateral breast vs. non-breast cancers and by organ system. Results: Median follow-up was 13.7 years for the S+RT cohort and 13.3 years for the surgery alone cohort. The overall 10-/15-year rates of second malignancies among the S+RT and surgery alone cohorts were 14.2%/24.2% and 16.4%/22.6%, respectively (p = 0.668). The 15-year second contralateral breast cancer rate was 14.2% in the S+RT cohort and 10.3% in the surgery alone cohort (p = 0.439). The 15-year risk of a second non-breast malignancy was 14.2% for the S+RT cohort and 13.4% for the surgery alone cohort (p = 0.660). When analyzed by organ system, the 10- and 15-year rates of second malignancies did not differ between the S+RT and surgery alone cohorts for pulmonary, gastrointestinal, central nervous system, gynecologic, genitourinary, lymphoid, sarcomatoid, head and neck, or unknown primary tumors. Conclusions: Compared with surgery alone, S+RT is not associated with an overall increased risk of second malignancies in women with DCIS.

Parameter Estimation for Thurstone Choice Models

Energy Technology Data Exchange (ETDEWEB)

Vojnovic, Milan [London School of Economics (United Kingdom); Yun, Seyoung [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-04-24

We consider the estimation accuracy of individual strength parameters of a Thurstone choice model when each input observation consists of a choice of one item from a set of two or more items (so called top-1 lists). This model accommodates the well-known choice models such as the Luce choice model for comparison sets of two or more items and the Bradley-Terry model for pair comparisons. We provide a tight characterization of the mean squared error of the maximum likelihood parameter estimator. We also provide similar characterizations for parameter estimators defined by a rank-breaking method, which amounts to deducing one or more pair comparisons from a comparison of two or more items, assuming independence of these pair comparisons, and maximizing a likelihood function derived under these assumptions. We also consider a related binary classification problem where each individual parameter takes value from a set of two possible values and the goal is to correctly classify all items within a prescribed classification error. The results of this paper shed light on how the parameter estimation accuracy depends on given Thurstone choice model and the structure of comparison sets. In particular, we found that for unbiased input comparison sets of a given cardinality, when in expectation each comparison set of given cardinality occurs the same number of times, for a broad class of Thurstone choice models, the mean squared error decreases with the cardinality of comparison sets, but only marginally according to a diminishing returns relation. On the other hand, we found that there exist Thurstone choice models for which the mean squared error of the maximum likelihood parameter estimator can decrease much faster with the cardinality of comparison sets. We report empirical evaluation of some claims and key parameters revealed by theory using both synthetic and real-world input data from some popular sport competitions and online labor platforms.

A Simulation-Based Dynamic Stochastic Route Choice Model for Evacuation

Directory of Open Access Journals (Sweden)

Xing Zhao

2012-01-01

Full Text Available This paper establishes a dynamic stochastic route choice model for evacuation to simulate the propagation process of traffic flow and estimate the stochastic route choice under evacuation situations. The model contains a lane-group-based cell transmission model (CTM which sets different traffic capacities for links with different turning movements to flow out in an evacuation situation, an actual impedance model which is to obtain the impedance of each route in time units at each time interval and a stochastic route choice model according to the probit-based stochastic user equilibrium. In this model, vehicles loading at each origin at each time interval are assumed to choose an evacuation route under determinate road network, signal design, and OD demand. As a case study, the proposed model is validated on the network nearby Nanjing Olympic Center after the opening ceremony of the 10th National Games of the People's Republic of China. The traffic volumes and clearing time at five exit points of the evacuation zone are calculated by the model to compare with survey data. The results show that this model can appropriately simulate the dynamic route choice and evolution process of the traffic flow on the network in an evacuation situation.

Metro passengers’ route choice model and its application considering perceived transfer threshold

Science.gov (United States)

Jin, Fanglei; Zhang, Yongsheng; Liu, Shasha

2017-01-01

With the rapid development of the Metro network in China, the greatly increased route alternatives make passengers’ route choice behavior and passenger flow assignment more complicated, which presents challenges to the operation management. In this paper, a path sized logit model is adopted to analyze passengers’ route choice preferences considering such parameters as in-vehicle time, number of transfers, and transfer time. Moreover, the “perceived transfer threshold” is defined and included in the utility function to reflect the penalty difference caused by transfer time on passengers’ perceived utility under various numbers of transfers. Next, based on the revealed preference data collected in the Guangzhou Metro, the proposed model is calibrated. The appropriate perceived transfer threshold value and the route choice preferences are analyzed. Finally, the model is applied to a personalized route planning case to demonstrate the engineering practicability of route choice behavior analysis. The results show that the introduction of the perceived transfer threshold is helpful to improve the model’s explanatory abilities. In addition, personalized route planning based on route choice preferences can meet passengers’ diversified travel demands. PMID:28957376

The Effects of Mood, Cognitive Style, and Cognitive Ability on Implicit Learning

Science.gov (United States)

Pretz, Jean E.; Totz, Kathryn Sentman; Kaufman, Scott Barry

2010-01-01

In an experiment with 109 undergraduates, we examined the effect of mood, cognitive style, and cognitive ability on implicit learning in the Artificial Grammar (AG) and Serial Reaction Time (SRT) tasks. Negative mood facilitated AG learning, but had no significant effect on SRT learning. Rational cognitive style predicted greater learning on both…

Child Care Choices, Food Choices, and Children’s Obesity Status

OpenAIRE

Mandal, Bidisha; Powell, Lisa M.

2013-01-01

We evaluate the effect of differences in child care and food environments on obesity among children in the age group of four to six years. To address non-random selection of children into different child care settings, we first predict market price of child care and market wages, and then examine how these affect choice of child care settings and the amount of time children spend in different settings. Using panel data models, we analyze the role of care settings on frequency of consumption o...

The formation of science choices in secondary school

Science.gov (United States)

Cleaves, Anna

2005-04-01

In this paper I examine the formation of post-16 choices over 3 years among higher achieving students with respect to enrolment in post-compulsory science courses. Transcripts from four interviews carried out over 3 years with 72 secondary school students were qualitatively analysed. Students were found to shape their choices for science in a variety of ways across time. The situation regarding science choices hinges on far more dynamic considerations than the stereotypical image of the potential advanced science student, committed to becoming a scientist from an early age. There is an interplay of self-perception with respect to science, occupational images of working scientists, relationship with significant adults and perceptions of school science The findings are informative for science educators and for career guidance professionals who may need to take into account the complexity of young people's choices.

How stimuli presentation format affects visual attention and choice outcomes in choice experiments

DEFF Research Database (Denmark)

Orquin, Jacob Lund; Mueller Loose, Simone

This study analyses visual attention and part-worth utilities in choice experiments across three different choice stimuli presentation formats. Visual attention and choice behaviour in discrete choice experiments are found to be strongly affected by stimuli presentation format. These results...

A multi-institutional analysis comparing adjuvant and salvage radiation therapy for high-risk prostate cancer patients with undetectable PSA after prostatectomy

International Nuclear Information System (INIS)

Budiharto, Tom; Perneel, Christiaan; Haustermans, Karin; Junius, Sara; Tombal, Bertrand; Scalliet, Pierre; Renard, Laurette; Lerut, Evelyne; Vekemans, Kris; Joniau, Steven; Poppel, Hendrik Van

2010-01-01

Background and purpose: In men with adverse pathology at the time of radical prostatectomy (RP), the most appropriate timing to administer radiotherapy (RT) remains a subject for debate. To determine whether salvage radiotherapy (SRT) upon early prostate-specific antigen (PSA) relapse is equivalent to immediate adjuvant radiotherapy (ART) post RP. Material and methods: 130 patients receiving ART and 89 receiving SRT were identified. All had an undetectable PSA after RP. Homogeneous subgroups were built based on the status (±) of lymphatic invasion (LVI) and surgical margins (SM), to allow a comparison of ART and SRT. Biochemical disease-free survival (bDFS) was calculated from the date of surgery and from the end of RT. The multivariate analysis was performed using the Cox Proportional hazard model. Results: In the SM-/LVI- and SM+/LVI- groups, SRT was a significant predictor of a decreased bDFS from the date of surgery, while in the SM+/LVI+ group, there was a trend towards significance. From the end of RT, SRT was also a significant predictor of a decreased bDFS in three patient groups: SM-/LVI-, SM+/LVI- and SM+/LVI+. Gleason score >7 showed to be another factor on multivariate analysis associated with decreased bDFS in the SM-/LVI- group, from the date of surgery and end of RT. Preoperative PSA was a significant predictor in the SM-/LVI- group from the date of RP only. Conclusions: Immediate ART post RP for patients with high risk features in the prostatectomy specimen significantly reduces bDFS after RP compared with early SRT upon PSA relapse.

A Review of Factors Influencing Athletes' Food Choices.

Science.gov (United States)

Birkenhead, Karen L; Slater, Gary

2015-11-01

Athletes make food choices on a daily basis that can affect both health and performance. A well planned nutrition strategy that includes the careful timing and selection of appropriate foods and fluids helps to maximize training adaptations and, thus, should be an integral part of the athlete's training programme. Factors that motivate food selection include taste, convenience, nutrition knowledge and beliefs. Food choice is also influenced by physiological, social, psychological and economic factors and varies both within and between individuals and populations. This review highlights the multidimensional nature of food choice and the depth of previous research investigating eating behaviours. Despite numerous studies with general populations, little exploration has been carried out with athletes, yet the energy demands of sport typically require individuals to make more frequent and/or appropriate food choices. While factors that are important to general populations also apply to athletes, it seems likely, given the competitive demands of sport, that performance would be an important factor influencing food choice. It is unclear if athletes place the same degree of importance on these factors or how food choice is influenced by involvement in sport. There is a clear need for further research exploring the food choice motives of athletes, preferably in conjunction with research investigating dietary intake to establish if intent translates into practice.

A Common Mechanism Underlying Food Choice and Social Decisions

Science.gov (United States)

Krajbich, Ian; Hare, Todd; Bartling, Björn; Morishima, Yosuke; Fehr, Ernst

2015-01-01

People make numerous decisions every day including perceptual decisions such as walking through a crowd, decisions over primary rewards such as what to eat, and social decisions that require balancing own and others’ benefits. The unifying principles behind choices in various domains are, however, still not well understood. Mathematical models that describe choice behavior in specific contexts have provided important insights into the computations that may underlie decision making in the brain. However, a critical and largely unanswered question is whether these models generalize from one choice context to another. Here we show that a model adapted from the perceptual decision-making domain and estimated on choices over food rewards accurately predicts choices and reaction times in four independent sets of subjects making social decisions. The robustness of the model across domains provides behavioral evidence for a common decision-making process in perceptual, primary reward, and social decision making. PMID:26460812

A Common Mechanism Underlying Food Choice and Social Decisions.

Science.gov (United States)

Krajbich, Ian; Hare, Todd; Bartling, Björn; Morishima, Yosuke; Fehr, Ernst

2015-10-01

People make numerous decisions every day including perceptual decisions such as walking through a crowd, decisions over primary rewards such as what to eat, and social decisions that require balancing own and others' benefits. The unifying principles behind choices in various domains are, however, still not well understood. Mathematical models that describe choice behavior in specific contexts have provided important insights into the computations that may underlie decision making in the brain. However, a critical and largely unanswered question is whether these models generalize from one choice context to another. Here we show that a model adapted from the perceptual decision-making domain and estimated on choices over food rewards accurately predicts choices and reaction times in four independent sets of subjects making social decisions. The robustness of the model across domains provides behavioral evidence for a common decision-making process in perceptual, primary reward, and social decision making.

Using School Choice: Analyzing How Parents Access Educational Freedom. School Choice Issues in Depth

Science.gov (United States)

Forster, Greg

2005-01-01

This report provides a summary of the process parents must go through to participate in each of the nation's school choice programs, identifying problem areas in some programs. For the first time in one place, this report collects data on participation in each of the programs in current and previous years. Data are given for the number of students…

Test analysis and research on static choice reaction ability of commercial vehicle drivers

Science.gov (United States)

Zhang, Lingchao; Wei, Lang; Qiao, Jie; Tian, Shun; Wang, Shengchang

2017-03-01

Drivers' choice reaction ability has a certain relation with safe driving. It has important significance to research its influence on traffic safety. Firstly, the paper uses a choice reaction detector developed by research group to detect drivers' choice reaction ability of commercial vehicles, and gets 2641 effective samples. Then by using mathematical statistics method, the paper founds that average reaction time from accident group has no difference with non-accident group, and then introduces a variance rate of reaction time as a new index to replace it. The result shows that the test index choice reaction errors and variance rate of reaction time have positive correlations with accidents. Finally, according to testing results of the detector, the paper formulates a detection threshold with four levels for helping transportation companies to assess commercial vehicles drivers.

Stereotactic radiotherapy using Novalis for skull base metastases developing with cranial nerve symptoms.

Science.gov (United States)

Mori, Yoshimasa; Hashizume, Chisa; Kobayashi, Tatsuya; Shibamoto, Yuta; Kosaki, Katsura; Nagai, Aiko

2010-06-01

Skull base metastases are challenging situations because they often involve critical structures such as cranial nerves. We evaluated the role of stereotactic radiotherapy (SRT) which can give high doses to the tumors sparing normal structures. We treated 11 cases of skull base metastases from other visceral carcinomas. They had neurological symptoms due to cranial nerve involvement including optic nerve (3 patients), oculomotor (3), trigeminal (6), abducens (1), facial (4), acoustic (1), and lower cranial nerves (1). The interval between the onset of cranial nerve symptoms and Novalis SRT was 1 week to 7 months. Eleven tumors of 8-112 ml in volume were treated by Novalis SRT with 30-50 Gy in 10-14 fractions. The tumors were covered by 90-95% isodose. Imaging and clinical follow-up has been obtained in all 11 patients for 5-36 months after SRT. Seven patients among 11 died from primary carcinoma or other visceral metastases 9-36 months after Novalis SRT. All 11 metastatic tumors were locally controlled until the end of the follow-up time or patient death, though retreatment for re-growth was done in 1 patient. In 10 of 11 patients, cranial nerve deficits were improved completely or partially. In some patients, the cranial nerve symptoms were relieved even during the period of fractionated SRT. Novalis SRT is thought to be safe and effective treatment for skull base metastases with involvement of cranial nerves and it may improve cranial nerve symptoms quickly.

Prognostic effect of symptomatic extracranial lesions on survival of recursive partitioning analysis Class III brain metastatic patients treated with stereotactic radiotherapy

Directory of Open Access Journals (Sweden)

Xiu-Jun Chen

2016-01-01

Conclusion: The presence of SELs was a negative prognosis factor for the survival of RPA Class III brain metastatic patients. If RPA Class III brain metastatic patients were without SELs, SRT may be a reasonable treatment option, but if they had SELs, SRT may not be a reasonable treatment due to the short overall survival time and KDT.

WE-G-BRD-03: Development of a Real-Time Optical Tracking Goggle System (OTGS) for Intracranial Stereotactic Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Mittauer, K; Yan, G; Lu, B; Barraclough, B; Li, J; Liu, C [University of Florida, Gainesville, FL (United States)

2014-06-15

Purpose: Optical tracking systems (OTS) are an acceptable alternative to frame-based stereotactic radiotherapy (SRT). However, current surface-based OTS lack the ability to target exclusively rigid/bony anatomical features. We propose a novel marker-based optical tracking goggle system (OTGS) that provides real-time guidance based on the nose/facial bony anatomy. This ongoing study involves the development and characterization of the OTGS for clinical implementation in intracranial stereotactic radiotherapy. Methods: The OTGS consists of eye goggles, a custom thermoplastic nosepiece, and 6 infrared markers pre-attached to the goggles. A phantom and four healthy volunteers were used to evaluate the calibration/registration accuracy, intrafraction accuracy, interfraction reproducibility, and end-to-end accuracy of the OTGS. The performance of the OTGS was compared with that of the frameless SonArray system and cone-beam computed tomography (CBCT) for volunteer and phantom cases, respectively. The performance of the OTGS with commercial immobilization devices and under treatment conditions (i.e., couch rotation and translation range) was also evaluated. Results: The difference in the calibration/registration accuracy of 24 translations or rotation combinations between CBCT and in-house OTS software was within 0.5 mm/0.4°. The mean intrafraction and interfraction accuracy among the volunteers was 0.004+/−0.4mm with −0.09+/−0.5° (n=6,170) and −0.26+/−0.8mm with 0.15+/0.8° (n=11), respectively. The difference in end-to-end accuracy between the OTGS and CBCT was within 1.3 mm/1.1°. The predetermined marker pattern (1) minimized marker occlusions, (2) allowed for continuous tracking for couch angles +/− 90°, (3) and eliminated individual marker misplacement. The device was feasible with open and half masks for immobilization. Conclusion: Bony anatomical localization eliminated potential errors due to facial hair changes and/or soft tissue deformation. The

Choice probability generating functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

2013-01-01

This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...... probabilities, and every CPGF is consistent with an ARUM. We relate CPGF to multivariate extreme value distributions, and review and extend methods for constructing CPGF for applications. The choice probabilities of any ARUM may be approximated by a cross-nested logit model. The results for ARUM are extended...

Empirical analyses of a choice model that captures ordering among attribute values

DEFF Research Database (Denmark)

Mabit, Stefan Lindhard

2017-01-01

an alternative additionally because it has the highest price. In this paper, we specify a discrete choice model that takes into account the ordering of attribute values across alternatives. This model is used to investigate the effect of attribute value ordering in three case studies related to alternative-fuel...... vehicles, mode choice, and route choice. In our application to choices among alternative-fuel vehicles, we see that especially the price coefficient is sensitive to changes in ordering. The ordering effect is also found in the applications to mode and route choice data where both travel time and cost...

A Common Mechanism Underlying Food Choice and Social Decisions.

Directory of Open Access Journals (Sweden)

Ian Krajbich

2015-10-01

Full Text Available People make numerous decisions every day including perceptual decisions such as walking through a crowd, decisions over primary rewards such as what to eat, and social decisions that require balancing own and others' benefits. The unifying principles behind choices in various domains are, however, still not well understood. Mathematical models that describe choice behavior in specific contexts have provided important insights into the computations that may underlie decision making in the brain. However, a critical and largely unanswered question is whether these models generalize from one choice context to another. Here we show that a model adapted from the perceptual decision-making domain and estimated on choices over food rewards accurately predicts choices and reaction times in four independent sets of subjects making social decisions. The robustness of the model across domains provides behavioral evidence for a common decision-making process in perceptual, primary reward, and social decision making.

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

International Nuclear Information System (INIS)

Nambu, Atsushi; Tominaga, Lichto; Maehata, Yoshiyasu; Sawada, Eiichi; Araki, Tsutomu; Onishi, Hiroshi; Aoki, Shinichi; Koshiishi, Tsuyota; Kuriyama, Kengo; Komiyama, Takafumi; Marino, Kan; Araya, Masayuki; Saito, Ryo

2011-01-01

Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present

Promoting educated consumer choices

DEFF Research Database (Denmark)

Edinger, Wieke Willemijn Huizing

2016-01-01

Contemporary EU food information legislation combines and balances two main consumer interests, i.e., a consumer right to information and the freedom of choice, into one single protective standard: informed choice. Although the recent legislative measures quite openly establish a link between...... informed choice and the rather abstract societal norm of “what is good for the consumer,” this does not justify the conclusion that food information legislation has become overly meddlesome in relation to EU consumers and their choice of food. Rather, there has been a gradual maturing of the EU legislator......’s perception of its task from the mere provision of food information to ensuring educated consumer choices. This development is a logical and necessary consequence of the growing complexity of food choices....

Prospect theory based estimation of drivers' risk attitudes in route choice behaviors.

Science.gov (United States)

Zhou, Lizhen; Zhong, Shiquan; Ma, Shoufeng; Jia, Ning

2014-12-01

This paper applied prospect theory (PT) to describe drivers' route choice behavior under Variable Message Sign (VMS), which presented visual traffic information to assist them to make route choice decisions. A quite rich empirical data from questionnaire and field spot was used to estimate parameters of PT. In order to make the parameters more realistic with drivers' attitudes, they were classified into different types by significant factors influencing their behaviors. Based on the travel time distribution of alternative routes and route choice results from questionnaire, the parameterized value function of each category was figured out, which represented drivers' risk attitudes and choice characteristics. The empirical verification showed that the estimates were acceptable and effective. The result showed drivers' risk attitudes and route choice characteristics could be captured by PT under real-time information shown on VMS. For practical application, once drivers' route choice characteristics and parameters were identified, their route choice behavior under different road conditions could be predicted accurately, which was the basis of traffic guidance measures formulation and implementation for targeted traffic management. Moreover, the heterogeneous risk attitudes among drivers should be considered when releasing traffic information and regulating traffic flow. Copyright © 2014 Elsevier Ltd. All rights reserved.

Airport Choice in Sao Paulo Metropolitan Area: An Application of the Conditional Logit Model

Science.gov (United States)

Moreno, Marcelo Baena; Muller, Carlos

2003-01-01

Using the conditional LOGIT model, this paper addresses the airport choice in the Sao Paulo Metropolitan Area. In this region, Guarulhos International Airport (GRU) and Congonhas Airport (CGH) compete for passengers flying to several domestic destinations. The airport choice is believed to be a result of the tradeoff passengers perform considering airport access characteristics, airline level of service characteristics and passenger experience with the analyzed airports. It was found that access time to the airports better explain the airport choice than access distance, whereas direct flight frequencies gives better explanation to the airport choice than the indirect (connections and stops) and total (direct plus indirect) flight frequencies. Out of 15 tested variables, passenger experience with the analyzed airports was the variable that best explained the airport choice in the region. Model specifications considering 1, 2 or 3 variables were tested. The model specification most adjusted to the observed data considered access time, direct flight frequencies in the travel period (morning or afternoon peak) and passenger experience with the analyzed airports. The influence of these variables was therefore analyzed across market segments according to departure airport and flight duration criteria. The choice of GRU (located neighboring Sao Paulo city) is not well explained by the rationality of access time economy and the increase of the supply of direct flight frequencies, while the choice of CGH (located inside Sao Paulo city) is. Access time was found to be more important to passengers flying shorter distances while direct flight frequencies in the travel period were more significant to those flying longer distances. Keywords: Airport choice, Multiple airport region, Conditional LOGIT model, Access time, Flight frequencies, Passenger experience with the analyzed airports, Transportation planning

Tough Choices or Tough Times: The Report of the New Commission on the Skills of the American Workforce. Revised and Expanded Edition

Science.gov (United States)

Jossey-Bass, An Imprint of Wiley, 2008

2008-01-01

"Tough Choices or Tough Times," the report of the New Commission on the Skills of the American Workforce, shows how the dynamics of the global economy will lead to a steady decline in the American standard of living if this country does not undertake the first thorough overhaul of its education system in a century. This new revised and expanded…

Bilingual Mothers' Language Choice in Child-directed Speech: Continuity and Change

OpenAIRE

De Houwer, Annick; Bornstein, Marc H.

2016-01-01

An important aspect of Family Language Policy in bilingual families is parental language choice. Little is known about the continuity in parental language choice and the factors affecting it. This longitudinal study explores maternal language choice over time. Thirty-one bilingual mothers provided reports of what language(s) they spoke with their children. Mother-child interactions were videotaped when children were pre-verbal (5M), producing words in two languages (20M), and fluent speakers ...

Development and Preliminary Testing of the Food Choice Priorities Survey (FCPS): Assessing the Importance of Multiple Factors on College Students' Food Choices.

Science.gov (United States)

Vilaro, Melissa J; Zhou, Wenjun; Colby, Sarah E; Byrd-Bredbenner, Carol; Riggsbee, Kristin; Olfert, Melissa D; Barnett, Tracey E; Mathews, Anne E

2017-12-01

Understanding factors that influence food choice may help improve diet quality. Factors that commonly affect adults' food choices have been described, but measures that identify and assess food choice factors specific to college students are lacking. This study developed and tested the Food Choice Priorities Survey (FCPS) among college students. Thirty-seven undergraduates participated in two focus groups ( n = 19; 11 in the male-only group, 8 in the female-only group) and interviews ( n = 18) regarding typical influences on food choice. Qualitative data informed the development of survey items with a 5-point Likert-type scale (1 = not important, 5 = extremely important). An expert panel rated FCPS items for clarity, relevance, representativeness, and coverage using a content validity form. To establish test-retest reliability, 109 first-year college students completed the 14-item FCPS at two time points, 0-48 days apart ( M = 13.99, SD = 7.44). Using Cohen's weighted κ for responses within 20 days, 11 items demonstrated moderate agreement and 3 items had substantial agreement. Factor analysis revealed a three-factor structure (9 items). The FCPS is designed for college students and provides a way to determine the factors of greatest importance regarding food choices among this population. From a public health perspective, practical applications include using the FCPS to tailor health communications and behavior change interventions to factors most salient for food choices of college students.

Theory of choice in bandit, information sampling and foraging tasks.

Science.gov (United States)

Averbeck, Bruno B

2015-03-01

Decision making has been studied with a wide array of tasks. Here we examine the theoretical structure of bandit, information sampling and foraging tasks. These tasks move beyond tasks where the choice in the current trial does not affect future expected rewards. We have modeled these tasks using Markov decision processes (MDPs). MDPs provide a general framework for modeling tasks in which decisions affect the information on which future choices will be made. Under the assumption that agents are maximizing expected rewards, MDPs provide normative solutions. We find that all three classes of tasks pose choices among actions which trade-off immediate and future expected rewards. The tasks drive these trade-offs in unique ways, however. For bandit and information sampling tasks, increasing uncertainty or the time horizon shifts value to actions that pay-off in the future. Correspondingly, decreasing uncertainty increases the relative value of actions that pay-off immediately. For foraging tasks the time-horizon plays the dominant role, as choices do not affect future uncertainty in these tasks.

Theory of Visual Attention (TVA) applied to mice in the 5-choice serial reaction time task

DEFF Research Database (Denmark)

Fitzpatrick, C. M.; Caballero-Puntiverio, M.; Gether, U.

2017-01-01

Rationale The 5-choice serial reaction time task (5-CSRTT) is widely used to measure rodent attentional functions. In humans, many attention studies in healthy and clinical populations have used testing based on Bundesen’s Theory of Visual Attention (TVA) to estimate visual processing speeds...... on an individual level. Scopolamine HBr dose-dependently reduced 5-CSRTT attentional performance while also increasing reward collection latency at the highest dose. Upon TVA modelling, scopolamine HBr significantly reduced visual processing speed at both doses, while having less pronounced effects on visual...... modelled using a new three-parameter version of TVA to obtain estimates of visual processing speeds, visual thresholds and motor response baselines in each mouse. Results The parameter estimates for each animal were reliable across sessions, showing that the data were stable enough to support analysis...

Choice Probability Generating Functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel L; Bierlaire, Michel

This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...... probabilities, and every CPGF is consistent with an ARUM. We relate CPGF to multivariate extreme value distributions, and review and extend methods for constructing CPGF for applications....

Multiple-choice pretesting potentiates learning of related information.

Science.gov (United States)

Little, Jeri L; Bjork, Elizabeth Ligon

2016-10-01

Although the testing effect has received a substantial amount of empirical attention, such research has largely focused on the effects of tests given after study. The present research examines the effect of using tests prior to study (i.e., as pretests), focusing particularly on how pretesting influences the subsequent learning of information that is not itself pretested but that is related to the pretested information. In Experiment 1, we found that multiple-choice pretesting was better for the learning of such related information than was cued-recall pretesting or a pre-fact-study control condition. In Experiment 2, we found that the increased learning of non-pretested related information following multiple-choice testing could not be attributed to increased time allocated to that information during subsequent study. Last, in Experiment 3, we showed that the benefits of multiple-choice pretesting over cued-recall pretesting for the learning of related information persist over 48 hours, thus demonstrating the promise of multiple-choice pretesting to potentiate learning in educational contexts. A possible explanation for the observed benefits of multiple-choice pretesting for enhancing the effectiveness with which related nontested information is learned during subsequent study is discussed.

Mate Choice Drives Evolutionary Stability in a Hybrid Complex.

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Miguel Morgado-Santos

Full Text Available Previous studies have shown that assortative mating acts as a driver of speciation by countering hybridization between two populations of the same species (pre-zygotic isolation or through mate choice among the hybrids (hybrid speciation. In both speciation types, assortative mating promotes speciation over a transient hybridization stage. We studied mate choice in a hybrid vertebrate complex, the allopolyploid fish Squalius alburnoides. This complex is composed by several genomotypes connected by an intricate reproductive dynamics. We developed a model that predicts the hybrid complex can persist when females exhibit particular mate choice patterns. Our model is able to reproduce the diversity of population dynamic outcomes found in nature, namely the dominance of the triploids and the dominance of the tetraploids, depending on female mate choice patterns and frequency of the parental species. Experimental mate choice trials showed that females exhibit the preferences predicted by the model. Thus, despite the known role of assortative mating in driving speciation, our findings suggest that certain mate choice patterns can instead hinder speciation and support the persistence of hybrids over time without speciation or extinction.

Rats prefer mutual rewards in a prosocial choice task.

Science.gov (United States)

Hernandez-Lallement, Julen; van Wingerden, Marijn; Marx, Christine; Srejic, Milan; Kalenscher, Tobias

2014-01-01

Pro-sociality, i.e., the preference for outcomes that produce benefits for other individuals, is ubiquitous in humans. Recently, cross-species comparisons of social behavior have offered important new insights into the evolution of pro-sociality. Here, we present a rodent analog of the Pro-social Choice Task that controls strategic components, de-confounds other-regarding choice motives from the animals' natural tendencies to maximize own food access and directly tests the effect of social context on choice allocation. We trained pairs of rats-an actor and a partner rat-in a double T-maze task where actors decided between two alternatives only differing in the reward delivered to the partner. The "own reward" choice yielded a reward only accessible to the actor whereas the "both reward" choice produced an additional reward for a partner (partner condition) or an inanimate toy (toy Condition), located in an adjacent compartment. We found that actors chose "both reward" at levels above chance and more often in the partner than in the toy condition. Moreover, we show that this choice pattern adapts to the current social context and that the observed behavior is stable over time.

Self-choice enhances value in reward-seeking in primates.

Science.gov (United States)

Setogawa, Tsuyoshi; Mizuhiki, Takashi; Matsumoto, Narihisa; Akizawa, Fumika; Shidara, Munetaka

2014-03-01

When an individual chooses one item from two or more alternatives, they compare the values of the expected outcomes. The outcome value can be determined by the associated reward amount, the probability of reward, and the workload required to earn the reward. Rational choice theory states that choices are made to maximize rewards over time, and that the same outcome values lead to an equal likelihood of choices. However, the theory does not distinguish between conditions with the same reward value, even when acquired under different circumstances, and does not always accurately describe real behavior. We have found that allowing a monkey to choose a reward schedule endows the schedule with extra value when compared to performance in an identical schedule that is chosen by another agent (a computer here). This behavior is not consistent with pure rational choice theory. Theoretical analysis using a modified temporal-difference learning model showed an enhanced schedule state value by self-choice. These results suggest that an increased reward value underlies the improved performances by self-choice during reward-seeking behavior. Copyright © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Choice-Induced Preference Change in the Free-Choice Paradigm: A Critical Methodological Review

Directory of Open Access Journals (Sweden)

Keise eIzuma

2013-02-01

Full Text Available Choices not only reflect our preference, but they also affect our behavior. The phenomenon of choice-induced preference change has been of interest to cognitive dissonance researchers in social psychology, and more recently, it has attracted the attention of researchers in economics and neuroscience. Preference modulation after the mere act of making a choice has been repeatedly demonstrated over the last 50 years by an experimental paradigm called the free-choice paradigm. However, in 2010, Chen and Risen pointed out a serious methodological flaw in this paradigm, arguing that evidence for choice-induced preference change is still insufficient. Despite the flaw, studies using the traditional free-choice paradigm continue to be published without addressing the criticism. Here, aiming to draw more attention to this issue, we briefly explain the methodological problem, and then describe simple simulation studies that illustrate how the free-choice paradigm produces a systematic pattern of preference change consistent with cognitive dissonance, even without any change in true preference. Our stimulation also shows how a different level of noise in each phase of the free-choice paradigm independently contributes to the magnitude of artificial preference change. Furthermore, we review ways of addressing the critique and provide a meta-analysis to show the effect size of choice-induced preference change after addressing the critique. Finally, we review and discuss, based on the results of the stimulation studies, how the criticism affects our interpretation of past findings generated from the free-choice paradigm. We conclude that the use of the conventional free-choice paradigm should be avoided in future research and the validity of past findings from studies using this paradigm should be empirically re-established.

Down the Neoliberal Path: The Rise of Free Choice Feminism

OpenAIRE

Ankica Čakardić

2017-01-01

The free choice ideology dictates that any time a woman makes a choice it is an act of feminism. The idea that personal choice presupposes the faraway horizons of freedom and its guarantee, as well as the undoubted potentials of women’s empowerment, makes up the central position of the critique in this essay. Our text is divided into two parts. In the first part of the paper we are going to outline the basic assumptions of neoliberalism, in order to use them as foundations for the argument ab...

Optimal Effort in Consumer Choice : Theory and Experimental Evidence for Binary Choice

NARCIS (Netherlands)

Conlon, B.J.; Dellaert, B.G.C.; van Soest, A.H.O.

2001-01-01

This paper develops a theoretical model of optimal effort in consumer choice.The model extends previous consumer choice models in that the consumer not only chooses a product, but also decides how much effort to apply to a given choice problem.The model yields a unique optimal level of effort, which

Effects of missense mutations in sortase A gene on enzyme activity in Streptococcus mutans.

Science.gov (United States)

Zhuang, P L; Yu, L X; Tao, Y; Zhou, Y; Zhi, Q H; Lin, H C

2016-04-11

Streptococcus mutans (S. mutans) is the major aetiological agent of dental caries, and the transpeptidase Sortase A (SrtA) plays a major role in cariogenicity. The T168G and G470A missense mutations in the srtA gene may be linked to caries susceptibility, as demonstrated in our previous studies. This study aimed to investigate the effects of these missense mutations of the srtA gene on SrtA enzyme activity in S. mutans. The point mutated recombinant S.mutans T168G and G470A sortases were expressed in expression plasmid pET32a. S. mutans UA159 sortase coding gene srtA was used as the template for point mutation. Enzymatic activity was assessed by quantifying increases in the fluorescence intensity generated when a substrate Dabcyl-QALPNTGEE-Edans was cleaved by SrtA. The kinetic constants were calculated based on the curve fit for the Michaelis-Menten equation. SrtA△N40(UA159) and the mutant enzymes, SrtA△N40(D56E) and SrtA△N40(R157H), were expressed and purified. A kinetic analysis showed that the affinity of SrtA△N40(D56E) and SrtA△N40(R157H) remained approximately equal to the affinity of SrtA△N40(UA159), as determined by the Michaelis constant (K m ). However, the catalytic rate constant (k cat ) and catalytic efficiency (k cat /K m ) of SrtA△N40(D56E) were reduced compared with those of SrtA△N40(R157H) and SrtA△N40(UA159), whereas the k cat and k cat /K m values of SrtA△N40(R157H) were slightly lower than those of SrtA△N40(UA159). The findings of this study indicate that the T168G missense mutation of the srtA gene results in a significant reduction in enzymatic activity compared with S. mutans UA159, suggesting that the T168G missense mutation of the srtA gene may be related to low cariogenicity.

Performing a Choice-Narrative

DEFF Research Database (Denmark)

Holmegaard, Henriette Tolstrup

2015-01-01

Students’ science choices have long attracted attention in both public and research. Recently there has been a call for qualitative studies to explore how choices create a sense of fit for individual students. Therefore, this paper aims to study how science students’ choices of higher education...... side articulated as not too predictable, and on the other side appearing realistic and adjusted to the students’ sense of self. Third, the choice-narratives were informed, validated and adjusted in the students’ social network providing the students with a repertoire of viable pathways. The study...... demonstrates how cultural discourses about how a proper choice is made set the scene for the students’ choices. The study raises some concerns for science education. Improving students’ interests in science alone might not lead to increased admission as several interests equally intervene. To attract more...

Modeling duration choice in space–time multi-state supernetworks for individual activity-travel scheduling

NARCIS (Netherlands)

Liao, F.

2016-01-01

Multi-state supernetworks have been advanced recently for modeling individual activity-travel scheduling decisions. The main advantage is that multi-dimensional choice facets are modeled simultaneously within an integral framework, supporting systematic assessments of a large spectrum of policies

Stereotactic radiation therapy for oligometastases or oligorecurrence within mediastinal lymph nodes.

Science.gov (United States)

Wang, Huan-Huan; Zaorsky, Nicholas G; Meng, Mao-Bin; Zeng, Xian-Liang; Deng, Lei; Song, Yong-Chun; Zhuang, Hong-Qing; Li, Feng-Tong; Zhao, Lu-Jun; Yuan, Zhi-Yong; Wang, Ping; Hao, Xi-Shan

2016-04-05

This study evaluated the safety and efficacy of stereotactic radiation therapy (SRT) for the treatment of patients with oligometastases or oligorecurrence within mediastinal lymph nodes (MLNs) originating from different tumors. Between October 2006 and May 2015, patients with MLN oligometastases or oligorecurrence were enrolled and treated with SRT at our hospital. The primary endpoint was MLN local control (LC). Secondary endpoints were time to symptom alleviation, overall survival (OS) after SRT, and toxicity using the Common Terminology Criteria for Adverse Events (CTCAE v4.0). Eighty-five patients with 98 MLN oligometastases or oligorecurrences were treated with SRT. For the entire cohort, the 1-year and 5-year actuarial LC rates were 97% and 77%, respectively. Of 53 symptomatic patients, symptom alleviation was observed in 47 (89%) after a median of 5 days (range, 3-30 days). The median OS was 27.2 months for all patients. For patients with non-small cell lung cancer, univariate and multivariate analyses revealed that a shorter interval between diagnosis of primary tumors and SRT and larger MLN SRT volume were associated with worse OS. CTCAE v4.0 ≥ Grade 3 toxicities occurred in six patients (7%), with Grade 5 in three patients (all with RT history to MLN station 7). SRT is a safe and efficacious treatment modality for patients with oligometastases or oligorecurrence to MLNs originating from different tumors, except for patients who received radiotherapy to MLN station 7. Further investigation is warranted to identify the patients who benefit most from this treatment modality.

Children's food choice process in the home environment. A qualitative descriptive study.

Science.gov (United States)

Holsten, Joanna E; Deatrick, Janet A; Kumanyika, Shiriki; Pinto-Martin, Jennifer; Compher, Charlene W

2012-02-01

This qualitative descriptive study explored children's food choices in the home with particular attention to environmental influences. Semi-structured interviews were conducted with 11- to 14-year-old children (n=47) from one middle school. A data-driven content analysis using selected principles of grounded theory was performed. Children's food choices in the home emerged as a process that involved three interacting components, the child, the parent, and the food, embedded within the context of time. Children's structured activities throughout the day, week, and year provided an overall context for food choices. Parents affected children's food choices through their presence in the home, time pressure and activity prioritization, incorporation of family members' preferences, food preparation effort and skills, and financial and health concerns. Parents created food options through food purchasing and preparation and indirectly affected children's food choices by setting rules, providing information, and modeling behaviors. Children affected parents' decisions by communicating food preferences. For children, important aspects of the food itself included its availability at home and attributes related to taste, preparation, and cost. Children evaluated potential food options based on their hunger level, food preferences, time pressure and activity prioritization, food preparation effort and skills, and expected physical consequences of food. Copyright © 2011 Elsevier Ltd. All rights reserved.

Consumer choice behaviour

DEFF Research Database (Denmark)

Hansen, Flemming; Percy, Larry; Hallum Hansen, Morten

2004-01-01

The paper is concerned with the measurement of emotions and the study of the role ofemotions in consumer choice. Contemporary neurological findings suggest that emotionsmay play a role in its own right, quite different from the way in which they have beenconsidered in traditional consumer choice ...... behaviour theory. A large-scale study including800 respondents, covering 64 brands, provide findings on emotional response tendenciesfor the brands, and relate these to involvement, type of need gratification, purchasingbehaviour, etc.......The paper is concerned with the measurement of emotions and the study of the role ofemotions in consumer choice. Contemporary neurological findings suggest that emotionsmay play a role in its own right, quite different from the way in which they have beenconsidered in traditional consumer choice...

Analyzing multiday route choice behavior of commuters using GPS data

Directory of Open Access Journals (Sweden)

Wenyun Tang

2016-02-01

Full Text Available In this study, accurate global position system and geographic information system data were employed to reveal multiday routes people used and to study multiday route choice behavior for the same origin–destination trips, from home to work. A new way of thinking about route choice modeling is provided in this study. Travelers are classified into three kinds based on the deviation between actual routes and the shortest travel time paths. Based on the classification, a two-stage route choice process is proposed, in which the first step is to classify the travelers and the second one is to model route choice behavior. After analyzing the characteristics of different types of travelers, an artificial neural network was adopted to classify travelers and model route choice behavior. An empirical study using global position systems data collected in Minneapolis–St Paul metropolitan area was carried out. It finds that most travelers follow the same route during commute trips on successive days. And different types of travelers have a significant difference in route choice property. The modeling results indicate that neural network framework can classify travelers and model route choice well.

Application of stress relaxation testing in evaluation of creep strength of a tungsten-alloyed 10% Cr cast steel

International Nuclear Information System (INIS)

Raghavender Rao, G.; Gupta, O.P.; Pradhan, B.

2011-01-01

Uniaxial isothermal stress relaxation tests (SRT) were performed on a tungsten-alloyed 10% Cr cast steel (G-X12Cr Mo W V Nb N 10 1 1) at temperatures of 580, 600 and 620 o C and initial strain levels of 0.2, 0.5 and 0.8%. Inelastic strain rates for different stresses were estimated from the stress versus time data generated from the tests. Conventional creep tests were also conducted on the same material at 580, 600 and 620 o C and at different stress levels. The strain rate data estimated from SRT were compared with minimum creep rates derived from the creep tests; the strain rates estimated from SRT with 0.8% initial strain level are in better agreement than those estimated from SRT with 0.2 and 0.5% initial strain levels. In order to ascertain the technique, stress relaxation behaviour was estimated from creep test data and compared with the stress relaxation curves obtained from SRT at corresponding temperatures. The stress relaxation curves obtained from SRT with 0.8% initial strain level are in good agreement with the stress relaxation curves estimated from the creep tests. It is concluded that the stress relaxation test with initial strain level of 0.8% could be considered as an appropriate short-term test technique for estimation of creep strength of newly developed materials.

Choice Shifts in Groups

OpenAIRE

Kfir Eliaz; Debraj Ray

2004-01-01

The phenomenon of "choice shifts" in group decision-making is fairly ubiquitous in the social psychology literature. Faced with a choice between a ``safe" and ``risky" decision, group members appear to move to one extreme or the other, relative to the choices each member might have made on her own. Both risky and cautious shifts have been identified in different situations. This paper demonstrates that from an individual decision-making perspective, choice shifts may be viewed as a systematic...

Uncertainty in action-value estimation affects both action choice and learning rate of the choice behaviors of rats.

Science.gov (United States)

Funamizu, Akihiro; Ito, Makoto; Doya, Kenji; Kanzaki, Ryohei; Takahashi, Hirokazu

2012-04-01

The estimation of reward outcomes for action candidates is essential for decision making. In this study, we examined whether and how the uncertainty in reward outcome estimation affects the action choice and learning rate. We designed a choice task in which rats selected either the left-poking or right-poking hole and received a reward of a food pellet stochastically. The reward probabilities of the left and right holes were chosen from six settings (high, 100% vs. 66%; mid, 66% vs. 33%; low, 33% vs. 0% for the left vs. right holes, and the opposites) in every 20-549 trials. We used Bayesian Q-learning models to estimate the time course of the probability distribution of action values and tested if they better explain the behaviors of rats than standard Q-learning models that estimate only the mean of action values. Model comparison by cross-validation revealed that a Bayesian Q-learning model with an asymmetric update for reward and non-reward outcomes fit the choice time course of the rats best. In the action-choice equation of the Bayesian Q-learning model, the estimated coefficient for the variance of action value was positive, meaning that rats were uncertainty seeking. Further analysis of the Bayesian Q-learning model suggested that the uncertainty facilitated the effective learning rate. These results suggest that the rats consider uncertainty in action-value estimation and that they have an uncertainty-seeking action policy and uncertainty-dependent modulation of the effective learning rate. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Money Earlier or Later? Simple Heuristics Explain Intertemporal Choices Better than Delay Discounting1

Science.gov (United States)

Marzilli Ericson, Keith M.; White, John Myles; Laibson, David; Cohen, Jonathan D.

2015-01-01

Heuristic models have been proposed for many domains of choice. We compare heuristic models of intertemporal choice, which can account for many of the known intertemporal choice anomalies, to discounting models. We conduct an out-of-sample, cross-validated comparison of intertemporal choice models. Heuristic models outperform traditional utility discounting models, including models of exponential and hyperbolic discounting. The best performing models predict choices by using a weighted average of absolute differences and relative (percentage) differences of the attributes of the goods in a choice set. We conclude that heuristic models explain time-money tradeoff choices in experiments better than utility discounting models. PMID:25911124

Human X-chromosome inactivation pattern distributions fit a model of genetically influenced choice better than models of completely random choice

Science.gov (United States)

Renault, Nisa K E; Pritchett, Sonja M; Howell, Robin E; Greer, Wenda L; Sapienza, Carmen; Ørstavik, Karen Helene; Hamilton, David C

2013-01-01

In eutherian mammals, one X-chromosome in every XX somatic cell is transcriptionally silenced through the process of X-chromosome inactivation (XCI). Females are thus functional mosaics, where some cells express genes from the paternal X, and the others from the maternal X. The relative abundance of the two cell populations (X-inactivation pattern, XIP) can have significant medical implications for some females. In mice, the ‘choice' of which X to inactivate, maternal or paternal, in each cell of the early embryo is genetically influenced. In humans, the timing of XCI choice and whether choice occurs completely randomly or under a genetic influence is debated. Here, we explore these questions by analysing the distribution of XIPs in large populations of normal females. Models were generated to predict XIP distributions resulting from completely random or genetically influenced choice. Each model describes the discrete primary distribution at the onset of XCI, and the continuous secondary distribution accounting for changes to the XIP as a result of development and ageing. Statistical methods are used to compare models with empirical data from Danish and Utah populations. A rigorous data treatment strategy maximises information content and allows for unbiased use of unphased XIP data. The Anderson–Darling goodness-of-fit statistics and likelihood ratio tests indicate that a model of genetically influenced XCI choice better fits the empirical data than models of completely random choice. PMID:23652377

Saccadic reaction times to audiovisual stimuli show effects of oscillatory phase reset.

Directory of Open Access Journals (Sweden)

Adele Diederich

Full Text Available Initiating an eye movement towards a suddenly appearing visual target is faster when an accessory auditory stimulus occurs in close spatiotemporal vicinity. Such facilitation of saccadic reaction time (SRT is well-documented, but the exact neural mechanisms underlying the crossmodal effect remain to be elucidated. From EEG/MEG studies it has been hypothesized that coupled oscillatory activity in primary sensory cortices regulates multisensory processing. Specifically, it is assumed that the phase of an ongoing neural oscillation is shifted due to the occurrence of a sensory stimulus so that, across trials, phase values become highly consistent (phase reset. If one can identify the phase an oscillation is reset to, it is possible to predict when temporal windows of high and low excitability will occur. However, in behavioral experiments the pre-stimulus phase will be different on successive repetitions of the experimental trial, and average performance over many trials will show no signs of the modulation. Here we circumvent this problem by repeatedly presenting an auditory accessory stimulus followed by a visual target stimulus with a temporal delay varied in steps of 2 ms. Performing a discrete time series analysis on SRT as a function of the delay, we provide statistical evidence for the existence of distinct peak spectral components in the power spectrum. These frequencies, although varying across participants, fall within the beta and gamma range (20 to 40 Hz of neural oscillatory activity observed in neurophysiological studies of multisensory integration. Some evidence for high-theta/alpha activity was found as well. Our results are consistent with the phase reset hypothesis and demonstrate that it is amenable to testing by purely psychophysical methods. Thus, any theory of multisensory processes that connects specific brain states with patterns of saccadic responses should be able to account for traces of oscillatory activity in observable

Fuel choice, nuclear energy, climate and carbon

International Nuclear Information System (INIS)

Shpyth, A.

2012-01-01

For the second time since the start of commercial nuclear electricity generation, an accident has the world wondering if uranium will be among the future fuel choices in electricity production. Unfortunate when one considers the low-carbon footprint of this energy option. An accident involving a nuclear power plant, or more appropriately the perceived risks associated with an accident at a nuclear power plant, is but one of the issues that makes the impact assessment process related to nuclear energy projects challenging. Other aspects, including the time scales associated with their siting, licensing, operation and decommissioning, also contribute to the challenge. Strategic environmental assessments for future fuel choices in electricity generation, particularly ones that consider the use of life cycle assessment information, would allow for the effective evaluation of the issues identified above. But more importantly from an impact assessment perspective, provide for a comparative assertion for public disclosure on the environmental impacts of fuel choice. This would provide the public and government decision makers with a more complete view of the role nuclear energy may be able to play in mitigating the climate and carbon impacts of increased electricity production, and place issues of cost, complexity and scale in a more understandable context.

Effect of sludge retention time on the biological performance of anaerobic membrane bioreactors treating corn-to-ethanol thin stillage with high lipid content.

Science.gov (United States)

Dereli, Recep Kaan; van der Zee, Frank P; Heffernan, Barry; Grelot, Aurelie; van Lier, Jules B

2014-02-01

The potential of anaerobic membrane bioreactors (AnMBRs) for the treatment of lipid rich corn-to-ethanol thin stillage was investigated at three different sludge retention times (SRT), i.e. 20, 30 and 50 days. The membrane assisted biomass retention in AnMBRs provided an excellent solution to sludge washout problems reported for the treatment of lipid rich wastewaters by granular sludge bed reactors. The AnMBRs achieved high COD removal efficiencies up to 99% and excellent effluent quality. Although higher organic loading rates (OLRs) up to 8.0 kg COD m(-3) d(-1) could be applied to the reactors operated at shorter SRTs, better biological degradation efficiencies, i.e. up to 83%, was achieved at increased SRTs. Severe long chain fatty acid (LCFA) inhibition was observed at 50 days SRT, possibly caused by the extensive dissolution of LCFA in the reactor broth, inhibiting the methanogenic biomass. Physicochemical mechanisms such as precipitation with divalent cations and adsorption on the sludge played an important role in the occurrence of LCFA removal, conversion, and inhibition. Copyright © 2013 Elsevier Ltd. All rights reserved.

A within-sample investigation of test–retest reliability in choice experiment surveys with real economic incentives

DEFF Research Database (Denmark)

Mørkbak, Morten Raun; Olsen, Søren Bøye

2015-01-01

In this paper, we investigate the level of agreement between respondents' choices in identical choice sets in a test-retest choice experiment for a market good with real economic incentives, thus investigating whether the incentivised CE method can be reliable and stable over time. Besides...... comparing choices, we also test for differences in preferences and error variance when a sample of respondents is given the exact same questionnaire twice, with a time lag of 2 weeks in between. Finally, we examine potential reasons and covariates explaining the level of agreement in choices across the 2...... weeks. Across four different tests, we find very good agreement between the two choice experiments - both with respect to overall choices and with respect to preferences. Furthermore, error variances do not differ significantly between the two surveys. The results also show that the larger the utility...

The Effects of the Previous Outcome on Probabilistic Choice in Rats

Science.gov (United States)

Marshall, Andrew T.; Kirkpatrick, Kimberly

2014-01-01

This study examined the effects of previous outcomes on subsequent choices in a probabilistic-choice task. Twenty-four rats were trained to choose between a certain outcome (1 or 3 pellets) versus an uncertain outcome (3 or 9 pellets), delivered with a probability of .1, .33, .67, and .9 in different phases. Uncertain outcome choices increased with the probability of uncertain food. Additionally, uncertain choices increased with the probability of uncertain food following both certain-choice outcomes and unrewarded uncertain choices. However, following uncertain-choice food outcomes, there was a tendency to choose the uncertain outcome in all cases, indicating that the rats continued to “gamble” after successful uncertain choices, regardless of the overall probability or magnitude of food. A subsequent manipulation, in which the probability of uncertain food varied within each session as a function of the previous uncertain outcome, examined how the previous outcome and probability of uncertain food affected choice in a dynamic environment. Uncertain-choice behavior increased with the probability of uncertain food. The rats exhibited increased sensitivity to probability changes and a greater degree of win–stay/lose–shift behavior than in the static phase. Simulations of two sequential choice models were performed to explore the possible mechanisms of reward value computations. The simulation results supported an exponentially decaying value function that updated as a function of trial (rather than time). These results emphasize the importance of analyzing global and local factors in choice behavior and suggest avenues for the future development of sequential-choice models. PMID:23205915

Using Narratives to Explore Other-Directed Occupational Choice and Academic Success

Science.gov (United States)

Rehfuss, Mark C.; Borges, Nicole J.

2006-01-01

The construct of "other-directed versus self-directed career choice" has existed for quite some time. The current focus of vocational psychologists and counselors has made them question the relevance of this construct for contemporary American society. Many counselors today challenge the assumption that a career choice based on others'…

Producers' Complex Risk Management Choices

NARCIS (Netherlands)

Pennings, J.M.E.; Isengildina, O.; Irwin, S.H.; Garcia, P.; Good, D.L.

2008-01-01

Producers have a wide variety of risk management instruments available, making their choice(s) complex. The way producers deal with this complexity can vary and may influence the impact that the determinants, such as risk aversion, have on their choices. A recently developed choice bracketing

Clofibric acid and gemfibrozil removal in membrane bioreactors.

Science.gov (United States)

Gutierrez-Macias, Tania; Nacheva, Petia Mijaylova

2015-01-01

The removal of two blood lipid regulators, clofibric acid (CLA) and gemfibrozil (GFZ), was evaluated using two identical aerobic membrane bioreactors with 6.5 L effective volume each. Polysulfone ultrafiltration hollow fiber membranes were submerged in the reactors. Different operating conditions were tested varying the organic load (F/M), hydraulic residence time (HRT), biomass concentration measured as total suspended solids in the mixed liquor (MLTSS) and the sludge retention time (SRT). Complete GFZ removal was obtained with F/M of 0.21-0.48 kg COD kgTSS⁻¹ d⁻¹, HRT of 4-10 hours, SRT of 10-32 d and MLTSS of 6-10 g L⁻¹. The GFZ removal can be attributed to biodegradation and there was no accumulation of the compound in the biomass. The CLA removals improved with the SRT and HRT increase and F/M decrease. Average removals of 78-79% were obtained with SRT 16-32 d, F/M of 0.21-0.34 kgCOD kgTSS⁻¹ d⁻¹, HRT of 7-10 hours and MLTSS of 6-10 g L⁻¹. Biodegradation was found to be the main removal pathway.

Egalitarianism in Multi-Choice Games

NARCIS (Netherlands)

Brânzei, R.; Llorca, N.; Sánchez-Soriano, J.; Tijs, S.H.

2007-01-01

In this paper we introduce the equal division core for arbitrary multi-choice games and the constrained egalitarian solution for con- vex multi-choice games, using a multi-choice version of the Dutta-Ray algorithm for traditional convex games. These egalitarian solutions for multi-choice games have

Decoupled choice-driven and stimulus-related activity in parietal neurons may be misrepresented by choice probabilities.

Science.gov (United States)

Zaidel, Adam; DeAngelis, Gregory C; Angelaki, Dora E

2017-09-28

Trial-by-trial correlations between neural responses and choices (choice probabilities) are often interpreted to reflect a causal contribution of neurons to task performance. However, choice probabilities may arise from top-down, rather than bottom-up, signals. We isolated distinct sensory and decision contributions to single-unit activity recorded from the dorsal medial superior temporal (MSTd) and ventral intraparietal (VIP) areas of monkeys during perception of self-motion. Superficially, neurons in both areas show similar tuning curves during task performance. However, tuning in MSTd neurons primarily reflects sensory inputs, whereas choice-related signals dominate tuning in VIP neurons. Importantly, the choice-related activity of VIP neurons is not predictable from their stimulus tuning, and these factors are often confounded in choice probability measurements. This finding was confirmed in a subset of neurons for which stimulus tuning was measured during passive fixation. Our findings reveal decoupled stimulus and choice signals in the VIP area, and challenge our understanding of choice signals in the brain.Choice-related signals in neuronal activity may reflect bottom-up sensory processes, top-down decision-related influences, or a combination of the two. Here the authors report that choice-related activity in VIP neurons is not predictable from their stimulus tuning, and that dominant choice signals can bias the standard metric of choice preference (choice probability).

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

Directory of Open Access Journals (Sweden)

Saito Ryo

2011-10-01

Full Text Available Abstract Background Chest wall injury after stereotactic radiotherapy (SRT for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT, appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT for primary lung cancer Materials and methods A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Results Rib fracture was identified on follow-up CT in 41 patients (23.2%. Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months. Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%, of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Conclusion Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present.

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

Science.gov (United States)

2011-01-01

Background Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer Materials and methods A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Results Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Conclusion Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present. PMID:21995807

A fair range of choice: justifying maximum patient choice in the British National Health Service.

Science.gov (United States)

Wilmot, Stephen

2007-06-01

In this paper I put forward an ethical argument for the provision of extensive patient choice by the British National Health Service. I base this argument on traditional liberal rights to freedom of choice, on a welfare right to health care, and on a view of health as values-based. I argue that choice, to be ethically sustainable on this basis, must be values-based and rational. I also consider whether the British taxpayer may be persuadable with regard to the moral acceptability of patient choice, making use of Rawls' theory of political liberalism in this context. I identify issues that present problems in terms of public acceptance of choice, and also identify a boundary issue with regard to public health choices as against individual choices.

Brain microstructural correlates of visuospatial choice reaction time in children

DEFF Research Database (Denmark)

Madsen, Kathrine Skak; Baaré, William F C; Skimminge, Arnold

2011-01-01

The corticospinal tracts and the basal ganglia continue to develop during childhood and adolescence, and indices of their maturation can be obtained using diffusion-weighted imaging. Here we show that a simple measure of visuomotor function is correlated with diffusion parameters...... anisotropy (FA) in the corticospinal tracts, after controlling for age, gender, and handedness. Mean MD and/or FA were extracted from the right and left corticospinal tracts, putamen, and caudate nuclei. As predicted, faster 5-choice RTs were associated with lower MD in the corticospinal tracts, putamen......, and caudate. MD effects on RT were bilateral in the corticospinal tracts and putamen, whilst right caudate MD was more strongly related to performance than was left caudate MD. Our results suggest a link between motor performance variability in children and diffusivity in the motor system, which may...

Influence of product placement in children's movies on children's snack choices.

Science.gov (United States)

Brown, Callie L; Matherne, Camden E; Bulik, Cynthia M; Howard, Janna B; Ravanbakht, Sophie N; Skinner, Asheley C; Wood, Charles T; Bardone-Cone, Anna M; Brown, Jane D; Perrin, Andrew J; Levine, Cary; Steiner, Michael J; Perrin, Eliana M

2017-07-01

Media exposure affects health, including obesity risk. Children's movies often contain food placements-frequently unhealthy foods. However, it is not known if these cues influence children's food choices or consumption after viewing. We explored whether children's snack choices or consumption differs based on: 1) recent exposure to movies with high versus low product placement of unhealthy foods; and 2) children's weight status. Children ages 9-11 were assigned to watch a high ("Alvin and the Chipmunks," n = 54) or low ("Stuart Little," n = 60) product-placement movie. After viewing, participants selected a snack choice from each of five categories, several of which were specifically featured in "Alvin." Uneaten snacks from each participant were weighed upon completion. Snack choice and amount consumed by movie were compared by t-tests, and differences in snack choices by movie were tested with logistic regression. Participants consumed an average of 800.8 kcal; mean kcal eaten did not vary by movie watched. Participants who watched the high product-placement movie had 3.1 times the odds (95% CI 1.3-7.2) of choosing cheese balls (most featured snack) compared to participants who watched the low product-placement movie. Children who were overweight or obese consumed a mean of 857 kcal (95% CI: 789-925) compared to 783 kcal (95% CI: 742-823, p = 0.09) for children who were underweight or healthy weight. Children's weight status did not significantly affect their choice of snack. Branding and obesogenic messaging in children's movies influenced some choices that children made about snack foods immediately following viewing, especially food with greatest exposure time in the film, but did not affect total calories consumed. Future studies should examine how the accumulation of these messages affects children's long-term food choices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Search predicts and changes patience in intertemporal choice

Science.gov (United States)

Johnson, Eric J.

2017-01-01

Intertemporal choice impacts many important outcomes, such as decisions about health, education, wealth, and the environment. However, the psychological processes underlying decisions involving outcomes at different points in time remain unclear, limiting opportunities to intervene and improve people’s patience. This research examines information-search strategies used during intertemporal choice and their impact on decisions. In experiment 1, we demonstrate that search strategies vary substantially across individuals. We subsequently identify two distinct search strategies across individuals. Comparative searchers, who compare features across options, discount future options less and are more susceptible to acceleration versus delay framing than integrative searchers, who integrate the features of an option. Experiment 2 manipulates search using an unobtrusive method to establish a causal relationship between strategy and choice, randomly assigning participants to conditions promoting either comparative or integrative search. Again, comparative search promotes greater patience than integrative search. Additionally, when participants adopt a comparative search strategy, they also exhibit greater effects of acceleration versus delay framing. Although most participants reported that the manipulation did not change their behavior, promoting comparative search decreased discounting of future rewards substantially and speeded patient choices. These findings highlight the central role that heterogeneity in psychological processes plays in shaping intertemporal choice. Importantly, these results indicate that theories that ignore variability in search strategies may be inadvertently aggregating over different subpopulations that use very different processes. The findings also inform interventions in choice architecture to increase patience and improve consumer welfare. PMID:29078303

Effect of Recycle Sludge on Anaerobic Digestion of Palm Oil Mill Effluent in A Thermophilic Continuous Digester

Science.gov (United States)

Irvan; Trisakti, B.; Tomiuchi, Y.; Harahap, U.; Daimon, H.

2017-06-01

The objective of this research is to maintain short retention time and high degradation of palm oil mill effluent (POME) to biogas by applying recycle sludge. Fresh POME from Rambutan Mill without further treatment was used as feed. Two lab-scale digesters supported from Metawater Co. Ltd. have been applied to treat POME at thermophilic (55°C) condition. Both digesters were operated under intermittent operation mode. Experiments were performed in two methods: with and without recycle sludge. Hydraulic retention time (HRT) of both methods was maintained at 6 days, while sludge retention time (SRT) was maintained at various days. The result showed that by extending SRT in return sludge process where 25% of digested slurry recycled to the digester, improvement of volatile solid (VS) decomposition was obtained around 84% at HRT of 6 days and SRT of 21 days. Then, chemical oxygen demand (COD) removal efficiency could be reached until 85% by using recycle sludge.

The Welfare Effects of Farm Household Activity Choices in Post-War Mozambique

OpenAIRE

Brück, Tilman

2004-01-01

This paper analyses the effects of activity choices on farm household income and consumption in a war-affected developing country. The study uses household survey data from Mozambique and controls for the endogeneity of activity choices with instrumental variables. War-time activity choices (such as subsistence farming) are shown to enhance welfare in the post-war period. Market and social exchange induce only limited welfare gains. Cotton adoption reduces household welfare, which contradicts...

AIRLINE ITINERARY CHOICE IN A DYNAMIC SUPPLY ENVIRONMENT: RESULTS FROM A STATED PREFERENCE SURVEY

Directory of Open Access Journals (Sweden)

Uzi Freund-Feinstei

2017-12-01

Full Text Available This paper investigates the choice of airline itineraries in dynamic settings using a tailored stated preference survey. The paper hypothesizes that airline itinerary choice is not a one-time event, but a continuous process during a certain time frame. Consumers can choose either to purchase an itinerary, deferring choice up to the end of the sales period, or completely declining the purchase. Understanding such consumers’ behavior is specifically relevant to the tourism industry, where firms are extensively utilizing internet websites to offer their products (e.g., airline tickets, hotel rooms to consumers. The paper describes the stated preference survey with real itineraries of various airlines on medium and long-haul routes. Choice sets are composed with dynamic and static variables and socio-economic variables. Questionnaires were distributed electronically among various groups of respondents, yielding a sample of 914 persons. Results show that (i itinerary choice deferring takes place, with differences between tourists and business-travelers, (ii the decision whether to defer choice is affected by dynamically changing variables and by the length of each respondent’s allocated choice period, and (iii the proposed methodology is adequate for investigating choice in dynamic settings and thus indicating its potential for further research in transportation planning and in tourism.

Evaluation of the spline reconstruction technique for PET

Energy Technology Data Exchange (ETDEWEB)

Kastis, George A., E-mail: gkastis@academyofathens.gr; Kyriakopoulou, Dimitra [Research Center of Mathematics, Academy of Athens, Athens 11527 (Greece); Gaitanis, Anastasios [Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens 11527 (Greece); Fernández, Yolanda [Centre d’Imatge Molecular Experimental (CIME), CETIR-ERESA, Barcelona 08950 (Spain); Hutton, Brian F. [Institute of Nuclear Medicine, University College London, London NW1 2BU (United Kingdom); Fokas, Athanasios S. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB30WA (United Kingdom)

2014-04-15

Purpose: The spline reconstruction technique (SRT), based on the analytic formula for the inverse Radon transform, has been presented earlier in the literature. In this study, the authors present an improved formulation and numerical implementation of this algorithm and evaluate it in comparison to filtered backprojection (FBP). Methods: The SRT is based on the numerical evaluation of the Hilbert transform of the sinogram via an approximation in terms of “custom made” cubic splines. By restricting reconstruction only within object pixels and by utilizing certain mathematical symmetries, the authors achieve a reconstruction time comparable to that of FBP. The authors have implemented SRT in STIR and have evaluated this technique using simulated data from a clinical positron emission tomography (PET) system, as well as real data obtained from clinical and preclinical PET scanners. For the simulation studies, the authors have simulated sinograms of a point-source and three digital phantoms. Using these sinograms, the authors have created realizations of Poisson noise at five noise levels. In addition to visual comparisons of the reconstructed images, the authors have determined contrast and bias for different regions of the phantoms as a function of noise level. For the real-data studies, sinograms of an{sup 18}F-FDG injected mouse, a NEMA NU 4-2008 image quality phantom, and a Derenzo phantom have been acquired from a commercial PET system. The authors have determined: (a) coefficient of variations (COV) and contrast from the NEMA phantom, (b) contrast for the various sections of the Derenzo phantom, and (c) line profiles for the Derenzo phantom. Furthermore, the authors have acquired sinograms from a whole-body PET scan of an {sup 18}F-FDG injected cancer patient, using the GE Discovery ST PET/CT system. SRT and FBP reconstructions of the thorax have been visually evaluated. Results: The results indicate an improvement in FWHM and FWTM in both simulated and real

The Impact of Students' Choice of Time of Day for Class Activity and Their Sleep Quality on Academic Performance in Multidisciplinary Distance Education Courses

Science.gov (United States)

Miles, Jessica A.

2014-01-01

The purpose of this research was to identify the impact of students' choice of time of day for class activity and their sleep quality on academic performance in multidisciplinary distance education courses at a southeastern U.S. state college. The research addressed the relationship of other individual student characteristics (i.e., age, gender,…

Evolution of friendship and best friendship choices

NARCIS (Netherlands)

Leenders, RTAJ

1996-01-01

It has been recognized in the literature that the mechanisms driving friendship choices differ when different settings are considered. At the same time, it is likely that different types of friendships are governed by different mechanisms. Employing longitudinal sociometric data from classrooms in

Husbands' return migration and wives' occupational choices

NARCIS (Netherlands)

Mahe, Clotilde

2017-01-01

Exploiting the documented effect of migration on occupational choice upon return to their origin country with data from Egypt, we establish a link between return migration of men and their wives' time use through within-couple occupational interdependence. Seemingly Unrelated Regression model

Putting Health Back Into Health Insurance Choice.

Science.gov (United States)

Atanasov, Pavel; Baker, Tom

2014-08-01

What are the barriers to voluntary take-up of high-deductible plans? We address this question using a large-scale employer survey conducted after an open-enrollment period in which a new high-deductible plan was first introduced. Only 3% of the employees chose this plan, despite the respondents' recognition of its financial advantages. Employees who believed that the high-deductible plan provided access to top physicians in the area were three times more likely to choose it than employees who did not share this belief. A framed field experiment using a similar choice menu showed that displaying additional financial information did not increase high-deductible plan take-up. However, when plans were presented as identical except for the deductible, respondents were highly likely to choose the high-deductible plan, especially in a two-way choice. These results suggest that informing plan choosers about high-deductible plans' health access provisions may affect choice more strongly than focusing on their financial advantages. © The Author(s) 2014.

When good news leads to bad choices.

Science.gov (United States)

McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L; Ludvig, Elliot A

2016-01-01

Pigeons and other animals sometimes deviate from optimal choice behavior when given informative signals for delayed outcomes. For example, when pigeons are given a choice between an alternative that always leads to food after a delay and an alternative that leads to food only half of the time after a delay, preference changes dramatically depending on whether the stimuli during the delays are correlated with (signal) the outcomes or not. With signaled outcomes, pigeons show a much greater preference for the suboptimal alternative than with unsignaled outcomes. Key variables and research findings related to this phenomenon are reviewed, including the effects of durations of the choice and delay periods, probability of reinforcement, and gaps in the signal. We interpret the available evidence as reflecting a preference induced by signals for good news in a context of uncertainty. Other explanations are briefly summarized and compared. © 2016 Society for the Experimental Analysis of Behavior.

Students as First-time Voters: The role of Voter Advice Applications in Self-reflection on Party Choice and Political Identity

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Niels Nørgaard Kristensen

2017-03-01

Full Text Available Purpose: This article analyses what characterises first time voters' self-reflections on party choice as they use voter advice applications. Method: This study is based on interviews of 28 Norwegian students (age 18-20preparing themselves for their first election. Findings: Finding a party to vote for is primarily characterized by a process of matching a party to students' political self, which we see as steps toward a political identity. Practical implications: Teaching politics should allow for students' reflections on self and their political preferences.

WE-B-19A-01: SRT II: Uncertainties in SRT

International Nuclear Information System (INIS)

Dieterich, S; Schlesinger, D; Geneser, S

2014-01-01

SRS delivery has undergone major technical changes in the last decade, transitioning from predominantly frame-based treatment delivery to imageguided, frameless SRS. It is important for medical physicists working in SRS to understand the magnitude and sources of uncertainty involved in delivering SRS treatments for a multitude of technologies (Gamma Knife, CyberKnife, linac-based SRS and protons). Sources of SRS planning and delivery uncertainty include dose calculation, dose fusion, and intra- and inter-fraction motion. Dose calculations for small fields are particularly difficult because of the lack of electronic equilibrium and greater effect of inhomogeneities within and near the PTV. Going frameless introduces greater setup uncertainties that allows for potentially increased intra- and interfraction motion, The increased use of multiple imaging modalities to determine the tumor volume, necessitates (deformable) image and contour fusion, and the resulting uncertainties introduced in the image registration process further contribute to overall treatment planning uncertainties. Each of these uncertainties must be quantified and their impact on treatment delivery accuracy understood. If necessary, the uncertainties may then be accounted for during treatment planning either through techniques to make the uncertainty explicit, or by the appropriate addition of PTV margins. Further complicating matters, the statistics of 1-5 fraction SRS treatments differ from traditional margin recipes relying on Poisson statistics. In this session, we will discuss uncertainties introduced during each step of the SRS treatment planning and delivery process and present margin recipes to appropriately account for such uncertainties. Learning Objectives: To understand the major contributors to the total delivery uncertainty in SRS for Gamma Knife, CyberKnife, and linac-based SRS. Learn the various uncertainties introduced by image fusion, deformable image registration, and contouring variation. Learn a variety of strategies for dealing with uncertainty, including margin recipes and explicit visualization of uncertainty. Understand how the assessment of PTV margins differs from regular fractionation (van Herk recipe) for 1–5 fraction deliveries

Money earlier or later? Simple heuristics explain intertemporal choices better than delay discounting does.

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Ericson, Keith M Marzilli; White, John Myles; Laibson, David; Cohen, Jonathan D

2015-06-01

Heuristic models have been proposed for many domains involving choice. We conducted an out-of-sample, cross-validated comparison of heuristic models of intertemporal choice (which can account for many of the known intertemporal choice anomalies) and discounting models. Heuristic models outperformed traditional utility-discounting models, including models of exponential and hyperbolic discounting. The best-performing models predicted choices by using a weighted average of absolute differences and relative percentage differences of the attributes of the goods in a choice set. We concluded that heuristic models explain time-money trade-off choices in experiments better than do utility-discounting models. © The Author(s) 2015.

Saccadic inhibition can cause the remote distractor effect, but the remote distractor effect may not be a useful concept.

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McIntosh, Robert D; Buonocore, Antimo

2014-05-30

We have suggested that the remote distractor effect (RDE), the elevation of average saccadic reaction time (SRT) induced by a task-irrelevant distractor, may be explained as a statistical consequence of a characteristic reshaping of the SRT distribution known as saccadic inhibition (SI; Buonocore & McIntosh, 2008). In a recent paper, Walker and Benson (2013) argue against this idea and claim that the RDE and SI are partly dissociable. Here, we examine this claim, taking the opportunity to clarify potential ambiguities about how SI affects average SRT, and how the presence of SI can be inferred from SRT distributions.We highlight what we consider to be the most interesting aspects of Walker and Benson’s data, and suggest that a more flexible and nuanced view of SI can account for them. In considering the relation between SI and the RDE, we conclude that the RDE may no longer be a useful concept for eye movement researchers. © 2014 ARVO.

Autism: Too eager to learn? Event related potential findings of increased dependency on intentional learning in a serial reaction time task.

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Zwart, Fenny S; Vissers, Constance Th W M; van der Meij, Roemer; Kessels, Roy P C; Maes, Joseph H R

2017-09-01

It has been suggested that people with autism spectrum disorder (ASD) have an increased tendency to use explicit (or intentional) learning strategies. This altered learning may play a role in the development of the social communication difficulties characterizing ASD. In the current study, we investigated incidental and intentional sequence learning using a Serial Reaction Time (SRT) task in an adult ASD population. Response times and event related potentials (ERP) components (N2b and P3) were assessed as indicators of learning and knowledge. Findings showed that behaviorally, sequence learning and ensuing explicit knowledge were similar in ASD and typically developing (TD) controls. However, ERP findings showed that learning in the TD group was characterized by an enhanced N2b, while learning in the ASD group was characterized by an enhanced P3. These findings suggest that learning in the TD group might be more incidental in nature, whereas learning in the ASD group is more intentional or effortful. Increased intentional learning might serve as a strategy for individuals with ASD to control an overwhelming environment. Although this led to similar behavioral performances on the SRT task, it is very plausible that this intentional learning has adverse effects in more complex social situations, and hence contributes to the social impairments found in ASD. Autism Res 2017, 10: 1533-1543. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Rational Choice Theory and Addiction Behaviour

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Miloš Krstić

2014-12-01

Full Text Available The purpose of this paper is to explore the construct of student satisfaction and analyze its relationship with student loyalty in the context of state and private universities. The rational choice theory assumes that, when deciding whether to consume some goods or not, consumers use analysis in order to estimate the values of individual preference indicators. From this point of view, there are risk and time preferences. The former show aversion to a risk and are expressed through the risk aversion coefficient, while the latter measure the degree of preference for present satisfaction in relation to the same satisfaction in the future. The degree of preference for present satisfaction regarding the same satisfaction in the future is expressed by the time preference rate. Smokers with a low time preference rate and high risk aversion coefficient level can be expected to be successful in cessation. The aim of this paper is to study smokers from the perspective of rational choice theory, in order to detect factors influencing their behavior. The study (investigation found that the significant factors for smokers’ behavior are: gender, age, education, risk aversion coefficient, and the time preference rate. Analysis of smokers’ behavior, with appropriate limits and qualifications, is a well-developed and highly effective tool for exploring and interpreting reality.

Primary radiotherapy of stage IIA/B-IIIB cervical carcinoma. A comparison of continuous versus sequential regimens

International Nuclear Information System (INIS)

Mayer, A.; Nemeskeri, C.; Petnehazi, C.; Varga, S.; Naszaly, A.; Borgulya, G.

2004-01-01

Background: comprehensive literature on cervical cancer demonstrates, even today, the need for optimization of the timing of external-beam radiotherapy (EBRT) and high-dose-rate brachytherapy (HDR-BT) in the treatment of stage IIA/B-IIIB cervical carcinoma. Patients and methods: 210 patients with carcinoma of the cervix were treated in the Municipal Center of Oncoradiology between January 1991 and December 1996 (FIGO IIA: n = 10, FIGO IIB: n = 113, and FIGO IIIB: n = 87). Two regimens were compared: sequential radiation therapy (SRT) with 4 x 8 Gy HDR-BT to point A followed by EBRT, and continuous radiation therapy (CRT) in which 5 x 6 Gy HDR-BT to point A, one session per week, was integrated into the EBRT. A total dose of 68-70 Gy to point A and 52-54 Gy to point B was given in EBRT with SRT, five fractions per week were applied. Four fractions per week were applied in CRT, i.e., no EBRT was performed on the day of HDR-BT. Total doses to points A and B were identical in both regimens. Overall treatment time (OTT) amounted to 56 days for SRT and 35 days for CRT. Median follow-up time was 3.4 (2.5-4.2) years. Results: progression-free 5-year-survival (PFS) was 71% in the CRT and 56% in the SRT group. Nevertheless, this difference was not statistically significant (p = 1.00), and the same was found in a subgroup analysis of the different tumor stages, showing, however, an unequivocal trend. Late bladder and rectal injuries occurred in 13% and 25%, respectively. Late rectal injuries were significantly more frequent with SRT than CRT (35 patients in the SRT and 18 patients in the CRT group; p = 0.037). This was due to the higher doses per fraction of HDR-BT in the SRT group. No difference was found regarding late bladder injuries (p = 0.837). Conclusion: for the patients included in this study, no advantage has been found so far in using CRT, i.e., shortening the OTT by weekly integration of HDR-BT into EBRT. Nevertheless, an obvious trend exists. The dose of 8 Gy per

Tough and easy choices

DEFF Research Database (Denmark)

Olsen, Søren Bøye; Lundhede, Thomas; Jacobsen, Jette Bredahl

2011-01-01

and the best alternative to that. We test this hypothesis using data from two independent Choice Experiments both focusing on nature values. In modelling respondents’ self-reported certainty in choice, we find evidence that the stated level of certainty increases significantly as utility difference in choice......Respondents in Stated Preference studies may be uncertain about their preferences for the good presented to them. Inspired by Wang (J Environ Econ Manag 32:219–232, 1997) we hypothesize that respondents’ stated certainty in choice increases with the utility difference between the alternative chosen...... sets increases. In addition, stated certainty increases with income. Furthermore, there is some evidence that male respondents are inherently more certain in their choices than females, and a learning effect may increase stated certainty. We find evidence of this in the first study where the good...

Rats prefer mutual rewards in a ProSocial Choice Task

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Julen eHernandez-Lallement

2015-01-01

Full Text Available Pro-sociality, i.e. the preference for outcomes that produce benefits for other individuals, is ubiquitous in humans. Recently, cross-species comparisons of social behavior have offered important new insights into the evolution of pro-sociality. Here, we present a rodent analog of the Pro-social Choice Task that controls strategic components, de-confounds other-regarding choice motives from the animals’ natural tendencies to maximize own food access and directly tests the effect of social context on choice allocation. We trained pairs of rats – an actor and a partner rat – in a double T-maze task where actors decided between two alternatives only differing in the reward delivered to the partner. The own reward choice yielded a reward only accessible to the actor whereas the both reward choice produced an additional reward for a partner (partner condition or an inanimate toy (toy Condition, located in an adjacent compartment. We found that actors chose both reward at levels above chance and more often in the partner than in the toy condition. Moreover, we show that this choice pattern adapts to the current social context and that the observed behavior is stable over time.

Reproducibility of an objective four-choice canine vision testing technique that assesses vision at differing light intensities.

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Annear, Matthew J; Gornik, Kara R; Venturi, Francesca L; Hauptman, Joe G; Bartoe, Joshua T; Petersen-Jones, Simon M

2013-09-01

The increasing importance of canine retinal dystrophy models means accurate vision testing is needed. This study was performed to evaluate a four-choice vision testing technique for any difference in outcome measures with repeated evaluations of the same dogs.   Four 11-month-old RPE65-deficient dogs. Vision was evaluated using a previously described four-choice vision testing device. Four evaluations were performed at 2-week intervals. Vision was assessed at six different white light intensities (bright through dim), and each eye was evaluated separately. The ability to select the one of the four exit tunnels that was open at the far end was assessed ('choice of exit') and recorded as correct or incorrect first tunnel choice. 'Time to exit' the device was also recorded. Both outcomes were analyzed for significance using anova. We hypothesized that performance would improve with repeated testing (more correct choices and more rapid time to exit). 'Choice of exit' did not vary significantly between each evaluation (P = 0.12), in contrast 'time to exit' increased significantly (P = 0.012), and showed greater variability in dim light conditions. We found no evidence to support the hypothesis that either measure of outcome worsened with repeated testing; in fact, the 'time to exit' outcome worsened rather than improved. The 'choice of exit' gave consistent results between trials. These outcome data indicate the importance of including a choice-based assessment of vision in addition to measurement of device transit time. © 2012 American College of Veterinary Ophthalmologists.

Roles of Time Hazard in Perceptual Decision Making under High Time Pressure

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Minju Kim

2011-05-01

Full Text Available The drift diffusion model (DDM has been successful in capturing the joint dynamics of accuracy and latency data in various perceptual decision making tasks. We evaluated how well the DDM describes dynamics of perceptual decision when subjects were under a varying degree of time pressure. We collected choice and latency responses from human subjects, who discriminated the size of a thin ring stimulus with a varying degree of uncertainty. The degree of time pressure was manipulated both by giving subjects an explicit instruction of different time limits across sessions (0.7 ∼ 1.2 s and by providing feedback to responses that were made later than those time limits. When fitted to the data of choice and latency, the three major variants of the DDM (with static bounds & gain, with time-varying bounds, and with time-varying gain showed a systematic pattern of latency-dependent prediction errors. Here we propose a new variant of the DDM, which adopts a ‘boundary for time hazard’ on the time axis in addition to the choice boundary on the choice-evidence axis in decision space. Our model did not exhibit the biased pattern of errors and was superior than the other models in goodness of fit to the data.

MPTP-induced executive dysfunction is associated with altered prefrontal serotonergic function.

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Maiti, Panchanan; Gregg, Laura C; McDonald, Michael P

2016-02-01

In Parkinson's disease, cognitive deficits manifest as fronto-striatally-mediated executive dysfunction, with impaired attention, planning, judgment, and impulse control. We examined changes in executive function in mice lesioned with subchronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) using a 3-choice serial reaction-time (SRT) task, which included measures of sustained attention and impulse control. Each trial of the baseline SRT task comprised a pseudo-random pre-cue period ranging from 3 to 8 s, followed by a 1-s cue duration. MPTP impaired all measures of impulsive behavior acutely, but with additional training their performance normalized to saline control levels. When challenged with shorter cue durations, MPTP-lesioned mice had significantly slower reaction times than wild-type mice. When challenged with longer pre-cue times, the MPTP-lesioned mice exhibited a loss of impulse control at the longer durations. In lesioned mice, striatal dopamine was depleted by 54% and the number of tyrosine-hydroxylase-positive neurons in the substantia nigra pars compacta was reduced by 75%. Serotonin (5-HT) was unchanged in the striatum and prefrontal cortex (PFC), but the ratio of 5-hydroxyindolacetic acid (5-HIAA) to 5-HT was significantly reduced in the MPTP group in the PFC. In lesioned mice, prefrontal 5-HIAA/5-HT was significantly correlated with the executive impairments and striatal norepinephrine was associated with slower reaction times. None of the neurochemical measures was significantly associated with behavior in saline-treated controls. Taken together, these results show that prefrontal 5-HT turnover may play a pivotal role in MPTP-induced executive dysfunction. Copyright © 2015 Elsevier B.V. All rights reserved.

High costs of female choice in a lekking lizard.

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Maren N Vitousek

2007-06-01

Full Text Available Although the cost of mate choice is an essential component of the evolution and maintenance of sexual selection, the energetic cost of female choice has not previously been assessed directly. Here we report that females can incur high energetic costs as a result of discriminating among potential mates. We used heart rate biologging to quantify energetic expenditure in lek-mating female Galápagos marine iguanas (Amblyrhynchus cristatus. Receptive females spent 78.9+/-23.2 kJ of energy on mate choice over a 30-day period, which is equivalent to approximately (3/4 of one day's energy budget. Females that spent more time on the territories of high-quality, high-activity males displayed greater energetic expenditure on mate choice, lost more mass, and showed a trend towards producing smaller follicles. Choosy females also appear to face a reduced probability of survival if El Niño conditions occur in the year following breeding. These findings indicate that female choice can carry significant costs, and suggest that the benefits that lek-mating females gain through mating with a preferred male may be higher than previously predicted.

Choice in the repeated-gambles experiment.

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Silberberg, A; Murray, P; Christensen, J; Asano, T

1988-09-01

Humans chose 10 times between two roulette wheels projected on a monitor. During the first trial, the left wheel provided a hypothetical $100 with p = .94, and the right wheel provided $250 with p = .39. A titration procedure adjusted the probability of a $250 win across trials to permit estimation of an indifference point between alternatives. In Experiment 1, intertrial-interval duration (25 vs. 90 s) and whether sessions began with an intertrial interval or a trial were varied in a 2 x 2 design in this risky-choice procedure. Risk aversion (preference for the $100 wheel) increased with intertrial interval but was unaffected by whether sessions began with a trial or an intertrial interval. In Experiment 2, all sessions began with a trial, and subjects were informed that the experiment ended after 10 trials. Intertrial-interval duration had no effect on choice. In Experiment 3, intertrial-interval duration and whether subjects were given $10 or $10,000 before beginning were varied among four groups in a 2 x 2 design. In all other ways, the procedure was unchanged from Experiment 2. Intertrial interval had no effect on choice, but the $10,000 groups showed less risk aversion than the $10 groups. These results can be explained more readily in terms of Kahneman and Tversky's (1984) notion of "framing of the prospect" than in terms of Rachlin, Logue, Gibbon, and Frankel's (1986) behavioral account of risky choice.

Development and implementation of a three-choice serial reaction time task for zebrafish (Danio rerio).

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Parker, Matthew O; Millington, Mollie E; Combe, Fraser J; Brennan, Caroline H

2012-02-01

Zebrafish are an established and widely utilized developmental genetic model system, but limitations in developed behavioral assays have meant that their potential as a model in behavioral neuroscience has yet to be fully realized. Here, we describe the development of a novel operant behavioral assay to examine a variety of aspects of stimulus control in zebrafish using a 3 choice serial reaction time task (3 CSRTT). Fish were briefly exposed to three spatially distinct, but perceptually identical stimuli, presented in a random order after a fixed-time inter-trial interval (ITI). Entries to the correct response aperture either during the stimulus presentation, or within a brief limited hold period following presentation, were reinforced with illumination of the magazine light and delivery of a small food reward. Following training, premature responding was probed with a long-ITI session three times; once at baseline, once following a saline injection and once following an injection of a low dose of amphetamine (AMPH; 0.025 mg/kg). We predicted that if premature responding was related to impulsivity (as in rodents) it would be reduced following the AMPH injection. Results confirmed that zebrafish could learn to perform a complex operant task similar to tasks developed for rodents which are used to probe sustained attention and impulsivity, but the results from the AMPH trials were inconclusive. This study provides the foundations for development and further validation of this species as a model for some aspects of human attentional and impulse control disorders, such as substance abuse disorder. Copyright © 2011 Elsevier B.V. All rights reserved.

Combination Therapy with Zoledronic Acid and Parathyroid Hormone Improves Bone Architecture and Strength following a Clinically-Relevant Dose of Stereotactic Radiation Therapy for the Local Treatment of Canine Osteosarcoma in Athymic Rats.

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Curtis, Ryan C; Custis, James T; Ehrhart, Nicole P; Ehrhart, E J; Condon, Keith W; Gookin, Sara E; Donahue, Seth W

2016-01-01

Clinical studies using definitive-intent stereotactic radiation therapy (SRT) for the local treatment of canine osteosarcoma (OSA) have shown canine patients achieving similar median survival times as the current standard of care (amputation and adjuvant chemotherapy). Despite this, there remains an unacceptable high risk of pathologic fracture following radiation treatment. Zoledronic acid (ZA) and parathyroid hormone (PTH) are therapeutic candidates for decreasing this fracture risk post-irradiation. Due to differing mechanisms, we hypothesized that the combined treatment with ZA and PTH would significantly improve bone healing more than ZA or PTH treatment alone. Using an orthotopic model of canine osteosarcoma in athymic rats, we evaluated bone healing following clinically-relevant doses of radiation therapy (12 Gy x 3 fractions, 36 Gy total). Groups included 36 Gy SRT only, 36 Gy SRT plus ZA, 36 Gy SRT plus ZA and PTH, 36 Gy SRT plus PTH, and 36 Gy SRT plus localized PTH treatment. Our study showed significant increases in bone volume and increased polar moments of inertia (in the distal femoral metaphysis) 8 weeks after radiation in the combined (ZA/PTH) treatment group as compared to radiation treatment alone. Histomorphometric analysis revealed evidence of active mineralization at the study endpoint as well as successful tumor-cell kill across all treatment groups. This work provides further evidence for the expanding potential indications for ZA and PTH therapy, including post-irradiated bone disease due to osteosarcoma.

Combination Therapy with Zoledronic Acid and Parathyroid Hormone Improves Bone Architecture and Strength following a Clinically-Relevant Dose of Stereotactic Radiation Therapy for the Local Treatment of Canine Osteosarcoma in Athymic Rats.

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Ryan C Curtis

Full Text Available Clinical studies using definitive-intent stereotactic radiation therapy (SRT for the local treatment of canine osteosarcoma (OSA have shown canine patients achieving similar median survival times as the current standard of care (amputation and adjuvant chemotherapy. Despite this, there remains an unacceptable high risk of pathologic fracture following radiation treatment. Zoledronic acid (ZA and parathyroid hormone (PTH are therapeutic candidates for decreasing this fracture risk post-irradiation. Due to differing mechanisms, we hypothesized that the combined treatment with ZA and PTH would significantly improve bone healing more than ZA or PTH treatment alone. Using an orthotopic model of canine osteosarcoma in athymic rats, we evaluated bone healing following clinically-relevant doses of radiation therapy (12 Gy x 3 fractions, 36 Gy total. Groups included 36 Gy SRT only, 36 Gy SRT plus ZA, 36 Gy SRT plus ZA and PTH, 36 Gy SRT plus PTH, and 36 Gy SRT plus localized PTH treatment. Our study showed significant increases in bone volume and increased polar moments of inertia (in the distal femoral metaphysis 8 weeks after radiation in the combined (ZA/PTH treatment group as compared to radiation treatment alone. Histomorphometric analysis revealed evidence of active mineralization at the study endpoint as well as successful tumor-cell kill across all treatment groups. This work provides further evidence for the expanding potential indications for ZA and PTH therapy, including post-irradiated bone disease due to osteosarcoma.

Environmental enrichment choices of shelter cats.

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Ellis, J J; Stryhn, H; Spears, J; Cockram, M S

2017-08-01

Choices made by cats between different types of environmental enrichment may help shelters to prioritize how to most effectively enrich cat housing, especially when limited by space or funds. This study investigates the environmental enrichment use of cats in a choice test. Twenty-six shelter cats were kept singularly in choice chambers for 10days. Each chamber had a central area and four centrally-linked compartments containing different types of environmental enrichment: 1) an empty control, 2) a prey-simulating toy, 3) a perching opportunity, and 4) a hiding opportunity. Cat movement between compartments was quantitatively recorded using a data-logger. Enriched compartments were visited significantly more frequently during the light period than during the dark period. Cats spent a significantly greater percentage of time in the hiding compartment (median=55%, IQR=46) than in the toy compartment (median=2%, IQR=9), or in the empty control compartment (median=4%, IQR=4). These results provide additional evidence to support the value of a hiding box to cats housed in a novel environment, in that they choose hiding relative to other types of environmental enrichment. Copyright © 2017 Elsevier B.V. All rights reserved.

Paradoxical choice in rats: Subjective valuation and mechanism of choice.

Science.gov (United States)

Ojeda, Andrés; Murphy, Robin A; Kacelnik, Alex

2018-07-01

Decision-makers benefit from information only when they can use it to guide behavior. However, recent experiments found that pigeons and starlings value information that they cannot use. Here we show that this paradox is also present in rats, and explore the underlying decision process. Subjects chose between two options that delivered food probabilistically after a fixed delay. In one option ("info"), outcomes (food/no-food) were signaled immediately after choice, whereas in the alternative ("non-info") the outcome was uncertain until the delay lapsed. Rats sacrificed up to 20% potential rewards by preferring the info option, but reversed preference when the cost was 60%. This reversal contrasts with the results found with pigeons and starlings and may reflect species' differences worth of further investigation. Results are consistent with predictions of the Sequential Choice Model (SCM), that proposes that choices are driven by the mechanisms that control action in sequential encounters. As expected from the SCM, latencies to respond in single-option trials predicted preferences in choice trials, and latencies in choice trials were the same or shorter than in single-option trials. We argue that the congruence of results in distant vertebrates probably reflects evolved adaptations to shared fundamental challenges in nature, and that the apparently paradoxical overvaluing of information is not sub-optimal as has been claimed, even though its functional significance is not yet understood. Copyright © 2018 Elsevier B.V. All rights reserved.

Search predicts and changes patience in intertemporal choice.

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Reeck, Crystal; Wall, Daniel; Johnson, Eric J

2017-11-07

Intertemporal choice impacts many important outcomes, such as decisions about health, education, wealth, and the environment. However, the psychological processes underlying decisions involving outcomes at different points in time remain unclear, limiting opportunities to intervene and improve people's patience. This research examines information-search strategies used during intertemporal choice and their impact on decisions. In experiment 1, we demonstrate that search strategies vary substantially across individuals. We subsequently identify two distinct search strategies across individuals. Comparative searchers, who compare features across options, discount future options less and are more susceptible to acceleration versus delay framing than integrative searchers, who integrate the features of an option. Experiment 2 manipulates search using an unobtrusive method to establish a causal relationship between strategy and choice, randomly assigning participants to conditions promoting either comparative or integrative search. Again, comparative search promotes greater patience than integrative search. Additionally, when participants adopt a comparative search strategy, they also exhibit greater effects of acceleration versus delay framing. Although most participants reported that the manipulation did not change their behavior, promoting comparative search decreased discounting of future rewards substantially and speeded patient choices. These findings highlight the central role that heterogeneity in psychological processes plays in shaping intertemporal choice. Importantly, these results indicate that theories that ignore variability in search strategies may be inadvertently aggregating over different subpopulations that use very different processes. The findings also inform interventions in choice architecture to increase patience and improve consumer welfare. Copyright © 2017 the Author(s). Published by PNAS.

The effects of acute bout of cycling on auditory & visual reaction times.

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Ashnagar, Zinat; Shadmehr, Azadeh; Jalaei, Shohreh

2015-04-01

The purpose of this study was to investigate the effects of an acute bout of cycling exercise on auditory choice reaction time, visual choice reaction time, auditory complex choice reaction time and visual complex choice reaction time. 29 subjects were randomly divided into experimental and control groups. The subjects of the experimental group carried out a single bout of submaximal cycling exercise. The auditory choice reaction time, visual choice reaction time, auditory complex choice reaction time and visual complex choice reaction times were measured before and after the exercise session. The reaction time tests were taken from the subjects by using Speed Anticipation and Reaction Tester (SART) software. In the control group, the reaction time tests were performed by the subjects with an interval of 30 min. In the experimental group, the percentage changes of mean auditory choice and complex choice reaction time values were significantly decreased in comparison with the control group (P visual choice and complex choice reaction times were decreased after the exercise, the changes were not significant (P > 0.05). An acute bout of cycling exercise improved the speed of auditory and visual reaction times in healthy young females. However, these positive changes were significantly observed only in the auditory reaction time tests in comparison with the control group. Copyright © 2014 Elsevier Ltd. All rights reserved.

Age-related slowing of response selection and production in a visual choice reaction time task

Directory of Open Access Journals (Sweden)

David L Woods

2015-04-01

Full Text Available Aging is associated with delayed processing in choice reaction time (CRT tasks, but the processing stages most impacted by aging have not been clearly identified. Here, we analyzed CRT latencies in a computerized serial visual feature-conjunction task. Participants responded to a target letter (probability 40% by pressing one mouse button, and responded to distractor letters differing either in color, shape, or both features from the target (probabilities 20% each, by pressing the other mouse button. Stimuli were presented randomly to the left and right visual fields and stimulus onset asynchronies (SOAs were adaptively reduced following correct responses using a staircase procedure. In Experiment 1, we tested 1466 participants who ranged in age from 18 to 65 years. CRT latencies increased significantly with age (r = 0.47, 2.80 ms/year. Central processing time (CPT, isolated by subtracting simple reaction times (obtained in a companion experiment performed on the same day from CRT latencies, accounted for more than 80% of age-related CRT slowing, with most of the remaining increase in latency due to slowed motor responses. Participants were faster and more accurate when the stimulus location was spatially compatible with the mouse button used for responding, and this effect increased slightly with age. Participants took longer to respond to distractors with target color or shape than to distractors with no target features. However, the additional time needed to discriminate the more target-like distractors did not increase with age. In Experiment 2, we replicated the findings of Experiment 1 in a second population of 178 participants (ages 18-82 years. CRT latencies did not differ significantly in the two experiments, and similar effects of age, distractor similarity, and stimulus-response spatial compatibility were found. The results suggest that the age-related slowing in visual CRT latencies is largely due to delays in response selection and

Vector-model-supported optimization in volumetric-modulated arc stereotactic radiotherapy planning for brain metastasis

International Nuclear Information System (INIS)

Liu, Eva Sau Fan; Wu, Vincent Wing Cheung; Harris, Benjamin; Foote, Matthew; Lehman, Margot; Chan, Lawrence Wing Chi

2017-01-01

Long planning time in volumetric-modulated arc stereotactic radiotherapy (VMA-SRT) cases can limit its clinical efficiency and use. A vector model could retrieve previously successful radiotherapy cases that share various common anatomic features with the current case. The prsent study aimed to develop a vector model that could reduce planning time by applying the optimization parameters from those retrieved reference cases. Thirty-six VMA-SRT cases of brain metastasis (gender, male [n = 23], female [n = 13]; age range, 32 to 81 years old) were collected and used as a reference database. Another 10 VMA-SRT cases were planned with both conventional optimization and vector-model-supported optimization, following the oncologists' clinical dose prescriptions. Planning time and plan quality measures were compared using the 2-sided paired Wilcoxon signed rank test with a significance level of 0.05, with positive false discovery rate (pFDR) of less than 0.05. With vector-model-supported optimization, there was a significant reduction in the median planning time, a 40% reduction from 3.7 to 2.2 hours (p = 0.002, pFDR = 0.032), and for the number of iterations, a 30% reduction from 8.5 to 6.0 (p = 0.006, pFDR = 0.047). The quality of plans from both approaches was comparable. From these preliminary results, vector-model-supported optimization can expedite the optimization of VMA-SRT for brain metastasis while maintaining plan quality.

Vector-model-supported optimization in volumetric-modulated arc stereotactic radiotherapy planning for brain metastasis

Energy Technology Data Exchange (ETDEWEB)

Liu, Eva Sau Fan [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Wu, Vincent Wing Cheung [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong); Harris, Benjamin [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); Foote, Matthew; Lehman, Margot [Department of Radiation Oncology, Princess Alexandra Hospital, Brisbane (Australia); School of Medicine, University of Queensland (Australia); Chan, Lawrence Wing Chi, E-mail: wing.chi.chan@polyu.edu.hk [Department of Health Technology and Informatics, The Hong Kong Polytechnic University (Hong Kong)

2017-07-01

Long planning time in volumetric-modulated arc stereotactic radiotherapy (VMA-SRT) cases can limit its clinical efficiency and use. A vector model could retrieve previously successful radiotherapy cases that share various common anatomic features with the current case. The prsent study aimed to develop a vector model that could reduce planning time by applying the optimization parameters from those retrieved reference cases. Thirty-six VMA-SRT cases of brain metastasis (gender, male [n = 23], female [n = 13]; age range, 32 to 81 years old) were collected and used as a reference database. Another 10 VMA-SRT cases were planned with both conventional optimization and vector-model-supported optimization, following the oncologists' clinical dose prescriptions. Planning time and plan quality measures were compared using the 2-sided paired Wilcoxon signed rank test with a significance level of 0.05, with positive false discovery rate (pFDR) of less than 0.05. With vector-model-supported optimization, there was a significant reduction in the median planning time, a 40% reduction from 3.7 to 2.2 hours (p = 0.002, pFDR = 0.032), and for the number of iterations, a 30% reduction from 8.5 to 6.0 (p = 0.006, pFDR = 0.047). The quality of plans from both approaches was comparable. From these preliminary results, vector-model-supported optimization can expedite the optimization of VMA-SRT for brain metastasis while maintaining plan quality.

Sample selection and taste correlation in discrete choice transport modelling

DEFF Research Database (Denmark)

Mabit, Stefan Lindhard

2008-01-01

explain counterintuitive results in value of travel time estimation. However, the results also point at the difficulty of finding suitable instruments for the selection mechanism. Taste heterogeneity is another important aspect of discrete choice modelling. Mixed logit models are designed to capture...... the question for a broader class of models. It is shown that the original result may be somewhat generalised. Another question investigated is whether mode choice operates as a self-selection mechanism in the estimation of the value of travel time. The results show that self-selection can at least partly...... of taste correlation in willingness-to-pay estimation are presented. The first contribution addresses how to incorporate taste correlation in the estimation of the value of travel time for public transport. Given a limited dataset the approach taken is to use theory on the value of travel time as guidance...

Specific Sirt1 Activator-mediated Improvement in Glucose Homeostasis Requires Sirt1-Independent Activation of AMPK

Directory of Open Access Journals (Sweden)

Sung-Jun Park

2017-04-01

Full Text Available The specific Sirt1 activator SRT1720 increases mitochondrial function in skeletal muscle, presumably by activating Sirt1. However, Sirt1 gain of function does not increase mitochondrial function, which raises a question about the central role of Sirt1 in SRT1720 action. Moreover, it is believed that the metabolic effects of SRT1720 occur independently of AMP-activated protein kinase (AMPK, an important metabolic regulator that increases mitochondrial function. Here, we show that SRT1720 activates AMPK in a Sirt1-independent manner and SRT1720 activates AMPK by inhibiting a cAMP degrading phosphodiesterase (PDE in a competitive manner. Inhibiting the cAMP effector protein Epac prevents SRT1720 from activating AMPK or Sirt1 in myotubes. Moreover, SRT1720 does not increase mitochondrial function or improve glucose tolerance in AMPKα2 knockout mice. Interestingly, weight loss induced by SRT1720 is not sufficient to improve glucose tolerance. Therefore, contrary to current belief, the metabolic effects produced by SRT1720 require AMPK, which can be activated independently of Sirt1.

Optimization of an A(2)/O process for tetracycline removal via response surface methodology coupled with a Box-Behnken design.

Science.gov (United States)

Qi, Fang-Fang; Huang, Man-Hong; Zheng, Yu; Xu, Qi

2015-01-01

Response surface methodology (RSM) was used to optimize the operating conditions of an anaerobic-anoxic-oxic (A(2)/O) process by maximizing the removal efficiency of tetracycline (TC). Solid retention time (SRT), hydraulic retention time (HRT) and initial TC concentration (CTC, in) were selected as independent variables for incorporation in the Box-Behnken design. The results showed SRT and CTC, in were more significant parameters than HRT for the removal efficiency of TC. TC could be completely removed under the optimal conditions of an SRT of 15.5 days, an HRT of 9.9 h and a CTC, in of 283.3 μg L(-1). TC removal efficiencies of 99% and 96% were attained for synthetic and real wastewater, respectively, under the optimal conditions. This indicated the constructed model was validated and reliable for optimizing the A(2)/O process for TC removal.

Choice, changeover, and travel

OpenAIRE

Baum, William M.

1982-01-01

Since foraging in nature can be viewed as instrumental behavior, choice between sources of food, known as “patches,” can be viewed as choice between instrumental response alternatives. Whereas the travel required to change alternatives deters changeover in nature, the changeover delay (COD) usually deters changeover in the laboratory. In this experiment, pigeons were exposed to laboratory choice situations, concurrent variable-interval schedules, that were standard except for the introduction...

THE MULTIPLE CHOICE PROBLEM WITH INTERACTIONS BETWEEN CRITERIA

Directory of Open Access Journals (Sweden)

Luiz Flavio Autran Monteiro Gomes

2015-12-01

Full Text Available ABSTRACT An important problem in Multi-Criteria Decision Analysis arises when one must select at least two alternatives at the same time. This can be denoted as a multiple choice problem. In other words, instead of evaluating each of the alternatives separately, they must be combined into groups of n alternatives, where n = 2. When the multiple choice problem must be solved under multiple criteria, the result is a multi-criteria, multiple choice problem. In this paper, it is shown through examples how this problemcan be tackled on a bipolar scale. The Choquet integral is used in this paper to take care of interactions between criteria. A numerical application example is conducted using data from SEBRAE-RJ, a non-profit private organization that has the mission of promoting competitiveness, sustainable developmentand entrepreneurship in the state of Rio de Janeiro, Brazil. The paper closes with suggestions for future research.

Choice probability generating functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

2010-01-01

This paper establishes that every random utility discrete choice model (RUM) has a representation that can be characterized by a choice-probability generating function (CPGF) with specific properties, and that every function with these specific properties is consistent with a RUM. The choice...... probabilities from the RUM are obtained from the gradient of the CPGF. Mixtures of RUM are characterized by logarithmic mixtures of their associated CPGF. The paper relates CPGF to multivariate extreme value distributions, and reviews and extends methods for constructing generating functions for applications....... The choice probabilities of any ARUM may be approximated by a cross-nested logit model. The results for ARUM are extended to competing risk survival models....

Mass and Energy Balances of Dry Thermophilic Anaerobic Digestion Treating Swine Manure Mixed with Rice Straw.

Science.gov (United States)

Zhou, Sheng; Zhang, Jining; Zou, Guoyan; Riya, Shohei; Hosomi, Masaaki

2015-01-01

To evaluate the feasibility of swine manure treatment by a proposed Dry Thermophilic Anaerobic Digestion (DT-AD) system, we evaluated the methane yield of swine manure treated using a DT-AD method with rice straw under different C/N ratios and solid retention time (SRT) and calculated the mass and energy balances when the DT-AD system is used for swine manure treatment from a model farm with 1000 pigs and the digested residue is used for forage rice production. A traditional swine manure treatment Oxidation Ditch system was used as the study control. The results suggest that methane yield using the proposed DT-AD system increased with a higher C/N ratio and shorter SRT. Correspondently, for the DT-AD system running with SRT of 80 days, the net energy yields for all treatments were negative, due to low biogas production and high heat loss of digestion tank. However, the biogas yield increased when the SRT was shortened to 40 days, and the generated energy was greater than consumed energy when C/N ratio was 20 : 1 and 30 : 1. The results suggest that with the correct optimization of C/N ratio and SRT, the proposed DT-AD system, followed by using digestate for forage rice production, can attain energy self-sufficiency.

Anticipation and choice heuristics in the dynamic consumption of pain relief.

Science.gov (United States)

Story, Giles W; Vlaev, Ivo; Dayan, Peter; Seymour, Ben; Darzi, Ara; Dolan, Raymond J

2015-03-01

Humans frequently need to allocate resources across multiple time-steps. Economic theory proposes that subjects do so according to a stable set of intertemporal preferences, but the computational demands of such decisions encourage the use of formally less competent heuristics. Few empirical studies have examined dynamic resource allocation decisions systematically. Here we conducted an experiment involving the dynamic consumption over approximately 15 minutes of a limited budget of relief from moderately painful stimuli. We had previously elicited the participants' time preferences for the same painful stimuli in one-off choices, allowing us to assess self-consistency. Participants exhibited three characteristic behaviors: saving relief until the end, spreading relief across time, and early spending, of which the last was markedly less prominent. The likelihood that behavior was heuristic rather than normative is suggested by the weak correspondence between one-off and dynamic choices. We show that the consumption choices are consistent with a combination of simple heuristics involving early-spending, spreading or saving of relief until the end, with subjects predominantly exhibiting the last two.

Anticipation and Choice Heuristics in the Dynamic Consumption of Pain Relief

Science.gov (United States)

Story, Giles W.; Vlaev, Ivo; Dayan, Peter; Seymour, Ben; Darzi, Ara; Dolan, Raymond J.

2015-01-01

Humans frequently need to allocate resources across multiple time-steps. Economic theory proposes that subjects do so according to a stable set of intertemporal preferences, but the computational demands of such decisions encourage the use of formally less competent heuristics. Few empirical studies have examined dynamic resource allocation decisions systematically. Here we conducted an experiment involving the dynamic consumption over approximately 15 minutes of a limited budget of relief from moderately painful stimuli. We had previously elicited the participants’ time preferences for the same painful stimuli in one-off choices, allowing us to assess self-consistency. Participants exhibited three characteristic behaviors: saving relief until the end, spreading relief across time, and early spending, of which the last was markedly less prominent. The likelihood that behavior was heuristic rather than normative is suggested by the weak correspondence between one-off and dynamic choices. We show that the consumption choices are consistent with a combination of simple heuristics involving early-spending, spreading or saving of relief until the end, with subjects predominantly exhibiting the last two. PMID:25793302

Determinants of Awareness, Consideration, and Choice Set Size in University Choice.

Science.gov (United States)

Dawes, Philip L.; Brown, Jennifer

2002-01-01

Developed and tested a model of students' university "brand" choice using five individual-level variables (ethnic group, age, gender, number of parents going to university, and academic ability) and one situational variable (duration of search) to explain variation in the sizes of awareness, consideration, and choice decision sets. (EV)

Patient factors in referral choice for total joint replacement surgery.

Science.gov (United States)

Conner-Spady, Barbara L; Marshall, Deborah A; Bohm, Eric; Dunbar, Michael J; Loucks, Lynda; Hennigar, Allan W; Frank, Cy; Noseworthy, Tom W

2014-04-01

Although the option of next available surgeon can be found on surgeon referral forms for total joint replacement surgery, its selection varies across surgical practices. Objectives are to assess the determinants of (a) a patient's request for a particular surgeon; and (b) the actual referral to a specific versus the next available surgeon. Questionnaires were mailed to 306 consecutive patients referred to orthopedic surgeons. We assessed quality of life (Oxford Hip and Knee scores, Short Form-12, EuroQol 5D, Pain Visual Analogue Scale), referral experience, and the importance of surgeon choice, surgeon reputation, and wait time. We used logistic regression to build models for the 2 objectives. We obtained 176 respondents (response rate, 58%), 60% female, 65% knee patients, mean age of 65 years, with no significant differences between responders versus nonresponders. Forty-three percent requested a particular surgeon. Seventy-one percent were referred to a specific surgeon. Patients who rated surgeon choice as very/extremely important [adjusted odds ratio (OR), 6.54; 95% confidence interval (CI), 2.57-16.64] and with household incomes of $90,000+ versus <$30,000 (OR, 5.74; 95% CI, 1.56-21.03) were more likely to request a particular surgeon. Hip patients (OR, 3.03; 95% CI, 1.18-7.78), better Physical Component Summary-12 (OR, 1.29; 95% CI, 1.02-1.63), and patients who rated surgeon choice as very/extremely important (OR, 3.88; 95% CI, 1.56-9.70) were more likely to be referred to a specific surgeon. Most patients want some choice in the referral decision. Providing sufficient information is important, so that patients are aware of their choices and can make an informed choice. Some patients prefer a particular surgeon despite longer wait times.

Market timing and the debt-equity choice

NARCIS (Netherlands)

Elliot, W.B.; Koeter-Kant, J.; Warr, R.S.

2008-01-01

We test the market timing theory of capital structure using an earnings-based valuation model that allows us to separate equity mispricing from growth options and time-varying adverse selection; thus avoiding the multiple interpretations of book-to-market ratio. We find that equity market mispricing

The 2015 hospital treatment choice reform in Norway: Continuity or change?

Science.gov (United States)

Ringard, Ånen; Saunes, Ingrid Sperre; Sagan, Anna

2016-04-01

In several European countries, including Norway, polices to increase patient choice of hospital provider have remained high on the political agenda. The main reason behind the interest in hospital choice reforms in Norway has been the belief that increasing choice can remedy the persistent problem of long waiting times for elective hospital care. Prior to the 2013 General Election, the Conservative Party campaigned in favour of a new choice reform: "the treatment choice reform". This article describes the background and process leading up to introduction of the reform in the autumn of 2015. It also provides a description of the content and discusses possible implications of the reform for patients, providers and government bodies. In sum, the reform contains elements of both continuity and change. The main novelty of the reform lies in the increased role of private for-profit healthcare providers. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Radiobiology of hypofractionated stereotactic radiotherapy: what are the optimal fractionation schedules?

International Nuclear Information System (INIS)

Shibamoto, Yuta; Miyakawa, Akifumi; Otsuka, Shinya; Iwata, Hiromitsu

2016-01-01

In hypofractionated stereotactic radiotherapy (SRT), high doses per fraction are usually used and the dose delivery pattern is different from that of conventional radiation. The daily dose is usually given intermittently over a longer time compared with conventional radiotherapy. During prolonged radiation delivery, sublethal damage repair takes place, leading to the decreased effect of radiation. In in vivo tumors, however, this decrease in effect may be counterbalanced by rapid reoxygenation. Another issue related to hypofractionated SRT is the mathematical model for dose evaluation and conversion. The linear–quadratic (LQ) model and biologically effective dose (BED) have been suggested to be incorrect when used for hypofractionation. The LQ model overestimates the effect of high fractional doses of radiation. BED is particularly incorrect when used for tumor responses in vivo, since it does not take reoxygenation into account. Correction of the errors, estimated at 5–20%, associated with the use of BED is necessary when it is used for SRT. High fractional doses have been reported to exhibit effects against tumor vasculature and enhance host immunity, leading to increased antitumor effects. This may be an interesting topic that should be further investigated. Radioresistance of hypoxic tumor cells is more problematic in hypofractionated SRT, so trials of hypoxia-targeted agents are encouraged in the future. In this review, the radiobiological characteristics of hypofractionated SRT are summarized, and based on the considerations, we would like to recommend 60 Gy in eight fractions delivered three times a week for lung tumors larger than 2 cm in diameter

Mindful eating reduces impulsive food choice in adolescents and adults.

Science.gov (United States)

Hendrickson, Kelsie L; Rasmussen, Erin B

2017-03-01

The present study tested the extent to which age and obesity predicted impulsive choices for food and monetary outcomes and tested how a brief mindful-eating training would alter delay discounting for food and money choices compared with control groups. First, 172 adolescents (M age = 13.13 years) and 176 (M age = 23.33 years) adults completed the Food Choice Questionnaire (FCQ) and Monetary Choice Questionnaire (MCQ) as measures of food and money delay discounting, respectively. Then, participants returned to the lab and were randomly assigned to complete a brief mindful-eating training, watch a DVD on nutrition, or serve as a control. Participants completed the FCQ and MCQ again as a postmanipulation measure. Participants with high percent body fat (PBF) were more impulsive for food than those with low PBF. Adults with high PBF were also more impulsive for money compared with adults with low PBF; no PBF-related differences were found for adolescents. Participants in the mindful-eating group exhibited more self-controlled choices for food, but not for money. The control conditions did not exhibit changes. The study suggests that individuals with high PBF make more impulsive food choices relative to those with low PBF, which could increase the risk of obesity over time. It also is the first to demonstrate shifts in choice patterns for food and money using a brief mindful-eating training with adolescents. Mindful eating is a beneficial strategy to reduce impulsive food choice, at least temporarily, that may impede weight gain. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Development of real-time tumor tracking system for stereotactic radiotherapy

International Nuclear Information System (INIS)

Yamanaka, Seiji; Sasagawa, Tsuyoshi; Uno, Yukimichi

2011-01-01

We are now developing the real-time tumor tracking system for stereotactic radiotherapy (SRT) to provide precise information on the location of a tumor and to reduce the irradiation to healthy tissue in a patient. The system has the following features: A motion tracking and processing unit recognizes a gold marker inserted in or near a tumor in real time by the pattern matching of a predetermined template image and acquired X-ray fluoroscopic images. When the gold marker is within a planned area, that is to say, when a tumor enters a target irradiation area, a gate signal is sent to a linear accelerator. A railway unit is equipped with two X-ray tubes and two detectors, which are controlled separately with their own drive mechanism. They travel with high accuracy and reproducibility to the best position for monitoring the gold marker. A synchronization controller controls the timing for X-ray fluoroscopy and the gate signals to the linear accelerator. The controller works for two types of detectors: a color X-ray detector and a flat panel detector (FPD). (author)

Angelina′s choice

Directory of Open Access Journals (Sweden)

Nishu Singh Goel

2013-01-01

Full Text Available This is an opinion piece on how a celebrity′s personal choice to undergo prophylactic mastectomy on discovery of an aberrant gene, when publicly promoted, carries in itself the power to influence and impact healthcare trends and decisions. When celebrities advocate causes that are universally and uniformly acceptable and indisputable as the best in the realm of healthcare and cure (e.g. no smoking, it creates well-being and awareness in society at large. But those which are personal choices made out of a repertoire of other available and effective options may, because of celebrity preference, don the mantle of a norm. They thus run the danger of being blindly replicated by others without proper awareness and knowledge of the true potential of disease, risk factors, and other existing remedial or risk-reducing measures. Society should thus be encouraged to question, debate, and understand the validity, authenticity, and reason of the choices, especially those with a medical basis. This tempering of information with intelligence and rationale and making informed choices based on facts will serve humanity as a whole.

A phase I dose escalation study of hypofractionated stereotactic radiotherapy as salvage therapy for persistent or recurrent malignant glioma

International Nuclear Information System (INIS)

Hudes, Richard S.; Corn, Benjamin W.; Werner-Wasik, Maria; Andrews, David; Rosenstock, Jeffrey; Thoron, Louisa; Downes, Beverly; Curran, Walter J.

1999-01-01

Purpose: A phase I dose escalation of hypofractionated stereotactic radiotherapy (H-SRT) in recurrent or persistent malignant gliomas as a means of increasing the biologically effective dose and decreasing the high rate of reoperation due to toxicity associated with single-fraction stereotactic radiosurgery (SRS) and brachytherapy. Materials and Methods: From November 1994 to September 1996, 25 lesions in 20 patients with clinical and/or imaging evidence of malignant glioma persistence or recurrence received salvage H-SRT. Nineteen patients at the time of initial diagnosis had glioblastoma multiforme (GBM) and one patient had an anaplastic astrocytoma. All of these patients with tumor persistence or recurrence had received initial fractionated radiation therapy (RT) with a mean and median dose of 60 Gy (44.0-72.0 Gy). The median time from completion of initial RT to H-SRT was 3.1 months (0.7-45.5 months). Salvage H-SRT was delivered using daily 3.0-3.5 Gy fractions (fxs). Three different total dose levels were sequentially evaluated: 24.0 Gy/3.0 Gy fxs (five lesions), 30.0 Gy/3.0 Gy fxs (10 lesions), and 35.0 Gy/3.5 Gy fxs (nine lesions). Median treated tumor volume measured 12.66 cc (0.89-47.5 cc). The median ratio of prescription volume to tumor volume was 2.8 (1.4-5.0). Toxicity was judged by RTOG criteria. Response was determined by clinical neurologic improvement, a decrease in steroid dose without clinical deterioration, and/or radiologic imaging. Results: No grade 3 toxicities were observed and no reoperation due to toxicity was required. At the time of analysis, 13 of 20 patients had died. The median survival time from the completion of H-SRT is 10.5 months with a 1-year survival rate of 20%. Neurological improvement was found in 45% of patients. Decreased steroid requirements occurred in 60% of patients. Minor imaging response was noted in 22% of patients. Using Fisher's exact test, response of any kind correlated strongly to total dose (p = 0.0056). None

An in vitro method for comparing biocompatibility of materials for extracorporeal circulation.

Science.gov (United States)

Peek, Giles J; Scott, Richard; Killer, Hilliary M; Firmin, Richard K

2002-03-01

We measured the response of fresh heparinized human blood to recirculation through circuits made of LVA (Portex Industries, Hythe, Kent, UK), SRT (Rehau UK, Langley, Slough, UK) and Tygon S-65-HL (Norton Performance Plastics, Corby, Northants, UK), as control. Circuit construction: 1/2 in. tubing, heat exchanger (Dideco D-720P), Stockert roller pump, just underoccluded, Cincinnati Sub Zero heater, circuit volume of 500 ml. Flow 3.45 l/min, 37 degrees C. at 10 min, 1, 2, 4 and 6 h. n=5 in each group; 2/5 SRT experiments were stopped at 45 and 60 min due to overpressurization. Baseline activated clotting time (ACT) of 300 s, increasing in all groups as fibrinogen fell to zero with SRT and LVA. Minimum fibrinogen was 1 g/l for Tygon. Absolute thrombocytopenia occurred (SRT and LVA 60 min and Tygon 240 min). International normalized ratio (INR) in both the SRT and LVA circuits increased, but mean increase for Tygon (0.56) was smaller than the other two materials. Plasma free haemoglobin increased in all three materials; the increase was greater in the LVA circuits compared to the control. C5b9 levels increased equally in all groups. Lactoferrin levels rose equally in all groups to a maximum at 150 min. The neutrophil counts fell, mirroring the lactoferrin. The total white cell counts also fell in all groups; in the LVA circuits, the fall was significantly lower than in the control. Rapid disappearance of platelets and fibrinogen from the blood in the SRT and LVA circuits excludes them both from extracorporeal use. Paradoxically, SRT caused the least complement activation of the three materials. This method can be used to compare biocompatibility.

Exploring alternatives to rational choice in models of Behaviour:An investigation using travel mode choice

OpenAIRE

Thomas, Gregory Owen

2014-01-01

The car is the most popular travel mode in the UK, but reliance on the car has numerous negative effects on health, the economy, and the environment. Encouraging sustainable travel mode choices (modal choice) can minimise these problems. To promote behaviour change, psychologists have an interest in understanding modal choice. Historically, modal choice has been understood as a reasoned and rational decision that requires a conscious assessment of thoughts and attitudes: but evidence suggests...

Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): The role of executive and non-executive functions.

Science.gov (United States)

Hudec, Kristen L; Alderson, R Matt; Patros, Connor H G; Lea, Sarah E; Tarle, Stephanie J; Kasper, Lisa J

2015-01-01

Motor activity of boys (age 8-12 years) with (n=19) and without (n=18) ADHD was objectively measured with actigraphy across experimental conditions that varied with regard to demands on executive functions. Activity exhibited during two n-back (1-back, 2-back) working memory tasks was compared to activity during a choice-reaction time (CRT) task that placed relatively fewer demands on executive processes and during a simple reaction time (SRT) task that required mostly automatic processing with minimal executive demands. Results indicated that children in the ADHD group exhibited greater activity compared to children in the non-ADHD group. Further, both groups exhibited the greatest activity during conditions with high working memory demands, followed by the reaction time and control task conditions, respectively. The findings indicate that large-magnitude increases in motor activity are predominantly associated with increased demands on working memory, though demands on non-executive processes are sufficient to elicit small to moderate increases in motor activity as well. Published by Elsevier Ltd.

Evoked Emotions Predict Food Choice

NARCIS (Netherlands)

Dalenberg, Jelle R.; Gutjar, Swetlana; ter Horst, Gert J.; de Graaf, Kees; Renken, Remco J.; Jager, Gerry

2014-01-01

In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments.

Woman, M.D.: issues, perceptions and choices.

Science.gov (United States)

Johns, C J

1996-01-01

I would end with some summarizing points and questions. 1. A majority of women identify gender-related issues influencing their career choices and pathways. 2. Women are diverse in their choices and priorities, with varying balances of personal and professional life. 3. Eighty-three percent of the women responding to the survey have married, and 82% of those married have children. They thus are likely to have two sets of seriously competing responsibilities. 4. It is possible to identify especially promising women during residency or fellowship. Exploring their priorities and values with good mentors will be important to avoid short-changing academic medicine of competent women. 5. Men and women need to be SUPERCHOOSERS in making the choices right for that individual, rather than superwomen or supermen. 6. We can question whether the development and potential of women (and some men) in academic medicine could be enhanced by: a. Consideration of guidance or support for child care resources? b. Flexibility in the system (tenure clock, etc.)? c. Identification of limited full-time clinical or research opportunities for faculty with young children or unusual family demands? d. Facilitation of bridging after a period of part-time activity or re-entry after limited participation? e. Consideration of part-time work at home and flexible on-site work hours for periods of special family demands? Finally, a supportive work environment is important for both men and women in medicine and is an essential priority in academic medicine. Medicine is a wonderful field. Academic medicine on my terms, to include family, has been very rewarding. Sometimes there also have been disappointments, in that I have fallen short of some of my aspirations. However, I must accept the responsibility for my choices. I owe a great debt to many of the men and women of the American Clinical and Climatological Association and of Johns Hopkins who are both friends and colleagues and especially to my

The effect of choice on the physiology of emotion: an affective startle modulation study.

Science.gov (United States)

Genevsky, Alexander; Gard, David E

2012-04-01

The affective startle modulation task has been an important measure in understanding physiological aspects of emotion and motivational responses. Research utilizing this method has relied primarily on a 'passive' viewing paradigm, which stands in contrast to everyday life where much of emotion and motivation involves some active choice or agency. The present study investigated the role of choice on the physiology of emotion. Eighty-four participants were randomized into 'choice' (n=44) or 'no-choice' (n=40) groups distinguished by the ability to choose between stimuli. EMG eye blink responses were recorded in both anticipation and stimulus viewing. Results indicated a significant attenuation of the startle magnitude in choice condition trials (relative to no-choice) across all picture categories and probe times. We interpret these findings as an indication that the act of choice may decrease one's defensive response, or conversely, lacking choice may heighten the defensive response. Implications for future research are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Using automatic item generation to create multiple-choice test items.

Science.gov (United States)

Gierl, Mark J; Lai, Hollis; Turner, Simon R

2012-08-01

Many tests of medical knowledge, from the undergraduate level to the level of certification and licensure, contain multiple-choice items. Although these are efficient in measuring examinees' knowledge and skills across diverse content areas, multiple-choice items are time-consuming and expensive to create. Changes in student assessment brought about by new forms of computer-based testing have created the demand for large numbers of multiple-choice items. Our current approaches to item development cannot meet this demand. We present a methodology for developing multiple-choice items based on automatic item generation (AIG) concepts and procedures. We describe a three-stage approach to AIG and we illustrate this approach by generating multiple-choice items for a medical licensure test in the content area of surgery. To generate multiple-choice items, our method requires a three-stage process. Firstly, a cognitive model is created by content specialists. Secondly, item models are developed using the content from the cognitive model. Thirdly, items are generated from the item models using computer software. Using this methodology, we generated 1248 multiple-choice items from one item model. Automatic item generation is a process that involves using models to generate items using computer technology. With our method, content specialists identify and structure the content for the test items, and computer technology systematically combines the content to generate new test items. By combining these outcomes, items can be generated automatically. © Blackwell Publishing Ltd 2012.

Manipulating a stated choice experiment

DEFF Research Database (Denmark)

Fosgerau, Mogens; Borjesson, Maria

2015-01-01

This paper considers the design of a stated choice experiment intended to measure the marginal rate of substitution (MRS) between cost and an attribute such as time using a conventional logit model. Focusing the experimental design on some target MRS will bias estimates towards that value....... The paper shows why this happens. The resulting estimated MRS can then be manipulated by adapting the target MRS in the experimental design. (C) 2015 Elsevier Ltd. All rights reserved....

The impact of presentation format on visual attention and choice in discrete choice experiments

DEFF Research Database (Denmark)

Mueller Loose, Simone; Orquin, Jacob Lund

with visual attributes, or as product mock-ups simulating realistic products as close as possible. So far little is known about how presentation formats affect visual attention patterns and choice behavior. This study addresses the question by analysing visual attention and part-worth utilities in choice...... experiments across three different presentation formats. Method. Participants’ visual attention was measured by means of eye tracking during a discrete choice experiment for yoghurt products varying on six attributes with two to four levels. The study used a mixed within-between subjects design in which...... the presentation format varied between a verbal information table, a table with visual attributes levels and a realistic product mock-up presentation. Results. A strong relationship between attention and choice was observed so that attributes with a higher importance for participant choices also received a higher...

The Role of Time Perspective, Motivation, Attitude, and Preparation in Educational Choice and Study Progress

NARCIS (Netherlands)

Slijper, Jeany; Kunnen, Elske; Onstenk, Jeroen; van Geert, Paul

2016-01-01

The present study examined the relation between study progress in the first year of education and different aspects of the process of study choice of 89 students of higher professional education. This study consists of three parts. Firstly, we explored which concepts are important in open interviews

The axiom of choice

CERN Document Server

Jech, Thomas J

2008-01-01

Comprehensive in its selection of topics and results, this self-contained text examines the relative strengths and consequences of the axiom of choice. Each chapter contains several problems, graded according to difficulty, and concludes with some historical remarks.An introduction to the use of the axiom of choice is followed by explorations of consistency, permutation models, and independence. Subsequent chapters examine embedding theorems, models with finite supports, weaker versions of the axiom, and nontransferable statements. The final sections consider mathematics without choice, cardin

Discrete Choice and Rational Inattention

DEFF Research Database (Denmark)

Fosgerau, Mogens; Melo, Emerson; de Palma, André

2017-01-01

This paper establishes a general equivalence between discrete choice and rational inattention models. Matejka and McKay (2015, AER) showed that when information costs are modelled using the Shannon entropy, the result- ing choice probabilities in the rational inattention model take the multinomial...... logit form. We show that when information costs are modelled using a class of generalized entropies, then the choice probabilities in any rational inattention model are observationally equivalent to some additive random utility discrete choice model and vice versa. This equivalence arises from convex...

A singular choice for multiple choice

DEFF Research Database (Denmark)

Frandsen, Gudmund Skovbjerg; Schwartzbach, Michael Ignatieff

2006-01-01

How should multiple choice tests be scored and graded, in particular when students are allowed to check several boxes to convey partial knowledge? Many strategies may seem reasonable, but we demonstrate that five self-evident axioms are sufficient to determine completely the correct strategy. We ...

The Making of Informed Choice in Midwifery: A Feminist Experiment in Care.

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MacDonald, Margaret E

2017-11-15

This paper is about the clinical principle of informed choice-the hallmark feature of the midwifery model of care in Ontario, Canada. Drawing on ethnographic history interviews with midwives, I trace the origins of the idea of informed choice to its roots in the social movement of midwifery in North America in the late 1960s and 1970s. At that time informed choice was not the distinctive feature of midwifery but was deeply embedded what I call midwifery's feminist experiment in care. But as midwifery in Ontario transitioned from a social movement to a full profession within the formal health care system, informed choice was strategically foregrounded in order to make the midwifery model of care legible and acceptable to a skeptical medical profession, conservative law makers, and a mainstream clientele. As mainstream biomedicine now takes up the rhetoric of patient empowerment and informed choice, this paper is at once a nuanced history of the making of the concept and also a critique of the ascendant 'regime of choice' in contemporary health care, inspired by the reflections of the midwives in my study for whom choice is impossible without care.

The role of sedation tests in identifying sedative drug effects in healthy volunteers and their power to dissociate sedative-related impairments from memory dysfunctions.

Science.gov (United States)

Wezenberg, E; Sabbe, B G C; Hulstijn, W; Ruigt, G S F; Verkes, R J

2007-08-01

The study investigated whether four specified drugs would show similar patterns on tests considered to measure sedation. In addition, their drug-effect patterns on sedation and memory performance were compared to determine whether the sedative effects could be differentiated from the memory effects. Two double-blind, placebo-controlled, crossover studies, each with 16 healthy volunteers, were performed, one testing lorazepam (2.5 mg) and mirtazapine (15 mg) and the other olanzapine (10 mg) and haloperidol (2.5 mg). Subjective sedation was assessed by means of visual analogue scales (VAS) and objective sedation using a simple-reaction-time (SRT) task and a choice-reaction-time (CRT) task, code substitution (symbol digit substitution test (SDST)) and the peak velocity of saccadic eye movements (SEM). A verbal memory test (VMT) was administered to evaluate memory capacity. Apart from haloperidol, all drugs proved to impair performance on all five sedation indices. Contrary to the VAS, the objective measures yielded different response profiles. Two types of drug-effect patterns emerged: one for greater impairments in response speed (SRT, SEM) and one for greater impairments in information processing (CRT, SDST). Lorazepam and olanzapine impeded memory performance, whereas mirtazapine did not. With the use of standardized scores it proved possible to differentiate between the size of the effects of the drugs on the sedation and memory tests. To accurately assess the level and nature of sedation and to differentiate sedation from memory impairments different types of sedation measures are required. Besides studying the subjective effects, it is recommended to also test psychomotor responses and information processing speed.

Choice experiments versus revealed choice models : a before-after study of consumer spatial shopping behavior

NARCIS (Netherlands)

Timmermans, H.J.P.; Borgers, A.W.J.; Waerden, van der P.J.H.J.

1992-01-01

The purpose of this article is to compare a set of multinomial logit models derived from revealed choice data and a decompositional choice model derived from experimental data in terms of predictive success in the context of consumer spatial shopping behavior. Data on consumer shopping choice

Preference as a Function of Active Interresponse Times: A Test of the Active Time Model

Science.gov (United States)

Misak, Paul; Cleaveland, J. Mark

2011-01-01

In this article, we describe a test of the active time model for concurrent variable interval (VI) choice. The active time model (ATM) suggests that the time since the most recent response is one of the variables controlling choice in concurrent VI VI schedules of reinforcement. In our experiment, pigeons were trained in a multiple concurrent…

Computational mate choice: theory and empirical evidence.

Science.gov (United States)

Castellano, Sergio; Cadeddu, Giorgia; Cermelli, Paolo

2012-06-01

The present review is based on the thesis that mate choice results from information-processing mechanisms governed by computational rules and that, to understand how females choose their mates, we should identify which are the sources of information and how they are used to make decisions. We describe mate choice as a three-step computational process and for each step we present theories and review empirical evidence. The first step is a perceptual process. It describes the acquisition of evidence, that is, how females use multiple cues and signals to assign an attractiveness value to prospective mates (the preference function hypothesis). The second step is a decisional process. It describes the construction of the decision variable (DV), which integrates evidence (private information by direct assessment), priors (public information), and value (perceived utility) of prospective mates into a quantity that is used by a decision rule (DR) to produce a choice. We make the assumption that females are optimal Bayesian decision makers and we derive a formal model of DV that can explain the effects of preference functions, mate copying, social context, and females' state and condition on the patterns of mate choice. The third step of mating decision is a deliberative process that depends on the DRs. We identify two main categories of DRs (absolute and comparative rules), and review the normative models of mate sampling tactics associated to them. We highlight the limits of the normative approach and present a class of computational models (sequential-sampling models) that are based on the assumption that DVs accumulate noisy evidence over time until a decision threshold is reached. These models force us to rethink the dichotomy between comparative and absolute decision rules, between discrimination and recognition, and even between rational and irrational choice. Since they have a robust biological basis, we think they may represent a useful theoretical tool for

Bioflocculation of grey water for improved energy recovery within decentralized sanitation concepts.

Science.gov (United States)

Hernández Leal, L; Temmink, H; Zeeman, G; Buisman, C J N

2010-12-01

Bioflocculation of grey water was tested with a lab-scale membrane bioreactor in order to concentrate the COD. Three concentration factors were tested based on the ratio of sludge retention time (SRT) and hydraulic retention time (HRT): 3, 8 and 12. COD concentration factor was up to 7.1, achieving a final concentration of 7.2 g COD L(-1). Large fractions of suspended COD were recovered in the concentrate (57%, 81% and 82% at SRT/HRT ratios of 3, 8 and 12, respectively) indicating a strong bioflocculation of grey water. A maximum of 11% of COD mineralization of grey water was measured at the longest SRT tested (1 d). The integration of bioflocculation of grey water in decentralized sanitation concepts may increase the overall production of methane by 73%, based on the biogas produced by black water only. Therefore, bioflocculation is a promising grey water pre-treatment step for energy recovery within decentralized sanitation concepts. 2010 Elsevier Ltd. All rights reserved.

Chance, choice, and the future of reproduction.

Science.gov (United States)

Miller, W B

1983-11-01

The evolution of reproduction has been characterized by the development of complex biological and behavioral mechanisms that serve to regulate chance events. Human reproduction has been characterized by the increasing importance of individual choice. Some contemporary manifestations of this broad trend are the high incidence of contraceptive and "proceptive" behavior among couples in Western, industrialized nations. The former behavior willingly attempts to prevent conception while the latter actively attempts to induce conception (such as concentrating intercourse around the time of ovulation). Both patterns of behavior indicate that a choice is being made. A 3-year study of 1000 women revealed proceptive behavior as the most important factor predicting occurance of conception among married couples in the United States. The general strategeis people follow while making childbearing decisions: termination, sequencing, and pre-planning form a continuum following the historical trend toward greater reproductive control. In the terminating strategy, a couple makes no decision about child bearing until the number of children they have become enough or too much. In the sequencing strategy, decisions to have children are made 1 child at a time until a satisfactory limit is reached. In the pre-planning strategy, a plan is worked out ahead of time and is subsequently carried out. As new reproductive technology is introduced and as progressive change is made in society's reproductive related values and beliefs, choice will continue to dominate chance as the highly likely trend for the future of reproduction. Surrogate maternity is just 1 example of this trend. However, these new options, which culminate in the theory and practice of "progensis," (still in its infancy), as well as offering a rich opportunity, can also incur psychological burdens on a couple. Thus, as with any kind of freedom, these developments will require care, caution and responsibility.

Sortase-Mediated Ligation of Purely Artificial Building Blocks

Directory of Open Access Journals (Sweden)

Xiaolin Dai

2018-02-01

Full Text Available Sortase A (SrtA from Staphylococcus aureus has been often used for ligating a protein with other natural or synthetic compounds in recent years. Here we show that SrtA-mediated ligation (SML is universally applicable for the linkage of two purely artificial building blocks. Silica nanoparticles (NPs, poly(ethylene glycol and poly(N-isopropyl acrylamide are chosen as synthetic building blocks. As a proof of concept, NP–polymer, NP–NP, and polymer–polymer structures are formed by SrtA catalysis. Therefore, the building blocks are equipped with the recognition sequence needed for SrtA reaction—the conserved peptide LPETG—and a pentaglycine motif. The successful formation of the reaction products is shown by means of transmission electron microscopy (TEM, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS, and dynamic light scattering (DLS. The sortase catalyzed linkage of artificial building blocks sets the stage for the development of a new approach to link synthetic structures in cases where their synthesis by established chemical methods is complicated.

Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

Science.gov (United States)

Ge, Huoqing; Batstone, Damien; Keller, Jurg

2016-01-01

The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

On school choice and test-based accountability.

Directory of Open Access Journals (Sweden)

Damian W. Betebenner

2005-10-01

Full Text Available Among the two most prominent school reform measures currently being implemented in The United States are school choice and test-based accountability. Until recently, the two policy initiatives remained relatively distinct from one another. With the passage of the No Child Left Behind Act of 2001 (NCLB, a mutualism between choice and accountability emerged whereby school choice complements test-based accountability. In the first portion of this study we present a conceptual overview of school choice and test-based accountability and explicate connections between the two that are explicit in reform implementations like NCLB or implicit within the market-based reform literature in which school choice and test-based accountability reside. In the second portion we scrutinize the connections, in particular, between school choice and test-based accountability using a large western school district with a popular choice system in place. Data from three sources are combined to explore the ways in which school choice and test-based accountability draw on each other: state assessment data of children in the district, school choice data for every participating student in the district choice program, and a parental survey of both participants and non-participants of choice asking their attitudes concerning the use of school report cards in the district. Results suggest that choice is of benefit academically to only the lowest achieving students, choice participation is not uniform across different ethnic groups in the district, and parents' primary motivations as reported on a survey for participation in choice are not due to test scores, though this is not consistent with choice preferences among parents in the district. As such, our results generally confirm the hypotheses of choice critics more so than advocates. Keywords: school choice; accountability; student testing.

What counts as a choice? U.S. Americans are more likely than Indians to construe actions as choices.

Science.gov (United States)

Savani, Krishna; Markus, Hazel Rose; Naidu, N V R; Kumar, Satishchandra; Berlia, Neha

2010-03-01

People everywhere select among multiple alternatives, but are they always making choices? In five studies, we found that people in U.S. American contexts, where the disjoint model of agency is prevalent, are more likely than those in Indian contexts to construe their own and other individuals' behaviors as choices, to construe ongoing behaviors and behaviors recalled from memory as choices, to construe naturally occurring and experimentally controlled behaviors as choices, to construe mundane and important actions as choices, and to construe personal and interpersonal actions as choices. Indians showed a greater tendency to construe actions as choices when these actions involved responding to other people than when they did not. These findings show that whether people construe actions as choices is significantly shaped by sociocultural systems of meanings and practices. Together, they suggest that the positive consequences associated with maximizing the availability of personal choice may not be universal and instead may be limited to North American contexts.

Making Smart Food Choices

Science.gov (United States)

... turn JavaScript on. Feature: Healthy Aging Making Smart Food Choices Past Issues / Winter 2015 Table of Contents Everyday ... NIH www.nia.nih.gov/Go4Life Making Smart Food Choices To maintain a healthy weight, balance the calories ...

The drift diffusion model as the choice rule in reinforcement learning.

Science.gov (United States)

Pedersen, Mads Lund; Frank, Michael J; Biele, Guido

2017-08-01

Current reinforcement-learning models often assume simplified decision processes that do not fully reflect the dynamic complexities of choice processes. Conversely, sequential-sampling models of decision making account for both choice accuracy and response time, but assume that decisions are based on static decision values. To combine these two computational models of decision making and learning, we implemented reinforcement-learning models in which the drift diffusion model describes the choice process, thereby capturing both within- and across-trial dynamics. To exemplify the utility of this approach, we quantitatively fit data from a common reinforcement-learning paradigm using hierarchical Bayesian parameter estimation, and compared model variants to determine whether they could capture the effects of stimulant medication in adult patients with attention-deficit hyperactivity disorder (ADHD). The model with the best relative fit provided a good description of the learning process, choices, and response times. A parameter recovery experiment showed that the hierarchical Bayesian modeling approach enabled accurate estimation of the model parameters. The model approach described here, using simultaneous estimation of reinforcement-learning and drift diffusion model parameters, shows promise for revealing new insights into the cognitive and neural mechanisms of learning and decision making, as well as the alteration of such processes in clinical groups.

A practical test for the choice of mixing distribution in discrete choice models

DEFF Research Database (Denmark)

Fosgerau, Mogens; Bierlaire, Michel

2007-01-01

The choice of a specific distribution for random parameters of discrete choice models is a critical issue in transportation analysis. Indeed, various pieces of research have demonstrated that an inappropriate choice of the distribution may lead to serious bias in model forecast and in the estimated...... means of random parameters. In this paper, we propose a practical test, based on seminonparametric techniques. The test is analyzed both on synthetic and real data, and is shown to be simple and powerful. (c) 2007 Elsevier Ltd. All rights reserved....

Does the number of choice sets matter? Results from a web survey applying a discrete choice experiment

DEFF Research Database (Denmark)

Bech, Mickael; Kjær, Trine; Lauridsen, Jørgen Trankjær

2011-01-01

choice sets presented to each respondent on response rate, self-reported choice certainty, perceived choice difficulty, willingness-to-pay (WTP) estimates, and response variance. A sample of 1053 respondents was exposed to 5, 9 or 17 choice sets in a DCE eliciting preferences for dental services. Our...... results showed no differences in response rates and no systematic differences in the respondents' self-reported perception of the uncertainty of their DCE answers. There were some differences in WTP estimates suggesting that estimated preferences are to some extent context-dependent, but no differences...... in standard deviations for WTP estimates or goodness-of-fit statistics. Respondents exposed to 17 choice sets had somewhat higher response variance compared to those exposed to 5 choice sets, indicating that cognitive burden may increase with the number of choice sets beyond a certain threshold. Overall, our...

Food choices, physical activity levels and other factors associated

African Journals Online (AJOL)

user

choice was made between one and two times a day. The frequency of .... with the development/prevention/management of obesity, diabetes ..... undertakes is whether sport is offered at the ..... Uhlaba Usamila – The South African Youth Risk.

How the Measurement of Store Choice Behaviour Moderates the Relationship between Distance and Store Choice Behaviour

DEFF Research Database (Denmark)

Hansen, Torben; Cumberland, Flemming; Solgaard, Hans Stubbe

2013-01-01

The influence of distance on consumer store choice behaviour has been considered in many studies. In that respect, frequency and budget share are frequently used methods of measurement to determine the consumer's store choice behavour. In this study, we propose that the significance of distance...... is influenced by the way in which store choice behaviour is conceptualized. A survey among 631 consuemrs was performed in order to examine the research proposition. Structural equation results suggest that the negative effect of distance on store choice behaviour is larger when store choice behaviour...... is measured as number of visits to a particular store than wehen store cjoice behaviour is measured as the percentage of budget spend at a particular store. Our results indicate that researchers should carefully consider the measurement of store choice behaviour when carrying out empirical research invlving...

School Choice and the Branding of Catholic Schools

Science.gov (United States)

Trivitt, Julie R.; Wolf, Patrick J.

2011-01-01

How useful are "corporate brands" in markets? In theory, brands convey reliable information, providing consumers with shortcuts to time-consuming provider searches. We examine the usefulness of a corporate brand when parental school choice is expanded through K-12 tuition scholarships. Specifically, we evaluate whether Catholic schools…

Modeling Dynamic Food Choice Processes to Understand Dietary Intervention Effects.

Science.gov (United States)

Marcum, Christopher Steven; Goldring, Megan R; McBride, Colleen M; Persky, Susan

2018-02-17

Meal construction is largely governed by nonconscious and habit-based processes that can be represented as a collection of in dividual, micro-level food choices that eventually give rise to a final plate. Despite this, dietary behavior intervention research rarely captures these micro-level food choice processes, instead measuring outcomes at aggregated levels. This is due in part to a dearth of analytic techniques to model these dynamic time-series events. The current article addresses this limitation by applying a generalization of the relational event framework to model micro-level food choice behavior following an educational intervention. Relational event modeling was used to model the food choices that 221 mothers made for their child following receipt of an information-based intervention. Participants were randomized to receive either (a) control information; (b) childhood obesity risk information; (c) childhood obesity risk information plus a personalized family history-based risk estimate for their child. Participants then made food choices for their child in a virtual reality-based food buffet simulation. Micro-level aspects of the built environment, such as the ordering of each food in the buffet, were influential. Other dynamic processes such as choice inertia also influenced food selection. Among participants receiving the strongest intervention condition, choice inertia decreased and the overall rate of food selection increased. Modeling food selection processes can elucidate the points at which interventions exert their influence. Researchers can leverage these findings to gain insight into nonconscious and uncontrollable aspects of food selection that influence dietary outcomes, which can ultimately improve the design of dietary interventions.

One-reason decision making in risky choice? A closer look at the priority heuristic

Directory of Open Access Journals (Sweden)

Benjamin E. Hilbig

2008-08-01

Full Text Available Although many models for risky choices between gambles assume that information is somehow integrated, the recently proposed priority heuristic (PH claims that choices are based on one piece of information only. That is, although the current reason for a choice according to the PH can vary, all other reasons are claimed to be ignored. However, the choices predicted by the PH and other pieces of information are often confounded, thus rendering critical tests of whether decisions are actually based on one reason only, impossible. The current study aims to remedy this problem by manipulating the number of reasons additionally in line with the choice implied by the PH. The results show that participants' choices and decision times depend heavily on the number of reasons in line with the PH --- thus contradicting the notion of non-compensatory, one-reason decision making.

Intelligence, Inspection Time, and Decision Time.

Science.gov (United States)

Bates, Timothy C.; Eysenck, Hans J.

1993-01-01

Relationships among Multidimensional Aptitude Battery scores, inspection time, choice reaction time, and the odd-man procedure were investigated for 63 female and 25 male adults. No significant relationships were found for these mental speed measures and the Eysenck Personality Questionnaire-Revised dimensions of extraversion, neuroticism, and…

School Choice: The Personal and the Political

Science.gov (United States)

Shuls, James V.

2018-01-01

Enrollment in school choice programs is growing, so is overall support for school choice. Many have analyzed what demographic characteristics impact attitudes towards school choice. This article adds to the literature by exploring the interaction between personal decisions regarding school choice and broader support for school choice programs.…

Reducing the number of options on multiple-choice questions: response time, psychometrics and standard setting.

Science.gov (United States)

Schneid, Stephen D; Armour, Chris; Park, Yoon Soo; Yudkowsky, Rachel; Bordage, Georges

2014-10-01

Despite significant evidence supporting the use of three-option multiple-choice questions (MCQs), these are rarely used in written examinations for health professions students. The purpose of this study was to examine the effects of reducing four- and five-option MCQs to three-option MCQs on response times, psychometric characteristics, and absolute standard setting judgements in a pharmacology examination administered to health professions students. We administered two versions of a computerised examination containing 98 MCQs to 38 Year 2 medical students and 39 Year 3 pharmacy students. Four- and five-option MCQs were converted into three-option MCQs to create two versions of the examination. Differences in response time, item difficulty and discrimination, and reliability were evaluated. Medical and pharmacy faculty judges provided three-level Angoff (TLA) ratings for all MCQs for both versions of the examination to allow the assessment of differences in cut scores. Students answered three-option MCQs an average of 5 seconds faster than they answered four- and five-option MCQs (36 seconds versus 41 seconds; p = 0.008). There were no significant differences in item difficulty and discrimination, or test reliability. Overall, the cut scores generated for three-option MCQs using the TLA ratings were 8 percentage points higher (p = 0.04). The use of three-option MCQs in a health professions examination resulted in a time saving equivalent to the completion of 16% more MCQs per 1-hour testing period, which may increase content validity and test score reliability, and minimise construct under-representation. The higher cut scores may result in higher failure rates if an absolute standard setting method, such as the TLA method, is used. The results from this study provide a cautious indication to health professions educators that using three-option MCQs does not threaten validity and may strengthen it by allowing additional MCQs to be tested in a fixed amount

Multiple-relaxation-time lattice Boltzmann model for compressible fluids

International Nuclear Information System (INIS)

Chen Feng; Xu Aiguo; Zhang Guangcai; Li Yingjun

2011-01-01

We present an energy-conserving multiple-relaxation-time finite difference lattice Boltzmann model for compressible flows. The collision step is first calculated in the moment space and then mapped back to the velocity space. The moment space and corresponding transformation matrix are constructed according to the group representation theory. Equilibria of the nonconserved moments are chosen according to the need of recovering compressible Navier-Stokes equations through the Chapman-Enskog expansion. Numerical experiments showed that compressible flows with strong shocks can be well simulated by the present model. The new model works for both low and high speeds compressible flows. It contains more physical information and has better numerical stability and accuracy than its single-relaxation-time version. - Highlights: → We present an energy-conserving MRT finite-difference LB model. → The moment space is constructed according to the group representation theory. → The new model works for both low and high speeds compressible flows. → It has better numerical stability and wider applicable range than its SRT version.

Long-Term Outcomes After High-Dose Postprostatectomy Salvage Radiation Treatment

International Nuclear Information System (INIS)

Goenka, Anuj; Magsanoc, Juan Martin; Pei Xin; Schechter, Michael; Kollmeier, Marisa; Cox, Brett; Scardino, Peter T.; Eastham, James A.; Zelefsky, Michael J.

2012-01-01

Purpose: To review the impact of high–dose radiotherapy (RT) in the postprostatectomy salvage setting on long-term biochemical control and distant metastases–free survival, and to identify clinical and pathologic predictors of outcomes. Methods and Materials: During 1988–2007, 285 consecutive patients were treated with salvage RT (SRT) after radical prostatectomy. All patients were treated with either three-dimensional conformal RT or intensity-modulated RT. Two hundred seventy patients (95%) were treated to a dose ≥66 Gy, of whom 205 (72%) received doses ≥70 Gy. Eighty-seven patients (31%) received androgen-deprivation therapy as a component of their salvage treatment. All clinical and pathologic records were reviewed to identify treatment risk factors and response. Results: The median follow-up time after SRT was 60 months. Seven-year actuarial prostate-specific antigen (PSA) relapse-free survival and distant metastases–free survival were 37% and 77%, respectively. Independent predictors of biochemical recurrence were vascular invasion (p 0.4 ng/mL (p < 0.01), androgen-deprivation therapy (p = 0.03), Gleason score ≥7 (p = 0.02), and seminal vesicle involvement (p = 0.05). Salvage RT dose ≥70 Gy was not associated with improvement in biochemical control. A doubling time <3 months was the only independent predictor of metastatic disease (p < 0.01). There was a trend suggesting benefit of SRT dose ≥70 Gy in preventing clinical local failure in patients with radiographically visible local disease at time of SRT (7 years: 90% vs. 79.1%, p = 0.07). Conclusion: Salvage RT provides effective long-term biochemical control and freedom from metastasis in selected patients presenting with detectable PSA after prostatectomy. Androgen-deprivation therapy was associated with improvement in biochemical progression-free survival. Clinical local failures were rare but occurred most commonly in patients with greater burden of disease at time of SRT as reflected by

Long-Term Outcomes After High-Dose Postprostatectomy Salvage Radiation Treatment

Energy Technology Data Exchange (ETDEWEB)

Goenka, Anuj; Magsanoc, Juan Martin; Pei Xin; Schechter, Michael; Kollmeier, Marisa; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Scardino, Peter T.; Eastham, James A. [Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

2012-09-01

Purpose: To review the impact of high-dose radiotherapy (RT) in the postprostatectomy salvage setting on long-term biochemical control and distant metastases-free survival, and to identify clinical and pathologic predictors of outcomes. Methods and Materials: During 1988-2007, 285 consecutive patients were treated with salvage RT (SRT) after radical prostatectomy. All patients were treated with either three-dimensional conformal RT or intensity-modulated RT. Two hundred seventy patients (95%) were treated to a dose {>=}66 Gy, of whom 205 (72%) received doses {>=}70 Gy. Eighty-seven patients (31%) received androgen-deprivation therapy as a component of their salvage treatment. All clinical and pathologic records were reviewed to identify treatment risk factors and response. Results: The median follow-up time after SRT was 60 months. Seven-year actuarial prostate-specific antigen (PSA) relapse-free survival and distant metastases-free survival were 37% and 77%, respectively. Independent predictors of biochemical recurrence were vascular invasion (p < 0.01), negative surgical margins (p < 0.01), presalvage PSA level >0.4 ng/mL (p < 0.01), androgen-deprivation therapy (p = 0.03), Gleason score {>=}7 (p = 0.02), and seminal vesicle involvement (p = 0.05). Salvage RT dose {>=}70 Gy was not associated with improvement in biochemical control. A doubling time <3 months was the only independent predictor of metastatic disease (p < 0.01). There was a trend suggesting benefit of SRT dose {>=}70 Gy in preventing clinical local failure in patients with radiographically visible local disease at time of SRT (7 years: 90% vs. 79.1%, p = 0.07). Conclusion: Salvage RT provides effective long-term biochemical control and freedom from metastasis in selected patients presenting with detectable PSA after prostatectomy. Androgen-deprivation therapy was associated with improvement in biochemical progression-free survival. Clinical local failures were rare but occurred most commonly in

Your Genes, Your Choices

Science.gov (United States)

Table of Contents Your Genes, Your Choices describes the Human Genome Project, the science behind it, and the ethical, legal, and social issues that are ... Nothing could be further from the truth. Your Genes, Your Choices points out how the progress of ...

Effect of social influence on consumer choice behavior using a sequential stated choice experiment: A study of city trip itinerary choice

NARCIS (Netherlands)

Pan, X.; Rasouli, S.; Timmermans, H.J.P.

2018-01-01

This paper introduces a model that captures the effect of social influence on individual choice behavior. The suggested model shares with previous models the idea to add a term to the deterministic utility function of the choice alternative, chosen by a social network member, to measure an

Effects of fractionated stereotactic radiotherapy for primary hepatocellular carcinoma

International Nuclear Information System (INIS)

Choi, Byeong Ock; Jang, Hong Seok; Kang, Young Nam; Choi, Ihl Bhong; Kang, Ki Mun; Chai, Gyu Young; Lee, Sang Wook

2005-01-01

Reports on the outcome of curative radiotherapy for the primary hepatocellular carcinoma (HCC) are rarely encountered in the literature. In this study, we report our experience of a clinical trial where fractionated stereotactic radiotherapy (SRT) was used in treating a primary HCC. A retrospective analysis was performed on 20 patients who had been histologically diagnosed as HCC and treated by fractionated SRT. The long diameter of tumor measured by CT was 2 ∼ 6.5 cm (average: 3.8 cm). A single dose of radiation used in fractionated SRT was 5 or 10 Gy; each dose was prescribed based on the planning target volume and normalized to 85 ∼ 99% isocenter dose. Patients were treated 3 ∼ 5 times per week for 2 weeks, with each receiving a total dose of 50 Gy (the median dose: 50 Gy). The follow up period was 3 ∼ 55 months (the median follow up period: 23 months). The response rate was 60% (12 patients), with 4 patients showing complete response (20%), 8 patients showing partial response (40%), and 8 patients showing stable disease (40%). The 1-year and 2-year survival rates were 70.0% and 43.1%, respectively,and the median survival time was 20 months. The 1-year and 2-year disease free survival rates were 65% and 32.5%, respectively, and the median disease-free survival rate was 19 months. Some acute complications of the treatment were noted as follows: dyspepsia in 12 patients (60%), nausea/emesis in 8 patients (40%), and transient liver function impairment in 6 patients (30%). However, there was no treatment related death. The study indicates that fractionated SRT is a relatively safe and effective method for treating primary HCC. Thus, fractionated SRT may be suggested as a local treatment for HCC of small lesion and containing a single lesion, when the patients are inoperable or operation is refused by the patients. We thought that fractionated SRT is a challenging treatment modality for the HCC

Multimodal route choice models of public transport passengers in the Greater Copenhagen Area

DEFF Research Database (Denmark)

Anderson, Marie Karen; Nielsen, Otto Anker; Prato, Carlo Giacomo

2014-01-01

Understanding route choice behavior is crucial to explain travelers’ preferences and to predict traffic flows under different scenarios. A growing body of literature has concentrated on public transport users without, however, concentrating on multimodal public transport networks because......,641 public transport users in the Greater Copenhagen Area.A two-stage approach consisting of choice set generation and route choice model estimation allowed uncovering the preferences of the users of this multimodal large-scale public transport network. The results illustrate the rates of substitution...... not only of the in-vehicle times for different public transport modes, but also of the other time components (e.g., access, walking, waiting, transfer) composing the door-to-door experience of using a multimodal public transport network, differentiating by trip length and purpose, and accounting...

Workers' lifestyle choices, working time and job attributes

NARCIS (Netherlands)

Russo, G.; van Hooft, E.; Addabbo, T.; Solinas, G.

2012-01-01

The Netherlands has been dubbed "the only part-time economy". This expression reflects the popularity of part-time jobs in the country, particularly among working women. The beginning of the boom in Dutch part-time work can be traced back to the tripartite agreement of 1982 (the Wassenaar

Performing a Choice-Narrative: A qualitative study of the patterns in STEM students' higher education choices

Science.gov (United States)

Tolstrup Holmegaard, Henriette

2015-06-01

Students' science choices have long attracted attention in both public and research. Recently there has been a call for qualitative studies to explore how choices create a sense of fit for individual students. Therefore, this paper aims to study how science students' choices of higher education are performed and to uncover the patterns of students' construction of their choice-narratives. The paper is based on a qualitative study among 38 Danish upper secondary school students. The theoretical framework is narrative psychology combined with post-structural thinking. The study shows that constructing a choice-narrative is complicated identity-work. First, the students felt encouraged to identify their interests, not only the ones related to the subject matter, but also various interests that were equally negotiated in relation to each other. Second, the choice-narratives were personalised; on the one side articulated as not too predictable, and on the other side appearing realistic and adjusted to the students' sense of self. Third, the choice-narratives were informed, validated and adjusted in the students' social network providing the students with a repertoire of viable pathways. The study demonstrates how cultural discourses about how a proper choice is made set the scene for the students' choices. The study raises some concerns for science education. Improving students' interests in science alone might not lead to increased admission as several interests equally intervene. To attract more students to science, we must consider how to actively engage them in crafting their own education, as a way to support them in making personal sense.

Energy-saving technology choices by Dutch glasshouse firms

NARCIS (Netherlands)

Pietola, K.; Oude Lansink, A.G.J.M.

2006-01-01

This paper estimates a sequence of energy-saving technology choices by Dutch glasshouse firms. The model allows for time-constant, firm-specific effects and serial correlation of errors and it is estimated on panel data over the period 1991¿1995. The unobserved error sequences are simulated in the

Analysing countries' contribution to climate change: scientific and policy-related choices

International Nuclear Information System (INIS)

Elzen, Michel den; Fuglestvedt, Jan; Hoehne, Niklas; Trudinger, Cathy; Lowe, Jason; Matthews, Ben; Romstad, Bard; Pires de Campos, Christiano; Andronova, Natalia

2005-01-01

This paper evaluates the influence of different policy-related and scientific choices on the calculated regional contributions to global climate change (the 'Brazilian Proposal'). Policy-related choices include the time period of emissions, the mix of greenhouse gases and different indicators of climate change impacts. The scientific choices include historical emissions and model representations of the climate system. We generated and compared results of several simple climate models. We find that the relative contributions of different nations to global climate change-from emissions of greenhouse gases alone-are quite robust, despite the varying model complexity and differences in calculated absolute changes. For the default calculations, the average calculated contributions to the global mean surface temperature increase in 2000 are about 40% from OECD, 14% from Eastern Europe and Former Soviet Union, 24% from Asia and 22% from Africa and Latin America. Policy-related choices, such as time period of emissions, climate change indicator and gas mix generally have larger influence on the results than scientific choices. More specifically, choosing a later attribution start date (1990 instead of 1890) for historical emissions, decreases the contributions of regions that started emitting early, such as the OECD countries by 6 percentage points, whereas it increases the contribution of late emitters such as Asia by 8 percentage points. However, only including the fossil CO 2 emissions instead of the emissions of all Kyoto gases (fossil and land use change), increases the OECD contributions by 21 percentage points and decreases the contribution of Asia by 14 percentage points

The Sardinia Radio Telescope . From a technological project to a radio observatory

Science.gov (United States)

Prandoni, I.; Murgia, M.; Tarchi, A.; Burgay, M.; Castangia, P.; Egron, E.; Govoni, F.; Pellizzoni, A.; Ricci, R.; Righini, S.; Bartolini, M.; Casu, S.; Corongiu, A.; Iacolina, M. N.; Melis, A.; Nasir, F. T.; Orlati, A.; Perrodin, D.; Poppi, S.; Trois, A.; Vacca, V.; Zanichelli, A.; Bachetti, M.; Buttu, M.; Comoretto, G.; Concu, R.; Fara, A.; Gaudiomonte, F.; Loi, F.; Migoni, C.; Orfei, A.; Pilia, M.; Bolli, P.; Carretti, E.; D'Amico, N.; Guidetti, D.; Loru, S.; Massi, F.; Pisanu, T.; Porceddu, I.; Ridolfi, A.; Serra, G.; Stanghellini, C.; Tiburzi, C.; Tingay, S.; Valente, G.

2017-12-01

part of European networks. As a result, the SRT started to participate (in shared-risk mode) in European VLBI Network (EVN) and Large European Array for Pulsars (LEAP) observing sessions in early 2014. The validation of single-dish operations for the suite of SRT first light receivers and backends continued in the following year, and was concluded with the first call for shared-risk early-science observations issued at the end of 2015. As discussed in the paper, the SRT capabilities were tested (and optimized when possible) for several different observing modes: imaging, spectroscopy, pulsar timing, and transients.

Optimal technology choice and investment timing: A stochastic model of industrial cogeneration vs. heat-only production

International Nuclear Information System (INIS)

Wickart, Marcel; Madlener, Reinhard

2007-01-01

In this paper we develop an economic model that explains the decision-making problem under uncertainty of an industrial firm that wants to invest in a process technology. More specifically, the decision is between making an irreversible investment in a combined heat-and-power production (cogeneration) system, or to invest in a conventional heat-only generation system (steam boiler) and to purchase all electricity from the grid. In our model we include the main economic and technical variables of the investment decision process. We also account for the risk and uncertainty inherent in volatile energy prices that can greatly affect the valuation of the investment project. The dynamic stochastic model presented allows us to simultaneously determine the optimal technology choice and investment timing. We apply the theoretical model and illustrate our main findings with a numerical example that is based on realistic cost values for industrial oil- or gas-fired cogeneration and heat-only generation in Switzerland. We also briefly discuss expected effects of a CO 2 tax on the investment decision

A randomized controlled intervention trial to relieve and prevent neck/shoulder pain

DEFF Research Database (Denmark)

Andersen, Lars L; Jørgensen, Marie B; Blangsted, Anne Katrine

2008-01-01

PURPOSE: The objective of this study is to investigate the effect of three different workplace interventions on long-term compliance, muscle strength gains, and neck/shoulder pain in office workers. METHODS: A 1-yr randomized controlled intervention trial was done with three groups: specific...... resistance training (SRT, n = 180), all-round physical exercise (APE, n = 187), and reference intervention (REF, n = 182) with general health counseling. Physical tests were performed and questionnaires answered at pre-, mid-, and postintervention. The main outcome measures were compliance, changes......: Compliance was highest in SRT but generally decreased over time. SRT and APE caused increased shoulder elevation strength, were more effective than REF to decrease neck pain among those with symptoms at baseline, and prevent development of shoulder pain in those without symptoms at baseline....

Consumer choice behaviour

OpenAIRE

Hansen, Flemming; Percy, Larry; Hallum Hansen, Morten

2004-01-01

The paper is concerned with the measurement of emotions and the study of the role of emotions in consumer choice. Contemporary neurological findings suggest that emotions may play a role in its own right, quite different from the way in which they have been considered in traditional consumer choice behaviour theory. A large-scale study including 800 respondents, covering 64 brands, provide findings on emotional response tendencies for the brands, and relate these to involvement...

Food choice, appetite and physical activity.

Science.gov (United States)

Bellisle, F

1999-09-01

Food choices and diet composition have been studied less often than energy intake in subjects with varying levels of physical activity. The reported effects of exercise on food choices are not fully consistent, especially on the short term. Type of exercise, intensity, duration can affect the results as well as subjects' characteristics (gender, age, previous training and fitness). A crucial role could also be played by psychological (chronic dieting, attitudes toward health and food, long-established food habits and preferences) and social (traditions, food availability, appropriate times and places) factors. In short-term intervention studies, where a meal is ingested a few minutes following a bout of exercise of varying duration and intensity, an increase in CHO intake is most often reported, while increased protein intake is an occasional observation. In long-term (several weeks) training interventions, intake is assessed from dietary records. Again CHO intake is augmented in exercised subjects as compared to controls, while that of saturated fats and cholesterol may also be affected. Epidemiological studies (without dietary or exercise intervention) often report that habitually active persons eat more and ingest more fruits and vegetables than less active peers. It is not known to what extent such food choices are driven by biological needs (e.g. replacement of glycogen) or elicited by social and psychological factors.

Language Choice of Urban Sino-Indians in Kuala Lumpur, Malaysia

Directory of Open Access Journals (Sweden)

Maya Khemlani David

2008-09-01

Full Text Available Language choice in mixed marriages plays a crucial role in language maintenance. It helps in maintaining at least one or two languages from generation to generation. In this study an examination on the language choice of some Sino-Indian Malaysians in Kuala Lumpur, Malaysia, is explored to find out the language choice in a range of domains and with different speech partners. Sino-Indians are the offspring of marriages between Indians and Chinese. There were 30 participants consisting of 14 males and 16 females who took part in the study. A questionnaire consisting of 89 items was administered to the participants who were working or studying in Kuala Lumpur at that time. The findings reveal that language choice in some Sino-Indian families is influenced by factors such as age, domains of communication, attitudes towards the language, and identity. Age plays an important role in lan¬guage choice, particularly in the home domain. Some older Sino-Indian speakers are bilingual in English and Malay, the middle-aged speakers are trilingual and speak more in English and some Tamil and Chinese, and the younger speakers are multilingual but favour the use of English. This study has also examined how the Sino-Indian respondents viewed their dual heritage.

Dynamics of Choice: Relative Rate and Amount Affect Local Preference at Three Different Time Scales

Science.gov (United States)

Aparicio, Carlos F.; Baum, William M.

2009-01-01

To examine extended control over local choice, the present study investigated preference in transition as food-rate ratio provided by two levers changed across seven components within daily sessions, and food-amount ratio changed across phases. Phase 1 arranged a food-amount ratio of 4:1 (i.e., the left lever delivered four pellets and the right…

Influência do tempo de detenção e da taxa de aplicação de lodo na hidrólise e acidogênese de lodo primário Influence of the sludge retention time and sludge application rate on the hydrolysis and acidogenesis of primary sludge

Directory of Open Access Journals (Sweden)

André Luiz da S. S Coelho

2005-06-01

Full Text Available A pesquisa teve, como objetivo principal, a avaliação da influência do tempo de detenção de lodo (TDL, bem como da taxa de aplicação de lodo (TA na hidrólise e acidogênese de lodo primário de uma estação de tratamento de esgotos. Utilizou-se um digestor hidrolítico de lodo (DHL, em escala de bancada, com volume útil de 1,3 L, operado em bateladas seqüenciais, submetido a diferentes valores de TA, expressa como a razão entre a DQO total e a concentração de SSV aplicada por batelada, ao longo de diferentes tempos de detenção do lodo (TDL. Avaliou-se o desempenho do DHL na produção de DQO filtrada e de ácidos voláteis (AGV, bem como as taxas de hidrólise e de acidogênese, para os valores de TA de 1,7, 2,1 e 2,7 gDQOt/gSSV.d . Foi avaliada, também, a composição dos ácidos voláteis (AGV gerados no reator. Os resultados permitiram concluir que a taxa de hidrólise foi satisfatória somente a partir da TA de 2,1 gDQOt/gSSV.d, tendo sido obtido o melhor resultado com a TA de 2,7 gDQOt/gSSV.d. Em todos os ensaios, o maior valor obtido para a taxa de acidogênese ocorreu com tempos de detenção de lodo próximos a dois dias. A produção de AGV foi proporcional à taxa de aplicação de lodo somente durante o período em que a taxa de acidogênese foi ótima, decrescendo com o aumento de TDL. Os principais tipos de ácidos voláteis produzidos foram o acético e o propiônico.The main aim of the research was to evaluate the influence of the sludge retention time (SRT and application rate (AR on hydrolysis and acidogenesis of primary sludge from a sewage treatment plant. The study was carry out using a lab-scale hydrolytic sludge digestor (HSD of 1.3 L useful volume, operated in sequencing batch mode, subjected to different sludge application rates (AR, expressed as the ratio between total COD and VSS concentration applied to each batch, along different sludge retention time (SRT. The values of applied AR expressed as kg COD

Evaluation of factors influencing choice overload: the case of toys category

OpenAIRE

Kyguolienė, Asta; Dromantaitė, Silva

2016-01-01

In modern and developed society it is acceptable to assume that the greater the choice, the better it meets consumers’ needs. Organizations spend a lot of time and investment in order to provide consumers with the most attractive and their wishes satisfying assortment. Almost in every store consumers are offered a large quantity and variety of products. A large assortment most often is considered as competitive advantage, increasing the freedom of choice, flexibility in decision making, savin...

An advanced traveler navigation system adapted to route choice preferences of the individual users

Directory of Open Access Journals (Sweden)

Mahyar Amirgholy

2017-12-01

Full Text Available The majority of existing navigation systems only account for a single aspect of the route choice, like travel time or distance, in finding the optimal route for the trips in the network. In this research, we first identify a range of diverse factors that travelers take into account in their route choice decision in the network. A stated preference survey is conducted to show the heterogeneity in the preferences of users and its dependence to the purpose of the trips over the weekdays and weekends. Interestingly, results of the survey show that road safety is the most influential factor in the route choice decision of the average participants over weekends, exceeding even the travel time, and participants give more importance to the scenic quality of the routes for their weekend trips in comparison to their weekday trips. The results of the second part of the survey also indicate that in 27% of the cases participants choose routes other than the ones suggested by navigation systems, and 33% of the times that they take the suggested routes, they modify these routes according to their own preferences. The partial inability of existing navigation systems to suggest the routes that match the preferences of users can be attributed to ignoring (1 the diversity in influential factors and (2 the heterogeneity in preferences of the users by these systems. We propose a dynamic mixed logit route choice model to include the effects of information and learning to estimate parameters of a multivariable utility function for individual users based on their own historical route choice data over time. Finally, we present the concept of a smart navigation system that can gather the required information from real-time and online sources to suggest the routes that best match the users’ own preferences.

Beyond the Art Lesson: Free-Choice Learning Centers

Science.gov (United States)

Werth, Laurie

2010-01-01

In this article, the author emphasizes that by providing learning centers in the art studio environment and by providing "free-choice time," art educators can encourage and reinforce the natural learning styles of students. Learning centers give elementary students the freedom to pursue individual artistic expression. They give students an…

Soluble Microbial Product Characterization of Biofilm Formation in Bench-Scale

KAUST Repository

Mines, Paul

2012-12-01

The biological process known as activated sludge (AS) in conjunction with membrane separation technology for the treatment of wastewater has been employed for over four decades. While, membrane biological reactors (MBR) are now widely employed, the phenomenon of membrane fouling is still the most significant factor leading to performance decline of MBRs. Although much research has been done on the subject of MBR fouling over the past two decades, many questions remain unanswered, and consensus within the scientific community is rare. However, research has led to one system parameter generally being regarded as a contributor to membrane fouling, extracellular polymeric compounds (EPS). EPS, and more specifically, the soluble fraction of EPS known as soluble microbial products (SMP), must be further investigated in order to better understand membrane fouling. The biological activity and performance of the MBR is affected by myriad operational parameters, which in turn affects the SMP generated. A commonly varied operational parameter is, depending on the specific treatment needs of a MBR, the sludge retention time (SRT). This study aims to characterize the SMP in three bench-scale MBRs as the SRT is gradually lowered. By studying how the SMP change as the operation of the system is altered, greater understanding of how SMP are related to fouling can be achieved. At the onset of the study, a steady state was established in the system with a SRT of 20 days. Upon stabilization of a 20 day SRT, the system was gradually transitioned to a five and a half day SRT, in stepwise adjustments. Initially, both the trans-membrane pressure (TMP) and the SMP concentrations were at relatively low values, indicating the presence of minimal amounts of biofilm on the membrane surfaces. As the system was altered and more activated sludge was wasted from the reactors, the SRT inherently decreased. As the lower SRT was transitioned and established, the data from TMP measurements, as well

Neural Activity Reveals Preferences Without Choices

Science.gov (United States)

Smith, Alec; Bernheim, B. Douglas; Camerer, Colin

2014-01-01

We investigate the feasibility of inferring the choices people would make (if given the opportunity) based on their neural responses to the pertinent prospects when they are not engaged in actual decision making. The ability to make such inferences is of potential value when choice data are unavailable, or limited in ways that render standard methods of estimating choice mappings problematic. We formulate prediction models relating choices to “non-choice” neural responses and use them to predict out-of-sample choices for new items and for new groups of individuals. The predictions are sufficiently accurate to establish the feasibility of our approach. PMID:25729468

Evoked emotions predict food choice.

Science.gov (United States)

Dalenberg, Jelle R; Gutjar, Swetlana; Ter Horst, Gert J; de Graaf, Kees; Renken, Remco J; Jager, Gerry

2014-01-01

In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA) and apply Multinomial Logit Models (MLM) to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively). After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products) for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

Does School Choice Improve Student Performance?

OpenAIRE

Kaja Høiseth Brugård

2013-01-01

This paper studies the relationship between school choice and student performance for high school students in Norway. The analysis exploits both the fact that the degree of school choice formally differs between counties, and detailed information on travelling distances to high schools, which more closely reflects the students' actual school choice possibilities. Information on students' residence, high school location, and the degree of formal school choice is used to estimate the effect on ...

Isolating the delay component of impulsive choice in adolescent rats

Directory of Open Access Journals (Sweden)

Jesse eMcClure

2014-01-01

Full Text Available Impulsive choice — the preference for small immediate rewards over larger delayed rewards — has been linked to various psychological conditions ranging from behavioral disorders to addiction. These links highlight the critical need to dissect the various components of this multifaceted behavioral trait. Delay discounting tasks allow researchers to study an important factor of this behavior: how the subjective value of a rewards changes over a delay period. However, existing methods of delay discounting include a confound of modifying reward sizes during the procedure. Here we present a new approach of using a single constant reward size to assess delay discounting. A complementary approach could hold delay constant and assess the utility of changing quantities of a reward. Isolating these behavioral components can advance our ability to explore the behavioral complexity of impulsive choice. We present the methods for isolating delay in detail, and further capitalize on this method by pairing it with a standard peak interval task to test whether individual variation in delay discounting can be explained by differences in perception of time in male and female adolescent rats. We find that rats that were more precise in discriminating time intervals were also less impulsive in their choice. Our data suggest that differences in timing and delay discounting are not causally related, but instead are more likely influenced by a common factor. Further, the mean-level change in our measure between postnatal day 28 and 42 suggests this test may be capturing a developmental change in this factor. In summary, this new method of isolating individual components of impulsive choice (delay or quantity can be efficiently applied in either adolescent or adult animal models and may help elucidate the mechanisms underlying impulsivity and its links to psychological disorders.

A surgical career for New Zealand junior doctors? Factors influencing this choice.

Science.gov (United States)

Du, Jason; Sathanathan, Janarthanan; Naden, Gill; Child, Stephen

2009-08-07

To discover the level of interest in a surgical career amongst junior doctors and trainee interns in the Auckland region. Secondary aims are to identify the factors that influence career choice as well as the timing of career choice. An anonymous and structured questionnaire was distributed to all trainee interns and junior doctors in their first to fifth postgraduate years in the Auckland region. Questions were based on basic demographics, level of training, career preference and factors from previous experiences in surgery that may have influenced their career choice. Total of 87 replies with 36% expressed interest in surgery whereas 64% were interested in non-surgical specialties. Top three factors influencing career choice were similar in both groups: Lifestyle, career ambitions and family. Personal interest, practical hands-on and positive previous experiences were the top reasons why junior doctors chose surgery. Poor lifestyle, lacking of interest, limited future part-time work and previous negative experiences were the top reasons why junior doctors did not choose surgery. A significantly (pcareers earlier. Career aspirations of New Zealand junior doctors were similar to findings reported overseas. To promote surgery amongst junior doctors and medical students, attention should be paid to the key factors which may influence career choice. By improving working conditions and have better surgical education with good mentoring, team atmosphere and opportunities for early exposure will hopefully allow better recruitment and training of future surgeons.

Measuring strategic control in implicit learning: How and why?

Directory of Open Access Journals (Sweden)

Elisabeth eNorman

2015-09-01

Full Text Available Several methods have been developed for measuring the extent to which implicitly learned knowledge can be applied in a strategic, flexible manner. Examples include generation exclusion tasks in SRT learning (Destrebecqz & Cleeremans, 2001; Goschke, 1998 and 2-grammar classification tasks in AGL (Dienes, Altmann, Kwan, & Goode, 1995; Norman, Price, & Jones, 2011. Strategic control has traditionally been used as a criterion for determining whether acquired knowledge is conscious or unconscious, or which properties of knowledge is consciously available. In this paper I first summarize existing methods that have been developed for measuring strategic control in the SRT and AGL tasks. I then address some methodologial and theoretical questions. Methodological questions concern choice of task, whether the measurement reflects inhibitory control or task switching, and whether or not strategic control should be measured on a trial-by-trial basis. Theoretical questions concern the rationale for including measurement of strategic control, what form of knowledge is strategically controlled, and how strategic control can be combined with subjective awareness measures.

Meta-analysis of choice set generation effects on route choice model estimates and predictions

DEFF Research Database (Denmark)

Prato, Carlo Giacomo

2012-01-01

are applied for model estimation and results are compared to the ‘true model estimates’. Last, predictions from the simulation of models estimated with objective choice sets are compared to the ‘postulated predicted routes’. A meta-analytical approach allows synthesizing the effect of judgments......Large scale applications of behaviorally realistic transport models pose several challenges to transport modelers on both the demand and the supply sides. On the supply side, path-based solutions to the user assignment equilibrium problem help modelers in enhancing the route choice behavior...... modeling, but require them to generate choice sets by selecting a path generation technique and its parameters according to personal judgments. This paper proposes a methodology and an experimental setting to provide general indications about objective judgments for an effective route choice set generation...

The incidence of radiation necrosis following stereotactic radiotherapy for melanoma brain metastases: the potential impact of immunotherapy.

Science.gov (United States)

Kaidar-Person, Orit; Zagar, Timothy M; Deal, Allison; Moschos, Stergios J; Ewend, Matthew G; Sasaki-Adams, Deanna; Lee, Carrie B; Collichio, Frances A; Fried, David; Marks, Lawrence B; Chera, Bhishamjit S

2017-07-01

Stereotactic radiotherapy (SRT) is the standard treatment for patients with limited number of brain metastases. In the past few years, newer immunotherapies (immune checkpoint inhibitors) have been proven to prolong survival in patients with metastatic melanoma. The safety of the combination of SRT and immunotherapy for brain metastases is unknown. We retrospectively identified patients with melanoma brain metastases treated with SRT between 2007 and 2015. Patients who did not have at least 3 months of follow-up with imaging after SRT were excluded from the analysis. Outcomes were compared between patients who were treated with or without immunotherapy. A total of 58 patients were included; of these, 29 were treated with SRT and immunotherapy. MAPK inhibitors (BRAF, MEK inhibitors) were used more often in the immunotherapy group (nine vs. two patients). There was a higher incidence of intracranial complications in patients treated with immunotherapy and SRT. Eight patients had radiation necrosis; all occurred in patients who were treated with immunotherapy. Nine patients had hemorrhage, of which seven occurred in patients who were treated with immunotherapy (P=0.08). However, patients treated with immunotherapy and SRT had a significant overall survival advantage compared with SRT without immunotherapy (15 vs. 6 months, P=0.0013). Patients treated with SRT and immunotherapy have a higher incidence/risk of intracranial complications, but a longer overall survival.

Choice as an engine of analytic thought.

Science.gov (United States)

Savani, Krishna; Stephens, Nicole M; Markus, Hazel Rose

2017-09-01

Choice is a behavioral act that has a variety of well-documented motivational consequences-it fosters independence by allowing people to simultaneously express themselves and influence the environment. Given the link between independence and analytic thinking, the current research tested whether choice also leads people to think in a more analytic rather than holistic manner. Four experiments demonstrate that making choices, recalling choices, and viewing others make choices leads people to think more analytically, as indicated by their attitudes, perceptual judgments, categorization, and patterns of attention allocation. People who made choices scored higher on a subjective self-report measure of analytic cognition compared to whose did not make a choice (pilot study). Using an objective task-based measure, people who recalled choices rather than actions were less influenced by changes in the background when making judgments about focal objects (Experiment 1). People who thought of others' behaviors as choices rather than actions were more likely to group objects based on categories rather than relationships (Experiment 2). People who recalled choices rather than actions subsequently allocated more visual attention to focal objects in a scene (Experiment 3). Together, these experiments demonstrate that choice has important yet previously unexamined consequences for basic psychological processes such as attention and cognition. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Macro-Choices, Micro-Choosers

Science.gov (United States)

MOSAIC, 1975

1975-01-01

The ways in which the world produces, distributes, and consumes its food are as varied as the small societies with which the world's growing billions most closely identify. Making food choices for the world means first understanding the myriad ways in which the world's microcultures make choices for themselves. (BT)

Evaluation of connected vehicle impact on mobility and mode choice

Directory of Open Access Journals (Sweden)

Simon Minelli

2015-10-01

Full Text Available Connected vehicle is emerging as a solution to exacerbating congestion problems in urban areas. It is important to understand the impacts of connected vehicle on network and travel behavior of road users. The main objective of this paper is to evaluate the impact of connected vehicle on the mode choice and mobility of transportation networks. An iterative methodology was used in this paper where demands for various modes were modified based on the changes in travel time between each origin-destination (OD pair caused by introduction of connected vehicle. Then a traffic assignment was performed in a micro-simulation model, which was able to accurately simulate vehicle-to-vehicle communication. It is assumed that vehicles are equipped with a dynamic route guidance technology to choose their own route using real-time traffic information obtained through communication. The travel times obtained from the micro-simulation model were compared with a base scenario with no connected vehicle. The methodology was tested for a portion of Downtown Toronto, Ontario, Canada. In order to quantify changes in mode share with changes in travel time associated with each OD pair, mode choice models were developed for auto, transit, cycling and pedestrians using data mainly from the Transportation Tomorrow Survey. The impact of connected vehicle on mode choice was evaluated for different market penetrations of connected vehicle. The results of this study show that average travel times for the whole auto mode will generally increase, with the largest increase from connected vehicles. This causes an overall move away from the auto mode for high market penetrations if a dynamic route guidance algorithm is implemented.

Socio-demographic and other patient characteristics associated with time between colonoscopy and surgery, and choice of treatment centre for colorectal cancer: a retrospective cohort study

OpenAIRE

Goldsbury, David; Harris, Mark Fort; Pascoe, Shane; Olver, Ian; Barton, Michael; Spigelman, Allan; O'Connell, Dianne

2012-01-01

Objectives To investigate key patient clinical and demographic characteristics associated with time between colonoscopy and surgery, and choice of treatment centre for colorectal cancer (CRC) patients. This will add to the little published research examining the pathway following CRC diagnosis and prior to surgery. Design Retrospective cohort analysis of linked data. Setting A population-based sample of people diagnosed August 2004 to December 2007 in New South Wales, Australia. Participants ...

Rational Choice and Developmental Influences on Recidivism Among Adolescent Felony Offenders.

Science.gov (United States)

Fagan, Jeffrey; Piquero, Alex R

2007-12-01

Recent case law and social science both have claimed that the developmental limitations of adolescents affect their capacity for control and decision making with respect to crime, diminishing their culpability and reducing their exposure to punishment. Social science has focused on two concurrent adolescent developmental influences: the internalization of legal rules and norms that regulate social and antisocial behaviors, and the development of rationality to frame behavioral choices and decisions. The interaction of these two developmental processes, and the identification of one domain of socialization and development as the primary source of motivation or restraint in adolescence, is the focus of this article. Accordingly, we combine rational choice and legal socialization frameworks into an integrated, developmental model of criminality. We test this framework in a large sample of adolescent felony offenders who have been interviewed at six-month intervals for two years. Using hierarchical and growth curve models, we show that both legal socialization and rational choice factors influence patterns of criminal offending over time. When punishment risks and costs are salient, crime rates are lower over time. We show that procedural justice is a significant antecedent of legal socialization, but not of rational choice. We also show that both mental health and developmental maturity moderate the effects of perceived crime risks and costs on criminal offending.

Rational Choice and Developmental Influences on Recidivism Among Adolescent Felony Offenders

Science.gov (United States)

Fagan, Jeffrey; Piquero, Alex R.

2009-01-01

Recent case law and social science both have claimed that the developmental limitations of adolescents affect their capacity for control and decision making with respect to crime, diminishing their culpability and reducing their exposure to punishment. Social science has focused on two concurrent adolescent developmental influences: the internalization of legal rules and norms that regulate social and antisocial behaviors, and the development of rationality to frame behavioral choices and decisions. The interaction of these two developmental processes, and the identification of one domain of socialization and development as the primary source of motivation or restraint in adolescence, is the focus of this article. Accordingly, we combine rational choice and legal socialization frameworks into an integrated, developmental model of criminality. We test this framework in a large sample of adolescent felony offenders who have been interviewed at six-month intervals for two years. Using hierarchical and growth curve models, we show that both legal socialization and rational choice factors influence patterns of criminal offending over time. When punishment risks and costs are salient, crime rates are lower over time. We show that procedural justice is a significant antecedent of legal socialization, but not of rational choice. We also show that both mental health and developmental maturity moderate the effects of perceived crime risks and costs on criminal offending. PMID:20148123

Factors influencing career choices in radiology trainees in Queensland, Australia.

Science.gov (United States)

Ip, S W; Ko, H S; Applegate, K E

2010-04-01

The aim of this study was to investigate factors influencing career choices in radiology trainees. We distributed a 27-question written survey to all radiology registrars in Queensland. The questions investigated whether radiology was their first specialty choice, career satisfaction, ideal working conditions and attitudes regarding having children during the time of training. Forty-four of 51 surveys were returned (86% participation rate, 73% men, P = 0.048055) with 100% reporting a high job satisfaction; 28% of male registrars compared to 8% of female registrars did extra work outside of training to earn extra money (P = 0.000003), and 17% of female registrars took a leave of absence during their training, while no male registrar did (P = 0.087923). Only one female trainee worked part-time (P = 0.272727). In addition, 58% of female registrars planned a pregnancy (P = 0.731789) before completion of training; 83% of women versus 75% of men had no children (P = 0.329263). Only 5% of trainees agreed that it was easy to arrange part-time training, only 14% stated that it was easy to negotiate flexible work schedules and 7% agreed that it was easy to return to work after a period of absence. 'Time spent with immediate family' was rated the most important lifestyle factor, followed by 'work hours' and 'on-call duty'. The least important factors were 'being away from extended family', 'availability of part-time work' and whether 'work was in a rural location'. Overall job satisfaction is high among radiology trainees. Nevertheless, lifestyle factors, particularly those related to work time, are becoming more important for career decisions. This should be taken into account when designing and structuring radiology training to ensure that it is considered an attractive career choice.

The choices before us.

Science.gov (United States)

Streeten, P P

1980-01-01

This introduction is from the 16th World Conference of SID in Colombo, Sri Lanka, August 1979, which addressed the theme of development choices for the 1980's and beyond. Choices may refer to different political, ideological or social systems. Choices may refer to strategies and technical issues, e.g. agriculture vs. industry. A third meaning of choice is implicit in the idea of a Third World, or alternative, method of development. The third meaning implies a rejection of Western institutions, values, and standards. In the past, the transfer of Western or in this case Northern, institutions and standards has disappointed and created obstacles to development. The rapid rate of population growth forces choices of population control and resource management. Common themes of development have emerged from conference discussions: the need to build development efforts on indigenous values; the need for new institutions both at the sub-national and at the super-national level; and, the need to adjust to inevitable changes rationally and with foresight. The nation state is too large for many functions that are better decentralized and left to village or district administrations, yet it is too small to respond to global challenges and environmental risks like harvest failure, credit risks, marketing risks, failure of supplies. The interests of the state are not identical with those of society or particular groups in society.

Evoked Emotions Predict Food Choice

OpenAIRE

Dalenberg, Jelle R.; Gutjar, Swetlana; ter Horst, Gert J.; de Graaf, Kees; Renken, Remco J.; Jager, Gerry

2014-01-01

In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well ...

A constraints-induced model of park choice

NARCIS (Netherlands)

Stemerding, M.P.; Oppewal, H.; Timmermans, H.J.P.

1999-01-01

Conjoint choice models have been used widely in the consumer-choice literature as an approach to measure and predict consumer-choice behavior. These models typically assume that consumer preferences and choice rules are independent from any constraints that might impact the behavior of interest.

Incorporating Latent Variables into Discrete Choice Models - A Simultaneous Estimation Approach Using SEM Software

Directory of Open Access Journals (Sweden)

Dirk Temme

2008-12-01

Full Text Available Integrated choice and latent variable (ICLV models represent a promising new class of models which merge classic choice models with the structural equation approach (SEM for latent variables. Despite their conceptual appeal, applications of ICLV models in marketing remain rare. We extend previous ICLV applications by first estimating a multinomial choice model and, second, by estimating hierarchical relations between latent variables. An empirical study on travel mode choice clearly demonstrates the value of ICLV models to enhance the understanding of choice processes. In addition to the usually studied directly observable variables such as travel time, we show how abstract motivations such as power and hedonism as well as attitudes such as a desire for flexibility impact on travel mode choice. Furthermore, we show that it is possible to estimate such a complex ICLV model with the widely available structural equation modeling package Mplus. This finding is likely to encourage more widespread application of this appealing model class in the marketing field.