873 research outputs found

    Time of Day and Age Differences in the Components of Working Memory

    Get PDF
    The present study examined the effects of time of day on short-term memory efficiency in older and younger adults. Forty-five young (18-35 years of age) and thirty-six older (over 60 years of age) adults were selected for participation. Subjects were tested individually at 0900 hrs, 1400 hrs or 2000 hrs. Two measures of memory scanning and three measures of memory span were employed. Memory scan measures required subjects to scan working memory for sets of 2, 3 or 4 digits or words. Memory span measures included digit span, word span, and sentence span. The digit and word span measures were the largest list of digits or words the subject could repeat without error. The sentence span measure required the subject to read sentences aloud and remember the last word in each sentence. Sentence span was considered the largest set of last words the subject was able to repeat in order. Results revealed no effect of time of day or age on slopes for word scanning. Analysis of the digit scanning task revealed that slopes decreased across time of day, indicating that subjects scanned working memory faster when tested at 2000 hrs than at either 1400 hrs or 0900 hrs. Results of the memory span analysis revealed no effects on digit span. However, younger adults had larger word spans and sentence spans than older adults. The present results replicate previous work indicating that the rate of memory scanning for digits improves across time of day (Anderson et al., 1988). No effects were observed when words were used as stimulus materials. The absence of any age differences in memory scanning is inconsistent with previous research (Salthouse & Somberg, 1982) suggesting that a larger number of subjects should be tested to examine this result further. The age differences in memory span observed in the present study are consistent with Light and Anderson (1985) suggesting that working memory processes are less efficient in older adults. The lack of any interaction between age and time of day suggests that circadian variations do not differentially affect younger and older adults

    The Effects of Training Designed to Accelerate Piagetian Conservation in Children on WISC Subtest Scores

    Get PDF
    The purpose of this study was to test experimentally for generalization effects to certain WISC subtests from training designed to accelerate Piagetian conservation in children. Forty-five subjects were randomly selected for participation in this study, which involved a pretest-posttest control group design. All subjects were pretested on a Conservation Test and on the Information, Arithmetic, Picture Arrangement, and Object Assembly subtests from the WISC. Subjects found to be conservers on the Conservation pretest were excluded from the study. Subjects from the experimental group found to be non-conservers on the Conservation pretest were taught conservation principles using sever al different tasks adapted from Piaget\u27s experiments. Following the instructional periods, all subjects were posttested using the same measures used for pretesting. The results indicated that Piagetian conservation can be experimentally induced in previously non-conserving children, but there was no significant generalization from the induced conservation to the WISC subtests

    Programmed Interpersonal Relations Training for High School Students

    Get PDF
    Th e purpose of this study was to test the effectiveness of the Basic Interpersonal Relations program as a facilitator of interpersonal relations for high school students. Three intact classes of high school introductory psychology students were used to contrast the effectiveness of the Basic Interpersonal Relations program as shown by the experimental group with a treatment-control group receiving didactic instruction, and with a no-treatment control group. All subjects were pretested with the following instruments: Attitude Toward Others Scale (MMPI), Attitude Toward Self Scale (MMPI), Rotter\u27s Internal- External Control Scale, and an achievement test based on the content of the Basic Interpersonal Relations program. Following pretesting the experimental group began training using the Basic Interpersonal Relations program. While the experimental group received training using the Basic Interpersonal Relations program, the treatment-control group received an equal amount and distribution of time in interpersonal relations training based on the Effectiveness Training principles of Dr. Thomas Gordon. The no-treatment control group participated in their regularly scheduled psychology class. At the conclusion of training, all subjects were posttested using the same measures used for pretesting. In addition, a student opinion survey was administered to the experimental and treatment-control groups subjects, and a parent questionnaire was mailed to the parents of all subjects. The results of the study were not conclusive. Some support was indicated for the effectiveness of the Basic Interpersonal Relations program as a facilitator of interpersonal relations of high school students by the results of the parent questionnaire, the student opinion survey, and the Basic Interpersonal Relations program achievement test. No significance was obtained using the Attitude Toward Self Scale, Attitude Toward Others Scale, and the Internal-External Control Scale. Further research is needed to clarify the effectiveness of the Basic Interpersonal Relations program for use with high school students

    IGF paracrine and autocrine interactions between conceptus and oviduct.

    Get PDF
    Development in vitro is influenced by embryo density, serum, somatic cell co-culture and the production of \u27embryotrophic\u27 paracrine and autocrine factors. Research in our laboratory has focussed principally on the insulin-like growth factor (IGF) family. We have demonstrated that pre-attachment bovine and ovine embryos express mRNAs encoding a number of growth factor ligand and receptor genes including all members of the IGF ligand and receptor family throughout this developmental interval. In addition, early embryos express mRNAs encoding IGF-binding proteins (IGFBPs) 2-5 from the one-cell to the blastocyst stage and IGFBP5 mRNA at the blastocyst stage. Cultured bovine blastocysts release up to 35 pg per embryo in 24 h, whereas release of IGF-I was below detectable values. Analysis extended to bovine oviductal cultures has also demonstrated that mRNAs encoding these IGF family members are present throughout an 8 day culture period. Transcripts encoding IGFBPs 2-6 were also present. Release of both IGFs was recorded over an 8 day culture period. IGF-II release was significantly greater than that observed for IGF-I. Therefore, the IGFs are present throughout the maternal environment during early embryo development. The oocyte, within the follicle, is held in an environment high in IGFs and IGFBPs. The zygote, after fertilization, is maintained in an IGF-rich environment while free-living in the oviduct and the uterus. This review is focused on the IGF family and IGFBPs and their roles in enhancing development up to the blastocyst stage

    A novel technique of extracting UCN lifetimes from storage bottle measurements dominated by scattering losses

    Full text link
    Neutron lifetime is a critical parameter in the Standard Model. Its measurements using, particularly, the beamline and ultracold neutron storage techniques reveals serious tension. The status of the tension between various measurements have been presented, in light of the insights provided by the β\beta-decay correlation measurements. When ultracold neutrons are stored in material bottles, they can be lost to various processes, such as β\beta-decay and up-scattering on material walls. Here, we revisit the lifetime measurement in a material storage bottle, dominated by losses from scattering off the walls of the storage chamber. The neutron energy spectra and its associated uncertainties were, for the first time, well characterized. Such models have been used in the extraction of mean time between wall bounces, which is a key parameter for neutron storage disappearance experiments in search of neutron oscillation. A comparison between the loss model and the number of neutrons stored in a single chamber, used for the neutron electric dipole moment search, allowed us to extract a neutron lifetime of τn∗=879 (+158/−78)stat. (+230/−114)sys. s  (68.3% C.I.)\tau^*_n=879~({+158}/{-78})_{\text{stat.}}~(+230/-114)_{\text{sys.}}~\text{s~~(68.3\% C.I.)}. Though the uncertainty on this lifetime is not competent with currently available measurements, the highlight of this work is that, we precisely identify the systematic sources of uncertainty that contribute to the neutron lifetime measurements in material storage bottles, namely from the uncertainty in the energy spectra, as well as the storage chamber parameters of Fermi potential and loss per bounce parameter. In doing so, we finally highlight the underestimation of the uncertainties in the previous Monte Carlo simulations of experiments using ultracold neutron storage in material bottles.Comment: 20 pages, 7 figures, 4 tables. Long unedited version, with extra details. This is an independent analysis, and not a part of nEDM@PSI collaboratio

    Effects of circadian rhythm phase alteration on physiological and psychological variables: Implications to pilot performance (including a partially annotated bibliography)

    Get PDF
    The effects of environmental synchronizers upon circadian rhythmic stability in man and the deleterious alterations in performance and which result from changes in this stability are points of interest in a review of selected literature published between 1972 and 1980. A total of 2,084 references relevant to pilot performance and circadian phase alteration are cited and arranged in the following categories: (1) human performance, with focus on the effects of sleep loss or disturbance and fatigue; (2) phase shift in which ground based light/dark alteration and transmeridian flight studies are discussed; (3) shiftwork; (4)internal desynchronization which includes the effect of evironmental factors on rhythmic stability, and of rhythm disturbances on sleep and psychopathology; (5) chronotherapy, the application of methods to ameliorate desynchronization symptomatology; and (6) biorythm theory, in which the birthdate based biorythm method for predicting aircraft accident susceptability is critically analyzed. Annotations are provided for most citations

    Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015

    Get PDF
    The third International Exercise-Associated Hyponatremia (EAH) Consensus Development Conference convened in Carlsbad, California in February 2015 with a panel of 17 international experts. The delegates represented 4 countries and 9 medical and scientific sub-specialties pertaining to athletic training, exercise physiology, sports medicine, water/sodium metabolism, and body fluid homeostasis. The primary goal of the panel was to review the existing data on EAH and update the 2008 Consensus Statement.1 This document serves to replace the second International EAH Consensus Development Conference Statement and launch an educational campaign designed to address the morbidity and mortality associated with a preventable and treatable fluid imbalance. The following statement is a summary of the data synthesized by the 2015 EAH Consensus Panel and represents an evolution of the most current knowledge on EAH. This document will summarize the most current information on the prevalence, etiology, diagnosis, treatment and prevention of EAH for medical personnel, athletes, athletic trainers, and the greater public. The EAH Consensus Panel strove to clearly articulate what we agreed upon, did not agree upon, and did not know, including minority viewpoints that were supported by clinical experience and experimental data. Further updates will be necessary to both: (1) remain current with our understanding and (2) critically assess the effectiveness of our present recommendations. Suggestions for future research and educational strategies to reduce the incidence and prevalence of EAH are provided at the end of the document as well as areas of controversy that remain in this topic. [excerpt

    Strongly correlated photons on a chip

    Full text link
    Optical non-linearities at the single-photon level are key ingredients for future photonic quantum technologies. Prime candidates for the realization of strong photon-photon interactions necessary for implementing quantum information processing tasks as well as for studying strongly correlated photons in an integrated photonic device setting are quantum dots embedded in photonic crystal nanocavities. Here, we report strong quantum correlations between photons on picosecond timescales. We observe (a) photon antibunching upon resonant excitation of the lowest-energy polariton state, proving that the first cavity photon blocks the subsequent injection events, and (b) photon bunching when the laser field is in two-photon resonance with the polariton eigenstates of the second Jaynes-Cummings manifold, demonstrating that two photons at this color are more likely to be injected into the cavity jointly, than they would otherwise. Together,these results demonstrate unprecedented strong single-photon non-linearities, paving the way for realizing a single-photon transistor or a quantum optical Josephson interferometer
    • …
    corecore