Processing speed, executive function, and age differences in remembering and knowing.

A group of young (n = 52, M = 23.27 years) and old (n = 52, M = 68.62 years) adults studied two lists of semantically unrelated nouns. For one list a time of 2 s was allowed for encoding, and for the other, 5 s. A recognition test followed where participants classified their responses according to Gardiner's (1988) remember-know procedure. Age differences for remembering and knowing were minimal in the faster 2-s encoding condition. However, in the longer 5-s encoding condition, younger persons produced significantly more remember responses, and older adults a greater number of know responses. This dissociation suggests that in the longer encoding condition, younger adults utilized a greater level of elaborative rehearsal governed by executive processes, whereas older persons employed maintenance rehearsal involving short-term memory. Statistical control procedures, however, found that independent measures of processing speed accounted for age differences in remembering and knowing and that independent measures of executive control had little influence. The findings are discussed in the light of contrasting theoretical accounts of recollective experience in old age

Utilization of cognitive support in episodic free recall as a function of apolipoprotein E and vitamin B12 or folate among adults aged 75 years and older

Apolipoprotein E (APOE), vitamin B12, and folate were examined in relation to free recall among 167 community-based older adults. Cognitive support at encoding and retrieval was also taken into account. Participants were classified as APOE e4 or non-e4 allele carriers and as either low or normal vitamin B12 or folate status. A significant association was identified between low vitamin B12 and the e4 genotype in respect to free recall, but only in circumstances of low cognitive support. This result remained after removing dementia cases that occurred up to 6 years after testing. A similar, but nonsignificant, trend was evident in relation to folate. The research is discussed with reference to vulnerability models and genetic influences on brain reserves

Longitudinal evidence of the impact of normal thyroid stimulating hormone variations on cognitive functioning in very old age

The purpose of this study was to examine longitudinal associations among thyroid stimulating hormone (TSH) levels and cognitive performance. Data collected at the first three assessment times, approximately 3 years apart, are reported for the survivors (n=45) from a previously published cross-sectional study. Participants were aged 75–93 years at baseline, and data reported were collected in the Kungsholmen Project, a longitudinal project investigating aging and dementia. Analyses revealed that although declining verbal fluency and visuospatial abilities were accompanied by simultaneously declining TSH levels, the pattern of cross-sectional and longitudinal results are interpreted such that declining TSH levels may have caused episodic memory deficits later on. These results were obtained in the examination of 6-year but not 3-year change, and after removal of the cognitive variation associated with depressive mood symptoms

Observations of Xyleborus affinis Eichhoff (Coleoptera:Curculionidae:Scolytinae) in Central Michigan

Xyleborus affinis Eichhoff colonized wind thrown timber in the moist floodplain habitats of Central Michigan. Single adult females constructed a complex gallery system consisting of phloem–sapwood interface tunnels and sapwood tunnels. An average of 24 progeny adults and a sex ratio of 14 females to 1 male were found in mature galleries after the first of September

Gallery Characteristics and Life History of the Ambrosia Beetle Trypodendron betulae (Coleoptera: Curculionidae: Scolytinae) in Birch

Trypodendron betulae Swaine distributed attack entrance holes uniformly over the surface of standing stressed sub-canopy birch trees. Male and female pairs constructed galleries consisting of an entrance tunnel about 20 mm in length and then primary and secondary lateral tunnels averaging between 16 and 23 mm in length into the sapwood. Egg niches were constructed in the lateral tunnels after the symbiotic fungus was established in the galleries. Larvae enlarged the niches into cradles. Pupae and eventually teneral adults developed in the cradles. The sex ratio of resulting progeny adults was approximately one to one, and they emerged from galleries in September to overwinter in the litter

Adjusting crop acreages for war production to the soil resources of Iowa

To some people soil conservation is a peacetime luxury; to others it is a first essential of land use. Some say, We are at war now, what does soil matter? Plow it up. Others say, For many years we have been learning conservation; we must not now throwaway our gains. Both attitudes are right if we distinguish between soils which are subject to serious erosion and those which are not, but they are wrong when applied to all soils without regard to their differences. Actually, we face the necessity of exploiting our soils to the point where we will obtain the most food and raw materials over the next 3 to 5 years. We face a serious food shortage in terms of\u27 the needs of our armed forces, our civilian population, our allies and the hungry masses which will soon be freed from tyranny. To meet these needs we should produce the maximum amount of feeds and food products required. We also need to adjust our diets to consume more of those foods which yield the most nourishment per acre

Intra-individual reaction time variability and all-cause mortality over 17 years: A community-based cohort study

Background: very few studies have examined the association between intra-individual reaction time variability and subsequent mortality. Furthermore, the ability of simple measures of variability to predict mortality has not been compared with more complex measures. Method: a prospective cohort study of 896 community-based Australian adults aged 70+ were interviewed up to four times from 1990 to 2002, with vital status assessed until June 2007. From this cohort, 770–790 participants were included in Cox proportional hazards regression models of survival. Vital status and time in study were used to conduct survival analyses. The mean reaction time and three measures of intra-individual reaction time variability were calculated separately across 20 trials of simple and choice reaction time tasks. Models were adjusted for a range of demographic, physical health and mental health measures. Results: greater intra-individual simple reaction time variability, as assessed by the raw standard deviation (raw SD), coefficient of variation (CV) or the intra-individual standard deviation (ISD), was strongly associated with an increased hazard of all-cause mortality in adjusted Cox regression models. The mean reaction time had no significant association with mortality. Conclusion: intra-individual variability in simple reaction time appears to have a robust association with mortality over 17 years. Health professionals such as neuropsychologists may benefit in their detection of neuropathology by supplementing neuropsychiatric testing with the straightforward process of testing simple reaction time and calculating raw SD or CV

The physiology and genetics of stomatal adjustment under fluctuating and stressed environments

Stomata are pores in the leaf that allow gas exchange where water vapor leaves the plant and carbon dioxide enters. Under natural condition, plants always experience at a fluctuating light regime (shade-/sun-fleck) and due to global climate change, occasionally extreme high temperature and CO2 enrichment will be inevitable occurred, which dramatically affects stomatal response, and trade-off between water-use efficiency and photosynthesis. Response of stomata to fluctuating and stressed environments determines optimized strategy of plants directing to water save or photosynthesis. Dynamic adjustments of stomata play an equivalent role as steady-state stomatal characteristics. Evolutionary approach indicated that stomatal-dynamic adjustments interacting with historical environments or life histories could be genetically controlled and environmentally selected. In this article, we reviewed physiological response of stomatal dynamic to changing enironments including our previous works, and discussed the possibility of genetic improvements on stomatal adjustments by estimating broad-sense heritability and SNP heritability of stomatal pattern. To gain insight into the framework of stomatal genetics, we highlighted the importance of combining multidisciplinary techniques, such as mathematic modeling, quantitative genetics, molecular biology and equipments developments

Geographical variation in certification rates of blindness and sight impairment in England, 2008-2009

To examine and interpret the variation in the incidence of blindness and sight impairment in England by PCT, as reported by the Certificate of Vision Impairment (CVI). Design: Analysis of national certification data. Setting: All Primary Care Trusts, England. Participants: 23 773 CVI certifications issued from 2008 to 2009. Main Outcome measures: Crude and Age standardised rates of CVI data for blindness and sight loss by PCT. Methods: The crude and age standardised CVI rates per 100 000 were calculated with Spearman's rank correlation used to assess whether there was any evidence of association between CVI rates with Index of Multiple Deprivation (IMD) and the Programme Spend for Vision. Results: There was high-level variation, almost 11-fold (coefficient of variation 38%) in standardised CVI blindness and sight impairment annual certification rates across PCTs. The mean rate was 43.7 and the SD 16.7. We found little evidence of an association between the rate of blindness and sight impairment with either the IMD or Programme Spend on Vision. Conclusions: The wide geographical variation we found raises questions about the quality of the data and whether there is genuine unmet need for prevention of sight loss. It is a concern for public health practitioners who will be interpreting these data locally and nationally as the CVI data will form the basis of the public health indicator ‘preventable sight loss’. Poor-quality data and inadequate interpretation will only create confusion if not addressed adequately from the outset. There is an urgent need to address the shortcomings of the current data collection system and to educate all public health practitioners