2,262 research outputs found

    A Threat to Geoscience Education: Creationist Anti-Evolution Activity in Canada

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    The rejection of biological and geological evolution is a pervasive problem in science education. Recent events in the United States have brought anti-evolution activity to the forefront in media coverage of science education, but Canadians are often unaware that such creationist, anti-evolution activity is present in Canada as well. In this article, various foreign and Canadian-based anti-evolution efforts that threaten biology and geoscience education are discussed. These creationist organizations and their activities may adversely influence Canadian science curricula and public understanding of evolution and science in general. SOMMAIRE Je rejet de l'idée d'évolution biologique et géologique est un problème généralisé auquel est confronté l'enseignement des sciences. Récemment, aux États-Unis, certains événements ont porté l'activisme anti-évolution à l'avant-scène de la couverture médiatique de l'enseignement des sciences, mais ici au Canada, il est fréquent que les Canadiens ne soient pas conscients qu'un tel mouvement créationniste et anti-évolution existe. Le présent article décrit divers mouvements créationnistes et anti-évolution, d'origine étrangère et canadienne, qui menace l'enseignement de la biologie et des sciences de la Terre. Les efforts de ces organisations créationnistes peuvent avoir un effet préjudiciable sur le contenu des programmes d'enseignement des sciences et sur la compréhension du public de l'évolution et des sciences en général

    Immediate post-isometric exercise cardiovascular responses are associated with training-induced resting systolicblood pressure reductions

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    Purpose: The purpose of this study was twofold: (1) to investigate the effect of four-weeks of bilateral-leg isometric exercise training on the immediate isometric post-exercise cardiovascular responses, and (2) to ascertain whether any changes in immediate post-exercise cardiovascular responses may be associated with training-induced adaptations in resting blood pressure. Methods: Thirteen normotensive males completed both isometric exercise training (IET) and control conditions, which were separated by 6 weeks. Participants performed a total of twelve training sessions; 4 * 2-minute bilateral-leg isometric exercise bouts separated by 3-minute rest periods, 3 days.wk-1. Results: 4-weeks of bilateral-leg IET resulted in a reduction in resting SBP (120 ± 12 to 115 ± 12 mmHg, p = 0.01). The intercept of the 5-minute post-exercise systolic blood pressure slope was lower (p = 0.015) following the 4-week training intervention. Individual changes in immediate post-exercise response SBP were also significantly correlated with reductions in resting SBP following 4-weeks of training. There were significant differences in the slopes of the first vs. final post-exercise BRS response (p = 0.009), and the intercepts of the HRR slopes (p = 0.04) recorded during the 5-minute post-exercise periods Conclusions: Four weeks of IET altered immediate cardiovascular responses to an individual IET session. Altered immediate responses were also associated with training induced reductions in resting SBP. To our knowledge, this is the first evidence suggesting very short-term (immediate) cardiovascular responses may be important in defining chronic reductions in resting blood pressure following a period of IET

    Tropical–North Pacific Climate Linkages over the Past Four Centuries

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    Analyses of instrumental data demonstrate robust linkages between decadal-scale North Pacific and tropical Indo-Pacific climatic variability. These linkages encompass common regime shifts, including the noteworthy 1976 transition in Pacific climate. However, information on Pacific decadal variability and the tropical high-latitude climate connection is limited prior to the twentieth century. Herein tree-ring analysis is employed to extend the understanding of North Pacific climatic variability and related tropical linkages over the past four centuries. To this end, a tree-ring reconstruction of the December-May North Pacific index (NPI)-an index of the atmospheric circulation related to the Aleutian low pressure cell-is presented (1600-1983). The NPI reconstruction shows evidence for the three regime shifts seen in the instrumental NPI data, and for seven events in prior centuries. It correlates significantly with both instrumental tropical climate indices and a coral-based reconstruction of an optimal tropical Indo-Pacific climate index, supporting evidence for a tropical-North Pacific link extending as far west as the western Indian Ocean. The coral-based reconstruction (1781-1993) shows the twentieth-century regime shifts evident in the instrumental NPI and instrumental tropical Indo-Pacific climate index, and three previous shifts. Changes in the strength of correlation between the reconstructions over time, and the different identified shifts in both series prior to the twentieth century, suggest a varying tropical influence on North Pacific climate, with greater influence in the twentieth century. One likely mechanism is the low-frequency variability of the El Nino-Southern Oscillation (ENSO) and its varying impact on Indo-Pacific climate.</p

    The timing of maternal depressive symptoms and child cognitive development: a longitudinal study.

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    Background: Maternal depression is known to be associated with impairments in child cognitive development, although the effect of timing of exposure to maternal depression is unclear. Methods: Data collected for the Avon Longitudinal Study of Parents and Children, a longitudinal study beginning in pregnancy, included self-report measures of maternal depression the Edinburgh Postnatal Depression Scale, completed on 6 occasions up to 3 years of age, and IQ of the index child (WISC) measured at aged 8 years. We used these data to assign women to 8 groups according to whether depression occurred in the antenatal, postnatal, preschool period, any combination of these times, or not at all. We compared a model comprising all patterns of depression (saturated model) with models nested within this to test whether there is a relationship between depression and child cognitive development and, if so, whether there is a sensitive period. We then investigated the relationship with child IQ for each model, following adjustment for confounders. Results: Six thousand seven hundred and thirty-five of 13,615 children from singleton births (49.5%, of eligible core sample) attended a research clinic at 8 years and completed a WISC with a score ≥ 70. A total of 5,029 mothers of these children had completed mood assessments over the 3 time periods. In unadjusted analyses, all three sensitive period models were as good as the saturated model, as was an accumulation model. Of the sensitive period models, only that for antenatal exposure was a consistently better fit than the accumulation model. After multiple imputation for missing data (to n = 6,735), there was no effect of postnatal depression on child IQ independent of depression at other times [-0.19 IQ points, 95% confidence interval (CI) -1.5 to 1.1 points]. There was an effect of antenatal depression (-3.19 IQ points, 95% CI: -4.33 to -2.06) which attenuated following adjustment (-0.64 IQ points, 95% CI: -1.68 to 0.40). Conclusions: The postnatal period is not a sensitive one for the effect of maternal depression on child cognitive development. © 2011 The Authors. Journal of Child Psychology and Psychiatry

    The safety of isometric exercise: rethinking the exercise prescription paradigm for those with stage 1 hypertension.

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    Few studies have investigated the relative safety of prescribing isometric exercise (IE) to reduce resting blood pressure (BP). This study aimed to ascertain the safety of the hemodynamic response during an IE wall squat protocol.Twenty-six hypertensive (BP of 120-139 mm Hg systolic and/or 80-90 mm Hg diastolic) males (45 ± 8 years; 1.78 ± 0.07 m; 89.7 ± 12.3 kg; mean ± SD), visited the laboratory on 2 separate occasions. Heart rate (HR) and BP were measured at rest and continuously throughout exercise. In visit 1, participants completed a continuous incremental isometric wall squat exercise test, starting at 135° of knee flexion, decreasing by 10° every 2 minutes until 95° (final stage). Exercise was terminated upon completion of the test or volitional fatigue. The relationship between knee joint angle and mean HR was used to calculate the participant-specific knee joint angle required to elicit a target HR of 95% HRpeak. This angle was used to determine exercise intensity for a wall squat training session consisting of 4 × 2 minute bouts (visit 2).Systolic BPs during the exercise test and training were 173 ± 21 mm Hg and 171 ± 19 mm Hg, respectively, (P > .05) and were positively related (r = 0.73, P  .05) and were positively related (r = 0.42, P  250 mm Hg. Diastolic BP values > 115 mm Hg were recorded in 12 participants during the incremental test and 6 participants during the training session. Peak rate pressure product was 20681 ± 3911 mm Hg bpm during the IE test and was lower (18074 ± 3209 mm Hg bpm) during the IE session (P = .002). No adverse effects were reported.Based on the current ACSM guidelines for aerobic exercise termination, systolic BP does not reach the upper limit during IE in this population. Diastolic BP exceeds 115 mm Hg in some during the IE protocol, which may suggest the need to individualise IE training prescription in some with suboptimal BP control. Future research is required to ascertain if IE requires modified BP termination guidelines

    Multiproxy records of climate variability for Kamchatka for the past 400 years

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    International audienceTree rings, ice cores and glacial geologic histories for the past several centuries offer an opportunity to characterize climate variability and to identify the key climate parameters forcing glacier expansions. A newly developed larch ring-width chronology is presented for Kamchatka that is sensitive to past summer temperature variability. This record provides the basis to compare with other proxy records of inferred temperature and precipitation change from ice core and glacier records, and to characterize climate for the region over the past 400 years. Individual low growth years in the larch record are associated with several known and proposed volcanic events that have been observed in other proxy records from the Northern Hemisphere. Comparison of the tree-rings with an ice core record of melt feature index for Kamchatka's Ushkovsky volcano confirms a 1?3 year dating accuracy for this ice core series over the late 18th to 20th centuries. Decadal variations of low summer temperatures (tree-ring record) and high annual precipitation (ice core record) are broadly consistent with intervals of positive mass balance measured and estimated at several glaciers, and with moraine building, provides a basis to interpret geologic glacier records

    Using Whole Mount in situ Hybridization to Link Molecular and Organismal Biology

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    Whole mount in situ hybridization (WISH) is a common technique in molecular biology laboratories used to study gene expression through the localization of specific mRNA transcripts within whole mount specimen. This technique (adapted from Albertson and Yelick, 2005) was used in an upper level undergraduate Comparative Vertebrate Biology laboratory classroom at Syracuse University. The first two thirds of the Comparative Vertebrate Biology lab course gave students the opportunity to study the embryology and gross anatomy of several organisms representing various chordate taxa primarily via traditional dissections and the use of models. The final portion of the course involved an innovative approach to teaching anatomy through observation of vertebrate development employing molecular techniques in which WISH was performed on zebrafish embryos. A heterozygous fibroblast growth factor 8 a (fgf8a) mutant line, ace, was used. Due to Mendelian inheritance, ace intercrosses produced wild type, heterozygous, and homozygous ace/fgf8a mutants in a 1:2:1 ratio. RNA probes with known expression patterns in the midline and in developing anatomical structures such as the heart, somites, tailbud, myotome, and brain were used. WISH was performed using zebrafish at the 13 somite and prim-6 stages, with students performing the staining reaction in class. The study of zebrafish embryos at different stages of development gave students the ability to observe how these anatomical structures changed over ontogeny. In addition, some ace/fgf8a mutants displayed improper heart looping, and defects in somite and brain development. The students in this lab observed the normal development of various organ systems using both external anatomy as well as gene expression patterns. They also identified and described embryos displaying improper anatomical development and gene expression (i.e., putative mutants)
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