The nature of science as a foundation for fostering a better understanding of evolution

Misunderstandings of the nature of science (NOS) contribute greatly to resistance to evolutionary theory especially among non-scientific audiences. Here we delineate three extended instructional examples that make extensive use of NOS to establish a foundation upon which to more successfully introduce evolution. Specifically, these instructional examples enable students to consider evolutionary biology using NOS as a lens for interpretation of evolutionary concepts. We have further found, through our respective research efforts and instructional experiences, that a deep understanding of NOS helps students understand and accept the scientific validity of evolution and, conversely, that evolution provides an especially effective context for helping students and teachers to develop a deep understanding of the nature of science. Based on our research and instructional experiences, we introduce six key factors necessary for enhanced instructional success in teaching evolution. These factors are: (1) foster a deep understanding of NOS; (2) use NOS as a lens for evolution instruction; (3) explicitly compare evolution to alternative explanations; (4) focus on human evolution (where possible); (5) explicitly recognize the power of historical inference and (6) use active, social learning. Finally, we elaborate and ground these key factors in supporting literature

Intersubject Regularity in the Intrinsic Shape of Human V1

Previous studies have reported considerable intersubject variability in the three-dimensional geometry of the human primary visual cortex (V1). Here we demonstrate that much of this variability is due to extrinsic geometric features of the cortical folds, and that the intrinsic shape of V1 is similar across individuals. V1 was imaged in ten ex vivo human hemispheres using high-resolution (200 μm) structural magnetic resonance imaging at high field strength (7 T). Manual tracings of the stria of Gennari were used to construct a surface representation, which was computationally flattened into the plane with minimal metric distortion. The instrinsic shape of V1 was determined from the boundary of the planar representation of the stria. An ellipse provided a simple parametric shape model that was a good approximation to the boundary of flattened V1. The aspect ration of the best-fitting ellipse was found to be consistent across subject, with a mean of 1.85 and standard deviation of 0.12. Optimal rigid alignment of size-normalized V1 produced greater overlap than that achieved by previous studies using different registration methods. A shape analysis of published macaque data indicated that the intrinsic shape of macaque V1 is also stereotyped, and similar to the human V1 shape. Previoud measurements of the functional boundary of V1 in human and macaque are in close agreement with these results

Exo-zodiacal disk mapper: a space interferometer to detect and map zodiacal disks around nearby stars

We propose a concept for a space mission designed to make a survey of potential zodiacal dust disks around nearby stars in the mid-IR. We show that a 10-meter baseline nulling interferometer with two 0.6-meter apertures located in a 1 X 1 AU heliocentric orbit would allow for the survey of about 400 stars in the solar neighborhood and permit a first order determination of the disk inclination and of the dust density and temperature radius dependence. The high dynamic range of the instrument may also be used to study an additional astrophysical phenomena. Beyond its own scientific merit, such a mission would also serve as a technological precursor to a larger interferometer of the type being considered for the detection of earth-like planets

Blood acetylcholinesterase and butyrylcholinesterase as biomarkers of cholinesterase depression among pesticide handlers

Agricultural pesticide handlers are at an elevated risk for overexposure to organophosphate (OP) pesticides, but symptoms can be difficult to recognize, making biomarkers invaluable for diagnosis. Occupational monitoring programs for cholinesterase depression generally rely on measuring activity of either of two common blood cholinesterases which serve as proxy measurements for nervous-system acetylcholinesterase activity: red blood cell acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE). These biomarkers, however, may be affected differentially by some OPs and the relationship between them has not been well characterized. We aim to determine the association between blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity levels and assess whether they produce comparable classifications of clinical cholinesterase depression among organophosphate pesticide handlers

Automated Segmentation of Hippocampal Subfields From Ultra-High Resolution In Vivo MRI

Recent developments in MRI data acquisition technology are starting to yield images that show anatomical features of the hippocampal formation at an unprecedented level of detail, providing the basis for hippocampal subfield measurement. However, a fundamental bottleneck in MRI studies of the hippocampus at the subfield level is that they currently depend on manual segmentation, a laborious process that severely limits the amount of data that can be analyzed. In this article, we present a computational method for segmenting the hippocampal subfields in ultra-high resolution MRI data in a fully automated fashion. Using Bayesian inference, we use a statistical model of image formation around the hippocampal area to obtain automated segmentations. We validate the proposed technique by comparing its segmentations to corresponding manual delineations in ultra-high resolution MRI scans of 10 individuals, and show that automated volume measurements of the larger subfields correlate well with manual volume estimates. Unlike manual segmentations, our automated technique is fully reproducible, and fast enough to enable routine analysis of the hippocampal subfields in large imaging studies.National Institutes of Health (U.S.) (NIH NCRR; Grant number: P41-RR14075)National Institutes of Health (U.S.) (Grant R01 RR16594-01A1)National Institutes of Health (U.S.) (Grant NAC P41-RR13218)Biomedical Informatics Research Network (BIRN002)Biomedical Informatics Research Network (U24 RR021382)National Institute of Biomedical Imaging and Bioengineering (U.S.) (R01 EB001550)National Institute of Biomedical Imaging and Bioengineering (U.S.) (R01EB006758)National Institute of Biomedical Imaging and Bioengineering (U.S.) (NAMIC U54-EB005149)National Institute of Neurological Disorders and Stroke (U.S.) (R01 NS052585-01)National Institute of Neurological Disorders and Stroke (U.S.) (R01 NS051826)Mental Illness and Neuroscience Discovery (MIND) InstituteEllison Medical Foundation (Autism & Dyslexia Project

Extreme Ultraviolet Quasar Colours from GALEX Observations of the SDSS DR14Q Catalogue

The rest-frame far to extreme ultraviolet (UV) colour–redshift relationship has been constructed from data on over 480,000 quasars carefully cross-matched between SDSS Data Release 14 and the final GALEX photometric catalogue. UV matching and detection probabilities are given for all the quasars, including dependencies on separation, optical brightness, and redshift. Detection limits are also provided for all objects. The UV colour distributions are skewed redward at virtually all redshifts, especially when detection limits are accounted for. The median GALEX far-UV minus near-UV (FUV − NUV) colour–redshift relation is reliably determined up to z ≈ 2.8, corresponding to rest-frame wavelengths as short as 400 Å. Extreme UV (EUV) colours are substantially redder than found previously, when detection limits are properly accounted for. Quasar template spectra were forward modelled through the GALEX bandpasses, accounting for intergalactic opacity, intrinsic reddening, and continuum slope variations. Intergalactic absorption by itself cannot account for the very red EUV colours. The colour–redshift relation is consistent with no intrinsic reddening, at least for SMC-like extinction. The best model fit has a FUV continuum power-law slope αν, FUV = −0.34 ± 0.03 consistent with previous results, but an EUV slope αν, EUV = −2.90 ± 0.04 that is much redder and inconsistent with any previous composite value (all ≳ −2.0). The EUV slope difference can be attributed in part to the tendency of previous studies to preferentially select UV brighter and bluer objects. The weak EUV flux suggests quasar accretion disc models that include outflows such as disc winds

Structural and immunochemical characterization of the type VIII group B Streptococcus capsular polysaccharide.

The type VIII capsular polysaccharide has been isolated and purified from a newly described strain of group B Streptococcus which is a leading cause of sepsis and neonatal meningitis in Japan. The polysaccharide contains D-glucose, D-galactose, L-rhamnose, and sialic acid in the molar ratio 1:1:1:1. By means of high resolution 1H nuclear magnetic resonance (1H NMR), 13C NMR, and homo- and heterocorrelated NMR, the repeating unit structure of the type VIII polysaccharide was delineated as the following, [formula: see text] Enzymatic studies established this polysaccharide as the first from which sialic acid, linked to a branched beta-D-galactopyranosyl residue, is known to be removed by bacterial neuraminidase

Reduced Purkinje cell number in essential tremor : a postmortem study

Background: Clinical and functional imaging evidence suggests that cerebellar dysfunction occurs in essential tremor (ET). In recent postmortem studies, we documented increased numbers of torpedoes (Purkinje cell axonal swellings) in ET patients without Lewy bodies. Purkinje cell loss, however, has never been rigorously assessed. Objective: To quantitatively assess the number of Purkinje cells in brains of ET patients and similarly aged controls. Methods: Postmortem cerebellar tissue was available in 14 ET cases (6 with Lewy bodies and 8 without Lewy bodies) and 11 controls. Calbindin immunohistochemistry was performed on paraffin sections of the cerebellum. Images were digitally recorded and blinded measurements of the number of Purkinje cells per millimeter of cell layer (linear density) were made. Results: Purkinje cell linear density was inversely correlated with age (r=-0.53, P=.006) and number of torpedoes (r=-0.42, P=.04). Purkinje cell linear density differed by diagnosis (mean [SD], controls, 3.46 [1.27] cells/mm; ET cases with Lewy bodies, 3.33 [1.06] cells/mm; and ET cases without Lewy bodies, 2.14 [0.82] cells/mm; P=.04), with the most significant difference between ET cases without Lewy bodies and controls, where the reduction was 38.2% (P=.04). In an adjusted linear regression analysis that compared ET cases without Lewy bodies with controls, decreased linear density (outcome variable) was associated with ET (β=.56, P=.03). Conclusions: We demonstrated a reduction in Purkinje cell number in the brains of patients with ET who do not have Lewy bodies. These data further support the view that the cerebellum is anatomically, as well as functionally, abnormal in these ET cases