2,472 research outputs found
Collections Education: The Extended Specimen and Data Acumen
Biodiversity scientists must be fluent across disciplines; they must possess the quantitative, computational, and data skills necessary for working with large, complex data sets, and they must have foundational skills and content knowledge from ecology, evolution, taxonomy, and systematics. To effectively train the emerging workforce, we must teach science as we conduct science and embrace emerging concepts of data acumen alongside the knowledge, tools, and techniques foundational to organismal biology. We present an open education resource that updates the traditional plant collection exercise to incorporate best practices in twenty-first century collecting and to contextualize the activities that build data acumen. Students exposed to this resource gained skills and content knowledge in plant taxonomy and systematics, as well as a nuanced understanding of collections-based data resources. We discuss the importance of the extended specimen in fostering scientific discovery and reinforcing foundational concepts in biodiversity science, taxonomy, and systematics
New techniques for imaging and analyzing lung tissue.
The recent technological revolution in the field of imaging techniques has provided pathologists and toxicologists with an expanding repertoire of analytical techniques for studying the interaction between the lung and the various exogenous materials to which it is exposed. Analytical problems requiring elemental sensitivity or specificity beyond the range of that offered by conventional scanning electron microscopy and energy dispersive X-ray analysis are particularly appropriate for the application of these newer techniques. Electron energy loss spectrometry, Auger electron spectroscopy, secondary ion mass spectrometry, and laser microprobe mass analysis each offer unique advantages in this regard, but also possess their own limitations and disadvantages. Diffraction techniques provide crystalline structural information available through no other means. Bulk chemical techniques provide useful cross-checks on the data obtained by microanalytical approaches. It is the purpose of this review to summarize the methodology of these techniques, acknowledge situations in which they have been used in addressing problems in pulmonary toxicology, and comment on the relative advantages and disadvantages of each approach. It is necessary for an investigator to weigh each of these factors when deciding which technique is best suited for any given analytical problem; often it is useful to employ a combination of two or more of the techniques discussed. It is anticipated that there will be increasing utilization of these technologies for problems in pulmonary toxicology in the decades to come
Field techniques for rearing and marking mountain pine beetle for use in dispersal studies
Mountain pine beetles, Dendroctonus ponderosae, were marked with fluorescent (DayGlo) powders in vacuum chambers and on powder-covered brood trees in the field for use in release-recapture studies of dispersal behaviour. A large wall tent was used as a field insectary to accelerate late stages of development of large numbers of beetles in naturally infested bolts of lodgepole pine. Up to 28% of the marked beetles which flew were recovered from lethal trap trees. Beetles self-marked on powdered brood trees were captured in barrier traps in predicted proportions
Macrophage Mal1 Deficiency Suppresses Atherosclerosis in Low-Density Lipoprotein Receptor -Null Mice by Activating Peroxisome Proliferator-Activated Receptor-g-Regulated Genes
Cataloged from PDF version of article.Objective-The adipocyte/macrophage fatty acid-binding proteins aP2 (FABP4) and Mal1 (FABP5) are intracellular lipid chaperones that modulate systemic glucose metabolism, insulin sensitivity, and atherosclerosis. Combined deficiency of aP2 and Mal1 has been shown to reduce the development of atherosclerosis, but the independent role of macrophage Mal1 expression in atherogenesis remains unclear.
Methods and Results-We transplanted wild-type (WT), Mal1(-/-), or aP2(-/-) bone marrow into low-density lipoprotein receptor-null (LDLR(-/-)) mice and fed them a Western diet for 8 weeks. Mal1(-/-)-> LDLR(-/-) mice had significantly reduced (36%) atherosclerosis in the proximal aorta compared with control WT -> LDLR(-/-) mice. Interestingly, peritoneal macrophages isolated from Mal1-deficient mice displayed increased peroxisome proliferator-activated receptor-gamma (PPAR gamma) activity and upregulation of a PPAR gamma-related cholesterol trafficking gene, CD36. Mal1(-/-) macrophages showed suppression of inflammatory genes, such as COX2 and interleukin 6. Mal1(-/-)-> LDLR(-/-) mice had significantly decreased macrophage numbers in the aortic atherosclerotic lesions compared with WT -> LDLR(-/-) mice, suggesting that monocyte recruitment may be impaired. Indeed, blood monocytes isolated from Mal1(-/-)-> LDLR(-/-) mice on a high-fat diet had decreased CC chemokine receptor 2 gene and protein expression levels compared with WT monocytes.
Conclusion-Taken together, our results demonstrate that Mal1 plays a proatherogenic role by suppressing PPAR gamma activity, which increases expression of CC chemokine receptor 2 by monocytes, promoting their recruitment to atherosclerotic lesions. (Arterioscler Thromb Vasc Biol. 2011;31:1283-1290.
Easy on that trigger dad: a study of long term family photo retrieval
We examine the effects of new technologies for digital photography on people's longer term storage and access to collections of personal photos. We report an empirical study of parents' ability to retrieve photos related to salient family events from more than a year ago. Performance was relatively poor with people failing to find almost 40% of pictures. We analyze participants' organizational and access strategies to identify reasons for this poor performance. Possible reasons for retrieval failure include: storing too many pictures, rudimentary organization, use of multiple storage systems, failure to maintain collections and participants' false beliefs about their ability to access photos. We conclude by exploring the technical and theoretical implications of these findings
Measurement of the Zero Crossing in a Feshbach Resonance of Fermionic 6-Li
We measure a zero crossing in the scattering length of a mixture of the two
lowest hyperfine states of 6-Li. To locate the zero crossing, we monitor the
decrease in temperature and atom number arising from evaporation in a CO2 laser
trap as a function of magnetic field B. The temperature decrease and atom loss
are minimized for B=528(4) G, consistent with no evaporation. We also present
preliminary calculations using potentials that have been constrained by the
measured zero crossing and locate a broad Feshbach resonance at approximately
860 G, in agreement with previous theoretical predictions. In addition, our
theoretical model predicts a second and much narrower Feshbach resonance near
550 G.Comment: Five pages, four figure
High-Level Expression of Various Apolipoprotein (a) Isoforms by "Transferrinfection". The Role of Kringle IV Sequences in the Extracellular Association with Low-Density Lipoprotein
Characterization of the assembly of lipoprotein(a) [Lp(a)] is of fundamental importance to understanding the biosynthesis and metabolism of this atherogenic lipoprotein. Since no established cell lines exist that express Lp(a) or apolipoprotein(a) [apo(a)], a "transferrinfection" system for apo(a) was developed utilizing adenovirus receptor- and transferrin receptor-mediated DNA uptake into cells. Using this method, different apo(a) cDNA constructions of variable length, due to the presence of 3, 5, 7, 9, 15, or 18 internal kringle IV sequences, were expressed in cos-7 cells or CHO cells. All constructions contained kringle IV-36, which includes the only unpaired cysteine residue (Cys-4057) in apo(a). r-Apo(a) was synthesized as a precursor and secreted as mature apolipoprotein into the medium. When medium containing r-apo(a) with 9, 15, or 18 kringle IV repeats was mixed with normal human plasma LDL, stable complexes formed that had a bouyant density typical of Lp(a). Association was substantially decreased if Cys-4057 on r-apo(a) was replaced by Arg by site-directed mutagenesis or if Cys-4057 was chemically modified. Lack of association was also observed with r-apo(a) containing only 3, 5, or 7 kringle IV repeats without "unique kringle IV sequences", although Cys-4057 was present in all of these constructions. Synthesis and secretion of r-apo(a) was not dependent on its sialic acid content. r-Apo(a) was expressed even more efficiently in sialylation-defective CHO cells than in wild-type CHO cells. In transfected CHO cells defective in the addition of N-acetylglucosamine, apo(a) secretion was found to be decreased by 50%. Extracellular association with LDL was not affected by the carbohydrate moiety of r-apo(a), indicating a protein-protein interaction between r-apo(a) and apoB. These results show that, besides kringle IV-36, other kringle IV sequences are necessary for the extracellular association of r-apo(a) with LDL. Changes in the carbohydrate moiety of apo(a), however, do not affect complex formation
Efficient Estimation of a Semiparametric Characteristic-Based Factor Model of Security Returns
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