1,648 research outputs found
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The Ecology of Information Literacy: Modes of Inquiry, Location, and Assessment in a Biology Department’s Writing Class
Like many universities, the University of Colorado Boulder’s (CU’s) curriculum contains capstone courses enabling undergraduate students to develop skills in employing written communication in post-graduation, professional work. Frequently, capstones focus on writing genres within certain disciplines. Such is the case for one writing class housed within CU’s Department of Ecology and Evolutionary Biology (EBIO 3940: Written Communication in the Sciences). The class adheres with curricular priorities EBIO formulated in response to calls for enhanced STEM learning.1 Building upon the department’s priorities, faculty teaching EBIO 3940 aim for students to move beyond mere grammatical and stylistic correctness into a critical understanding of writing’s purposes within STEM. To build that awareness, many learning activities have been designed to teach students how to extract information from peer-reviewed research reports and critically assess its accuracy, authority, and breadth. However, too few of EBIO 3940’s students were showing prowess in such skills, despite information literacy (IL) sessions. Students were able to perform searches competently, but we noted that they lacked the ability to apply deeper analyses. As noted by Feekery and Emerson, the class was perating under the premise that IL skills and writing skills were largely independent; we were teaching IL as a series of procedures, rather than as concepts deeply enmeshed within writing and reasoning.2 Farrell and Badke similarly call “to position IL as [an] integral part of disciplinary socialization.”3 We saw a need to act toward integrating IL within the students’ STEM education and to guide them toward enculturation in their disciplines.4 Once socialized into disciplinary practices in the sciences, “good writers will clearly and concisely convey information, support their statements with data, incorporate credible outside sources as needed, and properly cite information from outside sources.”5 When planning sessions for EBIO 3940, we redesigned our instruction to give students opportunities to participate in scholarly conversations so they can join the community of scientists.</p
Topical, geospatial, and temporal diffusion of the 2015 North American Menopause Society position statement on nonhormonal management of vasomotor symptoms
OBJECTIVE:
We sought to depict the topical, geospatial, and temporal diffusion of the 2015 North American Menopause Society position statement on the nonhormonal management of menopause-associated vasomotor symptoms released on September 21, 2015, and its associated press release from September 23, 2015.
METHODS:
Three data sources were used: online news articles, National Public Radio, and Twitter. For topical diffusion, we compared keywords and their frequencies among the position statement, press release, and online news articles. We also created a network figure depicting relationships across key content categories or nodes. For geospatial diffusion within the United States, we compared locations of the 109 National Public Radio (NPR) stations covering the statement to 775 NPR stations not covering the statement. For temporal diffusion, we normalized and segmented Twitter data into periods before and after the press release (September 12, 2015 to September 22, 2015 vs September 23, 2015 to October 3, 2015) and conducted a burst analysis to identify changes in tweets from before to after.
RESULTS:
Topical information diffused across sources was similar with the exception of the more scientific terms "vasomotor symptoms" or "vms" versus the more colloquial term "hot flashes." Online news articles indicated media coverage of the statement was mainly concentrated in the United States. NPR station data showed similar proportions of stations airing the story across the four census regions (Northeast, Midwest, south, west; P = 0.649). Release of the statement coincided with bursts in the menopause conversation on Twitter.
CONCLUSIONS:
The findings of this study may be useful for directing the development and dissemination of future North American Menopause Society position statements and/or press releases
Group-theoretical analysis of structural instability, vacancy ordering and magnetic transitions in the system troilite (FeS)-pyrrhotite (Fe<inf>1-x</inf>S)
© International Union of Crystallography 2019. A group-theoretical framework to describe vacancy ordering and magnetism in the Fe 1-x S system is developed. This framework is used to determine the sequence of crystal structures consistent with the observed magnetic structures of troilite (FeS), and to determine the crystallographic nature of the low-temperature Besnus transition in Fe 0.875 S. It is concluded that the Besnus transition is a magnetically driven transition characterized by the rotation of the moments out of the crystallographic plane to which they are confined above the transition, accompanied by small atomic displacements that lower the symmetry from monoclinic to triclinic at low temperatures. Based on the phase diagram, magnetically driven phase transitions at low temperatures are predicted in all the commensurate superstructures of pyrrhotite. Based on the phase diagram, magnetically driven spin reorientations at low temperatures are predicted in all the commensurate superstructures of pyrrhotite. The exact nature of the spin rotation is determined by the symmetry of the vacancy-ordered state and based on this spin-flop transitions in 3C and 5C pyrrhotite and a continuous rotation akin to that seen in 4C pyrrhotite are predicted. A Besnus-type transition is also possible in 6C pyrrhotite. Furthermore, it is clarified that 3C and 4C pyrrhotite carry a ferrimagnetic moment whereas 5C and 6C are antiferromagnetic
Norms of Punishment: Experiments with students and the General Population
Norms of cooperation and punishment differ across societies, but also within a single society. In an experiment with two subject pools sharing the same geographical and cultural origins, we show that opportunities for peer punishment increase cooperation among students but not in the general population. In previous studies, punishment magnified the differences across societies in people\u2019s ability to cooperate. Here, punishment reversed the order: with punishment, students cooperate more than the general population while they cooperate less without it
Integrin α6β4 Promotes Autocrine Epidermal Growth Factor Receptor (EGFR) Signaling to Stimulate Migration and Invasion toward Hepatocyte Growth Factor (HGF)
Integrin α6β4 is up-regulated in pancreatic adenocarcinomas where it contributes to carcinoma cell invasion by altering the transcriptome. In this study, we found that integrin α6β4 up-regulates several genes in the epidermal growth factor receptor (EGFR) pathway, including amphiregulin (AREG), epiregulin (EREG), and ectodomain cleavage protease MMP1, which is mediated by promoter demethylation and NFAT5. The correlation of these genes with integrin α6β4 was confirmed in The Cancer Genome Atlas Pancreatic Cancer Database. Based on previous observations that integrin α6β4 cooperates with c-Met in pancreatic cancers, we examined the impact of EGFR signaling on hepatocyte growth factor (HGF)-stimulated migration and invasion. We found that AREG and EREG were required for autocrine EGFR signaling, as knocking down either ligand inhibited HGF-mediated migration and invasion. We further determined that HGF induced secretion of AREG, which is dependent on integrin-growth factor signaling pathways, including MAPK, PI3K, and PKC. Moreover, matrix metalloproteinase activity and integrin α6β4 signaling were required for AREG secretion. Blocking EGFR signaling with EGFR-specific antibodies or an EGFR tyrosine kinase inhibitor hindered HGF-stimulated pancreatic carcinoma cell chemotaxis and invasive growth in three-dimensional culture. Finally, we found that EGFR was phosphorylated in response to HGF stimulation that is dependent on EGFR kinase activity; however, c-Met phosphorylation in response to HGF was unaffected by EGFR signaling. Taken together, these data illustrate that integrin α6β4 stimulates invasion by promoting autocrine EGFR signaling through transcriptional up-regulation of key EGFR family members and by facilitating HGF-stimulated EGFR ligand secretion. These signaling events, in turn, promote pancreatic carcinoma migration and invasion
Quantitative Assessment of the Risk of Release of Foot-and-Mouth Disease Virus via Export of Bull Semen from Israel
Various foot-and-mouth disease (FMD) virus strains circulate in the Middle East, causing frequent episodes of FMD outbreaks among Israeli livestock. Since the virus is highly resistant in semen, artificial insemination with contaminated bull semen may lead to the infection of the receiver cow. As a non-FMD-free country with vaccination, Israel is currently engaged in trading bull semen only with countries of the same status. The purpose of this study was to assess the risk of release of FMD virus through export of bull semen in order to estimate the risk for FMD-free countries considering purchasing Israeli bull semen. A stochastic risk assessment model was used to estimate this risk, defined as the annual likelihood of exporting at least one ejaculate of bull semen contaminated with viable FMD virus. A total of 45 scenarios were assessed to account for uncertainty and variability around specific parameter estimates and to evaluate the effect of various mitigation measures, such as performing a preexport test on semen ejaculates. Under the most plausible scenario, the annual likelihood of exporting bull semen contaminated with FMD virus had a median of 1.3 * 10(-7) for an export of 100 ejaculates per year. This corresponds to one infected ejaculate exported every 7 million years. Under the worst-case scenario, the median of the risk rose to 7.9 * 10(-5), which is equivalent to the export of one infected ejaculate every 12,000 years. Sensitivity analysis indicated that the most influential parameter is the probability of viral excretion in infected bulls
Theobald Palm and His Remarkable Observation: How the Sunshine Vitamin Came to Be Recognized
The seminal discovery that sunlight was important in the prevention of nutritional rickets was made in 1890 by Theobald A. Palm, a medical missionary who contrasted the prevalence of rickets in northern European urban areas with similar areas in Japan and other tropical countries. He surmised that exposure to sunlight prevented rickets. Over the next 40 years his observation led to an understanding of ultraviolet irradiation and its role in vitamin D synthesis. This opened a new era of appreciation for the curative powers of the sun and “the sunshine vitamin”. While Palm’s observations were in some ways obscure, they had a potent effect on the development of photobiology
The space density of cataclysmic variables: constraints from the ROSAT North Ecliptic Pole Survey
We use the ROSAT North Ecliptic Pole (NEP) survey to construct a small, but
purely X-ray flux-limited sample of cataclysmic variable stars (CVs). The
sample includes only 4 systems, 2 of which (RX J1715.6+6856 and RX
J1831.7+6511) are new discoveries. We present time-resolved spectroscopy of the
new CVs and measure orbital periods of 1.64 \pm 0.02 h and 4.01\pm 0.03 h for
RX 1715.6+6856 and RX J1831.7+6511, respectively. We also estimate distances
for all the CVs in our sample, based mainly on their apparent brightness in the
infrared. The space density of the CV population represented by our small
sample is (1.1 +2.3/-0.7) 10^-5 pc^-3. We can also place upper limits on the
space density of any sub-population of CVs too faint to be included in the NEP
survey. In particular, we show that if the overall space density of CVs is as
high as 2 10^-4 pc^-3 (as has been predicted theoretically), the vast majority
of CVs must be fainter than L_X \simeq 2 10^29 erg/s.Comment: 11 pages, 7 figure, accepted for publication in MNRA
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Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZrTiO (PZT)–PbFeTaO (PFT)
Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZrTiO–PbFeTaO (PZT–PFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZrTiO–PbFeNbO (PZT–PFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFeTaO. As for PZT–PFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubic–tetragonal–monoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a Vogel–Fulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZT–PFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales.RUS facilities in Cambridge were established with funding from the Natural Environment Research Council (Grants NE/B505738/1, NE/F017081/1). The present work was supported by Grant No. EP/ I036079/1 from the Engineering and Physical Sciences Research Council. We thank Dr. Sam Crossley for his assistance with dielectric analysis and the use of his software to run those measurements. JAS gratefully acknowledges the hospitality of the Max Planck Institute for Chemical Physics of Solids. The Nanopaleomagnetism lab has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007– 2013)/ERC Grant Agreement 320750. SED and HS acknowledge support from the Winton Programme for the physics of sustainability. HS also acknowledges support from the Funai Foundation for Information Technology and the British Council Japan Association. Part of the work was carried out at the University of Puerto Rico, supported by the DOEEBSCoR project DEG02-ER46526
Elastic and anelastic anomalies in (Ca,Sr)TiO3 perovskites: Analogue behaviour for silicate perovskites
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