Structural basis of a phototropin light switch

Phototropins are light-activated kinases important for plant responses to blue light. Light initiates signaling in these proteins by generating a covalent protein-flavin mononucleotide (FMN) adduct within sensory Per-ARNT-Sim (PAS) domains. We characterized the light-dependent changes of a phototropin PAS domain by solution nuclear magnetic resonance spectroscopy and found that an alpha helix located outside the canonical domain plays a key role in this activation process. Although this helix associates with the PAS core in the dark, photoinduced changes in the domain structure disrupt this interaction. We propose that this mechanism couples light-dependent bond formation to kinase activation and identifies a signaling pathway conserved among PAS domains.     

The technology path to deep greenhouse gas emissions cuts by 2050: the pivotal role of electricity

Several states and countries have adopted targets for deep reductions in greenhouse gas emissions by 2050, but there has been little physically realistic modeling of the energy and economic transformations required. We analyzed the infrastructure and technology path required to meet California's goal of an 80% reduction below 1990 levels, using detailed modeling of infrastructure stocks, resource constraints, and electricity system operability. We found that technically feasible levels of energy efficiency and decarbonized energy supply alone are not sufficient; widespread electrification of transportation and other sectors is required. Decarbonized electricity would become the dominant form of energy supply, posing challenges and opportunities for economic growth and climate policy. This transformation demands technologies that are not yet commercialized, as well as coordination of investment, technology development, and infrastructure deployment.     

Web-based technology: its effects on small group "problem-based learning" interactions in a professional veterinary medical program

The objective of this investigation was to ascertain whether and how the introduction of a new technology (WebCT) influenced faculty teaching styles while facilitating small group problem-based learning (PBL) sessions in a professional veterinary medical (PVM) program. The following questions guided the study: (1) How does the use of technology affect faculty teaching behaviors? (2) Do the facilitators' interactions with WebCT technology change over the course of one semester? (3) What is the perceived impact of WebCT on facilitators' role in PBL? The study employed a combination of qualitative (case study) and semi-quantitative (survey) methods to explore these issues. Nine clinical sciences faculty members, leading a total of six PBL groups, were observed over the course of an academic semester for a total of 20 instructional sessions. The qualitative data gathered by observing faculty as they facilitated PBL sessions yielded three major themes: (1) How do PBL facilitators adapt to the addition of WebCT technology? (2) Does this technology affect teaching? and (3) How do PBL facilitators interact with their students and each other over the course of a semester? No direct evidence was found to suggest that use of WebCT affected teaching behaviors (e.g., student-centered vs. teacher-centered instruction). However, all facilitators showed a moderate increase in comfort with the technology during the semester, and one participant showed remarkable gains in technology skills. The teaching theme provided insight into how facilitators foster learning in a PBL setting as compared to a traditional lecture. A high degree of variability in teaching styles was observed, but individuals' styles tended to remain stable over the course of the semester. Nevertheless, all facilitators interacted similarly with students, in a more caring and approachable manner, when compared to the classroom or clinic atmospheres.     

Measurement of corneal sensitivity in 20 ophthalmologically normal alpacas

Objective To determine corneal sensitivity in 20 healthy adult alpacas (40 eyes) in order to establish reference values. Design Prospective study. Animals Twenty healthy, adult alpacas. Procedures Corneal sensitivity was determined by the corneal touch threshold (CTT) using a Cochet‐Bonnet esthesiometer. Five different regions of the cornea were evaluated (nasal, ventral, lateral, dorsal, and central). Results Corneal touch threshold values (in mm filament length) obtained from five corneal regions demonstrated varying corneal sensitivities. The central region (34.5 ± 7.1 mm) was the most sensitive, followed by the ventral (29.5 ± 7.2 mm), medial (29.3 ± 7.3 mm), dorsal (25.6 ± 6.3 mm), and lateral (21.8 ± 5.7 mm) regions. All pairwise comparisons of regional differences were statistically significant (P < 0.05), except for the comparison between the ventral and medial regions (P = 0.88). Evaluation of the CCT while controlling for age (2–5 years vs. 6–10 years) demonstrated an increased CTT with an increasing age for the central, ventral, medial and lateral regions. A decrease in the CTT of the dorsal region was noted with increasing age. Conclusion and Clinical Relevance Corneal touch threshold values in 40 eyes of 20 healthy adult alpacas were determined using a Cochet‐Bonnet esthesiometer. This study demonstrated the central corneal region to be most sensitive. Values obtained may serve as reference values in subsequent studies.     

Accuracy of a rapid enzyme-linked immunosorbent assay to measure progesterone in mares

The aim of this study was to validate an enzyme-linked immunosorbent assay (ELISA) for the measurement of progesterone (P4) in mares. Specifically, the objectives were as follows: (1) to determine the specificity and sensitivity of the ELISA test for determination of P4, (2) to measure the potential agreement between the 2 people performing the test, and 3) to evaluate the effect of time on the outcome. Ten mares were sampled on the day before ovulation (D-1), and on days 1 (D1), 3 (D3), and 5 (D5) following ovulation, during the reproductive season. While mares were cycling regularly, estrus was induced by the injection of 5 mg of prostaglandin (PGF2) and monitored starting on the 4th day by daily transrectal palpation and ultrasonography to determine the time of ovulation. Blood was collected and all samples (n=96) were assayed for P4 by a semiquantitative ELISA, by chemiluminescent immunoassay, and by radioimmunoassay (RIA). Based on the RIA, values of P4 on D-1, D1, D3, and D5 were significantly different (P < 0.0001) with mean and standard deviation(s) of 0.004, s = 0.52; 2.05, s = 2.58; 8.37, s = 4.17; and 12.76, s = 4.00 ng/mL respectively. The sensitivity and specificity of the semiquantitative assay were 94% and 95%, respectively for the lowest values of P4 (< 1.0 ng/mL). The value of kappa was 0.90 between 2 individuals performing the test. In conclusion, these results suggest that the semiquantitative test may be used reliably and economically to evaluate P4 levels in equine plasma in the clinical     

Middle Stone Age bedding construction and settlement patterns at Sibudu, South Africa

The Middle Stone Age (MSA) is associated with early behavioral innovations, expansions of modern humans within and out of Africa, and occasional population bottlenecks. Several innovations in the MSA are seen in an archaeological sequence in the rock shelter Sibudu (South Africa). At ~77,000 years ago, people constructed plant bedding from sedges and other monocotyledons topped with aromatic leaves containing insecticidal and larvicidal chemicals. Beginning at ~73,000 years ago, bedding was burned, presumably for site maintenance. By ~58,000 years ago, bedding construction, burning, and other forms of site use and maintenance intensified, suggesting that settlement strategies changed. Behavioral differences between ~77,000 and 58,000 years ago may coincide with population fluctuations in Africa.     

Collaborative development of the Arrowsmith two node search interface designed for laboratory investigators

Arrowsmith is a unique computer-assisted strategy designed to assist investigators in detecting biologically-relevant connections between two disparate sets of articles in Medline. This paper describes how an inter-institutional consortium of neuroscientists used the UIC Arrowsmith web interface http://arrowsmith.psych.uic.edu in their daily work and guided the development, refinement and expansion of the system into a suite of tools intended for use by the wider scientific community.