The GSFC Mark-2 three band hand-held radiometer

A self-contained, portable, hand-radiometer designed for field usage was constructed and tested. The device, consisting of a hand-held probe containing three sensors and a strap supported electronic module, weighs 4 1/2 kilograms. It is powered by flashlight and transistor radio batteries, utilizes two silicon and one lead sulfide detectors, has three liquid crystal displays, sample and hold radiometric sampling, and its spectral configuration corresponds to LANDSAT-D's thematic mapper bands. The device was designed to support thematic mapper ground-truth data collection efforts and to facilitate 'in situ' ground-based remote sensing studies of natural materials. Prototype instruments were extensively tested under laboratory and field conditions with excellent results

The metabolic syndrome adds utility to the prediction of mortality over its components: The Vietnam Experience Study

Background\ud The metabolic syndrome increases mortality risk. However, as “non-affected” individuals may still have up to two risk factors, the utility of using three or more components to identify the syndrome, and its predictive advantage over individual components have yet to be determined.\ud \ud Methods\ud Participants, male Vietnam-era veterans (n = 4265) from the USA, were followed-up from 1985/1986 for 14.7 years (61,498 person-years), and all-cause and cardiovascular disease deaths collated. Cox's proportional-hazards regression was used to assess the effect of the metabolic syndrome and its components on mortality adjusting for a wide range of potential confounders.\ud \ud Results\ud At baseline, 752 participants (17.9%) were identified as having metabolic syndrome. There were 231 (5.5%) deaths from all-causes, with 60 from cardiovascular disease. After adjustment for a range of covariates, the metabolic syndrome increased the risk of all-cause, HR 2.03, 95%CI 1.52, 2.71, and cardiovascular disease mortality, HR 1.92, 95%CI 1.10, 3.36. Risk increased dose-dependently with increasing numbers of components. The increased risk from possessing only one or two components was not statistically significant. The adjusted risk for four or more components was greater than for only three components for both all-cause, HR 2.30, 95%CI 1.45, 3.66 vs. HR 1.70, 95%CI 1.11, 2.61, and cardiovascular disease mortality, HR 3.34, 95%CI 1.19, 9.37 vs. HR 2.81, 95%CI 1.07, 7.35. The syndrome was more informative than the individual components for all-cause mortality, but could not be assessed for cardiovascular disease mortality due to multicollinearity. Hyperglycaemia was the individual strongest parameter associated with mortality.\ud \u

Ultrafast depolarization of the fluorescence in a conjugated polymer

The effect of the extent of pi electron conjugation on the primary photophysics in semiconducting polymers is reported. A rapid depolarization of photoluminescence and transient absorption, which indicates a reorientation of the transition dipole moment by similar to 30 degrees on a sub-100 fs time scale, is observed in the fully conjugated polymer poly[2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] (MEH-PPV). In contrast, partially conjugated polymers exhibit a much slower depolarization. The results reveal rapid changes of exciton delocalization in the fully conjugated MEH-PPV driven by structural relaxation

Gut microbiota-derived propionate reduces cancer cell proliferation in the liver

Peer reviewedPublisher PD

Bias in peer recognition does not explain differences in how men and women perceive their recognition in undergraduate physics courses

Gaining recognition as a physics person from peers is an important contributor to undergraduate students' persistence in physics courses and intentions to pursue a physics career. Previous research has separately demonstrated that women perceive less peer recognition than men (perceived recognition) in their physics courses and that women receive fewer nominations from their peers as strong in their physics course than men (received recognition). The relationship between perceived and received peer recognition, however, is not well understood. We conduct a large-scale, quantitative study of over 1,600 students enrolled in introductory physics courses at eight different institutions, including one Historically Black College or University and one Hispanic-Serving Institution. We use sophisticated statistical methods to directly compare student gender, perceived recognition, and received recognition, controlling for other student demographics and course-level variability. Results show with high precision that, for students receiving the same amount of recognition, and having the same race or ethnicity, academic year, and major, women report significantly lower perceived recognition than men. This study provides direct evidence that instructional interventions should target perceived recognition, rather than the ways in which students recognize their peers, such that all students appropriately internalize their peer recognition

Women perceive less peer recognition than men controlling for actual peer recognition

Gaining recognition from peers is important for students’ development of physics identity – the extent to which they view themselves as a physics person (Carlone & Johnson, 2007; Hazari, Sonnert, Sadler, & Shanahan, 2010). Previous research, however, has found gender differences in both perceived and actual recognition: men perceive significantly more recognition from others (perceived recognition) than women (Hazari, Sadler, & Sonnert, 2013) and men receive significantly more nominations for being strong in their physics course from peers (actual recognition) than women (Bloodhart, Balgopal, Casper, Sample McMeeking, & Fischer, 2020). These findings suggest a few possible relationships between gender, perceived recognition, and actual recognition, each of which suggests different implications. For example, it could be that men perceive more recognition than women on aggregate because men and women have similar perceived recognition from peers at every level of actual recognition, but men receive more actual recognition than women. Such a relationship would imply that instructors must create more gender equity in actual recognition, for instance by providing more ways for women to gain recognition from peers. Alternatively, men might perceive more recognition than women at every level of actual recognition. This relationship would imply that either men over-estimate their actual recognition or women under-estimate their actual recognition, or a combination of the two. The instructional implication in this case would be to ensure that all students appropriately perceive recognition from peers. We designed a study to determine these relationships using survey responses from students in introductory physics courses. We performed multiple different regression analyses relating gender, actual recognition from peers, and perceived recognition from peers. The best model revealed that controlling for actual recognition, women perceive significantly lower recognition from their peers than men (the second hypothesis above). These findings suggest that in order to decrease the gender difference in perceived peer recognition, and subsequently in physics identity, it is not sufficient to increase women’s actual recognition from peers. Instead, instructors must teach all students to appropriately acknowledge and internalize different forms of peer recognition in their physics courses, for example by teaching about intellectual humility (Sundstrom & Cardetti, 2021). REFERENCES Bloodhart, B., Balgopal, M. M., Casper, A. M. A., Sample McMeeking, L. B., & Fischer, E. V. (2020). Outperforming yet undervalued: Undergraduate women in STEM. PLoS One, 15(6), e0234685. Carlone, H. B., & Johnson, A. (2007). Understanding the science experiences of successful women of color: Science identity as an analytic lens. Journal of Research in Science Teaching, 44(8), 1187-1218. Hazari, Z., Sadler, P. M., & Sonnert, G. (2013). The science identity of college students: Exploring the intersection of gender, race, and ethnicity. Journal of College Science Teaching, 42(5), 82-91. Hazari, Z., Sonnert, G., Sadler, P. M., & Shanahan, M. C. (2010). Connecting high school physics experiences, outcome expectations, physics identity, and physics career choice: A gender study. Journal of Research in Science Teaching, 47(8), 978-1003. Sundstrom, M., & Cardetti, F. (2021). Exploring the introductory physics classroom through the lens of intellectual humility: Handling what you do not know. Physical Review Physics Education Research, 17(2), 020135

Ambulatory heart rate is underestimated when measured by an ambulatory blood pressure device

Objective: To test the validity of ambulatory heart rate (HR) assessment with a cuff ambulatory blood pressure (ABP) monitor. Design: Cross-instrument comparison of HR measured intermittently by a cuff ABP monitor (SpaceLabs, Redmond, Washington, USA), with HR derived from continuous electrocardiogram (ECG) recordings (1) in a controlled laboratory experiment and (2) during long-term recording in a true naturalistic setting. Participants: Six normotensive subjects participated in the laboratory study. A total of 109 male white-collar workers underwent ambulatory monitoring, of which 30 were mildly hypertensive. Methods: Four different laboratory conditions (postures: lying, sitting, standing, walking), repeated twice, were used to assess the short-term effects of cuff inflation on the HR. To test the actual ambulatory validity, participants simultaneously wore a continuous HR recorder and the ABP monitor from early morning to late evening on 2 workdays and one non-workday. Diary and vertical accelerometery information was used to obtain periods of fixed posture and (physical) activity across which HR from both devices was compared. Results: Laboratory results showed that the ABP device reliably detected HR during blood pressure measurement, but that this HR was systematically lower than the HR directly before and after the blood pressure measurement. The ambulatory study confirmed this systematic underestimation of the ongoing HR, but additionally showed that its amount increased when subjects went from sitting to standing to light physical activity (2.9; 4.3 and 9.1 bpm (beats/min), respectively). In spite of this activity-dependent underestimation of HR, the correlation of continuous ECG and intermittent ABP-derived HR was high (median r = 0.81). Also, underestimation was not different for normotensives and mild hypertensives. Conclusions: A direct effect of cuff inflation leads to the underestimation of ongoing HR during cuff-based ABP measurement. Additional underestimation of HR occurs during periods with physical activity, probably due to behavioural freezing during blood pressure measurements. HR underestimation was not affected by hypertensive state. When its limitations are taken into account, ABP-derived ambulatory HR can be considered a reliable and valid measure. © 2001 Lippincott Williams & Wilkins

The Global Ant Genomics Alliance (GAGA)

Peer reviewe

Placental syncytiotrophoblast constitutes a major barrier to vertical transmission of Listeria monocytogenes.

Listeria monocytogenes is an important cause of maternal-fetal infections and serves as a model organism to study these important but poorly understood events. L. monocytogenes can infect non-phagocytic cells by two means: direct invasion and cell-to-cell spread. The relative contribution of each method to placental infection is controversial, as is the anatomical site of invasion. Here, we report for the first time the use of first trimester placental organ cultures to quantitatively analyze L. monocytogenes infection of the human placenta. Contrary to previous reports, we found that the syncytiotrophoblast, which constitutes most of the placental surface and is bathed in maternal blood, was highly resistant to L. monocytogenes infection by either internalin-mediated invasion or cell-to-cell spread. Instead, extravillous cytotrophoblasts-which anchor the placenta in the decidua (uterine lining) and abundantly express E-cadherin-served as the primary portal of entry for L. monocytogenes from both extracellular and intracellular compartments. Subsequent bacterial dissemination to the villous stroma, where fetal capillaries are found, was hampered by further cellular and histological barriers. Our study suggests the placenta has evolved multiple mechanisms to resist pathogen infection, especially from maternal blood. These findings provide a novel explanation why almost all placental pathogens have intracellular life cycles: they may need maternal cells to reach the decidua and infect the placenta