Evaluation of MARC for the analysis of rotating composite blades

The suitability of the MARC code for the analysis of rotating composite blades was evaluated using a four-task process. A nonlinear displacement analysis and subsequent eigenvalue analysis were performed on a rotating spring mass system to ensure that displacement-dependent centrifugal forces were accounted for in the eigenvalue analysis. Normal modes analyses were conducted on isotropic plates with various degrees of twist to evaluate MARC's ability to handle blade twist. Normal modes analyses were conducted on flat composite plates to validate the newly developed coupled COBSTRAN-MARC methodology. Finally, normal modes analyses were conducted on four composite propfan blades that were designed, analyzed, and fabricated at NASA Lewis Research Center. Results were compared with experimental data. The research documented herein presents MARC as a viable tool for the analysis of rotating composite blades

Strength and duration of perisomatic GABAergic inhibition depend on distance between synaptically connected cells

GABAergic perisoma-inhibiting fast-spiking interneurons (PIIs) effectively control the activity of large neuron populations by their wide axonal arborizations. It is generally assumed that the output of one PII to its target cells is strong and rapid. Here, we show that, unexpectedly, both strength and time course of PII-mediated perisomatic inhibition change with distance between synaptically connected partners in the rodent hippocampus. Synaptic signals become weaker due to lower contact numbers and decay more slowly with distance, very likely resulting from changes in GABAA receptor subunit composition. When distance-dependent synaptic inhibition is introduced to a rhythmically active neuronal network model, randomly driven principal cell assemblies are strongly synchronized by the PIIs, leading to higher precision in principal cell spike times than in a network with uniform synaptic inhibition

Distance-dependent inhibition facilitates focality of gamma oscillations in the dentate gyrus

Gamma oscillations (30–150 Hz) in neuronal networks are associated with the processing and recall of information. We measured local field potentials in the dentate gyrus of freely moving mice and found that gamma activity occurs in bursts, which are highly heterogeneous in their spatial extensions, ranging from focal to global coherent events. Synaptic communication among perisomatic-inhibitory interneurons (PIIs) is thought to play an important role in the generation of hippocampal gamma patterns. However, how neuronal circuits can generate synchronous oscillations at different spatial scales is unknown. We analyzed paired recordings in dentate gyrus slices and show that synaptic signaling at interneuron-interneuron synapses is distance dependent. Synaptic strength declines whereas the duration of inhibitory signals increases with axonal distance among interconnected PIIs. Using neuronal network modeling, we show that distance-dependent inhibition generates multiple highly synchronous focal gamma bursts allowing the network to process complex inputs in parallel in flexibly organized neuronal centers

Stellar Double Coronagraph: a multistage coronagraphic platform at Palomar observatory

We present a new instrument, the "Stellar Double Coronagraph" (SDC), a flexible coronagraphic platform. Designed for Palomar Observatory's 200" Hale telescope, its two focal and pupil planes allow for a number of different observing configurations, including multiple vortex coronagraphs in series for improved contrast at small angles. We describe the motivation, design, observing modes, wavefront control approaches, data reduction pipeline, and early science results. We also discuss future directions for the instrument.Comment: 25 pages, 12 figures. Correspondence welcome. The published work is open access and differs trivially from the version posted here. The published version may be found at http://iopscience.iop.org/article/10.1088/1538-3873/128/965/075003/met

Fecal-Sac Ingestion by Spotted Towhees

Altricial nestlings encase excrement in fecal sacs that parents remove by either ingesting them or transporting them away from the nest. Ingestion may allow energetically or nutritionally deprived parents to recapture energy or nutrients that might be lost because of nestlings\u27 inefficient digestion (the parental-nutrition hypothesis ), but ingestion may also permit parents to avoid flights from the nest that interfere with parental care (e.g., brooding young; the economic-disposal hypothesis ). We used a hypothetico-deductive approach to test the two hypotheses\u27 ability to account for fecal-sac ingestion by the Spotted Towhee (Pipilo maculatus). We confirmed the parental-nutrition hypothesis\u27 predictions that more fecal sacs should be ingested in years of food shortage (males only), late in the season when food supplies decline (both sexes), by parents that had the greatest difficulty raising young (i.e., underweight young), and that adults\u27 body condition should vary directly with their rate of fecal-sac ingestion (females only). We rejected the economic-disposal hypothesis\u27 prediction of a decline in fecal-sac ingestion with increasing brood size. The latter, plus the observation that nearly 40% of males ingest fecal sacs despite their spending virtually no time attending nests, suggests that fecal-sac ingestion is not a mechanism to avoid needless and time-consuming flights from the nest that interfere with parental care. Fecal-sac ingestion by Spotted Towhees is better interpreted as either a resource supplement to parents or as a mechanism to satiate hunger so that parents can maintain rates of feeding to dependent young

Ovarian carcinosarcoma is a distinct form of ovarian cancer with poorer survival compared to tubo-ovarian high grade serous

BACKGROUND: Ovarian carcinosarcoma (OCS) is an uncommon, biphasic and highly aggressive ovarian cancer type, which has received relatively little research attention. METHODS: We curated the largest pathologically confirmed OCS cohort to date, performing detailed histopathological characterisation, analysis of features associated with survival and comparison against high-grade serous ovarian carcinoma (HGSOC). RESULTS: Eighty-two OCS patients were identified; overall survival was poor (median 12.7 months). In all, 79% demonstrated epithelial components of high-grade serous (HGS) type, while 21% were endometrioid. Heterologous elements were common (chondrosarcoma in 32%, rhabdomyosarcoma in 21%, liposarcoma in 2%); chondrosarcoma was more frequent in OCS with endometrioid carcinomatous components. Earlier stage, complete resection and platinum-containing adjuvant chemotherapy were associated with prolonged survival; however, risk of relapse and mortality was high across all patient groups. Histological subclassification did not identify subgroups with distinct survival. Compared to HGSOC, OCS patients were older (P < 0.0001), more likely to be FIGO stage I (P = 0.025), demonstrated lower chemotherapy response rate (P = 0.001) and had significantly poorer survival (P < 0.0001). CONCLUSION: OCS represents a distinct, highly lethal form of ovarian cancer for which new treatment strategies are urgently needed. Histological subclassification does not identify patient subgroups with distinct survival. Aggressive adjuvant chemotherapy should be considered for all cases, including those with early-stage disease

Improvement of the impact resistance of natural fiber–reinforced polypropylene composites through hybridization

Polypropylene (PP) hybrid composites were prepared by the combination of naturalreinforcements and poly(ethylene terephthalate) (PET) fibers. Wood, flax, and sugarpalm fibers were used to increase stiffness and strength, while PET fibers served toimprove impact resistance. Interfacial adhesion was increased by using a maleated PP(MAPP) coupling agent. The hybrid composites containing 20 wt% of the naturalfibers were homogenized in a twin-screw compounder and then injection moldedinto standard tensile specimens. The amount of PET fibers was changed from 0 to40 wt% in the composites. Tensile and impact testing, acoustic emission measure-ments, and scanning electron microscopy (SEM) were used for the characterizationof the composites as well as to follow deformation and failure processes. The resultsproved that the concept of using PET fibers to improve impact resistance works withall natural fibers. Local deformations, the debonding or pullout of the PET fibers, initi-ate the plastic deformation of the matrix, which consumes considerable energy. Thefracture of PET fibers might also contribute to energy absorption. The type of naturalfiber does not influence the effect; the amount of PET fibers determines fractureresistance. The improvement of interfacial adhesion by coupling increases strengthand slightly improves impact resistance. The overall properties of the hybrid compos-ites prepared are acceptable, sufficiently large stiffness and impact resistance beingachieved for a large number of structural application

The survival benefit associated with complete macroscopic resection in epithelial ovarian cancer is histotype-specific

Background: Complete macroscopic resection (CMR) is a key factor associated with prolonged survival in ovarian cancer. However, most evidence derives from high grade serous ovarian carcinoma (HGSOC), and the benefit of CMR in other histotypes is poorly characterised. We sought to determine which histotypes derive the greatest benefit from CMR to better inform future decisions on radical cytoreductive efforts. Methods: We performed multivariable analysis of disease-specific survival (DSS) across two independent patient cohorts to determine the magnitude of benefit associated with CMR within each histotype. Results: Across both cohorts (Scottish, n=1622; SEER, n=18947), CMR was associated with prolonged DSS; this was more marked in the Scottish cohort (multivariable HR 0.44, 95%CI 0.37-0.52 vs 0.59, 95%CI 0.57-0.62 in SEER). In both cohorts, clear cell ovarian carcinoma (CCOC) was among the histotypes to benefit most from CMR (multivariable HR 0.23 and 0.50 in Scottish and SEER cohorts); HGSOC cases demonstrated highly significant and clinically meaningful survival benefit, but this was of lower magnitude than in CCOC and endometrioid ovarian carcinoma (EnOC) across both cohorts. The benefit derived in low grade serous ovarian carcinoma is also high (multivariable HR 0.27 in Scottish cohort). CMR was associated with prolonged survival in mucinous ovarian carcinoma (MOC) patients in the SEER cohort (multivariable HR 0.65), but the associated failed to reach statistical significance in the Scottish cohort. Conclusions: The overall ovarian cancer patient population demonstrates significant survival benefit associated with CMR; however, the magnitude of benefit differs between histotypes. <br/