7,057 research outputs found
Imaging through turbulence with a quadrature-phase optical interferometer
We present an improved technique for imaging through turbulence at visible wavelengths using a rotation shearing pupil-plane interferometer, intended for astronomical and terrestrial imaging applications. While previous astronomical rotation shearing interferometers have made only visibility modulus measurements, this interferometer makes four simultaneous measurements on each interferometric baseline, with phase differences of π/2 between each measurement, allowing complex visibility measurements (modulus and phase) across the entire input pupil in a single exposure. This technique offers excellent wavefront resolution, allowing operation at visible wavelengths on large apertures, is potentially immune to amplitude fluctuations (scintillation), and may offer superior calibration capabilities to other imaging techniques. The interferometer has been tested in the laboratory under weakly aberrating conditions and at Palomar Observatory under ordinary astronomical observing conditions. This research is based partly on observations obtained at the Hale Telescope
Retrieval cues and syntactic ambiguity resolution:Speed-accuracy tradeoff evidence
Language comprehension involves coping with ambiguity and recovering from misanalysis. Syntactic ambiguity resolution is associated with increased reading times, a classic finding that has shaped theories of sentence processing. However, reaction times conflate the time it takes a process to complete with the quality of the behavior-related information available to the system. We therefore used the speed-accuracy tradeoff procedure (SAT) to derive orthogonal estimates of processing time and interpretation accuracy, and tested whether stronger retrieval cues (via semantic relatedness: neighed->horse vs. fell->horse) aid interpretation during recovery. On average, ambiguous sentences took 250ms longer (SAT rate) to interpret than unambiguous controls, demonstrating veridical differences in processing time. Retrieval cues more strongly related to the true subject always increased accuracy, regardless of ambiguity. These findings are consistent with a language processing architecture where cue-driven operations give rise to interpretation, and wherein diagnostic cues aid retrieval, regardless of parsing difficulty or structural uncertainty
The Coronal Abundance Anomalies of M Dwarfs
We analyze Chandra X-ray spectra of the M0 V+M0 V binary GJ 338. As
quantified by X-ray surface flux, these are the most inactive M dwarfs ever
observed with X-ray grating spectroscopy. We focus on measuring coronal
abundances, in particular searching for evidence of abundance anomalies related
to First Ionization Potential (FIP). In the solar corona and wind, low FIP
elements are overabundant, which is the so-called "FIP effect." For other
stars, particularly very active ones, an "inverse FIP effect" is often
observed, with low FIP elements being underabundant. For both members of the GJ
338 binary, we find evidence for a modest inverse FIP effect, consistent with
expectations from a previously reported correlation between spectral type and
FIP bias. This amounts to strong evidence that all M dwarfs should exhibit the
inverse FIP effect phenomenon, not just the active ones. We take the first step
towards modeling the inverse FIP phenomenon in M dwarfs, building on past work
that has demonstrated that MHD waves coursing through coronal loops can lead to
a ponderomotive force that fractionates elements in a manner consistent with
the FIP effect. We demonstrate that in certain circumstances this model can
also lead to an inverse FIP effect, pointing the way to more detailed modeling
of M dwarf coronal abundances in the future.Comment: to appear in The Astrophysical Journa
What's the best way to motivate patients to exercise?
There is no single best strategy to motivate patients to exercise, given the lack of data from rigorous comparison studies. There are, however, several interventions for adults that are effective. They include: writing a patient-specific behavioral health ���green� prescription, encouraging patients to join forces with accountability partners or support groups, recommending the use of pedometers (strength of recommendation [SOR]: A, meta-analyses). In children and adolescents, multi-component strategies that include school-based interventions combined with either family or community involvement increase physical activity (SOR: A, systematic review)
Secondary Students' Involvement in Their IEP Meetings: Administrators' Perceptions
Secondary administrators in one southwestern state answered a 10-question web-based survey about student preparation for and involvement in their IEP meetings. Almost half of the 456 building-level special education administrative contacts who received our e-mail request completed the survey. Administrators reported that their schools teach students about their disability, invite them to their IEP meetings, encourage their participation at IEP meetings, and solicit student opinions during the meetings. Few administrators expected students to lead their own IEP meeting. Responses differed by administrative role. Principals answered questions differently than special education directors and special education teachers working part-time as administrators. The administrators' perceptions of student involvement differed from the results of direct observations of secondary IEP meetings.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Partial protein sequence of mouse and bovine kidney angiotensin converting enzyme
Partial protein sequence of mouse and bovine kidney angiotensin converting enzyme. Angiotensin converting enzyme (ACE) plays an important role in the regulation of renal blood pressure by the hydrolysis of the inactive precursor peptide angiotensin I to the potent vasopressor angiotensin II. Renal ACE is a surface membrane protein of both endothelium and tubular epithelium. Enzymatically active ACE was isolated from renal homogenates by chromatography using an affinity column constructed by linking an ACE inhibitor, lisinopril, to Affi-Gel 15. Analysis of eluates from this column showed that ACE activity was increased greater than 500-fold. SDS-polyacrylamide gel electrophoresis demonstrated a single band of molecular weight 144 kD (mouse) and 149 kD (bovine). N-terminal amino acid sequence analysis revealed:1 10 20I I IMouse LDPGLQPGNESPDEAGAQLFBovine ELDPALQPGNFPADEAGAQIFAI I I1 10 20Though bovine ACE has one additional N-terminal amino acid, these two partial sequences are highly homologous (16 of 20 positions are identical). Mouse ACE was digested with trypsin and the peptides were isolated by reverse phase HPLC. Analysis of the amino acid sequences showed that these tryptic peptides were unique to ACE. Thus, we were able to isolate ACE from bovine and mouse kidneys and show that they had substantial structural homology. They were also quite similar to that from rabbit lung
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