3,179 research outputs found
Final STS-35 Columbia descent BET products and results for LaRC OEX investigations
Final STS-35 'Columbia' descent Best Estimate Trajectory (BET) products have been developed for Langley Research Center (LaRC) Orbiter Experiments (OEX) investigations. Included are the reconstructed inertial trajectory profile; the Extended BET, which combines the inertial data and, in this instance, the National Weather Service atmospheric information obtained via Johnson Space Center; and the Aerodynamic BET. The inertial BET utilized Inertial Measurement Unit 1 (IMU1) dynamic measurements for deterministic propagation during the ENTREE estimation process. The final estimate was based on the considerable ground based C-band tracking coverage available as well as Tracking Data and Relay Satellite System (TDRSS) Doppler data, a unique use of the latter for endo-atmospheric flight determinations. The actual estimate required simultaneous solutions for the spacecraft position and velocity, spacecraft attitude, and six IMU parameters - three gyro biases and three accelerometer scale factor correction terms. The anchor epoch for this analysis was 19,200 Greenwich Mean Time (GMT) seconds which corresponds to an initial Shuttle altitude of approximately 513 kft. The atmospheric data incorporated were evaluated based on Shuttle derived considerations as well as comparisons with other models. The AEROBET was developed based on the Extended BET, the measured spacecraft configuration information, final mass properties, and the final Orbiter preoperation databook. The latter was updated based on aerodynamic consensus incrementals derived by the latest published FAD. The rectified predictions were compared versus the flight computed values and the resultant differences were correlated versus ensemble results for twenty-two previous STS entry flights
Does a peer model's task proficiency influence children's solution choice and innovation?
This work was supported by a Durham Doctoral Fellowship to L.A.W.The current study investigated whether 4- to 6-year-old children's task solution choice was influenced by the past proficiency of familiar peer models and the children's personal prior task experience. Peer past proficiency was established through behavioral assessments of interactions with novel tasks alongside peer and teacher predictions of each child's proficiency. Based on these assessments, one peer model with high past proficiency and one age-, sex-, dominance-, and popularity-matched peer model with lower past proficiency were trained to remove a capsule using alternative solutions from a three-solution artificial fruit task. Video demonstrations of the models were shown to children after they had either a personal successful interaction or no interaction with the task. In general, there was not a strong bias toward the high past-proficiency model, perhaps due to a motivation to acquire multiple methods and the salience of other transmission biases. However, there was some evidence of a model-based past-proficiency bias; when the high past-proficiency peer matched the participants' original solution, there was increased use of that solution, whereas if the high past-proficiency peer demonstrated an alternative solution, there was increased use of the alternative social solution and novel solutions. Thus, model proficiency influenced innovation.PostprintPeer reviewe
Exploration of implementation variables impacting trauma informed practices in schools: A narrative review
Current literature suggests that by using trauma- informed practices (TIP) in our schools and classrooms, positive short and long-term outcomes can be achieved for both children and their communities. However, there is little research identifying what helps or hinders the implementation of trauma-informed practice in schools or the development of a practitioner’s trauma-informed pedagogy. As part of this narrative review, 25 trauma- informed practice implementation variables were identified from 34 peer-reviewed works of current (2015-2020) literature using a process of thematic analysis. This review utilised an ecological model as an overlay to present these variables in a useable format. The results of this research may be utilised to identify unaddressed implementation variables that support practice change and TIP in schools. The literature and this review support the idea that, if given the right input, conditions and setting events, an effective trauma-informed practice or pedagogy can be developed. Furthermore, by helping practitioners fill the gaps in their knowledge and assisting them to develop their trauma-informed pedagogy, they are able to create an environment where students who have experienced complex trauma may be healthy, safe, engaged, and supported
Exploration of implementation variables impacting trauma informed practices in schools: A narrative review
Current literature suggests that by using trauma- informed practices (TIP) in our schools and classrooms, positive short and long-term outcomes can be achieved for both children and their communities. However, there is little research identifying what helps or hinders the implementation of trauma-informed practice in schools or the development of a practitioner’s trauma-informed pedagogy. As part of this narrative review, 25 trauma- informed practice implementation variables were identified from 34 peer-reviewed works of current (2015-2020) literature using a process of thematic analysis. This review utilised an ecological model as an overlay to present these variables in a useable format. The results of this research may be utilised to identify unaddressed implementation variables that support practice change and TIP in schools. The literature and this review support the idea that, if given the right input, conditions and setting events, an effective trauma-informed practice or pedagogy can be developed. Furthermore, by helping practitioners fill the gaps in their knowledge and assisting them to develop their trauma-informed pedagogy, they are able to create an environment where students who have experienced complex trauma may be healthy, safe, engaged, and supported
A Fresh Catch of Massive Binaries in the Cygnus OB2 Association
Massive binary stars may constitute a substantial fraction of progenitors to
supernovae and gamma-ray bursts, and the distribution of their orbital
characteristics holds clues to the formation process of massive stars. As a
contribution to securing statistics on OB-type binaries, we report the
discovery and orbital parameters for five new systems as part of the Cygnus OB2
Radial Velocity Survey. Four of the new systems (MT070, MT174, MT267, and MT734
(a.k.a. VI Cygni #11) are single-lined spectroscopic binaries while one (MT103)
is a double-lined system (B1V+B2V). MT070 is noteworthy as the longest period
system yet measured in Cyg OB2, with P=6.2 yr. The other four systems have
periods ranging between 4 and 73 days. MT174 is noteworthy for having a
probable mass ratio q<0.1, making it a candidate progenitor to a low-mass X-ray
binary. These measurements bring the total number of massive binaries in Cyg
OB2 to 25, the most currently known in any single cluster or association.Comment: Accepted for publication in the Astrophysical Journa
“Model age-based” and “copy when uncertain” biases in children’s social learning of a novel task
This work was supported by a John Templeton Foundation grant (40128).Theoretical models of social learning predict that individuals can benefit from using strategies that specify when and whom to copy. Here the interaction of two social learning strategies, model age-based biased copying and copy when uncertain, was investigated. Uncertainty was created via a systematic manipulation of demonstration efficacy (completeness) and efficiency (causal relevance of some actions). The participants, 4- to 6-year-old children (N = 140), viewed both an adult model and a child model, each of whom used a different tool on a novel task. They did so in a complete condition, a near-complete condition, a partial demonstration condition, or a no-demonstration condition. Half of the demonstrations in each condition incorporated causally irrelevant actions by the models. Social transmission was assessed by first responses but also through children’s continued fidelity, the hallmark of social traditions. Results revealed a bias to copy the child model both on first response and in continued interactions. Demonstration efficacy and efficiency did not affect choice of model at first response but did influence solution exploration across trials, with demonstrations containing causally irrelevant actions decreasing exploration of alternative methods. These results imply that uncertain environments can result in canalized social learning from specific classes of model.Publisher PDFPeer reviewe
Multi-Level Risk and Protective Factors for Substance Use among Zambian Street Youth
Background: High rates of substance use have been reported among youth in Zambia. This is particularly concerning given that substance use is one of the biggest risk factors placing young people at risk for HIV infection. Objectives: The purpose of the current study is to examine how multilevel risk and protective factors (i.e., community, family, peers, individual) influence alcohol and marijuana use. Methods: A total of 250 street youth in Lusaka, Zambia, were interviewed in the summer of 2014 about their alcohol and marijuana use and reasons for usage. Data were analyzed using descriptive and multivariate methods. Results: Youth reported high rates of alcohol use. At the multivariate level, peer- and individual-level variables (e.g., using alcohol or drugs for coping or for fun) explained the most variance, followed by family-level factors. Community-level variables explained the least variance in all models. Conclusion/Importance: A better understanding of multilevel risk and protective factors for young people’s alcohol and marijuana use could lead to the development of better intervention strategies to reduce this behavior among Zambian street youth
Improving the LSST dithering pattern and cadence for dark energy studies
The Large Synoptic Survey Telescope (LSST) will explore the entire southern
sky over 10 years starting in 2022 with unprecedented depth and time sampling
in six filters, . Artificial power on the scale of the 3.5 deg LSST
field-of-view will contaminate measurements of baryonic acoustic oscillations
(BAO), which fall at the same angular scale at redshift . Using the
HEALPix framework, we demonstrate the impact of an "un-dithered" survey, in
which of each LSST field-of-view is overlapped by neighboring
observations, generating a honeycomb pattern of strongly varying survey depth
and significant artificial power on BAO angular scales. We find that adopting
large dithers (i.e., telescope pointing offsets) of amplitude close to the LSST
field-of-view radius reduces artificial structure in the galaxy distribution by
a factor of 10. We propose an observing strategy utilizing large dithers
within the main survey and minimal dithers for the LSST Deep Drilling Fields.
We show that applying various magnitude cutoffs can further increase survey
uniformity. We find that a magnitude cut of removes significant
spurious power from the angular power spectrum with a minimal reduction in the
total number of observed galaxies over the ten-year LSST run. We also determine
the effectiveness of the observing strategy for Type Ia SNe and predict that
the main survey will contribute 100,000 Type Ia SNe. We propose a
concentrated survey where LSST observes one-third of its main survey area each
year, increasing the number of main survey Type Ia SNe by a factor of
1.5, while still enabling the successful pursuit of other science
drivers.Comment: 9 pages, 6 figures, published in SPIE proceedings; corrected typo in
equation
Conflicting evidence for the role of JNK as a target in breast cancer cell proliferation: comparisons between pharmacological inhibition and selective shRNA knockdown approaches
As a target, the JNK pathway has been implicated in roles including cell death, proliferation, and inflammation in variety of contexts which span cardiovascular disease, neurodegenerative pathologies, and cancer. JNK1 and JNK2 have recently been demonstrated to function independently, highlighting a new parameter in the study of the JNK pathway. In order for JNK1 and JNK2-specific roles to be defined, better tools need to be employed. Previous studies have relied upon the broad spectrum JNK inhibitor, SP600125, to characterize the role of JNK signaling in a number of cell lines, including the breast cancer cell line MCF-7. In line with previous literature, our study has demonstrated that SP600125 treatment inhibited c-Jun and JNK phosphorylation and MCF-7 proliferation. However, in addition to targeting JNK1, JNK2, and JNK3, SP600125 has been previously demonstrated to suppress the activity of a number of other serine/threonine kinases, making SP600125 an inadequate tool for JNK isoform-specific roles to be determined. In this study, lentiviral shRNA was employed to selectively knockdown JNK1, JNK2, and JNK1/2 in MCF-7 cells. Using this approach, JNK phosphorylation was fully inhibited following stable knockdown of respective JNK isoforms. Interestingly, despite suppression of JNK phosphorylation, MCF-7 cell proliferation, cell cycle progression, or cell death remained unaffected. These findings raise the question of whether JNK phosphorylation really is pivotal in MCF-7 cell growth and death or if suppression of these events is a result of one of the many off-targets cited for SP600125
- …