479 research outputs found

    Examining EC-6 Pre-Service Teachers\u27 Perceptions of Self-Efficacy in Teaching Mathematics

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    Mathematics teacher quality has become a major focus in national education reform efforts. In addition, there is an increasing interest in the effectiveness of teacher preparation programs and the undergraduate preparation of elementary mathematics teachers. Empirical evidence suggests that teacher attitudes, behaviors and values, or dispositions, towards teaching have a significant impact on student outcomes. The purpose of this study is to survey juniors and seniors in an undergraduate teacher preparation program to gauge their perceptions of self-efficacy and comfort with teaching mathematics. The results have implications for, and reaffirm concerns about the undergraduate preparation of elementary mathematics teachers

    The Anti-Apoptotic Effect of Respiratory Syncytial Virus on Human Peripheral Blood Neutrophils is Mediated by a Monocyte Derived Soluble Factor

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    Respiratory Syncytial Virus (RSV) causes annual epidemics of respiratory disease particularly affecting infants. The associated airway inflammation is characterized by an intense neutrophilia. This neutrophilic inflammation appears to be responsible for much of the pathology and symptoms. Previous work from our group had shown that there are factors within the airways of infants with RSV bronchiolitis that inhibit neutrophil apoptosis. This study was undertaken to determine if RSV can directly affect neutrophil survival

    Ataxia-telangiectasia-mutated (ATM) and NBS1-dependent phosphorylation of Chk1 on Ser-317 in response to ionizing radiation

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    In mammals, the ATM (ataxia-telangiectasia-mutated) and ATR (ATM and Rad3-related) protein kinases function as critical regulators of the cellular DNA damage response. The checkpoint functions of ATR and ATM are mediated, in part, by a pair of checkpoint effector kinases termed Chk1 and Chk2. In mammalian cells, evidence has been presented that Chk1 is devoted to the ATR signaling pathway and is modified by ATR in response to replication inhibition and UV-induced damage, whereas Chk2 functions primarily through ATM in response to ionizing radiation (IR), suggesting that Chk2 and Chk1 might have evolved to channel the DNA damage signal from ATM and ATR, respectively. We demonstrate here that the ATR-Chk1 and ATM-Chk2 pathways are not parallel branches of the DNA damage response pathway but instead show a high degree of cross-talk and connectivity. ATM does in fact signal to Chk1 in response to IR. Phosphorylation of Chk1 on Ser-317 in response to IR is ATM-dependent. We also show that functional NBS1 is required for phosphorylation of Chk1, indicating that NES1 might facilitate the access of Chk1 to ATM at the sites of DNA damage. Abrogation of Chk1 expression by RNA interference resulted in defects in IR-induced S and G2/M phase checkpoints; however, the overexpression of phosphorylation site mutant (S317A, S345A or S317A/S345A double mutant) Chk1 failed to interfere with these checkpoints. Surprisingly, the kinase-dead Chk1 (D130A) also failed to abrogate the S and G2 checkpoint through any obvious dominant negative effect toward endogenous Chk1. Therefore, further studies will be required to assess the contribution made by phosphorylation events to Chk1 regulation. Overall, the data presented in the study challenge the model in which Chk1 only functions downstream from ATR and indicate that ATM does signal to Chk1. In addition, this study also demonstrates that Chk1 is essential for IR-induced inhibition of DNA synthesis and the G2/M checkpoint

    Macrophages Are Required for Dendritic Cell Uptake of Respiratory Syncytial Virus from an Infected Epithelium

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    We have previously shown that the respiratory syncytial virus [RSV] can productively infect monocyte derived dendritic cells [MoDC] and remain dormant within the same cells for prolonged periods. It is therefore possible that infected dendritic cells act as a reservoir within the airways of individuals between annual epidemics. In the present study we explored the possibility that sub-epithelial DCs can be infected with RSV from differentiated bronchial epithelium and that in turn RSV from DCs can infect the epithelium. A dual co-culture model was established in which a differentiated primary airway epithelium on an Air Liquid Interface (ALI) was cultured on a transwell insert and MoDCs were subsequently added to the basolateral membrane of the insert. Further experiments were undertaken using a triple co-culture model in which in which macrophages were added to the apical surface of the differentiated epithelium. A modified RSV [rr-RSV] expressing a red fluorescent protein marker of replication was used to infect either the MoDCs or the differentiated epithelium and infection of the reciprocal cell type was assessed using confocal microscopy. Our data shows that primary epithelium became infected when rr-RSV infected MoDCs were introduced onto the basal surface of the transwell insert. MoDCs located beneath the epithelium did not become infected with virus from infected epithelial cells in the dual co-culture model. However when macrophages were present on the apical surface of the primary epithelium infection of the basal MoDCs occurred. Our data suggests that RSV infected dendritic cells readily transmit infection to epithelial cells even when they are located beneath the basal layer. However macrophages appear to be necessary for the transmission of infection from epithelial cells to basal dendritic cells

    TOI-3235 b: a transiting giant planet around an M4 dwarf star

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    We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry, and confirmed with radial velocities from ESPRESSO, and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of 0.665±0.025MJ\mathrm{0.665\pm0.025\,M_J} and a radius of 1.017±0.044RJ\mathrm{1.017\pm0.044\,R_J}. It orbits close to its host star, with an orbital period of 2.5926d\mathrm{2.5926\,d}, but has an equilibrium temperature of 604K\mathrm{\approx 604 \, K}, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of 0.3939±0.0030M\mathrm{0.3939\pm0.0030\,M_\odot}, a radius of 0.3697±0.0018R\mathrm{0.3697\pm0.0018\,R_\odot}, an effective temperature of 3389K\mathrm{3389 \, K}, and a J-band magnitude of 11.706±0.025\mathrm{11.706\pm0.025}. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M-dwarfs for atmospheric characterization.Comment: 15 pages, 4 figures. Accepted for publication in APJ

    Contrast sensitivity for motion detection and direction discrimination in adolescents with autism spectrum disorders and their siblings

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    The magnocellular (M) pathway hypothesis proposes that impaired visual motion perception observed in individuals with Autism Spectrum Disorders (ASD) might be mediated by atypical functioning of the subcortical M pathway, as this pathway provides the bulk of visual input to cortical motion detectors. To test this hypothesis, we measured luminance and chromatic contrast sensitivity, thought to tap M and Parvocellular (P) pathway processing, respectively. We also tested the hypothesis that motion processing is impaired in ASD using a novel paradigm that measures motion processing while controlling for detectabilty. Specifically, this paradigm compares contrast sensitivity for detection of a moving grating with contrast sensitivity for direction-of-motion discrimination of that same moving grating. Contrast sensitivities from adolescents with ASD were compared to typically-developing adolescents, and also unaffected siblings of individuals with ASD (SIBS). The results revealed significant group differences on P, but not M, pathway processing, with SIBS showing higher chromatic contrast sensitivity than both participants with ASD and TD participants. This atypicality, unique to SIBS, suggests the possible existence of a protective factor in these individuals against developing ASD. The results also revealed impairments in motion perception in both participants with ASD and SIBS, which may be an endophenotype of ASD. This impairment may be driven by impairments in motion detectors and/or by reduced input from neural areas that project to motion detectors, the latter possibility being consistent with the notion of reduced connectivity between neural areas in ASD

    Three long period transiting giant planets from TESS

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    We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single transit events in the light curves generated from the full frame images of the Transiting Exoplanet Survey Satellite (TESS). Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of MPM_P= 0.30 ±\pm 0.04 MJM_J , a radius of RPR_P= 1.00 ±\pm 0.02 RJR_J , and a low eccentricity orbit (e=0.15 ±\pm 0.05) with a period of P= 30.08364 ±\pm 0.00005 d . TOI 2338b has a mass of MPM_P= 5.98 ±\pm 0.20 MJM_J , a radius of RPR_P= 1.00 ±\pm 0.01 RJR_J , and a highly eccentric orbit (e= 0.676 ±\pm 0.002 ) with a period of P= 22.65398 ±\pm 0.00002 d . Finally, TOI 2589b has a mass of MPM_P= 3.50 ±\pm 0.10 MJM_J , a radius of RPR_P= 1.08 ±\pm 0.03 RJR_J , and an eccentric orbit (e = 0.522 ±\pm 0.006 ) with a period of P= 61.6277 ±\pm 0.0002 d . TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.Comment: 24 pages, 16 figures, accepted in A

    TOI-199 b: A well-characterized 100-day transiting warm giant planet with TTVs seen from Antarctica

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    We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5\,h long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199\,b has a 104.8540.002+0.001d\mathrm{104.854_{-0.002}^{+0.001} \, d} period, a mass of 0.17±0.02MJ\mathrm{0.17\pm0.02 \, M_J}, and a radius of 0.810±0.005RJ\mathrm{0.810\pm0.005 \, R_J}. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations, pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the non-transiting companion TOI-199 c, which has a period of 273.690.22+0.26d\mathrm{273.69_{-0.22}^{+0.26} \, d} and an estimated mass of 0.280.01+0.02MJ\mathrm{0.28_{-0.01}^{+0.02} \, M_J}. This period places it within the conservative Habitable Zone.Comment: 33 pages, 23 figures. Accepted for publication in A
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