4,501 research outputs found

    Building on Community: A Community-Built Pipeline of Community College-Educated Secondary Mathematics Teachers of Color

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    The race/ethnic gap between secondary mathematics teachers and their students is widening as more students of color enroll in public schools. Community colleges serve local and diverse populations. Historical focus was on elementary education, but, nationally, community college students prepare for careers in secondary mathematics education. Despite Washington State’s strong community college network, few defined secondary mathematics teacher pathways exist. Washington State community colleges’ role in preparing secondary mathematics teachers of color is emerging but is not sufficient to overcome the secondary mathematics teacher shortage and race/ethnic gap. The purpose of this case study was to understand the role community colleges played in preparing current Washington State secondary mathematics teachers of color. Cases involved participants who earned community college credits prior to teaching certificate. Themes developed through teachers of color voice were evaluated through a Critical Race Theory lens to develop potential solutions to systems of oppression and build upon strengths. The role community colleges could play involves internal community college programming and external community engagement and outreach. Recommendations include 1) strengthening faculty advisors role, 2) incorporating cultural sensitivity training, 3) implementing a secondary mathematics teaching pathway, and 3) developing a future teacher group/club

    Relations of environmental contaminants, algal toxins, and diet with the reproductive success of American alligators on Florida Lakes

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    (113 page document

    Combined behavioral and neural investigations of pup retrieval

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    The ability to adequately adapt to a dramatically changing environment is crucial for an animal’s survival. When female mice give birth to their offspring, their environment changes drastically and they immediately need to care for the offspring, thereby ensuring the offspring’s wellbeing. Pups completely transform the environment around the mouse, triggering a number of new behaviors, as they provide a slew of new sensory inputs, including tactile and olfactory, but also auditory. Pups emit ultrasonic vocalizations (USVs) when isolated outside the nest, triggering retrieval behavior in mothers (MTs). After pups have returned to the nest and are cared for, the USV emission ceases. Interestingly, not only MTs but also virgin mice can perform pup retrieval, provided that they either have experience with pups in their home cage or are repeatedly exposed to pups in a pup retrieval task. Those two animal groups are referred to as experienced (EVs) and naive virgins (NVs). Studies have shown that excitatory neurons in the auditory cortex of MTs and EVs respond more strongly to pup calls over time. However, these studies have been performed under head-restrained unnatural conditions. Here, we provide a framework in which MTs, EVs and NVs retrieve pups in a semi-natural, freely behaving setting. During the experiment, they carry a head-mounted miniscope that allows for imaging neural activity in multiple neurons in the auditory cortex. The entire multisensory scenery is therefore accessible to mice, which was shown to impact auditory responses to pup calls. In our study, we show differences in behavioral performances of these three groups, with MTs displaying the most skilled and fine-tuned pup retrieval behavior, already highly effective during the final pregnancy stage. EVs show slightly reduced pup retrieval abilities, but superior to NVs, which retrieve pups effectively only after a few days. Additionally, we discovered that not only pups emitted USVs, but also adult mice vocalized. Intriguingly, they vocalized significantly more when pups were present in the behavioral arena, as compared to when they were alone. Clear pup call responsive neurons in the auditory cortex of all groups were scarce. Nevertheless, the overall neuronal population showed significant responses to pup calls at least in MTs, less so in EVs and least pronounced in NVs. Strikingly, other more global and behaviorally relevant events, such as pup retrievals and nest entries and exits, showed a distinct neural signature. Despite the scarcity of clear single cell responses to pup calls, the population of auditory cortex neurons carried information about pup call presence throughout all sessions in all groups, measured by a decoding analysis. This population code could be described as a sparse and dynamic code containing a few highly informative neurons, i.e. high weight neurons, that carried most of the decoding weight in a given session. This sparsity was most pronounced in MTs and least so in NVs. Besides, these high weight neurons were largely non-overlapping with high weight neurons for other non-pup call related event types. When relating single trial pup call decoding accuracies with the associated behavioral performance in a given trial, we could identify a significant relationship in EVs that was absent in MTs and NVs, suggesting that improved single trial decoding accuracies were linked to improved pup retrieval abilities. Altogether, this study shows how different pup exposure regimes can affect the learning of an essential offspring caring behavior and, that these different learning types differently enhance the neural representations of associated sensory cues

    Inter-institutional variations in oxytocin augmentation during labour in German university hospitals : a national survey

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    There are several international guidelines on oxytocin regimens for induction and augmentation of labour, but no agreement on a standardised regimen in Germany. This study collated and reviewed the oxytocin regimens used for labour augmentation in university hospitals, with the long-term aim of contributing to the development of a national clinical guideline

    Spin transport and spin dephasing in zinc oxide

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    The wide bandgap semiconductor ZnO is interesting for spintronic applications because of its small spin-orbit coupling implying a large spin coherence length. Utilizing vertical spin valve devices with ferromagnetic electrodes (TiN/Co/ZnO/Ni/Au), we study the spin-polarized transport across ZnO in all-electrical experiments. The measured magnetoresistance agrees well with the prediction of a two spin channel model with spin-dependent interface resistance. Fitting the data yields spin diffusion lengths of 10.8nm (2K), 10.7nm (10K), and 6.2nm (200K) in ZnO, corresponding to spin lifetimes of 2.6ns (2K), 2.0ns (10K), and 31ps (200K).Comment: 7 pages, 5 figures; supplemental material adde

    Correlation potentials for molecular bond dissociation within the self-consistent random phase approximation

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    Self-consistent correlation potentials for H2_2 and LiH for various inter-atomic separations are obtained within the random phase approximation (RPA) of density functional theory. The RPA correlation potential shows a peak at the bond midpoint, which is an exact feature of the true correlation potential, but lacks another exact feature: the step important to preserve integer charge on the atomic fragments in the dissociation limit. An analysis of the RPA energy functional in terms of fractional charge is given which confirms these observations. We find that the RPA misses the derivative discontinuity at odd integer particle numbers but explicitly eliminates the fractional spin error in the exact-exchange functional. The latter finding explains the accurate total energy in the dissociation limit.Comment: 9 pages, 10 figure

    Actividad física: algo más que gasto energético

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    Tradicionalmente, se ha considerado el balance energético como la diferencia entre consumo y gasto calórico, asociando resultados positivos a un incremento del índice de masa corporal, que puede conducir hacia sobrepeso u obesidad en casos extremos. En la actualidad, se conocen diversos factores genéticos, metabólicos y ambientales (regulación del apetito, intensidad del ejercicio, sedentarismo), que afectan al balance energético y están induciendo hacia una pandemia de enfermedades crónicas, como la obesidad. El avance del conocimiento científico viene indicando que el ejercicio físico planificado que cumpla con las recomendaciones de actividad física, hace aumentar el nivel de condición física, reduce el sedentarismo y provoca una disminución del índice de masa corporal con un descenso asociado del porcentaje de masa grasa, factores que inducen sobre el bienestar físico, psicológico y socio-emocional

    The timing of amniotomy, oxytocin and neuraxial analgesia and its association with labour duration and mode of birth

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    Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Purpose: The objective was to study the association of different timings of intrapartum interventions with labour duration and mode of birth. Methods: A longitudinal cohort study of 2,090 nulliparae and 1,873 multiparae with a singleton in cephalic presentation was conducted. We assessed the association between, on the one hand, the timing of augmentation with oxytocin, neuraxial analgesia and amniotomy, and, on the other hand, the time to complete dilatation, spontaneous or operative vaginal delivery or caesarean delivery, using a Cox regression model accounting for standard confounders. Results: From amniotomy onwards labour was accelerated. In multiparae, amniotomy was associated with an initial 6.6-fold acceleration, decreasing first stage duration until the hazard ratio reached around 3.5, where the intervention was performed 5 h after labour onset; thereafter, acceleration continued with a hazard ratio of around 3. In nulliparae, neuraxial analgesia was associated with a shorter first stage when administered between 7 and 11 h after labour onset; the later it was performed, the less likely was spontaneous birth and the more likely an operative vaginal birth in nulliparae or a caesarean section in multiparae. The start of oxytocin augmentation was associated with acceleration towards both full dilatation and caesarean section during first stage and an increased risk of operative vaginal birth during second stage. The later oxytocin augmentation started, the more likely it was that spontaneous birth would be retarded in multiparous women. Conclusions: Applying amniotomy, oxytocin and neuraxial analgesia at their optimal timing may improve the progress and outcome of labour

    Pregna-1,4,20-trien-3-one, a cytotoxic marine steroid from the marine soft coral Nephthea sp.

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    The title compound, C21H28O, was isolated from the cytotoxic lipid extract of the Fidjian soft coral Nephthea sp. The steroid showed inhibitory activity to human colon adenocarcinoma SW480 cells (IC50 = 2.5 µg ml−1). The mol­ecular structure indicates that the A ring is almost planar (r.m.s. deviation = 0.032 Å), the B and C rings adopt chair conformations and the five-membered D ring is a half-chair. The B/C and C/D ring junctions are trans-fused

    Enhancement of cargo processivity by cooperating molecular motors

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    Cellular cargo can be bound to cytoskeletal filaments by one or multiple active or passive molecular motors. Recent experiments have shown that the presence of auxiliary, nondriving motors, results in an enhanced processivity of the cargo, compared to the case of a single active motor alone. We model the observed cooperative transport process using a stochastic model that describes the dynamics of two molecular motors, an active one that moves cargo unidirectionally along a filament track and a passive one that acts as a tether. Analytical expressions obtained from our analysis are fit to experimental data to estimate the microscopic kinetic parameters of our model. Our analysis reveals two qualitatively distinct processivity-enhancing mechanisms: the passive tether can decrease the typical detachment rate of the active motor from the filament track or it can increase the corresponding reattachment rate. Our estimates unambiguously show that in the case of microtubular transport, a higher average run length arises mainly from the ability of the passive motor to keep the cargo close to the filament, enhancing the reattachment rate of an active kinesin motor that has recently detached. Instead, for myosin-driven transport along actin, the passive motor tightly tethers the cargo to the filament, suppressing the detachment rate of the active myosin.Comment: 11 pages, 8 figures, submitted to PCC
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