The Relationship of Implicit Theories to Elementary Teachers’ Patterns of Engagement in a Mathematics-Focused Professional Development Setting

As elementary teachers aim to deepen their mathematical understandings, they engage in a relearning process that involves not only revisiting but also reconstructing their knowledge. To do so, meaningful engagement in immersion and practice-based experiences is required. This exploratory case study investigated the engagement patterns of two elementary teachers with varying implicit beliefs as they participated in a professional development that focused on relearning mathematics. Data were collected on the two participants in the form of video narratives, observation protocols, and interviews. Attention was given to their patterns of engagement in collaborative group settings as the participants moved through different phases of the professional development lesson. Results indicated that the engagement patterns of the two participants closely aligned with learning behaviors described in the implicit beliefs theory. In this way, the results suggested an extension of the implicit theories model to the relearning context. Additional implications and future questions are provided

Universality of electron accumulation at wurtzite c- and a-plane and zinc-blende InN surfaces

Electron accumulation is found to occur at the surface of wurtzite (112¯0), (0001), and (0001¯) and zinc-blende (001) InN using x-ray photoemission spectroscopy. The accumulation is shown to be a universal feature of InN surfaces. This is due to the low Г-point conduction band minimum lying significantly below the charge neutrality level

Investigation of the Ozone Formation Reaction Pathway: Comparisons of Full Configuration Interaction Quantum Monte Carlo and Fixed-Node Diffusion Monte Carlo with Contracted and Uncontracted MRCI

The association/dissociation reaction path for ozone (O2 + O ↔ O3) is notoriously difficult to describe accurately using ab initio electronic structure theory, due to the importance of both strong and dynamic electron correlations. Experimentally, spectroscopic studies of the highest lying recorded vibrational states combined with the observed negative temperature dependence of the kinetics of oxygen isotope exchange reactions confirm that the reaction is barrierless, consistent with the latest potential energy surfaces. Previously reported potentials based on Davidson-corrected internally contracted multireference configuration interaction (MRCI) suffer from a spurious reef feature in the entrance channel even when extrapolated towards the complete basis set limit. Here, we report an analysis of comparisons between a variety of electronic structure methods including internally contracted and uncontracted MRCI (with and without Davidson corrections), as well as full configuration interaction quantum Monte Carlo, fixed-node diffusion Monte Carlo, and density matrix renormalization group

Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation

Thecosome pteropods are abundant upper-ocean zooplankton that build aragonite shells. Ocean acidification results in the lowering of aragonite saturation levels in the surface layers, and several incubation studies have shown that rates of calcification in these organisms decrease as a result. This study provides a weight-specific net calcification rate function for thecosome pteropods that includes both rates of dissolution and calcification over a range of plausible future aragonite saturation states (Omega_Ar). We measured gross dissolution in the pteropod Limacina helicina antarctica in the Scotia Sea (Southern Ocean) by incubating living specimens across a range of aragonite saturation states for a maximum of 14 days. Specimens started dissolving almost immediately upon exposure to undersaturated conditions (Omega_Ar,0.8), losing 1.4% of shell mass per day. The observed rate of gross dissolution was different from that predicted by rate law kinetics of aragonite dissolution, in being higher at Var levels slightly above 1 and lower at Omega_Ar levels of between 1 and 0.8. This indicates that shell mass is affected by even transitional levels of saturation, but there is, nevertheless, some partial means of protection for shells when in undersaturated conditions. A function for gross dissolution against Var derived from the present observations was compared to a function for gross calcification derived by a different study, and showed that dissolution became the dominating process even at Omega_Ar levels close to 1, with net shell growth ceasing at an Omega_Ar of 1.03. Gross dissolution increasingly dominated net change in shell mass as saturation levels decreased below 1. As well as influencing their viability, such dissolution of pteropod shells in the surface layers will result in slower sinking velocities and decreased carbon and carbonate fluxes to the deep ocean

Resonances in a two-dimensional electron waveguide with a single delta-function scatterer

We study the conductance properties of a straight two-dimensional electron waveguide with an s-like scatterer modeled by a single delta-function potential with a finite number of modes. Even such a simple system exhibits interesting resonance phenomena. These resonances are explained in terms of quasi-bound states both by using a direct solution of the Schroedinger equation and by studying the Green's function of the system. Using the Green's function we calculate the survival probability as well as the power absorption and show the influence of the quasi-bound states on these two quantities.Comment: 5 pages, 6 figures, to be published in Physical Review

Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide

Southern Ocean pteropods at risk from ocean warming and acidification

Early life stages of marine calcifiers are particularly vulnerable to climate change. In the Southern Ocean aragonite undersaturation events and areas of rapid warming already occur and are predicted to increase in extent. Here, we present the first study to successfully hatch the polar pteropod Limacina helicina antarctica and observe the potential impact of exposure to increased temperature and aragonite undersaturation resulting from ocean acidification (OA) on the early life stage survival and shell morphology. High larval mortality (up to 39%) was observed in individuals exposed to perturbed conditions. Warming and OA induced extensive shell malformation and dissolution, respectively, increasing shell fragility. Furthermore, shell growth decreased, with variation between treatments and exposure time. Our results demonstrate that short-term exposure through passing through hotspots of OA and warming poses a serious threat to pteropod recruitment and long-term population viability

Tibouchina sellowiana (Cham.) Cogn,: rooting, anatomy and biochemical analyses in the four seasons

O presente trabalho buscou verificar os efeitos da aplica\ue7\ue3o de diferentes concentra\ue7\uf5es do \ue1cido indolbut\uedrico (AIB), em talco e em solu\ue7\ue3o, no enraizamento de estacas caulinares de Tibouchina sellowiana (Cham.) Cogn. coletadas nas quatro esta\ue7\uf5es do ano, bem como suas varia\ue7\uf5es anat\uf4micas e bioqu\uedmicas. Estacas semilenhosas foram tratadas com 0, 1500 e 3000 mg L-1 de \ue1cido indolbut\uedrico (AIB), em talco e solu\ue7\ue3o 50% alco\uf3lica. Ap\uf3s 65 dias em casa-de-vegeta\ue7\ue3o, foram avaliados a porcentagem de estacas enraizadas, o n\ufamero e o comprimento das ra\uedzes, a porcentagem de estacas com calos e a sobreviv\ueancia. O uso do AIB mostrou-se eficiente na indu\ue7\ue3o radicial, sendo indiferente a forma em que foi aplicado. As esta\ue7\uf5es mais promissoras foram a primavera (78,75%) com 3.000 mg L-1 ou mg kg-1 de AIB e o ver\ue3o (63,12%) com 1.500 mg L-1 ou mg kg-1 de AIB. Das sec\ue7\uf5es feitas na base das estacas, no momento da estaquia, n\ue3o foi detectada nenhuma poss\uedvel barreira anat\uf4mica ou diferen\ue7a estrutural que promovesse varia\ue7\uf5es no enraizamento. An\ue1lises bioqu\uedmicas feitas das estacas revelaram que as maiores concentra\ue7\uf5es de a\ue7\ufacares totais foram obtidas no inverno (83,21 mg g-1 de tecido) e no outono (72,79 mg g-1), as esta\ue7\uf5es que tamb\ue9m apresentaram as maiores concentra\ue7\uf5es de prote\uednas (4,69 e 3,95 mg g-1 respectivamente).The present work tried to verify the effects of application of different concentration of indolebutyric acid (IBA) in talc in solution, in the rooting of cutting of Tibouchina sellowiana (Cham.) Cogn. collected in the four seasons, as well as its anatomical and biochemical variation. The semiharwood cuttings were treated with 0, 1500 and 3000 mg L-1 indolebutyric acid (IBA), in powder and alchoolic solutions. After 65 days in a greenhouse, rooting percentage, length and number of roots, cutting with callus percentage and survival, were evaluated. The use of the IBA was efficient in the induction radicial, being indifferent the form in which it was applied. The most promising stations in the formation of the system radicial were the spring (78,75%) with 3000 mg L-1 or mg kg-1 IBA and the summer (63,12 %) with 1500 mg L-1 or mg kg-1 IBA. (82,50%) with 3000 mg kg-1 IBA. Considering the cutting in the base of the stakes, in the moment of the cutting, no possible anatomical barrier or structural difference were detected so that it should promoted variations in the answers of the rooting uring the four seasons. Biochemical analyses done from the cuttings collected in the four seasons revealed that the largest concentrations of total sugars were obtained in the winter (83,21 mg g-1) and in the autumn (72,79 mg g-1). The same stations also presented the largest protein concentrations (4,69 and 3,95 mg g-1 respectively)

Specific mesenchymal/epithelial induction of olfactory receptor, vomeronasal, and gonadotropin-releasing hormone (GnRH) neurons

We asked whether specific mesenchymal/epithelial (M/E) induction generates olfactory receptor neurons (ORNs), vomeronasal neurons (VRNs) and gonadotropin releasing hormone (GnRH) neurons—the major neuron classes associated with the olfactory epithelium (OE). To assess specificity of M/E-mediated neurogenesis, we compared the influence of frontonasal mesenchyme on frontonasal epithelium, which becomes the OE, with that of the forelimb bud. Despite differences in position, morphogenetic and cytogenic capacity, both mesenchymal tissues support neurogenesis, expression of several signaling molecules and neurogenic transcription factors in the frontonasal epithelium. Only frontonasal mesenchyme, however, supports OE-specific patterning and activity of a subset of signals and factors associated with OE differentiation. Moreover, only appropriate pairing of frontonasal epithelial and mesenchymal partners yields ORNs, VRNs, and GnRH neurons. Accordingly, the position and molecular identity of specialized frontonasal epithelia and mesenchyme early in gestation and subsequent inductive interactions, specifies the genesis and differentiation of peripheral chemosensory and neuroendocrine neurons