Interspecific competition underlying mutualistic networks

The architecture of bipartite networks linking two classes of constituents is affected by the interactions within each class. For the bipartite networks representing the mutualistic relationship between pollinating animals and plants, it has been known that their degree distributions are broad but often deviate from power-law form, more significantly for plants than animals. Here we consider a model for the evolution of the mutualistic networks and find that their topology is strongly dependent on the asymmetry and non-linearity of the preferential selection of mutualistic partners. Real-world mutualistic networks analyzed in the framework of the model show that a new animal species determines its partners not only by their attractiveness but also as a result of the competition with pre-existing animals, which leads to the stretched-exponential degree distributions of plant species.Comment: 5 pages, 3 figures, accepted version in PR

Characterizing Teaching Assistants’ Knowledge and Beliefs Following Professional Development Activities within an Inquiry-Based General Chemistry Context

The purpose of this investigation was to explore changes in undergraduate and graduate teaching assistants’ (TAs’) content knowledge and beliefs about teaching within the context of an inquiry-based laboratory course. TAs received professional development (PD), which was informed by the TA training literature base and was designed for TAs implementing a guided inquiry approach to general chemistry laboratory instruction. TAs engaged in ∼20 h of presemester PD and ∼30 h of weekly follow-up PD during the semester. The study utilized a multiple-methods approach within a social constructivist framework to assess changes in the TAs. Participants included eight graduate TAs and five undergraduate TAs. Data collection included TA pre-PD, post-PD, and semester-end surveys and two interviews of a subset of participants. The quantitative data were analyzed using descriptive and nonparametric statistics, and the qualitative data were analyzed using systematic data analysis. The results indicate that TAs’ content knowledge significantly improved following the PD (mean = 80.22, standard deviation = 11.80) (Z = −2.346, p = 0.019) and was maintained over the semester. Following PD, the TAs shifted their beliefs to be more aligned with inquiry-based instruction. The results of this investigation suggest that TA previous experience and teaching students in an inquiry-based lab may influence TAs’ beliefs. Future research will focus on examining the impact of TAs on student outcomes within a guided inquiry approach to general chemistry laboratory instruction

Investigating the role of a district science coordinator

This study explored the professional responsibilities of district science coordinators, their professional development (PD) experiences, the relationship between their role, responsibilities, district context, and background, and barriers encountered in their work. A national sample (n = 122) of self‐identified science coordinators completed a Science Coordinator Role Survey. Participants’ responses were analyzed using descriptive and correlational statistics. Following analysis of survey data, 16 participants (13.1%) were purposefully selected for semi‐structured follow‐up interviews. Results indicated the majority of respondents identified themselves as Caucasian, female, and had served in their position for less than 10 years. The typical science coordinator held a degree in a science content area and was a former science teacher. Respondents without science degrees tended to hold positions at small, remote, or rural school districts with responsibilities in multiple content areas. Participants also reported barriers of not having enough PD opportunities, lack of time, lack of emphasis on science instruction, and a lack of power to enforce policies within a district. Results characterize the professional responsibilities of coordinators, provide insight into the role of a science coordinator, and into how to create targeted PD for coordinators

Functionalization of Carbon Nanomaterial Surface by Doxorubicin and Antibodies to Tumor Markers

The actual task of oncology is effective treatment of cancer while causing a minimum harm to the patient. The appearance of polymer nanomaterials and technologies launched new applications and approaches of delivery and release of anticancer drugs. The goal of work was to test ultra dispersed diamonds (UDDs) and onion-like carbon (OLCs) as new vehicles for delivery of antitumor drug (doxorubicin (DOX)) and specific antibodies to tumor receptors. Stable compounds of UDDs and OLCs with DOX were obtained. As results of work, an effectiveness of functionalization was 2.94 % w/w for OLC-DOX and 2.98 % w/w for UDD-DOX. Also, there was demonstrated that UDD-DOX and OLC-DOX constructs had dose-dependent cytotoxic effect on tumor cells in the presence of trypsin. The survival of adenocarcinoma cells reduced from 52 to 28 % in case of incubation with the UDD-DOX in concentrations from 8.4–2.5 to 670–20 μg/ml and from 72 to 30 % after incubation with OLC-DOX. Simultaneously, antibodies to epidermal growth factor maintained 75 % of the functional activity and specificity after matrix-assisted pulsed laser evaporation deposition. Thus, the conclusion has been made about the prospects of selected new methods and approaches for creating an antitumor agent with capabilities targeted delivery of drugs

Laser treatment of Ag@ZnO nanorods as long-life-span SERS surfaces.

This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/am506622x.UV nanosecond laser pulses have been used to produce a unique surface nanostructuration of Ag@ZnO supported nanorods (NRs). The NRs were fabricated by plasma enhanced chemical vapor deposition (PECVD) at low temperature applying a silver layer as promoter. The irradiation of these structures with single nanosecond pulses of an ArF laser produces the melting and reshaping of the end of the NRs that aggregate in the form of bundles terminated by melted ZnO spherical particles. Well-defined silver nanoparticles (NPs), formed by phase separation at the surface of these melted ZnO particles, give rise to a broad plasmonic response consistent with their anisotropic shape. Surface enhanced Raman scattering (SERS) in the as-prepared Ag@ZnO NRs arrays was proved by using a Rhodamine 6G (Rh6G) chromophore as standard analyte. The surface modifications induced by laser treatment improve the stability of this system as SERS substrate while preserving its activity.We thank the Junta de Andalucía (TEP8067, FQM-6900 and P12-FQM-2265) and the Spanish Ministry of Economy and Competitiveness (Projects CONSOLIDER-CSD 2008-00023, MAT2011-28345-C02-02, MAT2013-40852-R, MAT2013-42900-P and RECUPERA 2020) for financial support. The authors also thank the European Union Seventh Framework Programme under Grant Agreements 312483-ESTEEM2 (Integrated Infrastructure Initiative-I3) and REGPOT-CT-2011-285895-Al-NANOFUNC, and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreement 291522 - 3DIMAGE. R. J. Peláez acknowledges the grant JCI-2012_13034 from the Juan de la Cierva program

Elementary science teachers’ integration of engineering design into science instruction: results from a randomised controlled trial

This randomised controlled trial used a mixed-methods approach to investigate the frequency and how elementary teachers integrated engineering design (ED) principles into their science instruction following professional development (PD). The ED components of the PD were aligned with Cunningham and Carlsen’s [(2014). Teaching engineering practices. Journal of Science Teacher Education, 25, 197–210] guidelines for ED PD and promoted inclusion of ED within science teaching. The treatment group included 219 teachers from 83 schools. Participants in the control group included 145 teachers from 60 schools in a mid-Atlantic state. Data sources, including lesson overviews and videotaped classroom observations, were analysed quantitatively to determine the frequency of ED integration and qualitatively to describe how teachers incorporated ED into instruction after attending the PD. Results indicated more participants who attended the PD (55%) incorporated ED into instruction compared with the control participants (24%), χ2(1, n = 401) = 33.225, p \u3c .001,  = 0.308. Treatment and control teachers taught similar science content (p’s \u3e .05) through ED lessons. In ED lessons, students typically conducted research and created and tested initial designs. The results suggest the PD supported teachers in implementing ED into their science instruction and support the efficacy of using Cunningham and Carlsen’s (2014) guidelines to inform ED PD design