Isotope tracing of nitrate : lessons from Malta

Average concentrations of nitrate in Malta’s groundwaters are probably the highest among EU member states. This compromises the quality of an important resource -almost 60% of Malta’s water supply being provided by groundwater. An 15N/14N + 18O/16O isotope study was undertaken as a core part of wide-ranging investigations into the potential sources of the nitrate pollution, its likely future trends, and possible ameliorative actions. The dual isotope (15N/14N + 18O/16O) approach was important for identifying waters affected by denitrification. Excluding these, groundwater from three physically and hydrologically distinct aquifers, with a very wide range in nitrate concentrations (24 to 410 mg NO3 L-1), had remarkably similar isotope compositions: 90% of samples lying within d15N ≈ +8 to +12‰, and d18O ≈ +3 to +6‰. The d18O values are entirely consistent with those expected for microbial nitrification in the presence of surface or groundwaters, and together with 15N values rule out nitrate derivation directly from fertilizers or sewage. In other studies the relatively high d15N values for the waters would probably have been interpreted as indicative of nitrate derived from manure. In Malta, however, cultivated soils have high d15N values, ≈ +6 to +11‰, very similar to the values for nitrate in the groundwater, and argue for a soil-derived source. The implications of a soil-source of such high nitrate levels are discussed, and the study emphasised the importance of characterising the compositions of soils in addition to other sources – a factor often neglected in isotope studies of nitrate

Building Middle-Level Mathematics Teachers\u27 Capacities as Teachers and Leaders: The Math in the Middle Institute Partnership

This article describes professional development for middle-level mathematics teachers offered through the Math in the Middle Institute Partnership, a National Science Foundation-funded project to build teachers’ capacities to improve mathematics learning for all students. An overview of the project, including descriptions of its goals and curriculum are provided. Detailed descriptions of two mathematics courses and one pedagogy course are offered. The mathematics courses included here are the introductory course to the Math in the Middle Institute, as well as one of the final math courses of the Institute in which participants apply mathematical knowledge and processes to real-world problems. The pedagogy course features curriculum that enables teachers to acquire an understanding of the nature and purpose of action research, and launches teachers into planning and implementing systematic inquiry in their own mathematics classrooms around topics of their choosing. The varied abilities of teachers, as well as growth in teachers’ mathematical and pedagogical capacities, are represented by several samples of student work provided within the article. In addition, mathematical and pedagogical products of student work are also provided through the project’s URL links. Improving teacher quality is identified as a national need in mathematics education and one many universities and schools across the country are working in partnership to try to address. This article describes a professional development project aimed at improving mathematics teaching and learning in the middle grades. An overview of the project, along with a close look at several of its course offerings, are presented highlighting mathematical and pedagogical goals, challenges, and accomplishments

Real-time testing of the on-site warning algorithm in southern California and its performance during the July 29 2008 M_w5.4 Chino Hills earthquake

The real-time performance of the τ_c -P_d on-site early warning algorithm currently is being tested within the California Integrated Seismic Network (CISN). Since January 2007, the algorithm has detected 58 local earthquakes in southern California and Baja with moment magnitudes of 3.0 ≤ M_w ≤ 5.4. Combined with newly derived station corrections the algorithm allowed for rapid determination of moment magnitudes and Modified Mercalli Intensity (MMI) with uncertainties of ±0.5 and ±0.7 units, respectively. The majority of reporting delays ranged from 9 to 16 s. The largest event, the July 29 2008 M_w5.4 Chino Hills earthquake, triggered a total of 60 CISN stations in epicentral distances of up to 250 km. Magnitude predictions at these stations ranged from M_w4.4 to M_w6.5 with a median of M_w5.6. The closest station would have provided up to 6 s warning at Los Angeles City Hall, located 50 km to the west-northwest of Chino Hills

Understanding Teacher Leadership in Middle School Mathematics: A Collaborative Research Effort

We report findings from a collaborative research effort designed to examine how teachers act as leaders in their schools. We find that teachers educated by the Math in the Middle Institute act as key sources of advice for colleagues within their schools while drawing support from a network consisting of other teachers in the program and university-level advisors. In addition to reporting on our findings, we reflect on our research process, noting some of the practical challenges involved, as well as some of the benefits of collaboration

The Remarkable Mid-Infrared Jet of Massive Young Stellar Object G35.20-0.74

The young massive stellar object G35.20-0.74 was observed in the mid-infrared using T-ReCS on Gemini South. Previous observations have shown that the near infrared emission has a fan-like morphology that is consistent with emission from the northern lobe of a bipolar radio jet known to be associated with this source. Mid-infrared observations presented in this paper show a monopolar jet-like morphology as well, and it is argued that the mid-infrared emission observed is dominated by thermal continuum emission from dust. The mid-infrared emission nearest the central stellar source is believed to be directly heated dust on the walls of the outflow cavity. The hydroxyl, water, and methanol masers associated with G35.20-0.74 are spatially located along these mid-infrared cavity walls. Narrow jet or outflow cavities such as this may also be the locations of the linear distribution of methanol masers that are found associated with massive young stellar objects. The fact that G35.20-0.74 has mid-infrared emission that is dominated by the outflow, rather than disk emission, is a caution to those that consider mid-infrared emission from young stellar objects as only coming from circumstellar disks.Comment: Accepted for publication in ApJ Letters; 4 pages; 2 figures; a version with full resolution images is available here: http://www.ctio.noao.edu/~debuizer

Profile, Plan and Section: Three Developments for Sea-Bed Survey

The purpose of this article is to offer a response to some of the requirements, indicated in previous contributions, in underwater measurement and detection. The instruments described here were demonstrated to delegates during the International Hydrographic Conference in April 1967. Most of the accompanying records were taken during the course of the Conference

Developing Effective Mathematics Teachers through National Science Foundation Funded Math and Science Partnership Grants

Every year the National Science Foundation (NSF) gathers together leadership teams of funded Math and Science Partnership programs (MSP) at a Learning Network Conference in Washington, D.C. The purpose of the annual conference is to bring together teams of MSP leaders who represent institution higher education (IHE) faculty from STEM disciplines, IHE education faculty, school partners, and project evaluators, to give them an opportunity to learn across projects, and provide opportunities for individual projects to reflect on their progress. For the last two years, 2011 and 2012, we were part of the conference’s organizing committee. During the two‐day conference, project teams were invited to articulate their theories of action for preparing teachers to be effective STEM teachers and to describe in broad strokes or in fine grain detail what was happening within their projects’ professional development opportunities. Projects also had the opportunity to share within a public forum the preliminary, incomplete, or final results emerging from projects’ evaluations or research efforts aiming to determine whether the MSP projects were deepening teachers’ content and pedagogical knowledge, changing teachers’ practices, and, ultimately, positively impacting students’ success