An ion-exchange technique for concentrating ammonia from small volumes of seawater

An ion-exchange technique was used to concentrate ammonia from seawater. Precipitation of bivalent cations, prior to concentration, reduced the variability of ammonia recovery from the ion-exchange column and lengthened column life. Analysis of the eluate was by the phenolhypochlorite reaction. The method was designed for use with small seawater samples (>10ml) and has the advantage that it can be adapted for use with small volumes of seawater with no loss in sensitivity. In a 10 ml seawater example NH₃-N concentrations of 10–150 μg l^?1 were accurately determined.     

Triggering of El Niño by westerly wind events in a coupled general circulation model

Two ten-members ensemble experiments using a coupled ocean-atmosphere general circulation model are performed to study the dynamical response to a strong westerly wind event (WWE) when the tropical Pacific has initial conditions favourable to the development of a warm event. In the reference ensemble (CREF), no wind perturbation is introduced, whereas a strong westerly wind event anomaly is introduced in boreal winter over the western Pacific in the perturbed ensemble (CWWE). Our results demonstrate that an intense WWE is capable of establishing the conditions under which a strong El Niño event can occur. First, it generates a strong downwelling Kelvin wave that generates a positive sea surface temperature (SST) anomaly in the central-eastern Pacific amplified through a coupled ocean-atmosphere interaction. This anomaly can be as large as 2.5°C 60 days after the WWE. Secondly, this WWE also initiates an eastward displacement of the warm-pool that promotes the occurrence of subsequent WWEs in the following months. These events reinforce the initial warming through the generation of additional Kelvin waves and generate intense surface jets at the eastern edge of the warm-pool that act to further shift warm waters eastward. The use of a ten-members ensemble however reveals substantial differences in the coupled response to a WWE. Whereas four members of CWWE ensemble develop into intense El Niño warming as described above, four others display a moderate warming and two remains in neutral conditions. This diversity between the members appears to be due to the internal atmospheric variability during and following the inserted WWE. In the four moderate warm cases, the warm-pool is initially shifted eastward following the inserted WWE, but the subsequent weak WWE activity (when compared to the strong warming cases) prevents to further shift the warm-pool eastwards. The seasonal strengthening of trade winds in June–July can therefore act to shift warm waters back into the western Pacific, reducing the central-eastern Pacific warming. This strong sensitivity of the coupled response to WWEs may therefore limit the predictability of El Niño events, as the high frequency wind variability over the warm pool region remains largely unpredictable even at short time lead.     

The relationship between star formation rate and radio synchrotron luminosity at 0 < z < 2

We probe the relationship between star formation rate (SFR) and radio synchrotron luminosity in galaxies at  0 < z < 2  within the northern Spitzer Wide-area Infrared Extragalactic survey (SWIRE) fields, in order to investigate some of the assumptions that go into calculating the star formation history of the Universe from deep radio observations. We present new 610-MHz Giant Metrewave Radio Telescope (GMRT) observations of the European Large-Area ISO Survey-North 2 (ELAIS-N2) field, and using this data, along with previous GMRT surveys carried out in the ELAIS-N1 (North 1) and Lockman Hole regions, we construct a sample of galaxies which have redshift and SFR information available from the SWIRE survey. We test whether the local relationship between SFR and radio luminosity is applicable to   z = 2  galaxies, and look for evolution in this relationship with both redshift and SFR in order to examine whether the physical processes which lead to synchrotron radiation have remained the same since the peak of star formation in the Universe. We find that the local calibration between radio luminosity and star formation can be successfully applied to radio-selected high-redshift, high-SFR galaxies, although we identify a small number of sources where this may not be the case; these sources show evidence for inaccurate estimations of their SFR, but there may also be some contribution from physical effects such as the recent onset of starburst activity, or suppression of the radio luminosity within these galaxies.     

Local responses to changed circumstances: Coalmining in the market economy in Upper Silesia, Poland

It is argued that the emphasis of much recent research into coalmining has been placed on international and national scale influences which affect coalfields as a whole; change at the intra-coalfield scale has received less attention. After providing a background to events in Poland during communism, attention focuses on developments since 1989, commencing with coalfield-wide influences. There follows an examination of the work of the state body Państwowa Agencja Węgla Kamiennego, which executes government policy at the local level, and whose membership is drawn from the coalfield region. This agency recommends the closure and amalgamation of mines, but otherwise rationalisation measures are left to the seven mining companies and the colliery managers. The restructuring which has been carried out is considered under five heads: organisational change within the collieries, employment, production and technical change, and ecological adjustment. While recognising the importance of the socioeconomic and political environment and geology, there is much evidence to suggest that intra-coalfield patterns are strongly determined by local decision-makers. This revised version was published online in July 2006 with corrections to the Cover Date.     

Experimental study of dense pyroclastic density currents using sustained,gas-fluidized granular flows

Submarine lava flow morphology is commonly used to estimate relative flow velocity, but the effects of crystallinity and viscosity are rarely considered. We use digital petrography and quantitative textural analysis techniques to determine the crystallinity of submarine basaltic lava flows, using a set of samples from previously mapped lava flow fields at the hotspot-affected Galápagos Spreading Center. Crystallinity measurements were incorporated into predictive models of suspension rheology to characterize lava flow consistency and rheology. Petrologic data were integrated to estimate bulk lava viscosity. We compared the crystallinity and viscosity of each sample with its flow morphology to determine their respective roles in submarine lava emplacement dynamics. We find no correlation between crystallinity, bulk viscosity, and lava morphology, implying that flow advance rate is the primary control on submarine lava morphology. However, we show systematic variations in crystal size and shape distribution among pillows, lobates, and sheets, suggesting that these parameters are important indicators of eruption processes. Finally, we compared the characteristics of lavas from two different sampling sites with contrasting long-term magma supply rates. Differences between lavas from each study site illustrate the significant effect of magma supply on the physical properties of the oceanic upper crust.     

A Snapshot of the Sun Near Solar Minimum: The Whole Heliosphere Interval

We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum.     

A new device for use in crushing rigid biomass and geological materials prior to compositional analysis

Traditional preparation of rigid material for compositional analysis has involved time-consuming and physically demanding grinding processes, such as the use of mortar and pestle. This paper describes a simple and relatively inexpensive new device capable of quickly, safely, and efficiently pulverizing rigid and brittle biomass material, or geologic materials, such as rock and sediment. The high sample recovery obtained with this device is comparable to that achieved by much more expensive analytical equipment.     

Double vagueness: uncertainty in multi-scale fuzzy assignment of duneness

In the automation of identification of landscape features the vagueness arises from the fact that the attributes and parameters that make up a landscape vary over space and scale. In most of existing studies, these two kinds of vagueness are studied separately. This paper investigates their combination in identification of coast landscape units. Fuzzy set theory is used to describe the vagueness of geomorphic features due to the continuity in space. The vagueness resulted from the scale of measurement is evaluated by statistic indicators. The differences of fuzzy objects derived from data at differing resolutions (in size from 3×3 cells to 25×25 cells) are studied in order to examine these higher-order uncertainties.     

Dynamic weather forecaster: results of the testing of a collaborative, on-line educational platform for weather forecasting

The online Dynamic Weather Forecaster is an open, collaborative application available now to high-school and college instructors across the United States who would like to easily incorporate weather forecasting in their instruction. The application consists of a set of 13 questions that allow students to submit forecasts that cover most of the parameters used by professional weather forecasters. Submissions are automatically validated against weather parameters and graded. We tested the impact of the application on the learning of 199 undergraduate students in an introductory meteorology course in spring 2008. Students who begin forecasting early in the semester and continue to do so throughout the semester are statistically significantly more successful in the course than students who start late or complete a low number of forecasts. College, year in school, and gender were not significant predictors of success. Students found the application easy to use, and 92.3% of them found it at least somewhat helpful as they learned about the weather. Through the use of the DWF, students also experience first-hand that uncertainty is a critical part of weather forecasting and of scientific studies in general. With sufficient interest from potential users outside the USA, the DWF platform could easily be expanded to include global weather data.