We measure linear optical dispersion, nonlinear refraction and two-photon absorption in a silicon waveguide at 1.54 μm wavelength. The total dispersion in the silicon waveguide was found to be −9.1 fs/(nm cm). At 1.54 μm wavelength, the two-photon absorption coefficient was found to be 0.45 cm/GW and a π phase shift from self-phase modulation was observed in optical pulses of 60 W peak-coupled power, generated from an amplified gain-switched laser diode.

Aquatic primary productivity is frequently limited by the availability of nutrients. The ability to identify factors limiting algal growth is of considerable importance to our understanding of the ecology of aquatic plants and to water management practices. Methods used to identify limiting resources in the past have included a) analysis of nutrient availability, b) elemental composition and cell quotas for various nutrients, c) bio-assays monitoring growth of test species or of natural populations following nutrient enrichment and d) measurements of various physiological parameters, such as enhancement of respiration and dark carbon fixation rates and perturbation of photosynthetic rate following re-supply of nutrients.In this paper we briefly review the merits and methodological limitations of these approaches for the assessment of the nutrient status of algal populations. We discuss how an understanding of biochemical and metabolic changes induced by nutrient limitation has led to the development of rapid and simple tools to monitor the nutrient status of aquatic plants and algae. In particular, we describe the use of transient changes in chlorophyll a fluorescence as a potential tool for rapid assessment of algal nutrient status and the development of molecular probes specific to nutrient limited cells, such as flavodoxin as a diagnostic tool for Fe-limitation.

This article contributes to the literature concerning the construction of working-class masculine identity in a context of unprecedented social transformation. Drawing on qualitative interviews with 24 young men currently employed in the retail sector, this study finds that contrary to much research on masculinities young working-class men are able to resist dominant and hegemonic cultural ideals. The respondents demonstrate a very different attitude towards the 'emotional labour' required in the service sector than is often documented, while also rejecting notions of traditional gendered domestic responsibilities in respect of their futures as potential partners and parents. Congruent with other emerging research in this area, the reference point for an 'acceptable' masculine identity appears to have shifted, with some young working-class men's lives, at least, illustrating an attenuated or softened version of masculinity.

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1. Urbanisation is an important cause of eutrophication in waters draining urban areas. We determined whether benthic algal biomass in small streams draining urban areas was explained primarily by small-scale factors (benthic light, substratum type and nutrient concentrations) within a stream, or by catchment-scale variables that incorporate the interacting multiple impacts of urbanisation (i.e. variables that describe urban density and the intensity of drainage or septic tank systems). 2. Benthic algal biomass was assessed as chlorophyll a density (chl a) in 16 streams spanning a rural-urban gradient, with both a wide range of urban density and of piped stormwater infrastructure intensity on the eastern fringe of metropolitan Melbourne, Australia. The gradient of urban density among streams was broadly correlated with catchment imperviousness, drainage connection (proportion of impervious areas connected to streams by stormwater pipes), altitude, longitude and median phosphorus concentration. Catchment area, septic tank density, median nitrogen concentration, benthic light (photosynthetically active radiation) and substratum type were not strongly correlated with the urban gradient. 3. Variation in benthic light and substratum type within streams explained a relatively small amount of variation in log chl a (3-11 and 1-13%, respectively) compared with between-site variation (39-54%). 4. Median chl a was positively correlated with catchment urbanisation, with a large proportion of variance explained jointly (as determined by hierarchical partitioning) by those variables correlated with urban density. Independent of this correlation, the contributions of drainage connection and altitude to the explained variance in chl a were significant. 5. The direct connection of impervious surfaces to streams by stormwater pipes is hypothesised as the main determinant of algal biomass in these streams through its effect on the supply of phosphorus, possibly in interaction with stormwater-related impacts on grazing fauna. Management of benthic algal biomass in streams of urbanised catchments is likely to be most effective through the application of stormwater management approaches that reduce drainage connection.

This paper presents the results of studies into the use of the emerging techniques of nutrient induced fluorescence transients (NIFTs) and Fourier Transform InfraRed (FTIR) spectroscopy to determine the nutrient status of microalgae. Four species of microalgae were grown under conditions where growth rate was P-limited or P-replete, and NIFT responses and FTIR spectra in response to the re-supply of P (as PO 4 3-) measured. These responses were compared to more conventional measures of algal nutrient status such as P-uptake rates, P quotas and transient effects of PO 4 3-on oxygen exchange. The NIFT technique and FTIR spectroscopy gave results that were consistent with those obtained by the other techniques. Furthermore, we were able to demonstrate NIFT responses in phytoplankton samples taken from Lake Lucerne (total ambient P ≤ 0.13 µM) but not from Lake Zürich (total P 0.55 µM). The potential and limitations of the various techniques are discussed.

This paper examines contemporary gender relations among young people by taking young men's experiences with and understandings of 'sexting' as a case in point. Based on a focus group study with university undergraduate men in Melbourne, Australia, we analyse what is seen as having value and what is seen as constituting a risk when engaging in sexting, and how this is perceived as different for men and women. We demonstrate how value and risk are closely intertwined in the focus group discussions and how the body is central in the production and negotiation of both these dimensions. This is made particularly clear in the two 'figures' that participants described as embodying the perceived risks; 'the creep' and 'the slut'. This paper illustrates the ways gendered bodies and sexual value are central to the ways 'double standards' operate in sexting and persist in contemporary gender relations.

In this semi-structured interview research, we investigate the attitudes of 22 academy-level association football (soccer) players who are potentially on the verge of becoming professional athletes. We find that, as a result of these men belonging to a generation holding inclusive attitudes towards homosexuality, independent of whether they maintain contact with gay men, they are unanimously supportive of gay men coming out on their team. Thus, this research supports a growing body of literature suggesting that teamsport culture is no longer a bastion of homophobia in the UK. Their support includes athletes being unconcerned with sharing rooms with gay players, changing with them in the locker rooms, or relating to them on a social and emotional level. The only apprehension they maintain is that having a gay teammate might somewhat alter homosocial banter, as they would not want to offend that individual.