Phytoplankton carbon fixation chlorophyll-biomass and diagnostic pigments in the Atlantic Ocean

We have made daily measurements of phytoplankton pigments, size-fractionated (<2 and >2-μm) carbon fixation and chlorophyll-a concentration during four Atlantic Meridional Transect (AMT) cruises in 2003–04. Surface rates of carbon fixation ranged from <0.2-mmol C m−3 d−1 in the subtropical gyres to 0.2–0.5-mmol C m−3 d−1 in the tropical equatorial Atlantic. Significant intercruise variability was restricted to the subtropical gyres, with higher chlorophyll-a concentrations and carbon fixation in the subsurface chlorophyll maximum during spring in either hemisphere. In surface waters, although picoplankton (<2-μm) represented the dominant fraction in terms of both carbon fixation (50–70%) and chlorophyll-a (80–90%), nanoplankton (>2-μm) contributions to total carbon fixation (30–50%) were higher than to total chlorophyll-a (10–20%). However, in the subsurface chlorophyll maximum picoplankton dominated both carbon fixation (70–90%) and chlorophyll-a (70–90%). Thus, in surface waters chlorophyll-normalised carbon fixation was 2–3 times higher for nanoplankton and differences in picoplankton and nanoplankton carbon to chlorophyll-a ratios may lead to either higher or similar growth rates. These low chlorophyll-normalised carbon fixation rates for picoplankton may also reflect losses of fixed carbon (cell leakage or respiration), decreases in photosynthetic efficiency, grazing losses during the incubations, or some combination of all these. Comparison of nitrate concentrations in the subsurface chlorophyll maximum with estimates of those required to support the observed rates of carbon fixation (assuming Redfield stoichiometry) indicate that primary production in the chlorophyll maximum may be light rather than nutrient limited.

The type I antifreeze protein gene family in Pleuronectidae

Antifreeze proteins (AFPs) protect marine teleosts from freezing in icy seawater by binding to nascent ice crystals and preventing their growth. It has been suggested that the gene dosage for AFPs in fish reflects the degree of exposure to harsh winter climates. The starry flounder, _Platichthys stellatus_, has been chosen to examine this relationship because it inhabits a range of the Pacific coast from California to the Arctic. This flatfish is presumed to produce type I AFP, which is an alanine-rich, amphipathic alpha-helix. Genomic DNA from four starry flounder was Southern blotted and probed with a cDNA of a winter flounder liver AFP. The hybridization signal was consistent with a gene family of approximately 40 copies. Blots of DNA from other starry flounder indicate that California fish have far fewer gene copies whereas Alaska fish have far more. This analysis is complicated by the fact that there are three different type I AFP isoforms. The first is expressed in the liver and secreted into circulation, the second is a larger hyperactive dimer also thought to be expressed in the liver, and the third is expressed in peripheral tissues. To evaluate the contribution of these latter two isoforms to the overall gene signal on Southern blots, hybridization probes for the three isoforms were isolated from starry flounder DNA by genomic cloning. Two clones revealed linkage of genes for different isoforms, and this was confirmed by genomic Southern blotting, where hybridization patterns indicated that the majority of genes were present in tandem repeats. The sequence and diversity of all three isoforms was sampled in the starry flounder genome by PCR. All coding sequences derived for the skin and liver isoforms were consistent with the proposed structure-function relationships for this AFP, where the flat hydrophobic side of the helix is conserved for ice binding. There was greater sequence diversity in the skin and hyperactive isoforms than in the liver isoform, suggesting that the latter evolved recently from one of the other two. The genomic PCR primers are currently being used to sample isoform diversity in related right-eyed flounders to test this hypothesis.

Structure of Ionic Liquid-Benzene Mixtures

Neutron diffraction has been used to investigate the structure of liquid mixtures of 1,3-dimethylimidazolium hexafluorophosphate with benzene. Two concentrations of benzene were investigated, namely, 33 mol % and 67 mol %, and show similar structures in each case. The presence of benzene significantly alters the ionic liquid structure, in particular, in the cation-cation interactions, in agreement with the single-crystal structure described recently (Holbrey, J. D.; Reichert, W. M.; Nieuwenhuyzen, M.; Sheppard, O.; Hardacre, C.; Rogers, R. D. Chem. Commun. 2003, 476). In each case, the data was analyzed using an empirical potential structure refinement process.

University students with disabilities in Universities. A study of their inclusion

Access to higher education has increased among students with disabilities, and universities are adopting different alternatives which must be assessed. The purpose of this study was to identify the situation of a sample of students with disabilities (n=91) who attend a university in Spain, through the design and validation of the “CUNIDIS-d” scale, with satisfactory psychometric properties. The results show the importance of making reasoned curriculum adaptations, adapting teacher training, improving accessibility and involving all the university community. Different proposals were provided which support the social dimension of the EHEA.

Molecular basis for estrogen receptor alpha deficiency in BRCA1-linked breast cancer

Background BRCA1-mutant breast tumors are typically estrogen receptor alpha (ER alpha) negative, whereas most sporadic tumors express wild-type BRCA1 and are ER alpha positive. We examined a possible mechanism for the observed ER alpha-negative phenotype of BRCA1-mutant tumors.

Methods We used a breast cancer disease-specific microarray to identify transcripts that were differentially expressed between paraffin-embedded samples of 17 BRCA1-mutant and 14 sporadic breast tumors. We measured the mRNA levels of estrogen receptor 1 (ESR1) ( the gene encoding ER alpha), which was differentially expressed in the tumor samples, by quantitative polymerase chain reaction. Regulation of ESR1 mRNA and ER alpha protein expression was assessed in human breast cancer HCC1937 cells that were stably reconstituted with wild-type BRCA1 expression construct and in human breast cancer T47D and MCF-7 cells transiently transfected with BRCA1-specific short-interfering RNA ( siRNA). Chromatin immunoprecipitation assays were performed to determine if BRCA1 binds the ESR1 promoter and to identify other interacting proteins. Sensitivity to the antiestrogen drug fulvestrant was examined in T47D and MCF-7 cells transfected with BRCA1-specific siRNA. All statistical tests were two-sided.

Results Mean ESR1 gene expression was 5.4-fold lower in BRCA1-mutant tumors than in sporadic tumors ( 95% confidence interval [CI]=2.6-fold to 40.1-fold, P =.0019). The transcription factor Oct-1 recruited BRCA1 to the ESR1 promoter, and both BRCA1 and Oct-1 were required for ER alpha expression. BRCA1-depleted breast cancer cells expressing exogenous ER alpha were more sensitive to fulvestrant than BRCA1-depleted cells transfected with empty vector ( T47D cells, the mean concentration of fulvestrant that inhibited the growth of 40% of the cells [IC40] for empty vector versus ER alpha: > 10(-5) versus 8.0 x 10(-9) M [ 95% CI=3.1x10(-10) to 3.2 x 10(-6) M]; MCF-7 cells, mean IC40 for empty vector versus ER alpha : > 10(-5) versus 4.9 x 10(-8) M [ 95% CI=2.0 x 10(-9) to 3.9 x 10(-6) M]).

Conclusions BRCA1 alters the response of breast cancer cells to antiestrogen therapy by directly modulating ER alpha expression.

Transition phenomena in a radio-frequency inductively coupled plasma

Changes of the electron dynamics during the mode transition (E- to H-mode) in a hydrogen radio-frequency (rf) inductively coupled plasma are investigated using space and phase resolved optical emission spectroscopy. The E- mode is characterized through relatively weak optical emission which is strongly modulated on a nanosecond time scale during the rf-cycle, with one pronounced maximum per cycle. The modulation in H-mode, with twice the rf-frequency, is significantly weaker while the emission intensities are about two orders of magnitude higher. In particular the transition between these two modes is studied under variations of rf-power input and gas pressure. Characteristic spatio-temporal structures are observed and can be understood in the frame of a simple model combining both coupling mechanisms in the transition regime.

A contingent valuation of the 2012 London Olympic games - A regional perspective

Major sporting events such as the Olympics are usually assessed in terms of economic impacts. Recently, policy makers have begun to place greater emphasis on possible intangible effects (such as civic pride, legacy of sporting facilities) associated with such events. To date, little work has been carried out on quantifying these effects in a meaningful way. This study uses contingent valuation methodology to assess the value of the proposed 2012 London Olympic Games. The survey is carried out on the provincial city of Bath, approximately 2 hours west of London. Conducting the survey outside of London is justified on the basis that the organizers of London 2012 have emphasized the value of the event to the United Kingdom as a whole. The results suggest that positive intangible effects are associated with the event and residents outside of London are willing to pay toward funding.