Interannual variability of marine zooplankton and their environments: Within- and between-region comparisons

The work highlights the first Global Comparison of Zooplankton Time Series. ► Variation of the peak in abundance is affected by annual temperature anomalies. ► Results show no global-scale synchrony in zooplankton time-series. ► There are spatial autocorrelations over substantial distances (1000–3000 km). ► There remains considerable uncertainty about the relative causes of shifts in distributions.

Volcanic ash supply to the surface ocean – remote sensing of biological responses and their wider biogeochemical significance

Transient micronutrient enrichment of the surface ocean can enhance phytoplankton growth rates and alter microbial community structure with an ensuing spectrum of biogeochemical feedbacks. Strong phytoplankton responses to micronutrients supplied by volcanic ash have been reported recently. Here we: (i) synthesize findings from these recent studies; (ii) report the results of a new remote sensing study of ash fertilization; and (iii) calculate theoretical bounds of ash-fertilized carbon export. Our synthesis highlights that phytoplankton responses to ash do not always simply mimic that of iron amendment; the exact mechanisms for this are likely biogeochemically important but are not yet well understood. Inherent optical properties of ash-loaded seawater suggest rhyolitic ash biases routine satellite chlorophyll-a estimation upwards by more than an order of magnitude for waters with <0.1 mg chlorophyll-a m-3, and less than a factor of 2 for systems with >0.5 mg chlorophyll-a m-3. For this reason post-ash-deposition chlorophyll-a changes in oligotrophic waters detected via standard Case 1 (open ocean) algorithms should be interpreted with caution. Remote sensing analysis of historic events with a bias less than a factor of 2 provided limited stand-alone evidence for ash-fertilization. Confounding factors were poor coverage, incoherent ash dispersal, and ambiguity ascribing biomass changes to ash supply over other potential drivers. Using current estimates of iron release and carbon export efficiencies, uncertainty bounds of ash-fertilized carbon export for 3 events are presented. Patagonian iron supply to the Southern Ocean from volcanic eruptions is less than that of windblown dust on thousand year timescales but can dominate supply at shorter timescales. Reducing uncertainties in remote sensing of phytoplankton response and nutrient release from ash are avenues for enabling assessment of the oceanic response to large-scale transient nutrient enrichment.

Quantification of urinary excretion of ethosuximide enantiomers and their major metabolites in the rat.

A chiral gas chromatographic assay has been developed for quantitative analysis of ethosuximide and its major metabolites in rat urine. The extraction procedure was found to be precise and reproducible. Recovery was in the range of 94-98%, intraday CV(%) was 0.92% for (S)-ethosuximide (50 mug/ml) and 0.51% for (R)-ethosuximide (50 mug/ml). Interday CV(%) was 1.12% for (S)-ethosuximide and 0.72% for (R)-ethosuximide. The limit of detection was determined to be around 0.01 mug/ml for each enantiomer. Following administration of rac-ethosuximide by i.v., i.p. and oral routes, unchanged ethosuximide was detected in urine up to 72h after drug administration. The appearance of all detected metabolites occurred Within 24h of drug administration. Significantly more (S)-ethosuximide was excreted unchanged than (R)-ethosuximide with all three routes studied. A substantial amount of the drug was eliminated as the 2-(1-hydroxyethyl)-2-methylsuccinimide (2 pairs of diastereoisomers). Much less drug was eliminated as the 2-ethyl-3-hydroxy-2-methylsuccinimide with only one diastereoisomer observed. Examination of the one pair of diastereoisomers of 2-(1-hydroxyethyl)-2-methylsuccinimide that was resolved showed preferential excretion of one isomer. Comparison of both pairs of diastereoisomers showed that one pair was formed in preference to the other with a ratio of approximately 0.8:1. It is concluded that stereoselective metabolism of ethosuximide occurs. Copyright (C) 2001 John Wiley & Sons, Ltd. Author Keywords: chiral pharmacokinetics; ethosuximide enantiomers; metabolism; rat; urinary excretion; gas chromatography

The Development of Credit Unions and their Role in Tackling Financial Exclusion

The government has been actively encouraging the development of credit unions to help the financially excluded. However, rather than stimulating credit union development, government grants can erode the community self-help ethos on which credit unions are founded. Policies should be formulated which encourage credit union development based on a membership drawn from a cross-section of the population.

Teachers’ perception of visual deficiencies and their impact on students

The sense of vision is people’s main source of information acquisition, hence the importance of a right diagnosis and correction, if necessary, of any faults for proper learning, especially in the early years of schooling. This article discusses the results of a survey of teachers in Andalusian schools that aimed at highlighting their knowledge of their students’ possible visual deficiencies, and its possible impact on school performance. The results indicate that such knowledge is generally limited to the type of refractive anomalies, and that they think that such anomalies are well treated in their students. Despite the importance they attach to these deficiencies on school learning, they think that other factors may have a greater role. They also consider that better training on this topic is necessary.

syn-Benzene dioxides: chemoenzymatic synthesis from 2,3-cis-dihydrodiol derivatives of monosubstituted benzenes and their application in the synthesis of regioisomeric 1,2- and 3,4-cis-dihydrodiols and 1,4-dioxocins

cis-2,3-Dihydrodiol metabolites of monosubstituted halobenzenes and toluene have been used as synthetic precursors of the corresponding 3,4-cis-dihydrodiols. Enantiopure syn-benzene dioxide intermediates were reduced to the 3,4-cis-dihydrodiols and thermally racemised via the corresponding 1,4-dioxocins. The syn-benzene dioxide-1,4-dioxocin valence tautomeric equilibrium ratio was found to be dependent on the substituent position. The methodology has also been applied to the synthesis of both enantiomers of the 1,2-(ipso)- and 3,4-cis-dihydrodiols of toluene. This chemoenzymatic approach thus makes available, for the first time, all three possible cis-dihydrodiol regioisomers of a monosubstituted benzene.

Acoustic features of song categories and their possible implications for communication in the common nightingale (Luscinia megarhynchos)

In many passerine species, males sing more than one distinct song type. Commonly, songs are assigned to different song types or song categories based on phonological and syntactical dissimilarities. However, temporal aspects, such as song length and song rate, also need to be considered to understand the possible functions of different songs. Common nightingales (Luscinia megarhynchos) have large vocal repertoires of different song types but their songs additionally can be grouped into two distinct categories (particular groups of song types): whistle songs and nonwhistle songs. Whistle songs are hypothesised to be important to attract migrating females. We studied temporal properties of whistle songs and nonwhistle songs and examined the relationship between those song parameters and song output parameters, such as song rate and song length. To investigate how song parameters vary among males, we calculated the coefficients of variation for different song traits. We found that the variation in the proportion of whistle songs was significantly higher among males than variation in other song parameters. Furthermore, the proportion of whistle songs was negatively correlated with other sona output patterns. These findings suggest that the production of whistle songs might be constrained and/or that whistle songs and their succeeding pauses may act as a functional unit in communication.

Softened C-H modes of adsorbed methyl and their implications for dehydrogenation: An ab initio study

To investigate the softening of CH vibrational frequencies and their implications for dehydrogenation of adsorbed hydrocarbons, an issue of scientific and technological importance, density functional theory calculations have been performed on the chemisorption and dehydrogenation of CH3 on Cu(111) and Pt(111) surfaces. By comparing these results with those of Ni(111) we find that the CH bonds of the adsorbate, when close enough, interact with metal atoms of the surface. It is this interaction and its associated lengthening and weakening of CH bonds that is the physical origin of mode softening. We rule out the possibility of a relationship between the mere presence of mode softening and dehydrogenation. We do show, however, that there is a clear relationship between the extent to which a surface can induce mode softening and the activation energy to dehydrogenation. In addition, periodic trends concerning the extent of mode softening are reproduced. (C) 2001 American Institute of Physics.

The pathophysiology of HOX genes and their role in cancer

The HOM-C clustered prototype homeobox genes of Drosophila, and their counterparts, the HOX genes in humans, are highly conserved at the genomic level. These master regulators of development continue to be expressed throughout adulthood in various tissues and organs. The physiological and patho-physiological functions of this network of genes are being avidly pursued within the scientific community, but defined roles for them remain elusive. The order of expression of HOX genes within a cluster is co-ordinated during development, so that the 3' genes are expressed more anteriorly and earlier than the 5' genes. Mutations in HOXA13 and HOXD13 are associated with disorders of limb formation such as hand-foot-genital syndrome (HFGS), synpolydactyly (SPD), and brachydactyly. Haematopoietic progenitors express HOX genes in a pattern characteristic of the lineage and stage of differentiation of the cells. In leukaemia, dysregulated HOX gene expression can occur due to chromosomal translocations involving upstream regulators such as the MLL gene, or the fusion of a HOX gene to another gene such as the nucleoporin, NUP98. Recent investigations of HOX gene expression in leukaemia are providing important insights into disease classification and prediction of clinical outcome. Whereas the oncogenic potential of certain HOX genes in leukaemia has already been defined, their role in other neoplasms is currently being studied. Progress has been hampered by the experimental approach used in many studies in which the expression of small subsets of HOX genes was analysed, and complicated by the functional redundancy implicit in the HOX gene system. Attempts to elucidate the function of HOX genes in malignant transformation will be enhanced by a better understanding of their upstream regulators and downstream target genes.