Survey of fishes and water properties of south San Francisco Bay, California, 1973-82

The objective of this study was to describe the physical and ichthyological changes occurring seasonally and annually in the south San Francisco Bay, based on the results of 2,561 otter trawl and water samples obtained between February 1973 and June 1982. Temperature varied predictably among seasons in a pattern that varied little between years. Salinity also underwent predictable seasonal changes but the pattern varied substantially between years. The most abundant species of fish were northern anchovy (Engraulis mordax), English sole (Parophrys vetulus), and shiner surfperch (Cymatogaster aggregata). The majority of the common fish species were most abundant during wet years and least abundant in dry years. Numeric diversity was highest during the spring and early summer, with no detectable interannual trends. Species composition changed extensively between seasons and between years, particularly years with extremely high or extremely low freshwater inflows. All the common species exhibited clustered spatial distributions. Such spatial clustering could affect the interpretation of data from estuarine sampling programs. Gobies (Family Gobiidae) were more abundant during flood tides than during ebb tides. English sole were significantly more abundant in shallower areas. Shiner surfperch showed significant differences in abundance between sample areas.(PDF file contains 28 pages.)

On the Selection of Non-Invasive Methods Based on Speech Analysis Oriented to Automatic Alzheimer Disease Diagnosis

The work presented here is part of a larger study to identify novel technologies and biomarkers for early Alzheimer disease (AD) detection and it focuses on evaluating the suitability of a new approach for early AD diagnosis by non-invasive methods. The purpose is to examine in a pilot study the potential of applying intelligent algorithms to speech features obtained from suspected patients in order to contribute to the improvement of diagnosis of AD and its degree of severity. In this sense, Artificial Neural Networks (ANN) have been used for the automatic classification of the two classes (AD and control subjects). Two human issues have been analyzed for feature selection: Spontaneous Speech and Emotional Response. Not only linear features but also non-linear ones, such as Fractal Dimension, have been explored. The approach is non invasive, low cost and without any side effects. Obtained experimental results were very satisfactory and promising for early diagnosis and classification of AD patients.

Falsche Fische – ein Bericht über die Schwierigkeiten der Identifizierung einer „Seezunge“

In the last years German food control laboratories have established proof of a significant number of cases of incorrectly labelled flatfish on the German market. A flatfish offered as sole (Solea vulgaris) in Southern Germany served as an example for mislabelled flatfish and for the difficulties food control laboratories may encounter and to identify products of unknown origin. Morphometric and meristic examination, as well as isoelectric focusing of sarcoplasmic proteins, PCR-based DNA-analysis failed to identify the fish. By using these methods, it only could be excluded that the fish belonged to the species of Solea vulgaris or another described flatfish species. DNA sequencing of an amplicon gave a sequence identical to a sequence in GenBank, which, however, turned out to be incorrectly assigned to Solea vulgaris. More research about characterization and identification of tropical flatfish is recommended, because of the growing importance of these fishes for the European market.

Wer fischt was? – Gemischte Bodenfischereien und ihre Auswirkungen auf die wichtigsten Nutzfischbestände in der Nordsee

Cod, haddock, whiting, saithe, plaice, sole and Norway lobster are 7 main target species of the demersal mixed fisheries in the North Sea, Skagerrak and Eastern Channel. Gadoids and Norway lobsters are mainly taken in the nor-thern North Sea by towed gears except beam trawls while the flatfish fisheries are conducted in the southern North Sea mainly using beam trawls. Recently, the central North Sea appears less fished by demersal gears. Towed nets including seines and beam trawls equipped with meshes of more than 100 mm resp. more than 80 mm were identified as the main gears effecting the depleted cod and reduced plaice stocks. The saithe sector, using towed nets with meshes of more than110 mm, longlines, gill nets and others, appears to affect the 7 species to a lesser extend. These results support the interim effort limitations by gear types, vessel and month as enforced by the European Commission since 2003. TAC regulations alone are considered inefficient to sustainably harvest stocks by mixed fisheries. A fleet-effort management method is developed estimating the fleets’ effects based on the sum of partial exploitation rates of the species in mixed fisheries weighted by the ratio of the precautionary reference Bpa and the actual SSB size as ecological quality objective. Applying such fleet effort management could result in increased catch possibilities of some stocks by fleets selecting mainly few and non-overexploited stocks while respecting precautionary management constraints in minimum SSB or maximum exploitation rates at the same time.

Dänemarks Fischereierträge 1996 konstant - aber deutlicher Anstieg 1997

Although landings in 1996 were 319 000 t down (–16 %) from 1995 the returns from fishery in 1996 were almost as high as 1995 ( 3014 mio. dkr; – 0.2 %). Industrial fishery alone decreased by 268 000 t. The average price for all landed species was 1.81 dkr/kg, an increase of 19 % compared to 1995, with a range of 0.61 dkr/kg for industrial fish (sandeel etc.) to 62 dkr/kg for sole. 1997 the fishery scene improved again. Already in November landings reached 1.74 mio. t, more than all 1996. Price increase was not as strong as 1996; on average 5 % until November. Total return until November was, however, alreday 3250 mio. dkr; 405 mio dkr above total return of 1996.

On the origin of shear banding instability in metallic glasses

To uncover the physical origin of shear-banding instability in metallic glass (MG), a theoretical description of thermo-mechanical deformation of MG undergoing one-dimensional simple shearing is presented. The coupled thermo-mechanical model takes into account the momentum balance, the energy balance and the dynamics of free volume. The interplay between free-volume production and temperature increase being two potential causes for shear-banding instability is examined on the basis of the homogeneous solution. It is found that the free-volume production facilitates the sudden increase in the temperature before instability and vice versa. A rigorous linear perturbation analysis is used to examine the inhomogeneous deformation, during which the onset criteria and the internal length and time scales for three types of instabilities, namely free-volume softening, thermal softening and coupling softening, are clearly revealed. The shear-banding instability originating from sole free-volume softening takes place easier and faster than that due to sole thermal softening, and dominates in the coupling softening. Furthermore, the coupled thermo-mechanical shear-band analysis does show that an initial slight distribution of local free volume can incur significant strain localization, producing a shear band. During such a localization process, the local free-volume creation occurs indeed prior to the increase in local temperature, indicating that the former is the cause of shear localization, whereas the latter is its consequence. Finally, extension of the above model to include the shear-induced dilatation shows that such dilatation facilitates the shear instability in metallic glasses.

A study on the growth of Pseudotolithus elongatus, Chrysichthys nigrodigitatus and Cynoglossus goreensis occurring in the Cross River Estuary

Samples of Pseudotolithus elongatus, Chrysichthys nigrodigitatus and Cynoglosus goreensis obtained from the Cross River Estuary (which is most probably the largest estuary water system along the coast of West Africa) between January 1980 and May 1981 were evaluated on basis of population dynamic analytical method postulated by Pauly (1980) for tropical fish stocks. Growth parameters were obtained for the fish species. Wherever possible, these results were compared to those obtained by Longhurst (1964d) and LeGuen (1971) in other West African waters. On the whole, results obtained in this study tend to indicate that the growth of the croaker, bagrid catfish and the sole in the Cross River Estuary is allometric, the third and fourth year-classes of P. elongatus the second and third class-year of C. nigrodigitatus and the fourth, fifth and sixth year classes of C. goreensis dominated in the age distribution of these fish species

An investigation of the effect of replacing fish meal with soyabean meal, groundnut cake and blood meal at varied proportion on growth and food utilization of the Clarias anguillaris fingerlings fed in outdoor hapas

Fingerlings of Clarias anguillaris obtained from a homogenous source through induce breeding and each with a mean weight of 2.8g were stocked in ten hapas each measuring 1.0x1.0m in outdoor concrete tank and were fed for eight (8) weeks. Results shows that the best growth rate was recorded among fingerlings fed fish meal as the only protein source (TD5) while DT2 containing soya bean, groundnut cake (40%), blood meal as the protein sources came next. The growth rate of fingerlings fed DT2 (40 % groundnut cake, 10% soyabean meal and 10% blood meal) was higher than those fed DT4 containing 10% fish meal but lower than those fed DT5 which has fish meal as its sole source of protein (53.0%). Analysis of various growth parameters like SGR, FCR and PER. shows that DT5 was the overall best diet but there was no significant statistical difference in weight gained by fish fed the five diets (P <0.05)

Die Entwicklung wichtiger Fischbestände in der Nordsee und im Nordatlantik. Ergebnisse der Herbstsitzung des Advisory Committees for Fishery Management des internationalen Rates für Meeresforschung

The October meeting of the ACFM of ICES gave advice for a number of North-Atlantic fish stocks. The results of the most important stocks are given here from the perspective of German fishery management. The are chiefly North Sea plaice and sole, for which a reduction of 25 % of the fishing mortality (F) is recommended for 1998, North Sea saithe (minus 20 % in F), while North Sea cod is in the process of recovery and North Sea haddock is inside safe biological limits. The mackerel stock of the North Sea has not yet recovered, while the western mackerel stock as an entity has stabilised at a level of about 2.3 million t.

The LIN-3 gene of the nematode C. elegans is the vulval-inducing signal

The development of the vulva of the nematode Caenorhabditis elegans is induced by a signal from the anchor cell of the somatic gonad. Activity of the gene lin-3 is required for the Vulval Precursor Cells (VPCs) to assume vulval fates. It is shown here that lin-3 encodes the vulval-inducing signal.

lin-3 was molecularly cloned by transposon-tagging and shown to encode a nematode member ofthe Epidermal Growth Factor (EGF) family. Genetic epistasis experiments indicate that lin-3 acts upstream of let-23, which encodes a homologue of the EGF-Receptor.

lin-3 transgenes that contain multiple copies of wild-type lin-3 genomic DNA clones confer a dominant multivulva phenotype in which up to all six of the VPCs assume vulval fates. The properties of these trans genes suggest that lin-3 can act in the anchor cell to induce vulval fates. Ablation of the gonadal precursors, which prevents the development of the AC, strongly reduces the ability of lin-3 transgenes to stimulate vulval development. A lin-3 recorder transgene that retains the ability to stimulate vulval development is expressed specifically in the anchor cell at the time of vulval induction.

Expression of an obligate secreted form of the EGF domain of Lin-S from a heterologous promoter is sufficient to induce vulval fates in the absence of the normal source of the inductive signal. This result suggests that Lin-S may act as a secreted factor, and that Lin-S may be the sole vulval-inducing signal made by the anchor cell.

lin-3 transgenes can cause adjacent VPCs to assume the 1° vulval fate and thus can override the action of the lateral signal mediated by lin-12 that normally prevents adjacent 1° fates. This indicates that the production of Lin-3 by the anchor cell must be limited to allow the VPCs to assume the proper pattern of fates of so 3° 3° 2° 1° 2° 3°.

Export potential of ornamental live fishes in Nigeria

Nigeria is blessed with an abundant variety of fish species, some of which have been exported over the years. These fish species are taken either from the wild or cultured. Large quantities of fishes and fishery products are exported from Nigeria in different forms and which have been sources of foreign exchange earnings for the Country. An estimate value of exports in the fishery sub-sector stood at approximately U.S. $48.212,070 for shrimps/sole fish/cuttlefish/crabs and over U.S.$500,000 for ornamental live fishes

Perspektiven für den Schwarmfischfang in den Gewässern westlich der Britischen Inseln und der Biskaya

FRV "Walther Herwig" participated in a survey internationally coordinated by ICES in waters west of the British Isles and the Gulf of Biscay from February 14 to March 5. Results are given especially on mackerel and horse mackerel from the Hebrides area, west of Ireland, Great and Littie Sole Bank, and Eddystone.

Magnetohydrodynamic turbulence

We simulate incompressible, MHD turbulence using a pseudo-spectral code. Our major conclusions are as follows.

1) MHD turbulence is most conveniently described in terms of counter propagating shear Alfvén and slow waves. Shear Alfvén waves control the cascade dynamics. Slow waves play a passive role and adopt the spectrum set by the shear Alfvén waves. Cascades composed entirely of shear Alfvén waves do not generate a significant measure of slow waves.

2) MHD turbulence is anisotropic with energy cascading more rapidly along k_⊥ than along k_∥, where k_⊥ and k_∥ refer to wavevector components perpendicular and parallel to the local magnetic field. Anisotropy increases with increasing k_⊥ such that excited modes are confined inside a cone bounded by k_∥ ∝ k^γ_⊥ where γ less than 1. The opening angle of the cone, θ(k_⊥) ∝ k^-(1-γ)_⊥, defines the scale dependent anisotropy.

3) MHD turbulence is generically strong in the sense that the waves which comprise it suffer order unity distortions on timescales comparable to their periods. Nevertheless, turbulent fluctuations are small deep inside the inertial range. Their energy density is less than that of the background field by a factor θ² (k_⊥)≪1.

4) MHD cascades are best understood geometrically. Wave packets suffer distortions as they move along magnetic field lines perturbed by counter propagating waves. Field lines perturbed by unidirectional waves map planes perpendicular to the local field into each other. Shear Alfvén waves are responsible for the mapping's shear and slow waves for its dilatation. The amplitude of the former exceeds that of the latter by 1/θ(k_⊥) which accounts for dominance of the shear Alfvén waves in controlling the cascade dynamics.

5) Passive scalars mixed by MHD turbulence adopt the same power spectrum as the velocity and magnetic field perturbations.

6) Decaying MHD turbulence is unstable to an increase of the imbalance between the flux of waves propagating in opposite directions along the magnetic field. Forced MHD turbulence displays order unity fluctuations with respect to the balanced state if excited at low k by δ(t) correlated forcing. It appears to be statistically stable to the unlimited growth of imbalance.

7) Gradients of the dynamic variables are focused into sheets aligned with the magnetic field whose thickness is comparable to the dissipation scale. Sheets formed by oppositely directed waves are uncorrelated. We suspect that these are vortex sheets which the mean magnetic field prevents from rolling up.

8) Items (1)-(5) lend support to the model of strong MHD turbulence put forth by Goldreich and Sridhar (1995, 1997). Results from our simulations are also consistent with the GS prediction γ = 2/3. The sole not able discrepancy is that the 1D power law spectra, E(k_⊥) ∝ k^-∝_⊥, determined from our simulations exhibit ∝ ≈ 3/2, whereas the GS model predicts ∝ = 5/3.

Relação dos sistemas de reparo de DNA em Escherichia coli K-12 com resistência a antibióticos, características adesivas e formação de biofilme

As espécies reativas de oxigênio (ERO) são geradas durante o metabolismo celular normal e podem produzir vários danos oxidativos no DNA, tais como lesões nas bases nitrogenadas ou sítios apurínico/apirimidínico (AP). Essas lesões podem acarretar acúmulo de sítios de mutações, caso esses danos não sejam reparados. Entretanto, as bactérias possuem vários mecanismos de defesa contra as ERO que desempenham um importante papel na manutenção da fisiologia. O objetivo deste trabalho foi o de avaliar se sistemas enzimáticos, como o reparo por excisão de bases (BER), sistema SOS e SoxRS, interferem em respostas como a sensibilidade aos antibióticos, aderência das células bacterianas a superfícies bióticas ou abióticas e formação de biofilme. Os mutantes utilizados no presente estudo são todos derivados de Escherichia coli K-12 e os resultados obtidos mostraram que, dos mutantes BER testados, o único que apresentou diferença no perfil de sensibilidade aos antimicrobiamos em relação à cepa selvagem (AB1157) foi o mutante xthA- (BW9091), deficiente em exonuclease III. No teste de aderência qualitativo realizado com linhagem de células HEp-2 (originária de carcinoma de laringe humana) foi observado que onze cepas da nossa coleção, apresentaram um padrão denominando like-AA, contrastando com o que era esperado para as cepas de E. coli utilizadas como controle negativo, que apresentam aderência discreta sem padrão típico. A aderência manose-sensível via fímbria do tipo I avaliada nesse estudo mostrou que essa fimbria, possui um papel relevante na intensidade da aderência e filamentação nessas cepas estudas. A filamentação é uma resposta SOS importante para que o genoma seja reparado antes de ser partilhado pelas células filhas. Além disso, com relação à formação de biofilme, oito cepas apresentaram um biofilme forte sendo que essa resposta não foi acompanhada pelo aumento da intensidade de filamentação. Nossos resultados em conjunto sugerem o envolvimento de estresse oxidativo na definição de parâmetros como sensibilidade a antimicrobianos, padrão e intensidade de aderência, filamentação e formação de biofilme nas amostras de E. coli K-12 avaliadas neste trabalho. Sugerimos que a aderência gera estresse oxidativo causando danos no DNA, o que leva a indução do sistema SOS resultando na resposta de filamentação observada.

Fish diversity of the wild and aquaculture water bodies in Singida Region

Tanzania Fisheries Research Institute being currently the only fisheries research institute in Tanzania has sole responsibility of marking the presence and distribution of fish species in the country. This work is expected to be completed by the year 2005. In order that this work can be accomplished, both published works and field observations (including geographical location using GPS) have to be compiled. Since the institute has centers in all the Great Lakes and one along the Indian Ocean coast, it is expected that field observations and identifications will be obtained and incorporated into the document to be produced by 2005. (PDF contains 15 pages)