This paper analyses the spatial distribution of fishing effort in a sample of 25 Dutch commercial beam trawlers fishing for sole and plaice in the period 1993–1996, based on an automated recording ...system with an accuracy of about 0.1 nautical mile. Intensive fishing occurred along the borders of the closed areas (12 mile zone and the “plaice-box”, a protected area in the eastern part of the North Sea) and at certain off-shore grounds in the southern and central North Sea. Effort distribution was studied within 30 × 30 (ICES rectangles), 10 × 10, 3 × 3 and 1 × 1 nautical mile squares and showed a patchy distribution. The degree of patchiness decreased with resolution. Within 3 × 3 mile squares, beam trawling was randomly distributed in some parts of the most heavily fished ICES rectangles but patchily distributed in others. Within 1 × 1 mile squares, the distribution became random within more than 90% of the squares. The micro-distribution showed a remarkable similarity between the 4 years with a mean coefficient of overlap of 0.66, range 0.56–0.76. The micro-distribution of the sampled vessels was raised to the total Dutch fleet in order to estimate the frequency at which the sea bed was trawled. It was estimated that during the four year study period in eight of the most heavily fished rectangles of the North Sea, 5% of the surface area was trawled less than once in 5 years and 29% less than once in a year. The surface area of the sea bed that was trawled between 1 and 2 times in a year was estimated at 30%. The surface area trawled more than five times in a year was estimated at 9%. The relevance of the findings for the study of the impact of beam trawling on the benthic fauna is discussed.
The fishing pattern of individual beam trawl vessels comprises alternating searching and exploitation phases during a fishing trip. The searching phase is characterized by a below-average catch rate ...and a long distance between the midpoints of hauls. The exploitation phase is characterized by an above average-catch rate and a small inter-haul distance. During the exploitation of a local concentration of flatfish, the catch rate decreases on average by 10% over a period of 48 h. The rate of decline is a function of the engine power. Powerful vessels experience a small or no decline in catch rate, whereas less powerful vessels experience a decline of up to 16%. It is inferred that the decline in catch rate may be due to interference competition among vessels through a change in the behaviour of flatfish in response to fishing disturbance, although a reduction in local abundance may also have contributed to the decline. Areas with above-average catch rates may change on a weekly basis.
It is demonstrated that a grain size dependence exists for the rotational permeability of a series of MnZn polycrystalline ferrites, analogous to that predicted by the Globus model for wall ...permeability. To account for this behavior, a model has been developed which considers crystalline ferrite grains with intrinsic complex permeability, mu /sub i/, surrounded by thin, nonmagnetic grain boundaries. The effectively measured permeability of the polycrystal ( mu /sub e/) is related in the model to the intrinsic permeability, the grain size (D), and the grain boundary thickness ( delta ) according to the equation mu /sub e/= mu /sub i/D/ mu /sub i/ delta +D. The almost linear dependence of permeability with grain size for fine-grained polycrystals emerges if one considers the limit where D is so small that D<< mu /sub i/ delta , and consequently mu /sub e/=D/ delta (providing delta remains constant). For large grains, where D>> mu /sub i/ delta , it is found that the model predicts a constant rotational permeability equivalent to that in a single crystal of the same material. In the situation where the intrinsic permeability of the ferrite displays a relaxational behavior and follows the Snoeks relationship, it is found that both the low-frequency permeability and the resonance frequency of the polycrystal are modified, but in a manner whereby the Snoeks relationship remains valid.< >
A method that can be used to measure the absolute efficiency of narrow-track magnetic heads such as video heads (gap area <10 3 (μm) 2 ) is described. The method is based on the detection of the gap ...flux by means of a subsidiary coil wound around the gap. Usually a considerable amount of leakage flux is detected together with the gap flux, which obviously would impair the accuracy of the results. Therefore, measures were taken by raising the current through the main coil progressively and thus determining the saturation value of the gap flux. In this way it was possible to distinguish between the gap flux and leakage flux components. With this method the efficiency can be measured with an accuracy of better than 10 percent at frequencies of up to 10 MHz. As a second result, the gap area can thus be determined magnetically as well. A comparison of the magnetic and optical gap area offers a check on the reliability of the efficiency measurement. The merits of this measuring method are discussed with the aid of results obtained for a typical ferrite video head.
Polycystic ovary syndrome (PCOS) is a common reproductive disorder associated with many characteristic features, including hyperandrogenaemia, insulin resistance and obesity which may have ...significant implications for pregnancy outcomes and long-term health of the woman. This meta-analysis was conducted to evaluate the risk of pregnancy and neonatal complications in women with PCOS. Electronic databases were searched for the following MeSH headings: PCOS, hyperandrogenism, pregnancy outcome, pregnancy complications, diabetes mellitus, type II. A handsearch of human reproduction and fertility and sterility was also conducted. Studies in which pregnancy outcomes in women with PCOS were compared with controls were considered for inclusion in this meta-analysis. Fifteen of 525 identified studies were included, involving 720 women presenting with PCOS and 4505 controls. Women with PCOS demonstrated a significantly higher risk of developing gestational diabetes odds ratio (OR) 2.94; 95% confidence interval (CI): 1.70–5.08, pregnancy-induced hypertension (OR 3.67; 95% CI: 1.98–6.81), pre-eclampsia (OR 3.47; 95% CI: 1.95–6.17) and preterm birth (OR 1.75; 95% CI: 1.16–2.62). Their babies had a significantly higher risk of admission to a neonatal intensive care unit (OR 2.31; 95% CI: 1.25–4.26) and a higher perinatal mortality (OR 3.07; 95% CI: 1.03–9.21), unrelated to multiple births. In conclusion, women with PCOS are at increased risk of pregnancy and neonatal complications. Pre-pregnancy, antenatal and intrapartum care should be aimed at reducing these risks.
Abstract Endocrine effects of the brominated flame retardant tetrabromobisphenol-A (TBBPA) were studied in a one-generation reproduction assay in Wistar rats via repeated dietary exposure, applying ...eight dose groups at 0–3–10–30–100–300–1000–3000 mg/kg body weight/day (mkd). This design enables dose–response analysis and calculation of benchmark doses (BMDL). This reproduction study was preceded by a 28-day repeat dose subacute toxicity study, at 0–30–100–300 mkd. Major effects in the reproduction study included decreased circulating thyroxine (T4) with BMDLs of 31 (m) and 16 (f) mkd, and increased weight of testis and male pituitary (BMDLs of 0.5 and 0.6 mkd). The hypothyroxinemia correlated to a cluster of developmental parameters including delayed sexual development in females, decreased pup mortality, and effects on brainstem auditory evoked potentials Lilienthal, H., Verwer, C.M., Van der Ven, L.T.M., Piersma, A.H., Vos, J.G., 2008. Neurobehavioral effects of tetrabromobisphenol A (TBBPA) in rats after pre- and postnatal exposure. Toxicology. A second cluster of parameters in F1 animals was correlated to increased testis weight, and included female gonad weight, endometrium height, CYP19/aromatase activity in the ovary, and plasma testosterone levels in males. These two correlation clusters suggest a dual action of TBBPA. The only effects in the subacute study were decreased circulating T4 and increased T3 levels in males (BMDLs 48 and 124 mkd), and non-significant trends for these parameters in females, suggesting that the other effects in the reproduction study were induced during development. Combined with data of human exposure to environmental TBBPA, the margin of exposure for highly exposed populations can be calculated at 2.6, and current use of TBBPA may therefore be a matter of concern for human health.
A 28-day repeated dose study in rats (OECD407) enhanced for endocrine and immune parameters was performed with hexabromocyclododecane (HBCD). Rats were exposed by daily gavage to HBCD dissolved in ...corn oil in 8 dose groups with doses ranging between 0 and 200 mg/kg bw per day (mkd). Evaluation consisted of dose-response analysis with calculation of a benchmark dose at the lower 95% one-sided confidence bound (BMDL) at predefined critical effect sizes (CESs) of 10–20%. The most remarkable findings were dose-related effects on the thyroid hormone axis, that is, decreased total thyroxin (TT4, BMDL 55.5 mkd at CES − 10%), increased pituitary weight (29 mkd at 10%) and increased immunostaining of TSH in the pituitary, increased thyroid weight (1.6 mkd at 10%), and thyroid follicle cell activation. These effects were restricted to females. Female rats also showed increased absolute liver weights (22.9 mkd at 20%) and induction of T4-glucuronyl transferase (4.1 mkd at 10%), suggesting that aberrant metabolization of T4 triggers feedback activation of the thyroid hormone system. These effects were accompanied by possibly secondary effects, including increased cholesterol (7.4 mkd at 10%), increased tibial bone mineral density (> 49 mkd at 10%), both in females, and decreased splenocyte counts (0.3–6.3 mkd at 20%; only evaluated in males). Overall, female rats appeared to be more sensitive to HBCD than male rats, and an overall BMDL is proposed at 1.6 mkd, based on a 10% increase of the thyroid weight, which was the most sensitive parameter in the sequence of events.
The World Health Organization (WHO) recently updated the diagnostic criteria for serrated polyposis syndrome (SPS). One of the three previous diagnostic criteria (criterion II
2010
) is now abandoned
...: ≥ 1 serrated polyp (SP) proximal to the sigmoid in a first-degree relative (FDR) of a patient with SPS.
Individuals fulfilling this abandoned criterion now receive the same surveillance recommendations as all FDRs of patients with SPS. We aimed to compare the incidence of advanced neoplasia (AN) in FDRs with vs. without fulfillment of the abandoned criterion II
2010
. We retrospectively recruited FDRs of patients with SPS who underwent a colonoscopy, and stratified them according to fulfilment of criterion II
2010
at baseline. Our primary and secondary outcomes were AN incidence during surveillance and at baseline, respectively. We included 224 FDRs of patients with SPS, of whom 36 (16%) fulfilled criterion II
2010
at baseline. One hundred and five underwent surveillance after baseline. Criterion II
2010
-positive FDRs were at increased risk of AN, both during surveillance (hazard ratio 8.94, 95% CI 2.15–37.1, p = .003) as well as at baseline (adjusted odds-ratio 9.30, 95% CI 3.7–23.3, p < .001). FDRs of patients with SPS that underwent colonoscopy and fulfilled the abandoned criterion II
2010
for SPS diagnosis were at increased risk of AN at baseline and during surveillance in this small, retrospective cohort study. Our results should be interpreted with caution but suggest that adherence to surveillance recommendations for all FDRs of patients with SPS is important, especially for those that would have fulfilled the now abandoned criterion II
2010
.
Over the last decade the number of applications of fluorescence correlation spectroscopy (FCS) has grown rapidly. Here we describe the development and application of a software package, FCS Data ...Processor, to analyse the acquired correlation curves. The algorithms combine strong analytical power with flexibility in use. It is possible to generate initial guesses, link and constrain fit parameters to improve the accuracy and speed of analysis. A global analysis approach, which is most effective in analysing autocorrelation curves determined from fluorescence fluctuations of complex biophysical systems, can also be implemented. The software contains a library of frequently used models that can be easily extended to include user-defined models. The use of the software is illustrated by analysis of different experimental fluorescence fluctuation data sets obtained with Rhodamine Green in aqueous solution and enhanced green fluorescent protein in vitro and in vivo.
PDF
