Rekefisket som naturhistorie og samfundssak

1. Trawl fishing for deep sea prawns commenced in Norway in the autumn of 1898 after Hjort had proved in 1897 the existence of great quantities of P. borealis in the fjords of East Norway. On the recommendation of Dr. C. G. JOHS. PETERSEN, HJORT constructed a serviceable gear for this fishery by modifying the Danish eel-seine to an otter-trawl. In table 1 and Figures 2, 3 and 4 a summary is given of the growth of prawn fishing in Norway, Sweden and Denmark. In 1935 nearly 5 million kilogrammes of prawns were fished by these three countries altogether, and 2/3 of this quantity by Norway alone. 2. On the basis of information and charts placed at our disposal, mainly by two fishermen, a survey is given of the prawning grounds which are known from the Svenör Bank to the Trondheim Fjord. 3. The development of gear and fishing craft from HJORT's first trawl and sailing boats to modern gear and motor vessels is described. 4. The statistical value of the prawn fishing in the case of Norway has amounted in recent years to about 2 million kroner per annum. From 1908 to 1935 the value of the total yield in the case of Norway has been more than 22,5 million kroner. The incomes of the fishermen vary considerably according to their ability. Some examples show that in good years the gross income has amounted to about Kr. 20.000,00. The nett income amounts to 35 % - 50 % of the gross. 5. The life history of P. borealis is described on the basis of previous investigations and those undertaken by us. An account is given of the growth of the prawn in Norwegian waters and of the probable number of moultings to which it is subjected. 6. When the prawn fishery commenced an accumulated stock was fished. After the lapse of a number of years the catches became dependent on the annual renewals and the intensity of the fishery. The yield has therefore declined considerably on all the old grounds until in recent years it has become more constant with minor fluctuations. 7. The possibility of discovering new prawn grounds in the Norwegian Channel has been investigated by cruises from the Reef off Kristiansand S. to the waters off Stadt during the summer of 1934. On these cruises it was found that the quantity of prawns declined gradually with the disappearance of detritus from the material of the sea-bed. From Utsira and northwards the bottom consisted of pure sand. 8. Similar experience was gained by BIGELOW and HJORT in the Gulf of Maine (U.S.A.) during the summer of 1936. Quantities of P. borealis capable of being fished on an industrial scale were found in waters which had strong points of resemblance with the prawn grounds in the Norwegian fjords. 9. A comparison between the animal life of the prawn grouncls examined by bottom sampler (BROCH 1935) and that brought up by the trawl shows that the trawl only takes up a very small selection of the bottom fauna, namely, the large forms which live on and over the bottom. A list of the species of fish caught by trawl in Norwegian waters is also given here, and the quantities in which they are takeil. 10. The injurious effects which trawling is said to have on other fisheries are discussed. 11. The effect of the gear on the size of the stock of prawns is examined. 12. The bearing of our investigation is discussed, and recommendations for a minimum mesh in the trawl are made in order to bring the fishery into rational forms and to increase the catches of the fishermen

Rekefisket som naturhistorie og samfundssak

1. Trawl fishing for deep sea prawns commenced in Norway in the autumn of 1898 after Hjort had proved in 1897 the existence of great quantities of P. borealis in the fjords of East Norway. On the recommendation of Dr. C. G. JOHS. PETERSEN, HJORT constructed a serviceable gear for this fishery by modifying the Danish eel-seine to an otter-trawl. In table 1 and Figures 2, 3 and 4 a summary is given of the growth of prawn fishing in Norway, Sweden and Denmark. In 1935 nearly 5 million kilogrammes of prawns were fished by these three countries altogether, and 2/3 of this quantity by Norway alone. 2. On the basis of information and charts placed at our disposal, mainly by two fishermen, a survey is given of the prawning grounds which are known from the Svenör Bank to the Trondheim Fjord. 3. The development of gear and fishing craft from HJORT's first trawl and sailing boats to modern gear and motor vessels is described. 4. The statistical value of the prawn fishing in the case of Norway has amounted in recent years to about 2 million kroner per annum. From 1908 to 1935 the value of the total yield in the case of Norway has been more than 22,5 million kroner. The incomes of the fishermen vary considerably according to their ability. Some examples show that in good years the gross income has amounted to about Kr. 20.000,00. The nett income amounts to 35 % - 50 % of the gross. 5. The life history of P. borealis is described on the basis of previous investigations and those undertaken by us. An account is given of the growth of the prawn in Norwegian waters and of the probable number of moultings to which it is subjected. 6. When the prawn fishery commenced an accumulated stock was fished. After the lapse of a number of years the catches became dependent on the annual renewals and the intensity of the fishery. The yield has therefore declined considerably on all the old grounds until in recent years it has become more constant with minor fluctuations. 7. The possibility of discovering new prawn grounds in the Norwegian Channel has been investigated by cruises from the Reef off Kristiansand S. to the waters off Stadt during the summer of 1934. On these cruises it was found that the quantity of prawns declined gradually with the disappearance of detritus from the material of the sea-bed. From Utsira and northwards the bottom consisted of pure sand. 8. Similar experience was gained by BIGELOW and HJORT in the Gulf of Maine (U.S.A.) during the summer of 1936. Quantities of P. borealis capable of being fished on an industrial scale were found in waters which had strong points of resemblance with the prawn grounds in the Norwegian fjords. 9. A comparison between the animal life of the prawn grouncls examined by bottom sampler (BROCH 1935) and that brought up by the trawl shows that the trawl only takes up a very small selection of the bottom fauna, namely, the large forms which live on and over the bottom. A list of the species of fish caught by trawl in Norwegian waters is also given here, and the quantities in which they are takeil. 10. The injurious effects which trawling is said to have on other fisheries are discussed. 11. The effect of the gear on the size of the stock of prawns is examined. 12. The bearing of our investigation is discussed, and recommendations for a minimum mesh in the trawl are made in order to bring the fishery into rational forms and to increase the catches of the fishermen

Geometrical structure effect on localization length of carbon nanotubes

The localization length and density of states of carbon nanotubes are evaluated within the tight-binding approximation. By comparison with the corresponding results for the square lattice tubes, it is found that the hexagonal structure affects strongly the behaviors of the density of states and localization lengths of carbon nanotubes.Comment: 7 pages, 4 figures, revised version to appear in Chin. Phys. Lett. The title is changed. Some arguments are adde

Environmental Controls of InSAR-Based Periglacial Ground Dynamics in a Sub-Arctic Landscape

Periglacial environments are characterized by highly dynamic landscapes. Freezing and thawing lead to ground movement, associated with cryoturbation and solifluction. These processes are sensitive to climate change and variably distributed depending on multiple environmental factors. In this study, we used multi-geometry Sentinel-1 Synthetic Aperture Radar Interferometry (InSAR) to investigate the spatial distribution of the mean annual ground velocity in a mountainous landscape in Northern Norway. Statistical modeling was employed to examine how periglacial ground velocity is related to environmental variables characterizing the diverse climatic, geomorphic, hydrological and biological conditions within a 148 km(2) study area. Two-dimensional (2D) InSAR results document mean annual ground velocity up to 15 mm/yr. Vertical and horizontal velocity components in the East-West plane show variable spatial distribution, which can be explained by the characteristics of cryoturbation and solifluction operating differently over flat and sloping terrain. Statistical modeling shows that slope angle and mean annual air temperature variables are the most important environmental factors explaining the distribution of the horizontal and vertical components, respectively. Vegetation and snow cover also have a local influence, interpreted as indicators of the ground material and moisture conditions. The results show contrasted model performance depending on the velocity component used as a response variable. In general, our study highlights the potential of integrating radar remote sensing and statistical modeling to investigate mountainous regions and better understand the relations between environmental factors, periglacial processes and ground dynamics.Peer reviewe

A Polya Tree Based Model for Unmarked Individuals in an Open Wildlife Population

Many ecological sampling schemes do not allow for unique marking of individuals. Instead, only counts of individuals detected on each sampling occasion are available. In this paper, we propose a novel approach for modelling count data in an open population where individuals can arrive and depart from the site during the sampling period. A Bayesian nonparametric prior, known as Polya Tree, is used for modelling the bivariate density of arrival and departure times. Thanks to this choice, we can easily incorporate prior information on arrival and departure density while still allowing the model to flexibly adjust the posterior inference according to the observed data. Moreover, the model provides great scalability as the complexity does not depend on the population size but just on the number of sampling occasions, making it particularly suitable for data-sets with high numbers of detections. We apply the new model to count data of newts collected by the Durrell Institute of Conservation and Ecology, University of Kent

Patient safety culture lives in departments and wards: Multilevel partitioning of variance in patient safety culture

<p>Abstract</p> <p>Background</p> <p>Aim of study was to document 1) that patient safety culture scores vary considerably by hospital department and ward, and 2) that much of the variation is across the lowest level organizational units: the wards. Setting of study: 500-bed Norwegian university hospital, September-December 2006.</p> <p>Methods</p> <p>Data collected from 1400 staff by (the Norwegian version of) the generic version of the Safety Attitudes Questionnaire (SAQ Short Form 2006). Multilevel analysis by MLwiN version 1.10.</p> <p>Results</p> <p>Considerable parts of the score variations were at the ward and department levels. More organization level variation was seen at the ward level than at the department level.</p> <p>Conclusions</p> <p>Patient safety culture improvement efforts should not be limited to all-hospital interventions or interventions aimed at entire departments, but include involvement at the ward level, selectively aimed at low-scoring wards. Patient safety culture should be studied as closely to the patient as possible. There may be such a thing as "hospital safety culture" and the variance across hospital departments indicates the existence of department safety cultures. However, neglecting the study of patient safety culture at the ward level will mask important local variations. Safety culture research and improvement should not stop at the lowest formal level of the hospital (wards, out-patient clinics, ERs), but proceed to collect and analyze data on the micro-units within them.</p

The BATSE-Swift luminosity and redshift distributions of short-duration GRBs

We compare the luminosity function and rate inferred from the BATSE short hard bursts (SHBs) peak flux distribution with the redshift and luminosity distributions of SHBs observed by Swift/HETE II. While the Swift/HETE II SHB sample is incompatible with SHB population that follows the star formation rate, it is compatible with a SHB rate that reflect a distribution of delay times after the SFR. This would be the case if SHBs are associated with binary neutron star mergers. The available data allows, however, different interpretations. For example, a population whose rate is independent of the redshift fits the data very well. The implied SHB rates that we find range from $\sim 8$ to $\sim 30h_{70}^3$Gpc$^{-3}$yr$^{-1}$. This is a much higher rate than what was previously estimated. A detailed (2 dimensional) look at the best fit models shows, however, some discrepancy between the four Swift/HETE II SHBs and the models based on BATSE SHBs. This could be a statistical fluke. It could also arise from wrong estimates of the triggering criteria or from selection effects. If real it may indicate the existence of two SHB populations with different luminosity functions and redshift distributions.Comment: Revised version includes additional bursts and revised redshift of older burst