8,237 research outputs found

    Ocean shrimp report 1979 season

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    Statewide Pacific ocean shrimp, Pandalus jordani, landings totaled 2,237.7 mt (4,922,857 lb), down 3,745 mt (8,240,386 lb) from the 1978 catch of 5,983.3 mt (13,163,243 lb). The 1979 landings are the lowest since 1976 when 1,545.5 mt (3,400,191 lb) were landed. Area A (Eureka-Crescent City)landings dropped to 1,842.5 mt (4,053,605 lb) from 5,046.3 mt (11,101,895 lb) landed during the previous season. No landings were made in Area B-1 (Fort Bragg). Only 2.0 mt (4,385 lb) were reported caught in Area B-2 (Bodega Bay). Record landings of 393.1 mt (864,867 lb) were made in Area C (Morro Bay-Avila), surpassing the previous record of 90.4 mt (199,000 lb) landed in 1953. In Area A a record 71 vessels, 34 double-rigged and 37 single-rigged, shrimped during the season. Average catch per hour was a low .15 mt (338 lb) and .22 mt (490 1b) for single-rig and double-rig vessels, respectively. In Area C average catch per hour was .23 mt (508 lb) and .42 mt (924 lb) for single-rig and double-rig vessels, respectively. Area A shrimp catches were dominated by 1-year-old shrimp throughout most of the season. The age composition in Area C shifted predominately from 2-year-old shrimp in May and June to predominately 1-year-old shrimp in July, August, October, and November. Area A was closed for one month from July 15 to August 15 because closure criteria of less than .16 mt (350 lb) per hour for two consecutive weeks was met and year class composition exceeded 70% of 1-year-old shrimp. The season was closed October 14 when the catch per hour criterion was exceeded again. (18pp.

    Inside out: Characterising Cybercrimes Committed Inside and Outside the Workplace

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    This comparison of cybercrime offenders within and outside the workplace reveals they display very different types of offending behaviour, involving different demographics, initiation pathways, and types of offence. The Cambridge Computer Crime Database (CCCD) is a database of open source information about cybercrime arrests and prosecutions in the United Kingdom. This study analyses data from the CCCD spanning nine years, from 1 January 2010 to 31 December 2018. Insiders are more likely to be older, and commit less-technical offences, primarily data and system breaches. They are less likely to offend with others, the offences are less likely to be international in nature, and they are less likely to receive a custodial sentence. Most alleged offenders are men, but women are more likely to offend within their occupation than outside the workplace. Of those that offend in the workplace, the largest group consists of police officers or police staff. This is likely to reflect differences in the type of organisations that pursue criminal action against insiders. We draw on a strain theory framework to argue that these findings accord with different kinds of strain and differing reactions to strain. The data for crimes outside the workplace support a `subcultural' pattern of adaptation to strain, with offenders tending to be younger, male and linked to co-offenders. The findings relating to insiders support an opportunity model of crime, with inter-workplace variation in opportunities, working cultures and sources of strain present in different workplaces.This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) [grant EP/M020320/1]

    WASP-1: A lithium- and metal-rich star with an oversized planet

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    In this paper we present our results of a comprehensive spectroscopicanalysis of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/- 45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high abundance of lithium, log n(Li) = 2.91 +/- 0.05. These parameters suggests an age for the system of 1-3 Gyr and a stellar mass of 1.25-1.35 M_sun. This means that WASP-1 has properties very similar to those of HD 149026, the host star for the highest density planet yet detected. Moreover, their planets orbit at comparable distances and receive comparable irradiating fluxes from their host stars. However, despite the similarity of WASP-1 with HD 149026, their planets have strongly different densities. This suggests that gas-giant planet density is not a simple function of host-star metallicity or of radiation environment at ages of ~2 Gyr.Comment: Accepted for publication in MNRAS. 6 pages, 4 figure

    Modelling substorm chorus events in terms of dispersive azimuthal drift

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    The Substorm Chorus Event (SCE) is a radio phenomenon observed on the ground after the onset of the substorm expansion phase. It consists of a band of VLF chorus with rising upper and lower cutoff frequencies. These emissions are thought to result from Doppler-shifted cyclotron resonance between whistler mode waves and energetic electrons which drift into a ground station's field of view from an injection site around midnight. The increasing frequency of the emission envelope has been attributed to the combined effects of energy dispersion due to gradient and curvature drifts, and the modification of resonance conditions and variation of the half-gyrofrequency cutoff resulting from the radial component of the <i><b>E</b></i>x<i><b>B</b></i> drift. </p><p style="line-height: 20px;"> A model is presented which accounts for the observed features of the SCE in terms of the growth rate of whistler mode waves due to anisotropy in the electron distribution. This model provides an explanation for the increasing frequency of the SCE lower cutoff, as well as reproducing the general frequency-time signature of the event. In addition, the results place some restrictions on the injected particle source distribution which might lead to a SCE.<Br><Br> <b>Key words. </b>Space plasma physics (Wave-particle interaction) – Magnetospheric physics (Plasma waves and instabilities; Storms and substorms

    From playing games to committing crimes: A multi-technique approach to predicting key actors on an online gaming forum

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    We propose a systematic framework for analysing forum datasets, which contain minimal structure, and are non-trivial to analyse at scale, aiming to support future analysis of underground forum communities. We use a multi-technique approach which draws on a combination of features, including post classifications extracted using natural language processing tools, and apply clustering and predictive techniques to this dataset, to predict potential key actors---individuals who have a central role in overtly criminal activities, or activities which could lead to later offending, and hence might benefit most from interventions. We predict 49 key actors on an underground gaming-specific cheating and hacking forum, validated by observing only overlaps of techniques, combined with topic analysis, to build a classifier for key actor status. In addition, we also use these techniques to provide further insight of key actor activity. We found one cluster and two posting trajectories to contain a high proportion of key actors, logistic regression found an actor's h-index to have higher odds for prediction than other features, and partial dependence plots found reputation to have a significant change in prediction between values of 100 to 1000

    Surface differential rotation and prominences of the Lupus post T Tauri star RX J1508.6-4423

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    We present in this paper a spectroscopic monitoring of the Lupus post T Tauri star RX J1508.6-4423 carried out at two closely separated epochs (1998 May 06 and 10) with the UCL Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope. Applying least-squares convolution and maximum entropy image reconstruction techniques to our sets of spectra, we demonstrate that this star features on its surface a large cool polar cap with several appendages extending to lower latitudes, as well as one spot close to the equator. The images reconstructed at both epochs are in good overall agreement, except for a photospheric shear that we interpret in terms of latitudinal differential rotation. Given the spot distribution at the epoch of our observations, differential rotation could only be investigated between latitudes 15° and 60°. We find in particular that the observed differential rotation is compatible with a solar-like law (i.e., with rotation rate decreasing towards high latitudes proportionally to sin 2l, where l denotes the latitude) in this particular latitude range. Assuming that such a law can be extrapolated to all latitudes, we find that the equator of RX J1508.6-4423 does one more rotational cycle than the pole every 50 ±10 d, implying a photospheric shear 2 to 3 times stronger than that of the Sun. We also discover that the Hα emission profile of RX J1508.6-4423 is most of the time double-peaked and strongly modulated with the rotation period of the star. We interpret this rotationally modulated emission as being caused by a dense and complex prominence system, the circumstellar distribution of which is obtained through maximum entropy Doppler tomography. These maps show in particular that prominences form a complete and inhomogeneous ring around the star, precisely at the corotation radius. We use the total Hα and Hβ emission flux to estimate that the mass of the whole prominence system is about 10 20g. From our observation that the whole cloud system surrounding the star is regenerated in less than 4 d, we conclude that the braking time-scale of RX J1508.6-4423 is shorter than 1 Gyr, and that prominence expulsion is thus likely to contribute significantly to the rotational spindown of young low-mass stars

    The Angular Momentum Evolution of Very Low Mass Stars

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    We present theoretical models of the angular momentum evolution of very low mass stars (0.1 - 0.5 M_sun) and solar analogues (0.6 - 1.1 M_sun). We investigate the effect of rotation on the effective temperature and luminosity of these stars. We find that the decrease in T_eff and L can be significant at the higher end of our mass range, but becomes negligible below 0.4 M_sun. Formulae for relating T_eff to mass and v_rot are presented. We compare our models to rotational data from young open clusters of different ages to infer the rotational history of low mass stars, and the dependence of initial conditions and rotational evolution on mass. We find that the qualitative conclusions for stars below 0.6 M_sun do not depend on the assumptions about internal angular momentum transport, which makes these low mass stars ideal candidates for the study of the angular momentum loss law and distribution of initial conditions. We find that neither models with solid body nor differential rotation can simultaneously reproduce the observed stellar spin down in the 0.6 to 1.1 M_sun mass range and for stars between 0.1 and 0.6 M_sun. The most likely explanation is that the saturation threshold drops more steeply at low masses than would be predicted with a simple Rossby scaling. In young clusters there is a systematic increase in the mean rotation rate with decreased temperature below 3500 K (0.4 M_sun). This suggests either inefficient angular momentum loss or mass-dependent initial conditions for stars near the fully convective boundary. (abridged)Comment: To appear in the May 10, 2000 Ap

    The first WASP public data release

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    The WASP (wide angle search for planets) project is an exoplanet transit survey that has been automatically taking wide field images since 2004. Two instruments, one in La Palma and the other in South Africa, continually monitor the night sky, building up light curves of millions of unique objects. These light curves are used to search for the characteristics of exoplanetary transits. This first public data release (DR1) of the WASP archive makes available all the light curve data and images from 2004 up to 2008 in both the Northern and Southern hemispheres. A web interface () to the data allows easy access over the Internet. The data set contains 3 631 972 raw images and 17 970 937 light curves. In total the light curves have 119 930 299 362 data points available between them

    Issues in the reporting of epidemiological studies: a survey of recent practice.

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    OBJECTIVES: To review current practice in the analysis and reporting of epidemiological research and to identify limitations. DESIGN: Examination of articles published in January 2001 that investigated associations between risk factors/exposure variables and disease events/measures in individuals. SETTING: Eligible English language journals including all major epidemiological journals, all major general medical journals, and the two leading journals in cardiovascular disease and cancer. MAIN OUTCOME MEASURE: Each article was evaluated with a standard proforma. RESULTS: We found 73 articles in observational epidemiology; most were either cohort or case-control studies. Most studies looked at cancer and cardiovascular disease, even after we excluded specialty journals. Quantitative exposure variables predominated, which were mostly analysed as ordered categories but with little consistency or explanation regarding choice of categories. Sample selection, participant refusal, and data quality received insufficient attention in many articles. Statistical analyses commonly used odds ratios (38 articles) and hazard/rate ratios (23), with some inconsistent use of terminology. Confidence intervals were reported in most studies (68), though use of P values was less common (38). Few articles explained their choice of confounding variables; many performed subgroup analyses claiming an effect modifier, though interaction tests were rare. Several investigated multiple associations between exposure and outcome, increasing the likelihood of false positive claims. There was evidence of publication bias. CONCLUSIONS: This survey raises concerns regarding inadequacies in the analysis and reporting of epidemiological publications in mainstream journals

    Ocean shrimp report 1980 season

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    Statewide Pacific ocean shrimp, Pandalus jordani, landings totaled 2,033.1 mt (4,472,749 lb) down 204.6 mt (450,108 lb) from the 1979 catch of 2,237.7 m t (4,922,857 lb). The 1980 landings are the lowest since 1976 when 1,545.5 mt (3,400,191 lb) were landed. Area A (Eureka-Crescent City) landings dropped to 1,234 mt (2,716,147 lb) from 1,842.5 mt (4,053,605 lb) landed during the previous season. Area B-1 (Fort Bragg) landings totaled 79.3 mt (174,395 lb) from catches made during the last 9 days of the season. Only 100 lb were reported caught in Area B-2 (Bodega Bay). Record landings of 719.1 mt (1,582,107 lb were made in Area C (Morro Bay-Avila), surpassing the previous record of 391 mt (864,667 lb) landed in 1979. In Area A a record 80 vessels, 34 double-rigged and 46 single-rigged, made shrimp deliveries during the season. Average catch per hour was a very low .ll mt (234 lb) and .20 mt (446 lb) for single- rig and double-rig vessels, respectively. In Area C average catch per hour was .25 mt (557 lb) and .21 mt (462 lb) for single-rig and double-rig vessels, respectively. Area A shrimp catches were dominated by 1-year-old shrimp in percent by number throughout the season. The age composition in Area C shifted from predominately 2-year-old shrimp in April, May, and June to predominately 1-year-old shrimp for the remainder of the season. Area A was closed for one month from June 1 to July 1 because closure criteria of less than .16 mt (350 lb) per hour for two consecutive weeks was met and year class composition exceeded 70% of year-old shrimp. The season was closed for the year on August 25 when the catch per hour and percent 1-year-old shrimp criteria was exceeded again. (22pp.
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