13,663 research outputs found

    Pacific herring, Clupea harengus pallasi, studies in San Francisco and Tomales Bays, April 1987 to March 1988

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    Herring schools were surveyed hydroacoustically and sampled in San Francisco Bay from late October 1987 to March 1988. Nine large schools (greater than 1000 tons) and four smaller ones were detected. Total acoustic biomass estimate, using a combination of echo integration and "visual integration" methods, was 71,110 tons. Improved acoustic calibration parameters resulted in this estimate being close to the spawn escapement-plus-catch estimate of 68,881 tons. However, the two biomass survey methods ere complementary and, when used together, provide a more accurate estimate of the spawning population than either method alone. Eighty-two samples, containing a total of 16,316 herring, were collected with variable-mesh gill net, midwater trawl, or obtained from the roundhaul fishery. Mean body length decreased by more then 20 mm from the beginning to the end of the spawning season. Sex ratios favored males in November and December, while females were more abundant in February and March. The 1982 through 1986 year classes (6- through 2-yr olds) contributed approximately 98% by weight and number to the total 1987-88 spawning biomass in San Francisco Bay. Herring year classes aged 7 and older each comprised no more then 1% of any school. Above average recruitment occurred for the 1986 year class. Recruitment may not be complete for some year classes until age 3 yr. This was particularly evident for the 1985 year clear. (72pp.

    Pacific herring, Clupea harengus pallasi, studies in San Francisco Bay, Monterey Bay, and the Gulf of the Farallones, July 1982 to March 1983

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    Herring stocks were hydroacoustically surveyed and sampled in San Francisco Bay from November 1982 to March 1983. Twelve discrete herring schools were identified, all of which spawned between November 7 and February 23. One additional school was found in the Bay in March but showed no evidence of spawning. Total biomass estimate from hydroacoustic surveys was 67,040 tons. Based on MRR biomass estimates from spawned egg counts, an additional 10,000 tons may have spawned in November and December without being detected hydroacoustically. The largest schools occurred in January and February. Hydroacoustic estimates of biomass for individual schools during the season ranged from 270 to 22,300 tons. Sixty-seven samples, containing a total of 12,232 herring, were collected with variable mesh gill net and midwater trawl or obtained from the commercial roundhaul and gill net fisheries. In general, a trend was observed of decreasing mean size and age as the season progressed. Schools spawning in November and December consisted primarily of 4-, 5-, 6-, and 7-yr-old fish. Schools sampled from January to March were predominantly 2-, 3-, 4-, and 5-yr-old herring. The 1978, 1979, and 1980 yr classes (ages 5, 4, and 3 yr) were strong, comprising up to 90% of the samples. The 1981 yr class (2-yr olds) was relatively weak. Abundant rainfall and resultant low salinity in San Francisco Bay surface waters apparently delayed or prevented herring from spawning in February and March. A relationship may exist between relative abundance of young-of-the-year fish, as noted from midwater trawl samples collected by the Department's Bay-Delta Study, and the resultant year class strength of newly recruited 2-yr-old herring in San Francisco Bay's spawning stocks. (57pp.

    Pacific herring, Clupea harengus pallasi, studies in San Francisco Bay, April 1986 to March 1987

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    Herring schools were surveyed hydroacoustically and sampled in San Francisco Bay from late October 1986 to March 1987. Eight large schools (greater than 1000 tons each) spawned from December to February and seven smaller schools were detected throughout the spawning season. Total acoustic biomass estimate using a "visual integration" technique was 40,930 tons, and it was determined from spawn escapement and commercial landings that an additional 2240 tons were not detected. This is a slight increase from last season's total of approximately 42,200 tons. For the first time, biomass was also estimated using echo integration equipment. A total biomass was obtained of 33,050 tons, including herring not detected acoustically. This estimate must be considered preliminary and subject to revision after target strength of San Francisco Bay herring is determined. Eighty-seven samples, containing a total of 13,125 herring, were collected with variable-mesh gill net and midwater trawl or obtained from the roundhaul and gill net fisheries. Mean body length (BL) of sampled herring decreased by about 20 mm from the beginning to the end of the spawning season. A combination of variable-mesh gill net and midwater trawl samples for a particular school closely approximates mean BL and age composition data from unbiased roundhaul samples. Age-weight and age-length relationships were average to above average compared with those of the previous two seasons. The 1982 year class exhibited unusually good growth, with a mean BL of 202.8 mm for herring aged from stratified random samples. The 1982 through 1985 year classes (5- through 2-yr olds) contributed 97% by number and 95% by weight to the total 1986-87 spawning biomass in San Francisco Bay. Good recruitment has occurred during the past four seasons. The weak 1981 year class contributed little to the total biomass as 6-yr olds. Average catch per tow of young-of-the-year (YOY) herring is a potential index of abundance for recruitment 18 months later as 2-yr olds. Estimated recruitment has only varied by 15% during the past three seasons and does not reflect the magnitude or trend in YOY catches in the bay. (85pp.

    Pacific herring, Clupea harengus pallasi, experimental roe-on-kelp open pound fishery studies in San Francisco Bay, December 1987 to February 1988

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    The experimental open pound herring roe-on-kelp (ROK) fishery was studied in San Francisco Bay from mid December 1987 to mid February 1988. Five different harvests were observed and sampled. A total of 19.7 tons of Macrocystis sp. kelp covered with herring eggs was processed during this period. Kelp harvested from the Santa Barbara Channel Islands was transported to San Francisco Bay for hanging on the pounds. Weather conditions at the channel islands affected the condition and dimensions of the harvested kelp. Once suspended on the pounds in bay waters, the cut kelp deteriorated in 8 to 10 d. Based on our sampling, an average of 0.98 tons of kelp with a total blade surface area of 3031 m2 was suspended from each pound. ROK was sampled at the shoreside processing facility. Densities of attached eggs ranged from light (less than three layers) to heavy (more than six layers) for the five different spawns. Egg coverage on each pound also varied; kelp towards the middle portion of the pound received heavier deposition of eggs. Average weight increase from egg deposition, per blade, was 780% with the kelp weighing an average of 12.2% of the total. An average 13.2% by weight was trimmed during processing. A multiplication factor of 0.206 should be used to convert individual roe herring allotments to ROK allotments. Standard plastic totes containing processed ROK averaged 1783 lb total gross weight. Totes contained an average of 49.7% ROK by weight. Samples of roe-on-kelp increased an average of 10.9% in weight after brining during processing. (35pp.

    Religion and belief in Higher Education: the experiences of staff and students

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    This report presents key evidence from ‘Religion and belief in higher education: researching the experiences of staff and students’, a research project commissioned by ECU. The research methods used for this project took into consideration institutional contexts and backgrounds to religion or belief issues to ensure sensitivity to the issues involved. The project utilised the experience of the project stakeholder group in designing all research approaches.Equality Challenge Uni

    Waterfowl Harvest and Hunter Use at Carlyle Lake During the 1973 Season

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    Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 7Report issued on: April 15, 197

    Participant satisfaction with Youth Justice Conferencing

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    Aims: To evaluate offender and victim satisfaction with New South Wales (NSW) Youth Justice Conferences (YJCs) immediately after conference participation and to re-assess victim satisfaction 4 months after the conference date.Method: A self-report survey designed to assess satisfaction with YJCs was completed by 263 offenders and 141 victims immediately following their participation in a NSW YJC. Additionally, 96 victims also participated in a phone-based survey 4 months after the conference.Results: When asked immediately following the conference, more than 85 per cent of offenders and victims reported being ‘satisfied’ or ‘very satisfied’ with most aspects of the conference. High levels of satisfaction with conferencing were also reported by victims 4 months after the conference. For some measures, however, the percentage of victims who were ‘satisfied’ or ‘very satisfied’ was not as high at the 4-month follow-up, as it was in the baseline survey. The aspect of conferencing that victims at the 4-month follow-up reported the least satisfaction with was the lack of feedback they received from conference staff about the offender’s completion of the outcome plan. Fewer than half of the victims were ‘satisfied’ or ‘very satisfied’ with this part of the conference.Conclusion: The results of this study suggest that offender and victim satisfaction is high immediately following a YJC. Even 4 months after a YJC, victim satisfaction with most aspects of conferencing remains high. Satisfaction levels may be increased still further if, at some point prior to the end of the statutory time-period for completing the plan, victims were provided with feedback about the offender’s progress towards completing the outcome plan. Further research also needs to be conducted comparing victim satisfaction following a conference with victim satisfaction following a court appearance

    Sense of agency, associative learning, and schizotypy

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    Despite the fact that the role of learning is recognised in empirical and theoretical work on sense of agency (SoA), the nature of this learning has, rather surprisingly, received little attention. In the present study we consider the contribution of associative mechanisms to SoA. SoA can be measured quantitatively as a temporal linkage between voluntary actions and their external effects. Using an outcome blocking procedure, it was shown that training action-outcome associations under conditions of increased surprise augmented this temporal linkage. Moreover, these effects of surprise were correlated with schizotypy scores, suggesting that individual differences in higher level experiences are related to associative learning and to its impact on SoA. These results are discussed in terms of models of SoA, and our understanding of disrupted SoA in certain disorders

    Attribution of intentional causation influences the perception of observed movements: behavioral evidence and neural correlates

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    Recent research on human agency suggests that intentional causation is associated with a subjective compression in the temporal interval between actions and their effects. That is, intentional movements and their causal effects are perceived as closer together in time than equivalent unintentional movements and their causal effects. This so-called intentional binding effect is consistently found for one's own self-generated actions. It has also been suggested that intentional binding occurs when observing intentional movements of others. However, this evidence is undermined by limitations of the paradigm used. In the current study we aimed to overcome these limitations using a more rigorous design in combination with functional Magnetic Resonance Imaging (fMRI) to explore the neural underpinnings of intentional binding of observed movements. In particular, we aimed to identify brain areas sensitive to the interaction between intentionality and causality attributed to the observed action. Our behavioral results confirmed the occurrence of intentional binding for observed movements using this more rigorous paradigm. Our fMRI results highlighted a collection of brain regions whose activity was sensitive to the interaction between intentionality and causation. Intriguingly, these brain regions have previously been implicated in the sense of agency over one's own movements. We discuss the implications of these results for intentional binding specifically, and the sense of agency more generally
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