Effects of temperature on the biology of the northern shrimp, Pandalus borealis, in the Gulf of Maine

Length-frequency data collected from inshore and offshore locations in the Gulf of Maine in 1966-1968 indicated that ovigerous female northern shrimp (Pandalus borealis) first appeared offshore in August and September and migrated inshore in the fall and winter. Once eggs hatched, surviving females returned offshore. Juveniles and males migrated offshore during their first two years of life. Sex transition occurred in both inshore and oll'shore waters, but most males changed sex offshore during their third and fourth years. Most shrimp changed sex and matured as females for the first time in their fourth year. Smaller females and females exposed to colder bottom temperatures spawned first. The incidence of egg parasitism peaked in January and was higher for shrimp exposed to warmer bottom temperatures. Accelerated growth at higher temperatures appeared to result in earlier or more rapid sex transition. Males and non-ovigerous females were observed to make diurnal vertical migrations, but were not found in near- surface waters where the temperature exceeded 6°C. Ovigerous females fed more heavily on benthic molluscs in inshore waters in the winter, presumably because the egg masses they were carrying prevented them from migrating vertically at night. Northern shrimp were more abundant in the southwestern region of the Gulf of Maine where bottom temperatures remain low throughout the year. Bottom trawl catch rates were highest in Jeffreys Basin where bottom temperatures were lower than at any other sampling location. Catch rates throughout the study area were inversely related to bottom temperature and reached a maximum at 3°C. An increase of 40% in fecundity between 1973 and 1979 was associated with a decline of 2-3°C in April-July offshore bottom temperatures. Furthermore, a decrease in mean fecundity per 25 mm female between 1965 and 1970 was linearly related to reduced landings between 1969 and 1974. It is hypothesized that temperature-induced changes in fecundity and, possibly, in the extent of egg mortality due to parasitism, may provide a mechanism which could partially account for changes in the size of the Gulf of Maine northern shrimp population during the last thirty years. (PDF file contains 28 pages.

Aircraft control system

An aircraft control system is described which is particularly suited to rotary wing aircraft. Longitudinal acceleration and course rate commands are derived from a manual control stick to control translational velocity of the aircraft along a flight path. In the collective channel the manual controls provide vertical velocity commands. In the yaw channel the manual controls provide sideslip or heading rate commands at high or low airspeeds, respectively. The control system permits pilots to fly along prescribed flight paths in a precise manner with relatively low work load

Investigation using data from ERTS-1 to develop and implement utilization of living marine resources

The author has identified the following significant results. This 15-month ERTS-1 investigation produced correlations between satellite, aircraft, menhaden fisheries, and environmental sea truth data from the Mississippi Sound. Selected oceanographic, meteorological, and biological parameters were used as indirect indicators of the menhaden resource. Synoptic and near real time sea truth, fishery, satellite imagery, aircraft acquired multispectral, photo and thermal IR information were acquired as data inputs. Computer programs were developed to manipulate these data according to user requirements. Preliminary results indicate a correlation between backscattered light with chlorophyll concentration and water transparency in turbid waters. Eight empirical menhaden distribution models were constructed from combinations of four fisheries-significant oceanographic parameters: water depth, transparency, color, and surface salinity. The models demonstrated their potential for management utilization in areas of resource assessment, prediction, and monitoring

Fixed-base simulation evaluation of various low-visibility landing systems for helicopters

Fixed base simulation evaluation of one fully automatic and six manual low visibility landing systems for helicopter

Circulation policies for external users: A comparative study of public urban research institutions

This article is a study of the policies that govern the use of the university library by external users at Indiana University–Purdue University Indianapolis (IUPUI) and 12 peer institutions used by IUPUI for comparative purposes. A search of each institution’s Web site was conducted as well as interviews with circulation librarians and managers. Although it was useful to learn of common practices, it was especially beneficial to learn about policies that differed substantially from those in place at comparable institutions. Creative solutions developed to address problems at other libraries can be used to influence policy development

The economic value of remote sensing by satellite: An ERTS overview and the value of continuity of service. Volume 2: Source document

The economic value of an ERS system with a technical capability similar to ERTS, allowing for increased coverage obtained through the use of multiple active satellites in orbit is presented. A detailed breakdown of the benefits achievable from an ERS system is given and a methodology for their estimation is established. The ECON case studies in agriculture, water use, and land cover are described along with the current ERTS system. The cost for a projected ERS system is given

Project for the analysis of technology transfer Quarterly report, 1 Apr. 1969 - 30 Jun. 1969

Patterns, statistical analyses, and case studies of transfer and utilization of NASA generated technolog

The effect of a temporary absence of target velocity information on visual tracking

Experiments with the Rashbass ‘step-ramp’ paradigm have revealed that the initial catchup saccade that occurs near pursuit onset uses target velocity as well as position information in its programming. Information about both position and motion also influences smooth pursuit. To investigate the timing of velocity sampling near the initiation of saccades and smooth pursuit, we analyzed the eye movements made in nine ‘step-ramp’ conditions, produced by combining –2, 0 and +2 deg steps with –8, 0 and +8 deg/s ramps. Each trial had either no temporal gap or a 50-ms gap during which the laser target was extinguished, beginning 25, 50, 75 or 100 ms after the step. Six subjects repeated each of the resulting 45 conditions 25 times. With no temporal gap, saccades were larger in the step-ramp-away’ than the ‘step-only’ condition, confirming that saccade programming incorporates ramp velocity information. A temporal gap had no effect on the accuracy of saccades on ‘step-only’ trials, but often caused undershoots in ‘step-ramp’ trials. A 50-ms gap within the first 100 ms also increased the latency of the initial saccade. Although initial pursuit velocity was unaffected by a temporal gap, a gap that started at 25 ms reliably delayed pursuit onset for ramp motion of the target toward the fovea. Later gaps had a minimal effect on initial pursuit latency. The similar timing of the temporal gaps in target motion information that affect the initiation of saccades and pursuit provides further behavioral evidence that the two types of eye movements share pre-motor neural mechanisms

Burgess v. State, 313 So. 2d 479 (Fla. 2d Dist. Ct. App. 1975), cert. denied, 326 So. 2d 441 (Fla. 1976)

Criminal Law- ARREST- COURT UPHOLDS THE RIGHT TO RESIST AN UNLAWFUL ARREST, BUT ISSUE SHOULD BE REVISITED UNDER NEW STATUTE