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It is well established that excitability of the primary motor cortex increases during action observation. However, the modulation of motor cortex excitability during observation of different actions, with distinct movement patterns, is not fully understood. The aim of the current study was to examine time-dependent changes in corticospinal excitability during observation of two actions with different levels of complexity. We developed videos of two distinct actions (a point and a reach-and-grasp), that were matched in video length, action onset, and onset of kinematics. Single-pulse transcranial magnetic stimulation was used to investigate time-dependent changes in primary motor cortex excitability during observation of the two actions. Motor evoked potentials (MEP) were recorded from two intrinsic hand muscles, namely first dorsal interosseous (FDI) and abductor digiti minimi. Results showed no difference in MEP amplitude during observation of a static hand compared to observation of the actions. When comparing the point to the grasp action, there were two key findings showing time-dependent changes in motor cortex excitability: first, greater MEP amplitude in FDI during observation of the point than the grasp action at an early time-point (index finger extension) and second, greater MEP amplitude in FDI during observation of the grasp than the point action at a later time-point (hand opening to form a grasp). These results show that excitability of the primary motor cortex is differentially modulated during observation of a point and grasp action, suggesting that the action observation network is engaged in a time-dependent manner during action observation. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the study was to investigate the apparent digestibility coefficient (ADC) of defatted biomass derived from microalgae Nannochloropsis sp. and Desmodesmus sp. when fed to Atlantic salmon postsmolts in seawater. Two experiments, one employing cold‐pelleted and the other employing extruded pellets, were carried out to determine the ADC of dry matter (DM), protein, ash and energy. The test feeds consisted of a fishmeal‐based reference feed and the algal biomass, at a ratio of 70:30, and yttrium oxide as the inert marker. The ADC of DM and protein in fish fed microalgae‐incorporated cold‐pelleted feeds were significantly higher for Nannochloropsis sp. compared with Desmodesmus sp. The Nannochloropsis sp. inclusion in extruded feeds also led to higher ADCs of DM and energy compared with Desmodesmus sp. The extrusion processing significantly increased the ADC of ash in both defatted microalgae biomass, as well as ADCs of DM in Nannochloropsis and protein in Desmodesmus sp. In conclusion, the microalga Nannochloropsis sp. was more digestible than Desmodesmus sp., and extrusion processing can be used as a means to improve digestibility of certain nutrients. [ABSTRACT FROM AUTHOR]

Two marine algal products MAP3 and MAP8 were examined for their suitability as fishmeal protein substitutes in feeds of three prominent farmed species, through short-term feeding studies. Algal meals were tested at 5 and 10% protein replacement levels for Atlantic salmon and at 25 and 40% for common carp and whiteleg shrimp. At the end of the 12-week period, the growth and feed performance of the two fish species did not reveal any significant difference between those fish offered the algae-based feed and those offered the control feed. The whole body proximate compositions of Atlantic salmon fed the control and algae-based feeds were not significantly different. In common carp, the lipid content in the fish fed higher level of MAP3 was significantly lower than that of the fish fed the control feed. In whiteleg shrimp, at the end of the 9-week feeding period, growth performance and feed utilization did not differ between the treatment groups. Protein content in the shrimp fed the higher level of MAP8 was significantly lower than that of shrimp on the control feed. The three species could accept the algal meals in their feeds at the tested levels, though there were some noticeable effects on body composition at higher inclusion levels. [ABSTRACT FROM AUTHOR]

The development of a head-end processing step for spent oxide fuel that applies to both aqueous and pyro-metallurgical technologies is being performed by the Idaho National Laboratory, the Oak Ridge National Laboratory, and the Korean Atomic Energy Research Institute through a joint International Nuclear Energy Research Initiative. The processing step employs high temperatures and oxidative gases to promote the oxidation of UO2 to U3O8. Potential benefits of the head-end step include the removal or reduction of fission products as well as separation of the fuel from cladding. The effects of temperature, pressure, oxidative gas, and cladding have been studied with irradiated spent oxide fuel to determine the optimum conditions for process control. Experiments with temperatures ranging from 500 to 1250°C have been performed on spent fuel using either air or oxygen gas for the oxidative reaction. Various flow rates and applications have been tested with the oxidative gases to discern the effects on the process. Tests have also been performed under vacuum conditions, following the oxidation cycle, at high temperatures to improve the removal of fission products. The effects of cladding on fission product removal have also been investigated with released fuel under vacuum and high-temperature conditions. Results from these experiments will be presented as well as operating conditions based on particle size and decladding characteristics. [ABSTRACT FROM AUTHOR]

Dinoflagellates, which comprise an important part of the phytoplankton in the neritic region of the Southern California Bight, are known to be grazed by Calanus pacificus; rates of ingestion, development and survival of nauplii are influenced by the food quality of dinoflagellates. We have examined the effects of dinoflagellate food quality on reproduction of C. pacificus females sampled in La Jolly Bay (32°N; 117°W) between 6 April and 4 May 1988. Four sets of experiments were conducted in which copepods were fed five different species: Gymnodinium splendens, Gyrodinium resplendens., G. dorsum, Exuviella mariae lebourae and Gymnodinium simplex. These species were selected on the criterion of their success in supporting the growth of nauplii in previous rearing experiments. The experimental culture concentration was maintained at 100 µg C 1, near that of the natural seston. As indices of successful reproduction, we measured the percentage of spawning females and the number of eggs laid per female per day. Laboratory results were compared to stages of ovarian maturation of wild females. Four stages of maturation were determined using histological and microscopic observations. Gymnodinium splendens, Exuviella mariae lebourae, and G. simplex yielded clearly inferior results: few females were able to lay eggs repetitively over the first few days of confinement. Gyrodinium resplendens and, above all, G. dorsum yielded the best results. The stage of sexual maturation in situ appears to influence the rhythmicity of egg-laying events. In the presence of high-quality food, females are able to maintain high reproductive rates by sustaining the maturation of successive batches of eggs; good food quality appears to assure this secondary vitellogenesis and the rapid turnover of ovocytes. [ABSTRACT FROM AUTHOR]

General aviation (GA) fatal accident records of airport transport pilots (ATPs) were compared to those of private pilots (PVTs). ATPs are safer GA pilots than the PVTs. They have comparable exposure in GA airplanes and account for 7·5% of all certified to fly, but only 3·5% of the fatal accidents. ATPs are less often involved in pilot-induced accidents. Nearly 50% of ATP pilot-induced accidents occur during aerobatics. Often these risky aerial operations are performed below a safe altitude and are associated with the descriptors ‘careless’ and ‘reckless’. The ATP aerobatics-related fatality is likely to occur in a multi-wing aeroplane with which he has little experience. The ATP aerobatics-related accident is likely to be of the spin, stall, or controlled flight into terrain variety, and to occur in summer or early autumn. [ABSTRACT FROM PUBLISHER]

Diel vertical migration and feeding cycles of adult female Metridia gerlachei in the upper 290 m of a 335-m water column were measured during a total of 65 h in two periods of early summer (Dec 20-21 and Dec 25-26, 1991). Samples collected in eight depth strata by 35 MOCNESS tows (333-μm mesh) were analyzed for abundance and mean individual gut pigment content. Most of the copepod population was concentrated in a 50-m depth interval at all times. Feeding began simultaneously with nocturnal ascent from a depth of 200-250 m at ≈ 18:00 h (local time), when the relative change in ambient light intensity was greatest. Ingestion rate increased exponentially (k = 0.988 h) at double the gut evacuation rate (k = 0.488 h) as the population moved upward at 22.3-26.5 m h through increasing concentrations of particulate chlorophyll- a. Although the bulk of the population did not move to depths shallower than 50 m, and began its downward migration at a rate of 20.8-31.7 mh in complete darkness, individual females continued to make brief excursions into chlorophyll-rich surface waters (4-8 μg l) during the first few hours of population descent. Ingestion rate diminished abruptly by one order of magnitude (k = 0.068 h) at dawn (≈ 03∶30 h). Within four more hours, the population had reached its daytime depth and gut pigment content remained constant at a minimum value until the next migration cycle. No feeding appeared to take place at depth during the day. Ingestion by M. gerlachei females removed < 4% of daily primary production, with only ≈ 20% of this amount being removed from surface waters by active vertical transport. [ABSTRACT FROM AUTHOR]

Mixed zooplankton were collected in June and July of 1985 and 1986 from La Jolla Bay, California, USA, and experiments were conducted to determine how selected dinoflagellates affect development and survival of nauplius larvae of Calanus pacificus. We raised nauplii from eggs on nine species of dinoflagellates at concentrations generally >300 μg C l, and compared their development and survival to controls reared using the diatom Thalassiosira weissflogii or filtered seawater. Experiments were conducted for 6 d at 17°C. Development and survival rates of the nauplii fell clearly into one of two groups, depending upon the phytoplankton used as food. The first group was characterized by high development rate (0.46 to 0.84 stage d), and by >27% of the original cohort surviving to at least Nauplius IV or V. The five species producing this result were Gymnodinium simplex, G. splendens, Exuviaella marie-lebourae, Gyrodinium dorsum, and T. weissflogii. The second group was characterized by a development rate similar to that in filtered seawater (0.21 to 0.34 stage d), and by nauplii generally failing to molt past the first feeding stage (Nauplius III), often accompanied by high mortality. The five species producing this result were Gyrodinium resplendens, Ptychodiscus brevis, Glenodinium sp., Amphidinium carterae, and Gonyaulax grindleyi. Development rate and survival were not related to cell size or cell carbon, nor to shape or texture (thecate vs athecate dinoflagellates). Poor growth could be related to the absence of some important, but unidentified, nutritional factors. Alternatively, it could be caused by the presence of plant secondary metabolites which are deleterious to growth, a factor we suspect in P. brevis in particular. Prefeeding nauplii exposed to P. brevis lost neuromuscular control prior to becoming lethargic and dying; nutritional deficiencies may not explain these effects. Methods employed in this study provide useful bioassays for detecting chemical interactions between marine plants and animals. Lethal or sublethal effects of dinoflagellates on their most likely potential predators - copepods - may partially explain why they form significant blooms. [ABSTRACT FROM AUTHOR]

Calanus pacificus (Copepoda: Calanoida) females were collected off the California (USA) coast from November 1984-April 1985. A video system was used to observe and record the behavior of restrained individual females presented with a variety of dinoflagellate prey. Two species, Gonyaulax grindleyi and Ptychodiscus brevis, elicited acute physiological reactions. In 40% of the trials ( n=10), copepods fed G. grindleyi regurgitated after 45 to 120 min and, in nearly all cases, did not maintain full guts. Copepods in the presence of P. brevis exhibited rapid heart rate and loss of motor control. Scrippsiella trochoidea elicited an intermediate response by C. pacificus. The copepods occasionally displayed mouthpart twitching or failure to maintain gut fullness. Olisthodiscus luteus elicited no unusual behavior in an intermediate temporal range (sec-hours), although the mouthpart movements appeared different than in copepods fed Gyrodinium resplendens (used as control). Placing the copepods in G. resplendens suspension restored normal feeding behavior in all cases. [ABSTRACT FROM AUTHOR]

We have re-evaluated the experimental methods and statistical procedures used to determine the relationship between feeding rates of pelagic herbivores and food concentration. Analysis of our own experiments, on Calanus pacificus feeding on Gyrodinium resplendens, and of other published research on this subject suggests the need for improvements in experimental design and methodology. We show that the use of 'mean concentration' is statistically erroneous. First, it produces an artificial increase in the degrees of freedom that may result in the acceptance of nonsignificant regression lines. Second, it negates the value of replication, which is required to estimate sources of error. We present an example of how replication may be used to improve control over sources of error. Furthermore, we recommend the use of initial concentration rather than mean concentration. Finally, we introduce alternative methods to determine clearance and ingestion rates that enable the investigator to use replication and thus to estimate experimental errors. [ABSTRACT FROM AUTHOR]

Age-specific differences in diel vertical migration behavior of Calanus pacificus were investigated in a 58 d (30 April-26 June, 1981) experiment in the Scripps Institution of Oceanography Deep Tank, La Jolla, California, USA; the experiment spanned three successive generations of copepods. The onset of vertical migration behavior occurred in the first feeding stage, Nauplius III. The amplitude of vertical migration gradually increased with age, becoming maximal in the late copepodite stages. Night depths remained constant with age while daytime depths increased. The migratory behavior of late copepodite stages was influenced by food availability. When phytoplankton was abundant and individual ingestion rates were high, copepodites performed high-amplitude migrations. As food availability declined, however, and the competition for food increased, migration amplitudes decreased and then ceased altogether so that copepodites remained in the relatively food-rich surface waters at all times. We suggest that hunger is the primary factor controlling vertical migration behavior. [ABSTRACT FROM AUTHOR]

Following consumption of an alcohol or placebo beverage, one group of twelve subjects made familiar and a second group of twelve made novel responses to tachistoscopically presented letters from stimulus groups comprised of two, four or eight letters. It was found that blood alcohol concentrations approximating 80 mg-% have little effect on letter identification times when stimulus-response associations are highly familiar. When associations are novel, identifications times are increased by alcohol and the magnitude of the increase is logarithmic (log) with the number of equally likely stimulus-response pairs. When obtained, alcohol effects retard selection of the identification response rather than influencing stimulus recognition per se. [ABSTRACT FROM AUTHOR]

Using a complete factorial design, choice reaction times of nine subjects were determined in three sessions on each of three days, after having consumed three beverages (placebo, beer, ethanol) with only a single beverage being consumed each day. Reaction time (the time to identify the location of a dot projected on a small screen) was measured from onset of stimulus presentation to the verbalization of a single-digit number associated with the area of the screen upon which the dot was projected. Reaction times were lengthened significantly by alcohol; increases in stimulus-response uncertainty, i.e., the number of possible locations and associated responses; and were lengthened more by alcohol as stimulus-response uncertainty was increased. [ABSTRACT FROM AUTHOR]

Introduction The Complex Care Support Team (CCST) are a newly-formed, integrated service, caring for Croydon residents when existing services decide additional multidisciplinary team input is required. There is no single definition of healthcare complexity. Most cases encountered by the team have involved many different services and professionals. The team have found that by forging relationships and co-ordinating care across organisational boundaries, some of the “complexities” can be mitigated. We aim to develop our understanding of the needs of this population and the underlying drivers for complexity in Croydon. Methods The records on EMIS, CERNER and ePJS were reviewed from the inaugural two months of the service, for: Rockwood Frailty Score Number of medications Number of long-term conditions ED attendances or admissions to hospital over the preceding year. After team discussion on every case, underlying causes of complexity were assigned to four groups: medical, psychological, social and systems failure. Results Of the 57 people accepted by CCST over 2 months, 39 required reviewing in person. 5 records were not completed, so 34 cases were included for evaluation. The age range of this cohort was 49-92, with 17 male and 17 female. Results revealed significant frailty, multimorbidity and polypharmacy. 91% had two or more underlying drivers for complexity, with the largest underlying driver being systems failure, in 85% of cases. Frailty Multimorbidity Polypharmacy Prevalence 72% 97% 76% Range Rockwood score 1-8 1-10 conditions 0-21 medications Mean (score or number) 5.7 5.1 8.4 Conclusions This work improves our understanding of the needs of the population deemed the most “complex” in Croydon. The likelihood of multiple underlying drivers for complexity was high, highlighting how complex health issues are likely to span both professional and organisational boundaries. This can in itself be a significant underlying driver for complexity, illustrated here as “systems failure”. In developing current and future services, this work reinforces the vital benefits of multidisciplinary and cross-organisational working currently occurring in CCST. [ABSTRACT FROM AUTHOR]