Assessing Activity and Location of Individual Laying Hens in Large Groups Using Modern Technology

Tracking individual animals within large groups is increasingly possible, offering an exciting opportunity to researchers. Whereas previously only relatively indistinguishable groups of individual animals could be observed and combined into pen level data, we can now focus on individual actors within these large groups and track their activities across time and space with minimal intervention and disturbance. The development is particularly relevant to the poultry industry as, due to a shift away from battery cages, flock sizes are increasingly becoming larger and environments more complex. Many efforts have been made to track individual bird behavior and activity in large groups using a variety of methodologies with variable success. Of the technologies in use, each has associated benefits and detriments, which can make the approach more or less suitable for certain environments and experiments. Within this article, we have divided several tracking systems that are currently available into two major categories (radio frequency identification and radio signal strength) and review the strengths and weaknesses of each, as well as environments or conditions for which they may be most suitable. We also describe related topics including types of analysis for the data and concerns with selecting focal birds.

Net community production, Thorium-234 activity and particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km**2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to >0.40. Silicic acid (<2 µmol/L) limited diatoms, which contributed <10% of phytoplankton biomass. Copepods exerted high grazing pressure. This is the first study of particle flux out of an artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC/m**2/d, probably ±20%. 234Th profiles implied constant export of ~6.3 mmol POC/m**2/d in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly <1.1 mmol POC/m**2/d, predominantly of fecal origin; flux did not increase upon fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.

Activity and biomass of small benthic biota in the central Arctic Ocean

Sediment samples collected during the expedition "Arctic Ocean '96" with the Swedish ice-breaker ODEN were investigated to estimate for the first time heterotrophic activity and total microbial biomass (size range from bacteria to small metazoans) from the perennially ice-covered central Arctic Ocean. Benthic activities and biomass were evaluated analysing a series of biogenic sediment compounds (i.e. bacterial exoenzymes, total adenylates, DNA, phospholipids, particulate proteins). In contrast to the very time-consuming sorting, enumeration and weight determination, analyses of biochemical sediment parameters may represent a useful method for obtaining rapid information on the ecological situation in a given benthic system. Bacterial cell numbers and biomass were estimated for comparison with biochemically determined biomass data, to evaluate the contribution of the bacterial biomass to the total microbial biomass. It appeared that bacterial biomass made up only 8-31% (average of all stations = 20%) of the total microbial biomass, suggesting a large fraction of other small infaunal organisms within the sediment samples (most probably fungi, yeasts, protozoans such as flagellates, ciliates or amoebae, as well as a fraction of small metazoans). Activity and biomass values determined within this study were generally extremely low, and often even slightly lower than those given for other deep oceanic regions, thus characterizing the seafloor of the central Arctic Ocean as a "benthic desert". Nevertheless, some clear trends in the data could be found, e.g. generally sharply decreasing values within the sediment column, a vague tendency for declining values with increasing water depth of sampling stations, and also differences between various Arctic deep-sea regions.

Virtual car accidents of epilepsy patients, interictal epileptic activity, and medication.

OBJECTIVE To investigate effects of interictal epileptic activity (IEA) and antiepileptic drugs (AEDs) on reactivity and aspects of the fitness to drive for epilepsy patients. METHODS Forty-six adult patients with demonstration of focal or generalized bursts of IEA in electroencephalography (EEG) readings within 1 year prior to inclusion irrespective of medication performed a car driving computer test or a single light flash test (39 patients performed both). Reaction times (RTs), virtual crashes, or lapses (RT ≥ 1 s in the car or flash test) were measured in an IEA burst-triggered fashion during IEA and compared with RT-measurements during unremarkable EEG findings in the same session. RESULTS IEA prolonged RTs both in the flash and car test (p < 0.001) in individual patients up to 200 ms. Generalized IEA with spike/waves (s/w) had the largest effect on RT prolongation (p < 0.001, both tests), whereas mean RT during normal EEG, age, gender, and number of AEDs had no effect. The car test was better than the flash test in detecting RT prolongations (p = 0.030). IEA increased crashes/lapses >26% in sessions with generalized IEA with s/w. The frequency of IEA-associated RT >1 s exceeded predictions (p < 0.001) based on simple RT shift, suggesting functional impairment beyond progressive RT prolongation by IEA. The number of AEDs correlated with prolonged RTs during normal EEG (p < 0.021) but not with IEA-associated RT prolongation or crashes/lapses. SIGNIFICANCE IEA prolonged RTs to varying extents, dependent on IEA type. IEA-associated RTs >1 s were more frequent than predicted, suggesting beginning cerebral decompensation of visual stimulus processing. AEDs somewhat reduced psychomotor speed, but it was mainly the IEA that contributed to an excess of virtual accidents.

Modeling and participation: elements in education to reduce alcohol impaired driving. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

An analysis of ASAP patrol activity and enforcement. Analytic study 3. Final study.

National Highway Traffic Safety Administration, Office of Driver and Pedestrian Programs, Washington, D.C.

Photographic investigation of sediment texture, bottom current activity, and benthonic organisms in the Wilmington Submarine Canyon, U.S.C.C.C. Rockaway-Smithsonian Institution cruise (RoS2) December 1967

"CG 373-22."

Pharmacological activity and clinical use of sulfanilamide, sulfathiazole and sulfapyridine in veterinary medicine.

Mode of access: Internet.