Effects of nematode parasitism on activity patterns in first-season grazing cattle

An integrated management system involving cattle, ewes and lambs developed to minimise levels of parasitic nematode contamination of pasture was evaluated in a 2-year (1989-1991) study. Four experimental farmlets were managed as self-containcd units over a May-May year. Over the two years, stocking rate averaged 15 su/ha and cattle:sheep ratio 35:65. Three treatments (lambs regularly drenched, ewes drenched post-lambing/ lambs undrenchedand undrenchedewes andlambs) were similarly managed (set-stocked, lambing to weaning, 7-day shifts post-weaning, a 77-day interval between consecutive lamb grazings and a strict rotation of lambs followed by ewes with cattle midway between the ewe and subsequent lamb grazing). A fourth treatment differed in each year: in year 1, lambs were set stocked over summer and in year 2 cattle followed lambs, and ewes were positioned mid-way in the rotation between lambs and cattle, In both years, the management system developed to minimise nematode parasitism in lambs mamtained low levels of infective larvae on pasture (~80 L3 larvae/kg pasture), and a faecal egg count in lambs of less than 1500 epg; clinical parasitism was not observed. However, regular anthelmintic drenching of lambs significantly (P~0.01) increased liveweight gain of lambs from weaning in November to May by an average 35% over the 2 years. In year two, grazing ewes ahead of lambs significantly increased (PcO.01) pasture larvae levels and lamb faecal egg counts and decreased liveweight gain compared with grazing cattle ahead. Drenching ewes to minimise effects of the post-parturient rise in faecal egg count had no influence on nematode levels in lambs or on lamb performance. Keywords parasitic nematodes, grazing management, lamb growth

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Predicting spatial activity patterns in a neural map from a probabilistic atlas of 3-D reconstructed neurons

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140439 ◽

1995 ◽

Vol 53 ◽

pp. 812-813

Author(s):

G. Jacobs ◽

F. Theunissen

Keyword(s):

Activity Patterns ◽

Three Dimensional ◽

Sensory System ◽

Neural System ◽

Probabilistic Atlas ◽

Uniform Sample ◽

Dimensional Reconstruction ◽

The Time Domain ◽

And Function ◽

Visualization Techniques

In order to understand how the algorithms underlying neural computation are implemented within any neural system, it is necessary to understand details of the anatomy, physiology and global organization of the neurons from which the system is constructed. Information is represented in neural systems by patterns of activity that vary in both their spatial extent and in the time domain. One of the great challenges to microscopists is to devise methods for imaging these patterns of activity and to correlate them with the underlying neuroanatomy and physiology. We have addressed this problem by using a combination of three dimensional reconstruction techniques, quantitative analysis and computer visualization techniques to build a probabilistic atlas of a neural map in an insect sensory system. The principal goal of this study was to derive a quantitative representation of the map, based on a uniform sample of afferents that was of sufficient size to allow statistically meaningful analyses of the relationships between structure and function.

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Inducing Unconscious Stress

Journal of Psychophysiology ◽

10.1027/0269-8803/a000247 ◽

2020 ◽

Vol 34 (3) ◽

pp. 192-201

Author(s):

Melanie M. van der Ploeg ◽

Jos F. Brosschot ◽

Markus Quirin ◽

Richard D. Lane ◽

Bart Verkuil

Keyword(s):

Repeated Measures ◽

Activity Patterns ◽

Physiological Changes ◽

Implicit Measures ◽

Prime Word ◽

Student Sample ◽

Priming Task ◽

Subject Design ◽

The Relationship ◽

Stress And Health

Abstract. Stress-related stimuli may be presented outside of awareness and may ultimately influence health by causing repetitive increases in physiological parameters, such as blood pressure (BP). In this study, we aimed to corroborate previous studies that demonstrated BP effects of subliminally presented stress-related stimuli. This would add evidence to the hypothesis that unconscious manifestations of stress can affect somatic health. Additionally, we suggest that these findings may be extended by measuring affective changes relating to these physiological changes, using measures for self-reported and implicit positive and negative affectivity. Using a repeated measures between-subject design, we presented either the prime word “angry” ( n = 26) or “relax” ( n = 28) subliminally (17 ms) for 100 trials to a student sample and measured systolic and diastolic BP, heart rate (HR), and affect. The “angry” prime, compared to the “relax” prime, did not affect any of the outcome variables. During the priming task, a higher level of implicit negative affect (INA) was associated with a lower systolic BP and diastolic BP. No association was found with HR. Self-reported affect and implicit positive affect were not related to the cardiovascular (CV) activity. In sum, anger and relax primes elicited similar CV activity patterns, but implicit measures of affect may provide a new method to examine the relationship between (unconscious) stress and health.

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