Longer Rest Periods Research Articles

The Japanese Experience with Tendonitis in Racehorses.

Superficial digital flexor tendon (SDFT) injury leading to tendonitis is the most frequent soft tissue injury in racehorses. As tendonitis has been noted to heal slowly and imperfectly, injured tendons require long periods of rest, and the rate of recurrence of tendonitis upon return to training is high. Between 1, 100 and 1,200 of the 6,400 to 7,000 racehorses currently registered with the Japan Racing Association (JRA) suffer from tendonitis, and some 70% of these return to racing without making a comeback in a single race. In view of this statistic, the JRA has conducted investigational and clinical research from various perspectives. This paper will review the results of these studies, thus providing insight into practical methods of treating and preventing tendonitis. The study results are summarized under the following headings: 1) Introduction; 2) Impacts and loads on the lower limb at the track; 3) Occurrence of tendonitis at JRA training centers; 4) The hoof and tendonitis; 5) Ultrasonic diagnostic criteria; 6) Therapeutic regimens; 7) Conclusion. We concluded that tendon injuries represent irreversible structural alterations that are unlikely to be significantly altered by therapy, so that the best outcome may be achieved by minimizing the damage done by the original injury. From this viewpoint, research efforts will be directed toward prevention and early diagnosis, rather than therapy of established lesions.

Multifidus EMG and tension-relaxation recovery after prolonged static lumbar flexion.

The electromyogram (EMG) from the in vivo feline L1 to the L7 multifidus was recorded during the application of a 20-minute static lumbar flexion and after 7 hours of rest. To determine the recovery of tension-relaxation and laxity in the lumbar viscoelastic structures as well as the recovery of reflexive EMG activity in the multifidus after prolonged static flexion. It has been established that prolonged static flexion of the spine induces creep or tension-relaxation in its viscoelastic structures as well as a sharp decrease in the reflexive activity of the dorsal musculature and initiation of spasms. Epidemiologic studies have pointed out that such static flexion is associated with unusually high rates of low back disorders. The rate and pattern of recovery of reflexive muscular activity with rest after static flexion is still unknown. The lumbar spines of seven in vivo feline preparations were subjected to 20 minutes of passive anterior flexion followed by 7 hours of rest while monitoring flexion tension, EMG from the L1-L7 multifidus muscles, and the strain of the L4/L5 supraspinal ligament. A model describing the pattern of recovery of muscular activity and viscoelastic tension was developed. Twenty minutes of lumbar flexion was associated with an initial sharp decrease of multifidus EMG activity followed by spasms. During rest, EMG activity demonstrated an initial hyperexcitability on flexion, followed by an exponential recovery of muscle activity. Full recovery of residual strain in the L4/L5 supraspinous ligament and multifidus activity was not obtained after 7 hours of rest. Static flexion of the lumbar spine is an extremely imposing function on its viscoelastic tissues, resulting in spasms and requiring long periods of rest before normal functions are re-established.

The protective effects of hypoxia-induced hypometabolism in the Nautilus.

Specimens of Nautilus pompilius were trapped at depths of 225-300 m off the sunken barrier reef southeast of Port Moresby, Papua New Guinea. Animals transported to the Motupore Island laboratory were acclimated to normal habitat temperatures of 18 degrees C and then cannulated for arterial and venous blood sampling. When animals were forced to undergo a period of progressive hypoxia eventually to encounter ambient partial pressure of oxygen (PO2) levels of approximately 10 mmHg (and corresponding arterial PO2's of approximately 5 mmHg), they responded by lowering their aerobic metabolic rates to 5-10% of those seen in resting normoxic animals. Coincident with this profound metabolic suppression was an overall decrease in activity, with brief periods of jet propulsion punctuating long periods of rest. Below ambient PO2 levels of 30-40 mmHg, ventilatory movements became highly periodic and at the lowest PO2 levels encountered, ventilation occasionally ceased altogether. Cardiac output estimated by the Fick equation decreased during progressive hypoxia by as much as 75 80%, and in the deepest hypometabolic states heart rates slowed to one to two cycles of very low amplitude per minute. By the end of 500 min exposure to ambient PO2 levels of 10 mmHg or less, the anaerobic end products octopine and succinate had increased significantly in adductor muscle and heart, respectively. Increased concentrations of octopine in adductor muscle apparently contributed to a small intracellular acidosis and to the development of a combined respiratory and metabolic acidosis in the extracellular compartment. On the other hand, increases in succinate in heart muscle occurred in the absence of any change in cardiac pHi. Taken together, we estimate that these anaerobic end products would make up less than 2% of the energy deficit arising from the decrease in aerobic metabolism. Thus, metabolic suppression is combined with a massive downregulation of systemic O2 delivery to match metabolic supply to demand.

WORK-REST REGIMEN AND NIGHT/DAY REGIMEN - TWO NEW FUNCTIONS IN A NEW CARDIOMYOSTIMULATOR (LD-PACE II) DESIGNED FOR CARDIAC BIOASSIST

LD-PACE II, a new cardiomyostimulator was manufactured by CCC del Uruguay with the support of the Illini Group, Chicago, Illinois. The LD-PACE II was designed for use in cardiomyoplasty, aorto myoplasty, and skeletal muscle ventricle. All parameters specified as programmable can be changed in a noninvasive manner (using a programming interface wand connected to a computer using the Windows 95/98 environment). Most of the functions of the new stimulator are similar to functions of previously used devices (Transform, Medtronic; EKS 445, Russia), however new two functions could be extremely important fo clinical use based on experimental research. 1. Work-rest regimen. In the conventional stimulation regimen, the latissimus dorsi muscle (LDM) works 24 hours daily with no rest except for short periods between contractions. The LD-PACE II is able to deliver alternating periods of muscle contractions and rest. Work and rest periods may be programmed independently between 1 and 120 minutes in increments of one minute. The work-rest regimen may be useful clinically if muscle contractions are needed for cardiac assist postoperatively. Morphological (light microscopy, transmission electron microscopy) and electrophysiological data show that a short period of work followed by a long period of rest does not damage the ischemic muscle. 2. Night/day regimen. This feature is also brand new. It allows for a change in the ratio of muscle contractions according to a patient's activity level. During the day the cardiosynchronization ratio may be set from 1:1 to 1:4 and during the night it may be set for 1:8 to 1:16. This allows the LDM to have a long rest period, prevents overuse, and prolongs battery life. Data confirmed that there is no depression in hemodynamics when the ratio is slowed or turned off during the night. The first tests of the LD-PACE II in Milwaukee, WI, Detroit, MI and Paris (France) showed good functional ability of a high caliber.

APPLICATION OF 40Ar/39Ar AND 230Th DATING METHODS TO THE CHRONOSTRATIGRAPHY OF QUATERNARY BASALTIC VOLCANIC AREAS: THE USTICA ISLAND CASE HISTORY

Abstract The island of Ustica has been the site of coeval volcanism and transgressive–regressive marine cycles. The volcanic history can be subdivided into five periods of activity according to stratigraphical and compositional data. Basaltic magmas were extruded during most of these periods and only one period was characterized by the emplacement of trachytic rocks. Sea level high-stands generated five orders of marine terraces with related level surfaces at variable elevation and sedimentary deposits. A geochronological study was carried out by means of 40 Ar/ 39 Ar and 230 Th dating methods on magmatic and marine sedimentary rocks, respectively. The results obtained allow us to give temporal constraints for the geological history of the island. Volcanism took place between about 750 and 130 ka BP. Until about 500 ka BP, Ustica was a seamount with subaqueous eruptions. The sole trachytic explosive eruption occurred about 424 ka BP, after a long period of rest during which the conditions for formation and evolution of a shallow magma chamber were established. The ages of the marine terraces are in very good agreement with those obtained for correlatable level surfaces along the coasts of the southern Tyrrhenian sea. The I-order marine terrace (80–120 m a.s.l.) was created about 350 ka BP, while the III-order terrace (20–30 m a.s.l.), which is the youngest dated, formed around 130 ka BP. According to geomorphological constraints, the IV-(10 m a.s.l.) and V-order terraces (5 m a.s.l.) are correlated with level surfaces dated at 105 and 80 ka BP.

Getting from how to why: a pause for reflection on professional life.

In the course of institutional life, many may lose their sense of purpose. The daily demands of both medicine and teaching--small defeats, time pressures, bureaucratic obstacles, and chronic overload--can erode the sense of purpose and clarity of desire that infuse work with spirit and energy. One antidote for this drained state is time for renewal--not long periods of rest and relaxation, valuable though these may be, but rather a "particular kind of stopping . . . the pause for a poem." The author describes how stopping in the middle of the day to read and reflect on a poem can defamiliarize the familiar, giving the reader a fresh outlook on the ordinary day. She describes how poetry also can awaken a sense of play, a childlike openness and sense of curiosity, and a renewed awareness of feelings. To honor feeling can provide a needed corrective to the conventionalized response that has become thoughtless or bloodless or tired. The kind of play poems engage readers in can also provide a connection to the sacred, restoring the wider vision and deeper purposes without which the practice of medicine might diminish to something less lifegiving for both patient and physician than it ought to be. In her discussion of the restorative power of poetry, the author quotes several poems in full and invites readers to consider the fresh perspectives they offer.

Variation in Eastern Gamagrass Forage Yield with Environments, Harvests, and Nitrogen Rates

AbstractEnvironmental variation, and the interaction of environment with management practices, can significantly affect perennial forage yields. The objective of this research was to evaluate the importance of environmental main effects and the interaction between environments, N rates, and harvests on eastern gamagrass [Tripsacum dactyloides (L.) L.] forage yields. Established eastern gamagrass stands were fertilized with 0, 168, or 336 kg N ha−1, and harvested three times during the growing season for three consecutive years at two locations in northern Missouri. Year and the year × location interaction were significant environmental sources of variation affecting forage yields. The year main effect had the larger variance component and accounted for 9% of the total variation in forage yields. The harvest main effect and year × harvest interaction had the largest variance components, and together accounted for more than 67% of the total variation in forage yields. Most of the variation between harvests resulted from differences in first‐harvest yields, taken at the reproductive growth stage, compared with regrowth harvest yields which were at vegetative growth stages. Variation in precipitation amounts between harvests significantly influenced regrowth harvest yields, causing a significant year × harvest interaction. Forage yield responses to N rates also varied between years, causing a significant year × N rate interaction. Location was not an important source of variation in eastern gamagrass forage yield in this study, nor was there a significant interaction between N rates and harvests. Resultsuggest that supplemental irrigation and longer rest periods between harvests may help improve forage yields and distribution.

Mechanical back pain and the facet joint syndrome.

Mechanical back pain is a common disability often associated with the facet joint syndrome. Treatment is based on early, adequate pain relief with simple techniques of regional analgesia. In a few cases this is not enough and more sophisticated methods, such as radiofrequency denervation, cryo-analgesia and possibly intrathecal midazolam, are necessary. However, the main thrust of our approach is to treat the underlying structural disorder with strengthening of the back muscles and correction of postural abnormalities responsible for the mechanical back pain. Our report is based on an analysis of 83 patients who failed to respond to long periods of rest, suitable analgesic and allied drugs and other non-invasive measures. There had been no overriding indication for major surgery. A large number of these patients have been improved by our methods, but further work is in progress to extend the proportion of satisfactory results.

Design concepts of high power bipolar rechargeable lithium battery

The present study shows that current bipolar Li/TiS 2 batteries using a 0.38 mm thick TiS 2 bipolar plate, can yield moderate specific power and also high specific energy battery. The computer design studies project that a 100 V, 10 A h bipolar Li/TiS 2 battery can achieve 150 W h/kg, 210 W h/l, and 150 W/kg. The unoptimized experimental bipolar Li/TiS 2 batteries (3 cells, 90 mA h) exhibited 47 W h/kg, 90 W h/l, and 140 W/kg. Preliminary results on the cycleability of the bipolar batteries were demonstrated. The results also show that enhanced rate capability can be achieved by using pulse discharge and longer rest period between pulses.

Les dyspnées aiguës hautes en effort sportif. Contribution à la recherche étiotopographique

Les dyspnées en effort sportif sont des épiphénomènes apparemment courants. Considérées comme un phénomène normal conjugué à l'effort, elles sont le plus souvent négligées, tant du point de vue du suivi médicosportif, que par les intéressés qui ne sont pas toujours demandeurs. Ces dyspnées peuvent cependant être handicapantes, voire mortelles: l'effort extrême fourni lors des compétitions peut échapper au contrôle propre du sportif. Il est alors littéralement emporté par son effort et l'organisme n'arrive plus à suivre. Ici pourrait se trouver l'une des explications possibles des morts subites sur stade, avec autopsie blanche. Le diagnostic topographique et étiologique de ces dyspnées en effort intense est le plus souvent présomptif. En effet, la symptomatologie — bien que bruyante — est fugace, et ne permet pas les explorations au moment souhaité. L'apport de la vidéofibroscopie avec enregistrement, en «test réaliste à l'acmé de l'effort déclenchant, confronté à l'examen clinique de repos et aux divers examens complémentaires d'exploration, a permis de poser le diagnostic de certitude de dyspnée haute, laryngée ou trachéale. Nous rapportons ici trois cas cliniques de dyspnée en effort sportif, qui ont posé des problèmes diagnostiques. Cette méthodologie nous a permis un diagnostic à l'examen direct, enregistré, lors du déclenchement du phénomène; de réorienter les thérapeutiques non adaptées; de faire reprendre confiance aux patients en leur donnant une explication plausible du leur état, et surtout, de gérer leur reprise sportive ou compétitive, soit en prévenant les sur-efforts trop hâtifs ou trop rapides, soit en interdisant temporairement ou définitivement la compétition. Acute dyspnea in exercise is frequent, but its diagnosis and etio-topography are often difficult, because of no asking for from the athlete, nor the physicians. We have studyed the case of three patients who suffered from acute dyspnea, which affected their sporting performance. After diverse explorations including respiratory tests, cardiovascular tests and allergic tests, these patients were classified as having “exercise-induced asthma” and were treated as such, but without result. Our methodology consists of reproducing the symptoms in registered video-endoscopy with optic fibre, undertaken during testing. This permits us to rectify and give an etiotopographic diagnosis. The first patient, a young racing cyclist, was seen the first time for repeated acute dyspnea during racing, which obliged him to stop. Previous history included frequent breaks in his sporting activity due to numerous traumatisms. Following various tests, he was classified as having “exercise induced asthma”, although treatment did not give any results. The subject was rediagnosed as having laryngeal and tracheal dyskinesia. The second patient, a teenager, suffered from acute dyspnea whilst participating in school sports. All investigations carried out previously did not show any abnormalities. The patient had also had a long period of rest due to illness. Her problems began following this inactivity. She was also classified as having “exercise-induced asthma”, but did not respond to treatment. Following video-endoscopy, we rediagnosed the patient as having stridor and vocal dyskinesia. The third patient was a nineteen year- old woman, racing roller skater, with no previous surgical treatment apart from an operation on her alves. Following the operation, she complained of discomfort with dyspnea and also felt faint. During tests, we observed the appearance of “laryngomalacy during exercise”. Diagnosis permits us to classe the correct therapy and to manage sporting recovery. It must not be forgotten that these dyspnea may be fatal, and their urgen therapy is invasive: intubation, tracheotomy. In addition their screening, diagnosis and prevention are essential: it is important that they be distinguished from exercise-induced asthma, the diagnosis must not be presumptive (thinking of other possible extra-thoracic origins), and registered video-fiberscopy should be used during testing, which is the only method to verify the diagnosis.

Reliability of Isokinetic Measurements of Trunk Muscle Performance

The purpose of this investigation was to assess the reliability of isokinetic trunk muscle performance. Sixty-one volunteers participated (29 men, 32 women; age range, 20-60 years). All subjects were without low-back symptoms at the time of testing. All testing was performed with the subject initially standing, using speeds of 60, 120, and 180 degrees per second. Ten repetitions of flexion and extension were performed reciprocally at each speed, with a 3-minute rest period between speeds. Test-retest intervals were 1 and 3 weeks from the initial test. Peak torque-to-body-weight ratios, extension-to-flexion ratios, and average work per repetition were calculated for each speed for flexion and extension. Data were analyzed with analysis of variance, intraclass correlation coefficients, and Pearson correlation coefficients. Intraclass correlation coefficient values ranged from .74 to .88 for measurements derived from peak torque, and from .88-.93 for measurements derived from work (with the exception of .69 for men at 180 degrees/sec). Standard error of measurements ranged from 8 to 32 ft-lb, with a tendency to increase with increasing speeds. It was concluded that, when using this protocol, isokinetic measurements of muscle function offer the clinician sensitive and reliable measurements of trunk muscle performance and that incorporating increased practice with women and longer rest periods with men may further decrease error associated with these isokinetic trunk strength measurements.

Effects of thermal environment and chemical protective clothing on work tolerance, physiological responses, and subjective ratings

This study examined the physiological and subjective responses of nine healthy men who performed work while wearing two types of protective ensembles in each of three thermal environments. The subjects, all experienced with the use of protective ensembles, each performed low intensity treadmill exercise (23% of VO2 max while not wearing a Self-Contained Breathing Apparatus [SCBA] or protective clothing) under six experimental conditions: two ensembles (SCBA--light work clothing and SCBA; and CHEM--a two-piece chemical protective ensemble with SCBA) during exposure to 'cool' (10.6 degrees C/water vapour pressure [Pw] 0.76 kPa), 'neutral' (22.6 degrees C/Pw 1.52 kPa), and 'hot' (34 degrees C/Pw 2.90 kPa) environments. Each test was intended to continue for 120 min; however the duration and number of work/rest periods within the testing session varied according to the specific responses of each individual. At the completion of each test seven subjective responses were recorded. Physiological data, collected every minute during each test, included heart rate, and skin and rectal temperature. The total worktime was significantly shorter in the hot environment while wearing the CHEM ensemble (53.4 min) compared to all the other conditions (103-105 min). The mean maximum physiological values also indicated significant differences due to thermal environment and/or ensemble. Work performance did not appear to be limited in a cold environment with either ensemble tested. The physiological responses to working in the CHEM/neutral condition were very similar to those occurring in a hot environment wearing the SCBA ensemble. The subjective responses also indicated significant differences due to thermal environment and ensemble, with subjects perceiving the CHEM ensemble as less favourable than the SCBA ensemble. The results suggested that, even at a low work intensity, individuals wearing chemical protective clothing in the heat will require progressively shorter work periods, and more frequent and longer rest periods.

The value of subtropical grass pastures for use as foggage on the eastern Transvaal Highveld

The utilization of frosted herbage of Pennisetwn clandestinwn, Paspalum notation, Digitaria eriantha, Cynodon sp. and Chloris gayana by Merino wethers during the winter confirmed the potential of this practice as an alternative winter feeding strategy under Highveld conditions. P. clandestinwn and P. notatum provided good quality foggage with average daily gains of 60–80 g sheep−1 being recorded. D. eriantha also provided good quality foggage when stem production was minimized. C. gayana gave good livestock performance, but did not persist under Highveld conditions. Although Cynodon sp. proved to be a relatively poor foggage species, it provided for the maintenance of livemass. Longer rest periods in the growing season increased the available pasture, grazing capacity and livestock production ha−1, but increased the probability of poorer livestock performance. This is probably linked with a lower protein content and a higher proportion of stem material in herbage rested for a longer period.

Effects of Different Weight Training Routines on Mood States

An experiment was designed to determine if two frequently-used weight training protocols differentially affect mood state in novice lifters, possibly also influencing adherence to training programs. Mood states of nine males and nine females were examined before and after six different weightlifting workouts, varied according to interset rest interval (one versus three minutes), total work (low versus high), and weight lifted (light for 10 repetitions per set versus heavy for five repetitions per set). The Profile of Mood States was given two minutes pre-, and at two minutes, two hours, 24 hours and 48 hours post-workout. Stronger perception of negative moods including tension, depression and fatigue resulted from higher work, lower weight with higher repetitions per set and shorter inter-set rest periods. With the lower weight, higher total-work routine, the one-minute rest period produced more tension and depression than the three-minute routine, probably due to physical fatigue. In contrast, for the heavier weight, lower total-work routine, three minutes of rest produced more tension and depression than did one minute, possibly because of impatience brought on by the longer rest periods when fatigue was minimal. In conclusion, for novice lifters, the 5 RM, lower total work type routine with an inter-set rest period of three minutes is likely to produce relatively high rates of compliance and low attrition.

Die palliative operative therapie pathologischer frakturen

From 1971 through 1985, 97 patients with pathological fractures were operated at the Giessen University Hospital for Accident Surgery. The palliative operations were intended to relief pain, to prevent long periods of bed rest for the patients, to restore the loading capacity of the lower extremity as well as the mobility of the upper extremity. The preservation or restoration of the patients general mobility in everyday life and the psychological aid for the patients had to be considered as well. In case of primary tumors, pathological fractures as a result of formation of metastases are most frequently induced by mammary carcinomas, followed by bronchial carcinomas, hypernephromas, colon carcinomas, and plasmocytomas. The preferential sites of metastases are the proximal femur area, the femur shaft, the humerus, and the pelvis. In our palliative operations, we applied 43 compound osteosyntheses, 23 endoprostheses, 17 resections, 10 marrow nailings, 4 Ender nailings or multiple bone nailings, respectively. One patient underwent a stabilization of the femur neck by means of a strap nail and another patient a stabilization of the spine by spondylodesis. Excisions were performed in 7 cases. The average survival was between 24 and 52 weeks.

Work at sea: a study of sleep, and of circadian rhythms in physiological and psychological functions, in watchkeepers on merchant vessels. VI. A sea trial of an alternative watchkeeping system for the merchant marine.

A trial of an alternative to the traditional 4-on/8-off watchkeeping system was made on a container ship during a round trip from Europe to the Far East. The three navigating officers on the ship operated the new system, which involved "compressed" working hours with a long unbroken period of rest, during two sections of the voyage, one of which included six stops at ports. Despite unforeseen problems arising mainly from these stops, questionnaire responses concerning the new system were not altogether unfavourable to it, and daily records kept by the officers gave some support to the hypothesis that sleep would be better than under the traditional system. However, a number of difficulties were encountered; these are discussed in relation to the design of future studies of alternative watchkeeping systems.

Seasonal Time-Energy Budgets of Free-Living Chukars in the Negev Desert

Chukars (Alectoris chukar) have a broad Palearctic distribution which includes mesic and semi-arid, but not very hot, arid areas. We studied the seasonal activity patterns of Chukars in the Negev desert highlands of Israel, and examined whether their ability to inhabit hot, dry areas is influenced by limitations imposed on their activities by the physical environment. Daily energy expenditure (DEE) of Chukars (350 to 550 g body mass) was calculated by converting time-activity budgets to time-energy budgets, and by using the operative environmental temperature (Te) to estimate the Chukar's thermoregulatory requirements. Mean DEE of Chukars was 630 kJ/(kg-day) in summer when they foraged mainly on high energy foods in cultivated fields, and 960 kJ/(kg.day) in winter when they ate mainly natural vegetation of lower energy content. Consequently, Chukars spent twice as much time foraging in winter than in summer (7 to 8 hr/day vs. 3 to 3.5 hr/day). The Chukars' activity pattern during summer was bimodal, characterized by long periods (7 to 8 hr/day) of rest in the shade during the hot part of the day. A significant positive correlation was found between time spent resting and mean daily maximum Te (Te,ma.) and a significant negative correlation was found between time spent foraging and Te,ma. We concluded that the geographical distribution of Chukars is limited by a combination of two key factors: the duration of time that Chukars can remain active without risking their heat balance and the amount of time they need to find and eat enough food to meet their daily energy requirements.

腰部脊柱管狭窄症の観血的治療経験

Low back pain accompanied with degenerative lumbar spine is an important problem as well as cauda equina syndrome for lumbar spinal canal stenosis. The purpose of the surgical intervention is to decompress the neural stractures without spoiling stability of the lumbar spine. In point of this purpose, Wedge's osteotomy is one of the ideal methods for laminectomy. Multiple fenestration at the narrow interlaminar segments is a new method.We treated nineteen cases of the lumbar spinal canal stenosis surgically from 1982 o 1986 in our hospital. Central laminectomy was done in one case, Modified Wedge's osteotomy in eleven cases, multiple fenestration in five cases, anterior interbody fusion in two cases. Posterior spinal fusion was done in three cases of laminectomy, and in all cases of multiple fenestration. Harrignton distraction rod was employed in two cases, Harrignton compression rod in one case, and L-type rod in two cases.Good results were obtained concerning involvement of the cauda equina. But one case accompanied with cervical spondylotic myelopathy and one case with thoracic spinal cord tumor developed left paraparesis as sequelae due to spinal cord involvement. Low back pain was deteriorated postoperatively in two cases of laminectomy without fusion.One was a case of degenerative spondylolisthesis. In another one, postoperative stress ulcar occurred and long period of rest in bed was required.Instrumentation gave stability to the spinal column immediately after surgery and was able to make postoperative care easy.

Hunting behaviour of the perlid stonefly nymph Dinocras cephalotes (Plecoptera) under different light conditions

The hunting behaviour of Dinocras cephalotes nymphs was studied during two different light intensities, darkness and twilight (0·1 cd m −2). Nymphs of the mayfly Baetis rhodani were provided as food. In darkness the predator moved slowly without stopping, encountering the prey with the antennae and the hair fringes on the tibiae. Little time was spent in a shelter. There was little tendency to pursue the prey after a missed first attack and the pursuing distance was short. In twilight the speed of the predator was higher and the movement was interrupted by long periods of rest. The number of successful attacks was higher and more attacks were initiated when the predator was immobile. Time of activity outside the shelter was short. There was a greater tendency to pursue the prey after a missed first attack and the pursuing distance was longer compared with that in darkness. There are two main advantages of changing strategy from ‘searcher’ in darkness to ‘ambusher’ in the light: to avoid being detected by predators hunting by vision and to avoid being detected by potential prey species relying on visual cues for the detection of predators. The optical design of the eye revealed that only those parts of the eye directed upwards and backwards were optimized to the light conditions at which the predator preferred to be active, suggesting that the main function of these areas is to detect predators, though an additional gain in detecting prey could also be seen.

Activity patterns of terrestrial gamebirds in the Willem Pretorius Game reserve, Orange Free State

Activity patterns of the Natal francolin (Francolinus natalensis), Swaison’s francolin (F. swaisoni) and the crowned guinea-fowl (Numida meleagris) appear to be influenced mainly by climatic conditions, either directly or indirectly. Diurnal activities are characterised by early-morning and late-afternoon peaks and long periods of rest during the middle of the day. Feeding is the most important activity of the birds, followed by maintenance and strenuous activities. Seasonal and species-specific preferences in the use of shade apparently play an important thermoregulatory role. In comparison to behaviour patterns carried out in direct sunlight, shade-associated behaviour tends to a greater extent to be dominated by maintenance activities, especially during the wet season.