Changes in metabolic activity in the hyperstriatal regions of the chick forebrain have been assessed just prior to and after hatching using [14C] 2-deoxyglucose (2-DG) autoradiography. Embryos were injected on day E19, followed by either exposure to light for 30 min or being held in darkness. Other embryos were injected ...

OBJECTIVE: We examined the potential teratogenic effect of endoscopic white light on the developing visual pathways. STUDY DESIGN: The right eye of chicken embryos (n = 22) was exposed to maximal endoscopic light intensity on day 10 of development. At day 17 of development the histologic characteristics of the light-exposed ...

Male Djungarian hamsters with previous light experience of long photoperiods of 16 h of light per day (16L:8D) or short photoperiods (8L:16D) were transferred either to the opposite photoperiods or to intermediate photoperiods (14L:10D). It was demonstrated that the same intermediate photoperiod could exert inhibitory or stimulatory effects on coat ...

Echinostoma trivolvis eggs developed to mature miracidia in both dark and light culture conditions as early as 7 days. Hatching initially occurred in eggs exposed to incandescent light on day 11. Those exposed to fluorescent light first hatched on day 13. Maximum hatching (50+ miracidia/day) lasted only over a 3-day ...

Small (<30 g) juvenile rainbow trout (Oncorhynchus mykiss) possess retinal photoreceptor mechanisms sensitive to light in the near ultraviolet, short (blue), middle (green) and long (red) wavelengths. During normal development, the ultraviolet cone mechanism gradually disappears until, by approximately 60&shy;80 g, individuals are no longer sensitive in the ultraviolet. This ...

We investigated the photoperiodic response to T-cycles (0.5 h of light at intervals ranging from 23.0 h to 25.3 h) of two phenotypes of Djungarian hamsters that either exhibit or lack physiological short-day adjustments under a photoperiod of 9 h light:15 h darkness. Illumination of the same circadian time caused ...

A two-way selection program, carried out for high and low threshold BW at onset of lay (ThrWtLay), decreased photoperiodic drive of the high line (HL) relative to the low line (LL). Photoperiodic drive in modern broiler breeder females was compared to layer females in experiments using the HL and LL ...

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in ...

In a study of the quantitative relationship between ambient light and depression in winter seasonal affective disorder, 13 outpatients and 13 normal comparison subjects each wore a light monitor for 1 week. The patients and normal subjects showed similar light exposure profiles; among the patients, severity of depression was inversely ...

(In En) ICCV 10 was developed by pedigree breeding from a cross P 1231 X P 1265. It has semi-erect growth habit with long fruiting branches. Its stem is purplish green. Its compound leaves are dark green with medium-size leaflets. It has pink flowers and light yellow pods. ICCV 10 ...

Thyroidectomy results in the suppression of reproductive photoperiodic responses in starlings. Could this be a consequence of an effect on perception of daylength or on circadian pacemakers? Daily changes in plasma melatonin concentrations were monitored in intact and thyroidectomized starlings held in long days (LD 16:8) and short days (LD ...

1. The paper compares between three genetically different lines in their egg weight and shell thickness response to a 28-h cycle. 2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d). 3. Differences between genotypes were evident in both the ...

The stability of octreotide acetate in polypropylene syringes was studied. Polypropylene syringes were aseptically filled with 1 mL of octreotide acetate 0.2 mg/mL and stored at 3 or 23 degrees C under light protection or light exposure. Three syringes were prepared for each condition and each sampling time. Unopened 5-mL ...

The role of photoperiod in the entrainment and synchronization of the reproductive cycle of male hedgehogs, seasonal breeders and hibernating mammals, was investigated. Groups of adult hedgehogs were either maintained outdoors (controls, n = 6) or submitted to accelerated 6-month artificial light regimens under constant ambient temperatures (20 +/- 2 ...

Siberian hamsters undergo gonadal development for several weeks after exposure to a single longer day at weaning. To characterize changes in gonadotropin secretion after a single acute light stimulus, hamsters housed in a long photoperiod (16L:8D) were given a single longer day (20L:4D) or maintained in the 16L:8D photoperiod at ...

The diel activity of fourth-instar Culicoides furens (Poey) was studied in the laboratory by means of video recordings. Larvae in 0.5% agar under a photoperiod of 12:12 (L:D) h were observed under three nutritional states: starved 24 h before and during observation; fed (with nematodes) 24 h before, but starved ...

The effect of photoperiod on longevity of nondiapausing members of Anopheles crucians was evaluated in laboratory experiments. First-generation adults reared from field collections illustrated the same trends. Individuals reared and maintained under short photoperiod (either 8 h light:16 h dark or 11 h light:13 h dark) lived longer than did ...

Observations based on time-lapse video recordings were used to study behavior associated with egg cannibalism in fourth-instar Toxorhynchites amboinensis (Doleschall) and Tx. r. rutilus (Coquillett). Analysis indicated that, once triggered by finding of the first egg, larvae of both species engaged in a systematic search of the water surface in ...

Little red flying foxes (Pteropus scapulatus) are seasonal breeders: they mate in late spring/early summer, and young are born the following autumn. In captivity, males housed outdoors in a normal breeding colony in natural daylight showed a single cycle of testis growth and regression each year. During reproductive quiescence, testicular ...

Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status--the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic ...

The organisation of the thalamofugal visual projections to the forebrain has been determined in chick embryos by injecting retrograde tracers (true blue and either fluorogold or diamidino yellow) into the left or right hyperstriatum. The embryos were injected on day 19 of incubation and allowed to survive for a further ...

Almost exclusively, photoperiodic insects respond to a given photoperiod in one of two ways: a "long-day" response or a "short-day" response. Intermediate responses occur only at a very restricted range of photoperiods (often less than 30 min) and are generally population phenomena rather than intermediate responses of individuals. In contrast, ...

Empirical data suggest that reproductive photoresponsiveness occurs in some populations of mammals above 13 degrees of latitude, but may be absent in populations from 0 degrees to 10 degrees of latitude. The present experiments examined the degree to which the low amplitude of change in photoperiod in the tropics constrains ...

Echinostoma caproni eggs developed fully formed miracidia from hamster-source eggs in 9 days and from mouse-source eggs in 10 days under either light or dark conditions at 27 degrees C. Incubation of egg cultures under constant light resulted in miracidial hatching from hamster-source eggs in 11 days and from mouse-source ...

Our previous work has shown that constant light can prolong the life of hamsters with heart disease. Although we have seen this result several times, constant light was not protective in our most recent experiment. We undertook this study because we had changed some conditions. As in previous experiments, we ...

The electric fish, Eigenmannia, will smoothly shift the frequency of its electric organ discharge away from an interfering electric signal. This shift in frequency is called the jamming avoidance response (JAR). In this article, we analyze the behavioral development of the JAR and the anatomical development of structures critical for ...

Infanticide is a violent but successful reproductive strategy found in many mammals, particularly rodents. In male house mice (Mus domesticus and M. musculus), the act of ejaculation provides a reliable neural signal for timing the birth of their offspring. However, a unique chronobiological aspect of this phenomenon is the extraordinary ...

The visual projections from the thalamus to the Wulst of the chick forebrain are asymmetrically organized. The development of this asymmetry is dependent on light stimulation just prior to hatching, and it is present to a greater extent in males than in females. We have shown that administration of testosterone ...

The photoperiodic clock in quail (Coturnix coturnix japonica) is based upon a rhythm of photoinducibility (phi i) but the extent to which this rhythm is circadian remains unclear. Two types of experiment investigated this situation. In the first, gonadectomized quail were adapted to live in periods of darkness by training ...

Cutaneous electrogastrography (EGGc), the recording of gastric electrical activity from the cutaneous abdominal surface, still presents a series of difficulties connected with the interpretation of signals. In this study, the authors evaluated the reproducibility of electrogastrographic data over a period of time by making recordings on three consecutive days in ...

The effects of sodium vapor (SV), daylight fluorescent (DF), and incandescent (IN) light sources and the influence of the presence or absence of males on reproduction of female turkeys were evaluated. Hens under SV and DF lights consistently laid more eggs than those under IN lights. There were no significant ...

The laying performance of six genetic strains of turkeys, which have been bred and maintained at the Ohio Agricultural Research and Development Center, Wooster, OH, was compared under three laying house lighting regimens over a period of 3 yr. Light Treatment 1 (L1) consisted of 14 h of continuous light ...

The effect of photoperiod on wing length, body weight, and relationship between wing length and body weight was investigated in the mosquito species Anopheles quadrimaculatus. Individuals reared under a short photoperiod (8 h light: 16 h dark) had longer wings and larger weights than did those reared under a long ...

Onset of sexual maturation was determined in weanling male collared lemmings exposed to one of three experimental regimens of different photoperiods before and after weaning. Animals gestated in photoperiods of either 16 h light:8 h dark or 8 h light:16 h dark. Those from 16 h light:8 h dark were ...

The effect of light source and intensity on egg production, fertility, hatchability, egg weight, and shell quality in turkey hens was investigated. Turkey hens were exposed to either incandescent, high-pressure sodium vapor (HPSV), or daylight fluorescent (FL) lights at an intensity of 21.6 1x during the growth phase (after 8 ...

Mink are seasonal photosensitive breeders; testis activity is triggered when days have less than 10 h light. Increasing and decreasing plasma concentrations of prolactin induce the spring and autumn moults. In a 5 year experiment, males were maintained under short days (8 h light:16 h dark) at 13 degrees C ...

Broiler chicks obtained from a commercial hatchery were reared on litter in environmental chambers. The rearing temperature was 32 C initially, and reduced 2,8 C/wk until 24 C was reached. Water was available for ad libitum intake. The treatments began at 7 days in Trial 1 and at 8 days ...

The purpose of this study was to describe the luminal development of the murine eustachian tube and middle ear. Thirty specimens, aging from gestational day 11 to postnatal day 21, were investigated through the light microscopic observations. The present study also used digitizer, computer, and serially sectioned temporal bone specimens ...

Blackheaded buntings were exposed to constant dim light (approximately 2 lux) for 77 days and subsequently to 12:12 illumination, consisting of either dim light:complete darkness (dl:dk) (2:0 lux) or bright light:dim light (bl:dl) (10, 35, and 90 lux:2, 10, and 35 lux, respectively, with 180 degrees bl:dl transitions) for 2-3 ...

Two trials were conducted to determine whether light intensity levels during the prelay (light restriction) and the lay (egg production) periods influenced subsequent photoinduced reproductive performance of turkey breeder hens. The light intensity levels were 22 and 270 lx and each was provided during the prelay and lay periods in ...

A population of cloud forest mice (Peromyscus nudipes) at latitude 10 degrees N near Monteverde, Costa Rica, was sampled four times by live-trapping twice during the 7-8 month wet season and twice during the 4-5 month dry season in 1989 and 1990. Body weights were lower during the early part ...

We have measured the acoustic startle response (ASR) amplitude and latency in rats housed in a 12:12 light:dark (LD) cycle. The response amplitudes to eliciting stimuli (ES) of 110 dB or 120 dB (white noise) were significantly higher (nearly two-fold) during D than during L. Similar, but nonsignificant, trends were ...

Serum melatonin rhythm was studied in 6 human subjects experiencing short winter days resembling light/dark (LD) 8:16 h and in 6 subjects exposed at the same time to a long, LD 16:8 h skeleton photoperiod, with 3 h of bright light in the evening and again in the morning; 4 ...

This experiment was conducted in Ile-de-France adult rams to examine the target point of a 2-month light cycle regimen on seminiferous tubule functions, on intertubular compartment and on Leydig cell parameters. Eight rams were subjected to a 2-month light cycle regimen and were compared to sexually active or inactive rams. ...

Twenty-four potato (Solanum tuberosum L.) cultivars from different regions of the world were evaluated in terms of their responses to continuous light (24 h photoperiod) and to high temperature (30 C) in two separate experiments under controlled environments. In each experiment, a first evaluation of the cultivars was made at ...

For 68 years latitude has been identified as an important risk factor in the occurrence of multiple sclerosis (MS), but not satisfactory explanation has been offered for this relationship. Epidemiological studies of MS, however, have failed to take into account the degree of change in the amount of ambient light ...

Seasonal changes in daylength (photoperiod) modify the duration of nocturnal melatonin (MT) secretion in many vertebrates. In some cases the changes in MT act as chemical signals that trigger photoperiodic induction of breeding and other seasonal phenomena. It is unclear whether, and to what extent changes in daylength modify the ...

Immature cockerels were reared under constant light [24 h light (L):0 h dark (D)] or a 12L:12D photoperiod in order to evaluate the effect of constant light on immunoresponsiveness. At 10 wk of age males were immunized with SRBC, with reimmunization occurring either 3 or 8 wk later. Animals reared ...

Two trials were conducted to evaluate the reproductive performance of turkey hens to different light intensity during the lay period. In Trial 1 the hens were exposed to 16 h of light (L) and 8 h dark (D) per day (16L:8D) at 54, 108, or 216 lx and in Trial ...

The number of Toxorhynchites r. rutilus eggs occurring in 20 ground-level oviposition traps was monitored daily for 14 days in an area of coastal oak/palm hammock forest in Florida. Ten of these ovitraps (modified 2-liter plastic soda bottles) were placed in contact with tree trunks, the others at least 2 ...