Social learning has important ecological and evolutionary consequences but the role of certain factors, such as social rank, neophobia (i.e., avoidance of novel stimuli), persistence, and task-reward ...association, remain less understood. We examined the role of these factors in social learning by captive coyotes (Canis latrans) via three studies. Study 1 involved individual animals and eliminated object neophobia by familiarizing the subjects to the testing apparatus prior to testing. Studies 2 and 3 used mated pairs to assess social rank, and included object neophobia, but differed in that study 3 decoupled the food reward from the testing apparatus (i.e., altered task-reward association). For all three studies, we compared performance between coyotes that received a demonstration from a conspecific to control animals with no demonstration prior to testing. Coyotes displayed social learning during study 1; coyotes with a demonstrator were faster and more successful at solving the puzzle box but did not necessarily use the same modality as that observed to be successful. In study 2, there was no difference in success between treatment groups but this is likely because only one coyote within each pair was successful so successful coyote results were masked by their unsuccessful mate. In study 3, there was no difference in success between treatment groups; only two coyotes, both dominant, hand-reared males with demonstrators were able to perform the task. However, coyotes with a demonstrator were less neophobic, measured as latency to approach the object, and more persistent, measured as time spent working on the apparatus. Social rank was the best predictor of neophobia and persistence and was also retained in the best model for time to eat inside the apparatus, a post-trial measurement of object neophobia. These results suggest coyotes are capable of social learning for novel tasks but social rank, neophobia, and persistence influence their social-learning capabilities. This study contributes to understanding the mechanisms underlying how animals gain information about their environment.
Social monogamy is a unique social system exhibited by only 3–5% of mammalian taxa; however, all wild canid species exhibit this social system. Despite the high prevalence of social monogamy among ...canids, little is known about how they form selective social attachment relationships among non-kin. Thus, we aimed to quantify monogamous behavior in a highly ubiquitous canid, the coyote (Canis latrans). We adapted the three-chambered partner preference test, which was originally developed for prairie voles (Microtus ochrogaster), to assess social preference in mated pairs of captive coyotes at the USDA Predator Research Facility. We quantified monogamy-related behaviors, such as time spent in spatial proximity to a pair-mate versus a stranger. Our behavioral ethogram also included visual seeking, olfactory investigations, ears down, scent marking, and affiliative behavior. Test subjects showed significantly greater affiliative behavior toward their partner than toward a stranger. However, there was extremely high variability both within and between coyote pairs across behavioral measures. These data suggest the need for larger sample sizes when working with species with high individual variability, as well as the need for species- and facility-specific modifications to this testing paradigm and/or ethogram to better adapt it from its laboratory and rodent-based origins.
•We quantified monogamous behavior in captive coyotes via a partner preference test.•Coyotes showed more affiliative behaviors toward their partner versus a stranger.•Individual variability within and between coyote pair-mates was extremely high.•Further adaptions are needed to optimize these social paradigms for coyotes.•These are the first steps in examining the biological basis of canid pair-bonding.
This study sought to determine the feasibility and antitumor efficacy of an intensified three-drug chronomodulated regimen with maximum delivery at 4:00 AM for fluorouracil (5-FU)-leucovorin (folinic ...acid FA) and at 4:00 PM for oxaliplatin (I-OHP).
Fifty patients with metastatic colorectal cancer were enrolled in the trial. The first treatment course consisted of daily administration of 5-FU (700 mg/m2/d), FA (300 mg/m2/d), and L-OHP (25 mg/m2/d) for 4 days with a multichannel programmable pump. Courses were repeated every 14 days, with 5-FU escalation by 100 mg/m2/d if toxicity was less than grade 2.
World Health Organization (WHO)-modified grade 3 or 4 diarrhea (40% of patients and 7% of courses) or stomatitis (28% of patients and 4% of courses) or grade 2 cumulative peripheral sensitive neuropathy (28% of patients) were dose-limiting. Median 5-FU and L-OHP dose-intensities (DIs), were increased by 32% and 18%, respectively, as compared with our previous 5 days on-16 days off schedule. The overall objective response rate was 48% (95% confidence limits CL, 34% to 62%), being 40% (24% to 57%) in 37 previously treated patients and 69% (48% to 90%) in 13 chemotherapy-naive patients. A 5-FU DI > 1,400 mg/m2/wk over four courses was associated with a near doubling of the response rate. Residual metastases were surgically removed in 13 patients (26%). Median progression-free survival and survival durations were 9.3 months (95% CL, 6.6 to 11.2) and 17.8 months (95% CL, 14.1 to 21.4), respectively.
This highly effective fully ambulatory outpatient regimen deserves further testing in randomized trials both in chemotherapy-naive patients and before surgery to remove metastases.
Performance of the CMS Event Builder Andre, J-M; Behrens, U; Branson, J ...
Journal of physics. Conference series,
10/2017, Letnik:
898, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The data acquisition system (DAQ) of the CMS experiment at the CERN Large Hadron Collider assembles events at a rate of 100 kHz, transporting event data at an aggregate throughput of O(100GB/s) to ...the high-level trigger farm. The DAQ architecture is based on state-of-the-art network technologies for the event building. For the data concentration, 10/40 Gbit/s Ethernet technologies are used together with a reduced TCP/IP protocol implemented in FPGA for a reliable transport between custom electronics and commercial computing hardware. A 56 Gbit/s Infiniband FDR Clos network has been chosen for the event builder. This paper presents the implementation and performance of the event-building system.
The fur of mammals serves many functions, including thermoregulation, camouflage or visual signaling to conspecifics. Fine-scale features of fur, such as hair morphology are often examined by ...researchers, especially in animals where pelage is of economic importance. Certain studies from this literature body show that males of many species appear to have thicker guard hair than females. Here, we examined this possibility in coyote (Canis latrans) and white tailed deer (Odocoileus virginianus) from captive populations in Utah and Georgia, USA. We used image analysis procedures to examine 402 guard hairs from 24 captive coyotes and 568 guard hairs from 29 captive deer, measuring the length and diameter of each hair. In both species, males had significantly thicker hairs than females; in coyotes, male hairs were 17% thicker, in deer, male hairs were 15% thicker. These differences are comparable to other species, where male hair is between 7%–20% thicker than those of females (in all species the average difference is 13%). Considering that there are hundreds of thousands of hairs on any given animal, this difference per unit hair could translate into considerable differences in overall pelt characteristics between sexes. The reason for this difference could relate to the sensitivity of mammalian hair to androgens, such as testosterone, which are more abundant in males of all species. Experimental studies and population surveys demonstrate that high levels of androgens stimulate body hair to grow thicker in diameter. Thus, the greater levels of testosterone in males would act to promote thicker hair. By this same mechanism, within any given collection of males, those with greater levels of androgens should also display greater hair thickness. While further research would be needed to verify this, results from this study nevertheless emphasize the knowledge gaps that yet remain in our understanding of the basic nature of mammalian fur.
In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and ...single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.
The hypothesis that light-induced circadian clock suppression exerts a promoting effect on liver carcinogenesis was investigated in rats.
Sixty-five male Wistar rats were given diethylnitrosamine ...(DEN, 10 mg/kg/day p.o.) for 6 weeks and were randomized into 3 groups. Rats from group 1 (N = 20) received DEN only. Rats from group 2 (N = 22) also received phenobarbital (pheno, 30 mg/rat/day p.o.) for 4 weeks as a promoting agent and rats from group 3 (N = 23) were exposed to continuous light. Three months after starting DEN treatment, urinary 6-sulfatoxymelatonin (αMT6s) excretion, a marker of circadian clock function, had lost its circadian rhythmicity in the LL group, with a 4-fold lower 24h mean than that found in the LDpheno and LD groups (8.0 ± 3.2
ng
ml
, 33.6 ± 3.1
ng
ml
and 34.3 ± 2.4
ng
ml
respectively; p from ANOVA < 0.001). Laparotomy was then performed. The proportion of rats with macroscopic nodules on liver surface was 72% (LD group), 89% (LDpheno group) and 95% (LL group) (p from
χ
2 = 0.1). Nodules were more numerous and larger both in the LL group and in the LDpheno one as compared to the LD group (p from
χ
2 < 0.05). All the rats died with hepatocellular carcinomas, with a median survival of 5 months, similar in all 3 groups. Light-induced circadian clock suppression exerted a promoting effect similar to that caused by phenobarbital in this model, yet through different effects on circadian system function.
A pair bond is a long-term social relationship between two unrelated individuals of the opposite sex that persists outside of the breeding season. The strength of a pair bond is often linked to ...behavioural and physiological components, such as behavioural synchrony and hormonal status, and can be measured across timescales, contexts and species. Pair mates that spend more time in proximity and that engage in the same activities are often more strongly bonded than pair mates that behave independently. Thus, the objectives of this study were to determine whether the amount of time that canid pair mates spend in proximity provides an index for the strength of their pair bond and whether pair bonds are dynamic or static across time and other factors. Coyotes exhibit pair-bonding behaviour in the form of territorial defence and biparental care and therefore make an excellent model for our objectives. We fitted captive coyote pair mates with proximity-tracking collars and collected faecal samples to quantify synchronous behaviour and hormonal status. We measured pair mate proximity across reproductive seasons (breeding versus nonbreeding), pair bond tenures (newly paired, 1–2 years paired, 5+ years paired) and times of day (dawn, day, dusk, night). We found that dusk was an important temporal window for quantifying pair mate proximity because dusk was the time when pair mate proximity significantly differed according to reproductive season or pair bond tenure. We detected marginally higher faecal progesterone levels in female coyotes during the breeding season, relative to the nonbreeding season, but we did not find differences across other hormone metabolites assessed. Female faecal progesterone metabolite levels were the only hormone significantly correlated with proximity behaviour outcomes. These results suggest that the amount of time that coyote pair mates spend in proximity can provide an index for the strength of their pair bond and that these pair bonds are dynamic and can be influenced by internal and external factors.
•Coyote pair mate proximity provided an index for the strength of pair bonds.•Coyote pair bonds were dynamic and were influenced by internal and external factors.•Proximity was greater at dusk in the breeding season than in the nonbreeding season.•Coyotes paired for 1–2 years exhibited the most proximity behaviour.•Higher female progesterone levels were associated with greater proximity at dusk.
Circadian rhythms in circulating leukocyte and lymphocyte counts persisted with halved amplitudes in constant light (LL) of 300 lx intensity for 8 wk, whereas circadian rhythms in body temperature, ...locomotor activity, and plasma catecholamines were completely suppressed. Subsequent exposure to constant darkness (DD) normalized all circadian rhythms within 2 wk. Rhythms in circulating T lymphocyte subsets were studied in LL or DD using double labeling with monoclonal antibodies and flow cytometry. Circadian rhythms were suppressed for leukocytes and lymphocytes but were maintained for both T helper cells (Th) and T cytotoxic cells (Ts) lymphocytes after 11 wk in LL. A group 24-h rhythm was only validated for total lymphocytes after 16 wk in LL. However, individual total, Th, and Ts lymphocytes maintained their usual respective phase relationships in each rat. The alteration of immune cell circulatory rhythms likely stemmed from a progressive loss of circadian synchronization among rats kept in LL. Conversely, after 11 or 16 wk in DD, leukocytes and lymphocyte subsets circadian rhythms were maintained. Thus catecholamines do not drive circulatory T cell rhythms. The loss of coupling between T lymphocyte rhythms and three major outputs of the circadian system further supports the hypothesis of an independent immunologic oscillator.
Endogenous circadian rhythms in body temperature and locomotor activity rhythms are suppressed in Sprague–Dawley rats exposed to prolonged continuous light, possibly as a result of a profound ...alteration of the melatonin secretion rhythm. The ability to restore circadian system function with either exogenous melatonin, or melatonin receptor agonist S20242 (
N-2-(7-methoxy napth-1-yl)ethyl propionamide), or 5-HT
1A receptor agonist, 8-hydroxy-2-(di-
n-propylamino)tetralin (8-OH-DPAT), was investigated under these conditions. Seven rats received a daily 6-h intravenous infusion of melatonin (0.01 mg kg
−1) for 10 days, which generates a nearly physiological circadian rhythm of urinary 6-sulfatoxy-melatonin, the main urinary metabolite of melatonin. Nevertheless, there was no effect on body temperature or locomotor activity rhythms. Then, 49 rats received daily subcutaneous melatonin (0.01, 1 or 5 mg kg
−1 day
−1), S20242 (1 or 5 mg kg
−1 day
−1) or 8-OH-DPAT (5 mg kg
−1 day
−1) for 30 days. The circadian rhythm in body temperature was restored by subcutaneous melatonin or by S20242 as a function of the dose or by 8-OH-DPAT. The effect started within the first 10 days of treatment and persisted for 1 to 3 weeks following the end of treatment in 8 of 10 rats receiving melatonin, in 9 of 11 rats treated with S20242 and in 1 of 4 rats treated with 8-OH-DPAT. Activity was less susceptible to entrainment than temperature with these drugs, since circadian rhythmicity was restored in only 2 of 6 rats treated with melatonin and in 1 of 4 rats treated with 8-OH-DPAT. These data demonstrate a specific action of subcutaneous melatonin, S20242 or 8-OH-DPAT on temperature rather than on activity rhythms. This differential effect on two major outputs of the suprachiasmatic nucleus further supports the existence of two independent oscillators in this hypothalamic circadian clock, which may be considered as separate pharmacological targets in the circadian system.
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