1,802 research outputs found

    Evidence of means–end behavior in Asian elephants (Elephas maximus)

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    The present study explores to what extent Asian elephants show “means–end” behavior. We used captive Asian elephants (N = 2) to conduct four variations of the Piagetian “support” problem, which involves a goal object that is out of reach, but rests on a support within reach. In the first condition, elephants were simultaneously presented with two identical trays serving as the “support”, with the bait on one tray and the other tray left empty. In the next two conditions, the bait was placed on one tray, while additional bait was placed beside the other tray. In the last condition, both trays contained bait, but one of the trays had a small gap which prevented the elephants from reaching the reward. Subjects were required to choose and pull either tray with their trunk and to obtain the bait (i.e. goal). Results showed that one elephant performed all of the support problems significantly above chance after several sessions, suggesting that the elephant was capable of understanding that pulling the tray was the “means” for achieving the “end” of obtaining the bait. This study showed that elephants show means–end behavior when subjected to a Piagetian “support” task, and indicates that such goal-directed behavior occurs in species other than primates

    Technique for increasing the output impedance of CMOS regulated cascode circuits

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    A technique is proposed for the design of a modified CMOS regulated cascode having an output impedance significantly greater than that of a conventional regulated cascode. Simulation results for an illustrative design, operating at 10µA from a 1V supply, show an increase in output resistance from 636MΩ and output bandwidth of 55kHz for a conventional circuit to 6.68GΩ and 389kHz, respectively, for the proposed design

    Disgust sensitivity is not associated with health in a rural Bangladeshi sample.

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    Disgust can be considered a psychological arm of the immune system that acts to prevent exposure to infectious agents. High disgust sensitivity is associated with greater behavioral avoidance of disease vectors and thus may reduce infection risk. A cross-sectional survey in rural Bangladesh provided no strong support for this hypothesis. In many species, the expression of pathogen- and predator-avoidance mechanisms is contingent on early life exposure to predators and pathogens. Using childhood health data collected in the 1990s, we examined if adults with more infectious diseases in childhood showed greater adult disgust sensitivity: no support for this association was found. Explanations for these null finding and possible directions for future research are discussed

    Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013

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    Abstract Background Despite its Gallic name, the French Bulldog is a breed of both British and French origin that was first recognised by The Kennel Club in 1906. The French Bulldog has demonstrated recent rapid rises in Kennel Club registrations and is now (2017) the second most commonly registered pedigree breed in the UK. However, the breed has been reported to be predisposed to several disorders including ocular, respiratory, neurological and dermatological problems. The VetCompass™ Programme collates de-identified clinical data from primary-care veterinary practices in the UK for epidemiological research. Using VetCompass™ clinical data, this study aimed to characterise the demography and common disorders of the general population of French Bulldogs under veterinary care in the UK. Results French Bulldogs comprised 2228 (0.49%) of 445,557 study dogs under veterinary care during 2013. Annual proportional birth rates showed that the proportional ownership of French Bulldog puppies rose steeply from 0.02% of the annual birth cohort attending VetCompass™ practices in 2003 to 1.46% in 2013. The median age of the French Bulldogs overall was 1.3 years (IQR 0.6–2.5, range 0.0–13.0). The most common colours of French Bulldogs were brindle (solid or main) (32.36%) and fawn (solid or main) (29.9%). Of the 2228 French Bulldogs under veterinary care during 2013, 1612 (72.4%) had at least one disorder recorded. The most prevalent fine-level precision disorders recorded were otitis externa (14.0%, 95% CI: 12.6–15.5), diarrhoea (7.5%, 95% CI: 6.4–8.7), conjunctivitis (3.2%, 95% CI: 2.5–4.0), nails overlong (3.1%, 95% CI% 2.4–3.9) and skin fold dermatitis (3.0%, 95% CI% 2.3–3.8). The most prevalent disorder groups were cutaneous (17.9%, 95% CI: 16.3–19.6), enteropathy (16.7%, 95% CI: 15.2–18.3), aural (16.3%, 95% CI: 14.8–17.9), upper respiratory tract (12.7%, 95% CI: 11.3–14.1) and ophthalmological (10.5%, 95% CI: 9.3–11.9). Conclusions Ownership of French Bulldogs in the UK is rising steeply. This means that the disorder profiles reported in this study reflect a current young UK population and are likely to shift as this cohort ages. Otitis externa, diarrhoea and conjunctivitis were the most common disorders in French Bulldogs. Identification of health priorities based on VetCompass™ data can support evidence–based reforms to improve health and welfare within the breed

    Canine pseudopregnancy: an evaluation of prevalence and current treatment protocols in the UK

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    Background: There is a dearth of literature on pseudopregnancy in the bitch, with only a few treatment-based studies published since the 1990s. Pseudopregnancy may be under-recognised in bitches and may account for a proportion of behavioural cases seen in veterinary practices including aggression. Little is known about commonly used treatments for overtly pseudopregnant bitches and it is possible that current regimes may not be prescribed for a sufficient duration to control any clinical signs including, physical and behavioural changes. To investigate current trends in diagnosis and treatment of canine pseudopregnancy, a postal survey was sent to 2000 randomly selected veterinary surgeons in UK veterinary practices. The questionnaire queried how often vets recognise cases of pseudopregnancy in spayed and entire bitches, which physical or behavioural signs are commonly recognised for diagnosis, and which management or treatment protocols are used. Results: The response rate was 19.8% (397/2000). Ninety-six percent of veterinary surgeons reported seeing pseudopregnant bitches showing behavioural changes without any physical changes within the last 12 months. Of those behavioural changes, collecting and mothering objects was the most frequently reported behavioural sign (96%). Ninety-seven percent of vets had seen aggression in pseudopregnant bitches. Nevertheless, only 52% of vets routinely asked owners about behavioural changes during consultations. Forty-nine percent of respondents reported seeing pseudopregnancy in spayed bitches. The most commonly reported physical sign was enlarged mammary glands and/or milk production (89%). Treatment options varied (surgical, medical or none) and depended on duration and severity of physical and behavioural signs, owners’ preference, cost, concurrent disease, drug availability and previous history. Conclusions: This is the largest epidemiological study of canine pseudopregnancy in the UK. The prevalence and severity of clinical signs in dogs with pseudopregnancy are variable and possibly under-estimated. Dogs with overt pseudopregnancy experience diverse physical and behavioural changes and information on standard treatment protocols are lacking. Although, progress on our understanding of diagnosis and treatment of pseudopregnancy in spayed and entire bitches has been made, further studies are warranted

    Evidence for the return of subducted continental crust

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    Author Posting. © Nature Publishing Group, 2007. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 448 (2007): 684-687, doi:10.1038/nature06048.Substantial quantities of terrigenous sediments are known to enter the mantle at subduction zones, but little is known about their fate in the mantle. Subducted sediment may be entrained in buoyantly upwelling plumes and returned to the earth’s surface at hotspots, but the proportion of recycled sediment in the mantle is small and clear examples of recycled sediment in hotspot lavas are rare. We report here remarkably enriched 87Sr/86Sr and 143Nd/144Nd isotope signatures (up to 0.720830 and 0.512285, respectively) in Samoan lavas from three dredge locations on the underwater flanks of Savai’i island, Western Samoa. The submarine Savai’i lavas represent the most extreme 87Sr/86Sr isotope compositions reported for ocean island basalts (OIBs) to date. The data are consistent with the presence of a recycled sediment component (with a composition similar to upper continental crust, or UCC) in the Samoan mantle. Trace element data show similar affinities with UCC—including exceptionally low Ce/Pb and Nb/U ratios—that complement the enriched 87Sr/86Sr and 143Nd/144Nd isotope signatures. The geochemical evidence from the new Samoan lavas radically redefines the composition of the EM2 (enriched mantle 2) mantle endmember, and points to the presence of an ancient recycled UCC component in the Samoan plume

    Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.

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    Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses

    An experimental study of sexual function improving effect of Myristica fragrans Houtt. (nutmeg)

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    BACKGROUND: Myristica fragrans Houtt. (nutmeg) has been mentioned in Unani medicine to be of value in the management of male sexual disorders. The present study was undertaken to evaluate the aphrodisiac effect of 50% ethanolic extract of nutmeg along with its likely adverse effects and acute toxicity using various animal models. METHODS: The suspension of the extract was administered (100, 250 and 500 mg/kg, p.o.) to different groups of male rats daily for seven days. The female rats involved in mating were made receptive by hormonal treatment. The general mating behaviour, libido and potency were studied and compared with the standard reference drug sildenafil citrate. Likely adverse effects and acute toxicity of the extract were also evaluated. RESULTS: Oral administration of the extract at the dose of 500 mg/kg, produced significant augmentation of sexual activity in male rats. It significantly increased the Mounting Frequency, Intromission Frequency, Intromission Latency and caused significant reduction in the Mounting Latency and Post Ejaculatory Interval. It also significantly increased Mounting Frequency with penile anaesthetisation as well as Erections, Quick Flips, Long Flips and the aggregate of penile reflexes with penile stimulation. The extract was also observed to be devoid of any adverse effects and acute toxicity. CONCLUSION: The resultant significant and sustained increase in the sexual activity of normal male rats without any conspicuous adverse effects indicates that the 50% ethanolic extract of nutmeg possesses aphrodisiac activity, increasing both libido and potency, which might be attributed to its nervous stimulating property. The present study thus provides a scientific rationale for the traditional use of nutmeg in the management of male sexual disorders

    Insightful Problem Solving in an Asian Elephant

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    The “aha” moment or the sudden arrival of the solution to a problem is a common human experience. Spontaneous problem solving without evident trial and error behavior in humans and other animals has been referred to as insight. Surprisingly, elephants, thought to be highly intelligent, have failed to exhibit insightful problem solving in previous cognitive studies. We tested whether three Asian elephants (Elephas maximus) would use sticks or other objects to obtain food items placed out-of-reach and overhead. Without prior trial and error behavior, a 7-year-old male Asian elephant showed spontaneous problem solving by moving a large plastic cube, on which he then stood, to acquire the food. In further testing he showed behavioral flexibility, using this technique to reach other items and retrieving the cube from various locations to use as a tool to acquire food. In the cube's absence, he generalized this tool utilization technique to other objects and, when given smaller objects, stacked them in an attempt to reach the food. The elephant's overall behavior was consistent with the definition of insightful problem solving. Previous failures to demonstrate this ability in elephants may have resulted not from a lack of cognitive ability but from the presentation of tasks requiring trunk-held sticks as potential tools, thereby interfering with the trunk's use as a sensory organ to locate the targeted food
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