3,117 research outputs found
Eine evolutionsbiologische Perspektive der menschlichen Kognition: Die Rolle der gemeinschaftlichen Jungenaufzucht
Opposite effects of male and female helpers on social tolerance and proactive prosociality in callitrichid family groups
Across a broad variety of primate species (including lemurs, New World monkeys, Old World monkeys, and apes), proactive prosociality and social tolerance are linked to allomaternal care, reaching the highest levels in the cooperatively breeding callitrichid monkeys and humans. However, considerable variation exists within callitrichids, and the aim of this study was to identify factors that explain this variation. Male and female callitrichids pursue different reproductive strategies, leading males to play a more prominent role in allomothering. We thus hypothesised that prosociality and tolerance may be affected by group composition and sex differences. We analysed social tolerance and proactive prosociality data in 49 common marmosets and found that the number of female helpers in a group was negatively correlated with group-level prosociality and tolerance. At the individual level, rearing experience or age enhanced prosociality in male, but not in female helpers. These findings are consistent with the more ambivalent role of female helpers in infant rearing. Adding data from 5 cotton-top and 5 lion tamarins strengthened this pattern. The same factor which explains variation in prosociality and tolerance across primate species, i.e. allomaternal care, is therefore also linked to variation within common marmosets, and presumably callitrichid monkeys in general
Ambulatory scintigraphic assessment of transient changes in left ventricular function: a new method for detection of silent myocardial ischaemia
Demonstration of ischaemic left ventricular dysfunction in the absence of chest pain should provide important confirmation of silent myocardial ischaemia in patients with asymptomatic ST segment changes. For this purpose, a new portable scintillation probe (VEST) similar to a miniaturized nuclear stethoscope combined with a Hotter ECG was evaluated. After standard equilibrium radionuclide angiocardiography with technetium-99m labelled red blood cells, the VEST was positioned under gamma-camera control and data were recorded from 1-12 h in 61 unselected patients. Ejection fraction (LVEF), relative changes in volumes, heart rate and ST segment changes were determined. Reproducibility of LVEF at rest (r = 0.91; variability 3.8 ± 3%, N = 19) and during exercise (r = 0.98; variability 3.2 ± 2%, N = 19) was good. In 15 asymptomatic exercise tests four different patterns of LVEF and ST segment responses were identified: (1) decrease in LVEF followed by significant ST depression (five times); (2) ST depression followed by decrease in LVEF (three times); (3) decrease in LVEF without significant ST changes (three times); and (4) ST depression without significant LVEF change (four times). In this still small series, patterns (1) to (3) corresponded to patients with documented coronary artery disease, which was not the case for pattern (4). For detection of silent ischaemia at rest, a decrease in LVEF of >5% lasting for >1 min was defined as ischaemic LV dysfunction. Using this definition, four spontaneous episodes of silent LV dysfunction could be demonstrated in two of three CCU patients with unstable angina during 160-680 min of data recordings without simultaneous ST changes. Based on this initial experience, we conclude that VEST is a reproducible method to detect transient global LV dysfunction and will be useful to confirm silent ischaemia in otherwise uncertain ST segment change
Can captive orangutans (Pongo pygmaeus abelii) be coaxed into cumulative build-up of techniques?
While striking cultural variation in behavior from one site to another has been described in chimpanzees and orangutans, cumulative culture might be unique to humans. Captive chimpanzees were recently found to be rather conservative, sticking to the technique they had mastered, even after more effective alternatives were demonstrated. Behavioral flexibility in problem solving, in the sense of acquiring new solutions after having learned another one earlier, is a vital prerequisite for cumulative build-up of
techniques. Here, we experimentally investigate whether captive orangutans show such flexibility, and if so, whether they show techniques that cumulatively build up (ratchet) on previous ones after conditions of the task are changed. We provided nine Sumatran orangutans (Pongo pygmaeus abelii) with two types of transparent tubes partly filled with syrup, along with potential tools such as sticks, twigs, wood wool and paper. In the first phase, the orangutans could reach inside the tubes with their hands (Regular Condition), but in the following phase, tubes had been made too narrow for their hands to fit in (Restricted Condition 1), or in addition the setup lacked their favorite materials (Restricted Condition 2). The orangutans showed high behavioral flexibility, applying nine different techniques under the regular condition in total. Individuals abandoned preferred techniques and switched to different techniques under restricted conditions when this was advantageous. We show for two of these techniques how they cumulatively built up on earlier ones. This suggests that the near-absence of cumulative culture in wild orangutans is not due to a lack of flexibility when existing solutions to tasks are made impossible
Cardiac evaluation of candidates for kidney transplantation: value of exercise radionuclide angiocardiography
In view of the high incidence and mortality of coronary artery disease (CAD) in patients with kidney transplantation, a systematic cardiac evaluation was prospectively performed in 103 uraemic patients eligible for transplantation. After clinical examination, 28 patients with symptoms of CAD or diabetes mellitus were referred directly for coronary angiography, whereas the remaining 75 patients had rest and exercise radionuclide angiocardiography for evaluation of possible asymptomatic CAD. Among them, left ventricular ejection fraction was below 40% at rest or fell during exercise by at least 5 EF% in 12 patients; coronary angiography in nine showed CAD in four and hypertensive heart disease in five. In the remaining 63 (of 75) patients without severe resting left ventricular dysfunction or exercise ischaemia, the follow-up of 28 ±7 months revealed no clinical manifestation of CAD. Overall incidence of CAD in symptomatic and asymptomatic patients during a follow-up of 27 months after cardiac evaluation was 20 and 25% in non-diabetic and diabetic candidates for kidney transplantation, respectively (P = n.s.). Thus, clinical examination combined with exercise radionuclide angiocardiography in patients without signs or symptoms of heart disease had a high predictive accuracy for presence or absence of late manifestations of CAD. Exercise radionuclide angiocardiography is therefore a useful method for screening kidney transplantation candidates for asymptomatic CA
Studi Komparasi Pemahaman Konsep Sistem Pernapasan Manusia Melalui Penerapan Pembelajaran Konstruktivisme Tipe Novick Dipadu Concept Map Dan Ceramah Bervariasi
This research is aim to find out the different comprehension of human respiration system concept in the Novick type of constructivism learning with concept map and the varied lecturing learning. This study was a quasi-experimental research using Post-test Only With Nonequivalent Groups research design. The sampling technique used was Cluster Sampling one. The populations of this research were all of 11th degree students of science at SMA Negeri 2 Karanganyar in academic year 2012/2013. The samples of this research were the students of 11th Imersi I as experiment group and 11th Imersi II as control group. Technique of collecting data used was a multiple choice test with reasoning, essay test, and observation sheet. The hypothesis testing was carried out using t-test. The conclusion of research that there isn\u27t different comprehension of human respiratory system concept between the Novick type of constructivism learning with concept map and the varied lecturing learning
A convergent interaction engine: vocal communication among marmoset monkeys
To understand the primate origins of the human interaction engine, it is worthwhile to focus not only on great apes but also on callitrichid monkeys (marmosets and tamarins). Like humans, but unlike great apes, callitrichids are cooperative breeders, and thus habitually engage in coordinated joint actions, for instance when an infant is handed over from one group member to another. We first explore the hypothesis that these habitual cooperative interactions, the marmoset interactional ethology, are supported by the same key elements as found in the human interaction engine: mutual gaze (during joint action), turn-taking, volubility, as well as group-wide prosociality and trust. Marmosets show clear evidence of these features. We next examine the prediction that, if such an interaction engine can indeed give rise to more flexible communication, callitrichids may also possess elaborate communicative skills. A review of marmoset vocal communication confirms unusual abilities in these small primates: high volubility and large vocal repertoires, vocal learning and babbling in immatures, and voluntary usage and control. We end by discussing how the adoption of cooperative breeding during human evolution may have catalysed language evolution by adding these convergent consequences to the great ape-like cognitive system of our hominin ancestors.
This article is part of the theme issue ‘Revisiting the human ‘interaction engine’: comparative approaches to social action coordination’
The Wnt pathway controls cell death engulfment, spindle orientation, and migration through CED-10/Rac
Wnt signalling pathways have extremely diverse functions in animals, including induction of cell fates or tumours, guidance of cell movements during gastrulation, and the induction of cell polarity. Wnt can induce polar changes in cellular morphology by a remodelling of the cytoskeleton. However, how activation of the Frizzled receptor induces cytoskeleton rearrangement is not well understood. We show, by an in depth 4-D microscopy analysis, that the Caenorhabditis elegans Wnt pathway signals to CED-10/Rac via two separate branches to regulate modulation of the cytoskeleton in different cellular situations. Apoptotic cell clearance and migration of the distal tip cell require the MOM-5/Fz receptor, GSK-3 kinase, and APC/APR-1, which activate the CED-2/5/12 branch of the engulfment machinery. MOM-5 (Frizzled) thus can function as an engulfment receptor in C. elegans. Our epistatic analyses also suggest that the two partially redundant signalling pathways defined earlier for engulfment may act in a single pathway in early embryos. By contrast, rearrangement of mitotic spindles requires the MOM-5/Fz receptor, GSK-3 kinase, and beta-catenins, but not the downstream factors LIT-1/NLK or POP-1/Tcf. Taken together, our results indicate that in multiple developmental processes, CED-10/Rac can link polar signals mediated by the Wnt pathway to rearrangements of the cytoskeleton
Review of \u3ci\u3eUrochloa\u3c/i\u3e Breeder’s Toolbox with the Theory of Change and Stage Gate System Approach
Livestock production in the global south is at crossroads as there is a demand to increase Animal Source Foods to address hunger and pressure to lighten the environmental footprint often associated with livestock production. To satisfy both needs, the use of technologies that improve animal performance, while reducing land use and net Greenhouse Gas emissions produced by animals is essential. One of such technologies are Urochloa forage grasses.
Urochloa forage grasses are well known for their rusticity and their ability to grow in soils of low fertility and high aluminum content. These characteristics allow Urochloa to grow in areas temporally or spatially less suitable for crop production, but also have made ruminants production profitable in areas that would not be otherwise. However, productivity and sustainability of ruminant production in these areas is likely to fall within the next decade due to climate change unless action is taken.
Despite these known benefits of Urochloa forage species, breeding programs have long delayed initiation due to apomixes and differences in ploidy. In the mid-1980s, the development of suitable sexual germplasm allowed crossings, and therefore favoured the emergence of breeding programs. In recent decades, several advances in biology, molecular biology, phenotyping, population genetics, genomics and transcriptomics have generated a plethora of information that ought to be integrated for its use in a single breeding toolbox. We use the Theory of Change and Stage-Gate systems approach to review these advances in research and the utility of the current and future available tools. Further, we address the remaining lack of information, thus bridging the knowledge gap and enabling us to maximize the genetic gain in the different Urochloa breeding programs. In this way, we identify breeding bottlenecks and help to pinpoint priorities for Urochloa research and development
A First Look at Rotation in Inactive Late-Type M Dwarfs
We have examined the relationship between rotation and activity in 14
late-type (M6-M7) M dwarfs, using high resolution spectra taken at the W.M.
Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey.
Most were selected to be inactive at a spectral type where strong H-alpha
emission is quite common. We used the cross-correlation technique to quantify
the rotational broadening; six of the stars in our sample have vsini > 3.5
km/s. Our most significant and perplexing result is that three of these stars
do not exhibit H-alpha emission, despite rotating at velocities where previous
work has observed strong levels of magnetic field and stellar activity. Our
results suggest that rotation and activity in late-type M dwarfs may not always
be linked, and open several additional possibilities including a
rotationally-dependent activity threshold, or a possible dependence on stellar
parameters of the Rossby number at which magnetic/activity "saturation" takes
place in fully convective stars.Comment: 8 pages, 4 figures, accepted for publication in Ap
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