375 research outputs found

    A Novel Multi-Aperture Based Sun Sensor Based on a Fast Multi-Point MEANSHIFT (FMMS) Algorithm

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    With the current increased widespread interest in the development and applications of micro/nanosatellites, it was found that we needed to design a small high accuracy satellite attitude determination system, because the star trackers widely used in large satellites are large and heavy, and therefore not suitable for installation on micro/nanosatellites. A Sun sensor + magnetometer is proven to be a better alternative, but the conventional sun sensor has low accuracy, and cannot meet the requirements of the attitude determination systems of micro/nanosatellites, so the development of a small high accuracy sun sensor with high reliability is very significant. This paper presents a multi-aperture based sun sensor, which is composed of a micro-electro-mechanical system (MEMS) mask with 36 apertures and an active pixels sensor (APS) CMOS placed below the mask at a certain distance. A novel fast multi-point MEANSHIFT (FMMS) algorithm is proposed to improve the accuracy and reliability, the two key performance features, of an APS sun sensor. When the sunlight illuminates the sensor, a sun spot array image is formed on the APS detector. Then the sun angles can be derived by analyzing the aperture image location on the detector via the FMMS algorithm. With this system, the centroid accuracy of the sun image can reach 0.01 pixels, without increasing the weight and power consumption, even when some missing apertures and bad pixels appear on the detector due to aging of the devices and operation in a harsh space environment, while the pointing accuracy of the single-aperture sun sensor using the conventional correlation algorithm is only 0.05 pixels

    Systematics and ecology of Naiadacarus nepenthicola, a new species of acaridae (Acari: Astigmata) inhabiting the pitchers of Nepenthes bicalcarata hook. f. in Brunei Darussalam

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    A new species, Naiadacarus nepenthicola, is described from adults and deutonymphs collected in Belait District, Brunei Darussalam, from the fluid-filled pitchers of Nepenthes bicalcarata Hook. f.. This constitutes the first record of a member of the family Acaridae inhabiting Nepenthes pitchers. It is quite probably that N. nepenthicola feeds on decomposing leaves that fall into the pitchers as well as on decomposing insects trapped by pitchers. Dispersal is accomplished through phoresy on Campanotus schmitzi Staercke, an ant that nests exclusively in the hollow tendrils of N. bicalcarata pitchers

    Chaos in the Classroom: Center Learning in a 1st Grade Setting

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    How can centers be utilized in a classroom so students have full control of what they are learning and when? Can centers be used effectively post-kindergarten? During student teaching in a first grade classroom in southeast Louisiana, two student teachers, their classroom mentor teacher, and the 1st grade students experienced center learning that integrated all areas of the curriculum and was utilized for 45 minutes each day. Students were expected to determine which center they needed to attend each day, which activity to complete, who to complete it with, where to put completed work, and how to successfully tidy up the center. The classroom teacher used this independent exploratory learning time to pull students in small groups to target their reading and comprehension skills. The purpose of this research was to determine which factors played an integral part of the success of center learning in a first grade classroom. The student teachers observed the 16 centers, interviewed the students and the teacher, took photos, and videoed center time. After analyzing the research, centers appeared to be organized in an effective manner, student learning was the primary goal, which enhanced students’ ability to enjoy learning in centers and also gain social skills through collaboration

    Sex and age differences in juvenile social priorities in female philopatric, nondespotic blue monkeys

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    Juveniles should choose social partners on the basis of both current and future utility. Where one sex is philopatric, one expects members of that sex to develop greater and sex-typical social integration with group-mates over the juvenile period. Where a partner's position in a dominance hierarchy is not associated with services it can provide, one would not expect juveniles to choose partners based on rank, nor sex differences in rank-based preferences. We tested these ideas on 39 wild juvenile (3.2–7.4 years) blue monkeys ( Cercopithecus mitis stuhlmanni), cercopithecines with strict female philopatry and muted hierarchies. We made focal animal observations over 6 months, and computed observed:expected amounts of proximity time, approaches and grooming given to various social partners. Overall, our results agree with the hypothesis that juvenile blue monkeys target social partners strategically. Spatial proximity, approaches and active grooming showed similar patterns regarding juvenile social preferences. Females were far more sociable than males, groomed more partners, reciprocated grooming more frequently, and preferred—while males avoided—infants as partners. Older juveniles (5–7 years) spent more time than younger juveniles (3–4 years) near others, and older females were especially attracted to infants. Close kin, especially mothers and less consistently adult sisters, were attractive to both male and female juveniles, regardless of age. Both sexes also preferred same-sex juveniles as social partners while avoiding opposite-sex peers. Juveniles of both sexes and ages generally neither preferred nor avoided nonmaternal adult females, but all juveniles avoided adult males. Partner's rank had no consistent effect on juveniles' preference, as expected for a species in which dominance plays a weak role. Juveniles' social preferences likely reflect both future and current benefits, including having tolerant adult kin to protect them against predators and conspecifics, same-sex play partners, and, for females, infants on which to practice mothering skills. Am. J. Primatol. 72:193–205, 2010. © 2009 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64898/1/20768_ftp.pd

    Behavioral responses to injury and death in wild Barbary macaques (Macaca sylvanus)

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    The wounding or death of a conspecific has been shown to elicit varied behavioral responses throughout thanatology. Recently, a number of reports have presented contentious evidence of epimeletic behavior towards the dying and dead among non-human animals, a behavioral trait previously considered uniquely human. Here, we report on the behavioral responses of Barbary macaques, a social, non-human primate, to the deaths of four group members (one high-ranking adult female, one high-ranking adult male, one juvenile male, and one female infant), all caused by road traffic accidents. Responses appeared to vary based on the nature of the death (protracted or instant) and the age class of the deceased. Responses included several behaviors with potential adaptive explanations or consequences. These included exploration, caretaking (guarding, carrying, and grooming), and proximity to wounded individuals or corpses, and immediate as well as longer-lasting distress behaviors from other group members following death, all of which have been reported in other non-human primate species. These observations add to a growing body of comparative evolutionary analysis of primate thanatology and help to highlight the multifaceted impacts of human-induced fatalities on an endangered and socially complex primate. © 2016, Japan Monkey Centre and Springer Japan

    Dietary Profile of Rhinopithecus bieti and Its Socioecological Implications

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    To enhance our understanding of dietary adaptations and socioecological correlates in colobines, we conducted a 20-mo study of a wild group of Rhinopithecus bieti (Yunnan snub-nosed monkeys) in the montane Samage Forest. This forest supports a patchwork of evergreen broadleaved, evergreen coniferous, and mixed deciduous broadleaved/coniferous forest assemblages with a total of 80 tree species in 23 families. The most common plant families by basal area are the predominantly evergreen Pinaceae and Fagaceae, comprising 69% of the total tree biomass. Previous work has shown that lichens formed a consistent component in the monkeys’ diet year-round (67%), seasonally complemented with fruits and young leaves. Our study showed that although the majority of the diet was provided by 6 plant genera (Acanthopanax, Sorbus, Acer, Fargesia, Pterocarya, and Cornus), the monkeys fed on 94 plant species and on 150 specific food items. The subjects expressed high selectivity for uncommon angiosperm tree species. The average number of plant species used per month was 16. Dietary diversity varied seasonally, being lowest during the winter and rising dramatically in the spring. The monkeys consumed bamboo shoots in the summer and bamboo leaves throughout the year. The monkeys also foraged on terrestrial herbs and mushrooms, dug up tubers, and consumed the flesh of a mammal (flying squirrel). We also provide a preliminary evaluation of feeding competition in Rhinopithecus bieti and find that the high selectivity for uncommon seasonal plant food items distributed in clumped patches might create the potential for food competition. The finding is corroborated by observations that the subjects occasionally depleted leafy food patches and stayed at a greater distance from neighboring conspecifics while feeding than while resting. Key findings of this work are that Yunnan snub-nosed monkeys have a much more species-rich plant diet than was previously believed and are probably subject to moderate feeding competition

    Pongamia seed cake as a valuable source of plant nutrients for sustainable agriculture

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    Pongamia, a multipurpose leguminous tree containing non-edible oil, grows widely in India. Oil extracted from the seeds of Pongamia is used as energy source as well as in tanneries while the cake (a byproduct after extracting oil) was found to be rich in all plant nutrients in general and nitrogen (4.28%) and sulfur (0.19%) in particular. Both nitrogen and sulfur were found to be deficient in 100 and 80%, respectively, in soil samples from farmers' fields in Powerguda village of Adilabad district, Andhra Pradesh, India. Use of Pongamia seed cake as a source of plant nutrients for maize, soyabean and cotton was found beneficial in participatory research and development trials on farmers' fields. Further, application of critically deficient micronutrients such as zinc and boron and secondary nutrient sulfur increased crop yields by 16.7 and 19% in soyabean and cotton, respectively. In addition, B:C ratios of 5.03, 1.81 and 2.04 were obtained for soyabean, maize and cotton, respectively, with use of cake as a source of N, however it needed higher initial investment
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