190 research outputs found

    Communicating Phylogeny: Evolutionary Tree Diagrams in Museums

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    Tree of life diagrams are graphic representations of phylogeny—the evolutionary history and relationships of lineages—and as such these graphics have the potential to convey key evolutionary ideas and principles to a variety of audiences. Museums play a significant role in teaching about evolution to the public, and tree graphics form a common element in many exhibits even though little is known about their impact on visitor understanding. How phylogenies are depicted and used in informal science settings impacts their accessibility and effectiveness in communicating about evolution to visitors. In this paper, we summarize the analysis of 185 tree of life graphics collected from museum exhibits at 52 institutions and highlight some potential implications of how trees are presented that may support or hinder visitors’ understanding about evolution. While further work is needed, existing learning research suggests that common elements among the diversity of museum trees such as the inclusion of anagenesis and absence of time and shared characters might represent potential barriers to visitor understanding

    Visualizing sound emission of elephant vocalizations: evidence for two rumble production types

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    Recent comparative data reveal that formant frequencies are cues to body size in animals, due to a close relationship between formant frequency spacing, vocal tract length and overall body size. Accordingly, intriguing morphological adaptations to elongate the vocal tract in order to lower formants occur in several species, with the size exaggeration hypothesis being proposed to justify most of these observations. While the elephant trunk is strongly implicated to account for the low formants of elephant rumbles, it is unknown whether elephants emit these vocalizations exclusively through the trunk, or whether the mouth is also involved in rumble production. In this study we used a sound visualization method (an acoustic camera) to record rumbles of five captive African elephants during spatial separation and subsequent bonding situations. Our results showed that the female elephants in our analysis produced two distinct types of rumble vocalizations based on vocal path differences: a nasally- and an orally-emitted rumble. Interestingly, nasal rumbles predominated during contact calling, whereas oral rumbles were mainly produced in bonding situations. In addition, nasal and oral rumbles varied considerably in their acoustic structure. In particular, the values of the first two formants reflected the estimated lengths of the vocal paths, corresponding to a vocal tract length of around 2 meters for nasal, and around 0.7 meters for oral rumbles. These results suggest that African elephants may be switching vocal paths to actively vary vocal tract length (with considerable variation in formants) according to context, and call for further research investigating the function of formant modulation in elephant vocalizations. Furthermore, by confirming the use of the elephant trunk in long distance rumble production, our findings provide an explanation for the extremely low formants in these calls, and may also indicate that formant lowering functions to increase call propagation distances in this species'

    Nipple aspiration and ductal lavage in women with a germline BRCA1 or BRCA2 mutation

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    INTRODUCTION: The aim of this study was to collect serial samples of nipple aspirate (NA) and ductal lavage (DL) fluid from women with germline BRCA1/2 mutations in order to create a biorepository for use in identifying biomarkers of breast cancer risk. METHODS: Between March 2003 and February 2005, 52 women with germline BRCA1 or BRCA2 mutations (median age 43 years, range 27 to 65 years) were scheduled for six-monthly NA, DL and venesection. DL was attempted for all NA fluid-yielding (FY) and any non-FY ducts that could be located at each visit. RESULTS: Twenty-seven (52%) women were postmenopausal, predominantly (19/27) from risk reducing bilateral salpingo-oophorectomy (BSO). FY ducts were identified in 60% of all women, 76% of premenopausal women versus 44% of postmenopausal (P = 0.026). Eighty-five percent of women had successful DL. Success was most likely in women with FY ducts (FY 94% versus non-FY 71% (P = 0.049). DL samples were more likely to be cellular if collected from FY ducts (FY 68% versus non-FY 43%; P = 0.037). Total cell counts were associated with FY status (FY median cell count 30,996, range 0 to >1,000,000 versus non-FY median cell count 0, range 0 to 173,577; P = 0.002). Four women (8%) had ducts with severe atypia with or without additional ducts with mild epithelial atypia; seven others had ducts with mild atypia alone (11/52 (21%) in total). Median total cell count was greater from ducts with atypia (105,870, range 1920 to >1,000,000) than those with no atypia (174, 0 to >1,000,000; P ≤ 0.001). CONCLUSION: It is feasible to collect serial NA and DL samples from women at high genetic risk of breast cancer, and we are creating a unique, prospective collection of ductal samples that have the potential to be used for discovery of biomarkers of breast cancer risk and evaluate the ongoing effects of risk reducing BSO. DL cellular atypia was not predictive of a current breast cancer and longer follow up is needed to determine whether atypia is an additional marker of future breast cancer risk in this population already at high genetic risk of breast cancer

    Glycans as receptors for influenza pathogenesis

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    Influenza A viruses, members of the Orthomyxoviridae family, are responsible for annual seasonal influenza epidemics and occasional global pandemics. The binding of viral coat glycoprotein hemagglutinin (HA) to sialylated glycan receptors on host epithelial cells is the critical initial step in the infection and transmission of these viruses. Scientists believe that a switch in the binding specificity of HA from Neu5Acα2-3Gal linked (α2-3) to Neu5Acα2-6Gal linked (α2-6) glycans is essential for the crossover of the viruses from avian to human hosts. However, studies have shown that the classification of glycan binding preference of HA based on sialic acid linkage alone is insufficient to establish a correlation between receptor specificity of HA and the efficient transmission of influenza A viruses. A recent study reported extensive diversity in the structure and composition of α2-6 glycans (which goes beyond the sialic acid linkage) in human upper respiratory epithelia and identified different glycan structural topologies. Biochemical examination of the multivalent HA binding to these diverse sialylated glycan structures also demonstrated that high affinity binding of HA to α2-6 glycans with a characteristic umbrella-like structural topology is critical for efficient human adaptation and human-human transmission of influenza A viruses. This review summarizes studies which suggest a new paradigm for understanding the role of the structure of sialylated glycan receptors in influenza virus pathogenesis.National Institute of General Medical Sciences (U.S.) (Glue Grant U54 GM62116)National Institutes of Health (U.S.) (Grant GM57073)Singapore-MIT Alliance for Research and Technolog

    The evolution of acoustic size exaggeration in terrestrial mammals

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    Recent studies have revealed that some mammals possess adaptations that enable them to produce vocal signals with much lower fundamental frequency (F0) and formant frequency spacing (ΔF) than expected for their size. Although these adaptations are assumed to reflect selection pressures for males to lower frequency components and exaggerate body size in reproductive contexts, this hypothesis has not been tested across a broad range of species. Here we show that male terrestrial mammals produce vocal signals with lower ΔF (but not F0) than expected for their size in mating systems with greater sexual size dimorphism. We also reveal that males produce calls with higher than expected F0 and ΔF in species with increased sperm competition. This investigation confirms that sexual selection favours the use of ΔF as an acoustic size exaggerator, and supports the notion of an evolutionary trade-off between pre-copulatory signalling displays and sperm production

    Prion Shedding from Olfactory Neurons into Nasal Secretions

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    This study investigated the role of prion infection of the olfactory mucosa in the shedding of prion infectivity into nasal secretions. Prion infection with the HY strain of the transmissible mink encephalopathy (TME) agent resulted in a prominent infection of the olfactory bulb and the olfactory sensory epithelium including the olfactory receptor neurons (ORNs) and vomeronasal receptor neurons (VRNs), whose axons comprise the two olfactory cranial nerves. A distinct glycoform of the disease-specific isoform of the prion protein, PrPSc, was found in the olfactory mucosa compared to the olfactory bulb, but the total amount of HY TME infectivity in the nasal turbinates was within 100-fold of the titer in the olfactory bulb. PrPSc co-localized with olfactory marker protein in the soma and dendrites of ORNs and VRNs and also with adenylyl cyclase III, which is present in the sensory cilia of ORNs that project into the lumen of the nasal airway. Nasal lavages from HY TME-infected hamsters contained prion titers as high as 103.9 median lethal doses per ml, which would be up to 500-fold more infectious in undiluted nasal fluids. These findings were confirmed using the rapid PrPSc amplification QuIC assay, indicating that nasal swabs have the potential to be used for prion diagnostics. These studies demonstrate that prion infection in the olfactory epithelium is likely due to retrograde spread from the olfactory bulb along the olfactory and vomeronasal axons to the soma, dendrites, and cilia of these peripheral neurons. Since prions can replicate to high levels in neurons, we propose that ORNs can release prion infectivity into nasal fluids. The continual turnover and replacement of mature ORNs throughout the adult lifespan may also contribute to prion shedding from the nasal passage and could play a role in transmission of natural prion diseases in domestic and free-ranging ruminants

    Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae)

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    The hylid tribe Cophomantini is a diverse clade of Neotropical treefrogs composed of the genera Aplastodiscus, Boana, Bokermannohyla, Hyloscirtus, and Myersiohyla. The phylogenetic relationships of Cophomantini have been comprehensively reviewed in the literature, providing a suitable framework for the study of chromosome evolution. Employing different banding techniques, we studied the chromosomes of 25 species of Boana and 3 of Hyloscirtus; thus providing, for the first time, data for Hyloscirtus and for 15 species of Boana. Most species showed karyotypes with 2n = 2x = 24 chromosomes; some species of the B. albopunctata group have 2n = 2x = 22, and H. alytolylax has 2n = 2x = 20. Karyotypes are all bi-armed in most species presented, with the exception of H. larinopygion (FN = 46) and H. alytolylax (FN = 38), with karyotypes that have a single pair of small telocentric chromosomes. In most species of Boana, NORs are observed in a single pair of chromosomes, mostly in the small chromosomes, although in some species of the B. albopunctata, B. pulchella, and B. semilineata groups, this marker occurs on the larger pairs 8, 1, and 7, respectively. In Hyloscirtus, NOR position differs in the three studied species: H. alytolylax (4p), H. palmeri (4q), and H. larinopygion (1p). Heterochromatin is a variable marker that could provide valuable evidence, but it would be necesserary to understand the molecular composition of the C-bands that are observed in different species in order to test its putative homology. In H. alytolylax, a centromeric DAPI+ band was observed on one homologue of chromosome pair 2. The band was present in males but absent in females, providing evidence for an XX/XY sex determining system in this species. We review and discuss the importance of the different chromosome markers (NOR position, C-bands, and DAPI/CMA3 patterns) for their impact on the taxonomy and karyotype evolution in Cophomantini

    Structure and dynamics of the shark assemblage off recife, northeastern Brazil

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    Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.State Government of Pernambuco, Brazil; Fundacao para a Ciencia e Tecnologia, Portugal [SFRH/BD/37065/2007]info:eu-repo/semantics/publishedVersio

    Kombinasi Format Factory, U-lead dan Microsoft Office Powerpoint dalam Upaya Meningkatkan Kualitas Media Pembelajaran

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    Peserta didik mempunyai gaya belajar yang berbeda-beda. Gaya belajar tersebut meliputi auditori, visual dan kinestetik (VAK). Seorang guru harus mampu memenuhi kebutuhan masing-masing gaya belajar peserta didik tersebut. Salah satu cara yang dapat dilakukan adalah dengan menggunakan media pembelajaran berbasis VAK. Media pembelajaran berbasis VAK dapat dipenuhi dengan menyisipkan file video di dalamnya. Selain itu, penggunaan file video sebagai media pembelajaran mendukung implementasi pembelajaran saintifik pada kurikulum 2013. Namun, belum semua guru memiliki kemampuan untuk mengemas file video tersebut dalam bentuk media pembelajaran. Tujuan penelitian ini adalah untuk meningkatkan kemampuan guru-guru di SMA Negeri 1 Teras dan SMA Negeri 1 Boyolali dalam membuat media pembelajaran berbasis VAK dengan kombinasi software Format Factory, U-Lead dan PowerPoint. Hasil penelitian menunjukkan bahwa terjadi peningkatan kemampuan para guru di SMA Negeri 1 Teras dan SMA Negeri 1 Boyolali dalam membuat media pembelajaran. Peningkatan kemampuan guru-guru tersebut berada di atas target yang direncanakan. Rerata peningkatan kemampuan guru-guru di SMA Negeri 1 Teras 7,87% di atas target, sedangkan di SMA Negeri 1 Boyolali 9,58% di atas target. Kata kunci: Media Pembelajaran, Format Factory, U-Lead, PowerPoint Students have different learning styles. Learning styles include visual learners, auditory learners, and kinesthetic learners. A teacher must be able to fulfill the needs of individual students\u27 learning styles. One way that can be applied is using Visual, Audio and Kinesthetic (VAK) learning media based. VAK-learning media based can be created by inserting video files on it. In addition, using video file as a learning media can support the implementation of scientific learning on the 2013 curriculum. However, not all teachers have the ability to use video files into a learning media. The purpose of this study is to improve the teachers\u27 ability at SMA Negeri 1 Teras and SMAN 1 Boyolali on making VAK-learning media based with a combination of Format Factory, U-Lead and PowerPoint software. The results showed that the teachers\u27 ability on making VAK-learning media based was increased. Increased the teachers\u27 ability was above planned target score. The mean score of the teachers\u27 ability at SMA Negeri 1 Teras 7.87% above the target, while at SMAN 1 Boyolali 9.58% above the target
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