1,373 research outputs found
Ryan B. Stephens Catalog 2010-2013
No full textCollectors notes and catalogs for Ryan B. Stephens covering collecting activities from 2010-201
Nutritional and environmental factors influence small mammal seed selection in a northern temperate forest
No full textData associated with the manuscript: Moore, N. B., Stephens, R. B., and R. J. Rowe. 2022. Nutritional and environmental factors
influence small mammal seed selection in a northern temperate forest. Ecosphere</i
Exploring sexual dimorphism of the modern human talus through geometric morphometric methods
No full textSex determination is a pivotal step in forensic and bioarchaeological fields. Generally, scholars focus on metric or qualitative morphological features, but in the last few years several contributions have applied geometric-morphometric (GM) techniques to overcome limitations of traditional approaches. In this study, we explore sexual dimorphism in modern human tali from three early 20th century populations (Sassari and Bologna, Italy; New York, USA) at intra- and interspecific population levels using geometric morphometric (GM) methods. Statistical analyses were performed using shape, form, and size variables. Our results do not show significant differences in shape between males and females, either considering the pooled sample or the individual populations. Differences in talar morphology due to sexual dimorphism are mainly related to allometry, i.e. size-related changes of morphological traits. Discriminant function analysis using form space Principal Components and centroid size correctly classify between 87.7% and 97.2% of the individuals. The result is similar using the pooled sample or the individual population, except for a diminished outcome for the New York group (from 73.9% to 78.2%). Finally, a talus from the Bologna sample (not included in the previous analysis) with known sex was selected to run a virtual resection, followed by two digital reconstructions based on the mean shape of both the pooled sample and the Bologna sample, respectively. The reconstructed talus was correctly classified with a Ppost between 99.9% and 100%, demonstrating that GM is a valuable tool to cope with fragmentary tali, which is a common occurrence in forensic and bioarchaeological contexts.</div
Unravelling morphological changes of the human talus during growth
No full textThe human talus, being located between the lower limb and foot, plays an essential role in distributing the weight of the body during locomotion. One of its most important functions during this process is in allowing for foot movements while efficiently dividing weight between its anterior and posterior portions, where it articulates with the navicular and calcaneus, respectively [1]. As such, the talus plays a pivotal role in the different stages of human locomotion, from crawling, to initial bipedal acquisition, to full striding bipedalism at age 8 [1]. Unfortunately, little is known about the morphological changes of the talus during the first years of life, when infants acquire upright posture and gait maturation.
Using a (semi)landmark based approach we analyse an ontogenetic sample of modern human tali with the aim of exploring the morphological variation of the talus during growth. From this we assess if the variation may then be related to the acquisition and transition to full bipedal locomotion, which might ultimately provide insight into the evolution of hominin bipedalism.
The sample consists of 21 juvenile tali aged between 1.5 years and 11 years: 12 individuals from the Collection of Bologna, Italy (sex and age at death known) [2]; five from the archaeological sample of Roccapelago (Italy) [3]; four from the archaeological sample of Norris Farms #36 (Illinois, USA). All specimens were microCT scanned with a resolution of 20-40 μm. Avizo 9.3® (Visualization Sciences Group, SAS) was used to evaluate the quality of and pre-process the reconstructed scan data (e.g. crop or resample). Segmentation of the image data was performed using the MIA-clustering method [4] and then processed in Medtool 4.2 (Dr. Pahr Ingenieurs.e.U) to obtain 3D meshes of each talus. A template of 11 landmarks, 61 curve semilandmarks and 144 surface semilandmarks was created in Viewbox (dHAL Software) and applied to the 21 tali. The (semi)landmark configuration was superimposed by Generalized Procrustes Analysis, and semilandmarks were allowed to slide against recursive updates of the Procrustes consensus [5]. Finally, a form space Principal Component Analysis was carried out to explore talar shape variation during growth. Data were processed in R 3.4.3 (The R Foundation for Statistical Computing, 2017).
The first three PCs explain 92.9% of the total variation. Most of the morphometric variation is explained by PC1 (89.8%), i.e. ontogenetic allometry, where negative scores account for small, sub-parallelepiped talar morphology (the youngest individuals), while positive scores account for an elongation of the entire body of the talus, due to the development of the neck, and a clear growth of the lateral malleolar facet, while the posterior side of the trochlear facet is not well defined yet. The anterior calcaneal facet is well developed since the youngest phases (negative scores), while the posterior calcaneal facet becomes larger, less triangular, and more concave towards PC1 positive. PC2 (1.7%) and PC3 (1.4%) describe only subtle morphological differences. Negative values of PC2 account for a longer lateral ridge, that shortens along positive values, due to the growth of the talar head, development of the neck, trochlea, and lateral malleolar facet, with a more concave aspect of the lateral side. It is also possible to discern a narrowing of the sulcus tali and a clear medial rotation of the talar head. PC3 negative scores show a more compact shape, that becomes higher along positive values with the development of the posterior calcaneal facet and head.
This study is part of an ongoing project focusing on ontogenetic changes. Here we present preliminary results showing how external talar morphology varies during the early stages of human bipedalism. Future analyses will combine external morphological analyses with an assessment of trabecular bone architecture, thus providing a more holistic vision of these changes during development.
Acknowledgements
This project is funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 724046 - SUCCESS); website: http://www.erc-success.eu/. We are grateful to Dr Mirko Traversari for his willingness on the use of the Roccapelago sample.
References:
[1] Hellier, C.A., & Jeffery, N. 2006. Morphological plasticity in the juvenile talus. Foot and Ankle surgery, 12(3), 139-147.
[2] Belcastro, M.G., Bonfiglioli, B., Pedrosi, M.E., Zuppello, M., Tanganelli, V., & Mariotti, V. 2017. The history and composition of the identified human skeletal collection of the Certosa Cemetery (Bologna, Italy, 19th‐20th century). International Journal of Osteoarchaeology. DOI: 10.1002/oa.2605
[3] Figus, C., Traversari M., Scalise L. M., Oxilia G., Vazzana A., Buti L., Sorrentino R., Gruppioni G., Benazzi, S. 2017. The study of commingled non-adult human remains: Insights from the 16th-18th centuries community of Roccapelago (Italy). Journal of Archaeological Science: Reports, 14:382-391
[4] Dunmore C.J., Wollny G., Skinner M.M. (2018) MIA-Clustering: a novel method for segmentation of paleontological material. PeerJ 6:e4374
[5] Rohlf, F.J., Slice, D. 1990. Extensions of the Procrustes method for the optimal superimposition of landmarks. Syst. Biol. 39, 40-59
Singing from the Grave: DNA from a 180 Year Old Type Specimen Confirms the Identity of Chrysoperla carnea (Stephens)
No full textCopyright: © 2015 Price et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article.NHM Repositor
57Fe Mössbauer-effect study of preferential site occupancy in quasicrystalline Al86Cr14−xFex alloys
No full textPT: J; CR: BANCEL PA, 1986, PHYS REV B, V33, P7917 BLACK PJ, 1955, ACTA CRYSTALLOGR, V8, P175 CAHN JW, 1986, J PHYS-PARIS, V47, P415 COOPER M, 1966, ACTA CRYSTALLOGR, V20, P614 COOPER M, 1967, ACTA CRYSTALLOGR, V23, P1106 CORBY RN, 1977, ACTA CRYSTALLOGR B, V33, P3468 DUNLAP RA, UNPUB J PHYS F DUNLAP RA, 1986, HYPERFINE INTERACT, V28, P963 DUNLAP RA, 1986, J PHYS F MET PHYS, V16, P1247 DUNLAP RA, 1987, J PHYS F MET PHYS, V17, L39 EIBSCHUTZ M, 1986, PHYS REV LETT, V56, P169 EIBSCHUTZ M, 1987, PHYS REV LETT, V59, P2443 GUYOT P, 1986, J PHYS-PARIS, V47, P389 HAUSER JJ, 1986, PHYS REV B, V33, P3577 HENLEY CL, 1986, PHYS REV B, V34, P797 HENLEY CL, 1987, COMMENTS CONDENSED M, V13, P59 LAWTHER DW, UNPUB MA J, 1986, PHYS REV LETT, V57, P1611 MACKAY AL, 1962, ACTA CRYSTALLOGR, V15, P916 NASU S, 1974, J PHYS F MET PHYS, V4, L24 SCHURER PJ, 1986, SOLID STATE COMMUN, V59, P619 STEPHENS PW, 1986, PHYS REV LETT, V56, P1168 SWARTZENDRUBER LJ, 1985, PHYS REV B, V32, P1383 WARREN WW, 1986, PHYS REV B, V34, P4902; NR: 24; TC: 40; J9: PHYS REV B; PG: 4; GA: P9232Source type: Electronic(1
The effects of sodium azide and sodium cyanide on the oxygen consumption of the eggs of salmo fario, 1950
No full textSearch for exclusive b → u transitions in hadronic decays of B mesons involving Ds+ and Ds*+ mesons
No full textcomplete author list:
Alexander J.; Bebek C.; Berkelman K.; Bloom K.; Browder T.; Cassel D.; Cho H.; Coffman D.; Drell P.; Ehrlich R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Jones C.; Jones S.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Ng C.; Nordberg E.; Patterson J.; Peterson D.; Riley D.; Salman S.; Sapper M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Stephens R.; Yelton J.; Cinabro D.; Henderson S.; Kinoshita K.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Bergfeld T.; Eisenstein B.; Gollin G.; Ong B.; Palmer M.; Selen M.; Thaler J.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Bean A.; Besson D.; Coppage D.; Copty N.; Davis R.; Hancock N.; Kelly M.; Kwak N.; Lam H.; Kubota Y.; Lattery M.; Nelson J.; Patton S.; Perticone D.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Alam M.; Kim I.; Nemati B.; O'Neill J.; Severini H.; Sun C.; Zoeller M.; Crawford G.; Daubenmier C.; Fulton R.; Fujino D.; Gan K.; Honscheid K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Morrow F.; Skovpen Y.; Sung M.; White C.; Butler F.; Fu X.; Kalbfleisch G.; Ross W.; Skubic P.; Snow J.; Wang P.; Wood M.; Brown D.; Fast J.; McIlwain R.; Miao T.; Miller D.; Modesitt M.; Payne D.; Shibata E.; Shipsey I.; Wang P.; Battle M.; Ernst J.; Kwon Y.; Roberts S.; Thorndike E.; Wang C.; Dominick J.; Lambrecht M.; Sanghera S.; Shelkov V.; Skwarnicki T.; Stroynowski R.; Volobouev I.; Wei G.; Zadorozhny P.; Artuso M.; He D.; Goldberg M.; Horwitz N.; Kennett R.; Mountain R.; Moneti G.; Muheim F.; Mukhin Y.; Playfer S.; Rozen Y.; Stone S.; Thulasidas M.; Vasseur G.; Zhu G.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Akerib D.; Barish B.; Chadha M.; Chan S.; Cowen D.; Eigen G.; Miller J.; O'Grady C.; Urheim J.; Weinstein A.; Acosta D.; Athanas M.; Masek G.; Paar H.; Gronberg J.; Kutschke R.; Menary S.; Morrison R.; Nakanishi S.; Nelson H.; Nelson T.; Richman J.; Ryd A.; Tajima H.; Schmidt D.; Sperka D.; Witherell M.; Procario M.; Yang S.; Balest R.; Cho K.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Alexander J.P
Developing Learning Trajectory For Enhancing Students’ Relational Thinking
No full textAlgebra is part of Mathematics learning in Indonesian curriculum. It takes one half of the teaching hours in senior high school, and one third in junior high school. However, the learning trajectory of Algebra needs to be improved because teachers teach computational thinking by applying paper-and-pencil strategy combining with the concepts-operations-example-drilling approach. Mathematics textbooks do not give enough guidance for teachers to conduct good activities in the classroom to promote algebraic thinking especially in the primary schools.
To reach Indonesian Mathematics teaching goals, teachers should develop learning trajectories based on pedagogical and theoretical backgrounds. Teachers need to have knowledge of student’s developmental progressions and understanding of mathematics concepts and students’ thinking. Research shows that teachers’ knowledge of student’s mathematical development is related to their students’ achievement. In fostering a greater emphasis on algebraic thinking, teachers and textbooks need to work more closely together to develop a clearer learning trajectory. Having this algebraic thinking, students developed not only their own character of learning and thinking but also their attitude, attention and discipline.
Key Words: Learning Trajectory, Relational Thinkin
Small Mammal Assemblages in Natural Plant Communities of Wisconsin
No full textSmall mammals play important roles in Wisconsin ecosystems; however, considering
their importance and ubiquity, we know little about the best way to capture them or how to
distinguish between cryptic species. Additionally, we do not have consistent information
regarding distributions and habitat requirement of many small mammal species. This study
was broken into 4 parts in order to address these knowledge gaps.
When evaluating richness and diversity of small mammal communities it is
important to consider the impact that trap efficacy may have on these indices. The
objectives of my study were to determine species specific trap efficacy relative to
Sherman traps and pitfall traps, assess the impact of trap efficacy on measures of species
richness and diversity, and compare mortality rates between trap types, and if pitfall
covers reduce trap mortality. In the summers of 2009 and 2010, I trapped throughout
Wisconsin in 5 habitats. I used 180 transects (190 m-long) of 20 Sherman live traps
spaced every 10 m and 10 pitfall traps spaced every 20 m for 4 consecutive nights. I
trapped 3,261 small mammals of 22 species in 34,235 trap nights. Pitfall traps were more
effective at capturing shrews and voles, whereas Sherman traps captured more mice
(Peromyscus spp.) and squirrels. Irrespective of habitat type, both trap types together
captured significantly higher species richness and diversity than either trap type
independently. Covers significantly reduced mortality for Peromyscus spp., but not for
voles or shrews and covers reduced overall captures of voles. My results indicate that
Sherman and pitfall traps capture different portions of the small mammal community and,
regardless of the habitat type, should be used in combination when assessing species
richness and diversity.
In Wisconsin, white-footed mice (Peromyscus leucopus noveboracensis) and
woodland deer mice (P. maniculatus gracilis) are difficult to distinguish. Recent climatic
trends have facilitated encroachment of P. leucopus north into the range of P.
maniculatus, making unambiguous species identification imperative. Cranial and
external measurements have been used previously to differentiate these species.
However, since large geographic morphological variation occurs and most previous
studies used measurements from deceased specimens, definitive morphological
measurements need to be identified that can quickly and effectively classify live
Wisconsin Peromyscus spp. in the field. I live trapped Peromyscus spp. in central and
northern Wisconsin during the summer of 2010. I measured ear, tail, hindfoot, and
weight from live animals and collected tissue for genetic confirmation. In addition to
using mDNA analysis to identify samples to species, I collected measurements from 84 P.
maniculatus and 293 P. leucopus in 6 Wisconsin counties. I used discriminate function
analysis (DFA) to develop equations to identify characteristics that best separated mice to
species. By using ear length alone, 97.9% of the samples could be correctly classified
with most P. leucopus <17mm and most P. maniculatus ≥ 17mm. By adding weight to
the function, I was able to achieve 99.2% classification accuracy and with the addition of
tail was able to achieve 99.5% differentiation.
The arctic shrew (Sorex arcticus) and American water shrew (S. palustris) are
wide-spread boreal species. Sorex arcticus reaches its southern distribution in Wisconsin
and within the Midwest S. palustris also reaches its southern range extent in Wisconsin.
Although the ranges of both species are generally thought to occur in the Driftless Area
in the southwestern portion of Wisconsin, no occurrences have been documented from
the region. Within the past decade and half, the known distribution of these species has
changed dramatically. I used museum records and geo-referenced surveys to remap the
known distribution of S. arcticus and S. palustris in Wisconsin. Herein, I report records
of S. arcticus and S. palustris within the Driftless Area and extend the distribution of S.
arcticus and S. palustris south of their former range, including the most southerly extant
record of S. arcticus. This study emphasizes the continued value of voucher specimens
and museum collections.
Determining small mammal species habitat associations and environmental
characteristics, important in site occupancy, are central to understanding species biology
and community organization. During the summers of 2009 and 2010, I trapped small
mammals and measured habitat variables throughout the state of Wisconsin at 180 sites
spanning 13 natural habitats. I captured 3,261 individual small mammals of 22 species,
allowing for characterization of small mammal communities within natural habitats. I
was also able to model occupancy for 12 species using habitat covariates while
incorporating imperfect detection. Comparisons among small mammal communities
indicated that organization was based on soil moisture, abundance of trees, and climate.
Additionally, the most important covariates in predicting small mammal occupancy were
basal area, frequency and duration of wet periods, and minimum winter temperature. The
ability to detect differences in community similarity and species occupancy, based on
climate, is likely a product of the large geographical extent of this study, underscoring the
need to assess community structure at multiple scales. Given the importance of climate
in structuring these small mammal communities, predicted warming winter temperatures
could have considerable impacts on small mammal communities in the region.
Interestingly, occupancy of the meadow jumping mouse was best predicted by the
presence of precipitation before a trap check and availability of pitfall traps. These
conclusions would have been missed using other analyses that do not account for
imperfect detection. Finally, my results indicate that soil moisture, abundance of trees,
and climate are important for species occupancy and, at the community level, these
variables create regular and predictable community structure across a heterogeneous
landscape.Wisconsin Department of Natural Resources
(Bureau of Endangered Resources), Prairie Biotic Research, Inc., and the University of
Wisconsin – Stevens Point
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