128,459 research outputs found
Marissa Holst
No full textHolst, M., Doudna, K., Chen, J., Routh, B., (2021, November). Self-care, adverse childhood experiences (ACEs), depressive symptoms, and household food insecurity among emerging adults. Society for the Study of Emerging Adulthood Annual Conference, Virtual.https://digitalcommons.morris.umn.edu/cosa2022/1021/thumbnail.jp
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Probing Surfaces with Thermal He Atoms: Scattering and Microscopy with a Soft Touch
No full textHelium atom scattering (HAS) is a well established technique, particularly suited for the investigation of insulating and/or fragile materials and light adsorbates including hydrogen. In contrast to other beam techniques based on Xrays or electrons, low energy (typically less than 100 meV) He atoms are scattered
by the tail of the electron density distribution which spill out from a surface, therefore HAS is strictly a nonpenetrating technique without any sample damage. HAS
has been used to investigate structural properties of crystalline surfaces, including precise determination of atomic step heights, for monitoring thin film growth, to
study surface transitions such as surface melting and roughening and for determining the presence and properties of adsorbates. Energy resolved HAS can provide
information about surface vibrations (phonons) in the meV range and surface diffusion.
This chapter provides a brief introduction to HAS with an outlook on a new, promising surface science technique: Neutral Helium Microscopy
Migration and Money - What Determines Remittances?: Evidence from Germany
No full textThe determinants of migrants' remittances are the subject of this study based on German SOEP data. For our analysis of the probability and amount of remittances, we do not restrict ourselves on immigrants with a foreign citizenship, but focus on all individuals with a migration background. Major findings are: first, the degree of integration into German society matters. Second, the probability to remit is not dominated by income. Third, foreigners living in Germany are not a homogenous group concerning their remittance behavior: people with Turkish and former Yugoslavian citizenship, who are facing a comparable strong pressure for return migration, remit significantly more than others. The study points to potentially interesting directions for future research: (a) deeper investigations of the extent to which the legal status of the migrant influences cross-border transfer behavior and (b) reconsidering the theoretical arguments since the motive for remittances might have changed during the ongoing globalization process..Remittances, international migration, altruism
Holst State Forest
No full textThe Holst State Forest is a 330 acre forest deeded to the Iowa Conservation Commission in 1939 by Mr. B. P. Holst, Sr., a prominent Boone businessman. In 1940 the Forestry Department at Iowa State accepted the responsibility of managing the forest as a demonstration forest for research and recreation. In 1947 the management was turned over to the Forestry Club where students could implement creative management experience. Since then management and student activity has been sporadic and during the 1960’s the forest has generally been neglected.</p
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Particle–wave discrimination in Poisson spot experiments
No full textMatter–wave interferometry has been used extensively over the last few years to demonstrate the quantum-mechanical wave nature of increasingly larger and more massive particles. We have recently suggested the use of the historical Poisson spot setup to test the diffraction properties of larger objects. In this paper, we present the results of a classical particle van der Waals (vdW) force model for a Poisson spot experimental setup and compare these to Fresnel diffraction calculations with a vdW phase term. We include the effect of disc-edge roughness in both models. Calculations are performed with D2 and with C70 using realistic parameters. We find that the sensitivity of the on-axis interference/focus spot to disc-edge roughness is very different in the two cases. We conclude that by measuring the intensity on the optical axis as a function of disc-edge roughness, it can be determined whether the objects behave as de Broglie waves or classical particles. The scaling of the Poisson spot experiment to larger molecular masses is, however, not as favorable as in the case of nearfield light-grating-based interferometers. Instead, we discuss the possibility of studying the Casimir–Polder potential using the Poisson spot setup
Myrcia damaniensis R. Flores, B. Holst & A. Ibanez, sp. nov.
No full text1. Myrcia damaniensis R. Flores, B. Holst & A. Ibáñez sp. nov. Type:— PANAMA. Comarca Ngäbe-Bugle: Humedal de Damani-Guariviara, Laguna de Damani. Vegetación de laguna, 5 m, 8°55’47”N, 81°41’45”W, 7 June 2013 (fl.), R. Flores, A. Ibáñez, N. Flores, A. Espinosa, T. Santiago & H. Taylor 3081 (holotype: PMA!) Figure 3, Figure 4 A-C. Diagnosis: — Myrcia damaniensis is similar to Myrcia chytraculia (Linnaeus 1759: 1056) A.R. Lourenço & E. Lucas (in Lourenço et al. 2018: 74) var. americana (McVaugh 1963: 404) G.P. Burton & E. Lucas (in Burton et al. 2021: 1023). Nevertheless, it can be easily distinguished by the size of its leaves ( 15 cm), leaf blades, elliptic, widely elliptic or suborbicular (vs. elliptic-ovate) and leaves with nearly indiscernible or weakly evident secondary venation on both surfaces (vs. leaves with prominent venation on abaxial surface). The apex in both species can be acuminate but M. damaniensis can also have a caudate or cuspidate apex. Description: —Shrubs or trees, 4–8 m; young leaves and branchlets, petioles and inflorescences with appressed reddish-brown indument; trichomes dibrachiate; branchlets terete, young branchlets slightly complanate and compressed at nodes. Leaves opposite, petiolate, the petioles 6–11 × 1–1.5 mm, channeled, with scattered trichomes; blades elliptic, widely elliptic or suborbicular, 7–12.2 × 3.5–6.5 cm, chartaceous, adaxial surface with scattered trichomes, green when fresh, brown, light brown or greenish-brown when dry, abaxial surface sparsely pubescent, green when fresh and light brown when dry, glands inconspicuous but visible at 10×; apex caudate or cuspidate, abruptly acuminate or acuminate; base acute or acuminate; midvein adaxially sulcate and depressed distally, with a few scattered trichomes, abaxially prominent, convex, distally attenuating, sparsely pubescent; lateral veins 13–24 per side, nearly indiscernible or weakly evident on adaxial and abaxial surfaces, ascending from the midvein to a marginal vein which equals the lateral veins in prominence and is slightly arched between ca. 1.8–2 mm from the margin. Inflorescences panicles, branched, densely covered with appressed, reddish brown trichomes, subterminal, one or two per axil, 8–12 × 3–7 cm, ca. 100 flowers per panicle, peduncle 3–7 cm × 1–1.2 mm, slightly winged and mostly distally flattened, axes angulate to quadrangular, bracts not seen. Flowers with pedicels 0.5–1 mm long; bracteoles caducous, densely covered with appressed trichomes, ca. 0.7 × 0.3 mm, lanceolate or narrowly lanceolate, apex acute; buds 1.8–2.3 mm long (including hypanthium), ovoid, densely covered with appressed trichomes; hypanthium ca. 1.2 mm long, prolonged ca. 1 mm beyond the summit of the ovary, densely covered with appressed trichomes, calyptra ca. 2 mm wide, shortly apiculate; petals absent; stamens ca. 20; anthers reniform, ca. 0.3 mm long; filaments ca. 2–3 mm long. Ovary bilocular, 2 ovules per locule; style ca. 4–5 mm long; stigma punctate. Fruit globose, 3–5 × 3–6 mm, crowned by the hypanthium, glabrescent and pubescent towards the apex, pericarp thin-walled, less than 1 mm thick. Seeds one or two, 2.5–6 mm diameter, globose or semi–spheroid. Distribution, habitat and phenology:—This species has been found on the shores of Damani and Oiba lagoons and along the channels of the wetland, in areas of mixed swamp forest with abundant Campnosperma panamense (Fig. 2A). One flowering specimen was collected in June, and fruiting specimens in September and October. Conservation:— Myrcia damaniensis has been found only in the Damani region, within the protected area Damani-Guariviara Wetlands of International Importance. Despite its protected status, the forests in the area are being cut down for subsistence agriculture and cattle ranching by an increasing population. This situation may reduce its small area of occupation (AOO) which is estimated just at 4 km ²; therefore, we consider that this species fits the category Endangered [EN B2ab (ii, iii, iv)] of the IUCN Red List and criteria (IUCN 2012). Etymology:—The epithet of this species refers to the Damani lagoon, the largest in the Damani-Guariviara Wetlands. Discussion:— Myrcia damaniensis has the calyx lobes fused into a single structure that opens circularly through a calyptra. Based on this morphological characteristic, this species would belong in Myrcia sect. Calyptranthes (Swartz 1788: 79) A. R. Lourenço & E. Lucas, according to a recent phylogenetic study (Lucas et al. 2018: 3). Myrcia damaniensis is apparently related to Myrcia chytraculia var. americana. Both species have inflorescences alate, multiflorous and covered with a reddish pubescence. However, both species are distinguished by the characters listed in the diagnosis. With the description of Myrcia damaniensis, 34 species of Myrcia are recognized in Panama. Paratypes:— PANAMA. Comarca Ngäbe-Bugle: Humedal de Damani-Guariviara, laguna de Oiba, vegetación de laguna, 5 m, 8°50’57”N, 81°38’05”W, 17 September 2011 (fr.), A . Ibáñez & R. Flores 7377 (PMA!, UCH!); Humedal de Damani-Guariviara, laguna de Damani, vegetación de laguna (orilla), 5 m, 8°55’56”N, 81°42’35”W, 19 September 2011 (fr.), R . Flores & A. Ibáñez 1415 (PMA!, MO!); Humedal de Damani-Guariviara, Cerari, bosque inundable, 16 m, 8°56’34”N, 81°42’27”W, 26 October 2014 (fr.), R . Flores & T. Santiago 3647 (PMA!, SEL!).Published as part of Flores, Rodolfo, Holst, Bruce K. & Ibáñez, Alicia, 2022, Two new species of Myrtaceae from the western Caribbean forests of Panama, pp. 61-71 in Phytotaxa 568 (1) on pages 64-66, DOI: 10.11646/phytotaxa.568.1.4, http://zenodo.org/record/718426
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