862 research outputs found
Lobelia alanae Pérez-Pérez & Ayers & Amith 2022, sp. nov.
No full textLobelia alanae sp. nov. M. A. Pérez-Pérez & T. J. Ayers (Figures 1–2) Type:— MEXICO. Puebla. Municipality of Ayotoxco de Guerrero. Copales. In a site called Espinazo del Diablo, near the Apulco river, 153 m elevation, 20.09053°N, 97.45086°W. 20 September 2016, M. Jiménez-Chimil and M. Gorostiza-Salazar 31421 (holotype: US!, isotypes: HUAP, IEB!, K!, MEXU, MO!). Diagnosis: Similar to Lobelia porphyrea, but with cauline leaves, a hemispheric hypanthium, calyx lobes with 1–2 pair of elongate, purple teeth at margins and one apical purple tooth and a spherical capsule 5–7 mm in diameter. Perennial herb from a woody caudex. Stems erect, branched well above base or unbranched, to 80 cm high, greenish, hirtellous. Leaves cauline, alternate, subsessile or petiolate, petioles 2–22 mm long; blades ovate to ovatelanceolate, 3–11.5 cm long, 0.9–4.3 cm wide, abruptly reduced above; base long-attenuate; apex apiculate-acuminate; margins minutely serrulate or biserrate, with white callosities at tips of teeth; glabrous to hirtellous especially along veins abaxially and near margins. Inflorescence racemose, bracteate; bracts sessile, linear-lanceolate, 5–9 mm long, 0.4–1.5 mm wide; apex apiculate; margins continuous with extremely small wings on stem; margins serrate, tipped with purple, elongate, callose teeth. Flowers pedicellate; pedicels 0.6–1.4 cm long, bi-bracteolate at base; bracteoles 1–2 mm long with a prominent purple apical gland, hirtellous or ciliate; hypanthium hemispheric, ca. 1.2–2.0 mm long, 2.3–2.9 mm wide, hirtellous, prominently veined; calyx lobes subulate, the two laterals often curved upward and overlapping the dorsal lobe in flower, 1.3–2.5 mm long, 0.5–0.7 mm wide, with 1 purple apical callosity, and 1–2 pair of marginal elongate pubescent purple callosities near base or middle; corolla bilabiate, pink; tube cylindrical, 10–16 mm long, ca. 4 mm in diameter, slit dorsally except for ca. 3 mm at base, outer surface, hirtellous; limb bilabiate, bent upward ca. 45 degrees in bud; upper lobes oblong-spatulate, 3.3–4.3 mm long, 1.4–1.6 mm wide, acute, margins entire to irregularly undulate when dry, hirtellous along veins or glabrate; lower lobes obovate, 6.9–7.3 mm long, 3.3–4.5 mm wide, cuspidate, margins entire to irregularly undulate when dry, pink with a white patch at throat, hirtellous along veins or glabrate; stamens shorter than corolla tube; filaments white, free at base for 5–7 mm then connate into a tube ca. 4 mm long, the anthers blue-black, connate, 1.6–2.0 mm long, the three upper anthers covered with minute greyish hairs, the two lower anthers glabrous except for the numerous minute linear trichomes at apex; ovary bilocular, one-half inferior in flower, the style 10–12 mm long, the stigma lobes with minute whiteish hairsbelow. Capsule spherical, pendant on a reflexed pedicel, three-quarters or more inferior, 5–7 mm in diameter, strongly 10-veined, the veins persistent; seeds ca. 36, yellow to brown, ellipsoid, ca. 1 mm long, elongate-scabrate to reticulate-foveolate, shiny. Chromosome number: unknown. Specimens examined: MEXICO. Puebla. Municipality of Jonotla, Xiloxochit. Densely wooded hillside above Apulco river at a site called “Isla” near El Porvenir, about 20 minute walk from the Copalco chapel. 176 m, 20.10131° N, 97.45608° W, 28 May 2015, Ceferino Salgado-Castañeda 2540 (HUAP, MEXU, US!). Municipality of Ayotoxco de Guerrero. Copales.At a site called Espinazo del Diablo, alongside the road to Atsalan, 177 m, 20.09024°N, 97.45182°W, 01 July 2016, M. Jiménez-Chimil and M. Gorostiza-Salazar 31381 (ASC!, HUAP, MEXU, MO, US). Veracruz, Municipality of Mecatlán, to the north of the municipality, near the location of the antennas, 663 m, 20.20633°N, 97.67272° W, 7 May 2017, Osbel López-Francisco and Ceferino Salgado-Castañeda 76078 (ASC!, HUAP, MEXU, US); Municipality of Coahuitlán, along the major road Coahuitlán-Crucero, at the entrance to the village of Coahuitlán, 701 m, 20.25681° N, 97.73054° W, 10 August 2017, Osbel López-Francisco and Ceferino Salgado-Castañeda 76237 (ASC!, MEXU, US). Etymology: This species is named in the honor of Alana Amith who assisted her father, Jonathan Amith, in his work on the “Comparative Mesoamerican Ethnobiology of the Sierra Norte de Puebla ”. Habitat and conservation: Secondary Forest, tropical dry forest, and cloud forest. The primary botanical elements associated with Lobelia alanae are Bursera Jacquin ex Linnaeus (1762: 471), Leucaena Bentham (1842: 416–417), Ceratozamia Brongniart (1846: 7–8), Saurauia Willdenow (1801: 407), Inga Miller (1754: 498), and Cecropia obtusifolia Bertoloni (1840: 141). The Sierra Norte of Puebla is an important coffee region in Mexico. The coffee plantations are agroecosystems that include 256 native and 63 introduced species (Martinez et al. 2007). The type locality of L. alanae is at 153 meters elevation in a heavily shaded area about 20 meters above the Apulco river. The two other lowland collections (176 m) were also near the same river at a distance of 100 and 50 m. The two higher elevation collections in Veracruz (663 and 701 m) were not associated with a water way and, unlike the previous collections, they occurred in a relatively disturbed environment. Lobelia alanae is distributed in two Mexican states (Figure 3). The field teams noted that L. alanea grew in colonies. According to the amplitude of the range represented by the species distribution (less than 5% of the Mexican territory), this taxon is categorized as very restricted (SEMARNAT, 2010).Published as part of Pérez-Pérez, Miguel A., Ayers, Tina J. & Amith, Jonathan D., 2022, A new species of Lobelia (Campanulaceae: Lobelioideae) from the Sierra Madre Oriental, Mexico, pp. 1-7 in Phytotaxa 568 (1) on pages 2-5, DOI: 10.11646/phytotaxa.568.1.1, http://zenodo.org/record/718422
Language documentation and natural history: A synergistic and interdisciplinary approach to ethnobiology
No full textThe nomenclature, classification, and use of biotaxa should be a significant component of language documentation. It involves complex lexical semantics and classificatory schemes, creats a thematic stimulus for corpus development, and can facilitate community collaboration to preserve endangered language and traditional ecological knowledge. This presentation proposes a synergistic partnership among biologists, linguists, indigenous communities, and ethnographers to explore these issues
Resource-based view of social media as a source of sustained competitive advantage
No full textThesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 59-62).Executive summary: Social Media is increasingly becoming prevalent and firms are increasingly adopting social media. Managers are concerned about the value social media provides and how it can be used for competitive advantage. The resource-based-view of a firm suggests that resources that are rare, valuable, imperfectly imitable and non-substitutable can create sustained competitive advantage. This thesis uses the resource-based view of the firm applied to five case studies of Wiki implementation and analyzes how social media could create sustained competitive advantage. The analysis in this thesis finds that social media can be used to enhance existing resources and capabilities in a firm. These organizational capabilities are hard to imitate because of path dependency, social complexity and causal ambiguity and thus provide the firm sustained competitive advantage. The effective implementation of social media by a firm requires that it identify its core capabilities and resources to enhance, identify the gap that exists between the needed capabilities and the capabilities the firm possesses and then systematically embed social media in the daily routines and processes of the organization. This can be done by adopting appropriate social media guidelines, training and policy enforcement. Adopting social media by itself will not confer a firm sustained competitive advantage but capabilities thus enhanced could confer a firm sustained competitive advantage.by Amith Pervaje.S.M.in Engineering and Managemen
FIGURE. Lobelia alanae M.A in A new species of Lobelia (Campanulaceae: Lobelioideae) from the Sierra Madre Oriental, Mexico
No full textFIGURE. Lobelia alanae M.A. Pérez-Pérez & T. Ayers A. Flowering branch. B. Flower from above showing lateral calyx lobes crossed over dorsal lobe. C. Capsule. D. Seed about 1 mm in length. E. Landscape of Espinazo del Diablo and Apulco river. F. Type locality. Pictures taken from the type collection M. Jiménez-Chimil and M. Gorostiza-Salazar 31421.Published as part of Pérez-Pérez, Miguel A., Ayers, Tina J. & Amith, Jonathan D., 2022, A new species of Lobelia (Campanulaceae: Lobelioideae) from the Sierra Madre Oriental, Mexico, pp. 1-7 in Phytotaxa 568 (1) on page 4, DOI: 10.11646/phytotaxa.568.1.1, http://zenodo.org/record/718422
New Record and the Nest Description of the Nocturnal Sweat Bee Megalopta tetewana (Hymenoptera: Halictidae)
No full textThis article documents a significant range extension of the sweat bee Megalopta tetewana, some 300 kilometers south of a previous register of this bee. The collection of this bee was part of Amith\u27s ethnoentomological research along the Pacific Coast of Guerrero
Adaptive control of hypersonic vehicles in presence of actuation uncertainties
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 73-75).The thesis develops a new class of adaptive controllers that guarantee global stability in presence of actuation uncertainties. Actuation uncertainties culminate to linear plants with a partially known input matrix B. Currently available multivariable adaptive controllers yield global stability only when the input matrix B is completely known. It is shown in this work that when additional information regarding the structure of B is available, this difficulty can be overcome using the proposed class of controllers. In addition, a nonlinear damping term is added to the adaptive law to further improve the stability characteristics. It is shown here that the adaptive controllers developed above are well suited for command tracking in hypersonic vehicles (HSV) in the presence of aerodynamic and center of gravity (CG) uncertainties. A model that accurately captures the effect of CG shifts on the longitudinal dynamics of the HSV is derived from first principles. Linearization of these nonlinear equations about an operating point indicate that a constant gain controller does not guarantee vehicle stability, thereby motivating the use of an adaptive controller. Performance improvements are shown using simulation studies carried out on a full scale nonlinear model of the HSV. It is shown that the tolerable CG shifts can be almost doubled by using an adaptive controller as compared to a linear controller while tracking reference commands in velocity and altitude.by Amith Somanath.S.M
Hemodynamics and wall shear metrics in a pulmonary autograft : comparing a fluid-structure interaction and computational fluid dynamics approach
No full textObjective: In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. Methods: The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. Results: Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. Conclusion: FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA
HEB876240_suppl_mat – Supplemental material for Collective Avoidance of Social and Health Venues and HIV Racial Inequities: Network Modeling of Venue Avoidance on Venue Affiliation, Social Networks, and HIV Risk
No full textSupplemental material, HEB876240_suppl_mat for Collective Avoidance of Social and Health Venues and HIV Racial Inequities: Network Modeling of Venue Avoidance on Venue Affiliation, Social Networks, and HIV Risk by Kayo Fujimoto, Peng Wang, Dennis H. Li, Lisa M. Kuhns, Muhammad Amith and John A. Schneider in Health Education & Behavior</p
Autism and gambling: A systematic review, focusing on neurocognition
No full textAutism spectrum disorders (hereafter autism) are prevalent and often associated with elevated rates of substance use disorders. A subset of people who gamble develop gambling disorder, which is functionally impairing. Characterization of relationships between autism and gambling, particularly as relates to cognition, may have important implications. We conducted a systematic review of the literature. Nine out of 343 publications were found eligible for inclusion. Most studies examined decision-making using cognitive tasks, showing mixed results (less, equivalent or superior performance in autistic people compared to non-autistic people). The most consistent cognitive finding was relatively slower responses in autistic people on gambling tasks, compared to non-autistic people. One study reported a link between problem gambling and autism scores, in people who gamble at least occasionally. This systematic review highlights a profound lack of research on the potential neurocognitive overlap between autism and gambling. Future work should address the link between autism and behavioral addictions in adequately powered samples, using validated tools
Controlling stochastic growth processes on lattices: Wildfire management with robotic fire extinguishers
No full textForest fires continue to cause considerable social and economic damage. Fortunately, the emergence of new robotics technologies, including capable autonomous unmanned aerial vehicles, may help improve wildfire management in the near future. In this paper, we characterize the number of vehicles required to combat wildfires, using a percolation-theoretic analysis that originated in the mathematical physics community. We model the wildfire as a stochastic growth process on a square lattice, where the local growth probabilities depend on the presence of robotic fire-extinguishing vehicles. We develop two control policies: First treats only a fraction of burning nodes at a given time, and the second treats burning nodes only at finite time intervals. We characterize the conditions under which these policies can stabilize a wildfire, i.e., ensure the fire stops eventually almost surely. We also provide computational results which demonstrate our theoretical analysis.National Science Foundation (U.S.) (Grant 1350685
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