573 research outputs found
DIET OF THE PYGMY PALM‐SWIFT (TACHORNIS FURCATA)
ABSTRACT We studied the diet of the Pygmy Palm‐Swift (Tachornis furcata) based on stomach contents of four individuals collected in Venezuela. The diet consisted of insects from 6 orders and 22 families and of three spiders. Hymenoptera, particularly fig wasps and their parasitoids, made up 71.32% of 750 prey items. Flies (Diptera) and aphids (Homoptera) were important prey items as well. Body length of 39 intact prey items ranged from 1.1 to 4.2 mm, with a mean of 2.03 mm. These prey sizes are consistent with that of other small swift species. RESUMEN ∙ Dieta del Vencejo Enano (Tachornis furcata)Estudiamos la dieta del Vencejo Enano (Tachornis furcata) en base a contenidos estomacales de 4 individuos coleccionados en Venezuela. La dieta estaba compuesta por insectos pertenecientes a seis órdenes y 22 familias y por tres arañas. Hymenoptera, en particular avispas del higo y sus parasitoides, formaron el 71.3% de 750 presas identificadas. Moscas (Diptera) y áfidos (Homoptera) también fueron ítems presa importantes. El tamaño de 39 ítems presa intactos medidos varió entre 1.1 y 4.2 mm con una media de 2.03 mm. Estos tamaños de presa son similares a los de otras especies de vencejos pequeños
Methods in Determinative Minerology
This 11 page thesis examines various schemes for determining minerals
Comparative analysis of rigidity across protein families
We present a comparative study in which 'pebble game' rigidity analysis is applied to multiple protein crystal structures, for each of six different protein families. We find that the main-chain rigidity of a protein structure at a given hydrogen bond energy cutoff is quite sensitive to small structural variations, and conclude that the hydrogen bond constraints in rigidity analysis should be chosen so as to form and test specific hypotheses about the rigidity of a particular protein. Our comparative approach highlights two different characteristic patterns ('sudden' or 'gradual') for protein rigidity loss as constraints are removed, in line with recent results on the rigidity transitions of glassy networks
New country and state records, and other notes for Mexican Buprestidae (Coleoptera)
Treatment is provided for 224 species and subspecies in the genera Acherusia, Acmaeodera, Actenodes, Agaeocera, Agrilus, Anthaxia, Brachys, Buprestis, Chalcangium, Chrysobothris, Colobogaster, Cyphothorax, Dicerca, Dismorpha, Euchroma, Hiperantha, Hylaeogena, Leiopleura, Lius, Mixochlorus, Omochyseus, Pachyschelus, Polycesta, Psiloptera, Spectralia, Taphrocerus, Tetragonoschema, Thrincopyge, Trypantius and Tyndaris. Of these, 44 are recorded for the first time from Mexico and 175 represent new state records. Adult host and/or habitat information is provided, usually from the label data, for 93 of the taxa. Larval host records are indicated for Chrysobothris analis LeConte, C. capitata Gory and Laporte, C. multistigmosa (Mannerheim) and C. sallei Waterhouse. Acmaeodera sinaloensis Duges has been discovered to breed in bamboo. A major taxonomic character of C. multistigmosa is discussed
The Database of Macromolecular Motions: new features added at the decade mark
The database of molecular motions, MolMovDB (), has been in existence for the past decade. It classifies macromolecular motions and provides tools to interpolate between two conformations (the Morph Server) and predict possible motions in a single structure. In 2005, we expanded the services offered on MolMovDB. In particular, we further developed the Morph Server to produce improved interpolations between two submitted structures. We added support for multiple chains to the original adiabatic mapping interpolation, allowing the analysis of subunit motions. We also added the option of using FRODA interpolation, which allows for more complex pathways, potentially overcoming steric barriers. We added an interface to a hinge prediction service, which acts on single structures and predicts likely residue points for flexibility. We developed tools to relate such points of flexibility in a structure to particular key residue positions, i.e. active sites or highly conserved positions. Lastly, we began relating our motion classification scheme to function using descriptions from the Gene Ontology Consortium
Stochastic kinetics of viral capsid assembly based on detailed protein structures
We present a generic computational framework for the simulation of viral
capsid assembly which is quantitative and specific. Starting from PDB files
containing atomic coordinates, the algorithm builds a coarse grained
description of protein oligomers based on graph rigidity. These reduced protein
descriptions are used in an extended Gillespie algorithm to investigate the
stochastic kinetics of the assembly process. The association rates are obtained
from a diffusive Smoluchowski equation for rapid coagulation, modified to
account for water shielding and protein structure. The dissociation rates are
derived by interpreting the splitting of oligomers as a process of graph
partitioning akin to the escape from a multidimensional well. This modular
framework is quantitative yet computationally tractable, with a small number of
physically motivated parameters. The methodology is illustrated using two
different viruses which are shown to follow quantitatively different assembly
pathways. We also show how in this model the quasi-stationary kinetics of
assembly can be described as a Markovian cascading process in which only a few
intermediates and a small proportion of pathways are present. The observed
pathways and intermediates can be related a posteriori to structural and
energetic properties of the capsid oligomers
A remarkable leaf mine induced by Tachygonus sp.n. (Coleoptera: Curculionidae: Curculioninae: Rhamphini) on Erythroxylum subsessile (Erythroxylaceae) with a description of the new species
Calculating Ensemble Averaged Descriptions of Protein Rigidity without Sampling
Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG) algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG) that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars) that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability
Spatial distribution of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) larvae in three scales
Functional morphology of the cranio-mandibular complex of the Guira cuckoo (Aves)
The cranio‐mandibular complex is an important structure involved in food capture and processing. Its morphology is related to the nature of the food item. Jaw muscles enable the motion of this complex and their study is essential for functional and evolutionary analysis. The present study compares available behavioral and dietary data obtained from the literature with novel results from functional morphological analyses of the cranio‐mandibular complex of the Guira cuckoo (Guira guira) to understand its relationship with the zoophagous trophic habit of this species. The bite force was estimated based on muscle dissections, measurements of the physiological cross‐sectional area, and biomechanical modeling of the skull. The results were compared with the available functional morphological data for other birds. The standardized bite force of G. guira is higher than predicted for exclusively zoophagous birds, but lower than for granivorous and/or omnivorous birds. Guira guira possesses the generalized jaw muscular system of neognathous birds, but some features can be related to its trophic habit. The external adductor muscles act mainly during food item processing and multiple aspects of this muscle group are interpreted to increase bite force, that is, their high values of muscle mass, their mechanical advantage (MA), and their perpendicular orientation when the beak is closed. The m. depressor mandibulae and the m. pterygoideus dorsalis et ventralis are interpreted to prioritize speed of action (low MA values), being most important during prey capture. The supposed ecological significance of these traits is the potential to widen the range of prey size that can be processed and the possibility of rapidly capturing agile prey through changes in the leverage of the muscles involved in opening and closing of the bill. This contributes to the trophic versatility of the species and its ability to thrive in different habitats, including urban areas.Fil: Pestoni, Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Degrange, Federico Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Tambussi, Claudia Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Demmel Ferreira, María Manuela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Tirao, German Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin
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