Modes Of Capture Research Articles

Decapod crustaceans used as food by the Yanomami Indians of the Balawa-ú village, State of Amazonas, Brazil

The Yanomami are a group of South American Indians that live in the rainforest along the borderlands of Brazil and Venezuela. They depend on hunting, gardening and wild food for survival; crustaceans are a highly prized food item in their diet. Taxonomical and ethnozoological aspects of the Yanomami Indians of the Balawa-ú village, state of Amazonas, Brazil, related to the crustaceans are described. Information and specimens were obtained from August to December, 2003. Interviews were conducted with residents of the village and focused on questions about species exploited, indigenous names, modes of capture and use of the species. One shrimp species of the family Palaemonidae (Macrobrachium brasiliense) and two crab species of Trichodactylidae (Sylviocarcinus pictus, Valdivia serrata) as well as two of Pseudothelphusidae (Fredius fittkaui, F. platyacanthus) were recorded. The indigenous names applied to these species are: shuhu, for shrimp, oko and peimatherimi for each of the two pseudothelphusid crabs, and hesiki tôtôrema for both trichodactylid crabs.

Freehand three‐dimensional ultrasound in the diagnosis of fetal anomalies

Purpose: To determine the clinical impact and additional information of freehand three‐dimensional ultrasound (3DUS) in the diagnosis of fetal anomalies compared to two‐dimensional ultrasound (2DUS).Methods: We studied a total of 146 anomalies found in 95 fetuses. In all of them the fetal anomaly was first assessed by 2DUS, and then by freehand 3DUS. According to the fetal anomaly, fetal or maternal conditions, one or more of the following modes of data capture were employed: volume capture (n = 42 anomalies), static capture (n = 21 anomalies), and free style capture (n = 83 anomalies), then the most suitable screen presentation was used. Clinical impact, fetal outcome and additional information were determined in all cases.Results: Freehand 3DUS images provided additional information only in three anomalies (2%) compared with 2DUS, were equivalent in 132 anomalies (90%), and were disadvantageous in 11 anomalies (8%) In most cases, when the anomalies were well visualized by 2DUS, the 3DUS images added no further information. In none of the cases the 3DUS changed the clinical management. Furthermore, all files obtained by 3DUS were more advantageous in term of post‐processing capabilities, manipulation of images by multiples physician and teaching activities compared with 2DUS.Conclusions: The different freehand 3DUS modalities were diagnostic equivalent to 2DUS in the majorities of the clinical cases and has no additional clinical impact on patient management. The most important advantages were related to the post‐processing capabilities.

F73New modes of capture by freehand three‐dimensional ultrasound in the prenatal diagnosis of fetal anomalies

BackgroundThe aim of this study was to see the contribution of three different modes of capture of data by the freehand three‐dimensional ultrasound (3D US) in the prenatal diagnosis of fetal anomalies.MethodWe studied a total of 34 pregnant women. In all of them a fetal anomaly was previously assessed by 2D US. Planar US probes and a 3D software (3D‐ViewTM) were used on a digital Gaia 8800 scanner. Three modes of data capture were employed: volume capture (to capture a volume), static capture (to capture motion; a combination of B‐mode and M‐mode), and free style capture (to capture a big region of interest; ROI), then the most suitable screen presentation was used according to the mode of capture.ResultsWe found a total of 41 anomalies on 34 fetuses which are: Heart (17), abdomen (8), central nervous system (6) and miscellaneous (10). We were able to see all anomalies previously detected by 2D US. By using volume capture and rendering image we were able to detect also anomalies of fingers and face, no previously detected by 2D. However volume capture was the most difficult mode to perform. Static capture was the most suitable to study fetal heart malformations (as A‐V canal) and arrhythmias. Free style capture give us a B‐mode digital video of the ROI (hydrocephalus, spina bifida, gastroschisis, omphalocele, adominal cysts, kidney malformations). Good pictures by using the last two modes of capture were easy to obtain. We also benefit of all the advantages of using digital technology, like to have the information as a virtual patient.ConclusionThe appropriate use of different modes of capture of data by free hand 3D US in combination with 2D US gives a new perspective of using this new technology in the diagnosis of fetal anomalies.

Ozonolyses of 3-Benzoyloxy- and 3-Trimethylsiloxy-Substituted 2-Phenylindenes in Methanol: Substituent-Dependent Modes of Capture of the Carbonyl Oxide Intermediates by the Solvent.

Ozonolyses of 3-Benzoyloxy- and 3-Trimethylsiloxy-Substituted 2-Phenylindenes in Methanol: Substituent-Dependent Modes of Capture of the Carbonyl Oxide Intermediates by the Solvent.

Variation in the feeding kinematics of mole salamanders (Ambystomatidae:Ambystoma)

High-speed cinematography was used to investigate the prey-capture kinematics of six species of mole salamanders (Ambystomatidae). We compared the feeding behavior of the subgenus Ambystoma (A. californiense and A. macrodactylum) with that of the subgenus Linguaelapsus (A. mabeei, A. texanum, A. annulatum, and A. cingulatum). Prey capture by all six species is characterized by a 3-part gape cycle (a period of rapid mouth opening prior to extraoral tongue protraction, followed by a period of relatively stable gape angle during extraoral tongue protraction and retraction, followed by a period of rapid mouth closure), a tongue-extension cycle (protraction and retraction), and anterior head–body displacement. Among the six species, two distinct modes of prey capture are evident: (1) the Ambystoma mode (A. californiense, A. macrodactylum, A. mabeei, and A. texanum), and (2) the Linguaelapsus mode (A. annulatum and A. cingulatum). Most differences in prey-capture kinematics between the two modes are primarily differences of degree rather than the addition or loss of unique behaviors, and include a general reduction in the gape angles and a general increase in the elapsed times associated with specific events in the Linguaelapsus mode. We hypothesize that these differences are primarily the result of a prolonged period of tongue protraction in the Linguaelapsus mode during which the glandular tongue pad is fitted to the prey. In addition to differing from each other, the gape profiles of the ambystomatid subgenera differ markedly from the 4-part gape profiles of plethodontids and salamandrids.

Direct estimates of multi-mesh gillnet selectivity to Oreochromis shiranus chilwae

The selectivity of multi-mesh monofilament nylon gillnets to Oreochromis shiranus chilwae was estimated directly by gillnetting in a small reservoir containing a population marked by size class. Numbers in each size class were estimated using the adjusted Petersen estimate. Pearson Type I curves were fitted to plots of selectivity against the fish length/mesh perimeter ratio, for two modes of capture: wedging and tangling. The generality of the selectivity curves is tested and discussed. The tangling component of the selectivity was unimportant, and for many applications the selectivity curves may be approximated by normal curves obtainable through indirect methods. However, the increase in the amplitude of the curves with mesh size, deserves further study.

Direct estimates of multi‐mesh gillnet selectivity to Oreochromis shiranus chilwae

The selectivity of multi‐mesh monofilament nylon gillnets to Oreochromis shiranus chilwae was estimated directly by gillnetting in a small reservoir containing a population marked by size class. Numbers in each size class were estimated using the adjusted Petersen estimate. Pearson Type I curves were fitted to plots of selectivity against the fish length/mesh perimeter ratio, for two modes of capture: wedging and tangling. The generality of the selectivity curves is tested and discussed. The tangling component of the selectivity was unimportant, and for many applications the selectivity curves may be approximated by normal curves obtainable through indirect methods. However, the increase in the amplitude of the curves with mesh size, deserves further study.

Particle Captures and the Method of Suspension Feeding by Echinoderm Larvae.

Motivated by discrepancies between two recent descriptions of the suspension-feeding mechanism employed by echinoderm larvae, I describe particle captures by the larvae of seven species of temperate eastern Pacific echinoderms from four classes. When videotape recordings of free-swimming larvae clearing plastic spheres from suspension were analyzed, two modes of particle capture were observed to operate. The majority of captured spheres were caught at the peripheral ciliated band and then transported to the mouth, often by repeated capture on portions of the band progressively nearer to the mouth. This description is consistent with the ciliary reversal model of suspension feeding described by R. R. Strathmann. A small minority of captured spheres followed broad, curving paths directly into the larval mouth without interception at the ciliated band. These particle paths resemble those described by T. H. J. Gilmour. The videotape recordings also permitted a quantitative comparison of suspension feeding by these larvae. Several aspects of this behavior varied among developmental stages or among types of larvae, including: the distribution of particle captures among different segments of the ciliated band, the number of captures for single particles en route to the mouth, and the frequency of particles lost after initial capture. This variation raises a number of questions regarding the feeding performance of different larval species and the efficacy of these different larvae as elements of a reproductive strategy.

Direct and Indirect Estimation of Gillnet Selection Curves of Atlantic Herring (Clupea harengus harengus)

Length-specific selection curves for Atlantic herring (Clupea harengus) were calculated for a series of gillnets ranging in mesh size from 50.8 to 76.2 mm (stretched measure) using Holt's (1963) model (ICNAF Spec. Publ. 5: 106–115). These curves were than compared with direct estimates of length-specific selectivity obtained from a comparison of gillnet catch length frequencies with population length composition data as determined from acoustic surveys. Selection curves calculated indirectly using the Holt model were unimodal and congruent. The empirical selection curves however were multimodal and fishing power varied with mesh size. These differences in selectivities were due to the fact that herring were caught not only by wedging at the maximum girth but also at other body positions such as the gills and snout. Each of these modes of capture have different length-specific selectivity characteristics and, since the relative contributions of the different modes of capture varied both between nets and annually, the selection curve of herring for a particular mesh size is not unique. It can however be reasonably approximated when girth is used as the selection criterion. Direct empirical selectivities are therefore recommended when interpreting population parameters from herring gillnet catch data.

Electron addition to 5-bromo-5-nitro-1,3-dioxanes

Studies using e.s.r. spectroscopy show a remarkable range of possible modes of electron capture by 5-bromo-5-nitro-1,3-dioxanes; capture in CBr bonds, capture at nitro groups, dissociative capture with loss of bromide anions, and dissociative capture with loss of nitrite anions.

Transition from diffusive to ballistic capture related to hydrogen incorporation in amorphous silicon

Abstract We have shown in previous work that, in triode d.c. sputtered amorphous silicon, the value of the capture cross-section σ of deep gap states depends strongly on the hydrogen content of the material. In this Letter, we analyse the influence of such an effect on the transport properties of a set of samples whose hydrogen content C H varies between 8 and 20%. For this purpose, we have measured at room temperature the mobility–lifetime product for electrons, μnτn, the density of states at the Fermi level N(EF) and the defect density N s derived from photothermal deflection spectroscopy experiments. Log–log plots of the μnτn N(E F) and μnτn N s products against σ show two regimes with a transition corresponding to a hydrogen content of about 12%. These two regimes are related to different modes of capture controlled either by a diffusive process (low C H) or by a ballistic process (high C H). From the transition between the two regimes, we calculate that the electron scattering length is of the order ...

A laboratory study of optimal behaviour and the costs of net construction by Polycentropus Havomaculatus (Insecta: Trichoptera: Polycentropodidae)

Metabolic rates of Polycentropus flavomaculatus larvae in a flow‐through respirometer at 15°C were 17 % higher during net spinning than while larvae were resting. The energy content of net silk and caddisfly tissues, obtained by bomb calorimetry, were 23–367 J mgAFDW‐1 and 25–715 J mg AFDW‐1, respectively. Total cost of net construction for an ‘average’ 5th instar larva (2–808 mg dry wt) was 0124 J as silk (75–8 % of total cost) and 0030 J as increased activity over the 293‐minute building period at 15°C.A significant cost jn net building was demonstrated by larvae which were forced to rebuild their nets daily. They lost more weight than larvae which were forced to rebuild every second day; undisturbed (starved) larvae lost least weight. The weight of nets which were rebuilt daily declined over successive constructions, but net allocation (net weight/larval weight) remained rather constant. The major energetic expense of undisturbed larvae was routine metabolism, whilst that of the daily rebuilders was silk synthesis.Feeding regime had a marked influence on net construction, and ad libitum fed larvae built larger nets than those fed every second day; starved larvae built the smallest nets. Food capture was apparently linked to the initiation of construction behaviour and thus a more liberal feeding regime was associated with larger nets.The energy gain (food intake –costs of metabolism and silk synthesis) of ad libitum fed larvae was greater than that of animals fed every second day, and the cost/benefit function for both groups declined throughout the experiment. While each meal was associated with additional net‐spinning costs, over time, the animals tended towards greater energetic economy.Prior feeding regime had no effect on the weight of nets built subsequently; nets were spun without reference to expectation of prey capture. Prior feeding regime had a significant effect on giving‐up time, and those animals with previous experience of high prey capture rates abandoned nets sooner than larvae which had experienced a lower rate of encounter. However, the giving‐up time of all treatment groups (< 50 % given‐up after 30 days) was longer than previously reported for polycentropodids.Polycentropus flavomaculatus larvae have resting metabolic rates lower than those of ‘normal’ poikilotherms and spiders, but similar to those of ant lions. These differences are correlated with modes of food capture, and allow P. flavomaculatus to endure periods of food scarcity.

Modes of algal capture by the freshwater copepod Diaptomus sicilis and their relation to food‐size selection1,2

High‐speed motion pictures (500 frames s−1) of tethered Diaptomus sicilis feeding in suspensions of Chlamydomonas spp. of three different sizes at three different concentrations (0.3, 1.0, and 3.0 mm3 liter−1), showed two modes of feeding: a passive mode in which algae flowed into the space between the left and right second maxillae and an active mode in which the second maxillae or second maxillae plus maxilliped made large amplitude flaps to bring in the cell. Cells ≤4 µm in diameter were always captured passively, and cells ≥6 µm were captured both actively and passively. Active captures were 18% of total captures for the medium‐sized (6 µm) algae and 36% for the large (12 µm) algae. During passive captures, algae usually flowed through the space between the left and right second maxillae rather than being caught on the setules; thus, the leaky‐sieve model of particle retention does not apply for passive captures by D. sicilis. Except for brief interruptions to actively capture a large alga nearby, the second maxillae of D. sicilis oscillated continuously at low amplitude at all times during feeding, in marked contrast to the marine copepods Eucalanus and Paracalanus that vibrated their second maxillae to enhance capture in monocultures of small algae but not large algae. These observations explained both the shape of the curve of selectivity vs. particle size for D. sicilis and its relative invariance. Analyses of feeding mechanisms and the water currents around Diaptomus showed that, in contrast to Eucalanus and Paracalanus, Diaptomus is specialized for capturing small particles, which may be a more important food in freshwater than in marine environments.

Modes of cell capture in calanoid copepods1

High‐speed cinematography was used to observe adult female copepods feeding in pure cultures of roughly spherical algal cells ranging from 4.5 to 22.0 µm in diameter. Eucalanus pileatus and Paracalanus parvus detect and handle individual cells as small as 12 µm. Continuous low amplitude movement of the second maxillae and combing of the appendages is used by E. pileatus to capture cells smaller than the 12‐µm sensitivity threshold. Different energetic costs are probably associated with capturing small and large cells, and the probability of copepods encountering large cells should be greatly increased due to remote detection. The above suggests that descriptions of selective feeding in grazing trials using Coulter Counter data are influenced by the size above which the copepods can detect individual cells and by the proportions of the pregrazing particle spectrum larger and smaller than this threshold.

Negative Ions of Polyatomic Molecules

In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules area discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron affinity"), and the basic and the applied significance of negative-ion studies.

Negative ions of polyatomic molecules.

In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules area discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron affinity"), and the basic and the applied significance of negative-ion studies.

Radiative capture and recombination in electron-atom collisions

A comprehensive theory of electron scattering from atoms and ions at high energies is formulated, incorporating the coupling of the scattering system to the radiation field. In particular, the photocapture process is discussed in detail, which can proceed either by a direct radiative capture or by dielectronic recombination following a radiationless capture into excited states. The latter process involves a collisional excitation of the inner-shell electrons of the target, followed by radiative decay of that excited state. The required sum over excitation probabilities to all the allowed bound states is estimated using the semiclassical projection operators and the single-particle model for the target system. A preliminary estimate of the cross sections for these modes of capture is obtained for the case of a hot-electron plasma interacting with highly ionized impurity ions.

The Carbon Balance of Plants

There has been considerable recent interest in the assessment of the en­ ergy allocation of plants (38, 50, 52). It is likely that through a quantitative understanding of how different plants gain and allocate their resources it will be possible to make predictions as to their success in any given physical envi­ ronment in combination with any competitor and predator. We are still far from this reality. However, as a contribution toward this goal, this review seeks to gather the available. information on the various evolutionary strate­ gies which plants have evolved to gain energy and to account for the numer­ ous ways in which this energy is utilized to meet the demands of the environ­ ment, as well as to successfully produce progeny. To date, studies which have considered allocation have generally been at a rather gross level-e.g., reproductive versus nonreproductive (38), roots versus shoots (117), and photosynthetic versus nonphotosynthetic tissue (86). A study by Harper & Ogden (52) has attempted, however, to account in somewhat more detail for the various sources of energy allocation. To account in more detail for energy gain in allocation and for its even­ tual loss through a variety of routes, the approach that will be used here is the capture of carbon by plants and its SUbsequent diversion into various products which perform a multiplicity of functions. Carbon is the vehicle by which organisms store and transfer energy by chemical binding. This device enables the utilization of a large reservoir of physiological and ecological data into a single coherent body. However, it becomes rather clear that the total information required for any given plant simply does not exist. Thus, this review unfortunately can represent only a composite picture of the gen­ realized routes of carbon movement in plants. It does, however, call attention to the continual partitioning of resources and the multiplicity of carbon path­ ways. Emphasis is placed on the modes of capture of carbon. Hopefully, this analysis will stimulate studies which will provide, for a given series of bio­ types, the total information on carbon gain, use, and loss, so that quantitative models can be derived relating these to shortand long-term environmental influences.

Aerobraking as a potential planetary capture mode.

The synthesis of manned aerobraking spacecraft for missions to Mars and Venus is described. Pertinent data derived from performance, weights, heating, and heat shield design analyses conducted to support the synthesis are presented. The sequential approach that was used, in which aerobraker mission-system requirements were establised and candidate vehicle arrangements were prepared, is discussed. Sensitivity analyses and selected configurations are presented along with the evolved modular approach to aerobraker spacecraft design. Considerable commonality between the Mars and Venus vehicles and requirements for elliptical parking orbit missions using modular designs is shown. Comparisons of the aerobraking and retrobraking modes of orbital capture at Mars and Venus are presented to show that a chemically (FLOX/CELi) propelled aerobraker vehicle system requires less mass on Earth orbit than a nuclear (LH^) retrobraker for all mission opportunities from 1980 to 2000.

The Division of Labor is Limited by the Extent of the Market

The Division of Labor is Limited by the Extent of the Market