501 research outputs found
Interaction Between Visual and Phonotactic Orientation During Flight in \u3ci\u3eMagicicada Cassini\u3c/i\u3e (Homoptera: Cicadidae)
Visual and phonotactic orientation often occur simultaneously in diurnal cicadas. and these animals generally have their largest sensory elaboration in eyes and hearing organs. Phonotactic orientation occurs principally during flight. Males and females of Magicicada cassini commonly perform low- altitude « 5 m) and short-distance « 15 m) flights in their natural habitat at flight speeds of 3 to 6 m/s. During flight, the long body axis is tilted 10° to Q , head upward. Wing beat frequencies of tethered animals at 24° to 26°C averaged 28.8 Hz. Body temperature in the field for flying individuals aver- aged 4.6°C above ambient.
Compound eyes of females possess about 7% more facets than males, and the binocular field of view for both is especially expanded dorsa-frontally, frontally, and fronto-ventrally. The role of vision for phonoresponses, and in flight and landing behavior. was studied in nature by comparing controls with cicadas with eyes partly to completely covered with aluminum paint. Cicadas with their three ocelli covered behaved like controls and exhibited low-altitude and short-distance flights with landings on neighboring shrubs, as did cicadas with only both caudal halves or both dorsal halves of the compound eyes covered. Those with both compound eyes covered completely (with or without additionally covering the three ocelli) flew to higher altitudes and for longer distances. Higher and longer flight courses were also seen in cicadas (A) with only one compound eye covered. which in addition circled during walking and flight toward the side of unrestricted vision, (B) with both frontal or both ventral halves of their compound eyes covered. and (C) with either the binocular or monocular fields of the eyes covered. Thus, the paired fronta-antero-ventral regions of the compound eyes provide visual information for habitat-dependent low-altitude flights and landings.
Females with intact compound eyes and ocelli responded to playbacks of just the frequency/intensity sweep at the end of the buzz in calling songs of a male by flying within 1.2 m above the ground and landing on a nylon screen- covered small bush directly above the loudspeaker from distances of 2 to 8 m. mostly from lower vegetation. Males that were blinded, or blinded and deafened, sang less and flew less than normal males. However. they performed all of those behaviors, and all also walked and fed.
Periodical cicadas (Magicicada, Tibicininae) are known for synchronized adult emergence and noisy aggregations of millions of individuals of three intermingled species in each brood population (Alexander and Moore 1962). Broods are isolated geographically and chronologically, such that in some years no periodical cicada adults emerge, and most areas of the eastern United States have only one brood population appearing as adults at intervals of either 13 or 17 years. In all Magicicada species, daily flights affect spacing and aggregation of both sexes during feeding, chorusing, mating, and ovipositing. Flights are mediated by both acoustical and visual cues. Each species in these aggregations establishes mating leks. These aggregations continue to mix, every day and unpredictably, during the emergence period. Toward the end of the reproductive season, males die sooner than females, leading to little or no chorusing, and then females disperse progressively further from the lek sites. The cohesive effect of the acoustical cues of chorusing males on these cicada populations is obvious.
Both sexes of all six species of periodical cicadas live and feed on shrubs and trees of different species, sizes, and shapes, and females lay eggs in their living twigs. Their niches overlap almost completely, the three species of 13 year or 17-year cicadas being separated principally by diurnal acoustic behavior leading to aggregation sites that change every day and are seldom exclusive to a single Magicicada species. Adults frequently change location in these complex visual environments by short-distance and low-altitude flights. which we call bush-hopping. These flights are associated with sound communication and reproductive activities and are most commonly observed during bright sunlight and at ambient temperatures above 25°C with little wind (Alexander and Moore 1958,1962; Dunning et al. 1979). Otte (1990) and Toms (1992) discuss the common correlation between hearing and flying in orthopteroid insects, interactions basically similar to those found in cicadas. The present paper describes the interaction of vision (compound eyes and ocelli) and phonoresponses of males and females of Magicicada cassini (Fisher) in walking, but especially in flight and landing behavior, within a natural habitat
Efficient balancing of q-ary sequences with parallel decoding
Abstract: Balancing of q-ary sequences, using a generalization of Knuth’s efficient parallel balancing scheme, is considered. It is shown that the new general scheme is as simple as the original binary scheme, which lends itself to parallel decoding of the balanced sequences
The nematocyst extract of Hydra attenuata causes single channel events in lipid bilayers
Weber J, Schürholz T, Neumann E. The nematocyst extract of Hydra attenuata causes single channel events in lipid bilayers. Toxicon. 1990;28(4):403-409
Prefixless q-ary balanced codes with fast syndrome-based error correction
Abstract: We investigate a Knuth-like scheme for balancing q-ary codewords, which has the virtue that look-up tables for coding and decoding the prefix are avoided by using precoding and error correction techniques. We show how the scheme can be extended to allow for error correction of single channel errors using a fast decoding algorithm that depends on syndromes only, making it considerably faster compared to the prior art exhaustive decoding strategy. A comparison between the new and prior art schemes, both in terms of redundancy and error performance, completes the study
Concatenated permutation block codes based on set partitioning for substitution and deletion error-control
A new class of permutation codes is presented where, instead of considering one permutation as a codeword, codewords consist of a sequence of permutations. The advantage of using permutations, i.e. their favourable symbol diversity properties, is preserved. Additionally, using sequences of permutations as codewords, code rates close to the optimum rate can be achieved. Firstly, the complete set of permutations is divided into subsets by using set partitioning. Binary data is then mapped to permutations from these subsets. These permutations, together with a parity permutation, will form the codeword. Two constructions will be presented: one capable of detecting and correcting substitution errors and the other capable of detecting and correcting either substitution or deletion errors
Serum inhibin B as a marker of spermatogenesis
Inhibin B is produced by Sertoli cells, provides negative feedback on FSH
secretion, and may prove to be an important marker for the functioning of
seminiferous tubules. The purpose of the present study was to examine the
relationship between the spermatogenic function of the testis of
subfertile men and the plasma concentrations of inhibin B and FSH. These
parameters were estimated in a group of 218 subfertile men. Serum inhibin
B levels were closely correlated with the serum FSH levels (r = -0.78, P <
0.001), confirming the role of inhibin B as feedback signal for FSH
production. The spermatogenic function of the testis was evaluated by
determining testicular volume and total sperm count. Inhibin B levels were
significantly correlated with the total sperm count and testicular volume
(r = 0.54 and r = 0.63, respectively; P < 0.001). Testicular biopsies were
obtained in 22 of these men. Inhibin B was significantly correlated with
the biopsy score (r = 0.76, P < 0.001). Receiver operating characteristic
analysis revealed a diagnostic accuracy of 95% for differentiating
competent from impaired spermatogenesis for inhibin B, whereas for FSH, a
value of 80% was found. We conclude that inhibin B is the best available
endocrine marker of spermatogenesis in subfertile men
Improvement of sperm count and motility after ligation of varicoceles detected with colour Doppler ultrasonography
Development of a multiplex fluorescence immunological assay for the simultaneous detection of antibodies against Cooperia oncophora, Dictyocaulus viviparus and Fasciola hepatica in cattle
Background A major constraint for the effective control and management of
helminth parasites is the lack of rapid, high-throughput, routine diagnostic
tests to assess the health status of individual animals and herds and to
identify the parasite species responsible for these helminthoses. The
capability of a multiplex platform for the simultaneous detection of three
pasture associated parasite species was evaluated and compared to existing
ELISAs. Methods The recombinant antigens 14.2 kDa ES protein for Cooperia
oncophora, major sperm protein for Dictyocaulus viviparus and Cathepsin L1 for
Fasciola hepatica were recombinantly expressed either in Escherichia coli or
Pichia pastoris. Antigens were covalently coupled onto magnetic beads. Optimal
concentrations for coupling were determined following the examination of serum
samples collected from experimentally mono-infected animals, before and after
their infection with the target species. Absence of cross-reactivity was
further determined with sera from calves mono-infected with Haemonchus
contortus, Ostertagia ostertagi and Trichostrongylus colubriformis.
Examination of negative serum samples was characterised by low median
fluorescence intensity (MFI). Results Establishment of the optimal serum
dilution of 1:200 was achieved for all three bead sets. Receiver Operating
Characteristic analyses were performed to obtain cut-off MFI values for each
parasite separately. Sensitivity and specificity at the chosen cut-off values
were close to, or 100 % for all bead sets. Examination of serum samples
collected on different days post infection from different animals showed a
high reproducibility of the assays. Serum samples were additionally examined
with two already established ELISAs, an in-house ELISA using the recombinant
MSP as an antigen and a DRG ELISA using Cathepsin L1 for liver fluke. The
results between the assays were compared and kappa tests revealed an overall
good agreement. Conclusions A versatile bead-based assay using fluorescence
detection (xMAP® technology) was developed to simultaneously detect antibodies
against C. oncophora, D. viviparus and F. hepatica in cattle serum samples.
This platform provides rapid, high-throughput results and is highly sensitive
and specific in comparison to existing serological as well as coproscopical
diagnostic techniques
The BBCH system to coding the phenological growth stages of plants – history and publications –
Die Entwicklungsstadien der wichtigsten Kulturpflanzen wurden in den vergangenen 19 Jahren von zahlreichen Wissenschaftlern nach den Prinzipien der erweiterten BBCH-Skala beschrieben. Die BBCH-Skalen sind inzwischen weltweit bekannt und werden von Wissenschaft, Administration und Praxis in Landwirtschaft und Gartenbau ebenso genutzt, wie in der Phänologie als integrative Wissenschaft im Bereich Umwelt, Meteorologie und Klimatologie.
Diese Tatsache weist darauf hin, dass Zielsetzung und Hoffnung, die seit dem Beginn der Arbeit damit verbunden waren, sich erfüllt haben. Die BBCH-Skalen haben sich als hilfreich und praktisch erwiesen. Das Ziel, die Harmonisierung in der Anwendung von Dezimalcodes für die Beschreibung der phänologischen Entwicklungsstadien von Kulturpflanzen und Unkräutern herbeizuführen, wurde erreicht. Sie erfüllten auch die Hoffnung der Initiatoren, damit zur Verbesserung der internationalen agrarwissenschaftlichen und interdisziplinären Kommunikation beizutragen.
In der vorliegenden Arbeit soll die Geschichte der BBCH-Skalen aufgezeigt werden, weil diese Einblick in die Hintergründe ihrer Entstehung und Entwicklung erlaubt. Alle Original-Publikationen werden mit ihren Literaturquellen zusammenfassend dargelegt. Die Arbeit soll die unterschiedliche Nutzung der BBCH-Skalen in den verschiedenen wissenschaftlichen Disziplinen dokumentieren. Es soll deutlich werden, dass der weltweite Erfolg der BBCH-Skalen vielen Wissenschaftlern rund um den Globus zu verdanken ist.The growth stages of development of many cultivated plants have been described by numerous scientists according to the principles of the extended BBCH scale within the last 19 years. The BBCH scales are now well- known worldwide and are used by research, administration and practise in agriculture and horticulture, as in the phenology as an integrative science in environment, meteorology and climatology.
This fact indicates that the basic objectives and hope have been reached, justifying the practical approach taken by the authors of this scale. The BBCH scale is a contribution to improve the communication between different groups of scientists and to allow the interchange of data and scientific results in a transparent way. The BBCH scales have turned out helpful and practical. The aim to cause the harmonisation in the application of decimal codes for the description of the phenological growth stages of plants and weeds was reached. They also fulfilled the hope of the initiators to contribute with it to the improvement of the international agrarian-scientific and interdisciplinary communication.
This paper will describe the history and background of the BBCH scales. The original publications are described and explained with reference of the original literature sources. The paper will describe the different area of use of the scales and list the different scientific disciplines using them. The worldwide success of the BBCH scales is the work of many scientists around the globe
- …