Population cytogenetics of Chorthippus vagans. II. Reduced meiotic transmission but increased fertilization by males possessing a supernumerary chromosome

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 285-291 ◽  
Author(s):  
Josefa Cabrero ◽  
Juan Pedro M. Camacho
Keyword(s):  
Sexual Selection ◽  
Mass Culture ◽  
Low Frequency ◽  
Phenotypic Selection ◽  
B Chromosome ◽  
Supernumerary Chromosome ◽  
Relative Fitness ◽  
C Banding ◽  
Meiotic Transmission ◽  
The One

A submetacentric B chromosome was present at a low frequency (ca. 4%) in a natural population of the grasshopper Chorthippus vagans. Its heterochromatic nature is shown by its positive heteropycnosis during first meiotic prophase and by its response to C-banding. As its C-banding pattern and the meiotic autopairing of its two arms both demonstrate, it appears to have been derived from a metacentric iso-B chromosome by means of a pericentric inversion. The frequencies of equational division of the B univalents and the formation of abnormal gametes were significantly different between the 2 one B males found. A causal relationship is demonstrated between the equational division of the B at anaphase I and the formation of spermatid micronuclei, which can be assumed to contain B chromosomes that are being eliminated. Such B elimination was higher in male no. 2 than in male no. 37. The estimated B-transmission frequency was 0.28 for male no. 2 and 0.46 for male no. 37. The presence in the same population of polymorphisms for the M4 and M7 autosomes made it possible to determine the specific parents for four egg pods containing the B chromosome produced in a mass culture using wild-caught individuals. From this we calculate the actual transmission of the B by the one B males to be 0.27 for male no. 2 and 0.44 for male no. 37, which agrees with their respective estimated transmission frequencies. The relative fitness of zero B and one B males was calculated in terms of their viability and fertility components. While viability was lower for one B individuals, their fertility was much higher than that of zero B males. Indeed, sexual selection in favour of one B males was sufficiently high to counteract both the reduced transmission of the B by one B males and the phenotypic selection against one B zygotes. Key words: Chorthippus, meiotic drag, supernumerary chromosome, B chromosome, sexual selection.

scholarly journals Posturography with head movements in the assessment of balance in chronic unilateral vestibular lesions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Magdalena Janc ◽  
Mariola Sliwinska-Kowalska ◽  
Piotr Politanski ◽  
Marek Kaminski ◽  
Magdalena Jozefowicz-Korczynska ◽  
...  
Keyword(s):  
High Reliability ◽  
Low Frequency ◽  
Random Order ◽  
Head Movements ◽  
Canal Paresis ◽  
Eyes Closed ◽  
Static Posturography ◽  
Unstable Surface ◽  
Novel Method ◽  
The One

AbstractThe aim of our study was to validate the method of head-shake static posturography (HS-posturography) in healthy individuals and to establish the value of this novel method in the diagnostics of patients with unilateral vestibular lesion (UV). The study included 202 participants divided into two groups, one consisting of 133 patients with canal paresis CP > 19% and one of 69 healthy subjects. Participant was tested according to the standard protocol of static posturography (SP), and with head movements of 0.3 Hz (HS 40), 0.6 Hz (HS 70) in random order controlled by a metronome. HS-posturography revealed a similar repeatability and internal consistency as the standard posturography. In patients with UV, 4th condition revealed higher sensitivity (74%) and specificity (71%) in HS 40 than in the standard posturography (67%, 65% respectively) and HS 70 (54%, 70% respectively). Static posturography and HS- posturography revealed a high reliability of the testing method. The head movements added to static posturography improve the sensitivity and specificity of the method in group with vestibular impairment. The most important test for that purpose seems to be the one on unstable surface with the eyes closed, with low frequency of head movements.

scholarly journals Estimation of the Noise Source Level of a Commercial Ship Using On-Board Pressure Sensors

2021 ◽  
Vol 11 (3) ◽  
pp. 1243
Author(s):  
Hongseok Jeong ◽  
Jeung-Hoon Lee ◽  
Yong-Hyun Kim ◽  
Hanshin Seol
Keyword(s):  
Noise Source ◽  
Pressure Sensors ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Source Strength ◽  
Recording Time ◽  
Source Level ◽  
The One ◽  
Hydrophone Array ◽  
Good Agreement

The dominant underwater noise source of a ship is known to be propeller cavitation. Recently, attempts have been made to quantify the source strength using on-board pressure sensors near the propeller, as this has advantages over conventional noise measurement. In this study, a beamforming method was used to estimate the source strength of a cavitating propeller. The method was validated against a model-scale measurement in a cavitation tunnel, which showed good agreement between the measured and estimated source levels. The method was also applied to a full-scale measurement, in which the source level was measured using an external hydrophone array. The estimated source level using the hull pressure sensors showed good agreement with the measured one above 400 Hz, which shows potential for noise monitoring using on-board sensors. A parametric study was carried out to check the practicality of the method. From the results, it was shown that a sufficient recording time is required to obtain a consistent level at high frequencies. Changing the frequency resolution had little effect on the result, as long as enough data were provided for the one-third octave band conversion. The number of sensors affected the mid- to low-frequency data.

scholarly journals Handling Nonlinearity in an Ensemble Kalman Filter: Experiments with the Three-Variable Lorenz Model

2012 ◽  
Vol 140 (8) ◽  
pp. 2628-2646 ◽  
Author(s):  
Shu-Chih Yang ◽  
Eugenia Kalnay ◽  
Brian Hunt
Keyword(s):  
Kalman Filter ◽  
Ensemble Kalman Filter ◽  
Linear Models ◽  
Low Frequency ◽  
Lorenz Model ◽  
Outer Loop ◽  
Nonlinear Growth ◽  
Ensemble Mean ◽  
Ensemble Transform Kalman Filter ◽  
The One

Abstract An ensemble Kalman filter (EnKF) is optimal only for linear models because it assumes Gaussian distributions. A new type of outer loop, different from the one used in 3D and 4D variational data assimilation (Var), is proposed for EnKF to improve its ability to handle nonlinear dynamics, especially for long assimilation windows. The idea of the “running in place” (RIP) algorithm is to increase the observation influence by reusing observations when there is strong nonlinear error growth, and thus improve the ensemble mean and perturbations within the local ensemble transform Kalman filter (LETKF) framework. The “quasi-outer-loop” (QOL) algorithm, proposed here as a simplified version of RIP, aims to improve the ensemble mean so that ensemble perturbations are centered at a more accurate state. The performances of LETKF–RIP and LETKF–QOL in the presence of nonlinearities are tested with the three-variable Lorenz model. Results show that RIP and QOL allow LETKF to use longer assimilation windows with significant improvement of the analysis accuracy during periods of high nonlinear growth. For low-frequency observations (every 25 time steps, leading to long assimilation windows), and using the optimal inflation, the standard LETKF RMS error is 0.68, whereas for QOL and RIP the RMS errors are 0.47 and 0.35, respectively. This can be compared to the best 4D-Var analysis error of 0.53, obtained by using both the optimal long assimilation windows (75 time steps) and quasi-static variational analysis.

Calculation of NQR v's and T1-1' s being proportional to T4 and T5 , respectively

1990 ◽  
Vol 45 (3-4) ◽  
pp. 536-540
Author(s):  
Mariusz Máckowiak ◽  
Costas Dimitropoulos
Keyword(s):  
Temperature Dependence ◽  
Relaxation Rate ◽  
Spin System ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Lattice Vibrations ◽  
Spin Lattice ◽  
Simplifying Assumptions ◽  
The One

Abstract The second-order Raman phonon process for a multilevel spin system is shown to give a quadru-polar spin-lattice relaxation rate T1-1varying as T5 at very low temperatures. This relaxation rate for quadrupole spins is similar to the one discussed for a paramagnetic spin system having a multilevel ground state. The temperature dependence of T1 is discussed on the basis of some simplifying assumptions about the nature of the lattice vibrations in the Debye approximation. This type of relaxation process has been observed below 20 K in tetramethylammonium hydrogen bis-trichloroacetate for the 35Cl T1-1 . Below 20 K the NQR frequency in the same crystal reveals a T4 temperature dependence due to the induced modulations of the vibrational and librational coordinates by the low-frequency acoustic phonons.

scholarly journals Diversity of and Selection Acting on CylindrospermopsincyrBGene Adenylation Domain Sequences in Florida

2011 ◽  
Vol 77 (7) ◽  
pp. 2502-2507 ◽  
Author(s):  
Mete Yilmaz ◽  
Edward J. Phlips
Keyword(s):  
United States ◽  
Low Frequency ◽  
Purifying Selection ◽  
The United States ◽  
The Other ◽  
Cylindrospermopsis Raciborskii ◽  
Adenylation Domain ◽  
Other Hand ◽  
Neutrality Tests ◽  
The One

ABSTRACTAphanizomenon ovalisporumis the only confirmed cylindrospermopsin producer identified in the United States to date. On the other hand,Cylindrospermopsis raciborskiiis a prominent feature of many lakes in Florida and other regions of the United States. To see the variation in cylindrospermopsincyrBgene adenylation domain sequences and possibly discover new cylindrospermopsin producers, we collected water samples for a 3-year period from 17 different systems in Florida. Positive amplicons were cloned and sequenced, revealing that approximately 92% of sequences wereA. ovalisporum-like (>99% identity). Interestingly, 6% of sequences were very similar (>99% identity) tocyrBsequences ofC. raciborskiifrom Australia and ofAphanizomenonsp. from Germany. Neutrality tests suggest thatA. ovalisporum-likecyrBadenylation domain sequences are under purifying selection, with abundant low-frequency polymorphisms within the population. On the other hand, when compared between species by codon-based methods, amino acids of CyrB also seem to be under purifying selection, in accordance with the one proposed amino acid thought to be activated by the CyrB adenylation domain.

scholarly journals Karyotypic diversity among three species of the genus Astyanax (Characiformes: Characidae)

2016 ◽  
Vol 76 (2) ◽  
pp. 360-366 ◽  
Author(s):  
P. B. Nishiyama ◽  
M. M. R. Vieira ◽  
F. E. Porto ◽  
L. A. Borin ◽  
A. L. B. Portela-Castro ◽  
...  
Keyword(s):  
Diploid Number ◽  
Fish Fauna ◽  
Distinct Pattern ◽  
Supernumerary Chromosome ◽  
C Banding ◽  
Incertae Sedis ◽  
Banding Analysis ◽  
Karyotypic Diversity ◽  
Karyotype Formula

Abstract The group Incertae sedis within the Characidae family currently includes 88 genera, previously included in the subfamily Tetragonopterinae. Among them is the genus Astyanax comprising a group of species with similar morphology and widely distributed in the Neotropics. Thus, the present study aimed to analyze the karyotype diversity in Astyanax species from different watersheds by conventional Giemsa staining, C-banding and fluorescence in situ hybridization (FISH rDNA 18S) probe.specimens of Astyanax aff. paranae belonging to the “scabripinnis complex”, Astyanax asunsionensis and Astyanax aff. bimaculatus were analyzed”. Two sympatric karyomorphs were observed in Astyanax.aff paranae, one of them having2n=48andthe other one with 2n=50 chromosomes. Other population of this same species also presented 2n=50 chromosomes, but differing in the karyotype formula and with macro supernumerary chromosome found in 100% of the cells in about 80%of females analyzed. Two population of A. asuncionensis and one population of Astyanax. aff. bimaculatus, also showed a diploid number of 50 chromosomes, but also differing in their karyotype formulas. Therefore, A. asuncionensis was also characterized by intraspecific chromosome diversity. The C-banding analysis was able to demonstrate a distinctable to demonstrate a distinct pattern of heterochromatin differing A. asuncionensis from Astyanax aff. paranae and Astyanax aff. bimaculatus. The supernumerary chromosome of Astyanax aff. paranae proved completely heterochromatic. Only Astyanax.aff. bimaculatus multiple showed multiple sites of nucleolar organizing regions. The other species were characterized by having a simple system of NOR. These data contributes to the know ledge of the existing biodiversity in our fish fauna, here highlighted by the inter- and intraspecific chromosomal diversity in the genus Astyanax.

scholarly journals A LIFE-HISTORY PERSPECTIVE ON SEXUAL SELECTION IN A POLYGAMOUS SPECIES

2019 ◽  
Author(s):  
Gao Ke ◽  
Michiel van Wijk ◽  
Zoe Clement ◽  
Martijn Egas ◽  
Astrid Groot
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Sperm Competition ◽  
Reproductive Output ◽  
Relative Fitness ◽  
Quadratic Model ◽  
Costs And Benefits ◽  
Bateman Gradient ◽  
Multiple Matings ◽  
Males And Females

Abstract Background Ever since Darwin, evolutionary biologists have studied sexual selection driving differences in appearance and behaviour between males and females. An unchallenged paradigm in such studies is that one sex (usually the male) signals its quality as a mate to the other sex (usually the female), who is choosy in accepting a partner. Here, we argue that in polygamous species these roles may change dynamically with the mating status of males and females, depending on direct reproductive costs and benefits of multiple matings, and on sperm competition. We test this hypothesis using a polygamous moth species, as in moths not males but females are the signalers and males are the responders. Results We found that multiple matings are beneficial as well as costly for both sexes. Specifically, the number of matings did not affect the longevity of males or females, but when paired with a new virgin mate every night for five nights, only 67% of the males and 14% of the females mated successfully in all five nights. The female’s reproductive output increased with multiple matings, although when paired with a new virgin male every night, additional matings beyond 3 decreased her reproductive output, so that the Bateman gradient for females fit a quadratic model better than a linear model. The male’s reproductive success was positively affected by the number of matings and a linear regression line best fit the data. Simulations of the effect of sperm competition showed that increasing last-male paternity increases the steepness of the male Bateman gradient and thus the male’s relative fitness gain from additional mating. Irrespective of last-male paternity value, the female Bateman gradient is steeper than the male one for up to three matings. Conclusion Our results suggest that choosiness in moths may well change throughout the mating season, with males being more choosy early in the season and females being more choosy after having mated at least three times. This life-history perspective on the costs and benefits of multiple matings for both sexes sheds new light on sexual selection forces acting on sexual signals and responses.

scholarly journals Masculinity in Indonesian Popular Culture in the Early Era of the New Order Regime

2017 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Ferry Fauzi Hermawan
Keyword(s):  
Popular Culture ◽  
Mass Culture ◽  
Male Dominance ◽  
New Historicism ◽  
New Order ◽  
The Social ◽  
The One ◽  
Sexual Object ◽  
In The Beginning ◽  
The Ideal

This study aimed to identify the forms of masculinity in the Indonesian popular culture in the beginning of New Order regime. This study was based on the two novels: Cross Mama and Kekasih-Kekasih Gelap, written by Motinggo Busye. The analysis used new historicism theory proposed by Stephen Greenblatt. The analysis also considered various cultural contexts emerged in 1970s. The results show three shared trends in the novels. The first trend shows that the masculinity tends to be represented by both men worshiping patriarchal values such as the myth of woman’s virginity and men perceiving woman as a sexual object. The second trend shows that masculinity is stereotyped based on masculinity, power, and male dominance. The third trend shows that masculinity relates to various products of mass culture at the time. This last trend shows that in that era,the ideal male figure is represented as the one who: (1) is sexually active with many women, (2) has a muscular body, (3) has a handsome look, and (4) has a financial capability. Besides the shared three trends, the result also shows that the texts in the novels do not only reflect the cultural situations in the 60’s and 70’s but also contribute in shaping the social values of the cultural situations.

scholarly journals Blooms of aberrant planktic foraminifera across the K/Pg boundary in the Western Tethys: causes and evolutionary implications

Paleobiology ◽  
2018 ◽  
Vol 44 (3) ◽  
pp. 460-489 ◽  
Author(s):  
Ignacio Arenillas ◽  
José A. Arz ◽  
Vicente Gilabert
Keyword(s):  
Environmental Changes ◽  
Low Frequency ◽  
Meteorite Impact ◽  
Planktic Foraminifera ◽  
Western Tethys ◽  
Quantitative Studies ◽  
El Kef ◽  
Abnormality Index ◽  
The One ◽  
Aberrant Tests

AbstractWe report a detailed study of the different categories and types of abnormal morphologies in planktic foraminifera recognizable in the lowermost Danian, mainly from the El Kef and Aïn Settara sections, Tunisia. Various types of abnormalities in the test morphology were identified, including protuberances near the proloculus, abnormal chambers, double or twinned ultimate chambers, multiple ultimate chambers, abnormal apertures, distortion in test coiling, morphologically abnormal tests, attached twins or double tests, and general monstrosities. Detailed biostratigraphic and quantitative studies of the Tunisian sections documented a major proliferation of aberrant planktic foraminifera (between approximately 5% and 18% in relative abundance) during the first 200 Kyr of the Danian, starting immediately after the Cretaceous/Paleogene (K/Pg) boundary mass extinction (spanning from theGuembelitria cretaceaZone to the lower part of theP. pseudobulloidesZone). This contrasts with the proportionately low frequency of aberrant tests (generally <2%) identified within the uppermost Maastrichtian, suggesting more stable environmental conditions during the last ~50–100 Kyr of the Cretaceous. Two main pulses with abundant aberrant tests were recognized in the earliest Danian, the one recorded in the well-known K/Pg boundary clay being the more intense of those (maxima of >18%). These main pulses of aberrants coincide approximately with relevant quantitative and evolutionary turnovers in the planktic foraminiferal assemblages. In this paper, we explore the relation of these high values of the foraminiferal abnormality index with the environmental changes induced by the meteorite impact of Chicxulub in Yucatan, Mexico, and the massive eruptions of the Deccan Traps, India.

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