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Polyandry increases offspring viability and mother productivity but does not decrease mother survival in Drosophila pseudoobscura

Mating signals are often directed at numerous senses and provide information about species identity, gender, receptiveness, individual identity and mate quality. Given the diversity of colourful body...Full Text Available

2006-07-07

A Novel Function of the DNA Repair Gene rhp6 in Mating-Type Silencing by Chromatin Remodeling in Fission Yeast

Polyandrous mating is common, but the benefits for females of polyandry remain controversial. To test whether mating with multiple males affects female fitness, we compared lifetime components of fitness...Full Text Available

2010-08-03

Sperm competition risk affects male mate choice copying

Recent studies have indicated that the DNA replication machinery is coupled to silencing of mating-type loci in the budding yeast Saccharomyces cerevisiae, and a similar silencing mechanism...Full Text Available

1998-09-01

British Library Electronic Table of Contents (United Kingdom)

Mate choice copying was mostly described as a strategy employed by females to assess the quality of potential mates, but also males can copy other males? mate choice. An open question in this context is whether and how copying males evaluate sperm competition risk, as mating with a female that has already copulated with another male obviously sets the stage for intense sperm competition (i.e., in species with internal fertilization). Using the livebearing Atlantic molly (Poecilia mexicana) as a model, we asked (a) whether males of that species indeed copy other males? choices, and if they do so, (b) whether copying males strategically adjust their behavior to sperm competition risk. We used an approach where focal males could first choose to associate with a large or a small stimulus femal...

2011-01-01

Sex starved: do resource-limited males ensure fertilization success at the expense of precopulatory mating success?

British Library Electronic Table of Contents (United Kingdom)

Theory predicts trade-offs between investment in various life history traits, and it is also now generally accepted that reproduction is costly for males. Males must therefore optimize resource allocation across several episodes of reproduction, and this includes investment in both pre- and postcopulatory fitness components. We investigated this in the sperm-polymorphic Indian meal moth, Plodia interpunctella. Resource-limited males were smaller, and had decreased precopulatory mating success, measured as lifetime number of matings. However, they transferred similar numbers of fertile sperm as males reared under high-quality larval conditions, and more nonfertile sperm. By mating less frequently, resource-limited males may allocate sufficient resources to the matings they achieve to ensure...

2011-01-01

Effects of gamma irradiation on the sperm transmission and oviposition response in Helicoverpa armigera (L. NOCTUIDAE)

The biological aspects and behaviour of Heliothis virescens Fabricius adults from irradiated diapausal pupae

Transmissions of sperm by unirradiated and irradiated cotton bollworm, Helicoverpa armigera, were studied by live dissection of females immediately after the initiation of mating. In cotton bollworm the sperm transfer was rather a complex process. In fact unirradiated males failed to transfer sperm in about 19% of their matings. When irradiated with 250 Gy and 400 Gy, aberrations of sperm transmission were about 21% and 50% respectively. The failure of spermatophore 'cap' location was an important reason of sperm transmission aberrations. When females mated to high-dose-irradiated males, their oviposition response appeared abnormal

2002-02-01

The Effect of Experience on Male Courtship and Mating Behaviors in a Cellar Spider

... bollworm fertility gamma radiation genetic radiation effects life span mating

1974-07-22

NASA - Students' Robots to Take Place of Spacewalkers in NASA Pool

... video recorded in an isolated booth under a Panasonic WV-CP470 video camera located in an environmentally ... ...

NASA - JSC Hosts National Underwater Robotics Competition

Jun 21, 2006 ... The competition is organized by the Marine Advanced Technology Education Center (MATE) and Marine Technology Society's (MTS) ROV Committee. ...

Comparative mating and reproductive performance of radiation sterilized and radiation induced F_1 sterile males of Earias vittella (Fabricius)

Jun 8, 2005... competition June 17-19, organized by the Marine Advanced Technology Education (MATE) Center and the Marine Technology Society. ...

Discriminating Males and Unpredictable Females: Males Bias Sperm Allocation in Favor of Virgin Females

Studies were conducted on mating behaviour and reproductive performance of a) Earias vittella (F.) males rendered sterile by exposing them to 300 Gy gamma rays and b) F_1 sterile males obtained by exposing parent male to 100 Gy gamma rays. For the study, males were allowed only one mating with a normal female. Results revealed that premating period, period in copula and per cent insects mating were not adversely affected in case of both types of sterile males and fecundity also remained unaffected. However, in both types of sterile males, incidence of spermatophore transfer without sperm was very large and such an occurrence (including reduced spermatophore transfer) was significantly higher in case of radiation sterilized males compared to the F_1 sterile males. Inability to produce and transfer spermatophore and/or sperm appeared to be a major cause behind the reduced mating competitiveness of both ...

British Library Electronic Table of Contents (United Kingdom)

Abstract When both sexes mate with multiple partners, theory predicts that males should adjust their investment in ejaculates in response to the risk and/or intensity of sperm competition. Here, we demonstrate that, in the harlequin beetle riding pseudoscorpion, Cordylochernes scorpioides, males use cues deposited on females by previous males to distinguish between virgin, once-mated, and multiply-mated females and adjust sperm allocation accordingly. Sperm number declined in direct proportion to the number of previous males, with virgin females receiving nearly three times more sperm than females exposed to three previous males. Given the lack of first-male sperm precedence in C.scorpioides, this pattern is not consistent with current sperm competition models and appears best explained by...

2011-01-01

DNase-resistant transfer of chromosomal cat and tet insertions by filter mating in pneumococcus

The prairie vole: an emerging model organism for understanding the social brain

Genes for chloramphenicol resistance, Cm(r) and tetracycline resistance, Tc(r), which are present as heterologous insertions in the chromosomes of some clinical isolates of Streptococcus pneumoniae (pneumococcus) and derivative strains, were transferred at a low frequency to other pneumococci by a DNase-resistant filter mating process that resembles conjugation. Cotransfer of Cm(r) and Tc(r) was the most common event. Neither the donor strains nor the transconjugants contained detectable plasmids. Transconjugants acted as donors for transformation and for filter mating and had properties similar to those of the parent strain. The presence of the conjugative plasmid pIP501 in the donor did not appear to influence the transfer properties of the Cm(r) or Tc(r) determinants.

1980-01-01

Sperm competition games: optimal sperm allocation in response to the size of competing ejaculates

Unlike most mammalian species, the prairie vole is highly affiliative, forms enduring social bonds between mates, and displays biparental behavior. Over two decades of research in this species...Full Text Available

2010-02-01

Sexual conflict over mating and fertilization: an overview

Sperm competition theory predicts that when males are certain of sperm competition, they should decrease sperm investment in matings with an increasing number of competing ejaculates. How males should...Full Text Available

2007-01-22

Mitochondrial transmission during mating in Saccharomyces cerevisiae is determined by mitochondrial fusion and fission and the intramitochondrial segregation of mitochondrial DNA.

Sexual conflict is a conflict between the evolutionary interests of individuals of the two sexes. The sexes can have different trait optima but this need not imply conflict if their optima can be attained...Full Text Available

2006-02-28

Male-derived cuticular hydrocarbons signal sperm competition intensity and affect ejaculate expenditure in crickets

To gain insight into the process of mitochondrial transmission in yeast, we directly labeled mitochondrial proteins and mitochondrial DNA (mtDNA) and observed their fate after the fusion of two cells....Full Text Available

1997-07-01

Influence of major histocompatibility complex genotype on mating success in a free-ranging reptile population

Female sexual promiscuity can have significant effects on male mating decisions because it increases the intensity of competition between ejaculates for fertilization. Because sperm production is costly,...Full Text Available

2009-01-22

High Outcrossing in the Annual Colonizing Species Ambrosia artemisiifolia (Asteraceae)

Major histocompatibility complex (MHC) genes are highly polymorphic components of the vertebrate immune system, which play a key role in pathogen resistance. MHC genes may also function as odour-related...Full Text Available

2009-05-07

1 2 3 4

Female Scent Signals Enhance the Resistance of Male Mice to Influenza

Background and AimsVariation in mating patterns may be particularly evident in colonizing species because they commonly experience wide variation in plant density. Here, the role...Full Text Available

2008-06-01

Dorsal cortex volume in male side-blotched lizards (Uta stansburiana) is associated with different space use strategies

BackgroundThe scent from receptive female mice functions as a signal, which stimulates male mice to search for potential mating partners. This searching behavior is coupled with...Full Text Available

Affinity maturation of human botulinum neurotoxin antibodies by light chain shuffling via yeast mating

Spatial abilities have been associated with many ecologically-relevant behaviors such as territoriality, mate choice, navigation and acquisition of food resources. Differential demands on spatial...Full Text Available

2009-07-01

A Novel Form of Transcriptional Silencing by Sum1-1 Requires Hst1 and the Origin Recognition Complex

Botulism is caused by the botulinum neurotoxins (BoNTs), the most poisonous substance known. Because of the high potency of BoNT, development of diagnostic and therapeutic antibodies for botulism requires...Full Text Available

2010-04-01

The monogamous reproductive strategy in Lepidoptera

In the yeast Saccharomyces cerevisiae, a and α mating-type information is stored in transcriptionally silenced cassettes called HML and HMR....Full Text Available

2001-05-01

British Library Electronic Table of Contents (United Kingdom)

On the basis of literary sources and experimental data, the advantages of a monogamous reproductive strategy are analyzed. Monogamous species of Lepidoptera have no postcopulative mechanisms of control over the success of reproductive sperm competition, cryptic female choice, and, probably, the male?s nuptial gift. Selection of the sex partner and of the quality of the future generation is determined by the precopulative and copulative mechanisms of the reproductive behavior, which include chemocommunication and a ?lock-and-key? mechanism. In an experiment with one male and one female, the quota of successful mating can depend on the morphological complication of the genital apparatus of males. Cases are considered of repeated mating for some, usually monogamous, species. In comparison wit...

2011-01-01

Combined release of radiation sterilized adults of spotted bollworm, Earias vittella (Fabricius)

Inherited sterility induced in progeny of gamma irradiated males and females spiny bollworm, Earias Insulana boisd ,effect on fecundity, fertility and mating

Feasibility of using combined release of sterile males and sterile females for population suppression of Earias vittella (Fabricius) was evaluated on okra in two ways. In one study, a combined release of sterile males and sterile females was evaluated under simulated conditions in laboratory, a 10: 10: 1: 1 (sterile male: sterile female: normal female: normal male) ratio effected > 99% sterility. In the second study, in a field cage experiment, a combined release of sterile males and sterile females was evaluated using normal males and tethered normal females. In this experiment, the release of sterile males and sterile females in 10: 10: 1: 1 ratio caused complete 'shut off' of mating of normal females for first 2 days and indicated>93% reduction in the larval progeny in the next generation. The tethered females were allowed to mate only once. E. vittella females mate multiply and so with overwhelming numbers of ...

2005-06-01

Phenotypic plasticity in sex allocation for a simultaneously hermaphroditic coral reef fish

adult males and females, less than 24 hours old, of the spiny bollworm, Earias Insulana boisd. were irradiated with sub sterilizing doses of 50,80,100 and 150 gray (Gy). treated moths were out crossed with normal adults and observed for their ability to reproduce. inherited deleterious effects resulting from irradiation of p_1 moths were recorded for several generations. the reduction in both fecundity and egg viability increased by increasing the dose applied to p_1 adult moths .at all tested doses, the females were more radiosensitive than males, as for reduction in fecundity and egg viability. the progeny from irradiated parental females are not as sterile as the progeny from irradiated parental males. the reduction of egg hatching continued in the progeny of irradiated males through F_1 and to lesser extent through F_2 .on the other hand , irradiation of P_1 females reduced the rate of egg hatching among parental generation and to lesser extent among the first filial generation . ...

2004-02-01

British Library Electronic Table of Contents (United Kingdom)

Phenotypic plasticity can facilitate reproductive strategies that maximize mating success in variable environments and lead to differences in sex allocation among populations. For simultaneous hermaphrodites with sperm competition, including Serranus tortugarum a small coral reef fish, proportional male allocation (testis in total gonad) is often greater where local density or mating group size is higher. We tested whether S. tortugarum reduced male allocation when transplanted from a higher density site to a lower density site. After 4?months, transplants mirrored the sex-allocation patterns of the resident population on their new reef. Transplants had significantly lower male allocation than representatives from their source population, largely as a result of reduced testis mass relative...

2011-01-01

Mobilization of the genetically engineered plasmid pHSV106 from Escherichia coli HB101(pHSV106) to Enterobacter cloacae in drinking water.

GM mosquito wild release takes campaigners by surprise - SciDev.Net

We have used triparental matings to demonstrate transfer (mobilization) of the nonconjugative genetically engineered plasmid pHSV106, which contains the thymidine kinase gene of herpes simplex virus...Full Text Available

1991-01-01

Wastenet

... The male GM mosquitoes mate with normal females to produce larvae that die unless the antibiotic tetracycline is present. In tetracycline's absence an enzyme accumulates to a toxic level, killing the larvae. The developers hope the strategy could be combined with other mosquito control methods to reduce transmission in dengue-prone areas. Ricarda Steinbrecher, a geneticist and co-director of EcoNexus -a UK-based non-profit research organisation -expressed surprise ...

GM Mosquito Wild Release Takes Campaigners by Surprise

Wastenet

Effect of mating surface on the high temperature wear of 253 MA alloy

Amazon.com: Customer Reviews: The Five Love Languages: How to Express Heartfelt Commitment to Your Mate

The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. The morphology of the worn surfaces and the transverse section of the worn surfaces are examined under scanning electron ...

2004-04-01

Wastenet

... I don't think the 5 categories are exclusive nor do they represent the universe of ways people best receive love and affection. The author addresses this last point somewhat by saying there are many dialects within the 5 languages. Some might view that as a cop out. My strongest complaint is that the language of the book is dumb downed to reach the lowest grade of reader. Like ...

Program NetMoment; Simultaneous Calculation of Moment, Source Corner Frequency, and Site Specific t* from Network Recordings

Mutations in cyr1 and pat1 reveal pheromone-induced G1 arrest in the fission yeast Schizosaccharomyces pombe

The purpose of computer program NetMoment (Appendix I) is to utilize fundamental knowledge of earthquake sources, propagation attenuation, and site response in a simultaneous inversion of network data to determine the moment and source corner frequency of earthquakes, and site specific t*. The source parameters are especially difficult to determine for small earthquakes. A fundamental problem in determining the source corner frequencies of small earthquakes is that site response can result in spectral corner frequencies in the range that may be expected from the earthquakes themselves. Several authors have identified this as fmax (Hanks, 1982), a constant corner frequency for small events so that below threshold moment (about 1.0 x 10{sup 21} dyne-cm) the corner frequency remains constant the size of events diminishes. Hutchings and Wu (1990) found that for the southern California region, events with moment less than about 1.5 x 10{sup 21} dyne-cm (about magnitude 3.4) show no source ...

2001-12-12

DEFF Research Database (Denmark)

Investigations into sexual differentiation and pheromone response in the fission yeast Schizosaccharomyces pombe are complicated by the need to first starve the cells of nitrogen. Most mating-related experiments are therefore performed on non-dividing cells. Here we overcome this problem by using two mutants that bypass the nutritional requirements and respond to the M-factor mating pheromone in rich medium. The first mutant lacks the cyr1 gene which encodes adenylate cyclase and these cells contain no measurable amounts of cAMP. When M-factor is added to a growing h+ cyr1- strain it causes a transient G1 arrest of cell division, transcription of mat1-Pm, and elongation of the cells to form shmoos. The second mutant contains the temperature-sensitive pat1-114 allele. At 30 degrees C this mutant was previously shown not only to bypass the nutritional signal but also to stop growing in a state derepressed for pheromone-controlled functions. We ...

1994-01-01

Behavioral interactions increase pregnancy blocking by unfamiliar male meadow voles.

Loaded Transducer Fpr Downhole Drilling Component

Unfamiliar male meadow voles induce pregnancy disruptions when they are in physical contact with females, but the presence of the female's original mate partially protects her from the blocking effects of an unfamiliar male. This research examines how behavioral interactions affect pregnancy disruptions by testing two hypotheses: a) original males protect females by reducing the aggressive interactions between females and strange males; and b) administration of clonidine, an alpha 2-adrenergic receptor agonist that decreases activity, aggression, and sexual motivation, will decrease the pregnancy-blocking ability of strange males. Strange males were more aggressive when the original sire was absent, indicating that this change in behavior may be related to their greater success in disrupting pregnancy. When injected with clonidine, males were less likely to block pregnancy, and they showed less contact and mating behavior than when they ...

1996-10-01

Fiber optic feedthrough module and method of making same

A robust transmission element for transmitting information between downhole tools, such as sections of drill pipe, in the presence of hostile environmental conditions, such as heat, dirt, rocks, mud, fluids, lubricants, and the like. The transmission element maintains reliable connectivity between transmission elements, thereby providing an uninterrupted flow of information between drill string components. A transmission element is mounted within a recess proximate a mating surface of a downhole drilling component, such as a section of drill pipe. To close gaps present between transmission elements, transmission elements may be biased with a "spring force," urging them closer together.

2005-07-05

Evaluation of efficacy of radiation-sterilized females for population suppression of Earias vittella (Fabricius)

A fiber optic feedthrough module which comprises a metal sleeve, a fiber optic element extending through the sleeve in spaced relation thereto, and a tandem series of centrally-apertured mating annular sealant bodies of thermoplastic material surrounding the fiber optic element and compressed between it and the sleeve. The module is made by first providing a loose subassembly of a plurality of individual but interfitting sealant bodies on the fiber optic element and then inserting this subassembly into a metal sleeve, following by swaging the whole assembly which eliminates clearances and provides sealed interfaces between the various contacting components. (author).

1983-05-25

A high stopping power, large acceptance Bragg curve spectrometer for heavy ion detection

Feasibility of using sterile females for population suppression of Earias vittella (Fabricius) was evaluated by conducting studies on mating competitiveness of radiation sterilized females, both in individual pairs and in simulated large population conditions. Results showed that sterility induced by using a 10:1:1 ratio (sterile female: normal female: normal male) in single pair experiments and also in simulated large population conditions was more than 99.0 per cent. Release of radiation- sterilized females of E. vittella in natural populations has thus an excellent potential for population suppression. (author)

1 2 3 4

A high stopping power, large acceptance Bragg curve spectrometer for heavy ion detection

A large acceptance, high stopping power Bragg curve spectrometer has been developed for use in coincidence experiments with heavy ions. The electron collection fields are radial and position information is obtained from a resistive anode. The detector is 60 cm deep and operates at pressures of up to 2.5 atm of P-10 gas. It is mated to a scattering chamber which allows it to be moved out of plane during coincidence measurements. Factors affecting the performance of the detector are discussed, and results obtained with the detector are presented. (orig.).

1991-05-01

Studies on inherited sterility induced in the progeny of gamma irradiated cotton leaf worm, Spodoptera littorals (Boisd.)

Inherited sterility progeny gamma irradiated male Spiny Bollworm Earias Insulana Boisd

Full - grown pupae of the cotton leaf worm Spodoptera littorals (Boisd.) were gamma - irradiated with low doses of 25,50,75, or 100 Gy for male line and with 50 or 100 Gy for female line . The effects on reproduction, development and sex ratio were the biological aspects studied among P1,F1,F2 and F 3 generations . Also, the effects of dose accumulation applied grown male pupae through two or three filial generations and the retarded influence on their F1,F2,and F 3 progeny were examined. In another trial the histological examinations for ovaries and testes of irradiated parents and for their generation were made . The F1 males were more sterile than irradiated parental males while F1 females were more fertile than their irradiated parental females. Irradiation of P1 males did not clearly affect neither the percentage of mated females nor the average number of spermatophores per mated female among the individuals of P1,F1,F2 and F 3 ...

Variation in male reproductive traits among three bitterling fishes (Acheilognathinae: Cyprinidae) in relation to the mating system

The present work studies the fecundity, egg batching and mating of normal females of Earias Insulana Boisd. crossed with males irradiated as 24 h adult moths with two doses (80 and 100 Gy.) of gamma radiation. The male progeny were out bred or inbred with untreated individuals for two successive generations F_1and F_2 and their progeny was observed for any inherited deleterious effects on reproduction. The female fecundity and egg hatch were significantly reduced among P1,F1 and F2 generations by increasing the dosages applied to P_1 males as compared with the untreated control. The percentage of mating of P_1 females was significantly reduced at the two doses as compared to the untreated control. The average number of spermatophores per mated female was reduced among P_1,F_1 and F_2 generations when parental males were irradiated with 100 Gy. The larval and pupal mortality a,o mg F_1, F_2 and F_3 generations was high and ...

2003-01-01

British Library Electronic Table of Contents (United Kingdom)

Male traits that correlate with fertilization success include testis size and structure, ejaculate size, ejaculation frequency, and sperm motility. Two hypotheses potentially explain interspecific differences in these traits: sperm competition and sperm limitation. We examined variation in six traits associated with fertilization success in three closely-related species of bitterling fish; the European bitterling (Rhodeus amarus), the Chinese rose bitterling (Rhodeus ocellatus), and the Chinese bitterling (Rhodeus sinensis). Interspecific differences indicated that the three study species have evolved different sperm allocation strategies. Rhodeus amarus displayed the most developed reproductive apparatus with a number of traits associated with both high levels of sperm production and fert...

2011-01-01

Tree fruit IPM programs in the western United States: the challenge of enhancing biological control through intensive management

British Library Electronic Table of Contents (United Kingdom)

The seminal work of Stern and his coauthors on integrated control has had a profound and long-lasting effect on the development of IPM programs in western orchard systems. Management systems based solely on pesticides have proven to be unstable, and the success of IPM systems in western orchards has been driven by conservation of natural enemies to control secondary pests, combined with pesticides and mating disruption to suppress the key lepidopteran pests. However, the legislatively mandated changes in pesticide use patterns prompted by the Food Quality Protection Act of 1996 have resulted in an increased instability of pest populations in orchards because of natural enemy destruction. The management system changes have made it necessary to focus efforts on enhancing biological control n...

2009-01-01

Space power systems prelaunch integration

Reproductive toxicologic evaluations of Bulbine natalensis Baker stem extract in albino rats

The sequence of events from the assembly of a space nuclear power system to its integration in the Space Shuttle Transportation System (STS) is considered. First, the sequence followed for SNAP-10A, the only free world space reactor electric power system ever launched and operated in space, is reviewed. Before shipment, the SNAP-10A reactor was raised to operating temperature using electrically supplied heat and operated at low power for control calibration. Next we discuss shipment to the launch site, a phase that is critical because of the potential for various accidents. Once the power system arrives at the launch site, the processing sequence is performed. This sequence includes checkout, mating with the payload or upper stage launch vehicle, and integration into the STS.

British Library Electronic Table of Contents (United Kingdom)

The effects of oral administration of aqueous extract of Bulbine natalensis Baker stem at daily doses of 25, 50, and 100mg/kg body weight on the reproductive function of Wistar rats were evaluated. The indices of mating and fertility success as well as quantal frequency increased after 7 days of treatment in all the dose groups except the 100mg/kg body weight group. The number of litters was not statistically different (P>0.05) from the control. Whereas the absolute weights of the epididymis, seminal vesicle, and prostate were not affected, that of the testes was significantly increased. The epididymal sperm count, motility, morphology, and viscosity were not different from the control after 7 days of treatment. The male rat serum testosterone, progesterone, luteinizing hormone, and follic...

2009-01-01

Molecular evidence for variation in polyandry among praying mantids (Mantodea: Ciulfina)

British Library Electronic Table of Contents (United Kingdom)

Abstract Estimating paternity patterns provides insights into the importance of competing evolutionary forces on mating systems. The number of sires contributing to a female's offspring is mostly influenced by her relative promiscuity. However, in a postcopulatory context, it will also be affected by sperm competition and cryptic female choice. Here, we describe the paternity patterns of two species of praying mantis from the genus Ciulfina, the agile praying mantid. This study is the first to describe patterns of paternity in the Mantodea. We found a variation in paternity in these two closely related species. Ciulfina rentzi exhibited single paternity, with a single male siring all offspring within a clutch. By contrast, Ciulfina klassi displayed multiple paternity, with the minimum numb...

2011-01-01

Longer exaggerated male genitalia confer defensive sperm-competitive benefits in an earwig

British Library Electronic Table of Contents (United Kingdom)

As evidence mounts that male genitalia can affect relative fertilisation success, the role that sexual selection has played in the rapid and divergent evolution of genitalia is becoming increasingly recognized. Unfortunately, the limited functional understanding of these complex structures and their interactions with the female reproductive tract often limit interpretation regarding their evolution. Here, we address this issue using the earwig Euborellia brunneri, where both the male intromittent organ and the female spermatheca are highly exaggerated in length yet structurally simple. In a double mating design, we use the sterile male technique to study how sperm precedence patterns are affected by male genital length, male age, and the size of the male sperm storage organ, the seminal ve...

2011-01-01

Influence of SiC addition on tribological properties of SiAlON

British Library Electronic Table of Contents (United Kingdom)

The tribological properties of gas pressure sintered SiAlON and its composite with 18wt% silicon carbide (SiC) against two different mating materials, i.e., alumina and SiAlON are evaluated. SiAlON and SiAlON-18%SiC composite ceramics were prepared by pressure less sintering and gas pressure sintering. Fretting wear tests were carried out under dry unlubricated ambient conditions (room temperature 23-25^oC; relative humidity 50-55%) with a load of 8N for 45,000 cycles. Friction and wear properties of SiAlON-SiC proved better than the monolithic SiAlON. The formation of silica roll like structure on the composite worn surface was observed.

2011-01-01

Flight songs of Dusky Flycatchers: a response to bird-hunting raptors?

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT. Flight-song displays usually include distinctive vocalizations and behaviors that are probably energetically expensive and also likely to attract the attention of aerial predators. We observed flight songs performed by Dusky Flycatchers (Empidonax oberholseri) in two breeding populations. During 15 yr at Tioga Pass, California, we observed the display twice and, during 9 yr at Steamboat Mountain, British Columbia, we observed 21 flight-song displays. These displays were generally observed later in the breeding season, suggesting that they were not used for courtship, mate attraction, or territory defense. However, for 83% of these displays, a raptor was observed to be present, usually either an American Kestrel (Falco sparverius) or a Sharp-shinned Hawk (Accipiter striatus). We h...

2010-01-01

Experimental study on Satureja montana as a treatment for premature ejaculation

British Library Electronic Table of Contents (United Kingdom)

Aim of the study: Satureja montana (winter savory) is a medicinal plant traditionally used to treat different disorders including male sexual dysfunction. In this study we evaluated the effect of Satureja montana hydroalcoholic extract on copulatory behavior of sexually potent male rats. Materials and methods: The extract was orally administered acutely or repetitively for 8 consecutive days at the doses of 25 and 50mg/kg. The main parameters of sexual behavior, mount (ML), intromission (IL), ejaculation (EL) latencies and post-ejaculatory interval (PEI), were evaluated in animals submitted to mating test and multiple ejaculations test. Testosterone serum levels were measured in rats acutely treated with Satureja montana extract dosed at 50mg/kg. In addition the open field test was conduct...

2011-01-01

A large solid angle, high stopping power Bragg curve spectrometer for coincidence measurements

A large solid angle, high stopping power Bragg curve spectrometer for coincidence measurements

A large acceptance, high stopping power, Bragg curve spectrometer has been developed for use in coincidence experiments with heavy ions. The electron collection fields are radial and position information is obtained from a resistive anode. The detector is 60 cm deep and operates at pressures of up to 2.5 atm of P-10 gas. It is mated to a scattering chamber which allows it to be moved out of plane during coincidence measurements. The detector design was aided by the results of computer simulations of the electron collection process in the detector, and of the signal processing in the electronics. The signals from the Bragg curve spectrometer are recorded in a waveform digitizer and the Bragg peak height, range, position and pileup rejection information are determined from software analysis of the recorded signals. Factors limiting the performance of the detector are discussed, and results obtained with the detector are presented. (orig.).

1991-09-01

Inherited Sterility in Progeny of Gamma-Irradiated Spiny Bollworm, Earias Insulana Boisd

The Simultaneous effect of gamma radiation on susceptibility of the cotton leaf worm Spodoptera Littoralis (Boisd.) to methomy

The inherited sterility of the spiny bollworm Earias Insulana Boisd. Irradiated as parental male adults, with sub sterilizing doses of 100-200 Gy has been studied throughout three successive generations. In general, the female fecundity decreased at the three doses of irradiations (100, 150 and 200 Gy) throughout P_1. F_1, F_2 and F_3 generations as compared to control. The reduction was insignificant in all treatments with some exceptions at 200 Gy, in the parental generation and 150 and 200 Gy bin F_2 generation. Egg hatch of the parental generation was obviously reduced at 100, 150 and 200 Gy treatments as compared to the control. The progeny of F_1 males were evidently more sterile than their irradiated male parents. The effect continued in the F_2, population, however F_3 males almost regained their fertility. Irradiation of P_1 males did not greatly affect mating ability among P_1, F_1, F_2 and F_3 generations. The reduction in mating ...

1999-01-01

Review of the study and application on nuclear forensic analysis

The simultaneous effects of irradiating full grown pupae of Spodoptera Littoralis with doses 30 and 40 krad followed by topical treatment of adults with methomyl were studied. Gamma rays decreased the toxicity of methomyl against adult moths. The obtained LD_5_0 values for male moths emerging from unirradiated or irradiated pupae with 30 or 40 krad were 7, 9.93 and 10.33 u g/g. b.wt., respectively. F1 larvae (produced from unirradiated females mated to irradiated males) became more tolerant to methomyl by increasing radiation doses from 5 to 30 krad. The toxicity of methomyl to F1, F2 and F3 larvae (whose male parents had been irradiated in the pupal stage with 10 krad) was less than its toxicity to the larvae produced from unirradiated parents. F2 and F3 larvae were more tolerant to methomyl effect than the F1 larvae.

Male mammals respond to a risk of sperm competition conveyed by odours of conspecific males

For the interests of national security, many scientists who work in the field of nuclear forensic analysis have carried out extensive work in the past on the detection of radioactive material and attributions study, developed a series of scientific and technical means to trace and detect illicit circulation of nuclear materials used to weapons and other radioactive materials which impair public security. All these questions relate to physical, chemical, biological attribution of materials. The nuclear forensic analysis has already become a special, up-to-date sphere of learning. The goal of the study of nuclear forensics is to prevent terrorists from acquiring not only nuclear weapons but also mate- rials that can be used to make such weapons, including radioactive materials for nuclear power plants, and medical radioisotope to and provide us as many clues of environmental links as possible that could help us trace the smuggling path, to answer the following ...

2009-12-01

Characterization of the heterokaryotic and vegetative diploid phases of Magnaporthe grisea

Sperm competition occurs when a female copulates with two or more males and the sperm of those males compete within the female's reproductive tract to fertilize her eggs. The frequent occurrence of sperm competition has forced males of many species to develop different strategies to overcome the sperm of competing males. A prevalent strategy is for males to increase their sperm investment (total number of sperm allocated by a male to a particular female) after detecting a risk of sperm competition. It has been shown that the proportion of sperm that one male contributes to the sperm pool of a female is correlated with the proportion of offspring sired by that male. Therefore, by increasing his sperm investment a male may bias a potential sperm competition in his favour. Here we show that male meadow voles, Microtus pennsylvanicus, increase their sperm investment when they mate in the presence of another male's odours. Such an increase in sperm investment does not ...

2004-09-01

An efficient hybrid evolutionary algorithm based on PSO and HBMO algorithms for multi-objective Distribution Feeder Reconfiguration

The heterokaryotic and vegetative diploid phases of Magnaporthe grisea, a fungal pathogen of grasses, have been characterized. Hyphal tip cells and conidia (vegetative spores) taken from these heterokaryons are auxotrophs with phenotypes identical to one or the other of the parents. M. grisea heterokaryons have completely septate hyphae with a single nucleus per cell. Heterokaryons have been utilized for complementation and dominance testing of mutations that affect nutritional characteristics of the fungus. Heterokaryons growing on minimal medium spontaneously give rise to fast-growing sectors that have the genetic properties expected of unstable heterozygous diploids. In fast-growing sectors, most hyphal tip cells are unstable prototrophs. The conidia collected from fast-growing sectors include stable and unstable prototrophs, as well as auxotrophs that exhibit a wide range of phenotypes, including many recombinant classes. Genetic linkage in meiosis has been detected between two ...

1984-01-01

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Wear and friction behaviour of duplex-treated AISI 4140 steel

This paper introduces a robust searching hybrid evolutionary algorithm to solve the multi-objective Distribution Feeder Reconfiguration (DFR). The main objective of the DFR is to minimize the real power loss, deviation of the nodes' voltage, the number of switching operations, and balance the loads on the feeders. Because of the fact that the objectives are different and no commensurable, it is difficult to solve the problem by conventional approaches that may optimize a single objective. This paper presents a new approach based on norm3 for the DFR problem. In the proposed method, the objective functions are considered as a vector and the aim is to maximize the distance (norm2) between the objective function vector and the worst objective function vector while the constraints are met. Since the proposed DFR is a multi objective and non-differentiable optimization problem, a new hybrid evolutionary algorithm (EA) based on the combination of the Honey Bee Mating ...

2009-08-01

Tribological properties of plasma and pulse plasma nitrided AISI 4140 steel

In this study samples of AISI 4140 steel were pretreated by plasma nitriding and coated with two different physical vapour deposited coatings (TiN and TiAlN). A hardened AISI 4140 sample and a coated sample were also included in the investigation. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, two different nitriding conditions - a conventional 25% N{sub 2} and an N{sub 2}-poor gas mixture - were used. The specimens were investigated with respect to their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests in which the duplex-treated pins were mated to hardened ball bearing steel discs were performed in a pin-on-disc machine under dry sliding conditions. Metallography, scanning electron microscopy and profilometry were used to analyse the worn surfaces in order to determine the dominant friction and wear characteristics of the samples investigated. The results show ...

1999-11-01

Social environment and steroid hormones affect species and sex differences in immune function among voles.

Plasma nitriding is usually used for ferrous materials to improve their surface properties. Knowledge of the properties of thin surface layers is essential for designing engineering components with optimal wear performance. In our study, we investigated the microstructural, mechanical and tribological properties of plasma- and pulse plasma-nitrided AISI 4140 steel in comparison to hardened steel. The influence of nitriding case depth as well as the presence of a compound layer on its tribological behaviour was also examined. Plasma and pulse plasma nitriding were carried out using commercial nitriding processes. Nitrided samples were fully characterised, using metallographic, SEM microscopic, microhardness and profilometric techniques, before and after wear testing. Wear tests were performed on a pin-on-disc wear testing machine in which nitrided pins were mated to hardened ball bearing steel discs. The wear tests were carried out under dry conditions where ...

1998-10-10

Prolactin and testosterone affect seasonal differences in male meadow vole, microtus pennsylvanicus, odor preferences for female conspecifics.

Testosterone has bipotential effects on male fitness; that is, it both suppresses immune function and maintains characteristics important for reproductive success. Presumably, these effects of testosterone may be more pronounced among polygynous species because testosterone concentrations are generally higher among polygynous than monogamous males. The present study examined sex and species differences in cell-mediated immunity among four arvicoline rodents. The role of mating system and sex steroids in sex differences in immune function was examined in individually housed polygynous meadow (Microtus pennsylvanicus) and montane (M. montanus) voles and monogamous prairie (M. ochrogaster) and pine (M. pinetorum) voles in Experiment 1. No sex differences in splenocyte proliferation were observed among the four species and circulating testosterone concentrations did not correlate with immune function of individuals within each species. The contribution of social ...

1997-08-01

Meadow voles, Microtus pennsylvanicus, have the capacity to recall the "what", "where", and "when" of a single past event.

Studies on nonseasonally breeding males have demonstrated that high titers of testosterone (T) stimulate reproduction, whereas high titers of prolactin (PRL) inhibit it. Recent evidence, however, suggests that for seasonally breeding males high titers of both PRL and T stimulate behaviors that support reproduction and mating. Thus, we hypothesized that high titers of both PRL and T are necessary and sufficient for male meadow voles to show a preference for the odor of long-photoperiod (LP) females. We tested this hypothesis by treating castrated LP males with bromocriptine and/or T, and by treating castrated short-photoperiod (SP) males with PRL and/or T. The data showed that high titers of both PRL and T are necessary for LP male meadow voles to maintain a preference for the odor of LP female meadow voles, but high titers of both hormones are not sufficient to induce SP males to show such a preference. Only SP males with high T and low PRL titers showed ...

Investigation of genomic instability by assay of DNA fingerprint from the offspring of male mice exposed to chronic low-level #gamma#-radiation

Some non-human animals may possess the ability to recall the "what", "where", and "when" of a single past event. We tested the hypothesis that male meadow voles possess the capacity to recall the "what", "where", and "when" of a single past event associated with mate selection in two experiments. Briefly, male voles were allowed to explore an apparatus that contained two chambers. One chamber contained a day-20 pregnant female (24 h prepartum). The other chamber contained a sexually mature female that was neither pregnant nor lactating (REF female). Twenty-four hour after the exposure, the males were placed in the same apparatus, which was empty and clean. At this time, the pregnant female would have entered postpartum estrus (PPE), a period of heightened sexual receptivity. Males initially chose and spent significantly more time investigating the chamber that originally housed the pregnant female (now a PPE female) than the chamber that originally housed the REF ...

2007-07-26

Differential effects of chronic ingestion of tritiated water on prenatal brain development

By polymerase chain reaction with arbitrary primer (AP-PCR), the possibility of transmission of genome instability to somatic cells of the offspring (F_1 generation) from male parents of mice exposed to chronic low-dose #gamma#-radiation was studied. Male mice 15 days after exposure to 10-50 cGy were mated with unirradiated females. Biopsies were taken from tale tips of two month-old mice progeny for DNA separation. Primer in the AP-PCR was 20-mer oligonucleotide flanking the micro-satellite locus Atplb2 on chromosome 11 of the mouse. Comparative analysis of individual fingerprints of AP-PCR products on DNA-templates from the offspring of irradiated and unirradiated male mice revealed an increased variability of micro-satellite-associated sequences in the genome of the offspring of males exposed to 25 and 50 cGy. DNA-fingerprints of the offspring of male mice exposed to chronic irradiation doses 10 and 25 cGy. 15 days before fertilization (at the post-meiotic stage ...

2000-11-20

Design and performance of radioisotope space power systems based on OSC multitube AMTEC converter designs

Female rats were given tritiated drinking water (3 microCi/ml) from 30 days before mating up to and throughout pregnancy. At this low dose, the course and the outcome of pregnancy were normal. The differences between newborn body and cerebral weights of the treated rats and those of control animals were on the borderline of significance. In contrast, cerebral DNA and cerebral protein were highly significantly lower. In 30-35% of the treated population the DNA and protein values were more than 2 standard deviations (SD) below the mean values for the control population. Thus the number of the progeny of the mothers exposed to tritiated water that were considered to have outstandingly low levels of DNA and protein was 14-17 times greater than in the control group. The irradiated population also had 3-5% of severely affected individuals with cerebral DNA and protein values more than 2 SD below the mean of the experimental population. However, even in this irradiated ...

Cytogenetic effects of protracted gamma exposures from conception of male mice

This paper extends the analytical procedure described in another paper in these proceedings to analyze a variety of compact and light-weight OSC-designed radioisotope-heated generators. Those generators employed General Purpose Heat Source (GPHS) modules and a converter containing sixteen AMTEC cells of OSC`s revised five-tube design with enhanced cell wall reflectivity described in a companion paper in these proceedings. OSC found that the performance of the generator is primarily a function of the thermal insulation between the outside of the generator`s 16 cells and the inside of its wall. After examining a variety of insulation options, it was found that the generator`s performance is optimized by employing a hybrid insulation system, in which the space between the cells is filled with fibrous Min-K insulation, and the generator walls are lined with tapered (i.e., graded-length) multifoil insulation. The OSC design results in a very compact generator, with eight AMTEC cells on each ...

1997-12-31

Best of the lot : engineered measurement-while-drilling tool improves efficiency of operations

In order to gain an overall picture of the genetic effects of an increased level of background radiation it is necessary to study the results of protracted exposures to embryonic and immature germ-cell stages as well as to stages found in the mature organism. For this purpose, litters produced by female mice, kept in a 10 or 20 rad/day /sup 60/Co ..gamma..-irradiation field, were kept in the same fields from conception until about 60 days later, having absorbed doses of 526 and 1078 rad respectively. Tests on exposed female offspring showed them to be sterile. Eight weeks after removal from the gamma field, mean testis masses of males in the 20 rad/day series were only half normal but those receiving 10 rad/day were little affected. Frequencies of translocations in spermatocytes at diakinesis/metaphase I were only slightly increased in the exposed series, differences not being significant. Estimated rates of translocation induction were around 5 x 10sup(-6) per rad, about one-third of ...

1982-01-01

Analysis of advanced direct-injection diesel engine development strategies. Final report, 1 July 1995--9 July 1998

NuEra Oilfield Services Inc. combines various technologies, including advanced bearing assemblies and compact wireless decoders that interface with downhole directional tools, to engineer unique, purpose-built measurement-while-drilling (MWD) tool string packages. The 9-metre-long MWD tool string is lowered into the drill pipe from the surface. The directional module monitors the position of the drill bit, which the driller can monitor using an electronic drilling recorder at the surface. The directional drillstring uses a mud motor with adjustable bent housing to correct the direction of the well, as the system cannot steer while drilling. At bottomhole, mud circulation continues after the rotation of the drillstring has been stopped, driving the mud motor, which in turn drives the drill bit, permitting a new direction to be taken even though the drillstring is not turning. The operator points the bent housing in a new direction and slides the bit along before restarting the rotation ...

2010-10-15

Integrated systems for control of pink bollworm in cotton

The methodology of achieving a high power density (HPD, or brake mean effective pressure) direct-injection Diesel engine has been studied, which is directed to using high fuel/air ratio, high-speed and ceramic engine components. Among the main thrust to achieve these engine changes for an advanced Diesel engine is the design of a high injection pressure (HIP) fuel system. During the course of the present study, two Cummins 903 engines mated with a Rutger-built HIP were employed to investigate the engine response to HIP and in-cylinder processes by using the Rutgers high-speed infrared (IR) spectral digital imaging system. Five separate technical publications were prepared to report results obtained from the study. The main findings include: The HIP system permits engine operation at an air/fuel ratio of as rich as 18 to 1 with smoke emission not worse than with the conventional mechanical (low pressure) injection system; A high injection pressure improves HPD of a ...

1998-08-01

Investigation of Al{sub 2}O{sub 3}- and SSiC-ceramic under lubricated, reciprocating sliding contact and cavitation erosion

Full text: Pink bollworm (PBW), Pectinophora gossypiella (Saunders), an introduced pest from Mexico, first occurred in United States cotton production in Texas in 1917. Unacceptable economic losses have occurred. The development of PBW sterile moth release technology, gossyplure sex pheromone behavioral control, cotton plant cultural control to reduce overwintered PBW populations, and the transfer of the insect toxin protein gene into cotton from Bacillus thuringiensis kurstaki (Berliner) have provided an effective integrated pest management (IPM) system with PBW eradication potential. Sterile insect release was considered a potential option for PBW population suppression in the early 1960s. Research on the isolated island of St. Croix, (US Virgin Islands) demonstrated its validity. Reductions of larval infestations in bolls following sterile moth releases began when ratios of released PBW sterile male to native male moths averaged 70:1 in gossyplurebaited traps. Numbers of larvae per ...

2005-05-09

Development and evaluation of a conditionally lethal transgenic pink bollworm

Tribological performance of alumina and silicon carbide ceramics as well as of the hardened steel 100Cr6 for reference was studied during reciprocating sliding and cavitation erosion in isooctane as substitute of gasoline and in distilled water. It was the aim to characterize effects of surface finish of the specimens and the liquid media on friction, resistance to sliding wear and cavitation erosion. Sliding wear tests were run on the self-mated ceramics and ceramic/steel pairs under conditions of boundary lubrication using a laboratory tribometer with cylinder-on-plate geometry. Vibratory cavitation erosion tests were conducted according to ASTM G 32-92. High initial surface roughness of coarse ground specimens led to a distinct running-in period during sliding contact with a transition from high to low values of friction coefficient and wear intensity. Incubation time was reduced with increasing surface roughness in the cavitation tests. Depending on the ...

2005-03-01