2,796 research outputs found
Presencia de Cobitis maroccana Pellegrin, 1929 (Osteichthyes, Cobitidae) en el río Nalón (Cuenca del norte de España)
Comparing pre- and post-copulatory mate competition using social network analysis in wild crickets
This is the final version of the article. Available from the publisher via the DOI in this record.Data accessibility: Data are available through Open Research Exeter,
http://hdl.handle.net/10871/19103Sexual selection results from variation in success at multiple stages in the mating process, including competition before and after mating. The relationship between these forms of competition, such as whether they trade-off or reinforce one another, influences the role of sexual selection in evolution. However, the relationship between these 2 forms of competition is rarely quantified in the wild. We used video cameras to observe competition among male field crickets and their matings in the wild. We characterized pre- and post-copulatory competition as 2 networks of competing individuals. Social network analysis then allowed us to determine 1) the effectiveness of precopulatory competition for avoiding postcopulatory competition, 2) the potential for divergent mating strategies, and 3) whether increased postcopulatory competition reduces the apparent reproductive benefits of male promiscuity. We found 1) limited effectiveness of precopulatory competition for avoiding postcopulatory competition; 2) males do not specifically engage in only 1 type of competition; and 3) promiscuous individuals tend to mate with each other, which will tend to reduce variance in reproductive success in the population and highlights the trade-off inherent in mate guarding. Our results provide novel insights into the works of sexual competition in the wild. Furthermore, our study demonstrates the utility of using network analyses to study competitive interactions, even in species lacking obvious social structure.Funding for this research was provided by NERC (studentship no.:
NE/H02249X/1; grant no.: NE/H02364X/1). Further support
was provided by the University of Exeter’s Postgraduate Research
Enhancement Fund, awarded to D.N.F
Fertilisation and early developmental barriers to hybridisation in field crickets
This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Post-mating interactions between the reproductive traits and gametes of mating individuals and among their genes within zygotes are invariably complex, providing multiple opportunities for reproduction to go awry. These interactions have the potential to act as barriers to gene flow between species, and may be important in the process of speciation. There are multiple post-mating barriers to interbreeding between the hybridising field crickets Gryllus bimaculatus and G. campestris. Female G. bimaculatus preferentially store sperm from conspecific males when mated to both conspecific and heterospecific partners. Additionally, conspecific males sire an even greater proportion of offspring than would be predicted from their sperm's representation in the spermatheca. The nature of these post-sperm-storage barriers to hybridisation are unknown. We use a fluorescent staining technique to determine whether barriers occur prior to, or during embryo development. RESULTS: We show that eggs laid by G. bimaculatus females mated to G. campestris males are less likely to begin embryogenesis than eggs from conspecific mating pairs. Of the eggs that are successfully fertilised and start to develop, those from heterospecific mating pairs are more likely to arrest early, prior to blastoderm formation. We find evidence for bimodal variation among egg clutches in the number of developing embryos that subsequently arrest, indicating that there is genetic variation for incompatibility between mating individuals. In contrast to the pattern of early embryonic mortality, those hybrids reaching advanced stages of embryogenesis have survival rates equal to that of embryos from conspecific mating pairs. CONCLUSIONS: Post-sperm-storage barriers to hybridisation show evidence of genetic polymorphism. They are sufficiently large, that if the species interbreed where they are sympatric, these barriers could play a role in the maintenance of reproductive isolation between them. The number of eggs that fail to develop represents a substantial cost of hybridization to G. bimaculatus females, and this cost could reinforce the evolution of barriers occurring earlier in the reproductive process.This work was supported by the European Social Fund and the Natural Environment Research Council
Dynamic networks of fighting and mating in a wild cricket population
Acknowledgements We thank Paul Hopwood, Alex Thornton, Andrew Jackson and two anonymous referees for comments that improved this manuscript. We also thank Luke Meadows and Carlos Rodríguez del Valle for assistance with data collection. This work was supported by the Natural Environment Research Council (NERC, U.K.); studentship:NE/H02249X/1; standard grants: NE/E005403/1, NE/H02364X/1,NE/L003635/1, NE/R000328/1.Peer reviewedPublisher PD
High-pressure tuning of d-d crystal-field electronic transitions and electronic band gap in Co(I O3)2
High-pressure optical-absorption measurements performed on polycrystalline
Co
(
I
O
3
)
2
samples were used to characterize the influence of pressure on the electronic
d
–
d
transitions associated with
Co
2
+
and the fundamental band gap of
Co
(
I
O
3
)
2
. The results shed light on the electron-lattice coupling and show that
Co
(
I
O
3
)
2
exhibits an unusual behavior because the compression of Co–O bond distances is not coupled to pressure-induced changes induced in the unit-cell volume. Experimental results on the internal
d
–
d
transitions of
Co
2
+
have been explained based on changes in the constituent
Co
O
6
octahedral units using the semiempirical Tanabe-Sugano diagram. Our findings support that the high-spin ground state
(
4
T
1
)
is very stable in
Co
(
I
O
3
)
2
. We have also determined the band-gap energy of
Co
(
I
O
3
)
2
and its pressure dependence which is highly nonlinear. According to density-functional theory band-structure calculations, this nonlinearity occurs because the bottom of the conduction band is dominated by I-5p orbitals and the top of the valence band by Co-3d and O-2p orbitals, and because the Co–O and I–O bond lengths exhibit different pressure dependences.This work was supported by the Generalitat Valenciana under Project No. PROMETEO 2018/123-EFIMAT and by the Spanish Research Agency (AEI) and Spanish Ministry of Science and Investigation (MCIN) under Projects No. PID2019106383GB-C41/C43 (DOI: 10.13039/501100011033) cofinanced by EU FEDER funds, No. PGC2018-101464-B-I00, and No. RED2018-102612-T. A.L. and D.E. thank the Generalitat Valenciana for the Ph.D. Fellowship No. GRISOLIAP/2019/025. R.T. acknowledges funding from the Spanish MINECO via the Juan de la Cierva Formación program (Grant No. FJC2018-036185-I).
Biogas bioconversion into poly(3-hydroxybutyrate) by a mixed microbial culture in a novel Taylor flow bioreactor
Producción CientíficaBiogas-based biopolymer production represents an alternative biogas valorization route with potential to cut down plastic pollution and greenhouse gas emissions. This study investigated for the first time the continuous bioconversion of methane, contained in biogas, into poly(3-hydroxybutyrate) (PHB) by a mixed methanotrophic culture using an innovative high mass-transfer Taylor flow bioreactor. Following a hydrodynamic flow regime mapping, the influence of the gas residence time and the internal gas recirculation on CH4 abatement was assessed under non nutrient limiting conditions. Under optimal operational conditions (gas residence time of 60 min and internal gas recycling ratio of 17), the bioreactor was able to support a CH4 removal efficiency of 63.3%, a robust CH4 elimination capacity (17.2 g-CH4 m-3h-1) and a stable biomass concentration (1.0 g L-1). The simultaneous CH4 abatement and PHB synthesis was investigated under 24-h:24-h nitrogen feast/famine continuous operation. The cyclic nitrogen starvation and the Taylor flow imposed in the bioreactor resulted in a relatively constant biomass concentration of 0.6 g L-1 with PHB contents ranging from 11 to 32% w w-1 (on a dry weight basis), entailing an average PHB productivity of 5.9 g-PHB m-3 d-1 with an associated PHB yield of 19.8 mg-PHB g-CH4-1. Finally, the molecular analysis of the microbial population structure indicated that type II methanotrophs outcompeted non-PHB accumulating type I methanotrophs, with a heterotrophic-methanotrophic consortium enriched in Methylocystis, Hyphomicrobium, Rubinisphaeraceae SH PL14 and Pseudonocardia.Ministerio de Ciencia, Innovación y Universidades (project RTI2018-0-096441-B-I00)Erasmus+ International Master of Science in Environmental Technology and Engineering (project 2017-1957/001-001-EMJMD)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (grants CLU 2017-09 and UIC 315
La formación del profesorado en las tecnologías de la información y comunicación
[Resumen] La formación en TICs! y más específicamente
en Internet de los docentes es resaltada
en muchos informes y estudios de casos
nacionales e internacionales como el factor
causal por excelencia para entender la mejor
o peor integración de las TICs en las aulas.
El hecho de que los profesores estén
familiarizados a nivel personal con el uso de
las TICs e Internet, no implica automáticamente
que sepan cómo utilizarlos con fines
pedagógicos.
Con nuestra investigación pretendemos
establecer las especificaciones de un proyecto
de red2 informática educativa del
Municipio de A Coruña dentro del programa
"Descubrir la Informática" que se viene
desarrollando cada curso educativo desde
1998. En este caso nos centramos en una de
las secciones analizadas como es la formación
del profesorado[Abstrac] The formation in Tics and more specifically in Internet of the educational ones is emphasized in many information and studies of national and international cases like the causal factor par excellence to understand best or worse integration of the Tics in the classrooms. The fact that the professors are familiarized
at personal level with the use of the TIC
and Internet, does not imply automatically
that they know how to use them with pedagogical aims. With our investigation we try to establish the specifications of a project of educative computer science network of the Municipality of A Corunna within the program "To discover the Computer science" that comes developing each educative course from 1998. In this case we were centered in one of the analyzed sections as it is the lormation
oft he teaching staf
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