3,755 research outputs found
Evolvability meets biogeography: evolutionary potential decreases at high and low environmental favourability
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this record.Understanding and forecasting the effects of environmental change on wild populations requires knowledge on a critical question: Do populations have the ability to evolve in response to that change? However, our knowledge on how evolution works in wild conditions under different environmental circumstances is extremely limited. We investigated how environmental variation influences the evolutionary potential of phenotypic traits. We used published data to collect or calculate 135 estimates of evolvability of morphological traits of European wild bird populations. We characterised the environmental favourability of each population throughout the speciesâ breeding distribution. Our results suggest that the evolutionary potential of morphological traits decreases as environmental favourability becomes high or low. Strong environmental selection pressures and high intra-specific competition may reduce speciesâ evolutionary potential in low and high favourability areas, respectively. This suggests that species may be least able to adapt to new climate conditions at their range margins and at the centre. Our results underscore the need to consider the evolutionary potential of populations when studying the drivers of species distributions, particularly when predicting the effects of environmental change. We discuss the utility of integrating evolutionary dynamics into a biogeographical perspective to understand how environmental variation shapes evolutionary patterns. This approach would also produce more reliable predictions about the effect of environmental change on population persistence and therefore on biodiversity.We acknowledge funding from the Spanish Ministerio de EconomĂa y Competitividad (grants CGL2012-34685, CGL2015-70639-P, and CGL2016-76173-P) and thanks to the ERA-Net BiodivERsA, with the national funder FCT (Project: BIODIVERSA/0003/2011). AE has a contract funded by the project 1098/2014 (Organismo AutĂłnomo Parques Nacionales, Spain)
Exergy cost assessment of solar trigeneration plant based on a concentrated solar power plant as the prime mover
An exergy cost assessment of solar trigeneration plant to generate electricity, fresh-water, and heat is carried out in order to study the process of exergy cost formation, to determine the key components that contribute to the cost of each product, and to establish the best configuration in term of unit exergy cost. The solar trigeneration plants evaluated consist of a concentrated solar power (CSP), a multi-effect distillation plant, and a process heat module, in which the CSP plant is the prime mover. The methodology includes modeling and evaluating the performance of standalone and trigeneration plants using the symbolic exergoeconomic methodology. Results show that the best configuration, in terms of exergy cost, is when the multi-effect distillation plant replaces the power cycle condenser. Regarding the costs formation, the key components which could be improved in their design are: solar collectors, evaporator, re-heater, dissipative systems, and productive subsystems
The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features
The black hole transient V404 Cygni exhibited a bright outburst in June 2015
that was intensively followed over a wide range of wavelengths. Our team
obtained high time resolution optical spectroscopy (~90 s), which included a
detailed coverage of the most active phase of the event. We present a database
consisting of 651 optical spectra obtained during this event, that we combine
with 58 spectra gathered during the fainter December 2015 sequel outburst, as
well as with 57 spectra from the 1989 event. We previously reported the
discovery of wind-related features (P-Cygni and broad-wing line profiles)
during both 2015 outbursts. Here, we build diagnostic diagrams that enable us
to study the evolution of typical emission line parameters, such as line fluxes
and equivalent widths, and develop a technique to systematically detect outflow
signatures. We find that these are present throughout the outburst, even at
very low optical fluxes, and that both types of outflow features are observed
simultaneously in some spectra, confirming the idea of a common origin. We also
show that the nebular phases depict loop patterns in many diagnostic diagrams,
while P-Cygni profiles are highly variable on time-scales of minutes. The
comparison between the three outbursts reveals that the spectra obtained during
June and December 2015 share many similarities, while those from 1989 exhibit
narrower emission lines and lower wind terminal velocities. The diagnostic
diagrams presented in this work have been produced using standard measurement
techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages
appendix with extra tables and figures. 18 figures are included in the paper
and 8 in the appendi
Hamiltonian Formulation of Scalar Field Collapse in Einstein Gauss Bonnet Gravity
We compute the Hamiltonian for spherically symmetric scalar field collapse in
Einstein-Gauss-Bonnet gravity in D dimensions using slicings that are regular
across future horizons. We first reduce the Lagrangian to two dimensions using
spherical symmetry. We then show that choosing the spatial coordinate to be a
function of the areal radius leads to a relatively simple Hamiltonian
constraint whose gravitational part is the gradient of the generalized mass
function. Next we complete the gauge fixing such that the metric is the
Einstein-Gauss-Bonnet generalization of non-static Painleve-Gullstrand
coordinates. Finally, we derive the resultant reduced equations of motion for
the scalar field. These equations are suitable for use in numerical simulations
of spherically symmetric scalar field collapse in Gauss-Bonnet gravity and can
readily be generalized to other matter fields minimally coupled to gravity.Comment: 14 pages, 0 figure
Investigating the loss of recruitment potential in red grouse (Lagopus lagopus scoticus) : the relative importance of hen mortality, food supply, tick infestation and louping-ill
Ticks and their pathogens cause significant disease
and economic loss in many animal populations. Despite
this, experiments that test the impact of ticks and tickborne
diseases on wild animal populations are rare. Here,
we report on an experiment assessing the effect of ticks
on red grouse productivity and chick growth in relation to
other causes of poor recruitment at two sites in the
Scottish uplands during 2005. Treated hens received two
leg bands impregnated with the acaricide permethrin,
while controls hens were untreated. Chicks were captured
at c.2 weeks of age and fitted with a metal patagial tag,
and chicks from treated hens also received a permethrinimpregnated
strip. Mean tick burdens in treated chicks
were close to zero compared with a mean of around 12
in the control group. Although treatment reduced tick
infestations, it did not increase brood size. Growth rates in
chicks from control and treated hens were similar during the first 10 days and comparable with chicks fed an ad-lib
invertebrate-based diet. These results suggest that in this case,
neither ticks (and the tick transmitted louping-ill virus) nor
food shortages was the main cause of chick mortality.
However, mortality in the adult hens was around 35 %, and
predation accounted for 62 % of these losses before broods
fledged. Our results indicate that on our study sites, predation
may have a more important impact on grouse population
dynamics than ticks and tick-borne disease. We suggest that
it may be more cost effective to determine the causes of poor
grouse population performance before implementing popular
but expensive tick control measures such as the culling
of alternative hosts and running acaracide treated sheep
âtick-mopâ flocks.http://link.springer.com/journal/10344hb201
Identification of genes responding to nematode infection in red grouse.
Abstract The identification of genes involved in a host's response to parasite infection provides both a means for understanding the pathways involved in immune defence and a target for examining host-parasite co-evolution. Most studies rely on a candidate gene approach derived from model systems to identify gene targets of interest, and there have been a dearth of studies geared towards providing a holistic overview of immune response from natural populations. We carried out an experiment in a natural population of red grouse (Lagopus lagopus scoticus) to manipulate levels of Trichostrongylus tenuis parasite infection. The transcriptomic response of individuals was examined from standard cDNA and suppressive subtractive hybridization (SSH) libraries produced from gut, liver and spleen, enriching for genes expressed in response to T. tenuis infection. A total of 2209 and 3716 unique transcript sequences were identified from the cDNA and SSH libraries, respectively. Forty-five of these had Gene Ontology annotation associated with immune response. Some of these genes have previously been reported from laboratory-based studies of model species as important in immune response to gastrointestinal parasite infection; however, multiple novel genes were also identified. These may reveal novel pathways involved in the host response of grouse to T. tenuis and provide a resource that can be utilized as candidate genes in other species
The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City
<p>Abstract</p> <p>Background</p> <p><it>Culex </it>spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, <it>Culex pipiens pipiens, Culex pipiens quinquefasciatus</it>, and <it>Culex tarsalis </it>are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of <it>Culex pipiens </it>complex mosquitoes and hybrids in Mexico City. <it>Culex pipiens pipiens </it>preferentially feed on avian hosts; <it>Culex pipiens quinquefasciatus </it>have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of <it>Culex pipiens </it>complex mosquitoes and their hybrids.</p> <p>Results</p> <p>Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as <it>Culex, Culiseta </it>or <it>Ochlerotatus </it>by morphological analysis. Within the genus <it>Culex</it>, specimens were further identified as <it>Culex tarsalis </it>or as belonging to the <it>Culex pipiens </it>complex. Members of the <it>Culex pipiens </it>complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the <it>Ace.2 </it>gene. <it>Culex pipiens quinquefasciatus </it>was the most abundant form collected.</p> <p>Conclusions</p> <p>Important WNV vectors species, <it>Cx. p. pipiens</it>, <it>Cx. p. quinquefasciatus </it>and <it>Cx. tarsalis</it>, are all present in Mexico City. Hybrids of <it>Cx. p. pipiens </it>and <it>Cx. p. quinquefasciatus </it>were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.</p
Identification of Colletotrichum species associated with anthracnose disease of coffee in Vietnam
Colletotrichum gloeosporioides, C. acutatum, C. capsici and C. boninense associated with anthracnose disease on coffee (Coffea spp.) in Vietnam were identified based on morphology and DNA analysis. Phylogenetic analysis of DNA sequences from the internal transcribed spacer region of nuclear rDNA and a portion of mitochondrial small subunit rRNA were concordant and allowed good separation of the taxa. We found several Colletotrichum isolates of unknown species and their taxonomic position remains unresolved. The majority of Vietnamese isolates belonged to C. gloeosporioides and they grouped together with the coffee berry disease (CBD) fungus, C. kahawae. However, C. kahawae could be distinguished from the Vietnamese C. gloeosporioides isolates based on ammonium tartrate utilization, growth rate and pathogenictity. C. gloeosporioides isolates were more pathogenic on detached green berries than isolates of the other species, i.e. C. acutatum, C capsici and C. boninense. Some of the C. gloeosporioides isolates produced slightly sunken lesion on green berries resembling CBD symptoms but it did not destroy the bean. We did not find any evidence of the presence of C. kahawae in Vietnam
Novel purine chemotypes with activity against Plasmodium 2 falciparum and Trypanosoma cruzi
Malaria and Chagas disease, caused by Plasmodium spp. and Trypanosoma cruzi parasites,
remain important global health problems. Available treatments for those diseases present several
limitations, such as lack of efficacy, toxic side effects, and drug resistance. Thus, new drugs are urgently needed. The discovery of new drugs may be benefited by considering the significant biological
differences between hosts and parasites. One of the most striking differences is found in the purine
metabolism, because most of the parasites are incapable of de novo purine biosynthesis. Herein,
we have analyzed the in vitro anti-P. falciparum and anti-T. cruzi activity of a collection of 81 purine
derivatives and pyrimidine analogs. We firstly used a primary screening at three fixed concentrations
(100, 10, and 1 ”M) and progressed those compounds that kept the growth of the parasites < 30%
at 100 ”M to doseâresponse assays. Then, we performed two different cytotoxicity assays on Vero
cells and human HepG2 cells. Finally, compounds specifically active against T. cruzi were tested
against intracellular amastigote forms. Purines 33 (IC50 = 19.19 ”M) and 76 (IC50 = 18.27 ”M) were
the most potent against P. falciparum. On the other hand, 6D (IC50 = 3.78 ”M) and 34 (IC50 = 4.24 ”M)
were identified as hit purines against T. cruzi amastigotes. Moreover, an in silico docking study
revealed that P. falciparum and T. cruzi hypoxanthine guanine phosphoribosyltransferase enzymes
could be the potential targets of those compounds. Our study identified two novel, purine-based
chemotypes that could be further optimized to generate potent and diversified anti-parasitic drugs
against both parasites.SAF2016-76080-R (Spanish Ministry of Economy
(AEI/FEDER, UE))PID2019-110810RB-I00 (Spanish Ministry of Science and Innovation)Generalitat of Catalonia Universities and Research
Department, Spain (AGAUR; 2017SGR00924)Carlos III Health Institute
(ISCIII)RICET Network for Cooperative Research in Tropical Diseases (ISCIII; RD12/0018/0010)Generalitat of Catalonia Department of Health (PERIS 2016â2010
SLT008/18/00132)Spanish Ministry of Education, Culture, and
Sports (FPU grant ref. 14/00818)Spanish Ministry of Science,
Innovation, and Universities through the âCentro de Excelencia Severo Ochoa 2019â2023â Program
(CEX2018-000806-S)CERCA Progra
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