83 research outputs found
Rigid Pavement as an Alternative to Flexible Pavement Failure in Ogbaru Swampy Area
The study deals on the influence of rural road construction and connectivity as one of the key components of Millennium Development goals, that creates access to economic and social service, promoting poverty alleviation by generating increased agricultural produce and employment opportunities in the rural areas. Rigid pavement stops the incessant incident of non accessibility of agricultural produce by deplorable state of flexible pavement of rural roads in Ogbaru Swampy area. Keywords: Rigid, flexible pavement, highway base course, subgrad
Impact of Human Urine Contamination on Soil Biota
The role of human urine as an organic pollutant to soil biota was examined in this study. Using
standard methods, the impact of human urine on the physicochemical parameters, fauna and
microbial load in the soil microcosm was considered. Ten replicates of Urine contaminated soil
(UrCS) and Uncontaminated Agricultural soil (UnCS) samples respectively were collected from
points pedestrian urine deposition within Olabisi Onabanjo University, Ago-Iwoye and
University of Agriculture, Alabata both in Ogun State. pH was determined using the pH meter.
Moisture content (MC) was determined by drying and difference in weight method. Organic
Carbon (OC) was determined using the Walkey-Black method and Organic Matter (OM) was
estimated by the formula %OC = %OC x 1.729. Phosphate and nitrate concentrations were
determined by spectrophotometric method while sulphate concentration was determined by
the turbidimetry method. Ammonium concentration was determined by distillation method
using 40% boric acid with methyl red indicator. The fauna record was conducted by heat
extraction into alcohol or normal saline while microbial load was estimated by the pour plate
and serial dilution techniques. UrCS recorded a significantly higher MC, OC, OM, phosphate,
nitrate, sulphate, ammonium concentrations and lower pH (p<0.05) than UnCS. A complete
absence of microfauna (protozoa), mesofauna (mites, lion ants, insects, insect eggs) and
macrofauna (beetle, beetle caterpillars, millipedes, pill millipedes, earthworms, earthworm
castings) was recorded in UrCS while UnCS samples recorded their presence. UrCS recorded a
significantly lower (p<0.05) microbial loads than UnCS. The most adverse impact of human
urine on soil biota is the lowered pH and increased acidity which unleash a vicious cycle on soil
biota persisting as long as urine deposition continues unhindered on the same spot
Male Mating Rate Is Constrained by Seminal Fluid Availability in Bedbugs, Cimex lectularius
Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition (sperm competition). Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently and differently for sperm and seminal fluid but empirical evidence for independent variation of sperm number and seminal fluid volume is scarce. It is also largely unknown how sperm and seminal fluid variation affect future mating rate. In bedbugs we developed a protocol to examine the role of seminal fluids in ejaculate allocation and its effect on future male mating rate. Using age-related changes in sperm and seminal fluid volume we estimated the lowest capacity at which mating activity started. We then showed that sexually active males allocate 12% of their sperm and 19% of their seminal fluid volume per mating and predicted that males would be depleted of seminal fluid but not of sperm. We tested (and confirmed) this prediction empirically. Finally, the slightly faster replenishment of seminal fluid compared to sperm did not outweigh the faster decrease during mating. Our results suggest that male mating rate can be constrained by the availability of seminal fluids. Our protocol might be applicable to a range of other organisms. We discuss the idea that economic considerations in sexual conflict research might benefit from distinguishing between costs and benefits that are ejaculate dose-dependent and those that are frequency-dependent on the mating rate per se
Sex differences in zonulin in affective disorders and associations with current mood symptoms
Zonulin measurement was funded by Institut Allergosan (Graz, Austria).Introduction: The bidirectional connection between the brain and the gut within psychiatric entities has gained increasing scientific attention over the last years. As a regulator of intestinal permeability, zonulin acts as a key player on the interface of this interplay. Like several psychiatric disorders, intestinal permeability was associated with inflammation in previous findings. Methods: In this study we explored differences in zonulin serum levels in currently depressed (n = 55) versus currently euthymic (n = 37) individuals with an affective disorder. Further, we explored sex differences and possible influences on zonulin and affective symptoms like medication, age, body mass index, and smoking status. Results: Serum zonulin was significantly higher in females than in men independent from affective status (z = -2.412, p = .016). More specifically, females in the euthymic subgroup had higher zonulin levels than euthymic men (z = -2.114, p = .035). There was no difference in zonulin serum levels in individuals taking or not taking a specific psychopharmacotherapy. We found no correlation between zonulin serum levels and depression severity. Discussion: Increased serum zonulin levels as a proxy for increased intestinal permeability in women may indicate a state of elevated susceptibility for depression-inducing stimuli.Publisher PDFPeer reviewe
Mite species inhabiting commercial bumblebee (Bombus terrestris) nests in Polish greenhouses
Nests of social insects are usually inhabited by various mite species that feed on pollen, other micro-arthropods or are parasitic. Well-known negative effects of worldwide economic importance are caused by mites parasitizing honeybee colonies. Lately, attention has focused on the endoparasitic mite Locustacarus buchneri that has been found in commercial bumblebees. However, little is known of other mites associated with commercial bumblebee nests. Transportation of commercial bumblebee colonies with unwanted residents may introduce foreign mite species to new localities. In this study, we assessed the prevalence and species composition of mites associated with commercial bumblebee nests and determined if the mites are foreign species for Poland and for Europe. The study was conducted on 37 commercial bumblebee nests from two companies (Dutch and Israeli), originating from two greenhouses in southern Poland, and on 20 commercial bumblebee colonies obtained directly from suppliers. The species composition and abundance of mites inhabiting commercial bumblebee nests were determined. Seven mite species from three families were found in nests after greenhouse exploitation. The predominant mite species was Tyrophagus putrescentiae (Acaridae) that was a 100-fold more numerous than representatives of the family Laelapidae (Hypoaspis marginepilosa, H. hyatti, H. bombicolens). Representatives of Parasitidae (Parasitellus fucorum, P. crinitus, P. ignotus) were least numerous. All identified mite species are common throughout Europe, foreign species were not found. Mites were not detected in nests obtained directly from suppliers. We conclude that probably bumblebee nests are invaded by local mite species during greenhouse exploitation
Understanding the enhanced synchronization of delay-coupled networks with fluctuating topology
We study the dynamics of networks with coupling delay, from which the connectivity changes over time. The synchronization properties are shown to depend on the interplay of three time scales: the internal time scale of the dynamics, the coupling delay along the network links and time scale at which the topology changes. Concentrating on a linearized model, we develop an analytical theory for the stability of a synchronized solution. In two limit cases the system can be reduced to an “effective” topology: In the fast switching approximation, when the network fluctuations are much faster than the internal time scale and the coupling delay, the effective network topology is the arithmetic mean over the different topologies. In the slow network limit, when the network fluctuation time scale is equal to the coupling delay, the effective adjacency matrix is the geometric mean over the adjacency matrices of the different topologies. In the intermediate regime the system shows a sensitive dependence on the ratio of time scales, and specific topologies, reproduced as well by numerical simulations. Our results are shown to describe the synchronization properties of fluctuating networks of delay-coupled chaotic maps
Maternal environment shapes the life history and susceptibility to malaria of Anopheles gambiae mosquitoes
BACKGROUND: It is becoming generally recognized that an individual's phenotype can be shaped not only by its own genotype and environmental experience, but also by its mother's environment and condition. Maternal environmental factors can influence mosquitoes' population dynamics and susceptibility to malaria, and therefore directly and indirectly the epidemiology of malaria. METHODS: In a full factorial experiment, the effects of two environmental stressors - food availability and infection with the microsporidian parasite Vavraia culicis - of female mosquitoes (Anopheles gambiae sensu stricto) on their offspring's development, survival and susceptibility to malaria were studied. RESULTS: The offspring of A. gambiae s.s. mothers infected with V. culicis developed into adults more slowly than those of uninfected mothers. This effect was exacerbated when mothers were reared on low food. Maternal food availability had no effect on the survival of their offspring up to emergence, and microsporidian infection decreased survival only slightly. Low food availability for mothers increased and V. culicis-infection of mothers decreased the likelihood that the offspring fed on malaria-infected blood harboured malaria parasites (but neither maternal treatment influenced their survival up to dissection). CONCLUSIONS: Resource availability and infection with V. culicis of A. gambiae s.s. mosquitoes not only acted as direct environmental stimuli for changes in the success of one generation, but could also lead to maternal effects. Maternal V. culicis infection could make offspring more resistant and less likely to transmit malaria, thus enhancing the efficacy of the microsporidian for the biological control of malaria
Using resting-state DMN effective connectivity to characterize the neurofunctional architecture of empathy
Neuroimaging studies in social neuroscience have largely relied on functional connectivity (FC) methods to characterize the functional integration between different brain regions. However, these methods have limited utility in social-cognitive studies that aim to understand the directed information flow among brain areas that underlies complex psychological processes. In this study we combined functional and effective connectivity approaches to characterize the functional integration within the Default Mode Network (DMN) and its role in self-perceived empathy. Forty-two participants underwent a resting state fMRI scan and completed a questionnaire of dyadic empathy. Independent Component Analysis (ICA) showed that higher empathy scores were associated with an increased contribution of the medial prefrontal cortex (mPFC) to the DMN spatial mode. Dynamic causal modelling (DCM) combined with Canonical Variance Analysis (CVA) revealed that this association was mediated indirectly by the posterior cingulate cortex (PCC) via the right inferior parietal lobule (IPL). More specifically, in participants with higher scores in empathy, the PCC had a greater effect on bilateral IPL and the right IPL had a greater influence on mPFC. These results highlight the importance of using analytic approaches that address directed and hierarchical connectivity within networks, when studying complex psychological phenomena, such as empathy.- This study was funded by BIAL Foundation (Grant number 87/12); by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Education and Science through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653); by the postdoctoral scholarship UMINHO/BPD/18/2017 and by the Portuguese Foundation for Science Doctoral scholarship (PD/BD/105963/2014). This work was conducted at Psychology Research Centre (UID/PSI/01662/2013), University of Minho
Pervasiveness of Parasites in Pollinators
Many pollinator populations are declining, with large economic and ecological
implications. Parasites are known to be an important factor in the some of the
population declines of honey bees and bumblebees, but little is known about the
parasites afflicting most other pollinators, or the extent of interspecific
transmission or vectoring of parasites. Here we carry out a preliminary
screening of pollinators (honey bees, five species of bumblebee, three species
of wasp, four species of hoverfly and three genera of other bees) in the UK for
parasites. We used molecular methods to screen for six honey bee viruses,
Ascosphaera fungi, Microsporidia, and
Wolbachia intracellular bacteria. We aimed simply to detect
the presence of the parasites, encompassing vectoring as well as actual
infections. Many pollinators of all types were positive for
Ascosphaera fungi, while Microsporidia were rarer, being
most frequently found in bumblebees. We also detected that most pollinators were
positive for Wolbachia, most probably indicating infection with
this intracellular symbiont, and raising the possibility that it may be an
important factor in influencing host sex ratios or fitness in a diversity of
pollinators. Importantly, we found that about a third of bumblebees
(Bombus pascuorum and Bombus terrestris)
and a third of wasps (Vespula vulgaris), as well as all honey
bees, were positive for deformed wing virus, but that this virus was not present
in other pollinators. Deformed wing virus therefore does not appear to be a
general parasite of pollinators, but does interact significantly with at least
three species of bumblebee and wasp. Further work is needed to establish the
identity of some of the parasites, their spatiotemporal variation, and whether
they are infecting the various pollinator species or being vectored. However,
these results provide a first insight into the diversity, and potential
exchange, of parasites in pollinator communities
- …