132 research outputs found

    Rigid Pavement as an Alternative to Flexible Pavement Failure in Ogbaru Swampy Area

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    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

    Female mouthbrooders in control of pre- and postmating sexual selection

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    The fertilization mode determines which sex has greater control over the offspring's sires. With internal fertilization, females can strongly influence the chances of different males' ejaculates to fertilize their eggs by the postmating sexual selection process referred to as cryptic female choice. In contrast, when fertilization is external and multiple males compete in this process, the outcome of pre- and postmating sexual selection is largely determined by the competitive quality of males and their sperm. Intermediate modes of fertilization as found in mouthbrooding fishes might allow for a greater maternal influence on her offspring's sire. Here, we show that in the maternal mouthbrooder Ophthalmotilapia ventralis, females collect sperm from different males in their mouth, and males can successfully fertilize eggs even if the female did not lay eggs with them. In the field, 25 of 30 clutches had multiple sires, and the fertilization success was significantly biased toward particular males in most clutches. A mate choice experiment revealed that females prefer to spawn with males possessing strongly elongated pelvic fins, a conspicuous secondary sexual character of males in this cichlid. Additionally, the body length of males partly explained their success in sperm competition within the females' mouth, a factor without apparent influence on female choice of partners with which to lay eggs. Hence, successful sires are determined by a 2-step process that is largely under female control; females select which males to spawn with and from which males they collect additional ejaculates for the subsequent sperm competition in their mout

    Eksistensi Nilai Pancasila Pada Generasi Milenial

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    Pancasila merupakan ideologi bangsa yang perlu ditanamkan tanpa terputus dari generasi pendahulu kepada generasi penerusnya, yang saat ini ada pada generasi milenial, tak terkecuali bagi para santriwati milenial yang berada di lingkungan pondok pesantren. Dengan eksistensi nilai Pancasila diharapkan dapat meningkatkan rasa persatuan antar santri dan bermasyarakat, berbingkai Negara Kesatuan Republik Indonesia. Tujuan kegiatan ini adalah untuk menanamkan nilai Pancasila kepada generasi milenial, khususnya kepada santriwati pondok pesantren putri Al-Awwabin, di Kelurahan Bedahan, Kecamatan Sawangan, Kota Depok, Jawa Barat sebagai mitra kegiatan. Dengan tertanamnya dengan baik nilai-nilai luhur ideologi Pancasila ini, diharapkan dapat lebih meningkatkan nilai persatuan dalam keberagaman yang ada pada diri masing-masing santriwati, serta mampu menangkal paham radikalisme yang ada di lingkungan pondok pesantren. Kegiatan penyuluhan ini diharapkan dapat menambah wawasan dan khasanah ilmu pengetahuan khususnya dalam penanaman karakter nilai persatuan dan tanggung jawab bersama di dalam kehidupan sehari-hari tiap individu maupun dalam bermasyarakat, dimana nilai egoistik individualisme kerap ditemukan lingkungan masyarakat, akibat derasnya pengaruh dari kemajuan teknologi, yang berakibat dapat merusak nilai moral dan persatuan dalam lingkungan pondok pesantren. Setelah kegiatan ini, ditemukan bahwa nilai Pancasila masih tertanam dengan baik di kalangan santriwati, yang dibuktikan dengan tanggapan atas kesadaran dalam bermasyarakat dan mampu menjawab pertanyaan yang berhubungan dengan nilai Pancasila

    Chaos synchronization by resonance of multiple delay times

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    Chaos synchronization may arise in networks of nonlinear units with delayed couplings. We study complete and sublattice synchronization generated by resonance of two large time delays with a specific ratio. As it is known for single-delay networks, the number of synchronized sublattices is determined by the greatest common divisor (GCD) of the network loop lengths. We demonstrate analytically the GCD condition in networks of iterated Bernoulli maps with multiple delay times and complement our analytic results by numerical phase diagrams, providing parameter regions showing complete and sublattice synchronization by resonance for Tent and Bernoulli maps. We compare networks with the same GCD with single and multiple delays, and we investigate the sensitivity of the correlation to a detuning between the delays in a network of coupled Stuart-Landau oscillators. Moreover, the GCD condition also allows detection of time-delay resonances, leading to high correlations in nonsynchronizable networks. Specifically, GCD-induced resonances are observed both in a chaotic asymmetric network and in doubly connected rings of delay-coupled noisy linear oscillators

    Strong and weak chaos in networks of semiconductor lasers with time-delayed couplings

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    Nonlinear networks with time-delayed couplings may show strong and weak chaos, depending on the scaling of their Lyapunov exponent with the delay time. We study strong and weak chaos for semiconductor lasers, either with time-delayed self-feedback or for small networks. We examine the dependence on the pump current and consider the question of whether strong and weak chaos can be identified from the shape of the intensity trace, the autocorrelations, and the external cavity modes. The concept of the sub-Lyapunov exponent λ0 is generalized to the case of two time-scale-separated delays in the system. We give experimental evidence of strong and weak chaos in a network of lasers, which supports the sequence of weak to strong to weak chaos upon monotonically increasing the coupling strength. Finally, we discuss strong and weak chaos for networks with several distinct sub-Lyapunov exponents and comment on the dependence of the sub-Lyapunov exponent on the number of a laser's inputs in a network

    The cost of promiscuity: sexual transmission of Nosema microsporidian parasites in polyandrous honey bees

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    Multiple mating (and insemination) by females with different males, polyandry, is widespread across animals, due to material and/or genetic benefits for females. It reaches particularly high levels in some social insects, in which queens can produce significantly fitter colonies by being polyandrous. It is therefore a paradox that two thirds of eusocial hymenopteran insects appear to be exclusively monandrous, in spite of the fitness benefits that polyandry could provide. One possible cost of polyandry could be sexually transmitted parasites, but evidence for these in social insects is extremely limited. Here we show that two different species of Nosema microsporidian parasites can transmit sexually in the honey bee Apis mellifera. Honey bee males that are infected by the parasite have Nosema spores in their semen, and queens artificially inseminated with either Nosema spores or the semen of Nosema-infected males became infected by the parasite. The emergent and more virulent N. ceranae achieved much higher rates of infection following insemination than did N. apis. The results provide the first quantitative evidence of a sexually transmitted disease (STD) in social insects, indicating that STDs may represent a potential cost of polyandry in social insects

    Sex differences in zonulin in affective disorders and associations with current mood symptoms

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    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

    Understanding the enhanced synchronization of delay-coupled networks with fluctuating topology

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    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

    Mite species inhabiting commercial bumblebee (Bombus terrestris) nests in Polish greenhouses

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    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
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