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In the process of ship motion control system design, it is necessary to take into account the impact of environmental disturbances such as winds, waves and sea currents. The commonly used representatives of wave influences in this area are the unidirectional wave power spectral density functions describing sea waves of different form: long-crested, fully developed waves, developing wind waves or multi-modal waves (e.g., with swell). The existing standard PSD models describe the surge of open sea or ocean. However, they are inadequate in the case of control system testing of scale ship models for sailing in open water areas such as lakes or test pools. This paper presents a study of wind-generated wave PSD estimations for a small lake used as a test area for free-running scale ships. The publication provides a brief overview of the wave spectral density functions commonly used for control system design. A measurement instrument using the idea of a water-induced variable capacitance that works synchronously with the wind sensors is also described. The process of collected data analysis is presented. As a result of the study, a series of empirical spectral density functions of lake waves for different wind speeds are obtained. They correspond to the rescaled, two-parametric ITTC model.

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An all fiber-optic immunosensor based on elliptical core helical intermediate-period fiber grating (E-HIPFG) is proposed for the specific detection of human immunoglobulin G (human IgG). E-HIPFGs are all-fiber transducers that do not include any additional coating materials or fiber architectures, simplifying the fabrication process and promising the stability of the E-HIPFG biosensor. For human IgG recognition, the surface of an E-HIPFG is functionalized by goat anti-human IgG. The functionalized E-HIPFG is tested by human IgG solutions with a concentration range of 10-100 µg/mL and shows a high sensitivity of 0.018 nm/(µg/mL) and a limit of detection (LOD) of 4.7 µg/mL. Notably, the functionalized E-HIPFG biosensor is found to be insensitive to environmental disturbances, with a temperature sensitivity of 2.6 pm/°C, a strain sensitivity of 1.2 pm/µÎµ, and a torsion sensitivity of -23.566 nm/(rad/mm). The results demonstrate the considerable properties of the immunosensor, with high resistance to environmental perturbations, indicating significant potential for applications in mobile biosensors and compact devices.

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The forces and moments acting on a marine vessel caused by the wind are most often modeled based on its speed measured at a standard 10 m above the sea level. There exist numerous well-known methods for modeling wind speed in such conditions. These models, by nature, are inadequate for simulating wind disturbances for free-running scale ship models sailing on lakes. Such scale models are being used increasingly for design and testing modern ship motion control systems. The paper describes the hardware and methodology used in measuring wind speed at low altitudes above the lake level. The system consists of two ultrasonic anemometers supplemented with wave sensor acting as a capacitor immersed partially in the water. Obtained measurement results show clear similarity to the values gathered during full-scale experiments. Analysis of the power spectral density functions of turbulence measured for different mean wind speeds over the lake, indicates that, at the present stage of research, the best model of wind turbulence at low altitude above the lake level can be obtained by assembling four of the known, standard turbulence models.

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This paper proposes a robust cooperative trajectory tracking control scheme for an unactuated floating object with multiple vessels under environmental disturbances. The object and multiple vessels are connected by using towlines. The proposed control scheme consists of three parts: a virtual controller for the object, a control allocation algorithm and a distributed robust time-varying formation controller for vessels. The virtual controller is first designed to obtain the control forces of the object to track the reference trajectory. To compute the optimal tension of each towline, the control allocation algorithm is introduced. Then, the time-varying relative positions from the object to vessels are gained by using a nonlinear towline model and the towline attachment geometry. Furthermore, the distributed robust time-varying formation controller is devised for vessels based on dynamic surface control technique, an adaptive law and graph theory. It is proved that the tracking errors of the object and vessels are bounded. Simulations substantiate that the proposed method can achieve good cooperative control performance and robustness, and the unactuated object can track the reference trajectory with high accuracy.

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An influential paradigm in coral reef ecology is that fishing causes trophic cascades through reef fish assemblages, resulting in reduced herbivory and thus benthic phase shifts from coral to algal dominance. Few long-term field tests exist of how fishing affects the trophic structure of coral reef fish assemblages, and how such changes affect the benthos. Alternatively, benthic change itself may drive the trophic structure of reef fish assemblages. Reef fish trophic structure and benthic cover were quantified almost annually from 1983 to 2014 at two small Philippine islands (Apo, Sumilon). At each island a No-Take Marine Reserve (NTMR) site and a site open to subsistence reef fishing were monitored. Thirteen trophic groups were identified. Large planktivores often accounted for >50% of assemblage biomass. Significant NTMR effects were detected at each island for total fish biomass, but for only 2 of 13 trophic components: generalist large predators and large planktivores. Fishing-induced changes in biomass of these components had no effect on live hard coral (HC) cover. In contrast, HC cover affected biomass of 11 of 13 trophic components significantly. Positive associations with HC cover were detected for total fish biomass, generalist large predators, piscivores, obligate coral feeders, large planktivores, and small planktivores. Negative associations with HC cover were detected for large benthic foragers, detritivores, excavators, scrapers, and sand feeders. These associations of fish biomass to HC cover were most clear when environmental disturbances (e.g., coral bleaching, typhoons) reduced HC cover, often quickly (1-2 yr), and when HC recovered, often slowly (5-10 yr). As HC cover changed, the biomass of 11 trophic components of the fish assemblage changed. Benthic and fish assemblages were distinct at all sites from the outset, remaining so for 31 yr, despite differences in fishing pressure and disturbance history. HC cover alone explained ~30% of the variability in reef fish trophic structure, whereas fishing alone explained 24%. Furthermore, HC cover affected more trophic groups more strongly than fishing. Management of coral reefs must include measures to maintain coral reef habitats, not just measures to reduce fishing by NTMRs.

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Microbial communities are continuously exposed to the arrival of alien species. In complex environments such as soil, the success of invasion depends on the characteristics of the habitat, especially the diversity and structure of the residing bacterial communities. While most data available on microbial invasion relies on experiments run under constant conditions, the fate of invading species when the habitat faces disturbances has not yet been addressed. Here, we designed experiments to assess the consequences of habitat disturbance on the success of ongoing microbial invasion. We investigated (i) if disturbance-induced alterations in resident microbial communities could mitigate or facilitate invasion of Listeria monocytogenes, (ii) if disturbance itself could either improve or reduce the invader's fitness and (iii) if the invading species alters the structure of indigenous microbial communities. Our data show that environmental disturbances affect invasion patterns of L. monocytogenes in soils. Intriguingly, successful invasion was recorded in a regimen of disturbances that triggered small changes in microbial community structure while maintaining high bacterial diversity. On the opposite, dramatic decline of the invader was recorded when disturbance resulted in emergence of specific communities albeit concomitant with a diversity loss. This suggests that community composition is more important than its diversity when it comes to prevent the establishment of an invading species. Finally, shifts in bacterial communities during the disturbance event were strengthened by the presence of the invader indicating a major impact of invasion on microbial diversity when the habitat faces disturbance.

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Over 2 yr, we assessed the health of 35 lowland tapirs (Tapirus terrestris) in the Brazilian Cerrado (CE) biome, an area that is highly affected by human activities. This involved physical examinations, hematology and blood biochemistry, urinalysis, fecal parasitologic evaluation, microbial profiling of anatomic cavities and lesions, and serologic surveys for evidence of infectious agents. Research methods closely resembled those used in previous tapir health assessments in the Atlantic Forest (AF) and Pantanal (PA) biomes, allowing for a comparison among the three populations. Although not reaching statistical significance (P>0.05), tapirs from the CE exhibited poorer body and skin condition as compared to animals from the AF and PA. Furthermore, there were higher prevalences of dental problems and traumatic lesions as compared to those from the AF and PA. Eight of the 12 hematologic parameters evaluated and 17 of the 30 biochemical parameters differed significantly (P<0.05) between the tapirs from CE and those from the AF and PA. We isolated 24 different microbiologic strains from swabs of anatomic cavities and dermal lesions, of which five taxa had not previously been found in the AF or PA. We detected serum antibodies to Leptospira interrogans, bluetongue virus, and porcine parvovirus. Overall, our results suggested that tapirs from the CE exhibited more health abnormalities than tapirs in the AF and PA, possibly due to a greater exposure to environmental disturbances in the area.

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Resumen La vegetación chaqueña esta condicionada por diversas presiones ambientales que afectan la fisionomía del paisaje. Con el objetivo de reconocer cambios espaciales de la vegetación y distinguir indicadores de disturbios naturales (inundaciones, sequías) y/o antrópicos (incendios, malezas de cultivos y pastoreo), se analizó la composición y distribución de las asociaciones polínicas de sedimentos superficiales sobre un gradiente ambiental al norte de la región chaqueña argentina (23°-27° S & 59°63° W). Se tomaron 35 muestras en un gradiente de 600 km en dirección SE-NO. El análisis se realizó con métodos multivariados y el índice de valor de importancia (IVI). La zonación mostró un reemplazo gradual de biotipos y taxones. En la zona oriental dominó el polen de palmeras (Copernica alba), hierbas (Poaceae) y árboles altos (Schinopsis balansae). Hacia la zona central predominó el polen de árboles bajos (Schinus, Prosopis ruscifolia, Pisonia zapallo), arbustos (Celtis, Castela) y hierbas (Amaranthaceae/Chenopodiaceae, Poaceae). La zona occidental presentó altos contenidos de polen de árboles altos (Schinopsis balansae, Schinopsis lorentzii, Astronium). Se detectaron conjuntos polínicos que permitieron discernir contingencias ambientales, como las inundaciones (Copernicia alba, Juncaginaceae, Cyperaceae) y actividades antrópicas, tales como incendios (Trithrinax, Shinus, Aspidosperma quebracho-blanco), malezas de cultivos (Amaranthaceae/ Chenopodiaceae, Gomphrena, Urticaceae, Ambrosia) y pastoreo (Prosopis ruscifolia, Prosopis kuntzei, Capparicordis, Cerciduim praecox). Los tipos polínicos más importantes fueron: Schinopsis balansae (9 %), Celtis (8.4 %), Poaceae (7.5 %), Schinus (6.9 %), Copernicia alba (3.7 %), entre otros. Se diferenciaron tres asociaciones polínicas que representaron las comunidades de: 1) palmares y sabanas, 2) bosques bajos y matorrales y 3) bosques altos, que se distribuyeron en umbrales de precipitación de 1 100 - 1 000, 1 000 -850 y 850 - 700 mm respectivamente. Los resultados amplían el conocimiento sobre las asociaciones polínicas de la región chaqueña argentina, ofreciendo una buena perspectiva para interpretar la dinámica del paisaje durante el Holoceno en la región.(AU)

Abstract Chaco vegetation is conditioned by several environmental pressures affecting the physiognomy of the landscape. With the aim to recognize the spatial changes of vegetation and distinguish indicators of natural (floods, droughts) and/or anthropogenic disturbances (fires, weeds of crops and grazing), we analyzed the composition and distribution of pollen assemblages of surface sediments along an environmental in the north of Argentine Chaco region (23°-27° S, 59°-63° W). Thirty-five samples were taken into an environmental gradient comprising 600 km length in SE-NW direction. The analyses was performed by multivariate methods and the importance value index (IVI). Zonation showed a gradual replacement of biotypes and taxa. In the Eastern zone, the pollen of palms (Copernica alba), herbs (Poaceae) and high trees (Schinopsis balansae) were dominant. Towards the middle zone, the pollen of low trees (Schinus, Prosopis ruscifolia, Pisonia zapallo), shrubs (Celtis, Castela) and herbs (Amaranthaceae/Chenopodiaceae, Poaceae) were dominant. The western zone recorded the highest content of pollen of high trees (Schinopsis balansae, Schinopsis lorentzii, Astronium). Pollen types were detected that allowed to discern environmental contingencies, such as floods (Copernicia alba, Juncaginaceae, Cyperaceae) and anthropic activities, such as fires (Trithrinax, Shinus, Aspidosperma quebracho-blanco), weeds of crops (Amaranthaceae/Chenopodiaceae, Gomphrena, Urticaceae, Ambrosia) and grazing (Prosopis ruscifolia, Prosopis kuntzei, Capparicordis, Cerciduim praecox). The most important pollen types were: Schinopsis balansae (9 %), Celtis (8.4 %), Poaceae (7.5 %), Schinus (6.9 %), Copernicia alba (3.7 %), among others. Three pollen assemblages were differentiated which represent the follow communities: 1) palms and savannas, 2) low forests and scrublands and 3) high forests, that are distributed in precipitation thresholds corresponding to, 1 100 - 1 000, 1 000 - 850 and 850 - 700 mm respectively. Results expand the knowledge about the pollen assemblages of the Argentine Chaco region, offering a good perspective to interpret the dynamic of the landscape during the Holocene in the region.(AU)

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We review current static and dynamic evolutionary game strategies of biological networks and discuss the lack of random genetic variations and stochastic environmental disturbances in these models. To include these factors, a population of evolving biological networks is modeled as a nonlinear stochastic biological system with Poisson-driven genetic variations and random environmental fluctuations (stimuli). To gain insight into the evolutionary game theory of stochastic biological networks under natural selection, the phenotypic robustness and network evolvability of noncooperative and cooperative evolutionary game strategies are discussed from a stochastic Nash game perspective. The noncooperative strategy can be transformed into an equivalent multi-objective optimization problem and is shown to display significantly improved network robustness to tolerate genetic variations and buffer environmental disturbances, maintaining phenotypic traits for longer than the cooperative strategy. However, the noncooperative case requires greater effort and more compromises between partly conflicting players. Global linearization is used to simplify the problem of solving nonlinear stochastic evolutionary games. Finally, a simple stochastic evolutionary model of a metabolic pathway is simulated to illustrate the procedure of solving for two evolutionary game strategies and to confirm and compare their respective characteristics in the evolutionary process.

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Natural disturbances in tropical forests modify the availability and quality of resources and alter the patterns of bird distribution. These environmental changes increase the metabolic rate and disrupt the redox balance promoting oxidative stress. This study aimed to compare the abundance of Willisornis poecilinotus between gaps and the understory of a forest with undisturbed canopy at Caxiuanã National Forest. The abundance was correlated with vegetation heights. The oxidative stress and the stress promoting factors were determined in both sites of sampling. We captured 81 specimens of W. poecilinotus. The number of captures was high in gaps. The specimens sampled at gaps showed high levels of oxidative stress. The biomarkers of oxidative stress were significantly correlated in gaps. The variability of oxidative stress and oxidative damage were explained only by site of sampling. These results suggest that gaps are stressors sites to W. poecilinotus, which probably can be due to an increase of metabolic rate to deal with new flight strategies of foraging and avoid predation.

Os distúrbios naturais nas florestas tropicais contribuem para heterogeneidade do habitat, alterando os padrões de distribuição das aves. Estas alterações no ambiente elevam o metabolismo, promovendo distúrbios no balanço redox, e em consequência o estresse oxidativo. O objetivo deste estudo foi comparar a abundância de Willisornis poecilinotus entre clareiras e sub-bosque de dossel intacto associando-a a altura da vegetação na Floresta Nacional de Caxiuanã. A seguir, foi avaliado o estresse oxidativo e os fatores promotores de estresse foram determinados nos ambientes selecionados. Foram capturados 81 espécimes de W. poecilinotus. O número de capturas foi superior nas clareiras, quando comparado ao sub-bosque de dossel contínuo. Os espécimes capturados nas clareiras apresentaram índices de estresse oxidativo significativamente elevados. Foi observada correlação significativa entre os marcadores de estresse oxidativo nas clareiras. As variações do biomarcador de dano oxidativo e do estresse oxidativo foram explicadas somente pelo sítio de amostragem. Estes resultados sugerem que as clareiras são sítios de estímulos estressores para W. poecilinotus o que provavelmente resulta da maior demanda metabólica para novas estratégias de forrageio e para evitar a predação.