Phallus eversion sexing in Phrynops geoffroanus (Testudines: Chelidae): a new non-invasive approach / Sexagem por eversão do falo em Phrynops geoffroanus (Testudines: Chelidae): uma nova abordagem não invasiva

Abstract The sexing of species is an important tool for population management. In tortoises and turtles, sexing is usually done according to secondary characteristics, such as plastron morphology or phallus eversion techniques. In this paper, we present the phallus eversion method and compare its efficiency to other existing techniques. This new method aims at shortening the management time and reducing the physical aftereffects on the animals, fostering the clinical and reproductive management of Geoffroy's side-necked turtle (Phrynops geoffroanus) and related species. A sample of fifty individuals was taken in the central region of Piauí state, Northeastern Brazil. The proposed method consisted of moving the head from its resting position. The methods achieving a success rate higher than 80% were compared to each other as for the stimulation time required for phallus eversion. The method as here proposed achieved 100% efficiency in the sex determination of specimens with a linear carapace length between 10 and 34 cm. Also, when compared to the second most efficient method, it substantially reduced the time needed for managing the specimens (91%), avoiding possible sequelae in the individuals handled.

Resumo A sexagem das espécies é uma ferramenta importante para o manejo populacional. Em tartarugas, cágados e jabutis, a sexagem geralmente é feita de acordo com características secundárias, como morfologia do plastrão ou técnicas de eversão do falo. Neste artigo, apresentamos o método de eversão do falo e comparamos sua eficiência com outras técnicas existentes. Este novo método visa encurtar o tempo de manejo e reduzir os efeitos colaterais físicos nos animais, promovendo o manejo clínico e reprodutivo do cágado-de-barbicha (Phrynops geoffroanus) e espécies relacionadas. Uma amostra de cinquenta indivíduos foi coletada na região central do estado do Piauí, Nordeste do Brasil. O método proposto consiste em remover a cabeça de sua posição de repouso. Os métodos que obtiveram índice de sucesso superior a 80% foram comparados entre si quanto ao tempo de estimulação necessário para a eversão do falo. O método aqui proposto alcançou 100% de eficiência na determinação do sexo de espécimes com comprimento de carapaça linear entre 10 e 34 cm. Além disso, quando comparado ao segundo método mais eficiente, reduziu substancialmente o tempo necessário para o manejo dos espécimes (91%), evitando possíveis sequelas nos indivíduos manuseados.

Phallus eversion sexing in Phrynops geoffroanus (Testudines: Chelidae): a new non-invasive approach

Abstract The sexing of species is an important tool for population management. In tortoises and turtles, sexing is usually done according to secondary characteristics, such as plastron morphology or phallus eversion techniques. In this paper, we present the phallus eversion method and compare its efficiency to other existing techniques. This new method aims at shortening the management time and reducing the physical aftereffects on the animals, fostering the clinical and reproductive management of Geoffroys side-necked turtle (Phrynops geoffroanus) and related species. A sample of fifty individuals was taken in the central region of Piauí state, Northeastern Brazil. The proposed method consisted of moving the head from its resting position. The methods achieving a success rate higher than 80% were compared to each other as for the stimulation time required for phallus eversion. The method as here proposed achieved 100% efficiency in the sex determination of specimens with a linear carapace length between 10 and 34 cm. Also, when compared to the second most efficient method, it substantially reduced the time needed for managing the specimens (91%), avoiding possible sequelae in the individuals handled.

Resumo A sexagem das espécies é uma ferramenta importante para o manejo populacional. Em tartarugas, cágados e jabutis, a sexagem geralmente é feita de acordo com características secundárias, como morfologia do plastrão ou técnicas de eversão do falo. Neste artigo, apresentamos o método de eversão do falo e comparamos sua eficiência com outras técnicas existentes. Este novo método visa encurtar o tempo de manejo e reduzir os efeitos colaterais físicos nos animais, promovendo o manejo clínico e reprodutivo do cágado-de-barbicha (Phrynops geoffroanus) e espécies relacionadas. Uma amostra de cinquenta indivíduos foi coletada na região central do estado do Piauí, Nordeste do Brasil. O método proposto consiste em remover a cabeça de sua posição de repouso. Os métodos que obtiveram índice de sucesso superior a 80% foram comparados entre si quanto ao tempo de estimulação necessário para a eversão do falo. O método aqui proposto alcançou 100% de eficiência na determinação do sexo de espécimes com comprimento de carapaça linear entre 10 e 34 cm. Além disso, quando comparado ao segundo método mais eficiente, reduziu substancialmente o tempo necessário para o manejo dos espécimes (91%), evitando possíveis sequelas nos indivíduos manuseados.

Phallus eversion sexing in Phrynops geoffroanus (Testudines: Chelidae): a new non-invasive approach.

The sexing of species is an important tool for population management. In tortoises and turtles, sexing is usually done according to secondary characteristics, such as plastron morphology or phallus eversion techniques. In this paper, we present the phallus eversion method and compare its efficiency to other existing techniques. This new method aims at shortening the management time and reducing the physical aftereffects on the animals, fostering the clinical and reproductive management of Geoffroy's side-necked turtle (Phrynops geoffroanus) and related species. A sample of fifty individuals was taken in the central region of Piauí state, Northeastern Brazil. The proposed method consisted of moving the head from its resting position. The methods achieving a success rate higher than 80% were compared to each other as for the stimulation time required for phallus eversion. The method as here proposed achieved 100% efficiency in the sex determination of specimens with a linear carapace length between 10 and 34 cm. Also, when compared to the second most efficient method, it substantially reduced the time needed for managing the specimens (91%), avoiding possible sequelae in the individuals handled.

Frustrated Bearings.

In a bearing state, touching spheres (disks in two dimensions) roll on each other without slip. Here we frustrate a system of touching spheres by imposing two different bearing states on opposite sides and search for the configurations of lowest energy dissipation. If the dissipation between contacts of spheres is viscous (with random damping constants), the angular momentum continuously changes from one bearing state to the other. For Coulomb friction (with random friction coefficients) in two dimensions, a sharp line separates the two bearing states and we show that this line corresponds to the minimum cut. Astonishingly, however, in three dimensions intermediate bearing domains that are not synchronized with either side are energetically more favorable than the minimum-cut surface. Instead of a sharp cut, the steady state displays a fragmented structure. This novel type of state of minimum dissipation is characterized by a spanning network of slipless contacts that reaches every sphere. Such a situation becomes possible because in three dimensions bearing states have four degrees of freedom.

Mapping the local viscosity of non-Newtonian fluids flowing through disordered porous structures.

Flow of non-Newtonian fluids through topologically complex structures is ubiquitous in most biological, industrial and environmental settings. The interplay between local hydrodynamics and the fluid's constitutive law determines the distribution of flow paths. Consequently the spatial heterogeneity of the viscous resistance controls mass and solute transport from the micron to the meter scale. Examples range from oil recovery and groundwater engineering to drug delivery, filters and catalysts. Here we present a new methodology to map the spatial variation of the local viscosity of a non-Newtonian fluid flowing through a complex pore geometry. We use high resolution image velocimetry to determine local shear rates. Knowing the local shear rate in combination with a separate measurement of the fluid's constitutive law allows to quantitatively map the local viscosity at the pore scale. Our experimental results-which closely match with three-dimensional numerical simulations-demonstrate that the exponential decay of the longitudinal velocity distributions, previously observed for Newtonian fluids, is a function of the spatial heterogeneity of the local viscosity. This work sheds light on the relationship between hydraulic properties and the viscosity at the pore scale, which is of fundamental importance for predicting transport properties, mixing, and chemical reactions in many porous systems.

A comparison of hydrological and topological watersheds.

We introduce the hydrological watershed, a watershed where water can penetrate the soil, and compare it with the topological watershed for a two-dimensional landscape. For this purpose, we measure the fractal dimension of the hydrological watershed for different penetration depths and different grid sizes. Through finite size scaling, we find that the fractal dimension is 1.31 ± 0.02 which is significantly higher than the fractal dimension of the topological watershed. This indicates that the hydrological watershed belongs to a new universality class. We also find that, as opposed to the topological watershed, the hydrodynamic watershed can exhibit disconnected islands.

Targeted Recovery as an Effective Strategy against Epidemic Spreading.

We propose a targeted intervention protocol where recovery is restricted to individuals that have the least number of infected neighbours. Our recovery strategy is highly efficient on any kind of network, since epidemic outbreaks are minimal when compared to the baseline scenario of spontaneous recovery. In the case of spatially embedded networks, we find that an epidemic stays strongly spatially confined with a characteristic length scale undergoing a random walk. We demonstrate numerically and analytically that this dynamics leads to an epidemic spot with a flat surface structure and a radius that grows linearly with the spreading rate.

Selection of strawberry cultivars with tolerance to Tetranychus urticae (Acari: Tetranychidae) and high yield under different managements.

Tetranychus urticae Koch (Acari: Tetranychidae) is considered the main pest of strawberry. Several factors can favor its development, among them the genotype susceptibility and cropping system. The aims of this study were to evaluate the agronomic performance of strawberry cultivars under different managements and to identify strawberry cultivars that meet tolerance to T. urticae and high fruit yield. Thirteen cultivars of strawberry ('Albion', 'Aleluia', 'Aromas', 'Camarosa', 'Camino Real', 'Campinas', 'Diamante', 'Dover', 'Festival', 'Seascape', 'Toyonoka', 'Tudla', and 'Ventana') under three managements (open field, low tunnel, and high tunnel) were evaluated. The T. urticae attack to different cultivars was influenced by managements, being low tunnel the one that provided higher infestations in the most evaluated cultivars. 'Camarosa' was the cultivar with the lower incidence of pest and 'Dover' had the higher infestation. The genotype most suitable for growing under different managements is the 'Festival' genotype, since it meets tolerance to T. urticae, high fruit yield, and phenotypic stability.

Confined sandpile in two dimensions: Percolation and singular diffusion.

We investigate the properties of a two-state sandpile model subjected to a confining potential in two dimensions. From the microdynamical description, we derive a diffusion equation, and find a stationary solution for the case of a parabolic confining potential. By studying the systems at different confining conditions, we observe two scale-invariant regimes. At a given confining potential strength, the cluster size distribution takes the form of a power law. This regime corresponds to the situation in which the density at the center of the system approaches the critical percolation threshold. The analysis of the fractal dimension of the largest cluster frontier provides evidence that this regime is reminiscent of gradient percolation. By increasing further the confining potential, most of the particles coalesce in a giant cluster, and we observe a regime where the jump size distribution takes the form of a power law. The onset of this second regime is signaled by a maximum in the fluctuation of energy.

Majority-vote model on spatially embedded networks: Crossover from mean-field to Ising universality classes.

We study through Monte Carlo simulations and finite-size scaling analysis the nonequilibrium phase transitions of the majority-vote model taking place on spatially embedded networks. These structures are built from an underlying regular lattice over which directed long-range connections are randomly added according to the probability P_{ij}∼r^{-α}, where r_{ij} is the Manhattan distance between nodes i and j, and the exponent α is a controlling parameter [J. M. Kleinberg, Nature (London) 406, 845 (2000)NATUAS0028-083610.1038/35022643]. Our results show that the collective behavior of this system exhibits a continuous order-disorder phase transition at a critical parameter, which is a decreasing function of the exponent α. Precisely, considering the scaling functions and the critical exponents calculated, we conclude that the system undergoes a crossover among distinct universality classes. For α≤3 the critical behavior is described by mean-field exponents, while for α≥4 it belongs to the Ising universality class. Finally, in the region where the crossover occurs, 3<α<4, the critical exponents are dependent on α.

Crumpling Damaged Graphene.

Through molecular mechanics we find that non-covalent interactions modify the fractality of crumpled damaged graphene. Pristine graphene membranes are damaged by adding random vacancies and carbon-hydrogen bonds. Crumpled membranes exhibit a fractal dimension of 2.71 ± 0.02 when all interactions between carbon atoms are considered, and 2.30 ± 0.05 when non-covalent interactions are suppressed. The transition between these two values, obtained by switching on/off the non-covalent interactions of equilibrium configurations, is shown to be reversible and independent on thermalisation. In order to explain this transition, we propose a theoretical model that is compatible with our numerical findings. Finally, we also compare damaged graphene membranes with other crumpled structures, as for instance polymerised membranes and paper sheets, that share similar scaling properties.

Complex networks from space-filling bearings.

Two-dimensional space-filling bearings are dense packings of disks that can rotate without slip. We consider the entire first family of bearings for loops of four disks and propose a hierarchical construction of their contact network. We provide analytic expressions for the clustering coefficient and degree distribution, revealing bipartite scale-free behavior with a tunable degree exponent depending on the bearing parameters. We also analyze their average shortest path and percolation properties.

Fragmentation processes in two-phase materials.

We investigate the fragmentation process of solid materials with crystalline and amorphous phases using the the discrete element method. Damage initiates inside spherical samples above the contact zone in a region where the circumferential stress field is tensile. Cracks initiated in this region grow to form meridional planes. If the collision energy exceeds a critical value which depends on the material's internal structure, cracks reach the sample surface resulting in fragmentation. We show that this primary fragmentation mechanism is very robust with respect to the internal structure of the material. For all configurations, a sharp transition from the damage to the fragmentation regime is observed, with smaller critical collision energies for crystalline samples. The mass distribution of the fragments follows a power law for small fragments with an exponent that is characteristic for the branching merging process of unstable cracks. Moreover this exponent depends only on the dimensionally of the system and not on the microstructure.

Influence of age and gender in the normal values of Sino Nasal Outcome Test-22.

OBJECTIVES: Sino Nasal Outcome Test (SNOT)-22 is a disease-specific outcomes measure questionnaire that combines rhinologic issues with general health issues. These issues may have variable weight on quality of life perception, and the influence of several factors such as gender, ethnicity, age, socio-cultural status and co-morbidities is unknown. The aim of this study was to evaluate the influence of gender and age on normal values of SNOT-22. DESIGN: Cross-sectional study based on application of SNOT-22 questionnaires to healthy volunteers. Participants were divided according to gender, and each gender was subdivided into age groups: 18-30 years, 31-40 years, 41-50 years, 51-60 years and over 60 years. SETTING: Rhinology Section, Sao Paulo Federal University. PARTICIPANTS: A total of 539 healthy volunteers (253 men and 286 women) were selected, so that each age group of each gender consisted of at least 50 individuals. MAIN OUTCOMES MEASURES: We applied SNOT-22 questionnaire to volunteers with no nasal or sinus disease. Median of score distribution was used as normal reference. RESULTS: Men presented lower scores than women (7 versus 9, P = 0.005). Subjects over 60 years presented significantly lower scores than other age groups (18-30 years = 10; 31-40 years = 8; 41-50 years = 9; 51-60 years = 9; over 60 years = 7). Men presented lower scores than women especially in 41-50 year and 51-60 year groups. CONCLUSION: Men and elderly presented the lowest Brazilian version SNOT-22 scores. The range of 0-8 points seemed to be more suitable as a normal value for this instrument, but this cut-off score could be tailored to age and gender specificities.

Modelling the influence of photospheric turbulence on solar flare statistics.

Solar flares stem from the reconnection of twisted magnetic field lines in the solar photosphere. The energy and waiting time distributions of these events follow complex patterns that have been carefully considered in the past and that bear some resemblance with earthquakes and stockmarkets. Here we explore in detail the tangling motion of interacting flux tubes anchored in the plasma and the energy ejections resulting when they recombine. The mechanism for energy accumulation and release in the flow is reminiscent of self-organized criticality. From this model, we suggest the origin for two important and widely studied properties of solar flare statistics, including the time-energy correlations. We first propose that the scale-free energy distribution of solar flares is largely due to the twist exerted by the vorticity of the turbulent photosphere. Second, the long-range temporal and time-energy correlations appear to arise from the tube-tube interactions. The agreement with satellite measurements is encouraging.

Breathing synchronization in interconnected networks.

Global synchronization in a complex network of oscillators emerges from the interplay between its topology and the dynamics of the pairwise interactions among its numerous components. When oscillators are spatially separated, however, a time delay appears in the interaction which might obstruct synchronization. Here we study the synchronization properties of interconnected networks of oscillators with a time delay between networks and analyze the dynamics as a function of the couplings and communication lag. We discover a new breathing synchronization regime, where two groups appear in each network synchronized at different frequencies. Each group has a counterpart in the opposite network, one group is in phase and the other in anti-phase with their counterpart. For strong couplings, instead, networks are internally synchronized but a phase shift between them might occur. The implications of our findings on several socio-technical and biological systems are discussed.

Chronic unpredictable mild stress alters an anxiety-related defensive response, Fos immunoreactivity and hippocampal adult neurogenesis.

Previous results show that elevated T-maze (ETM) avoidance responses are facilitated by acute restraint. Escape, on the other hand, was unaltered. To examine if the magnitude of the stressor is an important factor influencing these results, we investigated the effects of unpredictable chronic mild stress (UCMS) on ETM avoidance and escape measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to map areas activated by stress exposure in response to ETM avoidance and escape performance. Additionally, the effects of the UCMS protocol on the number of cells expressing the marker of migrating neuroblasts doublecortin (DCX) in the hippocampus were investigated. Corticosterone serum levels were also measured. Results showed that UCMS facilitates ETM avoidance, not altering escape. In unstressed animals, avoidance performance increases Fos-ir in the cingulate cortex, hippocampus (dentate gyrus) and basomedial amygdala, and escape increases Fos-ir in the dorsolateral periaqueductal gray and locus ceruleus. In stressed animals submitted to ETM avoidance, increases in Fos-ir were observed in the cingulate cortex, ventrolateral septum, hippocampus, hypothalamus, amygdala, dorsal and median raphe nuclei. In stressed animals submitted to ETM escape, increases in Fos-ir were observed in the cingulate cortex, periaqueductal gray and locus ceruleus. Also, UCMS exposure decreased the number of DCX-positive cells in the dorsal and ventral hippocampus and increased corticosterone serum levels. These data suggest that the anxiogenic effects of UCMS are related to the activation of specific neurobiological circuits that modulate anxiety and confirm that this stress protocol activates the hypothalamus-pituitary-adrenal axis and decreases hippocampal adult neurogenesis.

Optimal transport exponent in spatially embedded networks.

The imposition of a cost constraint for constructing the optimal navigation structure surely represents a crucial ingredient in the design and development of any realistic navigation network. Previous works have focused on optimal transport in small-world networks built from two-dimensional lattices by adding long-range connections with Manhattan length r(ij) taken from the distribution P(ij)~r(ij)(-α), where α is a variable exponent. It has been shown that, by introducing a cost constraint on the total length of the additional links, regardless of the strategy used by the traveler (independent of whether it is based on local or global knowledge of the network structure), the best transportation condition is obtained with an exponent α=d+1, where d is the dimension of the underlying lattice. Here we present further support, through a high-performance real-time algorithm, on the validity of this conjecture in three-dimensional regular as well as in two-dimensional critical percolation clusters. Our results clearly indicate that cost constraint in the navigation problem provides a proper theoretical framework to justify the evolving topologies of real complex network structures, as recently demonstrated for the networks of the US airports and the human brain activity.

Optimal synchronizability of bearings.

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine-tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, m~r(α), with an optimal exponent α=α(×) which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors.

A first principles calculation of the oxygen uptake in the human pulmonary acinus at maximal exercise.

It has recently been shown that the acinus can have a reduced efficiency due to a "screening effect" governed by the ratio of oxygen diffusivity to membrane permeability, the gas flow velocity, as well as the size and configuration of the acinus. We present here a top to bottom calculation of the functioning of a machine acinus at exercise that takes this screening effect into account. It shows that, given the geometry and the breathing dynamics of real acini, respiration can be correlated to a single equivalent parameter that we call the integrative permeability. In particular we find that both V(O(2,max)) and PA(O(2)) depend on this permeability in a non-linear manner. Numerical solutions of dynamic convection-diffusion equations indicate that only a narrow range of permeability values is compatible with the experimental measurements of PA(O(2)) and V(O(2,max)). These permeability values are significantly smaller than those found in the literature. In a second step, we present a new type of evaluation of the diffusive permeability, yielding values compatible with the top to bottom approach, but smaller than the usual morphometric value.