1,009 research outputs found
Deterioration modeling of steel moment resisting frames using finite-length plastic hinge force-based beam-column elements
Is leg kicking workout position affecting kinematic and hydrodynamic variables in front-craw?
Swimming training includes leg kicking workouts, whereas
swimmerschoose betweenhead out (RO) or headin (HI) position
holding afllitter kick board. Ourobjective was to characterize
andanalyse differences between the t\vo legkicking positions in
Swimming Vdocity (Y, 1n m/s), lntra-cyclic variation of the
horizontal velocity (dv, dimensionless), Active Drag (D, in N),
Hydrodynamic Coefficient (CD •. dimensionless), Mechanical
Power (P, in W) andfrontal surfacearea (FSA, ia m2). Thirteen
swimmers (15.3 ± 2,9 years~old) participated in thisstudy.
Frontal surface area was calculated according to the proposal of
Morais et aI. (201l)byphotogrammetry. Aftefa standard warmup,
swimmers performed 4x25mbouts at maximum velocity as
follows: i) 2XcrawI HO Ieg-kick; ii) 2XcrawI HI Ieg-kick. ln the
first bout ofeach the V and the dv were measured usingaspeedmeter
cable that Was attached to lhe swimmer's hip (Barbosaet
aI., 2013). In the secondbout CD was obtained through the
velocity perturbation method (Kolmogorov and Duplishcheva,
1992).info:eu-repo/semantics/publishedVersio
Water regimes and bean cultivar effects on the soil porous system characteristics
Bean (Phaseolus vulgaris L.) is a crop of great economic and social impacts in Brazil. This crop is extremely appreciated by the Brazilian population and an important source of protein. Usually the small farmers are responsible by the largest production of the bean in Brazil. This work deals with the analysis of the effect of different water regimes (35, 28, 21 and 14%) on the porous system of a soil cropped with two distinct cultivars (Campos Gerais and Tuiuiú). Soil water retention curve (SWRC) and its derivative were utilized with the aim of investigating the changes in the porous system. Pore size distribution was also evaluated. The experiment was carried out at a greenhouse and the soil water content for the different water regimes was monitored by means of a TDR. Four undisturbed samples were collected from each wooden bed (eight) for the physic-hydrical characterization. Discrepancies in the SWRC were noticed for the region of small pressure heads. Differences were not observed between bean cultivars to SWRC. However, the water capacity function was sensitive to show differences in the soil porous system due to the treatments and cultivars. The lowest water regimes promoted the highest volume of fissures (big pores >250 µm) and, consequently, the highest ones had the largest volume of storage pores (<25 µm)
A new subspecies of Adelpha messana (C. Felder & R. Felder) from the Brazilian Atlantic forest (Nymphalidae: Limenitidinae)
Article published in the journal Tropical Lepidoptera Research
Morphology And Behavior Of The Early Stages Of The Skipper, Urbanus Esmeraldus, On Urera Baccifera, An Ant-visited Host Plant.
The Neotropical genus Urbanus (Hübner) (Lepidoptera: Hesperiidae) contains around 34 described species, and is widely distributed from the extreme southern United States to Argentina. Here, we describe the larval morphology and behavior of Urbanus esmeraldus (Hübner)(Hesperiidae) in Urera baccifera (Urticaceae), a plant producing food rewards and fleshy fruits that attract ants (including predacious species) in a Brazilian forest. Larvae pass through five instars and construct two kinds of leaf shelters. Experiments with ejected fecal pellets showed that these can serve as cues to ground-dwelling ants that climb onto host plants and potentially attack the larvae. Manipulation with pellets placed at different distances suggests that ejection behavior decreases larval vulnerability to ant predation. Larval preference for mature leaves may be related with increased predation risk at ant-visited young leaves. The study shows that a combination of natural history and experimental data can help understand the life history of a butterfly using a plant with high predation risk.125
Acute ischemic preconditioning does not influence high-intensity intermittent exercise performance
This study evaluated the acute effect of ischemic preconditioning (IPC) on a high-intensity intermittent exercise performance and physiological indicators in amateur soccer players. Thirteen players (21.5 ± 2 yrs) attended three trials separated by 3–5 days in a counterbalanced randomized cross-over design: IPC (4 × 5-min occlusion 220 mmHg/reperfusion 0 mmHg) in each thigh; SHAM (similar to the IPC protocol but “occlusion” at 20 mmHg) and control (seated during the same time of IPC). After 6-min of each trial (IPC, SHAM or control), the players performed the YoYo Intermittent Endurance Test level 2 (YoYoIE2). The distance covered in the YoYoIE2 (IPC 867 ± 205 m; SHAM 873 ± 212 m; control 921 ± 206 m) was not different among trials (p = 0.10), furthermore, lactate concentration and rate of perceived exertion did not differ (P > 0.05) among protocols. There were also no significant differences in either mean heart rate (HR) or peak HR (p > 0.05) for both IPC and SHAM compared to control. Therefore, we conclude that acute IPC does not influence high-intensity intermittent exercise performance in amateur soccer players and that rate of perceived exertion, heart rate and lactate do not differ between the intervention IPC, SHAM and control
On the nature of the (de)coupling of the magnetostructural transition in ErSi
In this report, a successful thermodynamical model was employed to understand
the structural transition in ErSi, able to explain the decoupling of
the magnetic and structural transition. This was achieved by the DFT
calculations which were used to determine the energy differences at 0 K, using
a LSDA+U approximation. It was found that the M structure as the stable phase
at low temperatures as verified experimentally with a 0.262 eV.
Finally, it was achieved a variation of Seebeck coefficient ( 6 V)
at the structural transition which allow to conclude that the electronic
entropy variation is negligible in the transition.Comment: 17 pages, 3 figures, 1 tabl
Application of reliability-based robustness assessment of steel moment resisting frame structures under post-mainshock cascading events
This paper proposes a reliability-based framework for quantifying structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of three, nine, and 20 stories, which were designed to pre-Northridge codes and standards. Two-dimensional nonlinear finite-element models of the buildings are developed with the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability based robustness indicator shows that the structural robustness is influenced by the extent to which a structure can distribute damage
All-Optical Amplitude Multiplexing Through Fiber Parametric Interaction Between Binary Signals
Application of reliability-based robustness assessment of steel moment resisting frame structures under post-mainshock cascading events
This paper proposes a reliability-based framework for quantifying structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of three, nine, and 20 stories, which were designed to pre-Northridge codes and standards. Two-dimensional nonlinear finite-element models of the buildings are developed with the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability based robustness indicator shows that the structural robustness is influenced by the extent to which a structure can distribute damage
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