饲料污染物呕吐毒素对单胃动物家禽和猪肠道的影响(续)

2.4呕吐毒素对营养素肠道吸收的影响在饲喂呕吐毒素污染饲料的鸡中首次观察到D-葡萄糖等多种关键营养素的肠道转运和摄取受到影响,这种影响也与动物生长速度较差有关。不过,呕吐毒素对体内营养素吸收的影响知之甚少。

毛皮动物冬毛期的营养需要

1毛皮动物对营养物质的需求规律进入冬毛生长期后,毛皮动物对除能量外的各种营养物质的需求量"日渐恒定"。由于身体长度增加的最佳时期已经过去,寒冷的冬天逐渐来临,毛皮动物为了渡过漫长而寒冷的冬季,必须要储备足够的营养成分。因此,在这个阶段,毛皮动物所需要的各种营养成分的数量和质量相对而言还是比较高的。尽管个体还在逐渐地增大,但由于生长的速度已经放慢,并且,生长的主要部位不再是肌肉、骨骼和身体的长度。

Biomechanical research of knee joint during the process of running

To study the effect of speed on the biomechanics of a knee joint during running, a biomechanical model of human lower limb joints is established based on the Kane method and semi-physical simulation. Experiments on the running process were made at different speeds for healthy young men. The influence of running speed on knee Joint motion is analyzed quantitatively and a mathematical model of the knee angle is established with speed as the independent variable. Results show that, at the moment of the heel contacting with theground, with the increase of speed, the more, and the calf and thigh are closer to the same line. In the middle stage of a gait cycle, the thigh stretches back, and then the calf and thigh are close to collineation. At that moment, the stretch of the posterior cruciate ligament is the largest, and the slower the speed, the more obvious the collineation. The maximal joint angle of the calf relative to the thigh appears in the later stage, and themaximal joint angle increases with the increase of the velocity. With the increase of the running speed, the phase of the cure of knee angle moves forward. The results can be used in the field of rehabilitation robotics and humanoid robot.

Relation between basin morphometric features and dynamic characteristics of debris flows——a case study in Siberia, Russia

Extreme and prolonged rainfall in the Tunka Ridge caused several debris flows in the vicinity of the Arshan village(Siberia, Russia) on June 28, 2014. These debris flows, in spite of similar geological conditions, had different velocity, peak discharge and alluvial fan volume values. The flow velocity was from 3.5 m/s to 19.6 m/s, the peak discharge ranged from 63 m3/s to 13566 m3/s, and the alluvial fan volume varied from 4.13×103 to 8.45×105 m3. Such a great range of values is due to the morphometric parameters of the debris flow basins. The article deals with the influence of morphometric parameters of debris flow basins, such as the basin area, the average slope, Melton ratio, relief ratio on the debris flow velocity, peak discharge and volume of alluvial fans. In this debris flow event the average values of slope angle and total basin relief of the debris flow basins did not affect the values of debris flow velocity, peak discharge and alluvial fan volume. The highest correlations were observed with the debris flow basin area that was connected with the water inflow volume into the debris flow basins during the rainfall. The unequal water distribution among debris flow basins also had an impact on the debris flow velocity, peak discharge and volume of alluvial fans.

Effect of H_2S Flow Rate and Concentration on Performance of H_2S/Air Solid Oxide Fuel Cell

A solid state H2S/air electrochemical cell having the configuration of H2S, (MoS2+NiS+Ag)/YSZ/Pt, air has been examined with different H2S flow rates and concentrations at atmospheric pressure and 750-850 ℃. Performance of the fuel cell was dependent on anode compartment H2S flow rate and concentration. The cell open-circuit voltage increased with increasing H2S flow rate. It was found that increasing both H2S flow rate and H2S concentration improved current-voltage and power density performance. This is resulted from improved gas diffusion in anode and increased concentration of anodic electroactive species. Operation at elevated H2S concentration improved the cell performance at a given gas flow rate. However, as low as 5% H2S in gas mixture can also be utilized as fuel feed to cells. Highest current and power densities, 17500mA·cm-2 and 200mW·cm-2, are obtained with pure H2S flow rate of 50ml·min-1 and air flow rate of 100ml·min-1 at 850℃.

饲料中微量元素添加过量的危害及其合理应用

各种微量元素的合理摄入,可以增强养殖动物的免疫力,提升动物生长速度。饲料的生产过程中,会添加各种动物所需的微量元素,养殖场合理的搭配使用可以保证动物微量元素的摄入量。由于,饲料生产中微量元素添加过程,具有一定的复杂性,部分饲料的实际含量与标准不符,需要相关部门提高重视。1饲料中微量元素添加过量对动物造成的危害1.1铁饲料中的铁元素有较高的耐受性,对养殖动物的生长具有保障作用。

A gait generation and transition method for quadruped walking machine

In nature, quadrupeds as horses or cats change their gait to be suited to their motion speed. This fact is very important to realize smooth motion with different gaits. In this article a method of the gait transition for the quadruped walking machine is proposed. With analyzing the accustomed gaits of quadruped, some standard gaits and the relationships between duty factor and the phasic differences of the legs corresponding to the first leg could be concluded. With this, the gaits transferring could be continuous. Besides, celerity and on line method for generation and modifying gaits is studied, which can make the robot have a smooth motion to adapt the uncharted rough terrain.

Degradation of Wastewater Containing Nitrobenzene by High Gravity-Ultrasonic/Ozonation/Electrolysis Technology

The integrated high gravity-ultrasonic/ozonation/electrolysis technology was applied in the pretreatment of wastewater containing nitrobenzene. The effect ofpH value, high gravity factor, liquid flow-rate and electric current density on removal of COD and nitrobenzene compounds was investigated. Experimental results have determined the optimal pro- cess regime involving a high gravity factor of 100, an electric current density of 20 mA/cm2, a liquid flow-rate of 100 L/h, and an initial liquid pH value of 11. After the wastewater had been treated for 180 rain, the degradation of nitrobenzene and COD reached 99% and 80%, respectively, with the biochemical coefficient （BOD/COD） equating to 0.64, and the subse- quent treatment of wastewater could be carried out by conventional biochemical means. Compared with traditional aeration- ozone contactors, a rotating packed bed with high mass transfer characteristics could be used to increase the ozonation treat- ment efficiency.

Biology and Culture

Human beings do not live in nature, they live in culture. Contrary to biological evolution, which is based on genetic inheritance, cultural change is transmitted by instruction. Simple beginnings of culture have been observed in various animals. However, the much advanced human culture became possible by its transmission by language, and by its being cumulative. The concept of cultural change as a progressive process, popular by 18th and 19th centuries thinkers, is nowadays rejected, and the uniqueness of each culture stressed. Although, there are some similarities between biological evolution and cultural change, important differences between these processes are emphasized. The rapid rate of cultural change （especially its technological aspect）, as compared to the rate of biological evolution, is noted. In addition, some cultural changes led to new phenomena, which in a time of crisis can be annulled. The possible consequences of the different rate of these two processes for humans as individuals, and for their societies are discussed.

Study on the Marine Sedimentary Environment Evolution of the Southern Laizhou Bay Under the Impact of Port Projects

The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and ^(210)Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a^(-1). Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

Effect of approach run velocity on the optimal performance of the triple jump

Purpose： The purpose of this study was to determine the effect of horizontal and vertical velocities at the landing of the last step of approach run on the performance and optimal phase ratio of the triple jump. Methods： Three-dimensional kinematic data of 13 elite male triple jumpers were obtained during a competition. Computer simulations were performed using a biomechanical model of the triple jump to determine the longest actual distance using the optimal phase ratio with altered horizontal and vertical velocities at the landing of the last step of approach run. Results： The actual distance obtained using the optimal phase ratio significantly increased as the horizontal velocity at the landing of the last step of approach run increased （p = 0.001） and the corresponding downward vertical velocity decreased （p = 0.001）. Increasing horizontal velocity at the landing of the last step of approach run decreased optimal hop percentage and increased optimal jump percentage （p = 0.001）, while decreasing corresponding downward vertical velocity increased optimal hop percentage and decreased optimal jump percentage （p = 0.001）. Conclusion： The effects of the velocities at the landing of the last step of approach run on the optimal phase ratio were generally small and did not qualitatively alter optimal techniques.

Testing of the Exhaust Gases Temperature Difference （AT）

The purpose of this paper is to investigate the efficiency of the three way catalyst by testing the exhaust gases temperature difference （AT=Tinlet-Toutlet） at the inlet and outlet of the catalyst using different fuel mixtures. The tests were carried out on a catalyst engine, under full load conditions, using as a fuel gasoline and ethanol mixtures. During the test the CO and HC emissions were measured in different engine speeds （1000, 2000 and 3000 rpm） and different fuel mixtures. The catalyst inlet （Ti） and outlet （To） temperatures were also monitored. It has been noticed that the use of ethanol as fuel results in the CO and HC decrease, with simultaneous temperature difference decrease （AT） at the catalyst when the engine function under full load conditions.

Dynamics of the Currents in the Strait of Khuran in the Persian Gulf

The Strait of Khuran is among the most important marine habitats in the Persian Gulf. It is the location of the largest Avicennia Marina mangroves along the Persian Gulf shoreline and is a major nursery region for the fish and to breeding, wintering and migrant water birds. This paper presents dynamics of the currents in the Strait of Khuran using the current data collected by fixed current meters. The analysis of the data showed that the currents in the Strait of Khuran were highly dominated by tidal forcing with mixed semi diurnal behavior. The tidal currents were strong and reached to a maximum velocity of 123 cm/s in the spring tide. Tidal analysis showed that the tidal current constituents （M2, $2, N2, K1, O1） are dominant with M2 component as the major one. The tidal currents occurred basically along the strait. The results show a westward residual flow along the strait with an average of 5.6 cm/s during the study. The direction of the flow indicates that any pollution discharged into the industrial developing eastern part of the strait has the potential to affect the sensitive ecosystem in the western part.

超回路列车不是梦

超回路列车的时速有望超过飞机……异想天开？看完本文，你也许会改变想法。

Response of brown anoles Anolis sagrei to multimodal signals from a native and novel predator

Abstract Multiple studies have focused on the importance of single modalities （visual, auditory, olfactory） in eliciting anti-predator behavior, however multiple channels are often engaged simultaneously. While examining responses to multiple cues can potentially reveal more complex behavioral responses, little is known about how multimodal processing evolves. By contrasting response to familiar and novel predators, insights can be gained into the evolution of multimodal responses. We studied brown anoles＇ （Anolis sagrei） response to acoustic and visual predatory cues of a common potential predator, the great-tailed grackle Quiscalus mexicanus and to the American kestrel Falco sparverius, a species found in other populations but not present in our study population. We observed anole behavior before and after a stimulus and quantified rates of looking, display, and locomotion. Anoles increased their rate of locomotion in response to grackle models, an effect modulated by grackle vocalizations. No such response or modulation was seen when anoles were presented with kestrel stimuli. This suggests that the degree of sophistication of anole response to predators is experience dependent and that relaxed selection can result in reduced anti-predator response following loss of predators.

低水平电离辐射的生理益处

引言已有较多的资料报道了电离辐射对机体的有害影响。许多资料指出,哺乳动物受到中等剂量的电离辐射急性照射,如10～100拉德辐照后,可产生较少危害。关于微小剂量辐射效虚的报告则较散乱,且评价较少。有的资料指出,电离辐射对细胞,组织和机体有刺激作用,可能产生有利影响。综述有关资料后,发现低剂量电离辐射的反应模式和其它有潜在危害的因子(如抗菌素和其它药物、金属、物理因子)

Environmental factors determining growth of salamander larvae： A field study

Larval growth and survival of organisms are strongly influenced by abiotic and biotic factors, as demonstrated by ex- perimental studies performed under controlled laboratory or semi-natural conditions. Even if they have many advantages, ex- periments cannot cover the full complexity of natural conditions and field studies are needed for a better understanding of how environmental variation determines growth and development rate. Fire salamander Salamandra salamandra females give birth to larvae in a variety of habitats, both epigean and subterranean. In caves, salamander larvae successfully grow and metamorphose, but their growth is more than three times longer than in epigean streams and factors determining these differences require inves- tigation. We performed a field study to understand the factors related to the growth of fire salamander larvae in different envi- ronmental conditions, evaluating the relationship between environmental features and larval growth and differences between caves and epigean spring habitats. Both caves and epigean larvae successfully grew. Capture-mark-recapture allowed to individu- ally track individuals along their whole development, and measure their performance. Growth rate was significantly affected by environmental variables： larvae grew faster in environments with abundant invertebrates and few conspeciflcs. Taking into ac- count the effect of environmental variables, larval growth was significantly lower in caves. Food availability plays a different ef- fect in the two environments. Larval growth was positively related to the availability of invertebrates in epigean sites only. The development rate of hypogeous populations of salamanders is slower because of multiple parameters, but biotic factors play a much stronger role than the abiotic ones

The stress-velocity relationship of twinning partial dislocations and the phonon-based physical interpretation

The dependence of dislocation mobility on stress is the fundamental ingredient for the deformation in crystalline materials. Strength and ductility, the two most important properties characterizing mechanical behavior of crystalline metals, are in general governed by dislocation motion. Recording the position of a moving dislocation in a short time window is still challenging, and direct observations which enable us to deduce the speed-stress relationship of dislocations are still missing. Using large-scale molecular dynamics simulations, we obtain the motion of an obstacle-free twinning partial dislocation in face centred cubic crystals with spatial resolution at the angstrom scale and picosecond temporal information. The dislocation exhibits two limiting speeds: the first is subsonic and occurs when the resolved shear stress is on the order of hundreds of megapascal. While the stress is raised to gigapascal level, an abrupt jump of dislocation velocity occurs, from subsonic to supersonic regime. The two speed limits are governed respectively by the local transverse and longitudinal phonons associated with the stressed dislocation, as the two types of phonons facilitate dislocation gliding at different stress levels.

Modeling of growth stress gradient effect on the oxidation rate at high temperature

A new oxidation kinetics model is established for high-temperature oxidation. We assume that the interface reaction is fast enough and the oxidation rate is controlled by diffusion process at high temperature. By introducing the growth stress gradient we modify the classical oxidation parabolic law. The modified factor of the oxidation rate constant is a function of growth strain, environment oxygen concentration, and temperature. The modeling results show that the stress gradient effect on the oxidation rate cannot be ignored. Growth strain will dominate whether the stress gradient effect promotes or slows down the oxidation process. The stress gradient effect becomes weaker at higher temperature. This effect is amplified at higher concentrations of environmental oxygen. Applied mechanical loads do not affect the oxidation rate. This model is available for high temperature oxidation of metals and alloys.

Numerical simulation of cavitating flow around a slender body with slip boundary condition

In this paper, we perform a numerical simulation of the cavitating flow around an underwater hemispherical-head slender body running at a high speed. For the first time, the slip boundary condition is introduced into this problem, and we find that the slip boundary condition has a big influence on the cavitation in the flow-separation zone. By simulating the cavitating flow under different cavitation numbers, we demonstrate that the slip boundary condition can effectively reduce the intensity of cavitation, as represented by the length of cavitation bubbles. The present paper provides a new method for utilization of new surface materials to control the cavitation on the underwater moving objects.