Energetics of running cockroaches

Male cockroaches Gromphadorhina portentosa were made to run at 0.03, 0.07, and 0.12 kilometer per hour on a miniature treadmill within a small respirometer. Oxygen consumption was directly related to running velocity. The half-time necessary for oxygen consumption to reach a steady state during exercise was about 1 minute and the half-time for recovery was 4 to 6 minutes. The energetic cost of transport was comparable to that for bipedal and quadrupedal vertebrates.     

Training and maintenance of keypecking in the pigeon by negative reinforcement

Pigeons were trained to peck a key to escape a pulsing shock of linearly increasing intensity. As the rate of increase was varied from 0.0374 milliamperes per minute to 37.4 milliamperes per minute, the intensity at which most pecking occurred varied from 2.2 to 5.0 milliamperes.     

Internal winds in water lilies: an adaptation for life in anaerobic sediments

The network of internal gas spaces in the yellow water lily constitutes a pressurized flow-through system which forces oxygen to the roots and rhizome buried in the anaerobic sediment. By the purely physical processes of thermal transpiration and hygrometric pressure, several liters of air per day enter the young, newly emerged leaves of Nuphar luteum against a small pressure gradient. This air moves en masse down the petioles of the young leaves (at rates up to 50 centimeters per minute) to the rhizome, forcing a simultaneous flow of gas (rich in carbon dioxide) from the rhizome up the petioles of the older emergent leaves to the atmosphere. The ventilation system has important physiological and ecological consequences.     

通风速率对土壤中四氯化碳污染物去除效率的影响研究

某重要岩溶地下水源地受到四氯化碳的严重污染,为此采用土柱通风试验模拟土壤气相抽提(SVE)净化四氯化碳污染物的过程,对通风速率为40mL·min-1和70mL·min-1两种条件下土壤四氯化碳的去除过程进行了试验模拟研究。结果表明,土柱通风能有效去除土壤中的四氯化碳污染物,通风条件下土壤中四氯化碳的去除过程符合一级反应动力学,土壤中四氯化碳浓度C的对数值ln[C(/μg·L-1)]与时间t呈良好的线性关系,相关系数均在0.95以上。通风速率为40mL·min-1的土柱A各取样口四氯化碳去除反应速率常数k值在0.0132～0.0155h-1之间,通风速率为70mL·min-1的土柱B各取样口k值在0.0178～0.0222h-1之间,说明增大通风速率能提高土壤中四氯化碳污染物的去除效率。     

Radiuin-226 and radon-222 in the coastal waters of west Florida: high concentrations and atmospheric degassing

On the central portion of the west Florida continental shelf, radionuclide activities show unusually wide variations: radium-226 activities up to 350 disintegrations per minute per 100 liters, radon-222 activities up to 1300 disintegrations per minute per 100 liters, and deficiencies of radon-222 as low as -10 disintegrations per minute per 100 liters. Florida's phosphate-rich strata seerm to be the principal source of the radionuclides, with the transfer occurring directly from sediments or indirectly in streams, ground-water flow, and geothermal springs. Winter storm fronts may enhance radon degassing in the shelf waters.     

Acetylcholine liberation from cerebral cortex during paradoxical (REM) sleep

The rate of liberation of free acetylcholine from the surface of prostigmin-treated cerebral cortex in the freely moving cat has been determined in states of slow wave sleep, paradoxical or activated sleep, and waking. The average rate during slow wave sleep (1.2 nanograms per minute per square centimeter of cortical surface) increased during paradoxical sleep (2.2 nanograms per minute) and during waking (2.1 nanograms per minute). The rate of acetylcholine release is thus related to the electroencephalogram pattern of desynchronized activatin of the cortex rahter than to the behavioral responsiveness of the animals.     

Neuronal perikarya of rat brain isolated by zonal centrifugation

Cerebral cortex and hippocampus of rat were disrupted in a specially designed tissue-press and prepared as a 2 percent suspension in 10 percent buffered Ficoll medium and fractionated by density-gradient centrifugation in the B XIV zonal rotor. The suspension was injected into a buffered 30 percent Ficoll, 58 percent sucrose discontinuous gradient previously loaded in the B XlV zonal rotor spinning at 3500 revolutions per minute. Intact neuronal perikarya were recovered as a discrete band in the dense sucrose zone of the gradient after centrifugation at 35,000 revolutions per minute for 45 minutes.     

Continuous gas chromatography

Continuous gas chromatography has been achieved with a radialflow chromatographic channel free of packing and formed between two closely spaced (50 to 75 microns) disc surfaces (optically flat and solvent-coated) rotating at one-half or one revolution per second. This technique provides high capacity and immediate response (in a fraction of a second). Mixtures of hydrocarbon gases have been separated at flow rates of 6 to 30 cubic centimeters per minute with 100 to 150 cubic centimeters per minute of nitrogen carrier gas in a chromatographic channel only 39 millimeters long.     

Clear air turbulence: an airborne alert system

An infrared radiometer system has been developed that can alert a pilot of an aircraft 2 to 9 minutes in advance of an encounter with clear air turbulence. The time between the warning and the clear air turbulence event varies with the flight altitude of the aircraft. In turbulence-free areas, the incidence of false alarms is found to be less than one in 3.4 hours of flight time compared to less than one per 10 hours of flight time in areas with turbulence.     

Radon-222 in the North Atlantic trade winds: its relationship to dust transport from Africa

The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean. The haze is attributed to dust originating from the arid regions of western Africa. Radon-222 may be useful as a tracer for African air parcels over the equatorial Atlantic.     

Body Temperature of Dermochelys coriacea: Warm Turtle from Cold Water

The deep body temperature of a leatherback turtle, Dermochelys coriacea, taken out of cold water, was 18 degrees C above the water temperature. A large size favoring heat retention from muscular activity is probably responsible for this differential. Cooling rates (k) in water, measured on a second animal, were in the order of 0.001 degrees C per minute per degree of difference between body and ambient temperature.     

Hyperfine zeeman effect atomic absorption spectrometer for mercury

A new type of atomic absorption spectrometer-one that detects trace mercury in host material, based on hyperfine structure lines in a magnetic field-was developed and tested on various substances. This device can detect trace mercury to about 0.04 part per million (40 parts per billion) in about 1 minute. No chemical separation from the host material is necessary.     

Flight at low ambient humidity increases protein catabolism in migratory birds

Although fat is the primary fuel for migratory flight in birds, protein is also used. Catabolism of tissue protein yields five times as much water per kilojoule as fat, and so one proposed function of protein catabolism is to maintain water balance during nonstop flights. To test the protein-for-water hypothesis, we flew Swainson's thrushes (Catharus ustulatus) in a climatic wind tunnel under high- and low-humidity conditions at 18°C for up to 5 hours. Flight under dry conditions increased the rates of lean mass loss and endogenous water production and also increased plasma uric acid concentration. These data demonstrate that atmospheric humidity influences fuel composition in flight and suggest that protein deposition and catabolism during migration are, in part, a metabolic strategy to maintain osmotic homeostasis during flight.     

Nickel-63 in marine and terrestrial biota, soil, and sediment

A previously unreported radionuclide, nickel-63 (half-life, 92 years), produced in the testing of nuclear devices, was measured in biological and environmental samples from areas of the Pacific Ocean and the eastern seaboard of the United States. The concentrations of nickel-63 are low (maximum of 163 disintegrations per minute per gram of dry weight), but this radionuclide may be a useful tracer of oceanic processes because of its long half-life and long residence time in the ocean.     

Room-temperature detection of a single molecule's absorption by photothermal contrast

So far, single-molecule imaging has predominantly relied on fluorescence detection. We imaged single nonfluorescent azo dye molecules in room-temperature glycerol by the refractive effect of the heat that they release in their environment upon intense illumination. This photothermal technique provides contrast for the absorbing objects only, irrespective of scattering by defects or roughness, with a signal-to-noise ratio of ~10 for a single molecule in an integration time of 300 milliseconds. In the absence of oxygen, virtually no bleaching event was observed, even after more than 10 minutes of illumination. In a solution saturated with oxygen, the average bleaching time was of the order of 1 minute. No blinking was observed in the absorption signal. On the basis of bleaching steps, we obtained an average absorption cross section of 4 angstroms(2) for a single chromophore.     

Line-scan hyperspectral imaging system for real-time inspection of poultry carcasses with fecal material and ingesta

In poultry processing plants, fecal material and ingesta are the primary source of carcass contamination with microbial pathogens. The current practice of the poultry inspection in the United States is primarily human visual observations. Since the visual inspection is becoming more challenging in poultry processing plants adopting high-speed lines, a rapid sorting system could significantly improve the detection and monitoring of carcasses with surface fecal material and ingesta. As a result, we developed a prototype line-scan hyperspectral imaging system configured as a real-time multispectral imaging subsystem for online detection of surface fecal material and ingesta. Specifically, we integrated a commercially available off-the-shelf hyperspectral image camera into the system with two line lights and a custom software program for real-time multispectral imaging. The bottleneck of the imaging system was the data acquisition. For that reason, a multithreaded software architecture was designed and implemented not only to meet the application requirements such as speed and detection accuracy, but also to be customizable to different imaging applications such as systemic disease detection in the future. The image acquisition and processing speed tests confirmed the system could operate to scan poultry carcasses in commercial poultry processing plants. The fecal detection algorithm was based on the previous research using different hyperspectral imaging systems. A new carcass detection and image formation algorithm was developed to allow existing image processing and detection algorithms reusable without any modifications. Sixteen chicken carcasses and four different types of fecal and ingesta samples were used in a study to test the imaging system at two different speeds (140 birds per minute and 180 birds per minute) in a pilot-scale poultry processing facility. The study found that the system could grab and process three waveband images of carcasses moving up to 180 birds per minute (a line-scan rate 286 Hz) and detect fecal material and ingesta on their surfaces. The detection accuracy of the system varied between 89% and 98% with minimum false positive errors (less than 1%), depending on tested detection algorithms. Therefore, these findings provide the basis of not only a commercially viable imaging platform for fecal detection but also a single poultry inspection system for multiple tasks such as systemic disease detection and quality sorting.     

乳牛胚胎冷冻保存技术和受胎率的研究

51枚可用胚胎,依次通过含有3.3%,6.7%,10%甘油的抗冻剂处理后,装入26支塑料细管,置于冷冻仪上,以每分钟降低1℃的速率从室温降-6.5℃,平衡5 min 后进行诱发植冰,又平衡5 min,再以每分钟降低0.3℃的速率降至-36℃,平衡10 min 后直接投入-196℃的液氮中保存。先后从液氮中取出16支冷冻保存不同时间(1,8,9,10,28,29,31,32,62天)的冷冻胚胎塑料细管,用30℃温水进行快速解冻,分3步脱除甘油,回收32枚胚胎,其中可用胚胎22枚分别移植给11头受体牛,结果4头妊娠(妊娠率为36.3%)并顺利生下4头发育正常的犊牛。     

Aluminum-26 in pacific sediment: implications

Aluminum-26 has been detected in a sample of sediment from the South Pacific. The disintegration rate of 0.8 disintegration per minute per kilogram of dry sediment is considerably higher than that expected from cosmic-ray spallation of atmospheric argon; it appears to result mainly from accretion of activity induced in interplanetary dust by solar-flare particles. This finding is in keeping with Wasson's published estimates regarding the magnitude of this effect, and confirms the order-of-magnitude correctness of the solar-particle flux and terrestrial accretion rate of interplanetary dust used in that calculation.     

穴盘苗变形滑针式取苗器的研究

半自动移栽机受到人工取苗的限制,单行移栽频率约为45株·min-1,生产率较低.对于穴盘苗移栽,自动取苗代替人工取苗是穴盘苗移栽机械的发展趋势.取苗器是自动取苗系统的末端执行器,其结构及作业条件对穴盘苗取苗成功率的影响直接关系到移栽机械的作业质量.设计了变形滑针式取苗器,运用正交试验和方差分析获得了该取苗器的取苗成功率、影响取苗成功率的显著因素及最佳取苗工作条件.正交试验选取穴盘苗苗龄、苗钵含水量、取苗夹持角度、取苗速度和取苗滑针数这5个因素,结果表明:变形滑针式取苗器平均取苗成功率达83.61%,影响取苗器成功率的显著因素有取苗滑针数和苗龄,取苗夹持角度影响其次,最佳取苗工作条件以25 d穴盘苗苗龄、4根取苗滑针以36°取苗夹持角度为宜.     

AN ADJUSTABLE RESISTANCE WITH LINEAR RESPONSE TO AIR FLOW FOR RESPIRATION EXPERIMENTS

A. simple easily adjustable linear response resistance apparatus is described. The resistance unit contains a glass filter cloth, the effective area of which is adjusted by a mercury column. The resistance of the unit can be adjusted from 0.1 to 1.0 millimeters of water per liter of air flow per minute. The resistance can be easily increased or decreased during the progress of an experiment. The mercury hazard during inspiration was evaluated and not found significant for experiments of one hour.