Scent-Marking in the Eurasian Beaver (Castor fiber) as a Means of Territory Defense

Beaver (Castor spp.) normally scent-mark by depositing castoreum and/or anal gland secretion on scent mounds close to the water's edge. The aim of this study was to investigate the hypothesis that the Eurasian beaver (C. fiber) scent-marks as a means of territory defense. Scent-marking behavior was studied during an entire year (April 1, 1995–March 31, 1996) in seven adjacent territories along 9.2 km of the B River in Telemark County, Norway. The number and location of fresh scent marks were recorded biweekly. The main results showed that: (1) the number of scent marks in territories was significantly higher in spring, when dispersal of subadults normally occurs than during the rest of the year; (2) the number of scent marks was clumped near territorial borders; and (3) the number of scent marks was significantly greater upstream than downstream of the lodge.     

Sexual Dimorphism in Territorial Scent Marking by Adult Eurasian Beavers (Castor fiber)

Mammalian scent marking is often associated with territorial defense. However, males and females may demonstrate different activity patterns and play different roles. Female mammals nurture the young during lactation, while males purportedly perform other tasks more frequently, such as territorial maintenance and defense. This paper investigates the contribution made by mated pairs of adult males and females to territorial scent-marking in the obligate monogamous Eurasian beavers (Castor fiber). We hypothesized that both sexes should show territorial behavior, and predicted that they deposit a higher proportion of scent marks at borders. We also hypothesized that a sexual dimorphism exists due to reproductive constraints on the females, and predicted that males should invest significantly more in scent-marking behavior than females during summer. We obtained behavioral data by radio tracking six mated pairs of Eurasian beavers during spring and summer 2000–2001 on two rivers in southeastern Norway. Our results showed that both males and females clustered their scent marks near territorial borders, but males deposited a larger number of scent marks than females and spent more time at borders. Males were also found to have a higher scent marking rate and scent marks per night than females during summer, but not during spring. Overall, scent marks per night were higher in males than females. We conclude that both males and females Eurasian beavers carry out territorial behavior by scent marking, but males carry a larger part of the territorial defense during summer when females lactate. Our results are discussed in the light of the codefense hypothesis.     

Beaver (Castor canadensis) responses to major phenolic and neutral compounds in castoreum

North American beaver (Castor canadensis) mark their territories with castoreum, a chemically complex secretion from their castor sacs. The phenolic and neutral fractions of castoreum have been shown to elicit specific behavioral responses from beavers in a field setting. Our objective was to identify compounds/mixtures that evoked responses similar to those stimulated by castoreum. We assayed recently identified phenolic compounds, some phenolics that had been determined to be biologically active in previous studies, the neutral compound borneol, and combinations of phenolic compounds, neutral compounds, and the two combined. Biological activity was measured by the elicitation and extent of specific responses and their strength (duration, frequency, and proportion of beavers responding). Generally, single compounds stimulated fewer responses than mixtures. A 26-compound mixture of phenolic and neutral compounds elicited responses in a similar proportion of trials as castoreum. However, responses to castoreum were stronger than to any synthetic sample. Further investigation of different measures of response, namely, elicitation, completeness, and strength, are deemed necessary to fully decipher the design of social odors.     

Odorant Source Used in Eurasian Beaver Territory Marking

Mammals use urine, feces, or the secretion of specialized skin glands to mark their territories. These sources can carry different information and, thus, have different functions. Presently it is not known if beavers (Castor spp.) deposit castoreum (primarily a mixture of secondary metabolites from urine) from the castor sacs and secretion from the anal glands (AGS) together or alone when scent marking their territories. We hypothesized that castoreum would be the main scent signal used in the defense of beaver territories during winter and predicted that castoreum would be deposited more often than AGS. A total of 96 scent marks on snow were collected from January 1 to March 31, 1997–1999 in the Bø River, Telemark County, Norway. In order to obtain control material, we chemically analyzed AGS and castoreum from 60 dead beavers collected during January–May 1997–1999. We compared the compounds found in the dead beavers with compounds found in the scent marks on snow. Samples were analyzed by using gas chromatography–mass spectrometry (GC-MS). All 96 scent marks contained compounds from castoreum, whereas compounds from AGS were found in only four scent marks. This suggests that beavers do not specifically deposit AGS on scent mounds as they do with castoreum and that the AGS compounds we found probably were remnants of AGS from the feet or fur following pelt lubrication or coprophagy behavior. We conclude that castoreum is the main scent signal used in the defense of beaver territories during winter.     

Manipulating Beaver (Castor canadensis) Feeding Responses to Invasive Tamarisk (Tamarix spp.)

To evaluate methods for promoting consumption of tamarisk plants by beavers (Castor canadensis), we determined the feeding responses by captive beavers to diets that contained tannins and sodium chloride (hereafter referred to as tamarisk diet). In two-choice tests, beavers consumed equivalent quantities of tamarisk diet and control diet. Treatment with polyethylene glycol and fructose did not increase beaver preferences for the tamarisk diet. When offered the choice of control diet and casein hydrolysate-treated control diet, beavers strongly avoided the latter, showing feeding deterring activity of casein hydrolysate. However, when tamarisk diet was the alternative to the deterrent treatment, beavers consumed similar quantities of the two diets. Finally, beaver foraging preferences for actual plant cuttings were assessed. Casein hydrolysate application to cuttings of black poplar (Populus nigra) and Scouler's willow (Salix scouleriana) reduced browsing of these highly preferred species and promoted a marked increase in browsing of tamarisk (Tamarix ramosissima). These results suggest that casein hydrolysate treatment of desirable riparian plant species such as Salix and Populus may promote beaver foraging of invasive tamarisk.     

Social Signals Involved in Scent-Marking Behavior by Cheek-Rubbing in Alpine Marmots (Marmota marmota)

The Alpine marmot Marmota marmota is a territorial rodent. Resident adults regularly scent-mark their territory by cheek-rubbing, mainly on burrow entrances and along boundaries. The purpose of this three part study was to gain further insight into this scent-marking behavior by: (1) observing the response of free-ranging marmots to foreign scent marks, (2) confirming the glandular source of the marking substance by histologic examination of the temporal gland, and (3) identifying biologically active chemical fractions of the marking substance. To allow field tests, we developed a device consisting of a glass tube placed upside down over a stake. Two devices were simultaneously placed at one burrow entrance. On one device, a clean tube was used and, on the other, a tube alternatively coated with either whole natural scent-marking substances or various fractions obtained by solvent extraction or chromatographic separation from whole scent-marking substances. Subsequent observations showed a significant difference in the duration of nose contact and number of cheek-rubbing movements. Resident adult marmots sniffed and marked tubes bearing alien marks significantly more than clean control tubes. Similar differences in behavior were observed with ethanol extracts of whole scent-marking substances. Extracts obtained with pentane and dichloromethane showed no bioactivity, suggesting that highly polar compounds are the active substances in the Alpine marmot. The temporal gland is an exocrine gland located on each side of the head with numerous pores opening at the surface of the skin in the cheek area. GC-MS analysis of individually collected samples from these glands showed that over 30 compounds were consistently present. Seven of these compounds were identified. Two fractions were obtained and used together and separately in field tests. Fraction 1 was composed mainly of short-chain alcohols and alkanes, and fraction 2 had a more acid and ester composition. The fact that these two fractions were active together but not separately strongly suggests that the active territorial signal results from a synergistic interaction between several compounds.     

Factors Affecting the Compaction and Densification Behavior of Ti(C,N)‐Based Cermet Powders

In this study, the effects of the major factors on compaction and densification behavior are investigated for Ti(C, N)‐based cermet powders. The relative density equation for green compact of composite powders is modified to predict the green density of Ti(C, N)‐based cermet powders prepared under different degrees of pressing pressures, and the theoretical values are found to be in good agreement with experimental results. It has been found that the composite powders with micron‐sized particles have a better compatibility than those with nano‐sized particles by analyzing the effects of the particle size and purity on the starting mono‐powders. It has also been found that the volume shrinkage and porosity of the former are lower than that of the latter. In addition, it shows that high oxygen content has a negative impact on both the compatibility of composite powders and the uniformity of pore size distribution of sintered cermets. It has also been discussed in this study how the pressing parameters such as pressing pressure, pressing temperature, and dwell time influence the resulting cermets. The results indicate that a better compatibity is reached at a pressing rate of 100 mm/min or a pressing temperature of 100°C.     

聚乙烯醇缩醛树脂中残留甲醛含量的影响因素

以尿素为甲醛捕捉剂,探讨了缩醛反应时间、反应温度、甲醛和聚乙烯醇的配比、盐酸、尿素、氢氧化钠等对聚乙烯醇缩甲醛溶液中残留甲醛含量的影响。结果表明,增加缩醛反应时间,利于降低产物游离甲醛含量。缩醛反应温度太低,产品中残留甲醛含量高。当反应温度由75℃增至88℃时,残留甲醛含量呈先快后慢的下降趋势变化。随投料中甲醛用量的提高,产物游离甲醛含量直线上升。当m（盐酸）：m（PVA）由0．12增至0．29时,甲醛残余量则由0．247％降至0．216％。增加尿素用量,甲醛残余量先快速下降,然后缓慢下降。增加氢氧化钠用量,残留甲醛含量先缓慢增加,后快速增加。     

影响天然橡胶中挥发份的因素分析

介绍影响天然橡胶中挥发份的各种因素,证明了挥发份的测定必须在标准条件下进行所得的数据才比较准确可靠。     

Red maple (Acer rubrum) inhibits feeding by beaver (Castor canadensis)

At many beaver (Castor canadensis) sites at Allegany State Park in New York State, red maple (Acer rubrum) is the only or one of the few tree species left standing at the ponds' edges. The relative palatability of red maple (RM) was studied in three ways. (1) At seven beaver sites, the available and utilized trees were recorded and an electivity index (E) computed. Of 15 tree species, RM ranked second or fourth lowest. (2) In experiment I, RM, sugar maple (A. saccharum, SM), and quaking aspen (Populus tremuloides) logs were presented cafeteria style at 10 colonies. RM was the least preferred. (3) Bark of RM was extracted with solvents. Aspen logs were painted (experiment II) or soaked (experiment III) with this RM extract and presented to beaver cafeteria-style, along with aspen and RM controls. This treatment rendered aspen logs less palatable, indicating that a chemical factor had been transferred.     

The social role of scent marking in beaver (Castor Canadensis)

Beaver colonies with close neighbors constructed more scent mounds than did isolated colonies, and the number of scent mounds at each active lodge is correlated with the distance to the nearest occupied lodge. The scent mounds were typically located at trails, also on lodges and dams. The beaver rebuilt experimentally removed scent mounds. Experimentally scent-marked unoccupied lodges were less often visited or inhabited than unscented control lodges. Resident beaver responded to artificial scent marks near their lodges with aggressive behavior and increased activity. We conclude that scent mounds serve in delineating family territories and are effective in deterring transient beaver from utilizing existing but uninhabited lodges.     

Patterns of scent-mounding in a population of beaver (Castor canadensis)

The frequency and pattern of distribution of scent-mound construction were studied in a population of beaver in southeast Ohio from 1975 through 1977. The study addressed the questions of whether or not the frequency of scent-mound construction varied with season, site, year, and degree of contact with other family groups, and whether the pattern of scent-mounding activity was parsimonious with the idea of territorial marking. The number of scent-mounds constructed was determined weekly for each site throughout the ice-free season. Scent-mounding activity was highest in spring and declined and remained low during summer and fall. Significant differences were found amoung sites and over years. Contact with other resident family groups altered both frequency and pattern of scent-mound construction. Scent-mounds did not conform to a scent-fence model. The most parsimonious interpretation of function of odor cues deposited on scent-mounds is the effect on the motivational state of residents and nonresidents, increasing the confidence and reducing anxiety in residents smelling their own scent-mound and decreasing the confidence and increasing the readiness to flee in trespassers encountering a strange scent-mound.     

Factors Affecting on the Sorption/Desorption of Eu (III) using Activated Carbon

Abstract

The sorption and desorption of Eu (III) on H‐APC activated carbon using a batch technique has been studied as a function of carbon type, shaking time, initial pH solution, temperature, particle size of carbon, and concentration of the adsorbent and the adsorbate. The influence of different anions and cations on adsorption has been examined. The experimental data have been analyzed by Langmuir, Freundlich, and Temkin sorption isotherm models and the adsorption data for Eu (III) onto activated carbon were better correlated to the Temkin isotherm and the maximum absorption capacities obtained was 46.5 mg g^?1. Anions of phosphate, carbonate, oxalate, and acetate were found to increase the adsorption of Eu (III), whereas nitrate, chloride and all studied cations, potassium, sodium, calcium, magnesium, and aluminum have a negative effect on the adsorption capacity. More than 99% europium adsorbed on H‐APC eluted with 0.5 M HCl solution. The activated carbon prepared from apricot stone using 70% H₃PO₄ could be considered as an adsorbent that has a commercial potential for Eu (III) treatment.     

Study of Factors Affecting the Color Fastness of High Depth fiber Dyed in Silicon Non-aqueous Medium Dyeing System

Silicon - Multiple washing and soaping are very important to remove floating color on the surface of indigo denim fabric in the traditional water bath. In indigo/silicon non-aqueous dyeing system,...     

影响装置氨产量的因素探讨

依托合成氨现有装置,针对实现继续深挖氨产能力的目标,深入分析影响氨产量的各项因素。     

高光泽PS的影响因素

研究了不同的树脂和助剂在高抗冲聚苯乙烯（HIPS）和通用级聚苯乙烯（GPPS）中对光泽度的影响。主要比较了GPPS、低分子量SBS和液体聚丁二烯对高光HIPS光泽度的影响,另外还研究了K树脂、低分子量SBS和液体聚丁二烯对GPPS光泽度的影响。结果表明通过液体聚丁二烯与K树脂复配可以提高GPPS的冲击性能。     

影响炉内脱硫的因素

二氧化硫是大气污染的主要来源,在燃煤锅炉的炉内加石灰石脱硫是其中方法之一.阐述了影响锅炉炉内脱硫的各种因素.     

Responses of beaver (Castor canadensis Kuhl) to predator chemicals

Free-ranging beaver (Castor canadensis) in two different beaver populations in New York State were exposed to predator chemicals to test feeding inhibition. Solvent extracts of feces were applied to stem sections of aspen, the preferred food tree of beavers, permitting smelling and tasting the samples. Predator odors were from wolf (Canis lupus), coyote (Canis latrans), dog (Canis familiaris), black bear (Ursus americanus), river otter (Lutra canadensis), lynx (Lynx canadensis), and African lion (Panthera leo). The experiment was repeated. The predator odors reduced feeding compared to untreated or solvent-treated controls. One population consumed 17.0% of the samples with predator odor and 27.0% of the controls in summer, and 48.4% and 60.0%, respectively, in autumn. The other population accepted 3.15% of the predator odor samples and 11.05% of the controls in summer. Coyote, lynx, and river otter odors had the strongest effects. Diesel oil and bitter-tasting neem extract had weaker effects. Predator odors are promising as feeding repellents for beaver.     

影响磷石膏中残磷含量的主要因素分析

实现磷石膏的资源化，已经成为贵州省肥、磷化工企业可持续发展的重要影响因素；磷石膏中残磷的高含量不仅降低了磷酸的萃取率，同时影响磷石膏的资源化利用；分析了影响磷石膏化学成分的各种主要因素，并从磷石膏资源化的角度，讨论了磷石膏中的残磷及其影响因素；磷石膏成分随这些影响因素的不同而变化。     

低黏度氢化蓖麻油聚氧乙烯(40)醚的合成

以氢化蓖麻油和环氧乙烷为原料,三氟化硼乙醚作催化剂,合成了氢化蓖麻油聚氧乙烯(40)醚。产物为极淡黄色,常温下为透明液体,羟值为70~80 mg KOH/g,皂化值为60~70 mg KOH/g,黏度为1 500~2 000 mPa.s。对影响目标产物黏度、色泽、外观、羟值和皂化值的主要因素进行了优化,得到了适宜的反应条件:w(三氟化硼)=0.8%~1.3%,反应温度100~120℃。用500 L反应釜进行扩试生产,得到的产品色泽为极淡黄色,常温下为透明液体,羟值为70.3 mg KOH/g,皂化值为63.2 mg KOH/g,黏度为1 620 mPa.s。