A simple and low‐cost method to estimate spatial positions of shorebirds: the Telescope‐Mounted Angulator

ABSTRACT Estimating the spatial position of birds in open habitats like intertidal mudflats is important for many studies, for example, detailed density estimates or linking predation pressure to resource availability. To date, several methods have been used to estimate the positions of birds, including density counts in predetermined plots, range finders, photography, and tracking individuals tagged with GPS‐equipped transmitters, and each method has advantages and shortcomings. Counts in premarked plots are possible over relatively long distances, but small‐scale information is lost due to within‐plot averaging. Other methods accurately determine the position of individuals, but can only be used at relatively short distances or involve capturing birds. We describe a simple and low‐cost method to estimate the spatial position of individual birds in open habitats using a telescope‐mounted instrument that measures the scope's viewing angle. Using this Telescope‐Mounted Angulator (TMA), the distance to focal birds can be calculated by simple trigonometry, requiring only the viewing angle and mounting height of the telescope. Laboratory tests revealed that the TMA was most accurate when calibrated for individual observers. Field experiments performed on a 4‐m high observation platform showed that the TMA can estimate the position of shorebirds with an accuracy of 18 to 36 m up to a distance of 500 m. By also including the direction, determined with a compass, the spatial position of birds can be reliably estimated. The TMA can be a valuable tool for estimating the spatial position of animals in various flat landscapes, providing detailed measurements in a relatively short period of time.     

Selective reduction and alkylation of the COOH-terminal disulfide bridge in bovine growth hormone.

Conditions leading to the cleavage of both disulfide bridges in human growth hormone caused the reduction of only one disulfide bond in bovine growth hormone. Partially reduced and alkylated derivatives of bovine growth hormone were prepared and characterized. It was shown that the reduction and alkylation modified the COOH-terminal disulfide bond, however, this modification does not result in the dissociation of the dimeric form of bovine growth hormone or cause a significant loss of growth-promoting activity.     

Household salt for retrospective dose assessments using OSL: signal integrity and its dependence on containment,sample collection,and signal readout

The aim of this work was to determine how a latent optically stimulated luminescence (OSL) signal in irradiated household salt is preserved under various ambient conditions, from the time of exposure to the time of signal readout. The following parameters were examined: optical fading in fluorescent light and under darkroom conditions (red light), thermal stability of the OSL signal during storage in a light-tight container, optical fading in representative container types, and sensitization effects of the OSL signal in exposed household salt. Furthermore, the influence of grain mixing within the saltshaker or salt container was studied by determining the dose gradient within typical salt packages. Finally, the signal integrity of salt irradiated under field conditions in a village in Belarus contaminated by Chernobyl fallout was investigated. The results show that the OSL signal in household salt is preserved in large cardboard box containers, but not in white plastic salt containers or in small portion bags used in, e.g., fast food restaurants. Furthermore, the continuous wave blue OSL signal in household salt does not fade significantly during storage up to 140 days. On the contrary, the signal appears to slowly increase during storage (“inverse fading”). Field tests of two different salt containers (with and without black tape to block light) located in Belarussian households confirmed that the signal is preserved in white plastic salt containers when they are covered with extra light-shielding material.     

Influence of maternal stress on offspring sexual behaviour

During the last trimester of gestation, pregnant rats were exposed to crowded living conditions, or to immobilization combined with intense illumination. In adulthood, male offspring of mothers exposed to either condition of stress showed increased readiness to display feminine sexual behaviour (lordosis) while no deficits were observed in their masculine sexual behaviour. It was concluded that prenatal stress adversely affects sexual differentiation by causing a feminization but not a demasculinization of male offspring.     

Effect of castration on hypothalamic testosterone metabolism in the male rat

In vitro studies were performed of hypothalamic testosterone (T) metabolism 30 days after castration of adult male rats. No changes were seen in T conversion into dihydrotesterone and estrogens in the castrated rats. Plasma T levels were decreased while plasma estradiol concentrations did not differ from those of intact controls. It was suggested that the hypothalamic T metabolism probably is not androgen dependent.     

Interorgan movements of amino acid in the pig: effects of dietary fibres

Summary Six non-anaesthetized Large White pigs (mean body weight 59 ± 1.7 kg) were fitted with permanent catheters in the portal vein, the brachiocephalic artery and the right hepatic vein as well as with electromagnetic flow probes around the portal vein and around the hepatic artery. The animals were given a basal none-fibre diet (diet A) alone or together with 6% guar gum (diet B) or 15% purified cellulose (diet C). The diets were given for one week and according to a replicated 3 × 3 latin square design. On the last day of each such adaptation period test meals of 800 g were given prior to blood samplings. These samplings were continued for 8 h. Guar gum strongly reduced the amino acids (aa) and urea absorption as well as the hepatic production of urea. The aa profile of the absorbed mixture was not strongly modified by guar gum ingestion as well as the profile of the hepatic aa uptake. Cellulose at the consumed level had very few effects on the considered parameters.It is suggested that the modulation of intestinal mechanisms by guar gum was sufficient to mediate the latter internal metabolic effects.     

Cell cycle-dependent localization of monoclonal antibodies raised against isolated Dictyostelium centrosomes.

The ultrastructure of the Dictyostelium centrosome is markedly different from that of the well known yeast spindle pole body and vertebrate centriole-containing centrosome. It consists of a box-shaped, layered core structure surrounded by a corona with dense nodules embedded in an amorphous matrix. For further structural and biochemical analyses of this type of centrosome we used highly enriched isolated Dictyostelium centrosomes as an antigen to raise 14 new centrosomal monoclonal antibodies. Immunofluorescence microscopy and Western blot analysis revealed that at least 10 of them were directed against different antigens. Immunofluorescence microscopy also showed that the monoclonal antibodies fell into three different groups: A) antibodies localizing to the centrosome during the entire cell cycle; B) antibodies staining the centrosome mainly during mitosis; and C) antibodies labeling centrosome associated structures. All antibodies, except one, exhibited a cell cycle-dependent staining pattern underscoring the highly dynamic properties of the Dictyostelium centrosome.     

Condylomata acuminata and risk of cancer: an epidemiological study.

OBJECTIVE--To determine whether patients with condylomata acuminata have an increased risk of developing cancer. DESIGN--Prospective cohort study on patients diagnosed as having condylomata acuminata. The number of malignant tumours in the cohort was compared with national incidences obtained from the Swedish Cancer Registry. SETTING--Dermatology department of the Karolinska Hospital, Stockholm, Sweden. SUBJECTS--3260 patients (2549 males and 711 females, median (range) age 23 (1-80) years) seen during 1969-84, with a mean follow up of 7.8 years. MAIN OUTCOME MEASURES--Number of malignant tumours observed in the cohort during the study period and expected number from national incidence. RESULTS--There were 27 malignancies in the study group. There was no significant increase genital cancer in females compared with the national incidence. Only one patient had invasive cervical cancer (relative risk = 1.8; 95% confidence interval 0 to 10.1). Seventeen women had cervical carcinoma in situ (1.5; 0.9 to 2.5) compared with an expected number of 11.5; this increase was not significant. For males 22 cancers were observed at all sites (1.6; 1.0 to 2.5). The number of genitourinary cancers observed in males was almost three times higher than expected (2.6; 1.2 to 5.0). CONCLUSION--The results indicate that the risk of developing cervical carcinoma in situ or invasive cervical cancer after a genital human papillomavirus infection is less than previously thought. The implications of increase in the genitourinary malignancies in males are uncertain.