The poetry of science

During the past year, I have taken part in an experiment in which I have been the experimental animal. I was awarded a fellowship that gave me the opportunity to take a sabbatical from science and spend a year in the School of Literature and Creative Writing at the University of East Anglia. The School of Literature and Creative Writing is internationally renowned, and past students include household names such as Ian McEwan, Kazuo Ishiguro, Trezza Azzopardi and Tracy Chevalier. I have a keen interest in creative writing and had written a few short stories. This was a formidable but thrilling challenge. During my adventure, I realized that, in many ways, I was coming home.     

Marginal bone loss around axial and straight implants supported with prefabricated SFI-Bar with mandibular overdentures

To assess the role of prefabricated SFI-Bar in peri-implant bone loss around immediately axially loaded and straight implants. This study comprised of 40 complete denture wearer patients who received two axially parallel implants connected by SFI-Bars in group I and two 15° mesially tilted implants connected by SFI-Bars in group II. Peri- implant bone loss (PiBL) was measured at 1 year, 2 years and 3 years. The mean PiBL at 1 year in group I was 0.21 mm and I group II was 0.22, at 2 years in group I was 0.26 mm and in group II was 0.23 mm and at 3 years, in group I was 0.29 mm and in group II was 0.34 mm. The difference was significant at 3 years (P< 0.05). The mean mesial PIBL at 1 year in group I was 0.18 mm, in group II was 0.20 mm, at 2 years in group I was 0.19 mm and in group II was 0.07 mm and at 3 years, in group I was 0.25 mm and in group II was 0.29 mm. The difference found to be significant in each time duration in both groups (P< 0.05).The mean distal PIBL at 1 year in group I was 0.23 mm, in group II was 0.22 mm, at 2 years in group I was 0.33 mm and in group II was 0.39 mm and at 3 years, in group I was 0.34 mm and in group II was 0.39 mm. The difference found to be significant at 2 and 3 years in both groups (P< 0.05). Authors found that mandibular overdentures retained with Prefabricated SFI-Bar with axial and straight inserted implants may be useful in patients with reduced bone height.     

Differences in Borrelia infections in adult Ixodes persulcatus and Ixodes ricinus ticks (Acari: Ixodidae) in populations of north-western Russia

Dark-field microscopy was used to determine the number of Borrelia spirochetes in 630 standard preparations obtained from adult ixodid ticks (344 Ixodes persulcatus and 286 I. ricinus) collected in 1989-92 in the Leningrad region of Russia. The average numbers of Borrelia in I. persulcatus and I. ricinus preparations were 34.7 and 23.3 per 100 microscopic fields, respectively. The maximal individual values registered each year for ticks of both species were several hundred times greater than the minimal values. Ticks carrying relatively small numbers of Borrelia generally predominated. Proportions of more heavily infected ticks varied considerably from year to year. These parameters were significantly higher in foci with predominance of I. persulcatus ticks. As a consequence, risk to acquire Lyme borreliosis in such foci is considered greater than in foci where I. ricinus predominates.     

Fruit Production and Seed Predation in Two Miombo Woodland Trees in Zambia

During a six year period (1990–1995) fruiting frequency among marked trees and seed production and predispersal predation by beetle larvae of lsoberlinia angolensis and Julbernardia globiflora of the Leguminosae family and Caesalpinoideae subfamily were studied at two dry miombo woodland sites in central Zambia. Fruit production varied from year to year and was not related to annual rainfall. On average I. angolensis trees fruited once every two years while J. globiflora trees fruited once every two and one-half years. Number of fruits per tree was correlated with tree size for both species. In a peak year fruit biomass represented two to four percent of total above ground biomass but for J. globiflora about 5.5 and 4.5 percent of nitrogen and potassium, respectively, were in fruits compared to 0.6 and 1.8 percent for I. angolensis. The lower fruiting frequency in J. globifora was probably related to the depletion of N reserves during a fruiting year which required a longer replenishment period than in I. angolensis. Predispersal seed predation was low for J. globiflora (10%) and very high in I. angolensis (65–85%) and for the latter species predation rate increased from August to November 1991 and significant variations were observed among years and pod types. Seed predation rate was lowest in a peak fruiting year and this observation provides support for the satiation hypothesis. The results of the study also suggest that I. angolensis and J. globiflora may have different regeneration strategies although reproductive allocation in both species was within the range reported for other iteroparous plants.     

Are northern mockingbirds classic open-ended song learners?

The northern mockingbird (Mimus polyglottos, Linnaeus) is considered a classic example of a species in which individuals learn songs throughout adulthood, but this assumption has not been tested rigorously. To assess whether mockingbirds should be categorized as open-ended learners, I conducted a longitudinal study and a field-based song-tutoring experiment. I recorded songs from 15 free-living, banded, adult males in an earlier year and a later year, and I classified 400 mimetic songs per year per individual, based on the species and vocalization type mimicked. For two of these “mimetic types,” I further classified all the song types of all individuals in their early and later samples. The number of song types increased significantly across years for both mimetic types, and the average number of observed mimetic types per individual was 46.4 and 47.7 in the early and late samples (p = .055). I found no evidence adults learned any tutor stimuli after six months of tutoring, but examples from the scientific literature suggest the tutoring regime might not have been adequate to pass the motivational threshold required for learning. I conclude that mockingbirds probably are open-ended learners, but that future research is needed to verify experimentally that adults can indeed imitate novel song types.     

Testing mate choice and overdominance at MH in natural families of Atlantic salmon Salmo salar

This study aimed to test mate choice and selection during early life stages on major histocompatibility (MH) genotype in natural families of Atlantic salmon Salmo salar spawners and juveniles, using nine microsatellites to reconstruct families, one microsatellite linked to an MH class I gene and one minisatellite linked to an MH class II gene. MH‐based mate choice was only detected for the class I locus on the first year, with lower expected heterozygosity in the offspring of actually mated pairs than predicted under random mating. The genotype frequencies of MH‐linked loci observed in the juveniles were compared with frequencies expected from Mendelian inheritance of parental alleles to detect selection during early life stages. No selection was detected on the locus linked to class I gene. For the locus linked to class II gene, observed heterozygosity was higher than expected in the first year and lower in the second year, suggesting overdominance and underdominance, respectively. Within family, juveniles' body size was linked to heterozygosity at the same locus, with longer heterozygotes in the first year and longer homozygotes in the second year. Selection therefore seems to differ from one locus to the other and from year to year.     

Year-class coexistence in biennial plants

I extend the well known and biologically well motivated Skellam model of plant population dynamics to biennial plants. The model has two attractors: either one year class competitively excludes the other, resulting in 2-cycles with only vegetative vs only flowering plants in alternating years, or the two year classes coexist at an interior equilibrium. Contrary to earlier models, these two attractors can exist also simultaneously. I investigate the robustness of the model by including delayed flowering, a common phenomenon in plants, and provide a full numerical bifurcation analysis of the generalized model. High fecundity implies strong competition within year classes and promotes coexistence, whereas high survival results in strong competition between year classes and promotes competitive exclusion. Delayed flowering tends to stabilize the interior equilibrium, but (unlike in density-independent matrix models) the population cycles are robust with respect to some delay in flowering.     

Development of ixodid ticks in the northern limits of their geographic range in Amur Province

In the northern part of the Amur district the life cycle of I. persulcatus and H. concinna lasts three, four and five years while that of D. silvarum--one year. The distribution of I. persulcatus and H. concinna further to the north is limited by an unsufficient heat for the development of eggs while for D. silvarum heat is not enough to complete its life cycle within a year.     

Thyrotropin receptor antibody activities significantly correlate with the outcome of radioiodine (131I) therapy for hyperthyroid Graves' disease.

The outcome of 131I therapy for 109 patients with Graves' disease was analysed according to pretreatment laboratory data including thyrotropin receptor antibody (TRAb) activities. Forty-five percent of patients became euthyroid, and 13% of patients became hypothyroid within one year after 131I therapy. Forty-two percent of patients remained hyperthyroid one year after 131I therapy. Pretreatment values for serum T4, T3, and the estimated weight of the thyroid were significantly higher in the hyperthyroid group. The mean for the TRAb index of the hyperthyroid group was significantly higher than that of the euthyroid group. Life table analysis revealed a significant effect of the TRAb index on the rate of hyperthyroidism after 3 months or later. These results appear to suggest that the TRAb index is one of the factors which influence the outcome of 131I therapy for Graves' disease.     

Changes in the Glucocorticoid Function of Adrenals in First Year Schoolboys during Adaptation to the Beginning of School Studies and during the School Year

The glucocorticoid function of adrenals was studied in 23 first-year schoolboys that were subdivided into health groups I and II. The character and time organization of the infradian dynamics of the cortisol were studied during the period of acute adaptation to the beginning of schooling and throughout the school year. The schoolboys of health group II were different from those of group I by both the higher level of the week mesor and its dynamics during the entire school year. By the end of the first half of the year, the structure of cortisol infradian rhythms was changed in the first-year schoolboys of group II: the slow rhythms of cortisol secretion with the period of five to seven days became predominant, and the fact that the absolute values of their amplitudes were significantly increased suggested a tension in the functions of the adrenal cortex.     

Protist 2000

As Protist enters the year 2000, the third year of its existence, it may be appropriate to briefly evaluate the past and look forward to what readers and authors of the journal can expect in the near future.It is fair to say that editing the journal over the past two years has been an enlightening experience, more work but also more fun than I anticipated. Whatever has been achieved, it would not have been possible without the tremendous support I received from my co-editors, the publisher and his staff and my secretarial office. Of no less importance has been the constructive criticism of fellow protistologists, readers and authors alike.I wish to thank Paul Falkowski, Rick A Firtel, and Frances D Gillin who have resigned from the Editorial Board for all their help in getting the journal started, and I welcome Randall S Alberte, Donald M Anderson, Richard Kessin and Peter Upcroft as new Board members.Protist has rapidly become one of the premium international journals for protist research, its impact factor, to be issued later this year will testify to this. The journal is covered by MEDLINE and a full text (PDF) online version is now available free of charge through the year 2000 on the publisher's Web site (http://www.urbanfischer.de/journals/protist).Protist will continue to publish high quality original work in all areas of protist research using the highest quality reproduction methods available today. In addition the highly successful “Protist News” and “From the Archives” sections for which authors are usually invited, will remain regular features of the journal.Protist in the year 2000 opens a new chapter of protist research. I invite you to join in this as a reader and a contributor.     

Reproductive cycle and sexual maturity of the anglerfish Lophiomus setigerus in the East China Sea with a note on specialized spermatogenesis

The reproductive cycle and sexual maturity of the anglerfish Lophiomus setigerus were examined. Spermatids were released from the germinal cysts into the lumina of the seminal lobules, and both spermatids and spermatozoa were present in the lumina of the seminal lobules and sperm ducts. Spermatogenesis and vitellogenesis occurred throughout most of the year. The testes of males were full of spermatozoa throughout the year, with spawning from May to November. Males and females reached sexual maturity at a mean total length and age of 178 mm, 3.3 years and 303 mm, 6.1 years, respectively. There were clear seasonal cycles in the gonadosomatic index (I_G) and hepatosomatic index ( I _H) in females. The mean I_G of females increased rapidly with ovarian development while the mean I _H decreased from the middle of vitellogenesis to final maturation. Mean values of I _G and I _H in males increased with testicular development.     

Studies on Dawsonia superba Grev. II. Growth rate

Abstract

The shoot growth of plants in two clumps of Dawsonia superba was monitored in conjunction with temperature, humidity and throughfall for one year. Growth was found in both cases to be strongly positively correlated with mean air temperature. In one clump a negative correlation with mean atmospheric water deficit was also found. Growth rates as high as 48 mm per year were obtained for the fastest growing plants. Average growth rates were 24 mm per year for Clump I and 15 mm per year for Clump 2.     

Chemical Properties of the Diets of Two Lemur Species in Southwestern Madagascar

Seasonal dietary variations demonstrate the importance of certain plant parts during the year. A parallel analysis of their nutritional constituents provides further information on underlying patterns of consumption of the plant parts and the relative importance of key nutrients. I studied the diets of Lemur catta (ring-tailed lemurs) and Propithecus verreauxi verreauxi (sifakas), for 9 mo over a 13-mo period in the highly seasonal tropical dry forest site of Beza Mahafaly in southwestern Madagascar. I tested dietary plant parts for nutrients—protein, free amino acids, and sugars—and for 2 potential deterrents, phenolics and tannins, using plant extracts prepared in the field. I compared consumption of nutrients and secondary compounds throughout the year and between seasons. Nutrients are balanced throughout the year. The 2 lemur species do not appear nutrient-starved in either season, though actual quantities of nutrients and contributing food parts differ for each species. Lemur catta consumes high levels of sugar throughout the year, whereas Propithecus takes in higher levels of protein. The effects of phenolics and tannins are quantitative, and they appear to deter consumption of plant parts only past a certain threshold. Sifakas consume them in greater quantities than those of ring-tailed lemurs, which appear more sensitive to their effects. Sifakas may have a higher tolerance for secondary plant metabolites, which is consistent with reports for other folivores. The overall stability of nutrients throughout the year indicates no lean period that coincides with the decline in food abundance during the dry season, though actual caloric intake probably decreases.     

Large prey for small cubs - on crucial resources of a boreal red fox population

Many studies of red fox Vulpes vulpes diet have indicated a higher frequency of large prey in the diet of cubs at dens in relation to that of adults From time to time this finding has been questioned as an artifact due to the different types of sampling In this paper I suggest that the observations were correct and reflected optimal behaviour of a central place forager I compared the diet of foxes by analyses of 112 cub scats collected at breeding dens and 168 adult scats collected during the same periods The study was performed in a boreal environment, characterised by cyclically fluctuating vole populations According to theory the diets should converge when voles become plentiful During a year of low, but increasing, vole densities, a significantly higher proportion of large prey was found in the sample from cubs than from adults This was not the case during the peak and the decline year, when the presumably easily available voles appeared frequently in the scats of both cubs and adults I argue that the availability of large prey during the first year of increasing vole densities might determine territory sue and hence also average population density of foxes throughout the whole cycle in boreal foxes     

The teaching of physiological disciplines in the 3rd Faculty of Medicine,Charles University,Prague, Czech Republic

The physiological disciplines are being taught from the 1st year of medical study up to the end of the 4th year, it means 8 semesters altogether. It is necessary to explain the curriculum of the 3rd Faculty of Medicine, Charles University in Prague. This Faculty has had a new curriculum since 1997, so the first students, who had been taught as to this system, already finished their study. The duration of medical study is 6 years, i.e. 12 semesters. This composed of three cycles: I Basic biomedical sciences. The first two years represent the first cycle, which is based on the integrative principle. II. Principles of clinical medicine. The second cycle is concerned on the problem-based learning. III. Clinical preparation. The third cycle represents clinical application. In the first two years the integrative study is composed of different modules. The first module I A--Structure and functions of human body is the greatest module in the first two years, which is composed of anatomy, histology and embryology, biochemistry and physiology. The module I B--Cell biology and genetics is composed of genetics and cell biology and this module is finished by the examination after two semesters at the end of the first year.     

The feral pig (Sus scrofa,Suidae) in Cocos Island,Costa Rica: Rootings,soil alterations and erosion

Feral pigs (Sus scrofa) are of the most damaging exotic vertebrates, specially on oceanic island native communities. Feral pigs inhabit Cocos Island since 1793 and there are around 400-500 individuals. In order to quantify the impacts of the feral pigs at Cocos Island. I calculated the effect of the rooting activity and its influence on the natural erosion. During one year I walked, monthly, 15 km on trails estimating rooted area by transect and rooting recurrence. During eight months I compared erosion rates with and without rootings. I estimated the annual rooting rate between 10 and 20% of the total island surface. The rooted area was the only measured variable which correlated with the soil erosion rate. The erosion rate without rootings was 23.6 kg/ha/year and with rootings was 200.4 kg/ha/year (P < 0.01). The disturbances provoked by the rootings were not scattered homogeneously through the island. The rootings, together with the natural landslides, dominate the soil disturbance pattern at Cocos Island. This study suggests that the presence of feral pigs produces more erosion than the one that would naturally occur without feral pigs at Cocos Island.     

Experience with 125I brachytherapy as a radical treatment for prostate cancer at the Russian X-ray Radiology Research Center

Prostate cancer is one of the most common malignancies among males. 125I brachytherapy is a current, effective, comparatively safe, and easy-to-reproduce treatment. The Russian X-ray Radiology Research Center has implanted 125I microsources in patients with localized and locally advanced prostate cancer since 2003; 689 125I implantations were performed in the past year. Tumor-specific survival after brachytherapy did not differ greatly from that following radical prostatectomy. Thus, brachytherapy is a current high-tech treatment for prostate cancer. This therapy shows fewer adverse postradiation effects than radiation teletherapy.