Evidence from algal bioassays of seasonal nutrient limitations in two English lakes

Comparative laboratory bioassays using Asterionella formosa and Rhodomonas lacustris as test organisms were performed from March to November 1987 on filtered water samples from two English lakes, to assess their potential fertility and to identify possible limiting nutrients. The relative growth responses (log₂ increments) per week, were measured after additions of P, Fe, Si, N, and K singly and in combinations in comparison with unenriched (control) samples. Phosphate appeared to be the major limiting element for both species throughout the year, except during the spring diatom maxima when silicon usually becomes limiting. On most occasions chelated iron increased the growth increments, particularly in combination with phosphate. In general, the bioassay results showed correspondence with the nutrient concentrations in the test waters, which showed low (< 1 µg l^–1) levels of soluble reactive phosphate during all or most of the year and depleted silicon levels in late spring. Comparison between relative (incremental) ratio and absolute (cell concentration) response was made.     

Studies on interspecies competition between the azuki bean weevil and the southern cowpea weevil

Experimental studies was made on the interspecies competition between the azuki bean weevil, Callosobruchus chinensis and the southern cowpea weevil, C. macultatus. And the following results were obtained.

1. The reverse result of competition between the two species observed under the air-tight condition and the air-free one. That is, the population of the azuki bean weevils destroyedby that of the southern cowpea weevils under the former condition and vice versa under the latter. It is thought that such a reversal is due to the difference of sensibility of each species to the air-tight condition.
2. Under the air-free condition, change of the time interval of food-supplying had no effect on the result of competition within the limits of this experiment. The population of the southern cowpea weevils was always destroyed by that of the azuki bean weevils. But there was a certain degree of correlation between the duration of co-existence and the interval of food-supplying.
3. From the results, it is possible to say that by changing the degree of air-tightness, or the time interval of food-supplying, the co-existence period and the final result of competition can be changed.
4. The different mechanism of competition between two species in the present experiment from the experiments ofUtida (1952) andYoshida (1957) were discussed.
5. A difference in the mechanism of interspecies competition and intraspecies competition was expected from the level of total population numbers of two species and the individual weight of C. chinensis.

     

Ernst Mayr as community architect: Launching the society for the study of evolution and the journalEvolution

Ernst Mayr's contributions to 20th century biology extend far beyond his defense of certain elements in evolutionary theory. At the center of mid-century efforts in American evolutionary studies to build large research communities, Mayr spearheaded campaigns to create a Society for the Study of Evolution and a dedicated journal,Evolution, in 1946. Begun to offset the prominence ofDrosophila biology and evolutionary genetics, these campaigns changed course repeatedly, as impediments appeared, tactics shifted, and compromises built a growing coalition of support. Preserved, however, were designs to balance the community and journal with careful equation of status and explicit partitioning of responsibilities within the working coalition. Choice terms such as cooperation and unity carried a strong political message. Mayr's editorship ofEvolution provides a superb example of these balancing efforts. The mid-century infrastructural activities described herein also represented aggressive attempts to leverage control across several layers of community. Leaders of these campaigns sought: (1) to promote evolutionary studies as a modernized research discipline and place it at the center of American biology, (2) to promote evolutionary studies within existing disciplines — e.g. systematics, genetics, and paleontology, (3) to foster certain research styles within evolutionary studies, and (4) to emphasize certain solutions to prominent research questions. Throughout, Mayr interjected his priorities, tactics and energy.     

Seasonal cycle of nitrogen and phytoplankton biomass in a well-mixed coastal system (Eastern English Channel)

The hydrological structure of the French coastal part of the eastern English Channel is strongly linked with tidal regimes and riverine input. Two distinct water masses are separated by a frontal area and drift along the coast in SW–NE direction. These two water masses are well-mixed during the entire year. We studied the seasonal dynamic of nitrogenous nutrients, chlorophyll a and organic particulate carbon and nitrogen at two stations, characteristic of these water masses, during the year 1994. Results show (i) a winter stock of nitrate and ammonium, (ii) a pre-bloom period corresponding to the use of ammonium, (iii) a high bloom period of short duration using nitrate, (iv) a post-bloom period with little phytoplanktonic activity probably limited by nutrients other than nitrogen and (v) an autumnal period of reconstitution of stock. The essential difference between the two stations is the importance of winter stock of nutrients and of bloom chlorophyll a concentration, with the coastal station richer than the offshore one. An assumption about the nitrogen available for new production in this area gives a value of 57% of the winter stock of inorganic nitrogen.     

REEXAMINATION OF THE ETHICS OF PLACEBO USE IN CLINICAL PRACTICE

A placebo is a substance or intervention believed to be inactive, but is administered by the healthcare professional as if it was an active medication. Unlike standard treatments, clinical use of placebo usually involves deception and is therefore ethically problematic. Our attitudes toward the clinical use of placebo, which inevitably includes deception or withholding information, have a tremendous effect on our practice regarding truth‐telling and informed consent. A casual attitude towards it weakens the current practice based on shared decision‐making and mutual trust between patients and healthcare professionals. Issues concerning the clinical use of placebo are thus intimately related to patient‐provider relationships, the public's trust in medicine, and medical education. A review of recent survey studies suggests that the clinical use of placebo appears to be fairly well accepted among healthcare professionals and is common in clinical settings in various countries. However, we think that an ethical discussion is urgently needed because of its controversial nature. If judged to be ethically wrong, the practice should end. In the present paper, we discuss the ethicality of the clinical use of placebo with deception and argue against it, concluding that it is unethical and should be banned. We will show that most arguments in favor of the clinical use of placebo can be refuted and are therefore incorrect or weak. These arguments will be presented and examined individually. Finally, we will briefly consider issues relevant to the clinical use of placebo without deception.     

Dendrochronological analysis of an English chest: Contributing to knowledge about wood supply and chest production in 16th century England

Historic furniture has a great ethnographic and historical value, as styles and designs responded to specific uses, fashion trends and the social status of the buyer or the commissioner. Placing it in an exact chronological and geographical production context increases our knowledge about preferences for materials, designs, and woodworking practices for household commodities. Here we present the results of dendrochronological research carried out on an English chest from a private collection. The chest is of a hybrid construction, with boarded sides and back, and a joined front with four carved linenfold panels. It had been described as made of Baltic oak and dating to the mid-16th century, a crucial transition period for which only a few early chests have been analysed. Our results demonstrate, however, that the wood from the lid, side boards and back originates from the south of England. Heartwood/sapwood border in the left side board has allowed an estimated felling date for the tree of between 1520 and 1552. Terminus post quem dates of the rest of the elements pre-dating this interval indicate that the chest was likely made in the second quarter of the 16th century, as initially described. Three linenfold panels show typical features of Baltic wood, whereas the fourth one has different characteristics and could have been made with English oak, but the lack of access to the tree-ring patterns hampers verifying this hypothesis. Mixture of provenances suggests a production workshop in London, although other town in the south with a major timber market cannot be discarded. The construction features are described, and two distinct marks found in the chest are discussed in the regional context of its production. To allow the compilation and inventory of such marks, the ‘Marks on Wood’ community has been created in Zenodo and is presented here.     

Printed in the Holiday Mood

Teachers' careers are often considered to consist of two parts: pre-service and in-service. In-service refers to the entire time between a teacher's entry and exit from the profession. Recent research suggests teachers' careers actually consistent of several parts, known as phases or stages and, collectively, as the career cycle. This further suggests that as they pass through different stages, teachers' professional development needs may change. This article presents a review of literature on the career cycle, examines the portion known as the “second stage,” and discusses the policy and professional development implications for music teachers.     

THE EFFECTS OF INJURY PREVENTION WARM-UP PROGRAMMES ON KNEE STRENGTH IN MALE SOCCER PLAYERS

The study investigates the effects of the 11+ and HarmoKnee injury prevention programmes on knee strength in male soccer players. Under-21-year-old players (n=36) were divided equally into: the 11+, HarmoKnee and control groups. The programmes were performed for 24 sessions (20-25 min each). The hamstrings and quadriceps strength were measured bilaterally at 60°·s^-1, 180°·s^-1 and 300°·s^-1. The concentric quadriceps peak torque (PT) of the 11+ increased by 27.7% at 300°·s^-1 in the dominant leg (p<0.05). The concentric quadriceps PT of HarmoKnee increased by 36.6%, 36.2% and 28% in the dominant leg, and by 31.3%, 31.7% and 20.05% at 60°·s^-1, 180°·s^-1 and 300°·s^-1 in the non-dominant leg respectively. In the 11+ group the concentric hamstring PT increased by 22%, 21.4% and 22.1% at 60°·s^-1, 180°·s^-1 and 300°·s^-1, respectively in the dominant leg, and by 22.3%, and 15.7% at 60°·s^-1 and 180°·s^-1, in the non-dominant leg. In the HarmoKnee group the hamstrings in the dominant leg showed an increase in PT by 32.5%, 31.3% and 14.3% at 60°·s^-1, 180°·s^-1 and 300°·s^-1, and in the non-dominant leg hamstrings PT increased by 21.1% and 19.3% at 60°·s^-1 and 180°·s^-1 respectively. The concentric hamstrings strength was significantly different between the 11+ and control groups in the dominant (p=0.01) and non-dominant legs (p=0.02). The HarmoKnee programme enhanced the concentric strength of quadriceps. The 11+ and HarmoKnee programmes are useful warm-up protocols for improving concentric hamstring strength in young professional male soccer players. The 11+ programme is more advantageous for its greater concentric hamstring strength improvement compared to the HarmoKnee programme.     

医学研究生临床生化专题全英教学的改革与实践思考

为培养高质量国际化有才能的医学研究生,对于已经学习过生物化学的国际医学留学研究生,开展了以与临床密切相关的生物化学专题为主要教学内容的全英文授课的教学实践和课程建设,取得了很好的教学效果.临床生化专题全英教学课程也可能适用于国内生物化学和医学相关专业的研究生,在今后的教学实践中需要继续研究和探索,以提高国内医学相关研究生的专业综合素质.