Effects of surgery, anesthesia and pain on reproduction and behaviour of captive and free-ranging ducks

Intra-abdominal radio transmitters are used to provide valuable information on reproduction, movement patterns, habitat use, and survival in a variety of wildlife species, including waterfowl. Pain and stress associated during capture, handling, anesthesia, and with instrumentation during surgery may have sublethal consequences, which may interfere with normal behaviour. As pain is produced by any procedure or injury that causes tissue damage, it is likely that waterfowl implanted with radio transmitters would experience pain. Also, placement of transmitters during incubation necessitates an incision into the brood patch which may have significant implications, such as altered incubation patterns resulting in delayed hatch. Therefore this study attempted to quantify the effects of pain and its treatment on captive and free-ranging waterfowl. Plasma thromboxane B2 levels indicated that two nonsteroidal anti-inflammatory drugs (flunixin and ketoprofen) may exert pharmacological effects for at least 12 hours in mallard ducks. However, use of flunixin in waterfowl cannot be recommended because of extensive muscular necrosis. Treatment isoflurane-anesthetized mallards with ketoprofen demonstrated a significant analgesic through reduction heart and respiratory rate changes in response to painful stimuli. In free-ranging mallards, longer surgeries were correlated with increased time to first nesting attempt after intra-­abdominal transmitter placement. Females that received ketoprofen took 3.5 days less to the first nesting attempt than females that received saline, indicating that analgesia was beneficial. There was no evidence to suggest that ketoprofen was harmful. Bupivacaine (local anesthetic) may be shorter acting in ducks than in mammals. Sequestration and redistribution of bupivacaine may result in delayed toxicity but mechanisms are unknown. In ruddy ducks, bupivacaine did not appear to achieve long-term analgesia or prevention of post-operative pain-related behaviours. In nesting female mallards, surgery altered incubation patterns in the 24 hour post-operative period, regardless of analgesic (ketoprofen or bupivacaine). Incubation period duration was extended in bupivacaine-treated females compared to ketoprofen-treated females, indicating that analgesia may interfere with brood patch sensation. Increases in corticosterone and progesterone were detected following surgery which may indicate stress and/or pain. The benefits of administering analgesia cannot be overlooked in minimizing effects of placement of radio transmitters on free-ranging waterfowl

Economics of education research: a review and future prospects

In this paper we offer an appraisal of the economics of education research area, charting its history as a field and discussing the ways in which economists have contributed both to education research and to education policy-making. In particular, we highlight the theoretical and methodological contributions that economists have made to the field of education during the last 50 years. Despite the success of the economics of education as a field of inquiry, we argue that some of the contributions made by economists could be limited if the economics of education is seen as quite distinct from the other disciplines working in the field of education. In these areas of common interest, economists need to work side by side with the other major disciplines in the field of education if their contribution to the field is to be maximised, particularly in terms of applying improved methodology. We conclude that the study of education acquisition and its economic and social impact in the economics of education research area is very likely to remain a fertile research ground. Acknowledgement

Are Asians comfortable with discussing death in health valuation studies? A study in multi-ethnic Singapore

BACKGROUND To characterize ease in discussing death (EID) and its influence on health valuation in a multi-ethnic Asian population and to determine the acceptability of various descriptors of death and "pits"/"all-worst" in health valuation. METHODS In-depth interviews (English or mother-tongue) among adult Chinese, Malay and Indian Singaporeans selected to represent both genders and a wide range of ages/educational levels. Subjects rated using 0–10 visual analogue scales (VAS): (1) EID, (2) acceptability of 8 descriptors for death, and (3) appropriateness of "pits" and "all-worst" as descriptors for the worst possible health state. Subjects also valued 3 health states using VAS followed by time trade-off (TTO). The influence of sociocultural variables on EID and these descriptors was studied using univariable analyses and multiple linear regression (MLR). The influence of EID on VAS/TTO utilities with adjustment for sociocultural variables was assessed using MLR. RESULTS Subjects (n = 63, 35% Chinese, 32% Malay, median age 44 years) were generally comfortable with discussing death (median EID: 8.0). Only education significantly influenced EID (p = 0.045). EID correlated weakly with VAS/TTO scores (range: VAS: -0.23 to 0.07; TTO: -0.14 to 0.11). All subjects felt "passed away", "departed" and "deceased" were most acceptable (median acceptability: 8.0) while "sudden death" and "immediate death" were least acceptable (median acceptability: 5.0). Subjects clearly preferred "all-worst" to "pits" (63% vs. 19%, p < 0.001). CONCLUSION Singaporeans were generally comfortable with discussing death and had clear preferences for several descriptors of death and for "all-worst". EID is unlikely to influence health preference measurement in health valuation studies

The role of body rotation in bacterial flagellar bundling

In bacterial chemotaxis, E. coli cells drift up chemical gradients by a series of runs and tumbles. Runs are periods of directed swimming, and tumbles are abrupt changes in swimming direction. Near the beginning of each run, the rotating helical flagellar filaments which propel the cell form a bundle. Using resistive-force theory, we show that the counter-rotation of the cell body necessary for torque balance is sufficient to wrap the filaments into a bundle, even in the absence of the swirling flows produced by each individual filament

Overeducation across British regions

This paper analyses levels of over-education and wage returns to education for males across eleven regions of the UK using Labour Force Survey data. Significant differences are found in the probability of being over-educated across regions; also, differences are found in the return to the ‘correct’ level of education in each region, in each case associated with flexibility of movement between and into particular regions, which determines the ease of job matching. Furthermore, evidence is found that, after controlling for the level of education acquired, there exists a premium to the ‘correct’ level of education, which varies across UK regions

Nonlinear instability in flagellar dynamics: a notel modulation mechanism in sperm migration

Throughout biology, cells and organisms use flagella and cilia to propel fluid and achieve motility. The beating of these organelles, and the corresponding ability to sense, respond to and modulate this beat is central to many processes in health and disease. While the mechanics of flagellum–fluid interaction has been the subject of extensive mathematical studies, these models have been restricted to being geometrically linear or weakly nonlinear, despite the high curvatures observed physiologically. We study the effect of geometrical nonlinearity, focusing on the spermatozoon flagellum. For a wide range of physiologically relevant parameters, the nonlinear model predicts that flagellar compression by the internal forces initiates an effective buckling behaviour, leading to a symmetry-breaking bifurcation that causes profound and complicated changes in the waveform and swimming trajectory, as well as the breakdown of the linear theory. The emergent waveform also induces curved swimming in an otherwise symmetric system, with the swimming trajectory being sensitive to head shape—no signalling or asymmetric forces are required. We conclude that nonlinear models are essential in understanding the flagellar waveform in migratory human sperm; these models will also be invaluable in understanding motile flagella and cilia in other systems

Clinical implications and utility of field cancerization

Cancer begins with multiple cumulative epigenetic and genetic alterations that sequencially transform a cell, or a group of cells in a particular organ. The early genetic events might lead to clonal expansion of pre-neoplastic daughter cells in a particular tumor field. Subsequent genomic changes in some of these cells drive them towards the malignant phenotype. These transformed cells are diagnosed histopathologically as cancers owing to changes in cell morphology. Conceivably, a population of daughter cells with early genetic changes (without histopathology) remain in the organ, demonstrating the concept of field cancerization. With present technological advancement, including laser capture microdisection and high-throughput genomic technologies, carefully designed studies using appropriate control tissue will enable identification of important molecular signatures in these genetically transformed but histologically normal cells. Such tumor-specific biomarkers should have excellent clinical utility. This review examines the concept of field cancerization in several cancers and its possible utility in four areas of oncology; risk assessment, early cancer detection, monitoring of tumor progression and definition of tumor margins