Mark-recapture may reveal more about ecology than about population trends: Demography of a threatened ghost bat (Macroderma gigas) population

Since European settlement in Australia, the geographical range of ghost bats (Macroderma gigas) has contracted northwards. Ghost bats are thought to occur in disjunct populations with little interpopulation migration, raising concerns over the current status and future viability of the southernmost colony, which has also been threatened by mining activity. To address these concerns, demographic parameters of the southernmost colony were estimated from a mark-recapture study conducted during 1975-1981. Female bats gave birth to a single young in late spring, but only 40% (22-70%, 95% CI) of females bred in their second year, increasing to 93% (87-97%, 95% CI) for females greater than or equal to 2 years old. Sixty-five percent of juveniles caught were female. Annual adult survival ranged between 0.57-0.77 for females and 0.43-0.66 for males, and was lowest over winter-spring and greatest in autumn-winter. Juvenile survival for the first year ranged between 0.35-0.46 for females and 0.29-0.42 for males. Adult survival varied among seasons, was negatively associated with rainfall, but was not associated with temperature beyond being lower in late winter. Poor survival may result from the inferior daytime roosts that bats must use if water seepage forces them to leave their normal roosts. Although these age-specific rates of fecundity and survival suggested a declining population, mark-recapture estimates of the population trend indicated stability over the study period. Counts at daytime roosts also suggested a population decline, but were considered unreliable because of an increasing tendency of bats to avoid detection. It is therefore likely that some assumptions in estimating survival were violated. These results provide a caution against the uncritical use of population projections derived from mark-recapture estimates of demographic parameters, and the use of untested indices as the basis for conservation decisions.

Fatigue-related changes in torque output and electromyographic parameters of trunk muscles during isometric axial rotation exertion - An investigation in patients with back pain and in healthy subjects

Study Design. A cross-sectional case-control study. Objectives. To examine the effect of fatigue on torque output as well as electromyographic frequency and amplitude values of trunk muscles during isometric axial rotation exertion in back pain patients and to compare the results with a matched control group. Summary of Background Data. Back pain patients exhibited different activation strategies in trunk muscles during the axial rotation exertions. Fatigue changes of abdominal and back muscles during axial rotation exertion have not been examined in patients with back pain. Methods. Twelve back pain patients and 12 matched controls performed isometric fatiguing axial rotation to both sides at 80% maximum voluntary contraction in a standing position. During the fatiguing exertion, electromyographic changes of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum, and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were also measured. Results. No difference in the endurance capacity was found between back pain and control groups. At the initial period of the exertion, back pain patients demonstrated a statistical trend (P = 0.058) of greater sagittal coupling torque as well as lower activity of rectus abdominis and multifidus and higher activity in external oblique. During the fatigue process similar changes of coupling torque were demonstrated in both sagittal and coronal planes, but a smaller fatigue rate for right external oblique, increase in median frequency for latissimus dorsi, and lesser increase in activity for back muscles were found in the back pain group compared with the control group. Conclusions. Alterations in electromyographic activation and fatigue rates of abdominal and back muscles demonstrated during the fatigue process provide insights into the muscle dysfunctions in back pain and may help clinicians to devise more rational treatment strategies.

A variable stepsize implementation for stochastic differential equations

Stochastic differential equations (SDEs) arise from physical systems where the parameters describing the system can only be estimated or are subject to noise. Much work has been done recently on developing higher order Runge-Kutta methods for solving SDEs numerically. Fixed stepsize implementations of numerical methods have limitations when, for example, the SDE being solved is stiff as this forces the stepsize to be very small. This paper presents a completely general variable stepsize implementation of an embedded Runge Kutta pair for solving SDEs numerically; in this implementation, there is no restriction on the value used for the stepsize, and it is demonstrated that the integration remains on the correct Brownian path.

Influence of synthesis parameters on the formation of mesoporous SAPOs

The synthesis and characterization of high-quality mesoporous silicoaluminophosphates (SAPOs) with a hexagonally arranged pore structure and a good thermal stability are described. The influence of some important synthesis parameters including temperature, time, and Si content in the synthesis gel was examined. The local environments of Al, P, and Si were investigated using MAS NMR spectroscopy. The acidity of the mesoporous SAPOs was studied and compared with those of aluminosilicate MCM-41 and SAPO-5. Results show that both the synthesis temperature and time have a significant impact on the formation of mesoporous SAPOs, whereas the presence of Si in the synthesis gel has a direct influence on the structure type and the quality of the resulting mesoporous SAPO materials. High-quality mesoporous SAPOs can be synthesized from the synthesis gels with Si/Al ratio smaller than 0.5 in the presence of cationic surfactants in a weakly basic aqueous solution. The mesoporous SAPO materials show interesting acidity properties, possessing both strong and mild sites. (C) 2002 Elsevier Science Inc. All rights reserved.

Modelling the activated sludge flocculation process combining laser light diffraction particle sizing and population balance modelling (PBM)

A technique based on laser light diffraction is shown to be successful in collecting on-line experimental data. Time series of floc size distributions (FSD) under different shear rates (G) and calcium additions were collected. The steady state mass mean diameter decreased with increasing shear rate G and increased when calcium additions exceeded 8 mg/l. A so-called population balance model (PBM) was used to describe the experimental data, This kind of model describes both aggregation and breakage through birth and death terms. A discretised PBM was used since analytical solutions of the integro-partial differential equations are non-existing. Despite the complexity of the model, only 2 parameters need to be estimated: the aggregation rate and the breakage rate. The model seems, however, to lack flexibility. Also, the description of the floc size distribution (FSD) in time is not accurate.

Airborne Pinus pollen in the atmosphere of Brisbane, Australia and relationships with meteorological parameters

Relationships between weather parameters andairborne pollen loads of Pinus inBrisbane, Australia have been investigated overthe five-year period, June 1994–May 1999.Pinus pollen accounts for 4.5% of the annualairborne pollen load in Brisbane where thePinus season is confined to the winter months,July–early September. During the samplingperiod loads of 11–>100 grains m3 wererecorded on 24 days and 1–10 grains m3 on204 days. The onset and peak dates wereconsistent across each season, whereas the enddates varied. The onset of the Pinuspollen season coincided with the coolestaverage monthly temperatures (< 22°C),lowest rainfall (< 7mm), and four weeks afterdaily minimum temperatures fell to 5–9°Cin late autumn. Correlations obtained betweendaily airborne Pinus pollen counts andtemperature/rainfall parameters show thatdensities of airborne Pinus pollen arenegatively correlated with maximum temperature(p < 0.0001), minimum temperature (p < 0.0001)and rainfall (p < 0.05) during the mainpollination period. The mean duration of eachpollen season was 52 days; longer seasons wereshown to be directly related to lower averageseasonal maximum temperatures (r2 = 0.85,p = 0.025). These results signify that maximumand minimum temperatures are the majorparameters that influence the onset andduration of the Pinus pollen season inthe environs of Brisbane. Respiratory allergyis an important health issue in Brisbane,Australia, but it remains unknown whether ornot airborne Pinus pollen is acontributing factor.

Impulse-response function of splanchnic circulation with model-independent constraints: theory and experimental validation

Modeling physiological processes using tracer kinetic methods requires knowledge of the time course of the tracer concentration in blood supplying the organ. For liver studies, however, inaccessibility of the portal vein makes direct measurement of the hepatic dual-input function impossible in humans. We want to develop a method to predict the portal venous time-activity curve from measurements of an arterial time-activity curve. An impulse-response function based on a continuous distribution of washout constants is developed and validated for the gut. Experiments with simultaneous blood sampling in aorta and portal vein were made in 13 anesthetized pigs following inhalation of intravascular [O-15] CO or injections of diffusible 3-O[ C-11] methylglucose (MG). The parameters of the impulse-response function have a physiological interpretation in terms of the distribution of washout constants and are mathematically equivalent to the mean transit time ( T) and standard deviation of transit times. The results include estimates of mean transit times from the aorta to the portal vein in pigs: (T) over bar = 0.35 +/- 0.05 min for CO and 1.7 +/- 0.1 min for MG. The prediction of the portal venous time-activity curve benefits from constraining the regression fits by parameters estimated independently. This is strong evidence for the physiological relevance of the impulse-response function, which includes asymptotically, and thereby justifies kinetically, a useful and simple power law. Similarity between our parameter estimates in pigs and parameter estimates in normal humans suggests that the proposed model can be adapted for use in humans.

Blast design using measurement while drilling parameters

Measurement while drilling (MWD) techniques can provide a useful tool to aid drill and blast engineers in open cut mining. By avoiding time consuming tasks such as scan-lines and rock sample collection for laboratory tests, MWD techniques can not only save time but also improve the reliability of the blast design by providing the drill and blast engineer with the information specially tailored for use. While most mines use a standard blast pattern and charge per blasthole, based on a single rock factor for the entire bench or blast region, information derived from the MWD parameters can improve the blast design by providing more accurate rock properties for each individual blasthole. From this, decisions can be made on the most appropriate type and amount of explosive charge to place in a per blasthole or to optimise the inter-hole timing detonation time of different decks and blastholes. Where real-time calculations are feasible, the system could extend the present blast design even be used to determine the placement of subsequent holes towards a more appropriate blasthole pattern design like asymmetrical blasting.

A modified Weibull distribution

A new lifetime distribution capable of modeling a bathtub-shaped hazard-rate function is proposed. The proposed model is derived as a limiting case of the Beta Integrated Model and has both the Weibull distribution and Type I extreme value distribution as special cases. The model can be considered as another useful 3-parameter generalization of the Weibull distribution. An advantage of the model is that the model parameters can be estimated easily based on a Weibull probability paper (WPP) plot that serves as a tool for model identification. Model characterization based on the WPP plot is studied. A numerical example is provided and comparison with another Weibull extension, the exponentiated Weibull, is also discussed. The proposed model compares well with other competing models to fit data that exhibits a bathtub-shaped hazard-rate function.

Kinetic parameters associated with self-heating of New Zealand coals under adiabatic conditions

Adiabatic self-heating tests were carried out on five New Zealand coal samples ranging in rank from lignite to high-volatile bituminous. Kinetic parameters of oxidation were obtained front the self-heating curves assuming Arrhenius behaviour. The activation energy E (kJ mol(-1)) and the pre-exponential factor A (s(-1)) were determined in the temperature range of 70-140 degreesC. The activation energy exhibited a definite rank relationship with a minimum E of 55 kJ mol(-1) occurring at a Suggate rank of similar to6.2 corresponding to subbituminous C. Either side of this rank there was a noticeable increase in the activation energy indicating lower reactivity of the coal. A similar rank trend was also observed in the R-70 self-heating rate index values that were taken from the initial portion of the self-heating curve front 40 to 70 degreesC. From these results it is clear that the adiabatic method is capable of providing reliable kinetic parameters of coal oxidation.

Bovine-serum-albumin-containing receptor phase better predicts transdermal absorption parameters for lipophilic compounds

Based on the hypothesis that limited receptor solubility of lipophilic compounds may result in lower observed permeability parameters, the aim of this study was to determine the in vitro human epidermal permeability coefficients and membrane retention of a series of aliphatic alcohols (C1-C10, log p -0.72 to 4.06) using two different receptor solutions (water and 4% bovine serum albumin in phosphate-buffered saline). Aqueous solutions of radiolabeled alcohols were dosed into the stratum corneum side of membranes mounted in side-by-side glass diffusion cells. Appearance of alcohol in the receptor compartment filled with either of the two solutions was monitored over a 7 h period when both stratum corneum (assessed by tape stripping) and the remaining epidermis levels of radioactivity were determined. In a separate study the degree of binding of alcohols to 4% bovine serum albumin was determined. The data showed increased receptor phase solubility in the bovine serum albumin solution and higher permeability coefficients for the more lipophilic alcohols in the series. No changes were seen in the partitioning of the alcohols from the vehicle into either the stratum corneum or tape-stripped epidermis with the two receptor phases; however, a decrease in the amount of the more lipophilic alcohols partitioning into the water receptor phase from the tape-stripped epidermis was observed. We conclude that bovine serum albumin receptor phase allows better estimation of real permeability parameters for lipophilic compounds due to its increased solubility capacity and we question whether permeability parameters for lipophilic solutes from older data sets based on aqueous receptor phases are completely reliable.

Part 1. Growth, carcass and meat quality parameters of male goats: effects of genotype and liveweight at slaughter

Male kids (110) from six goat genotypes, i.e. Boer x Angora (BA), Boer x Feral (1317), Boer x Saanen (BS), Feral x Feral (FF), Saanen x Angora (SA) and Saanen x Feral (SF) and two slaughter weight groups, i.e. Capretto and Chevon (liveweight at slaughter 14-22 and 30-35 kg, respectively) were compared for growth, carcass and meat quality characteristics. Due to their better growth rate, kids from BS and SF genotypes reached the required liveweight for slaughter earlier than kids from other Genotypes used in the study. Chevon kids had a significantly (P < 0.05) lower average daily gain (119 g per day) compared to Capretto kids (171 g per day). SA, SF and FF kids deposited more internal fat in comparison to kids from other genotypes. The dressing percentage of kids ranged from 51 to 54%, with significant differences between genotypes. BS and SF kids had longer carcasses. while BF kids had larger eye muscle area compared to other genotypes. Goat carcasses had a thin subcutaneous fat cover (1.6-2.2 mm). Genotype had a significant (P < 0.05) influence on cooking loss, pigment concentration and muscle colour parameters (CIE L*, a* and b* values). As denoted by the higher V and fibre optic probe values and lower subjective muscle score, the longissimus muscle colour was lighter for BS kids than other genotypes. Cooked meat from the BF kids had lower shear force values and better sensory scores compared to other genotypes. A significant (P < 0.05) decrease in muscle tenderness was observed from Capretto to Chevon carcasses, whereas cooked meat from these two slaughter weight groups was equally accepted (P > 0.05) by the panellists. (C) 2003 Elsevier Science B.V. All rights reserved.

New fluorescence parameters for monitoring photosynthesis in plants - 1. The effect of illumination on the fluorescence parameters of the JIP-test

Chlorophyll fluorescence measurements have a wide range of applications from basic understanding of photosynthesis functioning to plant environmental stress responses and direct assessments of plant health. The measured signal is the fluorescence intensity (expressed in relative units) and the most meaningful data are derived from the time dependent increase in fluorescence intensity achieved upon application of continuous bright light to a previously dark adapted sample. The fluorescence response changes over time and is termed the Kautsky curve or chlorophyll fluorescence transient. Recently, Strasser and Strasser (1995) formulated a group of fluorescence parameters, called the JIP-test, that quantify the stepwise flow of energy through Photosystem II, using input data from the fluorescence transient. The purpose of this study was to establish relationships between the biochemical reactions occurring in PS II and specific JIP-test parameters. This was approached using isolated systems that facilitated the addition of modifying agents, a PS II electron transport inhibitor, an electron acceptor and an uncoupler, whose effects on PS II activity are well documented in the literature. The alteration to PS II activity caused by each of these compounds could then be monitored through the JIP-test parameters and compared and contrasted with the literature. The known alteration in PS II activity of Chenopodium album atrazine resistant and sensitive biotypes was also used to gauge the effectiveness and sensitivity of the JIP-test. The information gained from the in vitro study was successfully applied to an in situ study. This is the first in a series of four papers. It shows that the trapping parameters of the JIP-test were most affected by illumination and that the reduction in trapping had a run-on effect to inhibit electron transport. When irradiance exposure proceeded to photoinhibition, the electron transport probability parameter was greatly reduced and dissipation significantly increased. These results illustrate the advantage of monitoring a number of fluorescence parameters over the use of just one, which is often the case when the F-V/F-M ratio is used.