Open Capture–Recapture Models with Heterogeneity: II. Jolly–Seber Model

Summary Estimation of abundance is important in both open and closed population capture–recapture analysis, but unmodeled heterogeneity of capture probability leads to negative bias in abundance estimates. This article defines and develops a suite of open population capture–recapture models using finite mixtures to model heterogeneity of capture and survival probabilities. Model comparisons and parameter estimation use likelihood‐based methods. A real example is analyzed, and simulations are used to check the main features of the heterogeneous models, especially the quality of estimation of abundance, survival, recruitment, and turnover. The two major advances in this article are the provision of realistic abundance estimates that take account of heterogenetiy of capture, and an appraisal of the amount of overestimation of survival arising from conditioning on the first capture when heterogeneity of survival is present.     

13C labeling of plant assimilates using a simple canopy-scale open air system

A simple system based on web-FACE technology was designed and implemented as an approach to label plant-assimilated carbon (C) with ¹³C. The labeling system avoids the use of a chamber or other enclosure, instead distributing CO₂ heavily enriched in ¹³C at near atmospheric concentrations to the tree foliage through the use of porous tubing. The system was applied to three plantation grown juvenile larch (Larix spp.) trees during the daylight hours over the course of five days in the middle of the growing season. Relative to control trees, fumigation with enriched CO₂ resulted in significantly ¹³C-enriched foliar respiration and nighttime soil respiration. Enrichment was also created in the foliar tissue, but differences between labeled and control trees were not statistically significant. Temporal and spatial variation in the strength of the isotopic label did occur, and modifications to the system are suggested to limit the variation. The approach should enable the implementation of pulse-chase experiments designed to understand plant source-sink relationships or experiments designed to understand the flux of C from plant roots into the soil food web. Responsible Editor: Angela Hodge.     

A situation in which a local nontoxic refuge promotes pest resistance to toxic crops

In order to delay the development of pest resistance to genetically engineered insecticidal crop varieties, it is current practice to grow "refugees" of non-toxic plants close to insecticidal crops. We model such a toxic/nontoxic crop complex as an open system with a small stream of toxin-susceptible immigrants. We find that, for intermediate values of the dominance of a pest gene for resistance to the toxin, the local refuge can spoil the benefit that is provided by the immigrant stream. We provide formulas for some important boundaries in parameter space.     

Outdoor cultivation of lutein-rich cells of <Emphasis Type="Italic">Muriellopsis</Emphasis> sp. in open ponds

The growth performance of the chlorophycean microalga Muriellopsis sp. outdoors in open tanks agitated with a paddlewheel and its ability to accumulate carotenoids have been evaluated throughout the year. The cells grown in the open system had free lutein as the main carotenoid, with violaxanthin, β-carotene, and neoxanthin also present. Lutein content of the dry biomass ranged from 0.4 to 0.6%, depending on the growth and environmental conditions. In addition, the biomass of Muriellopsis sp. had a high content in both protein and lipids with about half of the fatty acids being of the polyunsaturated type, with α-linolenic acid accounting for almost 30% of the total fatty acids. The effect of determinant parameters on the performance of the cultures in open tanks was evaluated. Operating conditions that allow the maintenance of productive cultures were established under semicontinuous regime for 9 months throughout the year. Biomass and lutein yields in the open system were not far from those in closed tubular photobioreactors, and reached productivity values of 20 g dry biomass, containing around 100 mg lutein m⁻² day⁻¹ in summer. The outdoor culture of Muriellopsis sp. in open ponds thus represents a real alternative to established systems for the production of lutein.     

Regulation of TRPV5 Single-Channel Activity by Intracellular pH

The transient receptor potential channel TRPV5 contributes to the apical entry pathway for transcellular calcium reabsorption in the kidney. Acid load causes hypercalciuria in animals and humans. We have previously reported that intracellular protons directly inhibit TRPV5. Here, we examined the effects of intracellular pH on single-channel activity of TRPV5. We found that TRPV5 channels exhibit full and subconductance open states in excised inside–out patches of Chinese hamster ovary cells. The slope conductance values (Na⁺ as a charge carrier, between −25 and −75 mV) for full and subconductance opening at intracellular pH 7.4 were 59 ± 6 and 29 ± 3 pS, respectively. Intracellular acidification caused a small decrease in single-channel conductance. Importantly, intracellular acidification decreased open probability for the full and subconductance states and increased probability for closing. To investigate how intracellular protons decrease open probability of the channel, we proposed a simple three-state model for open–subconductance–closed state transition and examined the effects of acidification on the respective forward and reverse rate constants. We found that intracellular acidification decreases opening of TRPV5 predominantly by promoting a transition from the subconductance to the closed state. Thus, intracellular acidification directly inhibits TRPV5 by causing a conformational change(s) leading to a decrease of open probability of TRPV5 as well as of the single-channel conductance. Seung-Kuy Cha and Wasey Jabbar contributed equally to this work.     

全自动生化分析仪的发展及市场概况

随着中国国内城乡国民医疗保险事业的普及和持续发展,城乡各级医院生化实验室应用自动生化分析仪的需求越来越迫切。本文就其现状作一基本论述。     

Anxiolytic effects of lavender oil inhalation on open-field behaviour in rats

To establish a valid animal model of the effects of olfactory stimuli on anxiety, a series of experiments was conducted using rats in an open-field test. Throughout, effects of lavender oil were compared with the effects of chlordiazepoxide (CDP), as a reference anxiolytic with well-known effects on open-field behaviour. Rats were exposed to lavender oil (0.1-1.0 ml) for 30 min (Experiment 1) or 1h (Experiment 2) prior to open-field test and in the open field or injected with CDP (10 mg/kg i.p.). CDP had predicted effects on behaviour, and the higher doses of lavender oil had some effects on behaviour similar to those of CDP. In Experiment 3, various combinations of pre-exposure times and amounts of lavender oil were used. With sufficient exposure time and quantity of lavender the same effects were obtained as in Experiment 2. Experiment 4 demonstrated that these behavioural effects of lavender could be obtained following pre-exposure, even if no oil was present in the open-field test. In Experiments 2-4, lavender oil increased immobility. Together, these experiments suggest that lavender oil does have anxiolytic effects in the open field, but that a sedative effect can also occur at the highest doses.     

(−)-Linalool, a naturally occurring monoterpene compound, impairs memory acquisition in the object recognition task, inhibitory avoidance test and habituation to a novel environment in rats

It is known that (−)-linalool is a competitive antagonist of NMDA receptors, which play a key role in the learning and memory processes; however, only a few studies have reported a possible interference of (−)-linalool in memory. The purpose of this study was to investigate the (−)-linalool effects on acquisition of short- and long-term memories through the objects recognition task, inhibitory avoidance test and habituation to a novel environment. Furthermore, the open field test was used to investigate the interference of (−)-linalool in motivation, locomotion and exploration by animals. Wistar male adult rats received an intraperitoneal injection (i.p.) of saline (NaCl 0.9%), tween 5% or (−)-linalool (50 or 100 mg/kg) before training in the tasks; MK-801 (0.1 mg/kg), a glutamate antagonist, was used as positive control. Short-term (STM) and long-term (LTM) memories were tested 1.5 and 24 h after training, respectively, in the inhibitory avoidance and recognition objects. The results suggested that (−)-linalool (as 50- and 100-mg/kg doses) impaired LTM acquisition, but not STM acquisition, in the object recognition task. In the inhibitory avoidance test, animals receiving linalool (both doses) showed impairment in acquisition of both memories measured. In the open field test, the animals that received (−)-linalool showed no significant difference in the crossings and latency to start the locomotion in any of the doses tested, although (−)-linalool 100 mg/kg reduced rearing behavior. When re-exposed to open field 24 h after training, the rats that received (−)-linalool 100 mg/kg showed no habituation. Taken together, these data suggested that (−)-linalool was able to impair the acquisition of memory in rats, which can be associated to (−)-linalool antagonist capacity as regards NMDA glutamatergic receptors, since other glutamate antagonists also seem to affect memory.     

Technoeconomic analysis of five microalgae-to-biofuels processes of varying complexity

The economics surrounding five algae-to-fuels process scenarios were examined. The different processes modeled were as follows: an open pond producing either triacylglycerides (TAG) or free fatty acid methyl ester (FAME), a solar-lit photobioreactor producing either FAME or free fatty acids (FFA), and a light emitting diode irradiated (LED-lighted) photobioreactor producing TAG. These processes were chosen to represent both classical and esoteric approaches presented in the open literature. Viable (or suggested) processing techniques to liberate and purify (and convert) the microalgal triacylglycerides were then modeled to accompany each growth option. The investment and cost per kg of fuel or fuel precursor for each process was determined. The open pond produced TAG at ～$7.50/kg, while the process using the LED-lit photobioreactor produced TAG at ～$33/kg. The scenario containing the solar-lit photobioreactor produced FAME at ～$25/kg, while the open pond produced FAME at ～$4/kg. The scenario containing the solar-lit photobioreactor produced FFA at ～$29/kg. The open pond scenarios appear to be closest to the $1/kg pricepoint at this time, and thus are the most viable economic options. Future technological advancements that reduce the cost of bioreactor vessels, LED lighting, and solvent recovery, may reduce the oil production costs of these scenarios to a more attractive level.     

Patent ductus arteriosus in adults – indications and possibilities for closure

Patent ductus arteriosus (PDA) is a rare diagnosis in adults, since symptoms and signs usually occur in infancy and most cases are treated shortly after diagnosis. We present two patients who were first diagnosed with PDA during adulthood. The first case represents a more severe form of PDA, where the need for closure of the PDA is obvious. In the second case the sequelae of the PDA are less clear. In both patients, closure of the PDA (surgically in one case, percutaneously in the other) was successful.