Mimicry on the edge: why do mimics vary in resemblance to their model in different parts of their geographical range?

Batesian mimics-benign species that predators avoid because they resemble a dangerous species-often vary geographically in resemblance to their model. Such geographical variation in mimic-model resemblance may reflect geographical variation in model abundance. Natural selection should favour even poor mimics where their model is common, but only good mimics where their model is rare. We tested these predictions in a snake-mimicry complex where the geographical range of the mimic extends beyond that of its model. Mimics on the edge of their model's range (where the model was rare) resembled the model more closely than did mimics in the centre of their model's range (where the model was common). When free-ranging natural predators on the edge of the model's range were given a choice of attacking replicas of good or poor mimics, they avoided only good mimics. By contrast, those in the centre of the model's range attacked good and poor mimics equally frequently. Generally, although poor mimics may persist in areas where their model is common, only the best mimics should occur in areas where their model is rare. Thus, counter-intuitively, the best mimics may occur on the edge of their model's range.     

Ecology of two-spotted ladybird, Adalia bipunctata: a review

Abstract:  Adalia bipunctata (Linnaeus) is a generalist aphidophagous ladybird having a wide prey range. It exhibits complex polymorphism. We reviewed the information on its general characteristics, polymorphism, sexual activity, foraging behaviour, food range and prey suitability, growth and development, heterospecific interactions including natural enemies, and its biocontrol potential. Although a poor biocontrol agent (only successful against aphid, Dysaphis plantaginea in Switzerland), it was used in the past as a good model to test various hypotheses and models facilitating ecological understanding in insects. In the present review, the empirical data are interpreted and inferences drawn and a checklist of its prey is provided.     

The Comparative Effects of Chloramines on a Range of Nematodes

Chloramine-T (sodium p-toluene sulfonchloramide) was a good surface sterilant for Ditylenchus dipsaci, however it was somewhat nematicidal. These properties were presumably associated with its properties as an oxidizing chlorine. Other chloramines tested were also toxic. Its possible use as a nematicide is suggested in relation to dosage and phytotoxicity. The comparative effects of chloramines on a wide range of freeliving soil nematodes and freeliving infective larvae of animal parasitic forms are included.     

Carnivore translocations and conservation: insights from population models and field data for fishers (Martes pennanti)

Translocations are frequently used to restore extirpated carnivore populations. Understanding the factors that influence translocation success is important because carnivore translocations can be time consuming, expensive, and controversial. Using population viability software, we modeled reintroductions of the fisher, a candidate for endangered or threatened status in the Pacific states of the US. Our model predicts that the most important factor influencing successful re-establishment of a fisher population is the number of adult females reintroduced (provided some males are also released). Data from 38 translocations of fishers in North America, including 30 reintroductions, 5 augmentations and 3 introductions, show that the number of females released was, indeed, a good predictor of success but that the number of males released, geographic region and proximity of the source population to the release site were also important predictors. The contradiction between model and data regarding males may relate to the assumption in the model that all males are equally good breeders. We hypothesize that many males may need to be released to insure a sufficient number of good breeders are included, probably large males. Seventy-seven percent of reintroductions with known outcomes (success or failure) succeeded; all 5 augmentations succeeded; but none of the 3 introductions succeeded. Reintroductions were instrumental in reestablishing fisher populations within their historical range and expanding the range from its most-contracted state (43% of the historical range) to its current state (68% of the historical range). To increase the likelihood of translocation success, we recommend that managers: 1) release as many fishers as possible, 2) release more females than males (55-60% females) when possible, 3) release as many adults as possible, especially large males, 4) release fishers from a nearby source population, 5) conduct a formal feasibility assessment, and 6) develop a comprehensive implementation plan that includes an active monitoring program.     

Flexible dispersal strategies in native and non‐native ranges: environmental quality and the ‘good–stay,bad–disperse’ rule

Dispersal strategies are one of the most important determinants of range dynamics and a surrogate for invasiveness. We tested three inter‐related hypotheses derived from demographic and ecological models: (H₁) short‐distance dispersal strategies arise at native range margins due to their demographic advantage; (H₂) in non‐native areas a high diffusion rate is favoured at the advancing range front for niche filling; (H₃) environmental deterioration can increase dispersal and lead to a ‘good–stay, bad–disperse’ strategy. Spatially and temporally explicit rates of spread and dispersal kernels of the European starling Sturnus vulgaris were generated for its native range (Britain) using ringing records from 1909 to 2008, and for a non‐native area (South Africa) using ringing data and distributional records since its introduction in 1897. There was a marked spatial and temporal variation in the rate of spread within both native and non‐native ranges. In the native range the rate of spread declined with increasing distance from the species’ European distribution (contradicting H₁). In the non‐native range the rate of spread increased with distance from the introduction locality (supporting H₂). The annual rate of spread in the native range also increased significantly when environmental conditions were deteriorating as indicated by marked population declines and relatively low abundance (H₃), providing clear evidence for flexible dispersal strategies based on a ‘good–stay, bad–disperse’ rule. Starlings’ dispersal kernel followed an inverse power law and showed strong anisotropy and significant divergence between native and invasive populations, suggesting a flexible strategy comprising a dynamic response to spatial and temporal environmental variation with implications for predicting dispersal and range dynamics arising from environmental change.     

An index of functional diversity

Abstract. Functional diversity has been seen as the key to predicting the stability, invasibility, resource capture, nutrient cycling and productivity of communities. However, it has been unclear how to estimate it. Ten criteria for an index of functional diversity are developed. These include that it should reflect the range of characters present and the abundance of the species with those characters in the community, and be unaffected by the measurement units used or by the number of species. An index that meets all ten criteria, FD_var, is investigated. It is based on the variance in characters, weighted by the abundance of the species with those characters. Tested with artificial and randomly generated data, it showed reasonable use of the 0 ‐ 1 range (mean 0.60, range 0.0009 ‐ 0.975) and intuitive behaviour. Tested with field data from eight sites in New Zealand, it gave a good spread of values (mean 0.65, range across sites 0.34 ‐ 0.84), showed good ability to distinguish between the communities and its performance was ecologically intuitive. Illustrative correlations are made with mean annual temperature and soil fertility, determined by a bio‐assay. FD_var is recommended for general use.     

Key composition optimization of meat processed protein source by vacuum freeze-drying technology

Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined.     

Leaf-spot disease on European mistletoe (<Emphasis Type="Italic">Viscum album</Emphasis>) caused by <Emphasis Type="Italic">Phaeobotryosphaeria visci</Emphasis>: a potential candidate for biological control

Viscum album (European mistletoe), a perennial, evergreen, hemiparasitic shrub, infects a wide range of woody species. It adversely affects the height and diameter of growth and it is associated with increased mortality of its hosts. There is no effective control methods against it. We have found a specific hyperparasitic fungus, which can completely destroy European mistletoe by infecting its branches, leaves and berries. Both morphological and molecular identification, based on ribosomal internal transcribed spacer sequences (rDNA-ITS), established its identity as Phaeobotryosphaeria visci. Our analysis also revealed unexpected ITS variability, as compared to the previous studies, that needs to be considered in identifying of this pathogen. Because of its efficient pathogenicity this fungus might be a good candidate for biological control of mistletoe.     

HPLC analysis of the second-generation antidepressant sertraline and its main metabolite N-desmethylsertraline in human plasma

A liquid chromatographic method with ultraviolet detection was developed for the analysis of the recent antidepressant sertraline and its main metabolite N-desmethylsertraline in human plasma. The analytes were separated on a C8 reversed phase column, using a mobile phase composed of acetonitrile and a 12.3 mM, pH 3.0 phosphate buffer containing 0.1% triethylamine (35:65, v/v). Clomipramine was used as the Internal Standard. Using a solid phase extraction procedure with C2 cartridges high extraction yields (>94%) and good purification from matrix interference were obtained. Good linearity was obtained in the 7.5-250.0 ng mL(-1) range for sertraline and in the 10-500 ng mL(-1) range for N-desmethylsertraline. The analytical method was validated in terms of precision, extraction yield and accuracy. These assays gave R.S.D.% values for precision always lower than 3.9% and mean accuracy higher than 90%. Thanks to its good selectivity, the method proved to be suitable for the analysis of plasma samples from patients treated with sertraline as either monotherapy or polypharmacy.     

Coding of stimulus intensity in an olfactory receptor neuron: Role of neuron spatial extent and passive dendritic backpropagation of action potentials

The olfactory receptor neuron provides a good opportunity to analyze a biophysical model of a single neuron because its dendritic structure is simple and even close to a cylinder in the case of the moth sex-pheromone receptor cell. We have considered this cylindrical case and studied two main problems. First, we were concerned with the effect of the neuron's length on the receptor potential for a constant stimulus-induced conductance change. An analytical solution for the receptor potential was determined by using input, resistances. It was shown that the longer the neuron, the greater its ability to code over a wide range of values of the intensity of the stimulus. Second, we studied numerically the passive backpropagation of action potentials into the dendrite and its influence on the firing frequency. While propagating along the dendrite the action potential decreases in amplitude and its shape becomes rounded. The firing frequency in the model with backpropagation was found to be greater than that obtained analytically in the absence of backpropagation. However, for any given conductance change, when normalized with respect to their maxima, both firing frequencies were found to be very similar over a wide range of parameter values. Therefore, the actual firing rate (with backpropagation) may be approximated by the analytical solution without backpropagation if the actual firing rate for a large conductance change is known.     

1,2,3-Triazolylalkylribitol derivatives as nucleoside hydrolase inhibitors

A range of novel 1,2,3-triazolylalkylribitol derivatives were synthesized and evaluated as nucleoside hydrolase inhibitors. The most active compound (11a) has low micromolar potency and is structurally diverse from previously reported nucleoside hydrolase inhibitors, which, along with the simplicity of the chemistry involved in its synthesis, makes it a good lead for the further development of novel nucleoside hydrolase inhibitors.     

Natural electroactive hydrogel from soy protein isolation

A natural electroactive protein hydrogel was prepared from soy protein isolate (SPI) solution by cross-linking with epichlorohydrin. Under electrical stimulus, such SPI hydrogel quickly bends toward one electrode, showing a good electroactivity. Because of its amphoteric nature, the SPI hydrogel bends either toward the anode (pH < 6) or cathode (pH > 6), depending on the pH of the electrolyte solution. Other factors, such as electric field strength, ionic strength and gel thickness also influence the electromechanical behavior of the SPI hydrogels. Moreover, this SPI hydrogel exhibits a good electroactive behavior under strong acidic (pH = 2 - 3) or basic (pH = 11 - 12) solutions, which is a significant improvement over two other kinds of natural electroactive hydrogels, i.e., chitosan/carboxymethylcellulose and chitosan/carboxymethylchitosan hydrogel, which we reported previously. The wide pH range and good electroactivity of this natural protein hydrogel suggests its great potential for microsensor and actuator applications, especially in the biomedical field, and also to increase the scope of natural polymer-based electroactive hydrogels.     

Spatial memory of Meriones libycus (Rodienta, Gerbillidae)]

Meriones libycus, a desert rodent with a large home range, has a good spatial memory over at least 90 days, which makes it able to travel for a long way and come back to its nest. Males have a better spatial memory than females.     

Net proton charge of beta- and kappa-casein in concentrated aqueous electrolyte solutions

Titration experiments have been carried out in order to measure the net proton charge of beta- and kappa-casein in NaCl solutions at 0.1 M and 1 M salt concentrations, at 4 degrees C, in the pH range between 5.5 and 10.5. Experimental data are compared with model values calculated through pK(a)'s of titrable groups neglecting the electrostatic perturbation term (deltapK(a)) in order to evaluate the magnitude of the error caused by this approximation and to delimit its effectiveness. At both ionic strengths, the agreement is good for kappa-casein in the pH range [5.5, 9.5], while errors of up to 2 charges are observed for beta-casein in the same range. These deviations are likely to be caused by strong electrostatic effects induced by the high density of negative charges of beta-casein 1-21 peptide. In order to account for these electrostatic effects, the net proton charge on this peptide is evaluated through a model based on the counterion condensation theory developed for the titration of polyelectrolytes with different types of ionizable groups.     

Estimating the responsiveness of an instrument using more than two repeated measures

The responsiveness of a measuring instrument is its ability to detect change over time. A commonly used index of responsiveness is the effect size for paired differences. This paper generalizes the effect size for paired differences to more than two repeated observations per subject. The sampling distribution of the generalized responsiveness statistic, Rt, is simulated for a range of plausible parameter values and for a range of sample sizes varying both the number of subjects (n) and the number of observations per subject (t). The coverage properties of confidence intervals constructed by four methods are compared. Confidence intervals based on jackknife estimates of the standard error and bias of Rt have good coverage properties even when n and t are small. The methods are used to determine which of two standard quality-of-life measures is more responsive to improvements in quality of life following surgery for early-stage breast cancer.     

A PR-quadtree based multi-dimensional indexing for complex query in a cloud system

The state-of-the-art indexing mechanisms for distributed cloud data management systems can not support complex queries, such as multi-dimensional query and range query. To solve this problem, we propose a multi-dimensional indexing mechanism named PR-Chord to support complex queries. PR-Chord is composed of the global index named PR-Index and the Chord network. The multi-dimensional space formed by the range of the multi-dimensional data is divided into hyper-rectangle spaces equally. The PR-Index is a hierarchical index structure based on the improved PR quadtree to index these spaces. The complex query is transformed into the query of leaf nodes of PR-Index. We design the algorithms of query, insertion and deletion to support complex queries. Since PR-Index does not store the multi-dimensional data, its maintenance cost is zero. PR-Chord has the advantages of load balancing and simple algorithm. The experiment results demonstrate that PR-Chord has good query efficiency.     

Conditions of appearance of local response and action potential in a simple mathematical model of nerve

A simple mathematical model of a nerve fibre is proposed. According to the model the current-voltage relation for the peak Na-current is represented as a broken line. It is shown that within the potential range, where the differential (slope) Na-conductance isnegative but its absolutevalue is smaller than the membrane conductance, the fibre gives a subthreshold local response. Within the range, where differential Na-conductance is negative and has absolute value larger than the membrane conductance, the action potential arises, the rise being independent on the strength of the stimulus and conditioned only by the membrane parameters. A simple formula is obtained which describes the relation between the strength of the threshold stimulus, I, and its duration, t₀. There are two parameters in this formula, which can be measured independently: the time constant of the membrane and the lag-period in the Na-current. Insertion of these parameters into the formula allows one to construct a theoretical I-t₀ curve in good agreement with experiment.     

Sensitivity-enhancement of wavelength-modulation surface plasmon resonance biosensor for human complement factor 4

Sandwich and colloidal Au techniques for enhancing the sensitivity of a wavelength-modulation surface plasmon resonance (SPR) immunosensor are demonstrated by the detection of human complement factor 4 (C4). The design of the wavelength-modulation SPR biosensor is based on fixing the incident angle of light and measuring the reflected intensity of light in the wavelength range spanning 500-900 nm simultaneously. The human C4 had good response in the concentration range 2-20 microg/mL in the direct assay. However, in the sandwich assay, the human C4 had good response in the concentration range 0.2-20 microg/mL and the lowest concentration is 10-fold lower than that obtained by the direct assay. With human C4-Au colloidal conjugate, the human C4 had good response in the concentration range 0.1-20 microg/mL and the lowest concentration is 20-fold lower than that obtained by the direct assay. In the colloidal-Au-enhanced sandwich assay, the human C4 had good response in the concentration range 0.05-5 microg/mL and the lowest concentration is 40-fold lower than that obtained by the direct assay. Under selected experimental conditions, the reproducibility, sensitivity, and reversibility of the enhanced SPR immunoassay are very satisfactory. The results represent potentially significant advantages in the sensitivity of SPR biosensors.     

Synthesis of phosphorothioamidites derived from 3'-thio-3'-deoxythymidine and 3'-thio-2',3'-dideoxycytidine and the automated synthesis of oligodeoxynucleotides containing a 3'-S-phosphorothiolate linkage

The synthesis of N4-benzoyl-5′-O-dimethoxytrityl-2′,3′-dideoxy-3′-thiocytidine and its phosphorothioamidite is described for the first time, together with a shortened procedure for the preparation of 5′-O-dimethoxytrityl-3′-deoxy-3′-thiothymidine and its corresponding phosphorothioamidite. The first fully automated coupling procedure for the incorporation of a phosphorothioamidite into a synthetic oligodeoxynucleotide has been developed, which conveniently uses routine activators and reagents. Coupling yields using this protocol were in the range of 85–90% and good yields of singularly modified oligonucleotides were obtained. Coupling yields were also equally good when performed on either a 0.2 or 1 µmol reaction column, thus facilitating large scale syntheses required for mechanistic studies.     

从玉米胚中大量制备植物钙调素

从每公斤萌发２４ｈ的玉米胚丙酮粉中可提纯得６３ｍｇ的钙调素（ＣａＭ）,这是目前从每公斤植物材料中所提纯得ＣａＭ的最高记录。对其理化性质的研究表明,玉米胚ＣａＭ 有较高的生物学活性,能较好地激活磷酸二酯酶,其紫色吸收光谱,ＳＤＳ－ＰＡＧＥ电泳行为及氨基酸组成与其它的植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ的适宜材料。