The orientation behaviour of the lesser spearnosed bat, Phyllostomus discolor (Chiroptera) in a model roost

The orientation behaviour of bats (Phyllostomus discolor, Phyllostomidae), flying inside an octagonal roost-like chamber (ø: 100cm; h: 150cm) was examined.It has been shown that the bats begin turning manoeuvres during flight by turning their head towards the direction they intend to proceed to. During early phases of the flights, cumulative navigation errors were evident, indicating that endogenous spatial information plays a major role in the orientation of the bats. During later phases of the flight this error is diminished again. So it can be concluded that the bats start to use exogenous spatial information for orientation while approaching the target.In order to investigate the relative importance of vision, echolocation and endogenous spatial information for approaching the roost, the landing lattices inside the test arena were changed for non-grid dummies. We found that: 1. combined visual and endogenous information are more important than echoacoustical cues, 2. the bats learned quickly to switch their orientation behaviour in order to get a better performance in avoiding the dummies, 3. the learning performance was influenced by the visual similarity of dummies and the real landing lattice.     

反复电针对慢性痛的累加治疗作用及其机制研究

本研究从基础和临床两方面观察了反复电针对慢性痛的累加治疗作用,并结合疼痛患者及慢性痛动物模型中几种神经肽的放射免疫测定及相应受体拮抗剂的药理学研究结果,探讨了产生累加效应的可能机制。结果表明,在临床脊髓损伤性痉挛患者,１００Ｈｚ穴位体表电刺激有效地缓解痉挛并有累加效应;在临床慢性痛患者,２／１５Ｈｚ变频ＴＥＮＳ刺激有效地治疗疼痛并具有累加效应。在关节炎模型大鼠,电针刺激能产生明显的镇痛并具有累加效     

Guanine nucleotide regulatory protein alterations in young Milan hypertensive strain rats

Vascular smooth muscle cell membranes from prehypertensive rats of the Milan hypertensive strain (MHS) were used to examine adenylyl cyclase activity and its regulation by guanine nucleotide regulatory proteins (G-proteins). Basal adenylyl cyclase activity was similar in MHS and Milan normontensive strain (MNS) membranes. Forsokolin (10^?4 M) produced a significantly greater stimulatory response in MHS membranes, but this was not observed with NaF (10^?2 M). Isoporterenol (10^?4 M) caused a significantly decreased stimulation of adenylyl cyclase activity in MHS membranes, while prostaglandin E₁ (10^?5 M) produced similar responses in the two strains. G_i function and GTP responses, as observed by biphasic effects of GTP on isoproterenol-stimulated membranes, were similar in both strains. The levels of G_i2α and G_qα/G₁₁α were similar in the two strains, while the levels of G_sα (44 and 42 kDa forms) and the β-subunit were significantly reduced by ～20% in MHS membranes. The α-subunit of G_i3 was dramatically reduced by ～80% in MHS membranes. The affinities of β-adrenergic receptors for the antagonist, cyanophindolol, were similar in the two strains; however, the number of β-adrenoceptors was substantially reduced in MHS membranes. These findings may be of relevance to altered vascular reactivity and transmembrane ion distribution observed in the MHS.     

Testing different 3D techniques using geometric morphometrics: Implications for cranial fluctuating asymmetry in humans

This study aimed to test the performance of 3D digitizer, CT scanner, and surface scanner in detecting cranial fluctuating asymmetry. Sets of 32 landmarks (6 in the midline and 13 bilateral) were acquired from 14 archeological crania using a 3D digitizer, and from 3D models generated from a CT scanner and surface scanner using Viewbox 4. Levels of shape variation were analyzed in MorphoJ using Procrustes analysis of variance and Principal component analysis. Intra-observer error accounted for 1.7%, 1.8%, and 4.5% of total shape variation for 3D digitizer, CT scanner, and surface scanner respectively. Fluctuating asymmetry accounted for 15%–16% of total shape variation. Variation between techniques accounted for 18% of total shape variation. We found a higher level of missing landmarks in our surface scan data than for both 3D digitizer and CT scanner data, and both 3D model-based techniques sometimes obscured taphonomic damage. All three 3D techniques are appropriate for measuring cranial fluctuating asymmetry. We advise against combining data collected with different techniques.     

Small-scale plant species turnover in a limestone grassland: the carousel model and some comments on the niche concept

Abstract. This study reports on small-scale changes in the distribution of plant species in a 2.5 m² plot of grazed, species-rich Veronica spicata - Avenula pratensis grassland on shallow, dry, nutrient-poor soil in the Great Alvar area (Stora Alvaret) of southern Öland, southeastern Sweden. Multivari-ate analysis of 0.001 m² and 0.25 m² quadrats within the plot showed that there is little floristic variation without any trend in the plot. Average species richness varied little throughout the study period from 1986 to 1991 with 1986 averages of 7.0 on 0.001m², 16.3 on 0.01 m², and 26.1 on 0.25 m². On 0.001 m²the highest species number found was 12, on 0.01 m², 27. However, cumulative species richness, i.e. species number in the first year plus new species appearing in later years (averaged over 40 quadrats) increased over the same period, on 0.001 m² from 7.0 in 1986 to 14.9 in 1991, and on 0.01 m² from 16.3 to 24.1. Cumulative frequency, i.e. number of quadrats out of 40 where a species occurred in the first year or/and in later years, increased as well; the number of cumulatively highly frequent (> 80%) species increased from 5 in 1986 to 18 in 1991. Species mobility on the scale of the small quadrats used implies both appearance and disappearance from these quadrats. Using six examples, species mobility is shown to vary individualistically, both in rate and degree. We postulate that in homogeneous, grazed, nutrient- and water-deficient environments many species can reach virtually all microsites within the plot, which we express through the idea of the ‘carousel model’. We also question the usefulness of the niche concept and re-interpret it by stating that all species of this plant community have the same habitat niche, while most of them are short-lived and have the same regeneration niche. The essential variation amongst the species is their individual ability to establish or re-establish by making use of favourable conditions appearing in microsites in an unknown, complex spatio-temporal pattern.     

Evaluating treatment effects in group sequential multivariate longitudinal studies with covariate adjustment

Jeffries et al. (2018) investigated testing for a treatment difference in the setting of a randomized clinical trial with a single outcome measured longitudinally over a series of common follow-up times while adjusting for covariates. That paper examined the null hypothesis of no difference at any follow-up time versus the alternative of a difference for at least one follow-up time. We extend those results here by considering multivariate outcome measurements, where each individual outcome is examined at common follow-up times. We consider the case where there is interest in first testing for a treatment difference in a global function of the outcomes (e.g., weighted average or sum) with subsequent interest in examining the individual outcomes, should the global function show a treatment difference. Testing is conducted for each follow-up time and may be performed in the setting of a group sequential trial. Testing procedures are developed to determine follow-up times for which a global treatment difference exists and which individual combinations of outcome and follow-up time show evidence of a difference while controlling for multiplicity in outcomes, follow-up, and interim analyses. These approaches are examined in a study evaluating the effects of tissue plasminogen activator on longitudinally obtained stroke severity measurements.     

Evaluation of several methods for estimating phylogenetic trees when substitution rates differ over nucleotide sites

Several maximum likelihood and distance matrix methods for estimating phylogenetic trees from homologous DNA sequences were compared when substitution rates at sites were assumed to follow a gamma distribution. Computer simulations were performed to estimate the probabilities that various tree estimation methods recover the true tree topology. The case of four species was considered, and a few combinations of parameters were examined. Attention was applied to discriminating among different sources of error in tree reconstruction, i.e., the inconsistency of the tree estimation method, the sampling error in the estimated tree due to limited sequence length, and the sampling error in the estimated probability due to the number of simulations being limited. Compared to the least squares method based on pairwise distance estimates, the joint likelihood analysis is found to be more robust when rate variation over sites is present but ignored and an assumption is thus violated. With limited data, the likelihood method has a much higher probability of recovering the true tree and is therefore more efficient than the least squares method. The concept of statistical consistency of a tree estimation method and its implications were explored, and it is suggested that, while the efficiency (or sampling error) of a tree estimation method is a very important property, statistical consistency of the method over a wide range of, if not all, parameter values is prerequisite.     

On-line state recognition in a yeast fed-batch culture using error vectors

The physiological states with respect to cell growth and ethanol production in a yeast fed-batch culture expressed in linguistic form could be recognized on-line by fuzzy inferencing based on error vectors. The error vector was newly defined here in a macroscopic elemental balance equation. The physiological states for cell growth and ethanol production were characterized by error vectors using many experimental data from fed-batch cultures. Fuzzy membership functions were constructed from the frequency distributions of the error vectors and state recognition was performed by fuzzy inferencing. In particular, an unusual physiological state for a yeast cultivation, in which aerobic ethanol production was accompanied by very low cell growth, could be recognized accurately. According to the results of the state recognition, an energy parameter, the P/O ratio in the metabolic reaction model was adaptively estimated, and the cell growth was successfully evaluated with the estimated P/O. (c) 1995 John Wiley & Sons, Inc.     

Enhanced early detection and enumeration of zebra mussel (Dreissena spp.) veligers using cross-polarized light microscopy

Zooplankton with calcareous skeletons are birefringent under cross-polarized light, and thus this technique can be quite useful, indeed sometimes almost essential, for the detection and enumemeration of these types of organisms in plankton samples. A simple and inexpensive application of this technique is described and illustrated with quantitative examples from research on the veligers of the zebra mussel Dreissena polymorpha (Pallas). The time required to detect veligers in plankton samples was decreased by an order of magnitude; the accuracy of counts was substantially improved (15% more than controls), and the time required for counts was greatly reduced (41% of control times). This technique is especially useful in situations in which veligers are difficult to find or see (e.g., at low densities, in samples cluttered with extraneous organisms or material) or when the investigator is inexperienced with plankton sampling and planktonic organisms. The major limitations are its inability to discriminate among various bivalve species that have planktonic larvae and the similar appearance of ostracods which also have calcareous shells. Expanded use of this technique should (1) increase our ability to use plankton sampling for the early detection of veligers during range expansion and reproductive cycles and (2) permit more accurate estimates of veliger abundance.     

Immunologic unresponsiveness of mouse spleen sensitized to allogenic tumors.

CS7BL/6 mice were sensitized with an ip injection of allogeneic P-815 mastocytoma cells. Fifteen days later the spleen cells of the tumor allosensitized mice were cultured and tested for their responsiveness to mitogens and alloantigens, and for their ability to generate cytotoxic cells in vitro. The results indicate that 15 day tumor-sensitized spleen cells are hypo-responsive in mixed lymphocyte culture (MLC) with DBA/2 or AKR as stimulating spleen cells. The cells which are hypo-responsive in MLC can proliferate in response to mitogens and they also can generate cytotoxic cells in vitro. MLC reactivity recovers in about 2–3 months which is $\text{1}\text{1}\text{2}\text{–2}\text{1}\text{2}$ months after the mice have rejected their tumors. The mechanism of MLC hypo-responsiveness was investigated. The results suggest the presence of a suppressor cell which does not appear to be a macrophage or a B-cell. The suppressor cell can be separated from the cytotoxic cell and therefore appears to be a noncytotoxic T-cell.