Analysis of spatial association between two species based on the interspecies mean crowding

Summary and Conclusion The measurement of spatial association between two species is considered on the basis of interspecies mean crowding. Two indices of overlapping, γ andC _μ, are derived as geometric and weighted arithmetic means of the same component ratios related to inter- and intraspecies mean crowdings. Both indices behave in a similar way, ranging from 1 when the distributions of two species are completely overlapped to 0 when they are completely exclusive with each other. The former is essentially identical with indices proposed byKuno (1968) andPianka (1973), and the latter is a modified form ofMorisita’s (1959)C _δ index. Indices to measure the degree of spatial correlation between species, ω andR _μ, are then derived for both kinds of overlapping indices, which vary from 1 in complete overlapping, through 0 in independent occurrence, to −1 in complete exclusion. Various kinds of interspecies association are analyzed using these indices and an extended form of the regression graph which provides a convenient way of indicating the spatial interrelation between two species as well as distribution patterns of respective species. The method presented in this paper may also be applicable to compare temporal distribution patterns between species, similarity between communities, etc. For such a wider application which includes continuous as well as discrete distributions, the interpretation of intra- and interspecies mean crowdings is not necessarily appropriate, and hence the concept of mean concentration with the symbols and for intraspecies relation and and for interspecies relation is suggested. This study was supported by Science Research Fund (No. 148041) from the Ministry of Education.     

An evolutionary analytical model of a complementary circular code simulating the protein coding genes, the 5′ and 3′ regions

The self-complementary subset ∪{AAA,TTT} with = {AAC, AAT, ACC, ATC, ATT, CAG, CTC, CTG, GAA, GAC, GAG, GAT, GCC, GGC, GGT, GTA, GTC, GTT, TAC, TTC} of 22 trinucleotides has a preferential occurrence in the frame 0 (reading frame established by the ATG start trinucleotide) of protein (coding) genes of both prokaryotes and eukaryotes. The subsets ∪{CCC} and ∪{GGG} of 21 trinucleotides have a preferential occurrence in the shifted frames 1 and 2 respectively (frame 0 shifted by one and two nucleotides respectively in the 5′-3′ direction). and are complementary to each other. The subset contains the subset which has the rarity property (6 × 10⁻⁸) to be a complementary maximal circular code with two permutated maximal circular codes and in the frames 1 and 2 respectively. is called a C³ code. A quantitative study of these three subsets in the three frames 0, 1, 2 of protein genes, and the 5′ and 3′ regions of eukaryotes, shows that their occurrence frequencies are constant functions of the trinucleotide positions in the sequences. The frequencies of in the frame 0 of protein genes are 49, 28.5 and 22.5% respectively. In contrast, the frequencies of in the 5′ and 3′ regions of eukaryotes, are independent of the frame. Indeed, the frequency of in the three frames of 5′ (respectively 3′) regions is equal to 35.5% (respectively 38%) and is greater than the frequencies and , both equal to 32.25% (respectively 31%) in the three frames. Several frequency asymmetries unexpectedly observed (e.g. the frequency difference between and in the frame 0), are related to a new property of the subset involving substitutions. An evolutionary analytical model at three parameters (p, q, t) based on an independent mixing of the 22 codons (trinucleotides in frame 0) of with equiprobability (1/22) followed by t ≈ 4 substitutions per codon according to the proportions p ≈ 0.1; q ≈ 0.1 and r = 1 − p − q ≈ 0.8 in the three codon sites respectively, retrieves the frequencies of observed in the three frames of protein genes and explains these asymmetries. Furthermore, the same model (0.1, 0.1, t) after t ≈ 22 substitutions per codon, retrieves the statistical properties observed in the three frames of the 5′ and 3′ regions. The complex behaviour of these analytical curves is totally unexpected and a priori difficult to imagine.     

Modelling the dynamics of West Nile Virus

In this work we formulate and analyze a mathematical model for the transmission of West Nile Virus (WNV) infection between vector (mosquito) and avian population. We find the Basic Reproductive Number in terms of measurable epidemiological and demographic parameters. is the threshold condition that determines the dynamics of WNV infection: if the disease fades out, and for the disease remains endemic. Using experimental and field data we estimate for several species of birds. Numerical simulations of the temporal course of the infected bird proportion show damped oscillations approaching the endemic value.     

Results of the oxygen Fick method in a closed blood circulation model including “total arteriovenous diffusive shunt of oxygen”

It is considered that arteriovenous diffusive shunts of oxygen may cause inaccuracy of the oxygen Fick method as where is the pulmonary oxygen uptake, is the cardiac output, and CaO₂ and CvO₂ are the arterial and venous oxygen contents, respectively. A simple circulation model, including the whole circulation with nine well-mixed compartments (C1, ... C9), is constructed: the is assigned as constant as 6000 ml min⁻¹; the blood portions of 60 ml move at an interval of 600 ms. C1 and C2 compartments, each having 60 ml volume, represent the blood of pulmonary microcirculation, C3 represents the arterial blood with a volume of 1500 ml, C4, ..., C8, each also having a volume of 60 ml, represent the blood of peripheral microcirculation, whereas C9 represents the venous blood with a volume of 3000 ml. The pulmonary oxygen uptake , related to C1 and C2, the oxygen release , related to C4,...,C8, as well as a “total arteriovenous diffusive shunt of oxygen” , from the arterial blood (C3) to the venous blood (C9), are calculated simultaneously. The alveolar gas has a constant oxygen partial pressure, and the pulmonary diffusion capacity is also constant; similar to modeling the pulmonry, oxygen diffusion, constant partial oxygen pressures for all peripheral tissues as well as constant diffusion capacities for all peripheral oxygen diffusion are also assigned. The diffusion capacities for the (between C3 and C9) are arbitrarily assigned. The Fick method gives incorrect results depending on the total arteriovenous diffusive shunt of oxygen . But the mechanism determining the magnitude of remains unclear.     

Evidence for four nonallelic structural genes for the γ chain of human fetal hemoglobin

An abnormal human fetal hemoglobin not only may be either a^Gγ- or an^Aγ-chain variant but also may be present in a different proportion of the total fetal hemoglobin.^Gγ-Chain variants contribute either about one-fourth or one-eighth to the total production of HbF in the heterozygote, whereas the^Aγ-chain variants approximate either one-eighth or one-sixteenth of the total HbF. These observations may indicate the presence of four nonallelic Hb_γ structural genes (termed ) which produce γ chains in an approximate ratio of 4 : 2 : 2 : 1. HbF Malta I is considered to be the product of a mutant of the locus, an undefined HbF_x that of the locus, HbF Hull and HbF Jamaica products of mutated loci, and the newly discovered HbF Malta II a mutant of the gene. This work was supported in part by grants HL-05168 and HL-02558 from the National Institutes of Health, U.S. Public Health Service.     

Water uptake by barley roots as affected by the osmotic and matric potential in the rhizosphere

Summary The water uptake rates of roots in saline soils are depressed by the simultaneously decreasing matric and osmotic water potentials in the soil surrounding the roots (rhizospheric soil). Unfortunately there are no reliable tools available for direct measurements of the effect of decreasing water potentials in the rhizospheric soil on the uptake rate of soil water by roots. This paper presents some results of a vegetation technique for studying the effect of different combinations of osmotic and matric water potentials in the rhizospheric soil on the water uptake rates of barley roots. Water uptake rates were reduced to a greater extent by decreasing soil matric water potentials than by decreasing soil osmotic water potentials. According to the results of this experiment, there was no relationship between the total soil water potential of a sandy soil and the water uptake rates when the roots were exposed to different combinations of and .     

Carbon membrane-aerated biofilm reactor for synthetic wastewater treatment

A carbon membrane-aerated biofilm reactor (CMABR) was developed to treat synthetic wastewater. Such membrane exhibited a high degree of adhesion and good permeability. Continuous experiments showed that COD and -N removal efficiency were 90 ± 2 and 92 ± 4% at removal rates of 35.6 ± 3.8 g COD/m² per day and 9.3 ± 0.6 g -N/m² per day, respectively. After 108 days, effluent total nitrogen (TN) kept at 35 ± 4 mg/L when influent -N increased to 144–164 mg/L and removal efficiency of TN reached 78 ± 3%. Furthermore, Stoichiometric analysis revealed that 70–90% of oxygen supplied was consumed by nitrifier. Scanning electron microscopic (SEM) images and component analysis of penetrating fluid revealed that extracellular polymeric substance (EPS) adhered to pore and that alkaline washing was an effective method to remove them. The study demonstrated that carbon membrane could be used as effective gas-permeable membrane in MABR for wastewater treatment.     

Use of the force-velocity test to determine the optimal braking force for a sprint exercise on a friction-loaded cycle ergometer

A group of 15 untrained male subjects pedalled on a friction-loaded cycle ergometer as fast as possible for 5–7 s to reach the maximal velocity (V{immax}) against different braking forces (F _B). Power was averaged during a complete crank rotation by adding the power dissipated againstF _B to the power necessary to accelerate the flywheel. For each sprint, determinations were made of peak power output ( ) power output attained atV _max ( ) calculated as the product ofV _max andF _B and the work performed to reachV _max expressed in mean power output ( ). The relationships between these parameters andF _B were examined. A biopsy taken from the vastus lateralis muscle and tomodensitometric radiographs of both thighs were taken at rest to identify muscle metabolic and morphometric properties. The value was similar for allF _B. Therefore, the average of values was defined as corrected maximal power ( ). This value was 11 higher than the maximal power output uncorrected for the acceleration. Whereas the determination did not require high loads, the highest value ( ) was produced when loading was heavy, as evidenced by the -F _B parabolic relationship. For each subject, the braking force ( ) giving was defined as optimal. The , equal to 0.844 (SD 0.108) N · kg⁻¹ bodymass, was related to thigh muscle area (r = 0.78,P < 0.05). The maximal velocity ( ) reached against this force seemed to be related more to intrinsic fibre properties (% fast twitch b fibre area and adenylate kinase activity). Thus, from the determination, it is suggested that it should be possible to predict the conditions for optimal exercise on a cycle ergometer.     

Energy metabolism and ATP free-energy change of the intertidal wormSipunculus nudus below a critical temperature

The intertidal wormSipunculus nudus was exposed to various temperatures for an analysis of the integrated changes in energy and acid-base status. Animals were incubated in sea water or maintained for up to 8 days at 4 and 0°C while dwelling in the sediment. Cannulation of the animals prior to experimentation allowed the analysis of blood gas parameters ( , and pH). fell to 0 torr within 8 days at 0°C. A simultaneous reduction of ventilatory activity was derived from measurements of the pattern of coelomic fluid pressure changes associated with ventilatory movements. The increase in and an onset of anaerobic metabolism, indicated by the accumulation of end products like acetate and propionate both in the coelomic fluid and the body wall musculature, led to the development of a progressive acidosis and a deviation from the alphastat regulation of intracellular pH seen in unburied animals. The drop in intracellular pH together with the depletion of the adenylates and the phosphagen, phospho-l-arginine, reflect a significant decrease in the Gibb's free-energy change of ATP hydrolysis. These changes are interpreted to indicate lethal cold injuries, because recovery was not possible when the animals were returned to 12°C after more than 2 days of exposure to 0°C. A low critical temperature indicating the onset of cold-induced anaerobiosis is concluded to exist below 4°C owing to the insufficient response of the ventilatory system to the developing hypoxia.     

Are male rhesus monkeys more aggressive than females?

The justification for the “generalization that primate males are more aggressive than females” (Fedigan & Baxter, 1984) was tested in a troop of 24 captive rhesus monkeys. Males (N=9) were more dominant than females (N=15), i.e., they had more subordinate partners ( _m=17.0 vs. _f=6.6;p<0.01); hence, their aggression rate was higher ( _m=77.6 vs. _m=38.1;p<0.05). However, adjusting the rate of aggression according to the number of subordinate targets revealed no gender difference and males directed numbers of aggressive acts against individual subordinate partners that were not higher than those of females ( _m=4.4 vs. _f=5.4;p>0.1). It was concluded that aggressiveness is an individual attribute that is (1) independent of dominance status, and (2) independent of sex.     

(H)NCAHA and (H)CANNH experiments for the determination of vicinal coupling constants related to the ϕ-torsion angle

Summary A set of three-dimensional triple-resonance experiments is described which provide , , and coupling constants. The pulse sequences generate E.COSY-like multiplet patterns and comprise a magnetization transfer from the amide proton to the α-proton or vice versa via the directly bound heteronuclei. For residues with the ¹H^α spin resonating close to the H₂O signal, a modified HNCA experiment can be employed to measure the vicinal ¹H^N,¹H^α couplings. Ambiguities associated with the conversion of values into ϕ-angle constraints for protein structure determination can be resolved with the knowledge of the heteronuclear ³J-couplings. In favourable cases, stereospecific assignments of glycine α-protons can be obtained by employing the experiments described here in combination with NOE data. The methods are applied to flavodoxin from Desulfovibrio vulgaris.     

Ammonium-limited growth and uptake by Oscillatoria agardhii in chemostat cultures

Growth of Oscillatoria agardhil was studied in ammonium-limited chemostat cultures, at various dilution rates (=growth rates, μ). The uptake kinetics for ammonium of nitrogen (ammonium or nitrate)-limited chemostat cultures also was investigated. The kinetics of ammonium-limited growth could be adequately described by both the Monod and Droop equations, and were closely similar to the nitrate-limited growth kinetics of this species. The uptake kinetics for ammonium showed similarities as well as differences with the uptake kinetics for nitrate. The similarities were apparent in the uptake capacity values for ammonium and nitrate , which were identical, high and independent of μ. The differences were to be found in the half-saturation constants for ammonium uptake and nitrate uptake , the former being hardly influenced by μ. A consitutive, high affinity, system is likely to operate in the uptake and assimilation of ammonium by nitrogen-limited O. agardhii. The use of ammonium uptake parameters in studies of growth-limiting factors in nature can provide information as to whether a nitrogen-limitation prevails in natural habitats of this species.     

Stochastic models for chemical reactions: I. Theory of the unimolecular reaction process

A stochastic model for the basic unimolecular chemical reaction is derived. This model provides a mathematical basis, altogether missing in the current kinetic theory, for the analysis of inherent random fluctuations about the strict concentration-time course prescribed by the existing deterministic theory. Limits on the extent of the predicted inherent variability are obtained and compared with those usually expected purely on the basis of random experimental errors of extraneous origin (not associated with the mechanism of reaction). The results support the extrapolation to chemical systems of a principle of statistical inaccuracy for physical systems which has been called by E. Schroedinger “the Law of Physics.”     

The dissociation and separation of bovine adenohypophysial cells

Bovine adenohypophysial tissue was dissociated by sequential enzymatic incubation in a continuous flow system. Dispersed cells separated into discrete fractions after centrifugation in isopycnic bovine serum albumin gradients. The dispersed and separated cells were prepared for microscopic identification and differential counts by centrifugal cytology. Radioimmunoassays for LH, FSH, TSH, and Prl were used to corroborate the differential counts and determine the homogeneity of the fractions. The thyrotrophs banded at an average density ( ) of 1.0417, the FSH-secretory cells at , the LH-secretory cells at , and the Prl-secretory cells at . A 7–16 fold enrichment of different cell populations was possible. In bovine hypophyses each hormone appears to be formed by specific cells: the average TSH concentrations of the thyrotrophs were 5.1 pg/cell and the average LH and FSH concentrations were 4.7 and 4.9 pg/cell for LH-and FSH-secreting cells, respectively. The average Prl concentration was 4.9 pg/cell for Prl-secreting cells.     

The\dot V_A /\dot Q resolution of inert gas dataresolution of inert gas data

The non-uniqueness of distributions satisfying inert gas retention data without error is studied. The ability of such data to resolve blood flows at particular values is discussed through the application of linear programming and Backus-Gilbert theory. It is shown that the resolution deteriorates away from the extremes of low and high .     

Allometric relations,metabolism and heart conductance in clusters of honey bees at cool temperatures

Summary Clusters of honey bees,Apis mellifera carnica, showed a clear dependence of oxygen consumption and heat conductance on bee cluster mass (between 5 g and 1.2 kg) when exposed to a cold temperature (2°C) overnight. As the bee cluster mass was increased, total cluster metabolism increased. Mass-specific oxygen consumption, , decreased with increasing mass following the relation: = 22.69BW ^−0.479 (Fig. 1). Larger clusters of bees had lower heat conductance (i.e., better insulation) than the smaller groups (Fig. 4). The mechanisms of adaptation and adjustment to cold temperature in bee clusters are discussed and compared with those of mammals and birds.     

Association between ADAM33 S2 and ST+4 polymorphisms and susceptibility to asthma: A meta-analysis

Objective

The aim of this study was to determine whether ADAM33 (a disintegrin and metalloproteinase domain 33) polymorphisms confer susceptibility to asthma in different populations.

Methods

We performed a meta-analysis on the association between the ADAM33 S2, ST+4, F+1, S1, and V4 polymorphisms and asthma.

Results

Thirteen studies in ten reports, which included 4942 patients and 7933 controls, were available for the meta-analysis. Meta-analysis stratified by ethnicity indicated an association between the ADAM33 S2 2 allele and asthma in Europeans (OR = 0.912, 95% CI = 0.851–0.977, p = 0.009). Meta-analysis revealed an association between asthma and the ADAM33 ST+4 2 allele (OR = 0.783, 95% CI = 0.762–0.999, p = 0.048). Stratification by ethnicity indicated an association between the ADAM33 ST+4 polymorphism and asthma in Asians. Stratification by age indicated an association between the ADAM33 ST+4 2 allele and asthma in adults (OR = 0.863, 95% CI = 0.782–0.964, p = 0.008). However, no association was found between asthma and the ADAM33 F+1, S1, and V4 polymorphisms.

Conclusions

This meta-analysis demonstrates that the ADAM33 S2 polymorphism confers susceptibility to asthma in Europeans and the ADAM33 ST+4 polymorphism is associated with asthma in Asians and adults.     

The height and weight of Kuwaiti pre-school children

This paper consider the effect of age-grouping on the distribution of two variables, namely, height and weight of pre-school children subject to growth. Assuming straight line regression models for the dependence of expected values as well as variances and covariance of height and weight was investigated by Ehrenberg's law-like model. Ehrenberg's law-like relationship between height and weight, Log , was applied to Kuwaiti children under 7 years of age. It was found that the relationship log was a good fit for Kuwaiti boys and girls except for children under 1 year where the results were significantly different from the expected value     

Association between IL-4 polymorphism and acute rejection of solid organ allograft: A meta-analysis

Background

Cytokines have been implicated in the acute rejection of solid organ transplantation. Many studies have investigated the association between recipient or donor IL-4 polymorphism and acute rejection, with different studies reporting inconclusive results.

Methods

We searched PUBMED and EMBASE until June 2012 to identify eligible studies investigating the association between IL-4 polymorphism with acute rejection after solid organ transplantation. Statistical analysis was performed using STATA10.0.

Results

A total of 12 studies were included. Pooled ORs suggested 1) no significant association was detected between recipient or donor IL-4 − 590C/T polymorphism and acute rejection of solid allograft; 2) no significant association was detected between recipient IL-4 − 33C/T polymorphism and acute rejection of solid allograft; 3) when stratified by transplantation type, IL-4 − 590C/T polymorphism was associated with acute rejection of liver transplantation (T/T + C/T vs. C/C: OR = 0.36, 95%CI = 0.14–0.90); 4) significantly decreased risk of acute rejection was detected in recipient IL-4 − 590*T-negative/donor T-positive genotype pairs than all other recipient–donor IL-4 − 590T/C pairs (OR = 0.14, 95%CI = 0.03–0.66).

Conclusions

Our meta-analysis suggested that recipient IL-4 − 590C/T polymorphism was associated with acute rejection of liver transplantation, but nor renal or heart transplantation. It was also suggested that combined recipient IL-4 − 590*T-negative/donor T-positive genotype may suffer decreased risk of acute rejection of solid allograft. Further well-designed studies with larger sample size were required to verify our findings, with focus on the association of IL-4 polymorphism with acute rejection in patients with liver transplantation and studies investigating combined recipient–donor genotype.     

Some results in graph theory and their application to abstract relational biology

It has been shown in earlier work that one approach to what Rashevsky has called “abstract biology” is through the study of the class of ( )-systems that can be formed in an arbitrary subcategory of the category of sets. The concept of the ( )-system, however, depends on the availability of mappings that contain other mappings in their range. It is shown that, by introducing an appropriate measure for this property, the problem of characterizing those categories suitable for a rich theory of ( )-systems reduces to a problem familiar from the general theory of graphs. Some new results in these directions are obtained, and it is then shown that any category with mappings that possess properties we might expect to hold in the physical world will also admit a rich theory of ( )-systems. In particular, it is shown that a sufficiently large family of mappings drawn at random from such a category will with overwhelming probability contain an ( )-system. This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command, under Grant No. AF-AFOSR-9-63.