How Carefully Executed Network Theory Informs Invasion Ecology

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COMPUTER AIDED BIOMECHANICAL FILM ANALYSIS PROGRAM

It is a very big problem to analyzing high s eed films that researchers and coaches had made their athletes. Now we know a lot of very good filmanalyzing computer programs that made anywhere but these programs many times is on1 for research work not to sell. Big software houses (f.e. Microsoft, Borland, ...) have not any interesting this very special and narrow market. We accepted this but we need these pro rams. We decided to make ourselves a new program in 1991 and we think that we never will finish developing because new methods and aspects we will see tomorrow again. The program was written Turbo Pascal 6.0. It needs an IBM compatible XT or AT computer with 640 Kb RAM and minimum one flopp driver. The program automatically detected the screen driver and it has six main menu points. The first main menu point is DATA MANAGEMENT. We have choice to read data from a digitizer, from keyboard, from files. In this point we can see data on the screen or can print them (with velocities and accelerations). Here we can calculate the center of gravities of body segments and the total center of gravities of human body and weights of body parts by Dempster and Walton. The second main menu points is the graphics on the screen and on the plotter. We have to visualise the body as a little figure and any points of the human body that we digitalized before. The third point we can calculate some smoothing procedures. The fourth main menu point we have to compare two curves and the program calculate the difference between this two curves. The fifth point we have to calculate some angels and the velocities and accelerations of these angels. The sixth point program calculates some forces and torques if we know the mass of any body parts ( by Dempster)

Continuous coexistence or discrete species? A new review of an old question

Question: Is the coexistence of a continuum of species or ecological types possible in real-world communities? Or should one expect distinctly different species? Mathematical methods: We study whether the coexistence of species in a continuum of ecological types is (a) dynamically stable (against changes in population densities) and (b) structurally robust (against changes in population dynamics). Since most of the reviewed investigations are based on Lotka-Volterra models, we carefully explain which of the presented conclusions are model-independent. mathematical conclusions: Seemingly plausible models with dynamically stable continuous- coexistence solutions do exist. However, these models either depend on biologically unrealistic mathematical assumptions (e.g. non-differentiable ingredient functions) or are structurally unstable (i.e. destroyable by arbitrarily small modifications to those ingredient functions). The dynamical stability of a continuous-coexistence solution, if it exists, requires positive definiteness of the model's competition kernel. Biological conclusions: While the classical expectation of fixed limits to similarity is mathematically naive, the fundamental discreteness of species is a natural consequence of the basic structure of ecological interactio

THE CHANGING OF ROWING TECHNIQUE AS A FUNCTION OF EXERTION

In our paper we examine the effect of the added exertion on the changing of technique in the rowing motion under laboratory conditions, usin4 an ergometer. The Hungarian National Junior team of four helped us at the examinations, which consisted of an anthropometrical measurement and five steps of exertion on the rowing ergometer, where the spreading of the motions during the exertion period was determined by a computer (SELSPOT system), meanwhile the level of tiredness by the measurement of pulse and the acidity of blood in the intervals between these periods. The comparison of the levels of tiredness shown by the physiological characteristics and of the changings in the motion of rowing can help us not only in the detection of unique errors, but also of some constant technical ones, which are dealt with thoroughly in my lecture

Let's Train More Theoretical Ecologists - Here Is Why

A tangled web of vicious circles, driven by cultural issues, has prevented ecology from growing strong theoretical roots. Now this hinders development of effective conservation policies. To overcome these barriers in view of urgent societal needs, we propose a global network of postgraduate theoretical training programs

Distinct ErbB2 receptor populations differentially interact with beta1 integrin in breast cancer cell models

ERBB2 is a member of the ERBB family of tyrosine kinase receptors that plays a major role in breast cancer progression. Located at the plasma membrane, ERBB2 forms large clusters in spite of the presence of growth factors. Beta1 integrin, membrane receptor of extracellular matrix proteins, regulates adhesion, migration and invasiveness of breast cancer cells. Physical interaction between beta1 integrin and ERBB2 has been suggested although published data are contradictory. The aim of the present work was to study the interaction between ERBB2 and beta1 integrin in different scenarios of expression and activation. We determined that beta1 integrin and ERBB2 colocalization is dependent on the expression level of both receptors exclusively in adherent cells. In suspension cells, lack of focal adhesions leave integrins free to diffuse on the plasma membrane and interact with ERBB2 even at low expression levels of both receptors. In adherent cells, high expression of beta1 integrin leaves unbound receptors outside focal complexes that diffuse within the plasma membrane and interact with ERBB2 membrane domains. Superresolution imaging showed the existence of two distinct populations of ERBB2: a major population located in large clusters and a minor population outside these structures. Upon ERBB2 overexpression, receptors outside large clusters can freely diffuse at the membrane and interact with integrins. These results reveal how expression levels of beta1 integrin and ERBB2 determine their frequency of colocalization and show that extracellular matrix proteins shape membrane clusters distribution, regulating ERBB2 and beta1 integrin activity in breast cancer cells.Instituto de Investigaciones Bioquímicas de La Plat

Catalytic mechanism of alpha-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling.

Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason-Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the alpha-phosphate site. Phosphorus-31 NMR spectroscopy (31P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue alpha,beta-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme-product complex structure

O055. Headache and psychopathological aspects in Gilles de la Tourette Sindrome:a comparison between paediatric and adult patients

Only few studies have analyzed the occurrence of headache in patients with Gilles de la Tourette syndrome (GTS) [1–3]. The aim of this study was to compare the prevalence and characteristics of headache in paediatric and adult patients with GTS and the relationship of headache with tic severity, psychiatric comorbidities and quality of life

Transposase-DNA complex structures reveal mechanisms for conjugative transposition of antibiotic resistance

Conjugative transposition drives the emergence of multidrug resistance in diverse bacterial pathogens, yet the mechanisms are poorly characterized. The Tn1549 conjugative transposon propagates resistance to the antibiotic vancomycin used for severe drug-resistant infections. Here, we present four high-resolution structures of the conserved Y-transposase of Tn1549 complexed with circular transposon DNA intermediates. The structures reveal individual transposition steps and explain how specific DNA distortion and cleavage mechanisms enable DNA strand exchange with an absolute minimum homology requirement. This appears to uniquely allow Tn916-like conjugative transposons to bypass DNA homology and insert into diverse genomic sites, expanding gene transfer. We further uncover a structural regulatory mechanism that prevents premature cleavage of the transposon DNA before a suitable target DNA is found and generate a peptide antagonist that interferes with the transposase-DNA structure to block transposition. Our results reveal mechanistic principles of conjugative transposition that could help control the spread of antibiotic resistance genes

Distinct ErbB2 receptor populations differentially interact with beta1 integrin in breast cancer cell models

ERBB2 is a member of the ERBB family of tyrosine kinase receptors that plays a major role in breast cancer progression. Located at the plasma membrane, ERBB2 forms large clusters in spite of the presence of growth factors. Beta1 integrin, membrane receptor of extracellular matrix proteins, regulates adhesion, migration and invasiveness of breast cancer cells. Physical interaction between beta1 integrin and ERBB2 has been suggested although published data are contradictory. The aim of the present work was to study the interaction between ERBB2 and beta1 integrin in different scenarios of expression and activation. We determined that beta1 integrin and ERBB2 colocalization is dependent on the expression level of both receptors exclusively in adherent cells. In suspension cells, lack of focal adhesions leave integrins free to diffuse on the plasma membrane and interact with ERBB2 even at low expression levels of both receptors. In adherent cells, high expression of beta1 integrin leaves unbound receptors outside focal complexes that diffuse within the plasma membrane and interact with ERBB2 membrane domains. Superresolution imaging showed the existence of two distinct populations of ERBB2: a major population located in large clusters and a minor population outside these structures. Upon ERBB2 overexpression, receptors outside large clusters can freely diffuse at the membrane and interact with integrins. These results reveal how expression levels of beta1 integrin and ERBB2 determine their frequency of colocalization and show that extracellular matrix proteins shape membrane clusters distribution, regulating ERBB2 and beta1 integrin activity in breast cancer cells.Instituto de Investigaciones Bioquímicas de La Plat