NN interaction in a Goldstone boson exchange model

Adiabatic nucleon-nucleon potentials are calculated in a six-quark nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between quarks. Calculations are performed both in a cluster model and a molecular orbital basis, through coupled channels. In both cases the potentials present an important hard core at short distances, explained through the dominance of the [51]_{FS} configuration, but do not exhibit an attractive pocket. We add a scalar meson exchange interaction and show how it can account for some middle-range attraction.Comment: 32 pages with 12 eps figures incorporated, RevTeX. Final version published in PR

The rise (and rise) of vertical studentification: Exploring the drivers of studentification in Australia

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The d' dibaryon in the quark-delocalization, color-screening model

We study the questions of the existence and mass of the proposed $d' (IJ^P=00^-)$ dibaryon in the quark-delocalization, color-screening model (QDCSM). The transformation between physical and symmetry bases has been extended to the cases beyond the SU(2) orbital symmetry. Using parameters fixed by baryon properties and $NN$ scattering, we find a mild attraction in the $IJ^P=00^-$ channel, but it is not strong enough to form a deeply bound state as proposed for the $d'$ state. Nor does the (isospin) I=2 N$\Delta$ configuration have a deeply bound state. These results show that if a narrow dibaryon $d'$ state does exist, it must have a more complicated structure.Comment: 12 pp. latex, no figs., 2 tables, additional refs., Report-no was adde

Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Phenomenological study of hadron interaction models

We present a phenomenological study of three models with different effective degrees of freedom: a Goldstone Boson Exchange (GBE) model which is based on quark-meson couplings, the quark delocalization, color screening model (QDCSM) which is based on quark-gluon couplings with delocalized quark wavefunctions, and the Fujiwara-Nijmegen (FN) mixed model which includes both quark-meson and quark-gluon couplings. We find that for roughly two-thirds of 64 states consisting of pairs of octet and decuplet baryons, the three models predict similar effective baryon-baryon interactions. This suggests that the three very different models, based on different effective degrees of freedom, are nonetheless all compatible with respect to baryon spectra and baryon-baryon interactions. We also discuss the differences between the three models and their separate characteristics.Comment: 30 pages latex, 7 tables, 12 figs; submitted to Phys. Rev.

Automated Analysis of Craniofacial Morphology Using Magnetic Resonance Images

Quantitative analysis of craniofacial morphology is of interest to scholars working in a wide variety of disciplines, such as anthropology, developmental biology, and medicine. T1-weighted (anatomical) magnetic resonance images (MRI) provide excellent contrast between soft tissues. Given its three-dimensional nature, MRI represents an ideal imaging modality for the analysis of craniofacial structure in living individuals. Here we describe how T1-weighted MR images, acquired to examine brain anatomy, can also be used to analyze facial features. Using a sample of typically developing adolescents from the Saguenay Youth Study (N = 597; 292 male, 305 female, ages: 12 to 18 years), we quantified inter-individual variations in craniofacial structure in two ways. First, we adapted existing nonlinear registration-based morphological techniques to generate iteratively a group-wise population average of craniofacial features. The nonlinear transformations were used to map the craniofacial structure of each individual to the population average. Using voxel-wise measures of expansion and contraction, we then examined the effects of sex and age on inter-individual variations in facial features. Second, we employed a landmark-based approach to quantify variations in face surfaces. This approach involves: (a) placing 56 landmarks (forehead, nose, lips, jaw-line, cheekbones, and eyes) on a surface representation of the MRI-based group average; (b) warping the landmarks to the individual faces using the inverse nonlinear transformation estimated for each person; and (3) using a principal components analysis (PCA) of the warped landmarks to identify facial features (i.e. clusters of landmarks) that vary in our sample in a correlated fashion. As with the voxel-wise analysis of the deformation fields, we examined the effects of sex and age on the PCA-derived spatial relationships between facial features. Both methods demonstrated significant sexual dimorphism in craniofacial structure in areas such as the chin, mandible, lips, and nose

2005 Wild Blueberry Project Reports

The 2005 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Evaluation of Emerging Disinfections Technologies for Wild Blueberry Processing 1A. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers. 2. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers 3. Wild blueberries and Arterial Functional Properties 4. Practical Microbial Control Approach and Antimicrobial Properties Study for Wild Blueberries 5. Wild Blueberries Reduce Risks for Cardiovascular Disease –No Report at this time, data is still under analysis. 6. Irrigation Water Use in Wild Blueberry Production 7. Control Tactics for Blueberry Pest Insects, 2005 8. Integrated Pest Management (IPM) strategies, 2005 9. Control Tactics for Blueberry Pest Insects, 2005 10. The Effect of Fungicides and Cultural Treatments on Monilinia Blight, Yield and Post-Harvest Disease in Wild Blueberries 11. Effect of Soil pH on Nutrient Uptake 12. Effect of Manganese on Growth and Yield of Wild Blueberry 13. Raising Foliar Nitrogen by Application of CoRoN 14. Effects of Summer Foliar Fertilization to Increase Branch Length and Flower Bud Formation in the Prune Year 15. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Field Cover Program Base 16. Evaluation of Fall Applications of Tribenuron Methyl for Bunchberry Control in Wild Blueberries 17. Evaluation of spot treatments of Tribenuron Methyl for weed control in Wild Blueberries 18. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 19. Assessment of Evitol and Kerb for Sedge Control in Wild Blueberrie

2006 Lowbush Blueberry Project Reports

The 2006 edition of the Lowbush Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Evaluation of Emerging Disinfection Technologies for Wild Blueberry Processing 2. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers 3. Infestation Detection using NIRS 4. Mechanism of Action through which Wild Blueberries affect Arterial Functional Properties in Normotensive and Spontaneously Hypertensive Rats 5. Practical Microbial Control Approach for Wild Blueberries and their Antimicrobial Property 6. Wild Blueberry Consumption and Risks for Cardiovascular Disease 7. Irrigation Water use in Wild Blueberry Production 8. Control Tactics for Blueberry Pest Insects & Program Base 9. Integrated Pest Management (IPM) Strategies 10. Biology and Ecology of Blueberry Insect Pests, 2006 11. Research on Wild Blueberry Diseases for 2006-2007 12. Effect of Soil pH on Nutrient Uptake 13. Effect of Manganese on Growth and Yield of Wild Blueberry 14. Effects of Summer Foliar Fertilization to Increase Branch Length and Flower Bud Formation in the Prune Year 15. Effects of Phosphite Foliar Fertilizers on disease control and fruit set of wild blueberry 16. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries 17. Evaluation of Fall Applications of Tribenuron Methyl for Bunchberry Control in Wild Blueberries 18. Evaluation of spot treatments of Tribenuron Methyl, Ultim and Roundup for weed control in Wild Blueberries 19. Blueberry Extension Education Program 20. Cultural Weed Management Using p

A fresh look at the evolution and diversification of photochemical reaction centers

In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments. I show, for example, that the protein folds at the C-terminus of the D1 and D2 subunits of Photosystem II, which are essential for the coordination of the water-oxidizing complex, were already in place in the most ancestral Type II reaction center subunit. I then evaluate the evolution of reaction centers in the context of the rise and expansion of the different groups of bacteria based on recent large-scale phylogenetic analyses. I find that the Heliobacteriaceae family of Firmicutes appears to be the earliest branching of the known groups of phototrophic bacteria; however, the origin of photochemical reaction centers and chlorophyll synthesis cannot be placed in this group. Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria. Finally, I argue that the discrepancies among the phylogenies of the reaction center proteins, chlorophyll synthesis enzymes, and the species tree of bacteria are best explained if both types of photochemical reaction centers evolved before the diversification of the known phyla of phototrophic bacteria. The primordial phototrophic ancestor must have had both Type I and Type II reaction centers