Classical and quantum quasi-free position dependent mass; P\"oschl-Teller and ordering-ambiguity

We argue that the classical and quantum mechanical correspondence may play a basic role in the fixation of the ordering-ambiguity parameters. We use quasi-free position-dependent masses in the classical and quantum frameworks. The effective P\"oschl-Teller model is used as a manifested reference potential to elaborate on the reliability of the ordering-ambiguity parameters available in the literature.Comment: 10 page

The interaction between ectomycorrhizal fungi and growth promoting bacteria in plant development from in-vitro to the field

There is currently an array of biotechnological tools which may positively influence plant development and establishment. Symbiosis with ectomycorrhizal fungi is known to improve plant health by increasing nutrient and water uptake and alleviating environmental stresses. Some rhizosphere bacteria are also proven to act as plant stimulating agents, health managers and growth promoters. The use of a combined inoculum using both microorganisms has great potential in forestry. Nevertheless, the interaction between fungi and bacteria is highly specific and bacteria are known not only to enhance fungal growth (mycorrhiza promoting bacteria), but also to strongly inhibit it. It is therefore important to evaluate the compatibility between ectomycorrhizal fungi and bacteria and to determine the impact of such combination in plant development when aiming at the use of optimized microbial inoculum for enhancing plant growth. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with ectomycorrhizal fungi, from in-vitro tests to a nursery stage followed by transplantation to the field. Approximately 5000 seedlings were used in these experiments comprising Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal. The first sampling was made before field transplantation. Results showed that the combined use of fungi-bacteria inoculum significantly influenced plant growth and its effect was different from that of each individual microbial partner, emphasizing the strong interaction between microorganisms

Impact of bacterial inoculation of Quercus suber on mycorrhization by Suillus species at early stages of tree development

Portugal accounts for approximately 50% of the world cork production. Quercus suber is the second most abundant tree in Continental Portugal, covering currently 737 thousand hectares and representing 23% of the forest area. This species is of paramount importance to the country both ecologically and economically. As many other forest species, Q. suber forms symbiotic associations with ectomycorrhizal (ECM) fungi with the hyphae acting as fine extensions of the plant root system allowing it to capture water and nutrients in exchange for photosynthetic carbohydrates. The use of bacteria as inoculum also has great potential in forestry, whether through their capability to act as plant growth promoters (PGPB) or/and as mycohhizal helper bacteria (MHB). The latter have a direct impact in promoting fungal symbiosis and could possibly represent the third link in the mycorrhizal partnership. However, the association between all vertices of the triangle (plant-fungi-bacteria) is highly specific and needs to be further explored when aiming at the use of microbial inocula in the tuning of mycorrhization at nursery stage. The aim of this work was to study the impact of inoculating Q. suber with a fungus belonging to the genus Suillus and a bacterial strain belonging to the genus Mesorhizobium, proven to be PGPB in preliminary studies. The experiment was conducted in a forest nursery in Amarante. After 9 months, the impact of inoculating with each microorganism individually was compared to that of the use of the combined inoculum. Biometric parameters were determined (shoot height, primary and secondary root length, shoot and root dry weight) and mycorrhizal parameters were assessed (percentage of ECM colonisation and expansion rate). The presence of selected phytohormones was also determined by HPLC. Overall, inoculated plants had a superior performance than the non-inoculated controls, in the majority of the parameters studied. The use of the combined inoculum was more successful than any other treatment in promoting shoot height and led to the highest concentration of indoleacetic acid (IAA). The results obtained suggest that the use of bacteria in the mycorrhization of Q. suber may positively affect plant in its early stage of development

Combining ectomycorrhizal fungi and bacteria: a powerful tool to improve tree performance

Ectomycorrhizal fungi are ubiquitous to forest soils and the symbiosis between these microorganisms and plants roots is known to be essential for tree establishment and development, especially in areas of poor soil. Studies have also shown that some rhizosphere bacteria may act as plant stimulating agents and growth promoters. Additionally, bacteria and fungi strongly interact and therefore the analysis of the triangle plant-fungi-bacteria is a vital approach when aiming at the use of microbial inocula to enhance plant performance. To obtain a synergistic combination between microorganisms, a thorough selection is required since bacteria may strongly inhibit fungal growth, and vice versa, incurring in the risk of failed inoculum. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with selected ectomycorrhizal fungi. In vitro tests were performed to assess the dynamic of co-culturing both microorganisms. The inoculum was applied at nursery stage and saplings were then transplanted into the field. Approximately 5000 seedlings were used in this experiment comprising the following species: Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal: Mindelo, Santo Tirso, Vila do Conde and Proença-a-Nova. Samples were taken at the end of nursery phase and 8 months after transplantation. Biometric and mycorrhizal parameters were analyzed and the persistence of the inoculated strains was evaluated. The presence of selected phytohormones was also determined. Results showed that the combined use of fungi-bacteria inoculum can be more effective than the use of each individual microbial partner. The use of ectomycorrhizal fungi and bacteria has great potential in forestry as a biotechnological tool to produce high performance plants at nursery stage and in the field

Inflammatory fibroid polyp of the ileum presenting with small bowel obstruction in an adult patient: a case report

<p>Abstract</p> <p>Introduction</p> <p>Inflammatory fibroid polyps are rare benign tumors of the gastrointestinal tract with the gastric antrum being the most common site, followed by the ileum. Histogenesis is still unknown and controversial. Inflammatory fibroid polyps are one of the rare benign conditions leading to intestinal obstruction in adults.</p> <p>Case presentation</p> <p>A 54-year-old Caucasian man presented with acute abdomen pain and a two month history of intermittent cramping and lower abdominal pain. Computed tomography imaging demonstrated a partial intestinal obstruction in the location of the terminal ileum. An ileo-ileal intussusception due to a mass lesion 15 cm proximal to the caecum was found on exploratory laparotomy. Intussusception was spontaneously reduced during exploration and a wedge resection was performed to the affected bowel segment. Histopathologic examination showed the mass to be an inflammatory fibroid polyp.</p> <p>Conclusion</p> <p>Although inflammatory fibroid polyps are rare and benign, in the case of intestinal obstruction the only solution is a surgical approach.</p

A singular position-dependent mass particle in an infinite potential well

We consider an unusual singular position=dependent-mass particle in an infinite potential well. The corresponding Hamiltonian is mapped through a point-canonical-transformation and an explicit correspondence between the target Hamiltonian and a Poschl-Teller type reference Hamiltonian is obtained. New ordering ambiguity parametric setting are suggested.Comment: 13 pages, no figures. To appear in Phys. Lett.

Ordering ambiguity revisited via position dependent mass pseudo-momentum operators

Ordering ambiguity associated with the von Roos position dependent mass (PDM) Hamiltonian is considered. An affine locally scaled first order differential introduced, in Eq.(9), as a PDM-pseudo-momentum operator. Upon intertwining our Hamiltonian, which is the sum of the square of this operator and the potential function, with the von Roos d-dimensional PDM-Hamiltonian, we observed that the so-called von Roos ambiguity parameters are strictly determined, but not necessarily unique. Our new ambiguity parameters' setting is subjected to Dutra's and Almeida's [11] reliability test and classified as good ordering.Comment: 10 pages, no figures, revised/expanded, mathematical presentations in section 2 (Especially, the typological Errors in Eqs.(9)-(12))are now corrected. To appear in the Int. J. Theor. Phy

Immigrant community integration in world cities

As a consequence of the accelerated globalization process, today major cities all over the world are characterized by an increasing multiculturalism. The integration of immigrant communities may be affected by social polarization and spatial segregation. How are these dynamics evolving over time? To what extent the different policies launched to tackle these problems are working? These are critical questions traditionally addressed by studies based on surveys and census data. Such sources are safe to avoid spurious biases, but the data collection becomes an intensive and rather expensive work. Here, we conduct a comprehensive study on immigrant integration in 53 world cities by introducing an innovative approach: an analysis of the spatio-temporal communication patterns of immigrant and local communities based on language detection in Twitter and on novel metrics of spatial integration. We quantify the "Power of Integration" of cities --their capacity to spatially integrate diverse cultures-- and characterize the relations between different cultures when acting as hosts or immigrants.Comment: 13 pages, 5 figures + Appendi

Modulation of γ-Secretase Reduces β-Amyloid Deposition in a Transgenic Mouse Model of Alzheimer's Disease

SummaryAlzheimer's disease (AD) is characterized pathologically by the abundance of senile plaques and neurofibrillary tangles in the brain. We synthesized over 1200 novel gamma-secretase modulator (GSM) compounds that reduced Aβ42 levels without inhibiting epsilon-site cleavage of APP and Notch, the generation of the APP and Notch intracellular domains, respectively. These compounds also reduced Aβ40 levels while concomitantly elevating levels of Aβ38 and Aβ37. Immobilization of a potent GSM onto an agarose matrix quantitatively recovered Pen-2 and to a lesser degree PS-1 NTFs from cellular extracts. Moreover, oral administration (once daily) of another potent GSM to Tg 2576 transgenic AD mice displayed dose-responsive lowering of plasma and brain Aβ42; chronic daily administration led to significant reductions in both diffuse and neuritic plaques. These effects were observed in the absence of Notch-related changes (e.g., intestinal proliferation of goblet cells), which are commonly associated with repeated exposure to functional gamma-secretase inhibitors (GSIs)

A General Approach for the Exact Solution of the Schrodinger Equation

The Schr\"{o}dinger equation is solved exactly for some well known potentials. Solutions are obtained reducing the Schr\"{o}dinger equation into a second order differential equation by using an appropriate coordinate transformation. The Nikiforov-Uvarov method is used in the calculations to get energy eigenvalues and the corresponding wave functions.Comment: 20 page