Pseudo Hermitian interactions in the Dirac Equation

We consider $(2+1)$ dimensional massless Dirac equation in the presence of complex vector potentials. It is shown that such vector potentials (leading to complex magnetic fields) can produce bound states and the Dirac Hamiltonians are $\eta$-pseudo Hermitian. Some examples have been explicitly worked out.Comment: 8 pages, NO figure

Investigations with monozygous twin dairy heifers

Monozygous twins have been reported to have a higher value than non-twins for experimental studies comparing two treatments, because these twins have no inherited differences. Differences which develop between identical twins are due to environment. Physiological processes such as growth and milk production are very complex and are regulated in some degree by more simple processes. Since monozygous twins are expected to react similarly in growth and production, they should also be expected to react similarly in less complex functions. Two physiological processes of particular interest in dairy cattle are the efficiency of feed utilization and the adaptability to high ambient temperatures. This investigation was planned to measure the differences in the physiological processes of monozygotic dairy heifers under the same environment and compare these differences with ones found within pairs of selected animals of the same age and weight. Growth of identical twin pairs fed at the same level and other pairs of identical twins at different levels of nutrition was measured. All data were compared to determine the value of Identical twins for experimental observations involving physiological processes

Central Pain Following a Collagenase-Induced Hematoma in the Basal Ganglia and Thalamus Can Be Reversed with Gabapentin

The objective of this study was to evaluate pain sensitization in rats following the induction of an intracerebral haemorrhage located in the basal ganglia and/or thalamus using the Rosenberg model (intracerebral injection of collagenase). Thirty male Sprague-Dawley rats weighing between 175-300 g were used. In a first experiment, 3 groups of 6 animals were used to evaluate pain threshold using the Hargreaves test (thermal sensitivity). Following 3 days of behavioural testing (baseline values), animals in each group were injected intracerebrally either with 0.5, 1 or 2 μL of a collagenase solution (0.5 U/2 μL Type VII collagenase) which induced a hematoma in the right caudoputamen nucleus and/or thalamus. They were then tested for the next 9 consecutive days. No pain-related behavioural changes were observed following injections with 0.5 and 1 μL of collagenase. However with 2 μL, reaction times were significantly faster on days 3, 4, 5, 6 (p < 0.0001) and 7 (p < 0.006) in the right and left hind paws compared to baseline values. The lesion was localized only in the caudoputamen nucleus for animals receiving 0.5 and 1 μL of collagenase whereas lesions extended in the ipsilateral thalamic nuclei (lateral-dorsal and lateral-posterior nuclei) for animals receiving 2 μL of collagenase. In a second experiment, gabapentin reversed mechanical allodynia, evaluated with von Frey filaments, and hyperalgesia, evaluated with Hargreaves test, in rats (n=6) following a collagenase-induced (3 μL) hematoma. In conclusion, these preliminary results suggest that central pain was induced in rats with a collagenase-induced intracerebral haemorrhage localized in the caudoputamen nuclei most probably associated with lesions to the thalamus, and concurrent allodynia and hyperalgesia were reduced with gabapentin treatment

Modelo de valoración y comparación de empresas

Proyecto de graduación (Maestría en Administración de Empresas con énfasis en Finanzas) Instituto Tecnológico de Costa Rica, Escuela de Administración de Empresas, 2014.The companies SIEMENS and EATON, they are companies that belong to a same industry and engaged in the technological area. The information used in this paper is only for academic purposes and it was generated through the website yahoo.finance.com. SIEMENS is one company in the technological sector in industry instruments and electrical devices with 360 000 employees and is located in Germany. EATON is a technology company that operates as a worldwide energy management company. The company was founded in 1916 and is headquartered in Dublin, Ireland, with 102 000 employees. Its electrical products segment offers electrical components, industrial components, among others. The realization of this project allowed to develop a model of evaluation and comparison of companies like SIEMENS and EATON, in the period between 2011 and 2013, in order to analyze models or valuation methodologies currently used, validate the existence or application of valuation models of companies and their use in the domestic market; as well as carry out the valuation of the same process. Was the projection of the financial statements for the years 2011-2013, obtaining positive cash flows for the three years. For this two companies in study we applied the analysis model in order to get an idea about the behavior of each company in terms of their financial health. The integral scheme of profitability was used to determine what were the factors that have major impact in profitability on the equity and an strength analysis, where it was determined the capacity that businesses have to meet their obligations. 7 This analysis leads to the conclusion that these two companies have the maturity and a world class performance, both companies has significant differences however both are generating value to their stakeholders. Using the results obtained, shows that these two companies have managed stable operations a long their lifetime. However the analysis indicates that SIEMENS has a more positive performance, while EATON has a less aggressive performance but stable on his periods on study. There are situations like local and global changes that may affect company performance, but is EATON behavior the one that shows better balance in their long-term commitments, equities and financing administration, suggesting greater solid financial structure and a secure investing option

Relationship between esomeprazole dose and timing to heartburn resolution in selected patients with gastroesophageal reflux disease

Roy C Orlando1, Sherry Liu2, Marta Illueca31Department of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC, USA, 2Department of Statistics and Informatics, 3Department of Clinical Development, AstraZeneca LP, Wilmington, DE, USAObjective: To increase response rates to therapy by increasing the dosage of proton pump inhibitor (PPI) therapy in patients with gastroesophageal reflux disease (GERD) whose symptoms are predominantly associated with acid reflux.Methods: In this double-blind, randomized, proof-of-concept study, 369 patients with GERD and moderate heartburn lasting ≥three days/week, a history of response to antacids/acid suppression therapy, and a positive esophageal acid perfusion test result were randomized to esomeprazole 20 or 40 mg once daily, or to 40 mg twice daily for four weeks. Heartburn symptom relief/resolution was subsequently evaluated.Results: In this study population, no relationship was apparent between esomeprazole dosage and efficacy variables for sustained heartburn resolution (seven days without symptoms) at week 4 (48.0%, 44.0%, and 41.4% for esomeprazole 20 mg once daily, 40 mg once daily, and 40 mg twice daily, respectively). Nocturnal heartburn resolution with esomeprazole 40 mg twice daily showed a numeric improvement trend versus esomeprazole 20 and 40 mg once daily, but this was not statistically significant.Conclusions: Heartburn resolution rates at four weeks were similar for all esomeprazole dosages and comparable with rates reported previously, suggesting a plateau effect in terms of clinical response to acid suppression with PPI therapy in this population of selected GERD patients.Keywords: acid suppressive therapy, GERD, proton pump inhibito

Interferometer based on a D-shape chaotic optical fiber for measurement of multiparameters

International audienceAn interferometer based on a D-shape chaotic optical fiber for measurement of multiparameters was proposed. The sensing structure relied on a D-shape fiber section spliced in between two singlemode fibers and interrogated in transmission. The optical spectrum was composed by multiple interference loss peaks, which were sensitive to the refractive index, temperature and strain - maximum sensitivities of 95.2 nm/RIU, 10.5 pm/℃ and -3.51 pm/με, respectively, could be achieved

Dilated intercellular spaces and chronic cough as an extra-oesophageal manifestation of gastrooesophageal reflux disease

Chronic cough is one of the extra-oesophageal manifestations of gastrooesophageal reflux disease (GORD). It is presumed to occur either directly by microaspiration of acidic gastric contents into the airway or indirectly by a reflex triggered by contact of acidic refluxates with the oesophageal epithelium in GORD. How contact of the oesophageal epithelium with acidic refluxates promotes sensitization for chronic cough is unknown, but like heartburn, which is a necessary accompaniment, it requires acid activation of nociceptors within the oesophageal mucosa. Dilated intercellular spaces within the oesophageal epithelium, a reflection of an increase in paracellular permeability, is a histopathologic feature of both erosive and nonerosive forms of GORD. Since it correlates with the symptom of heartburn, it is hypothesized herein that the increase in paracellular permeability to acid reflected by dilated intercellular spaces in oesophageal epithelium also serves as mediator of the signals that produce the reflex-induced sensitization for cough – a sensitization that can occur centrally within the medullary Nucleus Tractus Solitarius or peripherally within the tracheobronchial tree

The integrity of the esophageal mucosa. Balance between offensive and defensive mechanisms

Heartburn is the most common and characteristic symptom of gastroesophageal reflux disease. It ultimately results from contact of refluxed gastric acid with nociceptors within the esophageal mucosa and transmission of this peripheral signal to the central nervous system for cognition. Healthy esophageal epithelium provides an effective barrier between refluxed gastric acid and esophageal nociceptors; but this barrier is vulnerable to attack and damage, particularly by acidic gastric contents. How gastric acid is countered by defensive elements within the esophageal mucosa is a major focus of this discussion. When the defense is successful, the subject is asymptomatic and when unsuccessful, the subject experiences heartburn. Those with heartburn commonly fall into one of three endoscopic types: nonerosive reflux disease, erosive esophagitis and Barrett's esophagus. Although what determines endoscopic type remains unknown; it is proposed herein that inflammation plays a key, modulating role

Chemical modification of bacterial cellulose for the development of an antibacterial wound dressing

Bacterial cellulose is a bacterially derived polymer with great potential for application in wound healing due to its innate properties such as high biocompatibility and biodegradability. In addition to this, it is naturally biosynthesized by bacteria as a hydrogel, which makes it an optimal substrate for the treatment of dry wounds, where additional moisture is required to facilitate the healing process. However, this polymer lacks antibacterial properties. As bacterial infections are becoming increasingly common and difficult to treat due to antimicrobial resistance, it is of crucial importance to develop strategies for the modification of cellulose to ensure protection against bacterial contamination. In this study, a green-chemistry approach was proposed for the functionalization of cellulose to introduce antibacterial functional groups. Two different active agents, namely glycidyl trimethylammonium chloride and glycidyl hexadecyl ether, were used for the covalent derivatization of the hydroxyl groups of glucose through a heterogeneous reaction in basic aqueous conditions. The modified material was chemically and mechanically characterized by solid-state techniques and rheological measurements. A biological assessment was then carried out both using bacterial cells and human keratinocytes. It was observed that the functionalization performed induced a reduction of approximately half of the bacterial population within 24 h of direct contact with Staphylococcus aureus subsp. aureus Rosenbach 6538PTM and Escherichia coli (Migula) Castellani and Chalmers ATCC® 8739TM (respectively, a reduction of 53% and 43% in the cell number was registered for the two strains). In parallel, cytotoxicity studies performed on keratinocytes (HaCaT cell line) showed cell viability in the range of 90 to 100% for up to 6 days of direct contact with both unmodified and modified samples. The morphology of the cells was also visually evaluated, and no significant difference was noted as compared to the control. Finally, the in vitro scratch assay evidenced good wound closure rates in the presence of the samples, with complete coverage of the scratched area after 5 days for both the modified cellulose and the positive control (i.e., keratinocytes growth medium). Overall, the modified hydrogel showed promising features, confirming its potential as an alternative substrate to develop a sustainable, antibacterial and biocompatible wound dressing