3,460 research outputs found

    Establishment and Growth of Cherrybark Oak Seedlings Underplanted Beneath a Partial Overstory in a Minor Bottom of Southwestern Arkansas: First Year Results

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    -Advance regeneration is frequently inadequate to sufficiently restock the oak component of many bottomland stands, especially on productive sites with high levels of competition. We initiated a study near Beirne, AR to examine the effects of pre-plant control of Japanese honeysuckle Thunberg) and seedling quality on establishment success and vigor of oak reproduction beneath a partial canopy. Nine, 2-acre plots were delineated in the stand that was harvested a residual stocking level of 30 percent in the fall of 1996. Honeysuckle pre-plant control treatments randomly applied to the nine were an Escort application in the spring of 1997, an Escort application in the summer of 1997, and a control (no herbicide application). In 1998, 1-O cherrybark oak (Quercus pagoda Raf.) seedlings were planted at a 12 ft x 12 ft spacing in each treatment plot. One-half of each treatment plot received seedlings with four or more roots 0.04 in. diameter, while the other half of each plot received seedlings with fewer than four lateral roots 0.04 in. The spring application of Escort provided effective control against Japanese honeysuckle, thereby producing potentially promising conditions for oak seedling growth and development. First-year seedling survival and growth did not respond to honeysuckle control treatments. Survival was not related seedling quality, and first-year differences in seedling size were attributed to initial size differences in stock types

    Epidemiological aspects of surgical site infections in an income country. The case of regional hospital center, Borgou (Benin)

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    ABSTRACT Background: Surgical site infection is frustrating for the care team and depressing for the patient. Objective: To determine the epidemiological aspects of surgical site infections in regional hospital, Borgou. Methods: The study was crossed with prospective data collection. Recruitment was done for six months (from February 2013 to July 2013), each patient operated in both surgical services (general surgery and maternity) consents to be followed for one month or year. The surgical site infection was defined according to the CDC/NHSN 2009. Results: The frequency of surgical site infections was 7.3% (44/603). The mean age was 30.7 ± 15.8 years with minimum and maximum of 5 months and 70 years, respectively. They were significantly (p<0.05) more common in general surgery than that of maternity and visceral surgery and obstetrics were more concerned (14/44 each); the median time to SSI onset was 7.8 ± 3.8 days. The deep incisional infection was the most frequent (34/44). The most encountered organism was Escherichia coli (64.7%); multidrug resistance was 41.2%. The healing time averaged 30.5 ± 13.8 days with minimum and maximum of 20 and 92 days. Conclusion: Monitoring measures must be taken to reduce surgical site infection at the Regional Hospital Centre of Borgou.Background: Surgical site infection is frustrating for the care team and depressing for the patient. Objective: To determine the epidemiological aspects of surgical site infections in regional hospital, Borgou. Methods: The study was crossed with prospective data collection. Recruitment was done for six months (from February 2013 to July 2013), each patient operated in both surgical services (general surgery and maternity) consents to be followed for one month or year. The surgical site infection was defined according to the CDC/NHSN 2009. Results: The frequency of surgical site infections was 7.3% (44/603). The mean age was 30.7 ± 15.8 years with minimum and maximum of 5 months and 70 years, respectively. They were significantly (p<0.05) more common in general surgery than that of maternity and visceral surgery and obstetrics were more concerned (14/44 each); the median time to SSI onset was 7.8 ± 3.8 days. The deep incisional infection was the most frequent (34/44). The most encountered organism was Escherichia coli (64.7%); multidrug resistance was 41.2%. The healing time averaged 30.5 ± 13.8 days with minimum and maximum of 20 and 92 days. Conclusion: Monitoring measures must be taken to reduce surgical site infection at the Regional Hospital Centre of Borgou

    Quantum Langevin theory of excess noise

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    In an earlier work [P. J. Bardroff and S. Stenholm], we have derived a fully quantum mechanical description of excess noise in strongly damped lasers. This theory is used here to derive the corresponding quantum Langevin equations. Taking the semi-classical limit of these we are able to regain the starting point of Siegman's treatment of excess noise [Phys. Rev. A 39, 1253 (1989)]. Our results essentially constitute a quantum derivation of his theory and allow some generalizations.Comment: 9 pages, 0 figures, revte

    A note on the integral equation for the Wilson loop in N = 2 D=4 superconformal Yang-Mills theory

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    We propose an alternative method to study the saddle point equation in the strong coupling limit for the Wilson loop in N=2\mathcal{N}=2 D=4 super Yang-Mills with an SU(N) gauge group and 2N hypermultiplets. This method is based on an approximation of the integral equation kernel which allows to solve the simplified problem exactly. To determine the accuracy of this approximation, we compare our results to those obtained recently by Passerini and Zarembo. Although less precise, this simpler approach provides an explicit expression for the density of eigenvalues that is used to derive the planar free energy.Comment: 12 pages, v2: section 2.5 (Free Energy) amended and reference added, to appear in J. Phys.

    High performance WR-1.5 corrugated horn based on stacked rings

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    We present the development and characterisation of a high frequency (500-750 GHz) corrugated horn based on stacked rings. A previous horn design, based on a Winston profile, has been adapted for the purpose of this manufacturing process without noticeable RF degradation. A subset of experimental results obtained using a vector network analyser are presented and compared to the predicted performance. These first results demonstrate that this technology is suitable for most commercial applications and also astronomical receivers in need of horn arrays at high frequencies.Comment: 9 page

    Andrew Melville, sacred chronology and world history: the Carmina Danielis 9 and the Antichristus

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    The accepted view of the ecclesiastical reformer Andrew Melville (1545–1622) as the dynamic leader of the Presbyterian movement in Jacobean Scotland has been severely eroded in recent years, with particular criticism of the actual importance of his contribution to the Kirk and to Scottish higher education. While this reductionism has been necessary, it has resulted in an inversion of the overwhelmingly positive traditional image of Melville, and does not give us a rounded assessment of his life and works. This article attempts to partially redress this balance by looking at a neglected aspect of Melville's Latin writings, which showcase his talents as a humanist intellectual and biblical commentator. It focuses on two long poems that are both commentaries and paraphrases of Daniel and Revelation: the Carmina Danielis and the Antichristus. Through these poems, we see how Melville engaged with two problems exercising reformed theologians across Europe: the dating of key biblical events and the historicised meaning of prophecies within these texts. We also find evidence that Melville read widely among both contemporary and ancient commentators on both these issues

    An elasto-visco-plastic model for immortal foams or emulsions

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    A variety of complex fluids consist in soft, round objects (foams, emulsions, assemblies of copolymer micelles or of multilamellar vesicles -- also known as onions). Their dense packing induces a slight deviation from their prefered circular or spherical shape. As a frustrated assembly of interacting bodies, such a material evolves from one conformation to another through a succession of discrete, topological events driven by finite external forces. As a result, the material exhibits a finite yield threshold. The individual objects usually evolve spontaneously (colloidal diffusion, object coalescence, molecular diffusion), and the material properties under low or vanishing stress may alter with time, a phenomenon known as aging. We neglect such effects to address the simpler behaviour of (uncommon) immortal fluids: we construct a minimal, fully tensorial, rheological model, equivalent to the (scalar) Bingham model. Importantly, the model consistently describes the ability of such soft materials to deform substantially in the elastic regime (be it compressible or not) before they undergo (incompressible) plastic creep -- or viscous flow under even higher stresses.Comment: 69 pages, 29 figure
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