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    Ganga Ma

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    Concord, MA

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    Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

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    Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs

    Point-source scalar turbulence

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    The statistics of a passive scalar randomly emitted from a point source is investigated analytically. Our attention has been focused on the two-point equal-time scalar correlation function. The latter is indeed easily related to the spectrum, a statistical indicator widely used both in experiments and in numerical simulations. The only source of inhomogeneity/anisotropy is in the injection mechanism, the advecting velocity here being statistically homogeneous and isotropic. Our main results can be summarized as follows. 1) For a very large velocity integral scale, a pure scaling behaviour in the distance between the two points emerges only if their separation is much smaller than their distance from the point source. 2) The value we have found for the scaling exponent suggests the existence of a direct cascade, in spite of the fact that here the forcing integral scale is formally set to zero. 3) The combined effect of a finite inertial-range extension and of inhomogeneities causes the emergence of subleading anisotropic corrections to the leading isotropic term, that we have quantified and discussed.Comment: 10 pages, 1 figure, submitted to Journal of Fluid Mechanic

    MA

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    thesisThough Hamas is an organization based upon a distinct ideology and emphasizes the rigidity of its adherence to that ideology, its external relations reveal it as a pragmatic and logical actor. Constantly aware of its dependence on external financial aid and its popular support base, Hamas's actions have been carefully calculated to ensure that it gains and retains the greatest amount of latent power. Through this interpretation, Hamas's relationships with external entities, whether they are Islamist, Nationalist, or state actors, has changed as time and circumstance dictate. Viewing Hamas as a rational actor allows states and other organizations to begin to develop stronger ties to it that may prove beneficial to all the parties involved. It will be seen that those entities that see Hamas as pragmatic and rational work closely and/or emphasize the need for negotiation in order to integrate Hamas into the international community

    MA

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    thesisThe great importance of fuels and their utilization to the industrial and domestic progress of cities and nations, has directed the attention of many of our leading scientists, engineers, and forward looking people to newer ways by which our fuel resources can be so utilized to bring many benefits to the general scale and plane of living. Utah is fortunate in having received many years of state and federal cooperative study of her oil shale and coal resources, with respect to their by-products. These studies have proved the reserves of oil in oil shales and coals of Utah to be very extensive, and many times greater than any of the present proved petroleum fields. Recent research and experimental evidences are changing with respect to the order of development of the oil shale and coal reserves. It has been the generally accepted idea that oil shale was a more likely source of oil than coal. Industrial activity, also, has tended more in the development of oil shales than coal for production of oil in the past. But later developments in the manufacture of oil from coal are tending to reverse the situation

    MA

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    thesisThere were at least two types of chemoautotrophic thiobacilli found in the leaching streams of Bingham Canyon min dump. One of these organisms oxidizes free sulfur to sulfuric acid which reaction is its energy reaction. This organism is very similar to Thiobacillus thiooxidans. The other organism oxidizes ferrous to ferric ion as its initial energy reaction and is similar to thiobacillus ferrooxidans. These two bacterial strains complement each other in that T. thiooxidans produces acid which keeps the ferric ion produced by T. ferrooxidans in solution, thereby forming an effective acidic ferric sulfate leaching solution for copper minerals. In addition to these two types of chemoautotrophs, a yeast-like organism was found in every location of the Bingham mine dump waters. The cell biology and physiology of these yeast-type organisms were studied. It was found not to be a chemoautotrophic, but an acidophilic heterotroph. The microbial population in the mine water samples suggests the coexistence of a balanced ecological system in which carbon fixation is dependent on chemoautotrophic bacteria. Acidophilic heterotrophs, utilizing organic matter as their energy and carbon source, are acting to keep the organic content of leach waters at a low concentration favorable to the development of chemoautotrophs. Three different counting techniques, such as a Petroff-Hausser counting technique, the silica gel plate counting technique and the radioisotope labeling technique for the enumeration of the chemoautotrophic thiobacilli were studies. Of these methods, the direct microscopic counts were the only ones found to be satisfactory as the most rapid and relatively reliable method of estimating this type of cell numbers. Statistical evaluation of Petroff-Hausser counting technique was also made to prove the reliability of this method. The correlation between the conversion of ferrous to ferric ion and bacterial growth were studies. It was shown that a given amount of conversion of ferrous to ferric ion over a given time period corresponded to a given increase in the bacterial population. The distribution of Thiobacillus ferrooxidans and their ecological environment in the Bingham mine dump were investigated. It was noted that there was a relationship between the numbers of T. ferrooxidans in leaching systems and the chemical reactions which were known to occur in this process

    MA

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    thesisThe external branch of the superior laryngeal nerve (ESLN) innervates the cricothyroid (CT) muscle of the larynx, a vocal fold tensor primarily responsible for pitch elevation. For over 100 years, a controversy has existed regarding the laryngeal signs that should be considered pathognomonic of unilateral ESLN paralysis. Regrettably, little progress has been made in resolving this controversy, as the extant clinical literature is characterized by contradiction and inconsistency. Myriad descriptions exist of the laryngeal behaviors ostensibly associated with unilateral ESLN denervation. To address this longstanding controversy and improve diagnostic precision, this preliminary investigation aimed to model "in vivo" acute, unilateral CT dysfunction by temporarily blocking the ESLN using lidocaine hydrochloride (HCL), and verifying selective denervation using laryngeal electromyography (LEMG). The purpose of this investigation was twofold: (1) to identify the salient laryngeal features associated with acute denervation (i.e., the pathognomonic features of unilateral CT dysfunction), and (2) to identify a set of laryngeal tasks that maximally provoke or reveal ESLN dysfunction, thereby contributing to a set of diagnostic tasks/markers that will improve diagnostic accuracy during clinical assessment. Ten vocally normal adult males (mean age = 25 yrs.; range = 19 to 29 years) underwent lidocaine block of the right ESLN, and flexible videolaryngostroboscopic (FVLS) recordings were acquired before and during the block. Eleven blinded, expert judges (6 laryngologists and 5 Ph.D. speech-language pathologists) rated randomized, pre- vs. during-block recordings of 10 vocal tasks using standard FVLS rating protocols. Contrary to clinical reports, no evidence of hypomobility/sluggishness of the ipsilateral vocal fold, or a reliable pattern of axial rotation of the larynx during high pitch voice was observed. Furthermore, no evidence was observed to support reduced vocal fold longitudinal tension, aryepiglottic fold length asymmetry, phase asymmetry, vocal fold plane differences, or glottic insufficiency, as diagnostic features of unilateral CT dysfunction. Instead, the analysis revealed (1) a pattern of deviation of the petiole of the epiglottis to the side of weakness (i.e., the right) in 60% of participants during a glissando up maneuver produced at normal volume, and (2) a pattern of axial rotation of the posterior commissure to the left and the anterior commissure to right in 50% of participants during a maneuver which rapidly alternated between a maximum vocal fold abduction task (Sniff) and a high-pitched "ee" production. Both of these findings have not been previously reported elsewhere, and potentially represent new diagnostic markers of unilateral CT paralysis. The results are discussed with respect to their clinical implications, and the necessity to explore both females and clinical populations to better appreciate the clinical utility of these diagnostic signs

    The Richardson's Law in Large-Eddy Simulations of Boundary Layer flows

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    Relative dispersion in a neutrally stratified planetary boundary layer (PBL) is investigated by means of Large-Eddy Simulations (LES). Despite the small extension of the inertial range of scales in the simulated PBL, our Lagrangian statistics turns out to be compatible with the Richardson t3t^3 law for the average of square particle separation. This emerges from the application of nonstandard methods of analysis through which a precise measure of the Richardson constant was also possible. Its values is estimated as C2‚ąľ0.5C_2\sim 0.5 in close agreement with recent experiments and three-dimensional direct numerical simulations.Comment: 15 LaTex pages, 4 PS figure

    Edgeworth and Moment Approximations: The Case of MM and QML Estimators for the MA(1) Models

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    Extending the results in Sargan (1976) and Tanaka (1984), we derive the asymptotic expansions, of the Edgeworth and Nagar type, of the MM and QML estimators of the 1^{st} order autocorrelation and the MA parameter for the MA(1) model. It turns out that the asymptotic properties of the estimators depend on whether the mean of the process is known or estimated. A comparison of the Nagar expansions, either in terms of bias or MSE, reveals that there is not uniform superiority of neither of the estimators, when the mean of the process is estimated. This is also confirmed by simulations. In the zero-mean case, and on theoretical grounds, the QMLEs are superior to the MM ones in both bias and MSE terms. The results presented here are important for deciding on the estimation method we choose, as well as for bias reduction and increasing the efficiency of the estimators.Edgeworth expansion, moving average process, method of moments, Quasi Maximum Likelihood, autocorrelation, asymptotic properties.
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