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Typical blocking indices in longitude or both longitude and latitude are compared to demonstrate: (1) the central blocking latitude (CBL) should be any of 40-80 degrees N; (2) reversals of meridional gradients in absolute fields (...
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Typical blocking indices in longitude or both longitude and latitude are compared to demonstrate: (1) the central blocking latitude (CBL) should be any of 40-80 degrees N; (2) reversals of meridional gradients in absolute fields (ABS) about specified CBLs or in combination with time anomalies exceeding a threshold missed blocking patterns or misidentified non-blocking structures. Blocking highs are identified by a new Eddy-ABS index. A large-scale high is represented by a local maximum of zonal eddy anomalies, its immediately surrounding points and subsequent contiguous grids with decreasing anomalies but exceeding the 75th percentile. A high with any ABS reversal is an instantaneous blocking (IB). Maximum overlapping IBs become quasi-stationary when moving less than 10 degrees longitudes per day. Four and more quasi-stationary IBs form a blocking event (BE). This unified index has identified IBs and BEs at vertical levels in the Northern (NH) and Southern Hemispheres (SH) during different seasons. In the NH, BEs exhibit strong seasonality, geographical preference and quasi-barotropicity. The lifetime, maximum intensity, impact area, and moving speed have a log-linear, log-normal, log-normal, and normal distribution, respectively. These features occur similarly in the SH, except for very small occurrences at 200 hPa in JJA and a normal distribution for the maximum intensity. Properties other than the moving speed significantly correlate with the maximum intensity in both hemispheres. The missing and misidentification issues are reasonably well resolved by this new index.
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The atrioventricular (AV) bridge is vulnerable to many circumstances that depress conduction. Abnormal impulse transmission may be caused by drugs, autonomic effects, or destructive processes. The familiar separation into 3 degree...
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The atrioventricular (AV) bridge is vulnerable to many circumstances that depress conduction. Abnormal impulse transmission may be caused by drugs, autonomic effects, or destructive processes. The familiar separation into 3 degrees is useful, but occasionally insufficient. Classic type 1 (Wenckebach) AV block is owing to depressed AV nodal conduction and is recognized by a prolonging PR interval ending in a dropped beat. It is frequently owing to drugs that depress conduction through the AV node (digitalis, (3-blockers, and calcium channel blockers.) It is frequently seen with inferior wall myocardial infarction (Fig. 2). Fig. 3 illustrates the effect on AV conduction as successive atrial impulses (1-5) arrive in the AV junction earlier and earlier in it refractory period. The light stippling is the relative refractory period an the dark stippling is absolute refractory period. Fig. 4 depicts the basis of type 1 AV block. The earlier the P wave is, in the wake of the preceding complex, the longer the PR interval will be. Ultimately, the P wave encounters the absolute refractory period and cannot be conducted. Type II (Mobitz) AV block is owing to abnormal infranodal conduction, and is usually accompanied by bundle branch block. All conducted impulses share the same PR intervals (usually normal). The dropped beats appear without warning and may be sporadic or several in a row. Type II block may be seen with anterior infarction, but is not related to drugs in current use. A pacemaker is usually required (Fig. 5).
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Using local blocks in conjunction with other forms of pain relief have been shown to reduce the length of hospital stays and postoperative recovery times in human patients. This article will explain common hindlimb and forelimb lo...
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Using local blocks in conjunction with other forms of pain relief have been shown to reduce the length of hospital stays and postoperative recovery times in human patients. This article will explain common hindlimb and forelimb local blocks using electrostimulation for the correct location of the nerve to provide superior pain relief in small animals when used as part of a multimodal analgesic plan.
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We present an efficient block-wise update scheme for the QR decomposition of block tridiagonal and block Hessenberg matrices. For example, such matrices come up in generalizations of the Krylov space solvers MinRES, SymmLQ, GMRes,...
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We present an efficient block-wise update scheme for the QR decomposition of block tridiagonal and block Hessenberg matrices. For example, such matrices come up in generalizations of the Krylov space solvers MinRES, SymmLQ, GMRes, and QMR to block methods for linear systems of equations with multiple right-hand sides. In the non-block case it is very efficient (and, in fact, standard) to use Givens rotations for these QR decompositions. Normally, the same approach is also used with column-wise updates in the block case. However, we show that, even for small block sizes, block-wise updates using (in general, complex) Householder reflections instead of Givens rotations are far more efficient in this case, in particular if the unitary transformations that incorporate the reflections determined by a whole block are computed explicitly. Naturally, the bigger the block size the bigger the savings. We discuss the somewhat complicated algorithmic details of this block-wise update, and present numerical experiments on accuracy and timing for the various options (Givens vs. Householder, block-wise vs. column-wise update, explicit vs. implicit computation of unitary transformations). Our treatment allows variable block sizes and can be adapted to block Hessenberg matrices that do not have the special structure encountered in the above mentioned block Krylov space solvers.
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Today the block pattern of Skopje's Bazaar, created by the Ottoman urban strategy during the 15th and 16th century, is only partially understood. The aim of this paper is to identify the block typology of the Old Bazaar by analyzi...
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Today the block pattern of Skopje's Bazaar, created by the Ottoman urban strategy during the 15th and 16th century, is only partially understood. The aim of this paper is to identify the block typology of the Old Bazaar by analyzing the relations between form and development. To meet the aim, we analyzed previous research, Skopje's map from 1929 and conducted field survey (09/2011). Based on the data from 1929 map, we identified two other subtypes of facility blocks from the one facility and three shop blocks described in previous research. Most of the surviving blocks still preserve their shape and structure although in some cases an alteration of the block type occurred as a result of the destruction of Ottoman facility or shop rebuilding. We concluded that the historic urban order of the ground plan and the block pattern, created by the systematic relationships of facility, shop and street in the Ottoman urban strategy, are important values of the Bazaar's urban form. As the pressure for modern development surges, the results of this study can facilitate creation of design guidelines for sustainable conservation of the urban form of Skopje's Bazaar.
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A prospective study was conducted to evaluate the efficacy of nerve blocks for postoperative pain relief following foot and ankle surgery. The study included all patients who underwent foot and ankle surgery over a period of three...
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A prospective study was conducted to evaluate the efficacy of nerve blocks for postoperative pain relief following foot and ankle surgery. The study included all patients who underwent foot and ankle surgery over a period of three months. Sciatic/popliteal nerve blocks were administered for hindfoot surgery and ankle blocks for forefoot surgery. Postoperative pain was assessed using visual analog scales and a record was kept of analgesic requirements. Ninety three percent of the patients were satisfied with the pain control and recorded low pain scores and sixty percent of these patients had good pain relief at an average of eighteen hours, without the need for any additional analgesics.
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As the American healthcare system continues to evolve and reimbursement becomes tied to value-based incentive programs, perioperative pain management will become increasingly important. Regional anesthetic techniques are only one ...
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As the American healthcare system continues to evolve and reimbursement becomes tied to value-based incentive programs, perioperative pain management will become increasingly important. Regional anesthetic techniques are only one component of a successful multimodal pain regimen. In recent years, the use of peripheral and paraneuraxial blocks to provide chest wall and abdominal analgesia has gained popularity. When used within a multimodal regimen, truncal blocks may provide similar analgesia when compared with other regional anesthetic techniques. While there are other reviews that cover this topic, our review will also highlight the emerging role for serratus plane blocks, pectoral nerve blocks and quadratus lumborum blocks in providing thoracic and abdominal analgesia.
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The orientation, trace length, spacing, and location of probabilistic discontinuities in rock masses are randomly developed. Thus, the shape, size, and location of blocks cut off by these probabilistic discontinuities are accordin...
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The orientation, trace length, spacing, and location of probabilistic discontinuities in rock masses are randomly developed. Thus, the shape, size, and location of blocks cut off by these probabilistic discontinuities are accordingly stochastic. It is difficult, or even impossible, to determine the volume and location of the blocks using the block theory proposed by Goodman and Shi (1985). Stochastic block analysis (SBA) is capable of identifying three-dimensional (3-D) stochastic blocks from a randomly developed discontinuity network (discrete fracture network). However, in practice, 3-D blocks are not identified well in simulated fracture networks and so the use of SBA is seldom encountered. In this paper, the procedures involved in stochastic block identification are first outlined. The concept and calculation of overlaying area and ratio are then introduced. Then, the stochastic block identification results are used to explore the statistical distribution of the block size and overlaying ratio. Subsequently, the laws governing development of the stochastic blocks were elucidated. The results show that the block size has a negative exponential distribution and the overlaying ratio follows a Γ distribution. The overlaying ratio increases as the trace length to spacing ratio increases. We further outline, for the first time, approaches to determine block support measures by analyzing the characteristics of the statistical distributions of the stochastic blocks. Block support issues relating to a practical underground plant were also studied. The lengths and anchor forces and spacings of the rock bolts were quantitatively determined according to the results of a statistical analysis of the stochastic blocks. Statistical analysis of stochastic blocks is of great significance in understanding the development characteristics of the stochastic blocks and in quantitatively determining block support measures.
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A new block-classification method for tunnel construction using a tunnel-boring machine (TBM) to capture the geometrical and mechanical transformation of rock blocks in the course of TBM excavation is proposed in this pape
A new block-classification method for tunnel construction using a tunnel-boring machine (TBM) to capture the geometrical and mechanical transformation of rock blocks in the course of TBM excavation is proposed in this paper. The machine–block interaction is interpreted by dividing the joint blocks into blocks influenced by TBM excavation and blocks uninfluenced by TBM excavation. The influenced blocks are categorized further as contacting or noncontacting blocks according to whether they are in contact with the TBM. The contacting blocks include the front block, the corner block, and the rear block, based on the spatial location of blocks with respect to the cutterhead. Different types of blocks have distinct kinematic and mechanical characteristics. The sizes and shapes evolve, and the categories may be changed for rock blocks during excavation. The identification algorithms for influenced blocks and three types of contacting blocks are presented. Finally, a simple example considering a double-shield TBM tunnel excavation is used to illustrate the effectiveness of the new block-classification approach to guide TBM tunneling. The new classification approach will be helpful in evaluating the block removability and the possibility of cutterhead clogging and to shield blockage during tunneling with a TBM.
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