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\"This book compares the roles of civil professionals in most American Westerns to those in work on the 1910 Mexican Revolution. Included are studies on the Santiago Toole novels by Richard Wheeler, Strange Lady in Town with Greer Garson and La sombra del Caudillo by Martín Luis Guzmán\"-- Provided by publisher.

Design recommendations are presented for calculating the immediate deflection of cracked prestressed concrete members under service loads. Inconsistency and sometimes confusion regarding the calculation of immediate deflection for the different approaches presently available highlight the need for a rational approach toward computing deflection. The ACI 318-19 approach for reinforced (nonprestressed) concrete is broadened to include prestressed concrete. This involves the implementation of an effective moment of inertia, taken together with an effective eccentricity of the prestressing steel, used to define the effective curvature and/or camber from the prestressing force. Proposed revisions to ACI 318 are presented for prestressed Class T and Class C flexural members, and clear steps are provided for calculating immediate deflection. The effectiveness of the new approach is validated against an extensive database of test results, showing reasonable accuracy and reliability in predicting deflections. The paper concludes with practical recommendations for implementation and a worked-out example to illustrate the proposed methodology. These findings aim to enhance the accuracy and consistency of deflection predictions in prestressed concrete design, contributing to better serviceability and performance of concrete structures. Keywords: cracking; effective eccentricity; effective moment of inertia; immediate deflection; prestressed concrete; serviceability; structural design.

Surgical site infections (SSIs) are among the most preventable health-care-associated infections and are a substantial burden to health-care systems and service payers worldwide in terms of patient morbidity, mortality, and additional costs. SSI prevention is complex and requires the integration of a range of measures before, during, and after surgery. No international guidelines are available and inconsistencies in the interpretation of evidence and recommendations of national guidelines have been identified. Given the burden of SSIs worldwide, the numerous gaps in evidence-based guidance, and the need for standardisation and a global approach, WHO decided to prioritise the development of evidence-based recommendations for the prevention of SSIs. The guidelines take into account the balance between benefits and harms, the evidence quality, cost and resource use implications, and patient values and preferences. On the basis of systematic literature reviews and expert consensus, we present 13 recommendations on preoperative preventive measures.

Changes in ACI 318-19 and elsewhere to the effective moment of inertia [I.sub.e], used for computing the immediate deflection of reinforced (non-prestressed) concrete, have led to renewed interest in the serviceability conditions related to deflection. The focus of this study is to extend the approach adopted by ACI 318 for reinforced concrete to prestressed concrete. A review of basic concepts used to formulate a rational model for computing the short- and long-term deformation of reinforced concrete forms the basis of a deformation model for prestressed concrete cracked under service loads. Two viable alternatives expected to provide a reasonably consistent prediction of the deformation are evaluated. One approach employs an offset in the cracked section response to develop an expression for [I.sub.e] used to compute the deformation relative to the offset, while the other approach treats deformation from the load and prestressing separately. Factors affecting the deflection of prestressed concrete are assessed and help explain why comparing the existing and proposed models with test data might not always lead to reliable predictions. Keywords: deflection; effective moment of inertia; prestressed concrete; reinforced concrete.

The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014. We updated the search for MEDLINE for the period between Feb 1, 2014, and May 25, 2016. We included studies most relevant to our predefined question: is the use of laminar airflow in the operating room associated with the reduction of overall or deep SSI as outcomes in patients of any age undergoing surgical operations? We excluded studies not relevant to the study question, studies not in the selected languages, studies published before Jan 1, 1990, or after May 25, 2016, meeting or conference abstracts, and studies of which the full text was not available. Data were extracted by two independent investigators, with disagreements resolved through further discussion. Authors were contacted if the full-text article was not available, or if important data or information on the paper's content was absent. Studies were assessed for publication bias. Grading of recommendations assessment, development, and evaluation was used to assess the quality of the identified evidence. Meta-analyses were done with RevMan (version 5.3). We identified 1947 records of which 12 observational studies were comparing laminar airflow ventilation with conventional turbulent ventilation in orthopaedic, abdominal, and vascular surgery. The meta-analysis of eight cohort studies showed no difference in risk for deep SSIs following total hip arthroplasty (330 146 procedures, odds ratio [OR] 1·29, 95% CI 0·98–1·71; p=0·07, I2=83%). For total knee arthroplasty, the meta-analysis of six cohort studies showed no difference in risk for deep SSIs (134 368 procedures, OR 1·08, 95% CI 0·77–1·52; p=0·65, I2=71%). For abdominal and open vascular surgery, the meta-analysis of three cohort studies found no difference in risk for overall SSIs (63 472 procedures, OR 0·75, 95% CI 0·43–1·33; p=0·33, I2=95%). The available evidence shows no benefit for laminar airflow compared with conventional turbulent ventilation of the operating room in reducing the risk of SSIs in total hip and knee arthroplasties, and abdominal surgery. Decision makers, medical and administrative, should not regard laminar airflow as a preventive measure to reduce the risk of SSIs. Consequently, this equipment should not be installed in new operating rooms. None.

This paper evaluates the approach adopted by ACI 318-19 for computing deflection of reinforced concrete. Comparison is made with the European approach and Branson's approach used in previous editions of ACI 318. The adopted approach uses a rational expression for the effective moment of inertia, [I.sub.e], with a reduced cracking moment that gives greater values of computed deflection for lightly reinforced slabs. The impact of this change on member stiffness and minimum thickness requirements related to immediate and long-term deflection limits for serviceability is evaluated for beams and one-way slabs. Appropriate limits for maximum service load and member span are provided for slabs, and more stringent requirementsare needed for minimum thickness of beams. Information about two-way slabs is also provided. Keywords: beams; deflection; effective moment of inertia; minimum thickness; slabs.

Surgical site infections (SSIs) are the most common health-care-associated infections in developing countries, but they also represent a substantial epidemiological burden in high-income countries. The prevention of these infections is complex and requires the integration of a range of preventive measures before, during, and after surgery. No international guidelines are available and inconsistencies in the interpretation of evidence and recommendations in national guidelines have been identified. Considering the prevention of SSIs as a priority for patient safety, WHO has developed evidence-based and expert consensus-based recommendations on the basis of an extensive list of preventive measures. We present in this Review 16 recommendations specific to the intraoperative and postoperative periods. The WHO recommendations were developed with a global perspective and they take into account the balance between benefits and harms, the evidence quality level, cost and resource use implications, and patient values and preferences.

The ACI 318 Building Code computes time-dependent deflections from creep and shrinkage as the product of immediate deflection from sustained loads and a deflection multiplier that depends on the duration of loading and amount of compression reinforcement. An alternative methodology is proposed that extends the approach developed for an effective moment of inertia [I.sub.e], recently adopted by ACI 318-19 for computing immediate deflection to include time-dependent deflections from creep under sustained load and shrinkage. Separate components are developed for creep and shrinkage deformation based on a rational tension stifening model that accounts for the reduced member stiffness from creep, shrinkage warping of the uncracked and cracked sections, and loss of stiffness from a lower cracking moment that results as tensile stresses develop in the concrete from restraint to shrinkage and cause additional cracking. Comparison is also made with the Eurocode 2 approach. Validation with long-term test data shows close agreement within a few percent for the proposed approach and Eurocode 2 approach. ACI 318-14 underestimates deflection by 27% and ACI 318-19 overestimates deflection by 23% for the test results evaluated in this study. Keywords: beams; creep; deflection; effective moment of inertia; long-term; shrinkage; slabs.

Prediction of immediate deflection is evaluated for cracked prestressed concrete members using integration of curvature. Integration accounts for changes in member stiffness and strand eccentricity along the member length when applicable. Several approaches are considered, including a bilinear momentdeformation response and those using an effective moment of inertia based either on an effective prestress moment defined by an effective eccentricity of the prestress force or an offset in the cracked response with tension stiffening. Comparison is also made with deflection computed directly, assuming a uniform member stiffness based on the effective moment of inertia at the critical section where the moment is greatest. Results are evaluated using an extensive database for beams either fully or partially prestressed. The beams are simply supported under two-point loading and have a straight tendon profile with constant eccentricity. Integration of curvature is observed to improve prediction of immediate deflection in general and depends not only on the approach used but on several factors that include the cracking moment, elastic modulus of concrete, and the effect of approximating uncracked section properties with gross section properties.

Variability of deflection prediction models is assessed for cracked prestressed concrete flexural members with bonded steel tendons. Current models for computing deflection are based on an effective moment of inertia (with or without an offset moment for the cracked section response) or a bilinear moment-deflection response using the moment of inertia of the uncracked section before cracking and moment of inertia of the cracked section after cracking. The accuracy of the approaches provided in ACI 318-19, the PCI Design Handbook, and elsewhere are examined for computing immediate deflection using a large database of 180 fully prestressed as well as partially prestressed beams. Parameters considered in the analysis include the effect of tension-stiffening, reinforcement ratio, prestressing type (fully or partially prestressed), cracking moment, concrete elastic modulus, modulus of rupture, and the use of transformed or gross section properties. Results highlight the need for a rational model that can be universally applied to reinforced as well as prestressed concrete flexural members. Keywords: deflection; effective moment of inertia; partially prestressed; prestressed concrete.