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In this chapter the linearized Riemann tensor correlator on a de Sitter background including one-loop corrections from conformal fields is derived. The Riemann tensor correlation function exhibits interesting features: it is gauge-invariant even when including contributions from loops of matter fields, but excluding graviton loops as it is implemented in the 1/N expansion, it is compatible with de Sitter invariance, and provides a complete characterization of the local geometry. The two-point correlator function of the Riemann tensor is computed by taking suitable derivatives of the metric correlator function found in the previous chapter, and the result is written in a manifestly de Sitter-invariant form. Moreover, given the decomposition of the Riemann tensor in terms of Weyl and Ricci tensors, we write the explicit results for the Weyl and Ricci tensors correlators as well as the Weyl–Ricci tensors correlator and study both their subhorizon and superhorizon behavior. These results are extended to general conformal field theories. We also derive the Riemann tensor correlator in Minkowski spacetime in a manifestly Lorentz-invariant form by carefully taking the flat-space limit of our result in de Sitter.
As a short introduction to this chapter we first briefly summarize the in-in or closed-time-path (CTP) functional formalism and evaluate the CTP effective action for a scalar field in Minkowski spacetime. We then consider N quantum matter fields interacting with the gravitational field assuming an effective field theory approach to quantum gravity and consider the quantization of metric perturbations around a semiclassical background in the CTP formalism. A suitable prescription is given to select an asymptotic initial vacuum state of the interacting theory; this prescription plays an important role in calculations in later chapters. We derive expressions for the two-point metric correlations, which are conveniently written in terms of the CTP effective action that results from integrating out the matter fields by rescaling the gravitational constant and performing a 1/N expansion. These correlations include loop corrections from matter fields but no graviton loops. This is achieved consistently in the 1/N expansion, and is illustrated in a simplified model of matter–gravity interaction.
Structure formation in the early universe is a key problem in modern cosmology. In this chapter we discuss stochastic gravity as an alternative framework for studying the generation of primordial inhomogeneities in inflationary models, which can easily incorporate effects that go beyond the linear perturbations of the inflaton field. We show that the correlation functions that follow from the Einstein–Langevin equation, which emerge in the framework of stochastic gravity, coincide with that obtained with the usual quantization procedures when both the metric perturbations and the inflaton fluctuations are linear. Stochastic gravity, however, can also deal very naturally with the fluctuations of the inflaton field beyond the linear approximation. Here, we illustrate the stochastic approach with one of the simplest chaotic inflationary models in which the background spacetime is a quasi de Sitter universe, and prove the equivalence of the stochastic and quantum correlations to the linear order.
In this chapter we present the Schwinger–Keldysh effective action in the so-called ‘in-in’, or ‘closed-time-path’ (CTP) formalism necessary for the derivation of the dynamics of expectation values. The real and causal equation of motion derived therefrom ameliorates the deficiency of the ‘in-out’ effective action which produces an acausal equation of motion for an effective geometry that is complex, thus marring the physical meaning of effects related to backreaction, such as dissipation. We construct the in-in effective action for quantum fields in curved spacetime, show that the regularization required is the same as in the in-out formulation, and show how it can be used to treat problems in nonequilibrium quantum processes by considering initial states described by a density matrix. We then show two applications: (1) the damping of anisotropy in a Bianchi Type I universe from the semiclassical Einstein equation for conformal fields derived from the CTP effective action; and (2) higher-loop calculations, renormalization of the in-in effective action, and the calculation of vacuum expectation values of the stress-energy tensor for a Phi-4 field. The last part describes thermal field theory in its CTP formulation.
In this chapter we derive the full two-point quantum metric perturbations on a de Sitter background including one-loop corrections from conformal fields. We do the calculation using the CTP effective action with the 1/N expansion, and select an asymptotic initial state by a suitable prescription that defines the vacuum of the interacting theory. The decomposition of the metric perturbations into scalar, vector and tensor perturbations is reviewed, and the effective action is given in terms of that decomposition. We first compute the two-point function of the tensor perturbations, which are dynamical degrees of freedom. The relation with the intrinsic and induced fluctuations of stochastic gravity is discussed. We then compute the two-point metric perturbations for the scalar and vector modes, which are constrained degrees of freedom. The result for the full two-point metric perturbations is invariant under spatial rotations and translations as well as under a simultaneous rescaling of the spatial and conformal time coordinates. Finally, our results are extended to general conformal field theories, even strongly interacting ones, by deriving the effective action for a general conformal field theory.
Velvetleaf is an economically important weed in popcorn production fields in Nebraska. Many PRE herbicides in popcorn have limited residual activity or provide partial velvetleaf control. There are a limited number of herbicides applied POST in popcorn compared to field corn, necessitating the evaluation of POST herbicides for control of velvetleaf. The objectives of this study were to (1) evaluate the efficacy and crop safety of labeled POST herbicides for controlling velvetleaf that survived S-metolachlor/atrazine applied PRE and (2) determine effect of velvetleaf height on POST herbicide efficacy, popcorn injury, and yield. Field experiments were conducted in 2018 and 2019 near Clay Center, Nebraska. The experiments were arranged in a split-plot design with four replications. The main plot treatments were velvetleaf heights (up to 15 cm and up to 30 cm) and sub-plot treatments included a no-POST herbicide control, and eleven POST herbicide programs. Fluthiacet-methyl, fluthiacet-methyl/mesotrione, carfentrazone-ethyl, dicamba, and dicamba/diflufenzopyr provided > 96% velvetleaf control 28 DAT, reduced velvetleaf density to < 7 plants m─2, achieved 99 to 100% biomass reduction, and no effect on popcorn yield. Herbicide programs tested in this study provided > 98% control of velvetleaf 28 DAT in 2019. Most POST herbicide programs in this study provided > 90% control of up to 15 cm and up to 30 cm velvetleaf and no differences between velvetleaf heights in density, biomass reduction, or popcorn yield were observed, except topramezone and nicosulfuron/mesotrione 28 d after treatment (DAT) in 2018. Based on contrast analysis, herbicide programs with fluthiacet-methyl or dicamba provided better control than herbicide programs without them at 28 DAT in 2018. It is concluded that POST herbicides are available for control of up to 30 cm tall velvetleaf in popcorn production fields.
Field hospitals are usually deployed to locations where, in response to adverse circumstances, normal health care is challenged. It is known that the prevalence of burn wounds in such situations is raised and it is highly likely that a field hospital will need to provide burn care. Many of the features of modern high-quality burn care are not deliverable in a field hospital and it is unlikely the best outcomes can be achieved. Burn care draws heavily on resources. Burns over about 30% total body surface area may cause significant physiological derangement requiring sophisticated critical care. If definitive surgical care of the wound is to be undertaken it is probably better to delay wound excision for about two weeks to allow superficial burns to heal spontaneously. Surgery should ideally be performed in repeated short sessions rather than a single large procedure.
Two-dimensional problems of plane stress and plane strain in polar coordinates, both axisymmetric and non-axisymmetric, are considered. Among axisymmetric problems, the bending of a curved beam by two end couples and the problem of a pressurized hollow disk or cylinder are analyzed. Among non-axisymmetric problems, solutions are derived for problems of bending of a curved cantilever beam by a vertical force, loading of a circular hole in an infinite medium, concentrated vertical and tangential forces at the boundary of a half-plane, and a semi-elliptical pressure distribution over the boundary of a half-space. The problems of diametral compression of a circular disk (Michell problem), stretching of a large plate weakened by a small circular hole (Kirsch problem), stretching of a large plate strengthened by a small circular inhomogeneity, and spinning of a circular disk are also analyzed and discussed. The chapter ends with an analysis of the stress field near a crack tip under symmetric and antisymmetric remote loadings, the stress and displacement fields around an edge dislocation in an infinite medium, and around a concentrated force in an infinite plate.
Field hospitals can play a key role in the clinical treatment and public health management of infectious diseases during emergency situations, both in the setting of disasters primarily of an epidemic nature and of outbreaks that result secondarily in the midst of other crises. Planning and preparation are key components to successful operation in these settings and present unique issues compared to more routine field hospital scenarios absent a contagious threat. Special consideration needs to be given to site selection, the physical structure of a facility, infection prevention and control measures, personal protection, selection and training of staff, data collection and sharing, and clinical standard operating procedures. The mission of field hospitals can be expanded beyond clinical care to help stabilize epidemics through ensuring basic living conditions are available, including the provision of adequate food, clean water, sanitation, and shelter. The public health focused activities of a field hospital should include community-based prevention and health promotion activities, risk communication, and disease surveillance and control: all of which may provide invaluable contributions to broader public health response efforts during crisis.
Providing humanitarian relief to affected populations is a top priority following a major sudden onset disaster (SOD). The main form of medical relief to affected areas is the emergency medical teams (EMTs). These are groups of health professionals and support staff operating locally or outside their country of origin by providing healthcare to disaster-affected populations. Despite best intentions, for decades EMTs were disorganized and followed no clear standards. In the aftermath of the 2010 Haiti earthquake, the EMT Working Group of the World Health Organization‘s global health cluster initiated a global effort to standardize the EMTs system. This new system was put to the test in 2013 with the deployment of medical aid to the Philippines following Typhon Haiyan, and later on during the Ebola outbreak in West Africa and the earthquake in Nepal in 2015. This chapter reviews the history of medical aid to disaster affected areas, the process of coordinating and standardizing EMTs and the latest implementation of the new EMT coordination system.
Males and females are affected differently by natural disasters due to biologic, social, cultural, and reproductive health differences. Out of the female population, 25% are in the reproductive stage of their lives (age 15–45) and 20% of them are pregnant. While as many as 10% of natural disaster victims seeking medical assistance may need an obstetrician or gynecologist, these needs are not usually given high selection priority, whereupon rescue teams are likely to lack those essential specialists. The chapter gives clinical guidelines for managing labor in field hospital settings and dealing with ethical issues arising from treating pregnant women in disaster areas. Based on the literature and the authors’ experience, this chapter covers the effects of a disaster on women’s health in general and especially on pregnant women. The recommendation for the obstetric/gynecologic team composition, the medications and medical equipment needs, and how to arrange an Ob/Gyn department in a field hospital are given. The chapter gives clinical guidelines for managing labor in field hospital settings and dealing with ethical issues arising from treating pregnant women in disaster areas.
The chapter lists the recommendations on prevention and management of the consequences of sexual violence, reduction of HIV transmission, prevention of excess maternal and neonatal mortality and morbidity, and planning of comprehensive reproductive health services in the early days and weeks of an emergency.
The role of the ophthalmologist in the field hospital is important and irreplaceable; ocular injuries during a disaster can result in considerable disability and often require the care of an ophthalmologic surgeon. The ophthalmology field is a high technology area with the need for expensive equipment that are not available in the field hospital. The working scenario for the ophthalmologist in the delegation is very different than the one existing in a hospital in developed countries; therefore, first and foremost, a change in mental attitude is needed.
Understanding the characteristics of ocular injuries during various types of disasters in different geographical areas is important to be able to prepare for them properly, both mentally and practically.
Another dominant factor is time: the nature of ophthalmology patient’s varies significantly as time passes.
While in the first days after the disaster most ocular injuries are related to disaster, as time passes most of the referral patients are nondisaster related injuries such as chronic ocular problems of the local population.
This chapter covers the preparation needed for treating ocular injuries during disasters and the ophthalmology layout in the field hospital scenario.
The choice of the anesthetic technique in austere environments is dictated by the availability of medical personnel, electricity, oxygen, and supplies. TIVA appears to be a very promising, reliable alternative for the future of field anesthesia given its safety, simplicity, rapid setup, and small logistical footprint. Therefore, more anesthesia providers need to be trained and educated to be familiar and comfortable with administration of TIVA. Whenever regional nerve block anesthesia use is appropriate, it can be another excellent choice to provide better acute pain control and decrease postoperative complications in austere environments. There is no perfect analgesic, and hence multimodal approach for pain management is imperative. Early pain treatment has been proven to decrease chronicity, improve functionality, and reduce the risk of subsequent development psychological morbidities such as PTSD and depression. The chapter lists the recommendations on prevention and management of the consequences of sexual violence, reduction of HIV transmission, prevention of excess maternal and neonatal mortality and morbidity, and planning of comprehensive reproductive health services in the early days and weeks of an emergency.
Orthopedic treatment in a field hospital setting differs significantly from that in everyday practice in a high-income country. Field hospitals are deployed in a variety of scenarios, most commonly following earthquakes and armed conflicts, which cause a high incidence of musculoskeletal injuries. One should anticipate a large caseload of life and limb threatening injuries, delayed presentation with subsequent infections, limited operating theatre sterility, and a paucity of imaging, instrumentation, and fixation hardware.
These limitations dictate a damage control treatment approach, which includes “life over limb"": prioritizing life saving to limb saving procedures. Contamination and infection are treated by aggressive surgical debridement of contaminants and non-viable tissues. Fracture fixation is performed using the simplest and quickest methods; usually external fixation for open fractures casting for closed fractures, avoiding open reduction and internal fixation due to limited surgical sterility.
Indications for amputation include non-viable limbs due to irreparable vascular damage or severe crush injuries and infections uncontrollable by surgical and medical means.
Surgical decisions should take into account the cultural variability in the disaster milieu and informed consent should be obtained using interpreters, family and community members, and local medical personnel.
Effective administration of healthcare in an emergency setting, especially in field-hospital deployment where order must be established, needs assessed and limited resources allocated effectively, is considerably more complex than the regular patient–doctor interactions characteristic of routine times. Due to the complexity and uncertainty typical of such an environment, leadership is required not only by the field hospital staff but also by the affected public, which seeks leadership in those who are perceived to be the center of clinical service delivery.
This type of leadership demands organized command and control and practice of more than just basic leadership processes, and therefore requires, alongside the mission leader, a structured management and task-orientated chain of command.
For the hospital to operate effectively and independently, it is necessary to also define the organizational structure. The organizational structure discussed in this chapter is a model tested over the past three decades by the IDF Medical Corps hospital in numerous missions. This structure is generally similar to the basic structure of a small- to medium-scale hospital in routine times. At the same time, it allows more focused and simple managing processes required in non-routine scenarios such as emergencies or disasters.
Acute injuries contribute to significant morbidity in the immediate time following high magnitude earthquake. Illnesses resulting from poor shelter and lack of access to electricity, clean water, and sanitation will appear later.
The most common complaints are respiratory, gastrointestinal, genitourinary, malnutrition, and acute stress disorder.
Ambulatory service can be delivered as a department within the field hospital or by outreach. The triage is a crucial part of the clinic and the medical team should identify patients who could most benefit. Other parts of the ambulatory service should contain consultation area, treatment area, pharmacy and laboratory.
In the initial period the primary physicians will participate in triage of trauma patients, treating minor trauma and preparing patients for surgery. Therefore, they should be skilled in emergency medicine, ATLS and minor trauma.
Later on, the primary physician may lead the postoperative management and the last efforts will be treatment of acute problems emerging due to poor sanitation and crowding and also management of chronic medical problems. For this purpose, they should be familiar with common infections in the disaster area and antibiotic resistance. And finally, communication with local health-care services as well as public and religious facilities is mandatory.
Past experiences from uncoordinated and inefficient medical responses to disasters have prompted the WHO to formulate a system that includes minimum standards to which responding medical teams must adhere. Three levels of EMTs are identified: type 1 provides primary outpatient care, type 2 provides intermediate inpatient care, while type 3 provides specialized care. Following larger disasters, the affected country may request international EMT assistance. This assistance will be supported by the WHO. The health-care needs, and thus need for EMTs, will vary depending on type, scale of disaster, and the affected country’s vulnerability. A significant part of the EMT workload will be managing the normal burden of disease. A thorough needs assessment is vital for an effective response and should address anticipated health needs (and their variation over time), local resources available, and seek to gain intelligence on other context-specific challenges. EMTs do not function in isolation, but in a health system coordinated by the affected country. Efforts including the WHO EMT minimum standards system that verify international EMTS are important steps to ensure appropriate standards in a multitude of aspects of global disaster response.
The place of the critical care unit activation, within a field hospital, deployed to disaster area is challenged. Criteria used in the decision-making of activation are facility capabilities, combined with the event characteristics itself. The development of current concepts of critical care has allowed the survival of patients with advanced illness and injury. Since this discipline involves maximal lifesaving interventions, it was kept out of the scope of most field hospitals deployments among the world. Providing critical care is challenged by lack of medical information, and by the fact that a field ICU team, based on the reserve forces is gathered from few different acting ICUs of regular hospitals. Bridging those gaps is mandatory for a proper operation of a field ICU. As for the medical team, the nursing team is generally based on the reserve forces. It is gathered from various civilian and military facilities, with different daily practices and routines. Unifying those in the short time available, until full operation of the field ICU, can be an obstacle. Imaging modalities, laboratory services, documentation, and equipment issues are to be considered when planning for the field ICU activation. All those, including complex ethical difficulties to be solve, in spite of language and cultural barriers, are discussed in this chapter.
According to the World Heath Organization's (WHO) EMT initiative, teams must meet an agreed set of standards, both clinically and logistically. EMTs must be self-sustainable and not create a burden on the already stretched resources of a host nation.
The technical demands of field hospitals require logistical personnel with specialist skills, which ensures a field hospital can continue to function when all around them has been destroyed. They must be multiskilled to fulfill multiple roles within the team.
A collection of tents does not constitute a field hospital: methodical planning around safety and security, patient flow, and overall functionality is a necessity. Field hospitals require large volumes of clean water that meets or exceeds the WHO standards of potable water; consequently, EMTs must understand the requirements of self sustainability, water quality, and quantities for the delivery of services they are offering. WASH requires an expertise and the capacity and capability to deliver high levels of WASH irrespective of the circumstances. Leading by example in health care to other health-care personnel and facilities is a essential criteria of an EMT: technical logistics is key to achieving this.
It is highly likely that a field hospital will need to provide wound care. The very presence of a field hospital indicates that a situation exists where normal healthcare is challenged. It is important that staff understand the situation as it directly impacts on the type of care that should be delivered. The wrong type of care will not just yield suboptimal results for the patients, but will adversely affect workload, impact on resources, and compromise the effectiveness of the facility. Achieving good outcomes in wound care is dependent on ensuring the patient’s general well-being is optimised. The core requirement for wound care is initial wound surgery, which fully evaluates the wound as well as performing debridement and essential immediate interventions. Wounds associated with conflict and disaster should not be primarily closed. Healing is achieved by delayed primary closure or later complex reconstruction.